Ocean SSTs Tepid in August

globpopThe best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

HadSST is generally regarded as the best of the global SST data sets, and so the temperature story here comes from that source, the latest version being HadSST3.  More on what distinguishes HadSST3 from other SST products at the end.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST3 starting in 2015 through August 2018

Hadsst082018

A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016.  2018 started with slow warming after the low point of December 2017, led by steadily rising NH. Since 4/2018 SH and Tropics cooled slightly in the Spring and NH dipped in July 2018.  Now in August all ocean regions bumped upward.

Note that higher temps in 2015 and 2016 were first of all due to a sharp rise in Tropical SST, beginning in March 2015, peaking in January 2016, and steadily declining back below its beginning level. Secondly, the Northern Hemisphere added three bumps on the shoulders of Tropical warming, with peaks in August of each year.  Also, note that the global release of heat was not dramatic, due to the Southern Hemisphere offsetting the Northern one.

2018 is the coolest August since 2013 Globally, in NH and the Tropics.  In the SH August 2018 is matching 2017. The biggest difference from August 2015 is the Tropics anomaly being 0.36C lower this year (half of 0.74C in 2015).

A longer view of SSTs

The graph below  is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July.

Hadsst95to082018

Open image in new tab to enlarge.

1995 is a reasonable starting point prior to the first El Nino.  The sharp Tropical rise peaking in 1998 is dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99.  For the next 2 years, the Tropics stayed down, and the world’s oceans held steady around 0.2C above 1961 to 1990 average.

Then comes a steady rise over two years to a lesser peak Jan. 2003, but again uniformly pulling all oceans up around 0.4C.  Something changes at this point, with more hemispheric divergence than before. Over the 4 years until Jan 2007, the Tropics go through ups and downs, NH a series of ups and SH mostly downs.  As a result the Global average fluctuates around that same 0.4C, which also turns out to be the average for the entire record since 1995.

2007 stands out with a sharp drop in temperatures so that Jan.08 matches the low in Jan. ’99, but starting from a lower high. The oceans all decline as well, until temps build peaking in 2010.

Now again a different pattern appears.  The Tropics cool sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16, with July 2017 only slightly lower.  Note also that starting in 2014 SH plays a moderating role, offsetting the NH warming pulses. (Note: these are high anomalies on top of the highest absolute temps in the NH.)

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

But the peaks coming nearly every summer in HadSST require a different picture.  Let’s look at August, the hottest month in the North Atlantic from the Kaplan dataset.
AMO August 2018

The AMO Index is from from Kaplan SST v2, the unaltered and untrended dataset. By definition, the data are monthly average SSTs interpolated to a 5×5 grid over the North Atlantic basically 0 to 70N. The graph shows warming began after 1992 up to 1998, with a series of matching years since. Because the N. Atlantic has partnered with the Pacific ENSO recently, let’s take a closer look at some AMO years in the last 2 decades.

AMO decade 082018

This graph shows monthly AMO temps for some important years. The Peak years were 1998, 2010 and 2016, with the latter emphasized as the most recent. The other years show lesser warming, with 2007 emphasized as the coolest in the last 20 years. Note the red 2018 line is at the bottom of all these tracks. Most recently August 2018 is 0.34C lower than August 2016, and is the coolest August since 2007.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up?  Lower SSTs in July suggested climate change of the cooling variety, but August has offset that.  Once again, ENSO will probably determine the outcome.

Postscript:

In the most recent GWPF 2017 State of the Climate report, Dr. Humlum made this observation:

“It is instructive to consider the variation of the annual change rate of atmospheric CO2 together with the annual change rates for the global air temperature and global sea surface temperature (Figure 16). All three change rates clearly vary in concert, but with sea surface temperature rates leading the global temperature rates by a few months and atmospheric CO2 rates lagging 11–12 months behind the sea surface temperature rates.”

Footnote: Why Rely on HadSST3

HadSST3 is distinguished from other SST products because HadCRU (Hadley Climatic Research Unit) does not engage in SST interpolation, i.e. infilling estimated anomalies into grid cells lacking sufficient sampling in a given month. From reading the documentation and from queries to Met Office, this is their procedure.

HadSST3 imports data from gridcells containing ocean, excluding land cells. From past records, they have calculated daily and monthly average readings for each grid cell for the period 1961 to 1990. Those temperatures form the baseline from which anomalies are calculated.

In a given month, each gridcell with sufficient sampling is averaged for the month and then the baseline value for that cell and that month is subtracted, resulting in the monthly anomaly for that cell. All cells with monthly anomalies are averaged to produce global, hemispheric and tropical anomalies for the month, based on the cells in those locations. For example, Tropics averages include ocean grid cells lying between latitudes 20N and 20S.

Gridcells lacking sufficient sampling that month are left out of the averaging, and the uncertainty from such missing data is estimated. IMO that is more reasonable than inventing data to infill. And it seems that the Global Drifter Array displayed in the top image is providing more uniform coverage of the oceans than in the past.

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

 

N. Atlantic Cooling in 2018

RAPID Array measuring North Atlantic SSTs.

For the last few years, observers have been speculating about when the North Atlantic will start the next phase shift from warm to cold.

Source: Energy and Education Canada

An example is this report in May 2015 The Atlantic is entering a cool phase that will change the world’s weather by Gerald McCarthy and Evan Haigh of the RAPID Atlantic monitoring project. Excerpts in italics with my bolds.

This is known as the Atlantic Multidecadal Oscillation (AMO), and the transition between its positive and negative phases can be very rapid. For example, Atlantic temperatures declined by 0.1ºC per decade from the 1940s to the 1970s. By comparison, global surface warming is estimated at 0.5ºC per century – a rate twice as slow.

In many parts of the world, the AMO has been linked with decade-long temperature and rainfall trends. Certainly – and perhaps obviously – the mean temperature of islands downwind of the Atlantic such as Britain and Ireland show almost exactly the same temperature fluctuations as the AMO.

Atlantic oscillations are associated with the frequency of hurricanes and droughts. When the AMO is in the warm phase, there are more hurricanes in the Atlantic and droughts in the US Midwest tend to be more frequent and prolonged. In the Pacific Northwest, a positive AMO leads to more rainfall.

A negative AMO (cooler ocean) is associated with reduced rainfall in the vulnerable Sahel region of Africa. The prolonged negative AMO was associated with the infamous Ethiopian famine in the mid-1980s. In the UK it tends to mean reduced summer rainfall – the mythical “barbeque summer”.Our results show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres – the intergyre region. This a major influence on the wind patterns and the heat transferred between the atmosphere and ocean.

