DTR and Rainfall

September 12, 2016

I’ve been looking at DTR and rainfall relationships for Northern and Southern Australia.  I’ve also analysed them by winter and summer (southern and northern wet seasons).

I’ve used a different approach.  Instead of comparing DTR with rainfall anomalies (differences from the mean) I’ve converted these to percentage differences from the mean rainfall.

Data are from the BOM climate change page, so DTR is based on Acorn.  DTR before 1950, and especially before 1932, may be suspect.  However the data are useful for this comparison.

Propositions to test:

DTR which is supposed to decrease as a fingerprint of greenhouse warming, is strongly related to rainfall variation.

There is an unexplained increase in DTR around 2001.

In the time series plots below, rainfall has been inverted, so ‘up’ is dry and ‘down’ is wet.  The rainfall anomalies are expressed as percentages difference from the mean and scaled down by 50.

dtr-rain-oz-ann

dtr-vs-rain-oz-ann

dtr-rain-n-oz-ann

dtr-vs-rain-n-oz-ann

dtr-rain-s-oz-ann

dtr-vs-rain-s-oz-ann

Now comparisons during northern wet season (November to April, basically summer), and southern wet season (May to October- winter and spring).

dtr-rain-oz-summ

dtr-vs-rain-oz-summ

dtr-rain-oz-wint

dtr-vs-rain-oz-wint

dtr-rain-n-oz-summ

dtr-vs-rain-n-oz-summ

dtr-rain-n-oz-wint

dtr-vs-rain-n-oz-wint

dtr-rain-s-oz-summ

dtr-vs-rain-s-oz-summ

dtr-rain-s-oz-wint

dtr-vs-rain-s-oz-wint

Results:

table

 

 

 

 

 

 

Notice that Southern Australian winters dominate DTR.  The impact of rainfall on DTR in Southern Australian winters is twice that in Northern Australian winters, and correlates better as well.  Also note that Southern summers have very slightly higher DTR change per rainfall change and slightly better correlation than Northern.  No doubt you realise winters up here can’t really be compared with southern winters, being mild and very dry.  In many places it is not very difficult to double the mean rainfall in winter with not many millimetres of rain, and zero rain for many months in winter is not unusual.

This plot shows Cusums of DTR and inverted, scaled rainfall.

cusums

The turning points line up exactly, including 2001.  There is no visible unusual change in 2001.  There are however times when the Cusums diverge: 1932, 1958, 1985, and 2003 and 2011.

DTR is strongly related to rainfall variation, especially in southern Australia in winter.

There is no unexplained increase in DTR in 2001.

 

The Pause Update: August 2016

September 12, 2016

The complete UAH v6.0 data for August were released on yesterday. I present all the graphs for various regions, and as well summaries for easier comparison. The Pause has finally ended globally and for the Northern hemisphere, but still refuses to go away in the Southern Hemisphere.

These graphs show the furthest back one can go to show a zero or negative trend (less than 0.1 +/-0.1C per 100 years) in lower tropospheric temperatures. I calculate 12 month running means to remove the small possibility of seasonal autocorrelation in the monthly anomalies. Note: The satellite record commences in December 1978- now 37 years and 9 months long- 453 months. 12 month running means commence in November 1979. The y-axes in the graphs below are at December 1978, so the vertical gridlines denote Decembers. The final plotted points are August 2016.

[CLICK ON IMAGES TO ENLARGE]

Globe:

pause-aug-16-globe

The Pause has ended. A trend of +0.13C/100 years (+/- 0.1C) since March 1998 must make GWEs tremble with joy.

And, for the special benefit of those who think that I am deliberately fudging data by using 12 month running means, here is the plot of monthly anomalies:
pause-aug-16-globe-monthly

Still +0.33C/100 years since December 1997- not exactly alarming. The Pause will return sooner with monthly anomalies than 12 month means of course.

Northern Hemisphere:

pause-aug-16-nh

The Northern Hemisphere Pause has ended. Note the not very alarming warming of 0.33C +/- 0.1C per 100 years for half the record compared with 1.39C for the whole period.

Southern Hemisphere:

pause-aug-16-sh

For well over half the record, the Southern Hemisphere has zero trend.

Tropics:

pause-aug-16-tropics

The Pause has shortened again with the El Nino influence, but is still over half the record. However, don’t be surprised if the Pause disappears next month.

Tropical Oceans:

pause-aug-16-tropic-oceans

The Pause has shortened by another 3 months- the El Nino now having a strong effect on the 12 month means.

