The Pause Update: February 2017

March 4, 2017

The complete UAH v6.0 data for February have been released. I present all the graphs for various regions, and as well summaries for easier comparison. I also include graphs for the North and South Temperate regions (20-60 North and South), estimated from Polar and Extra-Tropical data.

The Pause has ended globally and for all regions including the USA and the Southern Hemisphere, except for Southern Extra-Tropics, South Temperate, South Polar, and Australia. The 12 month mean to February 2017 for the Globe is +0.44 C.

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 38 years and three months long- 459 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 February 2017.
[CLICK ON IMAGES TO ENLARGE]

Globe:

feb-17-globe

The Pause has ended. A trend of +0.39 C/100 years (+/- 0.1C) since March 1998 is creeping up, but the 12 month means have peaked and are heading down.

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:

feb-17-globe-monthly

Northern Hemisphere:

feb-17-nh

The Northern Hemisphere Pause has well and truly ended.

Southern Hemisphere:

feb-17-sh

The Pause has ended- just.

Tropics:

feb-17-tropics

The Pause in the Tropics (20N to 20S) has ended and the minimal trend is now +0.4C/ 100 years. 12 month means are dropping fast.

Northern Extra Tropics:

feb-17-next

Northern Temperate Region:

feb-17-n-temp

Using estimates calculated from North Polar and Northern Extra-Tropics data, the slowdown is obvious.

Southern Extra Tropics:

feb-17-sext

The Pause has weakened and may soon disappear.

Southern Temperate Region:

feb-17-s-temp

Using estimates calculated from South Polar and Southern Extra-Tropics data, the Pause is shorter than for Southern Extra-Tropics.

Northern Polar:

feb-17-np

The trend has increased rapidly and will continue to do so even though 12 month means have started to fall.

Southern Polar:

feb-17-sp

The South Polar region has been cooling (-0.2C) for the entire record. With 12 month means still rising, this cooling trend will slow over the next few months.

USA 49 States:

feb-17-usa49

The Pause has ended. It will not re-appear for some time.

Australia:

feb-17-oz

The Pause is still 21 years 5 months.

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

feb-17-pause-length

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

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

feb-17-trends-78

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:

feb-17-trends-98

The imbalance between the two hemispheres is obvious. The lower troposphere over Australia has been strongly cooling for 18 years and 9 months- just shy of half the record.
The Pause has disappeared from the USA and the Southern Hemisphere, but not the Southern Extra-Tropics, South Temperate, and South Polar regions, or Australia. El Nino tropical heat is rapidly decreasing, with all northern means falling, but will continue to affect the Southern Hemisphere in coming months.  Global TLT anomalies have increased a little.   The next few months will be interesting.

 

 

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How Temperature Is “Measured” in Australia: Part 1

March 1, 2017

By Ken Stewart, ably assisted by Chris Gillham, Phillip Goode, Ian Hill, Lance Pidgeon, Bill Johnston, Geoff Sherrington, Bob Fernley-Jones, and Anthony Cox.

The Bureau of Meteorology maintains the Southern Oscillation Index (SOI), one of the most useful climate and weather records in the world.  In About SOI,  the Bureau says:

 Daily or weekly values of the SOI do not convey much in the way of useful information about the current state of the climate, and accordingly the Bureau of Meteorology does not issue them. Daily values in particular can fluctuate markedly because of daily weather patterns, and should not be used for climate purposes.

It is a pity that the BOM doesn’t follow this approach with temperature, and in fact goes to the opposite extreme.

Record temperatures, maximum and minimum temperatures, and monthly, seasonal, and annual analyses are based not on daily values but on ONE SECOND VALUES.

The Bureau reports daily maximum and minimum temperatures at Climate Data Online,   but also gives a daily summary for each site in more detail on the State summary observations page , and a continuous 72 hour record of 30 minute observations (examples below), issued every 30 minutes, with the page automatically refreshed every 10 minutes, also handily graphed .  These last two pages have the previous 72 hours of readings, after which they disappear for good.  However, the State summary page, also refreshed every 10 minutes, is for the current calendar day only.

This screenshot shows part of the Queensland observations page for February 26, showing the stations in the North Tropical Coast and Tablelands district.

Fig. 1:  District summary page

mareeba-example

Note especially the High Temp of 30.5C at 01:26pm.  Clicking on the station name at the left takes us to the Latest Weather Observations for Mareeba page:

Fig. 2:  Latest Observations for Mareeba

mareeba detail example.jpg

Notice that temperature recordings are shown every 30 minutes, on the hour and half hour.

In Figure 1 I have circled the Low Temp and High Temp for Mareeba.  Except in unusual circumstances, High Temp and Low Temp values become the maximum and minimum temperatures and are listed on the Climate Data Online page, and for stations that are part of the ACORN network, become part of the official climate record.  It is most important that these High Temp and Low Temp values, the highest and lowest recorded temperatures of each day, should be accurate and trustworthy.

But frequently they are higher or lower than the half hourly observations, as in the Mareeba example (0.6C higher), and I wanted to know why.  In this post I show some recent examples, with the explanation from the Bureau.

Perhaps the difference between the Latest Weather Observations and maximum temperature reported at Climate Data Online is due to brief spikes in temperature in between the reported temperatures of the latest observations, such as in this example from Amberley RAAF on February 12.

Fig. 3:  Amberley RAAF temperatures, 12 February 2017

amberley-12-feb

A probable cause would be that the Automatic Weather Station probe is extremely sensitive to sudden changes in temperature as breezes blow warmer or cooler air around or a cloud passes over the sun.