The observations that we do have of the Atlantic overturning circulation over the past ten years show that it is declining. As a result, we expect the AMO is moving to a negative (colder surface waters) phase. This is consistent with observations of temperature in the North Atlantic.

Cold “blobs” in North Atlantic have been reported, but they are usually a winter phenomena. For example in April 2016, the sst anomalies looked like this

But by September, the picture changed to this

And we know from Kaplan AMO dataset, that 2016 summer SSTs were right up there with 1998 and 2010 as the highest recorded.

As the graph above suggests, this body of water is also important for tropical cyclones, since warmer water provides more energy.  But those are annual averages, and I am interested in the summer pulses of warm water into the Arctic. As I have noted in my monthly HadSST3 reports, most summers since 2003 there have been warm pulses in the north atlantic.
AMO August 2018The AMO Index is from from Kaplan SST v2, the unaltered and untrended dataset. By definition, the data are monthly average SSTs interpolated to a 5×5 grid over the North Atlantic basically 0 to 70N.  The graph shows warming began after 1992 up to 1998, with a series of matching years since.  August is the hottest month in the dataset, and note the considerable drop from 2017 to August 2018.  Because McCarthy refers to hints of cooling to come in the N. Atlantic, let’s take a closer look at some AMO years in the last 2 decades.

AMO decade 082018

This graph shows monthly AMO temps for some important years. The Peak years were 1998, 2010 and 2016, with the latter emphasized as the most recent. The other years show lesser warming, with 2007 emphasized as the coolest in the last 20 years. Note the red 2018 line is at the bottom of all these tracks.  Most recently August 2018 is 0.34C lower than August 2016, and is the coolest August since 2007.

With all the talk of AMOC slowing down and a phase shift in the North Atlantic, we await SST measurements for August and September to confirm that cooling has set in.  As of August, the momentum is certainly heading downward, despite the band of warming ocean  that gave rise to now receding European heat waves.
cdas-sflux_ssta_atl_1

 

Ocean Air Temps Drop in August

Presently sea surface temperatures (SST) are the best available indicator of heat content gained or lost from earth’s climate system.  Enthalpy is the thermodynamic term for total heat content in a system, and humidity differences in air parcels affect enthalpy.  Measuring water temperature directly avoids distorted impressions from air measurements.  In addition, ocean covers 71% of the planet surface and thus dominates surface temperature estimates.  Eventually we will likely have reliable means of recording water temperatures at depth.

Recently, Dr. Ole Humlum reported from his research that air temperatures lag 2-3 months behind changes in SST.  He also observed that changes in CO2 atmospheric concentrations lag behind SST by 11-12 months.  This latter point is addressed in a previous post Who to Blame for Rising CO2?

The August update to HadSST3 will appear later this month, but in the meantime we can look at lower troposphere temperatures (TLT) from UAHv6 which are already posted for August. The temperature record is derived from microwave sounding units (MSU) on board satellites like the one pictured above.

The UAH dataset includes temperature results for air above the oceans, and thus should be most comparable to the SSTs. There is the additional feature that ocean air temps avoid Urban Heat Islands (UHI).  The graph below shows monthly anomalies for ocean temps since January 2015.

UAH Oceans 201808

Open image in new tab to enlarge.

Remarkably, the anomalies over the entire ocean dropped to the same value, 0.12C (Tropics are 0.13C).  In previous months both the Tropics and SH rose, while NH rose very slightly, resulting in a small increase in the Global average temp of air over oceans. Now that warming is gone in NH and Globally.

Taking a longer view, we can look at the record since 1995, that year being an ENSO neutral year and thus a reasonable starting point for considering the past two decades.  On that basis we can see the plateau in ocean temps is persisting. Since last October all oceans have cooled, with offsetting bumps up and down.

UAHv6 TLT 
Monthly Ocean
Anomalies
Average Since 1995 Ocean 8/2018
Global 0.13 0.12
NH 0.16 0.12
SH 0.11 0.12
Tropics 0.12 0.13

As of August 2018, Global ocean air temps as well as SH and Tropics are matching the average since 1995.  NH is now cooler than the average.  Globally,  2018 is the coolest August since 2013. NH, SH and the Tropics are the coolest August since 2014.

The details of UAH ocean temps are provided below.  The monthly data make for a noisy picture, but seasonal fluxes between January and July are important.

The greater volatility of the Tropics is evident, leading the oceans through three major El Nino events during this period.  Note also the flat period between 7/1999 and 7/2009.  The 2010 El Nino was erased by La Nina in 2011 and 2012.  Then the record shows a fairly steady rise peaking in 2016, with strong support from warmer NH anomalies, before returning to the 22-year average.

Summary

TLTs include mixing above the oceans and probably some influence from nearby more volatile land temps.  They started the recent cooling later than SSTs from HadSST3, but are now showing the same pattern.  It seems obvious that despite the three El Ninos, their warming has not persisted, and without them it would probably have cooled since 1995.  Of course, the future has not yet been written.

 

Cold Summer in Nunavut

 

A previous post explored the claim that “Nunavut is melting” and is reproduced below.  On September 6 Jane George posted at the Northwest Passage blog declaring the opposite:  As ice and snow return, summer’s over in Nunavut  “It was a cold summer.”  Excerpts below in italics with my bolds.
CanIce 20180908

This map from the Canadian Ice Service shows sea ice conditions in the western part of High Arctic islands on Sept. 8. The dark blue shows a low concentration (less than 10 per cent) of ice, while white shows a high concentration (100 per cent). At this time of the year, the Arctic ice cover is the highest it has been since 2014, the National Snow and Ice Data Center said Sept. 5.

Snow has now fallen across Nunavut’s more northerly communities, from Kugluktuk to Qikiqtarjuaq, after a summer that also brought cool temperatures and heavy ice conditions to some parts of Nunavut.

“if you’re trying to get somewhere, and ice is in the way, it’s been a very bad year,” said Gilles Langis, a senior ice forecaster with the Canadian Ice Service.

It remains unclear if ice played a role in the grounding of the Ioffe Akademik on Aug. 24. The cruise ship was not sailing where it was supposed to be due to ice, according to an account by the journalist and author Ed Struzik, who was on board.