Northern Extra Tropics:

pause-aug-16-nh-extt

The Pause by this criterion has ended in this region, however note that the slope since 1998 is +0.39 +/- 0.1C per 100 years compared with +1.61C for the whole period- a quarter of the rate.

Southern Extra Tropics:

pause-aug-16-sh-extt

No change.

Northern Polar:

pause-aug-16-np

The Pause has ended in this region. (No cause for celebration- we definitely would not want to see cooling here!)

Southern Polar:

pause-aug-16-sp

The South Polar region has been cooling for the entire record- 36 years 10 months.

USA 49 States:

pause-aug-16-usa49

No change in length of the Pause.

Australia:

pause-aug-16-oz

No change here either.

The next graphs summarise the above plots. First, a graph of the relative length of The Pause in the various regions:

pause-length-aug-16

Note that the Pause has ended by my criteria in all regions of Northern Hemisphere, and consequently the Globe, but the Tropics and all southern regions have a Pause for over half the record, including the South Polar region which has been cooling for the whole record.

The variation in the linear trend for the whole record, 1978 to the present:

trends-78-to-now

Note the decrease in trends from North Polar to South Polar.

And the variation in the linear trend since June 1998, which is about halfway between the global low point of December 1997 and the peak in December 1998:

trends-98-to-now

The only region to show strong warming for this period (18 years 3 months) is the North Polar region: the Northern Extra Tropics, Tropics, the Northern Hemisphere, and the Globe have mild warming but all other regions (including all of the Southern Hemisphere) are Paused or cooling. The imbalance between the two hemispheres is obvious. The lower troposphere over Australia has been strongly cooling for more than 18 years- just shy of half the record.

The next few months will be interesting. The Pause should disappear from the Tropics next month and the Southern Hemisphere should follow. How long will the Pause last in the Southern Extra Tropics and South Polar regions?

The Pause Update: July 2016

August 7, 2016

The complete UAH v6.0 data for July were released on Friday.  I present all the graphs for various regions, and as well summaries for easier comparison.  The Pause still refuses to go away, despite all expectations.

These graphs show the furthest back one can go to show a zero or negative trend (less than 0.1 +/-0.1C per 100 years) in lower tropospheric temperatures. I calculate 12 month running means to remove the small possibility of seasonal autocorrelation in the monthly anomalies. Note: The satellite record commences in December 1978- now 37 years and 8 months long- 452 months. 12 month running means commence in November 1979. The y-axes in the graphs below are at December 1978, so the vertical gridlines denote Decembers. The final plotted points are July 2016.

 [CLICK ON IMAGES TO ENLARGE]

Globe:

Pause july 16 globe

The Pause is 3 months shorter.

And, for the special benefit of those who think that I am deliberately fudging data by using 12 month running means, here is the plot of monthly anomalies, which shows that The Pause is over by my rather strict criterion:

Pause july 16 globe monthly

+0.33C/100 years since December 1997- not exactly alarming.  The Pause will return sooner with monthly anomalies than 12 month means of course.

Northern Hemisphere:

 

Pause july 16 nh

The Northern Hemisphere Pause has ended as expected.  Note the not very alarming warming of 0.28 +/- 0.1C per 100 years for half the record compared with 1.38C for the whole period.

Southern Hemisphere:

Pause july 16 sh

The Pause has shortened by another 4 months, but still, for well over half the record, the Southern Hemisphere has zero trend.

Tropics:

Pause july 16 tropics

The Pause has shortened by another 2 months with the El Nino influence, but is still over half the record.

Tropical Oceans:

Pause july 16 tropic ocean

The Pause has shortened by another 3 months- the El Nino now having a strong effect on the 12 month means.

Northern Extra Tropics:

Pause july 16 NH Ext tropics

The Pause by this criterion has ended in this region, however note that the slope since 1998 is +0.34 +/- 0.1C per 100 years compared with +1.6C for the whole period.  That’s still embarassingly slow warming.

Southern Extra Tropics:

Pause july 16 SH Ext tropics

The Pause has lengthened again by another month.

Northern Polar:

Pause july 16 NP

The Pause has decreased by 1 month.

Southern Polar:

Pause july 16 SP

The South Polar region has been cooling for the entire record- 36 years 9 months.

USA 49 States:

Pause july 16 USA

The Pause is 2 months shorter.

Australia:

Pause july 16 Oz

The Australian Pause is one month longer.