And, earlier this week, operators of the cruise vessel Hanseatic turned around and headed back east through the Northwest Passage, having decided that ice conditions were too bad to continue on to western Nunavut.

The Canadian Coast Guard also recently rescued two sailors from a smaller vessel that had run into bad ice conditions in the Bellot Strait.

Summing up the summer ice conditions in 2018, Langis said that in many areas it was “very challenging”—in parts of Hudson Bay, Hudson Strait, Baffin Bay and at various choke points in the Northwest Passage where the ice pushed in.

Ice conditions are not likely to improve.  And as for the weather, it’s not likely not to be warming up either.

“It was a cold summer,” said Brian Proctor from Environment Canada. As well, northern Canada saw above normal precipitation in many communities because of a low pressure front stalled over the North.

Iqaluit experienced its 13th coldest and 14th wettest year in 73 years, he said.

In Qikiqtarjuaq, where snow also came early, it was the seventh coldest summer in 22 years.

Previous post:  Nunavut is Melting!  Or not.

From Yale Climate Connections we heard last week about Nunavut melting and a theatrical production to spread news and concerns about this dangerous development.

“I come from a place of rugged mountains, imperial glaciers and tender-covered permafrost. But Nunavut, our land, is only as rich as it is cold, and today most of it is melting.”That’s Chantal Bilodeau, reading a passage from “Sila,” a play about the effects of climate change in the Arctic.

The characters in her play include polar bears, an Inuit goddess, scientists, and coast guard officers – all working together to save their land.

No doubt her personal experience and feelings for her Nunavut are sincere and profound. (Originally I thought it was her homeland, but in fact she is a New York playwright and translator, born in Montreal.) And there will be a large audience receptive to her concerns about global warming. (Bilodeau has writen six plays about the Arctic and founded the international network Artists And Climate Change.) But I wonder if scientific measurements support her belief that Nunavut is melting.

After all, we have learned from medical research that individual life experiences (anecdotes) may not be true more generally. That is why drugs are tested on population samples with double-blind studies: neither the patient nor the doctor knows who gets the medicine and who gets the placebo.

So I went looking for weather station records to see what is the warming trend in that region. As curiosity does so often, it led me on a journey of discovery, learning some new things, and relearning old ones with fresh implications.

Where are temperatures measured in Nunavut?

It is by far the Northernmost territory of Canada, just off the coast of Northern Greenland.

According to Environment Canada, weather is reported at 29 places in Nunavut. So I went to look at the record at Iqaluit, the capital of the territory. You get monthly normals for the period 1981 to 2010. Historical data (daily averages) can be accessed only 1 individual month/year at a time, the menu stops at 2004. Even then, some months are filled with “M” for missing. Historical data from which trends can be analyzed is hard to come by.

Disappearing Weather Records

It turns out that Nunavut also suffered from the great purging of weather station records that was noticed by skeptics years ago.

Ave. T vs. No. Stations

Graph showing the correlation between Global Mean Temperature (Average T) and the number of stations included in the global database. Source: Ross McKitrick, U of Guelph

I was aware of this because of a recent study looking at trends at stations around the Arctic circle. Arctic Warming Unalarming.  That study included graphs that showed the dramatic removal of station records in the North.  Though the depletion was not limited to the far North, many Canadian and Russian records disappeared from the global database.

arctic-europe-paper-2015_fig6annual

Fig. 6 Temperature change for annual Arctic averages relative to the temperature during 1961 to 1990 for stations in Europe having more than 150 years of observations. The red curve is the moving 5-year average while the blue curve shows the number of stations reporting in each year. 118 stations contributed to the study. W. A. van Wijngaarden, Theoretical & Applied Climatology (2015)

Eureka, Nunavut, Canada “Last Station above latitude 65N”

Eureka got considerable attention in 2010 due to its surviving the dying out of weather stations. The phrase in quotes above reflects an observation that GISS uses Eureka data to infill across the whole Arctic Circle. That single station record is hugely magnified in its global impact in that temperature reconstruction product. Somewhat like the influence of a single tree in Yamal upon the infamous hockey stick graph.

The first High Arctic Weather Station in history, Eureka was established in April 1947 at 80-degrees north latitude in the vicinity of two rivers, which provided fresh water to the six-man United States Army Air Force team that parachuted in. They erected Jamesway huts to shelter themselves and their equipment until August, when an icebreaker reached Eureka – as it has every year since – and brought permanent buildings and supplies. For decades after that, small, all-male crews would hunker down for entire winters, going a little stir-crazy from the isolation. WUWT 2010

GHCN Records for Nunavut

It turns out that in addition to Eureka, GCHN has data for Alert and Clyde (River), but the latter two histories end in 2004 and 2010, respectively. The adjusted files have a few differences in details, but little change from the unadjusted files. The chart below shows the temperatures measured at Eureka, Nunavut, Canada 79° 98’ N, 85° 93’ W.  The other two stations tell the same story as Eureka, though temperatures at Clyde are warmer in absolute terms due to its more Southerly location.

Eureka temps4

The chart shows Annual, July and January averages along with the lifetime averages of Eureka station from 1948 through 2015.  There is slight variability, and a few years higher than average, but nothing alarming or even enough for people to sense any change.  Note also that annual averages are well below freezing, because only 3 months are above 0° C.  I suppose that someone could play with anomalies and generate a chart that looked scary, but the numbers in the record do not support fears of global warming and melting in Nunavut.

Conclusion

Once again we see media announcements that confuse subjective beliefs with empirical observations of objective reality.  And unfortunately, those observations are less and less available to counter the herd instincts of fearing the future and blaming someone.

 

Earth’s “Big Freeze” Looms

Earth’s “Big Freeze” Looms As Sun Remains Devoid Of Sunspots For Most Of 2018 is an article from Zero Hedge. Excerpts in italics.

 

Scientists are reporting that the sun has been free of sunspots for a total of 133 days this year, according to The Express UK. With only 241 days of 2018 passing, that means the sun has been blank for the majority of the year. Experts continue to warn that this is a sign that the solar minimum is on its way.

“The sun is spotless again. For the 133rd day this year, the face of the sun is blank,” wrote the website Space Weather.

“Solar minimum has returned, bringing extra cosmic rays, long-lasting holes in the sun’s atmosphere, and strangely pink auroras,” the website continued.

The sun follows a cycle of roughly 11 years where it reaches a solar maximum and then a solar minimum.

During a solar maximum, the sun gives off more heat and solar particles and is littered with sunspots. Less heat in a solar minimum is due to a decrease in the sun’s magnetic waves. Our sun was not expected to head into a solar minimum until around 2020, but it appears to be heading in that direction a little early which could prove to be bad news for warm weather lovers.

 

But a prolonged solar minimum could mean a “mini ice age.” The last time there was a prolonged solar minimum, it did, in fact, lead to a mini ice-age which was scientifically known as the Maunder minimum. That little cold snap lasted for 70 years between the years 1645 and 1715. During this period, temperatures dropped globally by 1.3 degrees Celsius leading to shorter seasons and ultimately food shortages.

“Low solar activity is known to have consequences on Earth’s weather and climate and it also is well correlated with an increase in cosmic rays that reach the upper part of the atmosphere. The blank sun is a sign that the next solar minimum is approaching and there will be an increasing number of spotless days over the next few years,” wrote a meteorological website called Vencore Weather.

Clear Thinking about Heat Records

Photo illustration by Slate. Photos by Thinkstock.

Here is an analysis using critical intelligence to interpret media reports about temperature records this summer. Daniel Engber writes in Slate Crazy From the Heat

The subtitle is Climate change is real. Record-high temperatures everywhere are fake.  As we shall see from the excerpts below, The first sentence is a statement of faith, since as Engber demonstrates, the notion does not follow from the temperature evidence. Excerpts in italics with my bolds.

It’s been really, really hot this summer. How hot? Last Friday, the Washington Post put out a series of maps and charts to illustrate the “record-crushing heat.” All-time temperature highs have been measured in “scores of locations on every continent north of the equator,” the article said, while the lower 48 states endured the hottest-ever stretch of temperatures from May until July.

These were not the only records to be set in 2018. Historic heat waves have been crashing all around the world, with records getting shattered in Japan, broken on the eastern coast of Canada, smashed in California, and rewritten in the Upper Midwest. A city in Algeria suffered through the highest high temperature ever recorded in Africa. A village in Oman set a new world record for the highest-ever low temperature. At the end of July, the New York Times ran a feature on how this year’s “record heat wreaked havoc on four continents.” USA Today reported that more than 1,900 heat records had been tied or beaten in just the last few days of May.

While the odds that any given record will be broken may be very, very small, the total number of potential records is mind-blowingly enormous.

There were lots of other records, too, lots and lots and lots—but I think it’s best for me to stop right here. In fact, I think it’s best for all of us to stop reporting on these misleading, imbecilic stats. “Record-setting heat,” as it’s presented in news reports, isn’t really scientific, and it’s almost always insignificant. And yet, every summer seems to bring a flood of new superlatives that pump us full of dread about the changing climate. We’d all be better off without this phony grandiosity, which makes it seem like every hot and humid August is unparalleled in human history. It’s not. Reports that tell us otherwise should be banished from the news.

It’s true the Earth is warming overall, and the record-breaking heat that matters most—the kind we’d be crazy to ignore—is measured on a global scale. The average temperature across the surface of the planet in 2017 was 58.51 degrees, one-and-a-half degrees above the mean for the 20th century. These records matter: 17 of the 18 hottest years on planet Earth have occurred since 2001, and the four hottest-ever years were 2014, 2015, 2016, and 2017. It also matters that this changing climate will result in huge numbers of heat-related deaths. Please pay attention to these terrifying and important facts. Please ignore every other story about record-breaking heat.

You’ll often hear that these two phenomena are related, that local heat records reflect—and therefore illustrate—the global trend. Writing in Slate this past July, Irineo Cabreros explained that climate change does indeed increase the odds of extreme events, making record-breaking heat more likely. News reports often make this point, linking probabilities of rare events to the broader warming pattern. “Scientists say there’s little doubt that the ratcheting up of global greenhouse gases makes heat waves more frequent and more intense,” noted the Times in its piece on record temperatures in Algeria, Hong Kong, Pakistan, and Norway.

Yet this lesson is subtler than it seems. The rash of “record-crushing heat” reports suggest we’re living through a spreading plague of new extremes—that the rate at which we’re reaching highest highs and highest lows is speeding up. When the Post reports that heat records have been set “at scores of locations on every continent,” it makes us think this is unexpected. It suggests that as the Earth gets ever warmer, and the weather less predictable, such records will be broken far more often than they ever have before.

But that’s just not the case. In 2009, climatologist Gerald Meehl and several colleagues published an analysis of records drawn from roughly 2,000 weather stations in the U.S. between 1950 and 2006. There were tens of millions of data points in all—temperature highs and lows from every station, taken every day for more than a half-century. Meehl searched these numbers for the record-setting values—i.e., the days on which a given weather station saw its highest-ever high or lowest-ever low up until that point. When he plotted these by year, they fell along a downward-curving line. Around 50,000 new heat records were being set every year during the 1960s; then that number dropped to roughly 20,000 in the 1980s, and to 15,000 by the turn of the millennium.

From Meehl et al 2009.

This shouldn’t be surprising. As a rule, weather records will be set less frequently as time goes by. The first measurement of temperature that’s ever taken at a given weather station will be its highest (and lowest) of all time, by definition. There’s a good chance that the same station’s reading on Day 2 will be a record, too, since it only needs to beat the temperature recorded on Day 1. But as the weeks and months go by, this record-setting contest gets increasingly competitive: Each new daily temperature must now outdo every single one that came before. If the weather were completely random, we might peg the chances of a record being set at any time as 1/n, where n is the number of days recorded to that point. In other words, one week into your record-keeping, you’d have a 1 in 7 chance of landing on an all-time high. On the 100th day, your odds would have dropped to 1 percent. After 56 years, your chances would be very, very slim.

The weather isn’t random, though; we know it’s warming overall, from one decade to the next. That’s what Meehl et al. were looking at: They figured that a changing climate would tweak those probabilities, goosing the rate of record-breaking highs and tamping down the rate of record-breaking lows. This wouldn’t change the fundamental fact that records get broken much less often as the years go by. (Even though the world is warming, you’d still expect fewer heat records to be set in 2000 than in 1965.) Still, one might guess that climate change would affect the rate, so that more heat records would be set than we’d otherwise expect.