The next graphs summarise the above plots. First, a graph of the relative length of The Pause in the various regions:

Pause length jul16

Note that the Pause has ended by my criteria in the Northern Extra Tropics and the Northern Hemisphere, but apart from the North Polar region, all other regions have a Pause for over half the record, including the South Polar region which has been cooling for the whole record.

The variation in the linear trend for the whole record, 1978 to the present:

Trends 1978 july 16

Note the decrease in trends from North Polar to South Polar.

And the variation in the linear trend since June 1998, which is about halfway between the global low point of December 1997 and the peak in December 1998:

Trends 1998 july 16

The only region to show strong warming for this period (18 years 2 months) is the North Polar region: the Northern Extra Tropics, Tropics, the Northern Hemisphere, and the Globe have very mild warming but all other regions (including all of the Southern Hemisphere) are Paused or cooling. The imbalance between the two hemispheres is obvious. The lower troposphere over Australia has been strongly cooling for more than 18 years- just shy of half the record.

And finally, here is a plot of Global UAH versus CO2 concentration at Cape Grim from January 1996 to June 2016:

UAH vs C Grim co2 to 1996 June 2016

Now that’s a Pause!

Interim Pause Update: July 2016

August 2, 2016

This is a brief initial post with the UAH data for July 2016 with Global, Northern Hemisphere, Southern Hemisphere, and Tropical data only, which were released this morning.  I will post all graphs when the full dataset is available in about one week’s time.

Globe:

Pause july 16 globe

The Pause is hanging on but the trend will probably go above +0.1C per 100 years next month.

Northern Hemisphere:

Pause july 16 nh

The Pause is over, but the trend for the past 18 years and 3 months is +0.28C, which is about one fifth of the trend for the whole satellite period.

Southern Hemisphere:

Pause july 16 sh

The Pause has shortened by 4 months to 20 years and 2 months.

Tropics:

Pause july 16 tropics

The Pause has decreased to 19 years 1 month.

All graphs will be available shortly.

Temperature Variation Due to ENSO

July 25, 2016

In this post I use the Multivariate ENSO Index (MEI) supplied by NOAA at http://www.esrl.noaa.gov/psd/enso/mei/index.html and lower tropospheric temperature data supplied by UAH to show how much of temperature variation over the past 20 years is due to ENSO and how little is due to CO2.  I will keep words brief and let graphics do the talking.

Firstly, here is the MEI data from 1950:

Fig. 1:  Monthly MEI from 1950

mei monthly

As an aside, this is how it compares with SOI data.  The SOI is inverted and both are scaled for comparison.

Fig. 2:  MEI compared with SOI inverted

mei vs soi

Now compare scaled MEI with Global UAH:

Fig. 3: MEI (scaled) and UAH

mei monthly w uah

Notice tropospheric temperatures appear to lag the MEI by some 5 months:

Fig. 4: MEI advanced 5 months and UAH

mei monthly advd 5m w uah graph

Notice both datasets are noisy, and there is a clear discrepancy in the early 1990s.  12 month running means show this more clearly:

Fig. 5:  12 month means of UAH and MEI advanced 5 months:

mei advd w uah 12m

The slump in UAH data is shown by the arrow.  Mt Pinatubo’s main eruption was in June 1991. (Without El Chichon in 1982, there may well have been a much higher spike in the mid-1980s).

Now let’s look at the correlation between monthly MEI and UAH.  Firstly, the whole period from December 1978:

Fig. 6:  UAH vs MEI advanced 5 months 1978 – 2016

mei monthly advd 5m w uah

About 13% of temperature variation is associated with MEI variation.  Doesn’t tell us much does it.  What if we exclude the UAH data for two years from April 1982, and from July 1991 to December 1995?

Fig. 7:  UAH vs MEI advanced 5 months 1978 – 2016 with periods after volcanic eruptions excluded

mei monthly advd 5m v uah excl volcanoes

Considering the fluctuations in both datasets, that shows a fairly strong correlation.

Next, we examine the periods, before, during, and after the Pinatubo influence.

Fig. 8:  :  UAH vs MEI advanced 5 months December 1978 – June 1991, excluding April 1982 to March 1984

mei monthly advd 5m w uah 78-91

Again we see a similar correlation.

Fig. 9:  UAH vs MEI advanced 5 months July 1991 – December 1995

mei monthly advd 5m w uah 91-95.jpg

The strong positive correlation of the previous plots has broken down.