That’s not what Meehl found. Between 1950 and 2006, the rate of record-breaking heat seemed unaffected by large-scale changes to the climate: The number of new records set every year went down from one decade to the next, at a rate that matched up pretty well with what you’d see if the odds were always 1/n. The study did find something more important, though: Record-breaking lows were showing up much less often than expected. From one decade to the next, fewer records of any kind were being set, but the ratio of record lows to record highs was getting smaller over time. By the 2000s, it had fallen to about 0.5, meaning that the U.S. was seeing half as many record-breaking lows as record-breaking highs. (Meehl has since extended this analysis using data going back to 1930 and up through 2015. The results came out the same.)

Source: Intellicast, using raw unadjusted data.

What does all this mean? On one hand, it’s very good evidence that climate change has tweaked the odds for record-breaking weather, at least when it comes to record lows. (Other studies have come to the same conclusion.) On the other hand, it tells us that in the U.S., at least, we’re not hitting record highs more often than we were before, and that the rate isn’t higher than what you’d expect if there weren’t any global warming. In fact, just the opposite is true: As one might expect, heat records are getting broken less often over time, and it’s likely there will be fewer during the 2010s than at any point since people started keeping track.

This may be hard to fathom, given how much coverage has been devoted to the latest bouts of record-setting heat. These extreme events are more unusual, in absolute terms, than they’ve ever been before, yet they’re always in the news. How could that be happening?

While the odds that any given record will be broken may be very, very small, the total number of potential records that could be broken—and then reported in the newspaper—is mind-blowingly enormous. To get a sense of how big this number really is, consider that the National Oceanic and Atmospheric Administration keeps a database of daily records from every U.S. weather station with at least 30 years of data, and that its website lets you search for how many all-time records have been set in any given stretch of time. For instance, the database indicates that during the seven-day period ending on Aug. 17—the date when the Washington Post published its series of “record-crushing heat” infographics—154 heat records were broken.

That may sound like a lot—154 record-high temperatures in the span of just one week. But the NOAA website also indicates how many potential records could have been achieved during that time: 18,953. In actuality, less than one percent of these were broken. You can also pull data on daily maximum temperatures for an entire month: I tried that with August 2017, and then again for months of August at 10-year intervals going back to the 1950s. Each time the query returned at least about 130,000 potential records, of which one or two thousand seemed to be getting broken every year. (There was no apparent trend toward more records being broken over time.)

Now let’s say there are 130,000 high-temperature records to be broken every month in the U.S. That’s only half the pool of heat-related records, since the database also lets you search for all-time highest low temperatures. You can also check whether any given highest high or highest low happens to be a record for the entire month in that location, or whether it’s a record when compared across all the weather stations everywhere on that particular day.

Add all of these together and the pool of potential heat records tracked by NOAA appears to number in the millions annually, of which tens of thousands may be broken. Even this vastly underestimates the number of potential records available for media concern. As they’re reported in the news, all-time weather records aren’t limited to just the highest highs or highest lows for a given day in one location. Take, for example, the first heat record mentioned in this column, reported in the Post: The U.S. has just endured the hottest May, June, and July of all time. The existence of that record presupposes many others: What about the hottest April, May and June, or the hottest March, April, and May? What about all the other ways that one might subdivide the calendar?

Geography provides another endless well of flexibility. Remember that the all-time record for the hottest May, June, and July applied only to the lower 48 states. Might a different set of records have been broken if we’d considered Hawaii and Alaska? And what about the records spanning smaller portions of the country, like the Midwest, or the Upper Midwest, or just the state of Minnesota, or just the Twin Cities? And what about the all-time records overseas, describing unprecedented heat in other countries or on other continents?

Even if we did limit ourselves to weather records from a single place measured over a common timescale, it would still be possible to parse out record-breaking heat in a thousand different ways. News reports give separate records, as we’ve seen, for the highest daily high and the highest daily low, but they also tell us when we’ve hit the highest average temperature over several days or several weeks or several months. The Post describes a recent record-breaking streak of days in San Diego with highs of at least 83 degrees. (You’ll find stories touting streaks of daily highs above almost any arbitrary threshold: 90 degrees, 77 degrees, 60 degrees, et cetera.) Records also needn’t focus on the temperature at all: There’s been lots of news in recent weeks about the fact that the U.K. has just endured its driest-ever early summer.

“Record-breaking” summer weather, then, can apply to pretty much any geographical location, over pretty much any span of time. It doesn’t even have to be a record—there’s an endless stream of stories on “near-record heat” in one place or another, or the “fifth-hottest” whatever to happen in wherever, or the fact that it’s been “one of the hottest” yadda-yaddas that yadda-yadda has ever seen. In the most perverse, insane extension of this genre, news outlets sometimes even highlight when a given record isn’t being set.

Loose reports of “record-breaking heat” only serve to puff up muggy weather and make it seem important. (The sham inflations of the wind chill factor do the same for winter months.) So don’t be fooled or flattered by this record-setting hype. Your summer misery is nothing special.

Summary

This article helps people not to confuse weather events with climate.  My disappointment is with the phrase, “Climate Change is Real,” since it is subject to misdirection.  Engber uses that phrase referring to rising average world temperatures, without explaining that such estimates are computer processed reconstructions since the earth has no “average temperature.”  More importantly the undefined “climate change” is a blank slate to which a number of meanings can be attached.

Some take it to mean: It is real that rising CO2 concentrations cause rising global warming.  Yet that is not supported by temperature records.
Others think it means: It is real that using fossil fuels causes global warming.  This too lacks persuasive evidence.
WFFC and Hadcrut 2018Over the last five decades the increase in fossil fuel consumption is dramatic and monotonic, steadily increasing by 234% from 3.5B to 11.7B oil equivalent tons. Meanwhile the GMT record from Hadcrut shows multiple ups and downs with an accumulated rise of 0.74C over 53 years, 5% of the starting value.

Others know that Global Mean Temperature is a slippery calculation subject to the selection of stations.

Graph showing the correlation between Global Mean Temperature (Average T) and the number of stations included in the global database. Source: Ross McKitrick, U of Guelph

Global warming estimates combine results from adjusted records.
Conclusion

The pattern of high and low records discussed above is consistent with natural variability rather than rising CO2 or fossil fuel consumption. Those of us not alarmed about the reported warming understand that “climate change” is something nature does all the time, and that the future is likely to include periods both cooler and warmer than now.

Background Reading:

The Climate Story (Illustrated)

2018 Update: Fossil Fuels ≠ Global Warming

Man Made Warming from Adjusting Data

What is Global Temperature? Is it warming or cooling?

Autumn Will Save Us from Climate Change

Hot, Hot, Hot.  You will have noticed that the term “climate change” is now synonymous with “summer”.  Since the northern hemisphere is where most of the world’s land, people and media are located, two typical summer months (June was not so hot) have been depicted as the fires of hell awaiting any and all who benefit from fossil fuels. If you were wondering what the media would do in the absence of hurricanes to heap upon our heads, you are getting the answer.

Fortunately, Autumn is on the way and already bringing cooler evenings in Montreal where I live. Once again open windows provide fresh air for sleeping, and mornings are starting to show condensation. This year’s period of “climate change” is winding down.  Unless of course, we get some hurricanes the next two months.  Below is a repost of seasonal changes in temperature and climate for those who may have been misled by the media reports of a forever hotter future.

geese-in-v-formation

Autumnal Climate Change

Seeing a lot more of this lately, along with hearing the geese  honking. And in the next month or so, we expect that trees around here will lose their leaves. It definitely is climate change of the seasonal variety.

Interestingly, the science on this is settled: It is all due to reduction of solar energy because of the shorter length of days (LOD). The trees drop their leaves and go dormant because of less sunlight, not because of lower temperatures. The latter is an effect, not the cause.

Of course, the farther north you go, the more remarkable the seasonal climate change. St. Petersburg, Russia has their balmy “White Nights” in June when twilight is as dark as it gets, followed by the cold, dark winter and a chance to see the Northern Lights.

And as we have been monitoring, the Arctic ice has been melting from sunlight in recent months, but will soon begin to build again in the darkness to its maximum in March.

We can also expect in January and February for another migration of millions of Canadians (nicknamed “snowbirds”) to fly south in search of a summer-like climate to renew their memories and hopes. As was said to me by one man in Saskatchewan (part of the Canadian wheat breadbasket region): “Around here we have Triple-A farmers: April to August, and then Arizona.” Here’s what he was talking about: Quartzsite Arizona annually hosts 1.5M visitors, mostly between November and March.

Of course, this is just North America. Similar migrations occur in Europe, and in the Southern Hemisphere, the climates are changing in the opposite direction, Springtime currently. Since it is so obviously the sun causing this seasonal change, the question arises: Does the sunlight vary on longer than annual timescales?

The Solar-Climate Debate

And therein lies a great, enduring controversy between those (like the IPCC) who dismiss the sun as a driver of multi-Decadal climate change, and those who see a connection between solar cycles and Earth’s climate history. One side can be accused of ignoring the sun because of a prior commitment to CO2 as the climate “control knob”.

The other side is repeatedly denounced as “cyclomaniacs” in search of curve-fitting patterns to prove one or another thesis. It is also argued that a claim of 60-year cycles can not be validated with only 150 years or so of reliable data. That point has weight, but it is usually made by those on the CO2 bandwagon despite temperature and CO2 trends correlating for only 2 decades during the last century.

One scientist in this field is Nicola Scafetta, who presents the basic concept this way:

“The theory is very simple in words. The solar system is characterized by a set of specific gravitational oscillations due to the fact that the planets are moving around the sun. Everything in the solar system tends to synchronize to these frequencies beginning with the sun itself. The oscillating sun then causes equivalent cycles in the climate system. Also the moon acts on the climate system with its own harmonics. In conclusion we have a climate system that is mostly made of a set of complex cycles that mirror astronomical cycles. Consequently it is possible to use these harmonics to both approximately hindcast and forecast the harmonic component of the climate, at least on a global scale. This theory is supported by strong empirical evidences using the available solar and climatic data.”

He goes on to say:

“The global surface temperature record appears to be made of natural specific oscillations with a likely solar/astronomical origin plus a noncyclical anthropogenic contribution during the last decades. Indeed, because the boundary condition of the climate system is regulated also by astronomical harmonic forcings, the astronomical frequencies need to be part of the climate signal in the same way the tidal oscillations are regulated by soli-lunar harmonics.”

He has concluded that “at least 60% of the warming of the Earth observed since 1970 appears to be induced by natural cycles which are present in the solar system.” For the near future he predicts a stabilization of global temperature and cooling until 2030-2040.

For more see Scafetta vs. IPCC: Dueling Climate Theories

A Deeper, but Accessible Presentation of Solar-Climate Theory

I have found this presentation by Ian Wilson to be persuasive while honestly considering all of the complexities involved.

The author raises the question: What if there is a third factor that not only drives the variations in solar activity that we see on the Sun but also drives the changes that we see in climate here on the Earth?

The linked article is quite readable by a general audience, and comes to a similar conclusion as Scafetta above: There is a connection, but it is not simple cause and effect. And yes, length of day (LOD) is a factor beyond the annual cycle.

Click to access IanwilsonForum2008.pdf

It is fair to say that we are still at the theorizing stage of understanding a solar connection to earth’s climate. And at this stage, investigators look for correlations in the data and propose theories (explanations) for what mechanisms are at work. Interestingly, despite the lack of interest from the IPCC, solar and climate variability is a very active research field these days.

For example Svensmark has now a Cosmosclimatology theory supported by empirical studies described in more detail in the red link.

A summary of recent studies is provided at NoTricksZone: Since 2014, 400 Scientific Papers Affirm A Strong Sun-Climate Link

Ian Wilson has much more to say at his blog: http://astroclimateconnection.blogspot.com.au/

Once again, it appears that the world is more complicated than a simple cause and effect model suggests.

Fluctuations in observed global temperatures can be explained by a combination of oceanic and solar cycles.  See engineering analysis from first principles Quantifying Natural Climate Change.

For everything there is a season, a time for every purpose under heaven.

What has been will be again, what has been done will be done again;
there is nothing new under the sun.
(Ecclesiastes 3:1 and 1:9)

Footnote:

marching-orders

 

 

Christy’s Common Sense about Climate

An insightful straight-forward interview with Dr. John Christy published today at yellowhammernews  Alabama’s state climatologist John Christy rebuts claims of recent fires, heat waves being caused by human activity (H/T Climate Depot) Excerpts in italics with my bolds.

There is one particular word that Dr. John Christy turns to frequently for describing climate science: murky.

It’s a point of view foundational to his own research, and a message underpinning each of his twenty appearances before various congressional committees.

“It’s encouraging because they wouldn’t invite you back unless your message was compelling and not only compelling, but accurate,” Christy, Alabama’s state climatologist, told Yellowhammer News in an interview.