Fig. 10:  UAH vs MEI advanced 5 months January 1996 – June 2016

mei monthly advd 5m w uah 96-16

The correlation is even higher.  Over half of temperature variation is associated with ENSO variation five months previously.  Here is the same 1996-2016 plot but with 12 month running means:

Fig. 11  UAH vs MEI advanced 5 months January 1996 – June 2016, with 12 month running means

mei  advd 5m w uah 96-16 12m

74% of temperature variation for the past 20 years and 6 months can be explained by previous ENSO variation alone.  In the same period, carbon dioxide concentration at Mauna Loa has increased by 44.77 ppm, which is more than 49% of the entire increase from 1958, and Global temperature as measured by UAH has increased by a little over 0.1 degree C.

No wonder Global Warming Enthusiasts were pinning their hopes on the 2015-16 El Nino to put an end to the Pause, but they must also hope for the ENSO- temperature correlation to break down shortly, as a deep La Nina will mean cooler temperatures and further embarrassment for them.  However, the correlation breaks down when volcanoes cause lower temperatures in El Nino conditions as we have seen, but what mechanism could there be for higher temperatures in La Nina conditions?  Perhaps that magical greenhouse gas CO2?  That would indeed be spectacular- there are no outliers at the low end of any of the above plots.  The most UAH has been higher than expected with low MEI is about +0.2C to +0.3C, and those values cannot be described as outliers.  Besides, UAH for June is already down to +0.34C, and we are only four months past the peak- the cooling has barely begun.

Finally, this is a plot of the centred 37 month mean MEI (because La Ninas can last for three years).

Fig. 12: 37 month centred mean MEI

mei 37m avg

Notice that before 1975 the 37 month average never exceeded +0.5, the majority of the time was in negative territory, and in the 1950s and 1970s reached below -1.0.  Since 1975 the MEI has dropped below -0.5 only once in 2000 and approached -0.5 in 2012, but has been in positive territory for the vast majority of the time, exceeded +0.5 in six events, and was above +1.0 in the early 1990s.  It would be surprising if global temperatures had not seen a large increase.

How low will the monthly MEI go with the coming La Nina, and how low will the following global temperatures go?  All depends on La Nina’s length and strength, but the monthly MEI data are falling fast.  Stand by.

The Pause Update: June 2016

July 8, 2016

The complete UAH v6.0 data for June were released yesterday.  I present all the graphs for various regions, and as well summaries for easier comparison.  The Pause still refuses to go away, despite all expectations.

These graphs show the furthest back one can go to show a zero or negative trend (less than 0.1 +/-0.1C per 100 years) in lower tropospheric temperatures. I calculate 12 month running means to remove the small possibility of seasonal autocorrelation in the monthly anomalies. Note: The satellite record commences in December 1978- now 37 years and 7 months long- 451 months. 12 month running means commence in November 1979. The y-axes in the graphs below are at December 1978, so the vertical gridlines denote Decembers. The final plotted points are June 2016.

 [CLICK ON IMAGES TO ENLARGE]

Globe:

pause jun16 globe

The 12 month mean to June 2016 remains at +0.46C and should stay at about this value for the next two months.  If so, The Pause, (now 1 month shorter), will continue to be an embarrassing reality! However, it may end soon after with a small positive trend.

And, for the special benefit of those who think that I am deliberately fudging data by using 12 month running means, here is the plot of monthly anomalies, which shows that The Pause is over by my rather strict criterion:

pause jun16 globe mthly

+0.3C/100 years since December 1997- not exactly alarming.  The Pause will return sooner with monthly anomalies than 12 month means of course.

Northern Hemisphere:

pause jun16 NH

The Northern Hemisphere Pause has ended as expected.  Note the not very alarming warming of 0.21 +/- 0.1C per 100 years for half the record compared with 1.37C for the whole period.

Southern Hemisphere:

pause jun16 SH

The Pause has shortened by 2 months.  For well over half the record the Southern Hemisphere has zero trend.

Tropics:

pause jun16 tropics

The Pause has shortened by another 3 months with the El Nino influence, but is still over half the record.

Tropical Oceans:

pause jun16 tropic oceans

The Pause has shortened by another 2 years- the El Nino now having a strong effect on the 12 month means.

Northern Extra Tropics:

pause jun16 NH ExtT

The Pause by this criterion has ended in this region, however note that the slope since 1998 is +0.29 +/- 0.1C per 100 years compared with +1.59C for the whole period.  That’s still embarassingly slow warming.

Southern Extra Tropics:

pause jun16 SH ExtT

The Pause has lengthened by another month.