Christy, whose day job involves doing research and teaching as the Distinguished Professor of Atmospheric Science at the University of Alabama in Huntsville (UAH), has gained notoriety over the years for dissenting from mainstream climate scientists and policymakers who argue that climate change is anthropogenic, or man-made, and that something must be done to stop it.

A “working-stiff” scientist

Dissent has gained for Christy the characterization as a “climate change skeptic” or “denier,” as critics refer to him, but he himself rejects those terms.

“I’m a working-stiff atmospheric scientist,” he said, “as opposed to those who support modeling efforts, those who use data sets that other people create and analyze them, but they don’t build them themselves.”

According to Christy, the result of fewer “working-stiff” scientists contributing to the prevailing climate debate is more frequent misuses of data.

“They’re not aware of what goes into it,” Christy said, referring to the data.

“Here we have a science that’s so dominated by personalities that claim the science is settled, yet when you walk up to them and say prove it, they can’t,” he said.

Christy spoke at length about what can be proven and what cannot in his self-described “murky” field, referring often to principles of the scientific method.

You cannot prove extra greenhouse gases have done anything to the weather,” he said, responding to claims made by many scientists that more greenhouse gases have caused extreme weather patterns to intensify.

“We do not have an experiment that we can repeat and do,” he said.

Christy outlined another problem with attempts to implicate greenhouse gases: a failure to account for things countering trapping effects.

“We know that the extra greenhouse gases should warm the planet,” he said. “The weak part of that theory though is that when you add more greenhouse gases that trap heat, things happen that let it escape as well, and so not as much is trapped as climate models show.”

Economics of climate policy

Though his scientific arguments are primary, Christy also frequently discusses in interviews and testimonies the economic consequences of proposed climate change mitigation policy via carbon reduction.

“Every single person uses energy, carbon energy, and relies on carbon-based energy,” Christy said. “None of our medical advances, none of our technological advances, none of our progress would have happened in the last hundred years without energy derived from carbon.”

Christy contrasts that reality within the modern, developed world with the world he saw working as a missionary teacher in impoverished Africa during the 1970s.

“The energy source was wood chopped from the forest, the energy transmission system was the backs of women and girls hauling wood an average of three miles each day, the energy use system was burning the wood in an open fire indoors for heat and light,” Christy told members of the House Committee on Energy in 2006.

Broad availability to affordable energy enriches countries, Christy said, praising carbon.

“It is not evil. It is the stuff of life. It is plant food,” he said.

What about the fires and heat waves?

According to the National Interagency Fire Center, fires were burning in fifteen states as of Tuesday, August 14.

Alaska reported seventeen fires, Arizona reported eleven, both Oregon and Colorado reported ten, and California reported nine.

Much of the news media’s discussion about these fires over the past few weeks has established a correlation between the many fires and anthropogenic climate change, a correlation that Dr. Christy rejects.

Christy argues that exacerbating fires out west, particularly in California, results from human mismanagement. Such states have enacted strict management practices that disallow low-level fires from burning, he said.

If you don’t let the low-intensity fires burn, that fuel builds up year after year,” Christy said. “Now once a fire gets going and it gets going enough, it has so much fuel that we can’t put it out.”

“In that sense, you could say that fires today are more intense, but it’s because of human management practices, not because mother nature has done something,” Christy said.

Data from the Fire Center indicates that the number of wildfires have been decreasing since the 1970s overall, though acreage burned has increased significantly.

As for the heat, Christy said there’s nothing abnormal going on in the United States.

“Heat waves have always happened,” he said. “Our most serious heatwaves were in the 1930’s. We have not matched those at all.”

Christy continued, “It is only a perception that is being built by the media that these are dramatic worst-ever heat wave kind of things but when we look at the numbers, and all science is numbers, we find that there were periods that were hotter, hotter for longer periods in the past, so it’s very hard to say that this was influenced by human effects when you go back before there could have been human effects and there’s the same or worse kind of events.”

Though Christy didn’t deny that the last three years have been the hottest ever recorded globally, he doesn’t concede that the changes are attributable to anything other than climate’s usual and historical erraticism.

@jeremywbeaman is a contributing writer for Yellowhammer News

Ocean SSTs Lower in July

globpop_countriesThe best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

HadSST is generally regarded as the best of the global SST data sets, and so the temperature story here comes from that source, the latest version being HadSST3.  More on what distinguishes HadSST3 from other SST products at the end.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST3 starting in 2015 through July 2018

.Hadsst072018

A global cooling pattern has persisted, seen clearly in the Tropics since its peak in 2016, joined by NH and SH dropping since last August. Upward bumps occurred last October, in January and again in March and April 2018.  2018 started with slight warming after the low point of December 2017, led by steadily rising NH. Since 4/2018 SH and Tropics cooled slightly while NH pulled the Global anomaly upwards. Now in July 2018  a drop in NH with flat temps in SH and Tropics continues global cooling.

2018 is the coolest July since 2012 Globally and in NH.   The Tropics were lower in 2013.

Note that higher temps in 2015 and 2016 were first of all due to a sharp rise in Tropical SST, beginning in March 2015, peaking in January 2016, and steadily declining back below its beginning level. Secondly, the Northern Hemisphere added three bumps on the shoulders of Tropical warming, with peaks in August of each year.  Also, note that the global release of heat was not dramatic, due to the Southern Hemisphere offsetting the Northern one.

With ocean temps positioned lower than July three years ago, further cooling appears likely. As the analysis below shows, the North Atlantic has been the wild card bringing warming this decade, and cooling will depend upon a phase shift in that region.  2018 NH July peak is almost 0.4C lower than NH peak in 2015.

A longer view of SSTs

The graph below  is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July.

Hadsst95to072018

Open image in new tab to enlarge.

1995 is a reasonable starting point prior to the first El Nino.  The sharp Tropical rise peaking in 1998 is dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99.  For the next 2 years, the Tropics stayed down, and the world’s oceans held steady around 0.2C above 1961 to 1990 average.

Then comes a steady rise over two years to a lesser peak Jan. 2003, but again uniformly pulling all oceans up around 0.4C.  Something changes at this point, with more hemispheric divergence than before. Over the 4 years until Jan 2007, the Tropics go through ups and downs, NH a series of ups and SH mostly downs.  As a result the Global average fluctuates around that same 0.4C, which also turns out to be the average for the entire record since 1995.

2007 stands out with a sharp drop in temperatures so that Jan.08 matches the low in Jan. ’99, but starting from a lower high. The oceans all decline as well, until temps build peaking in 2010.

Now again a different pattern appears.  The Tropics cool sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16, with July 2017 only slightly lower.  Note also that starting in 2014 SH plays a moderating role, offsetting the NH warming pulses. (Note: these are high anomalies on top of the highest absolute temps in the NH.)

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

But the peaks coming nearly every summer in HadSST require a different picture.  Let’s look at July in the North Atlantic from the Kaplan dataset.
amo-july-20181

The AMO Index is from from Kaplan SST v2, the unaltered and untrended dataset. By definition, the data are monthly average SSTs interpolated to a 5×5 grid over the North Atlantic basically 0 to 70N. The graph shows warming began after 1992 up to 1998, with a series of matching years since. Because the N. Atlantic has partnered with the Pacific ENSO recently, let’s take a closer look at some AMO years in the last 2 decades.

amo-decade-0720181

This graph shows monthly AMO temps for some important years. The Peak years were 1998, 2010 and 2016, with the latter emphasized as the most recent. The other years show lesser warming, with 2007 emphasized as the coolest in the last 20 years. Note the red 2018 line is at the bottom of all these tracks. Most recently July 2018 is 0.4C lower than July 2016, and is the coolest July since 2002.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up?  If the pattern of lower SSTs in July is any indication, climate change of the cooling variety is looking more likely

Postscript:

In the most recent GWPF 2017 State of the Climate report, Dr. Humlum made this observation:

“It is instructive to consider the variation of the annual change rate of atmospheric CO2 together with the annual change rates for the global air temperature and global sea surface temperature (Figure 16). All three change rates clearly vary in concert, but with sea surface temperature rates leading the global temperature rates by a few months and atmospheric CO2 rates lagging 11–12 months behind the sea surface temperature rates.”

Footnote: Why Rely on HadSST3

HadSST3 is distinguished from other SST products because HadCRU (Hadley Climatic Research Unit) does not engage in SST interpolation, i.e. infilling estimated anomalies into grid cells lacking sufficient sampling in a given month. From reading the documentation and from queries to Met Office, this is their procedure.

HadSST3 imports data from gridcells containing ocean, excluding land cells. From past records, they have calculated daily and monthly average readings for each grid cell for the period 1961 to 1990. Those temperatures form the baseline from which anomalies are calculated.

In a given month, each gridcell with sufficient sampling is averaged for the month and then the baseline value for that cell and that month is subtracted, resulting in the monthly anomaly for that cell. All cells with monthly anomalies are averaged to produce global, hemispheric and tropical anomalies for the month, based on the cells in those locations. For example, Tropics averages include ocean grid cells lying between latitudes 20N and 20S.

Gridcells lacking sufficient sampling that month are left out of the averaging, and the uncertainty from such missing data is estimated. IMO that is more reasonable than inventing data to infill. And it seems that the Global Drifter Array displayed in the top image is providing more uniform coverage of the oceans than in the past.

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

 

N. Atlantic Cooling in Progress

RAPID Array measuring North Atlantic SSTs.

For the last few years, observers have been speculating about when the North Atlantic will start the next phase shift from warm to cold.

Source: Energy and Education Canada

An example is this report in May 2015 The Atlantic is entering a cool phase that will change the world’s weather by Gerald McCarthy and Evan Haigh of the RAPID Atlantic monitoring project. Excerpts in italics with my bolds.

This is known as the Atlantic Multidecadal Oscillation (AMO), and the transition between its positive and negative phases can be very rapid. For example, Atlantic temperatures declined by 0.1ºC per decade from the 1940s to the 1970s. By comparison, global surface warming is estimated at 0.5ºC per century – a rate twice as slow.

In many parts of the world, the AMO has been linked with decade-long temperature and rainfall trends. Certainly – and perhaps obviously – the mean temperature of islands downwind of the Atlantic such as Britain and Ireland show almost exactly the same temperature fluctuations as the AMO.

Atlantic oscillations are associated with the frequency of hurricanes and droughts. When the AMO is in the warm phase, there are more hurricanes in the Atlantic and droughts in the US Midwest tend to be more frequent and prolonged. In the Pacific Northwest, a positive AMO leads to more rainfall.

A negative AMO (cooler ocean) is associated with reduced rainfall in the vulnerable Sahel region of Africa. The prolonged negative AMO was associated with the infamous Ethiopian famine in the mid-1980s. In the UK it tends to mean reduced summer rainfall – the mythical “barbeque summer”.Our results show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres – the intergyre region. This a major influence on the wind patterns and the heat transferred between the atmosphere and ocean.

The observations that we do have of the Atlantic overturning circulation over the past ten years show that it is declining. As a result, we expect the AMO is moving to a negative (colder surface waters) phase. This is consistent with observations of temperature in the North Atlantic.

Cold “blobs” in North Atlantic have been reported, but they are usually a winter phenomena. For example in April 2016, the sst anomalies looked like this

But by September, the picture changed to this

And we know from Kaplan AMO dataset, that 2016 summer SSTs were right up there with 1998 and 2010 as the highest recorded.

As the graph above suggests, this body of water is also important for tropical cyclones, since warmer water provides more energy.  But those are annual averages, and I am interested in the summer pulses of warm water into the Arctic. As I have noted in my monthly HadSST3 reports, most summers since 2003 there have been warm pulses in the north atlantic.
The AMO Index is from from Kaplan SST v2, the unaltered and untrended dataset. By definition, the data are monthly average SSTs interpolated to a 5×5 grid over the North Atlantic basically 0 to 70N.  The graph shows warming began after 1992 up to 1998, with a series of matching years since.  Because McCarthy refers to hints of cooling to come in the N. Atlantic, let’s take a closer look at some AMO years in the last 2 decades.

AMO decade 072018

This graph shows monthly AMO temps for some important years. The Peak years were 1998, 2010 and 2016, with the latter emphasized as the most recent. The other years show lesser warming, with 2007 emphasized as the coolest in the last 20 years. Note the red 2018 line is at the bottom of all these tracks.  Most recently July 2018 is 0.4C lower than July 2016, and is the coolest July since 2002.

AMO July 2018

With all the talk of AMOC slowing down and a phase shift in the North Atlantic, we await SST measurements for August and September to confirm that cooling has set in.  As of July, the momentum is certainly heading downward, despite the band of warming ocean  that gave rise to now receding European heat waves.

cdas-sflux_ssta_atl_1