Northern Polar:

pause jun16 NP

The Pause has decreased by 1 month.

Southern Polar:

pause jun16 SP

The South Polar region has been cooling for the entire record.

USA 49 States:

pause jun16 USA49

No change.

Australia:

pause jun16 Oz

The Australian Pause has not changed.

The next graphs summarise the above plots. First, a graph of the relative length of The Pause in the various regions:

Pause length jun 16

Note that the Pause has ended by my criteria in the Northern Extra Tropics and the Northern Hemisphere, but apart from the North Polar region, all other regions have a Pause of 18 years 8 months or longer- well over half the record, including the South Polar region which has been cooling for the whole record.

The variation in the linear trend for the whole record, 1978 to the present:

Trends 1978 jun 16

Note the decrease in trends from North Polar to South Polar.

And the variation in the linear trend since June 1998, which is about halfway between the global low point of December 1997 and the peak in December 1998:

Trends 1998 jun 16

The only region to show strong warming for this period (18 years 1 month) is the North Polar region: the Northern Extra Tropics, Tropics, and the Northern Hemisphere have very mild warming but all other regions (including the Globe as a whole and all of the Southern Hemisphere) are Paused or cooling. The imbalance between the two hemispheres is obvious. The lower troposphere over Australia has been strongly cooling for more than 18 years.

12 month means will continue to grow in some regions for the next few months, so the Pause as here defined may end in some regions shortly (probably North Polar, Tropics, and Tropical Oceans), and may not reappear until early 2018.  The impact of the coming La Nina will be worth watching.  Unless temperatures reset at a new, higher level and continue rising, very low trends will remain.

“Well mixed” Carbon Dioxide Part 2: Sources and Sinks

June 26, 2016

Following from Part 1 (North vs South), this post looks at current sources and sinks for CO2.

Here are some images of surface CO2 concentration for today (June 26 in Australia) from nullschool.

Darker areas show lower CO2, lighter areas are higher.  I recommend the nullschool site!

Europe:

Europe

The industrialised Ruhr valley appears to have the highest CO2 concentration.  Paris Berlin and London are difficult to identify however.

South America (Argentina):

Buenos Aires

The high concentration appears to be from Buenos Aires- perhaps the satellite image of the CO2 is 200 km off target?

China, Korea, and Japan:

China Korea Japan

The highest concentration appears to be close to Japan’s larger cities.  Eastern China, including Shanghai and Beijing, is around 402ppm.

Southern Africa:

S Africa

Kinshasa and Johannesburg are close to the high concentrations, but dry season fires could also be the cause.

Indochina:

Indochina

Oddly, the high concentration is to the south west and west of Hanoi in a rural region.

USA:

USA

A large part of the USA seems to be one vast carbon sink at the moment.  New York and Chicago areas could be associated with some higher CO2, and there are those two areas in California, one of which I identified as Los Angeles in the previous post.  Now I’m not so sure.  More later.

Kamchatka yesterday:

high co2 kamchatchka peninsula

And today:

kamchatchka peninsula 26 june

The Kamchatka Peninsula features many active volcanoes and that’s what I think we are seeing here.  Yesterday afternoon the concentration peaked at 509ppm and today is down a lot but the “hot spots” are still distinct.

Australia:

Australia

Again inland eastern Australia is a carbon sink with large areas under 390ppm.  Melbourne may be the cause of a 408ppm area, but where is Sydney? Brisbane? Perth? Adelaide?

Southern California:

California

Note San Francisco does not appear to have over high CO2.  One of the high areas is indeed over the Los Angeles area, but the other is in the mountains to the north:  Kern County to be precise, where a bushfire has broken out.  The other ‘haze’ appears to be from the Santa Barbara fire.  See this map of fire locations.

firemap usa

It seems to me that it is hard to identify strong sources of CO2 associated with the world’s large cities and industrial areas.  However, it is the weekend, so perhaps this will change during the coming week.  We shall see.

On the other hand, very strong sources of CO2 can be traced to volcanoes and bushfires, and also decaying vegetation in the dry season.  Sinks as we have seen are clearly associated with rapidly growing crops, grasslands, and forests.

And today the Equatorial Pacific sink appears to match the cooler water being pushed westwards by the strengthening trade winds.  See for yourself at nullschool.

I will continue to monitor these sources and sinks as the seasons progress.

“Well Mixed” Carbon Dioxide Part 1: North vs South

June 24, 2016

This post addresses the question: How “well mixed” is carbon dioxide in Earth’s atmosphere?

Here are some images of surface CO2 concentration for yesterday (June 23 in Australia) from nullschool.

Darker areas show lower CO2, lighter areas are higher.  Very nifty.

Fig. 1:  Northern Hemisphere CO2:

co2 image NH

The dark areas with low CO2 are the northern forests and farm land, now growing strongly.  Note the cold, dry North Pole has high CO2.

Fig. 2: Southern Hemisphere:

co2 image SH

Cold, dry Antarctica has high CO2, whereas a broad area of inland Eastern Australia, which recently has had some decent rain, has lower CO2.

Fig. 3:The East:

co2 image EH

Fig. 4: The West:

co2 image WH

The contrast in South America is interesting!

Fig. 5:  The Pacific (a hemisphere on its own):

co2 image Pacific

Note the northern Pacific (north of 5 degrees north) is predominantly above 400ppm, while a broad band from about 5 degrees north to about 20 degrees south is about 395ppm.

Note also a tiny area in southern California pluming into the Pacific with a very high reading of 437ppm.  Los Angeles.

The IPCC and climate scientists generally refer to data from Mauna Loa in Hawaii.  The CSIRO in Australia also measures CO2 concentration at Cape Grim in Tasmania.  The next few charts compare Cape Grim data with that of Mauna Loa.

Fig. 6:  Comparison Mauna Loa and Cape Grim CO2 1976-2016

ML v CG co2

Here is a closer look at the most recent years:

Fig. 7:  Comparison Mauna Loa and Cape Grim CO2 2010-2016

ML v CG co2 2010-16

There are several points to note:

Cape Grim CO2 concentration is increasing at the same rate as Mauna Loa.

There are massive swings in Mauna Loa’s data, while Cape Grim fluctuates gently.  In 2016 there was no “bottom” at all.

Cape Grim is much lower- in fact the annual high points are at about the same level as Mauna Loa’s low points.

The records are out of phase.  Mauna Loa peaks in northern spring and bottoms out in northern autumn, whereas Cape Grim peaks in southern Spring and “bottoms out” in southern Summer.

Now I look at the seasonal change in concentration.

Fig. 8:  Seasonal rises and falls at Cape Grim

Inc decr CG

Fig. 9:  Seasonal rises and falls at Mauna Loa

Inc decr ML

Notice at Mauna Loa the annual rises from bottoms to peaks are getting larger, but so are the falls, while at Cape Grim there are slower rises but falls are lessening.  I compare rises and falls separately in the next two plots:

Fig. 10:  Seasonal increases compared

Incr ML v CG

Fig. 11:  Seasonal decreases compared

Decr ML v CG

I would interpret this as follows:

As emissions increase, carbon dioxide sinks (mainly growing plants) consume more and more.  However this is not enough to remove all of the additional CO2, so each year the growth continues.

In the Northern Hemisphere, sinks completely overwhelm sources in summer.

In the Southern Hemisphere there is a much less pronounced annual peak in spring, perhaps because there is less land, especially from 30 to 70 degrees south, and much of it is dry.  CO2 concentration has increased to the level at which vegetation CO2 sinks are becoming unable to make an impression (at least in El Nino years).

The bulk of CO2 increase originates in the Northern Hemisphere.  In northern winter as the Inter-Tropical Convergence Zone shifts south of the Equator, the north east trade winds move CO2 to the Southern Hemisphere where it is gradually mixed.  In northern summer (now), the ITCZ is north of the Equator, and the image of the Pacific in Figure 5 above shows trade winds crossing the Equator with less CO2 concentration than just to the north.

We know there are large changes to CO2 concentration following ENSO events.  This may be due to the changing circulation over the tropical Pacific as more or less CO2 is shifted by trade winds north and south. Or perhaps changing ocean currents, upwelling, or downwelling warm or cool large ocean areas.

Drier areas of the globe (deserts, Polar regions) have higher CO2 concentration than wetter areas.  Few growing plants, more CO2.  More and greener plants, less CO2.

And finally: CO2 is not “well mixed” globally, and an average concentration is as elusive as an average temperature.  There is a range of concentrations between areas of sources and sinks approaching 80ppm.

The Pause Update: May 2016

June 5, 2016

The complete UAH v6.0 data for May were released on today.  I present all the graphs for various regions, and as well summaries for easier comparison.  The Pause still refuses to go away, despite all expectations.

These graphs show the furthest back one can go to show a zero or negative trend (less than 0.1 +/-0.1C per 100 years) in lower tropospheric temperatures. I calculate 12 month running means to remove the small possibility of seasonal autocorrelation in the monthly anomalies. Note: The satellite record commences in December 1978- now 37 years and 6 months long- 450 months. 12 month running means commence in November 1979. The y-axes in the graphs below are at December 1978, so the vertical gridlines denote Decembers. The final plotted points are May 2016.

 [CLICK ON IMAGES TO ENLARGE]

Globe:

May16 globe

The 12 month mean to May 2016 is +0.46C.  The Pause is still an embarrassing reality! However, it may “disappear” soon with a small positive trend.

And, for the special benefit of those who think that I am deliberately fudging data by using 12 month running means, here is the plot of monthly anomalies, which shows that The Pause is over by my rather strict criterion:

May16 globe mthly

+0.27C/100 years since December 1997- not exactly alarming.  The Pause will return sooner with monthly anomalies than 12 month means of course.

Northern Hemisphere:

May16 NH

The Northern Hemisphere Pause has “disappeared” as expected.  Note the not very alarming warming of 0.14+/- 0.1C per 100 years for half the record compared with 1.35C for the whole period.

Southern Hemisphere:

May16 SH

The pause has shortened by one month.  For well over half the record the Southern Hemisphere has zero trend.

Tropics:

May16 Tropics

The Pause has shortened dramatically with the El Nino influence, but is still over half the record.

Tropical Oceans:

May16 Tropic oceans

The Pause has shortened by 19 months.

Northern Extra Tropics:

May16 Nth ExTropics

The Pause by this criterion has ended in this region, however note that the slope since 1998 is +0.23 +/- 0.1C per 100 years compared with +1.58C for the whole period.  That’s still embarassingly slow warming.

Southern Extra Tropics:

May16 Sth ExTropics

The Pause has lengthened by another month.

Northern Polar:

May16 NP

The Pause has decreased by 2 months.

Southern Polar:

May16 SP

The South Polar region has been cooling for the entire record.

USA 49 States:

May16 USA49

No change.

Australia:

May16 Oz

The Australian Pause has lengthened rapidly.

The next graphs summarise the above plots. First, a graph of the relative length of The Pause in the various regions:

Pause length may16

Note that the Pause has ended by my criteria in the Northern Extra Tropics and the Northern Hemisphere, but apart from the North Polar region, all other regions have a Pause of 18 years 9 months or longer- well over half the record, including the South Polar region which has been cooling for the whole record.

The variation in the linear trend for the whole record, 1978 to the present:

Trends 1978 may16

Note the decrease in trends from North Polar to South Polar.

And the variation in the linear trend since June 1998, which is about halfway between the global low point of December 1997 and the peak in December 1998:

Trends Jun98 may16

The only region to show strong warming for this period (18 years) is the North Polar region: the Northern Extra Tropics and the Northern Hemisphere have very mild warming but all other regions are Paused or cooling. In fact “global” warming since June 1998 is limited to that part of the globe north of 20 degrees North.  And the lower troposphere over Australia has had strong cooling for the past 18 years.

12 month means will continue to grow for the next few months, so the Pause as  here defined may disappear shortly, and may not reappear until early 2018.  The impact of the coming La Nina will be worth watching.  Unless temperatures reset at a new, higher level and continue rising, very low trends will remain.

Temperature and Mortality

May 24, 2016

We are all going to die, nothing is surer. “Nobody knows the day or the hour”, but one thing is clear: we are more likely to die in winter than in summer.

Death by unnatural causes (suicide, accident, bushfire, disaster, even acute illness) can come to otherwise healthy people of any age. Death by natural causes is more predictable.

Those vulnerable to death are the elderly, very young babies, those with chronic illness (e.g. asthma, diabetes) and weakened immunity, and those with respiratory and circulatory illness.

Analysing mortality is made difficult because the sample population is always changing. Excess deaths in one month may be followed by further excess deaths in the following month, or because so many vulnerable people have already died, there will be fewer than expected deaths in the next month or months, or even the next couple of winters. Similarly, if fewer than expected deaths occur, there will be a larger cohort of the vulnerable in the following months, getting older and with probably poorer health. Population growth, aging, migration, improved vaccines, and public education programs all play a part as well.

In this analysis, I use mortality and population data from the Australian Bureau of Statistics (ABS), and temperature data from the Bureau of Meteorology (BOM), for Victoria, as it is a small and compact state which is subject to large temperature changes and also severe heat waves. Monthly mortality data are difficult to find, so this study is restricted to the period January 2002 to December 2011. A 10 year period is hardly sufficient for meaningful averages, however some useful insights can be found.

Mortality statistics are available by month, but population figures are by quarter, therefore I interpolated estimated monthly population figures based on three month growth.

Firstly, this plot shows the total deaths for every month from January 2002 to December 2011.

Fig. 1:

act D per mnth
Note the seasonal spikes and dips. The apparent increase in deaths can be compared with Victoria’s population increase:

Fig.2:

Population Vic
By dividing the total deaths by the population in thousands we can calculate the death rate:

Fig. 3:

Death rate per yr

Note the mortality rate has decreased, and that, in spite of heatwaves, bushfires, and flu pandemics, 2009 had a lower death rate than 2008.

Because months have varying numbers of days, a better analysis can be made by calculating the Daily Death Rate for each month (by dividing each monthly rate by 31, 30, 29, or 28 days).

Fig. 4:

mortality per month

For the state of Victoria for the 10 years to 2011, on average more deaths occurred for each day in August than for any other month. The lowest Daily Death Rate was in February.

Now compare with monthly averages (2002 to 2011) for maximum and minimum temperatures:

Fig. 5:

Tmax Tmin avg

The death rate peak lags July temperature by about a month. Cooler months (June to September) are deadlier than warmer (December to April).

The relationship with temperature can be shown with scatter plots:

Fig. 6:

DDR v Tmax

Fig. 7:

DDR v Tmin

Which merely reinforce that deaths are more likely in winter!

Now we look at the question of estimating how many deaths are likely in a given period, by multiplying the average daily death rate for each month by the number of days in each month and by the estimated total population for each month. By subtracting this figure from the actual number of deaths we get a mortality “anomaly”.  The following graph shows this anomaly for each year:

Fig. 8:

Act minus exp deaths per year

And each month:

Fig. 9:

Diff act minus exp Deaths per mnth

Note the peaks in the winters of 2002 and 2003, and also in the summer of 2008-2009. Note also that both graphs show that in spite of a killer heatwave, the Black Saturday bushfire, and the swine flu pandemic, deaths in 2009 were below what could be expected.

To put the anomaly for January 2009 into context, we can compare actual daily deaths per 1,000 population for all months from 2002 to 2011:

Fig. 10:

act daily D per mnth

Note that the extreme figure for January 2009, while extremely high for January, is still below those of the lowest extremes of June, July, and August.

Perhaps higher mortality in the winter months is coincidence and due to some other factor than temperature- seasonal flu incidence for example. I now look at the month of August with the highest average mortality rate:

Fig. 11:

Act minus exp deaths vs Tmin August

There is fairly decent correlation showing that for every degree warmer in minima, the August death toll will be around 150 less than expected.

February, with the lowest rate:

Fig. 12:

Act minus exp deaths vs Tmin Feb

Even in summer, warmer minima mean fewer deaths.

In summer, do higher maxima cause more deaths?

Fig. 13:

Act minus exp deaths vs Tmax Feb

Even including the 173 deaths in the Black Saturday bushfires in the 200 extra deaths for February 2009, there is no trend.

January, whose data include the 2009 heatwave:

Fig. 14:

Act minus exp deaths vs Tmax Jan

A very small trend, but the 2009 heatwave outlier is obvious and skews the data. (Victorian health authorities say there were 374 excess deaths in the week to 1 February 2009).

Extreme heatwaves are indeed killers. Normal hot summers up to two degrees above average are not.

Conclusion:

Improved public health measures, influenza vaccines, and improved public awareness – plus warmer winters- have led to a decrease in the Victorian mortality rate in the period 2002-2011.

Extreme heatwaves are dangerous in Victoria and cause hundreds of extra deaths especially amongst the elderly (>75 years old). However, these are rare events. Severe and Extreme Heatwaves are newsworthy precisely because they are unusual.

Normal Victorian winters are even more dangerous with on average 17.5% more deaths in winter than summer every year, but because this is normal and expected, this regular annual spike in deaths is unremarkable and not newsworthy- much less regarded as a natural disaster. While 374 excess deaths in a week in a heatwave is shocking, even with these included, the highest January’s Daily Death Rate (in 2009) is below that of the lowest of any winter month.

Warmer minimum temperatures are associated with lower death rates at all times of the year, but especially in August in Victoria, where for every degree of extra warmth, about 150 fewer deaths can be expected. I hope, for the sake of those who are sick or elderly, that we have a warm winter this year.