However, this may not be the whole story.

Occasionally the report time for the High Temp or Low Temp is exactly on the hour or half hour, and therefore can be directly compared with the temperature shown for that time at the station’s page.

These progressive Low and/or High Temps on the half hour or hour occur and can be observed throughout the day at various times, as well as at the end of the reporting period.

For example, here is a mid-afternoon screenshot of the Queensland- Wide Bay and Burnett district summary for Wednesday 15th February.  I have highlighted the High Temp value for Maryborough at 1:00pm.

Fig. 4:  District summary at 2:00pm for Maryborough 15 February 2017

obs-mboro-15th

In the Latest Observations for Maryborough, I have highlighted the 1:00pm reading.

Fig. 5: Latest Observations at Maryborough at 01:00pm on 15 February

obs-mboro-15th-detail

The difference is +1.5 degrees.  Here I have graphed the results.

Fig. 6:  Maryborough 15 February

mboro-15th-graph

That’s a 1.5 degree difference at the exact same minute.

Here is a screenshot of Latest Observations values at Hervey Bay Airport on Wednesday 22 February.  Low Temp for the morning of 23.2C was reached at 6.00 a.m.

Fig. 7:  Hervey Bay, 06:00am  22 February 2017

hervey-bay-22nd

Note that at 6.00am, just after sunrise, the Latest Observations page shows that the temperature was 25.3 degrees.  The daily Low Temp was reported as 23.2 degrees at 6.00am – 2.1 degrees cooler.  This graph will show the discrepancy more plainly.

Fig. 8:  Hervey Bay temperatures 22 February

hervey-bay-22nd-graph

What possible influence would cause a dawn temperature to drop 2.1 degrees?

I sent a query to the Bureau about Hervey Bay, and the explanation from the Bureau’s officer was enlightening:

Firstly, we receive AWS data every minute. There are 3 temperature values:
1. Most recent one second measurement
2. Highest one second measurement (for the previous 60 secs)
3. Lowest one second measurement (for the previous 60 secs)

Relating this to the 30 minute observations page: For an observation taken at 0600, the values are for the one minute 0559-0600.

I’ve looked at the data for Hervey Bay at 0600 on the 22nd February.
25.3, 25.4, 23.2 .

The temperature reported each half hour on the station Latest Observations page is the instantaneous temperature at that exact second, in this case 06:00:00, and the High Temp or Low Temp for the day is the highest or lowest one second temperature out of every minute for the whole day so far.  There is no filtering or averaging.

The explanation for the large discrepancy was that “Sometimes the initial heating from the sun causes cooler air closer to the ground to mix up to the temperature probe (1.2m above ground).”

However, in Figure 7 above it can be seen that the wind was south east at 17 km/hr, gusting to 26 km/hr, and had been like that all night, over flat ground at the airport, so an unmixed cooler surface layer mixing up to the probe seems very unlikely.

You will also note that the temperatures in the final second of every half hour period from 12.30 to 6.30 ranged from 25C to 25.5C, yet in some second in the final minute before 6.00 a.m. it was at 23.2C.  I have shown these values in the graph below.

Fig. 9:  Hervey Bay 05:59 to 06:00am

hervey-bay-22nd-at-6am

The orange row shows the highest temperature for this last minute at 25.4C at some unknown second, the blue row the lowest temperature for this minute (and for the morning) at 23.2C at some unknown second, and the spot temperature of 25.3C at exactly 06:00:00am.  The black lines show the upper and lower values of half hourly readings between 12:30 and 06:30: the high temp and 06:00am readings are within this range.

23.2C looks a lot like instrument error, and not subject to any filtering.

Further, there are only two possibilities:  either from a low of 23.2C, the temperature rose 2.2 degrees to 25.4C, then down to 25.3C; or else from a high of 25.4C it fell 2.2 degrees to 23.2C, then rose 2.1 degrees to 25.3C, all in the 60 seconds or less prior to 06:00:00 a.m.

How often does random instrument error affect the High and Low Temps reported at the other 526 stations?  Like Thargomindah, where on February 12 the High Temp was 2.3 degrees to 2.5 degrees higher than the temperatures 15 minutes before and after?

Fig. 10:  Thargomindah temperatures 12 February 2017

thargomindah-12-feb

Or was this due to a sudden rise and fall caused by a puff of wind, even a whirl-wind?

Who knows?  The Bureau certainly doesn’t.

 

In Part 2, I will look at patterns arising from analysis of 200 High and Low Temps occurring in the same minute as the half hourly values, and implications this has for our climate record.

The Pause Update: January 2017

February 12, 2017

The complete UAH v6.0 data for January have been released. I present all the graphs for various regions, and as well summaries for easier comparison. I also include graphs for the North and South Temperate regions (20-60 North and South), estimated from Polar and Extra-Tropical data.

The Pause has ended globally and for all regions including the USA and the Southern Hemisphere, except for Southern Extra-Tropics, South Temperate, South Polar, and Australia. The 12 month mean to January 2017 for the Globe is +0.48 C.

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 38 years and two months long- 458 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 January 2017.
[CLICK ON IMAGES TO ENLARGE]

Globe:

pause-globe-jan17

The Pause has ended. A trend of +0.36 C/100 years (+/- 0.1C) since March 1998 is creeping up, but the 12 month means have peaked and are heading down.

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-globe-jan17-monthly

That’s since December 1997.

Northern Hemisphere:

pause-nh-jan17

The Northern Hemisphere Pause has well and truly ended.

Southern Hemisphere:

pause-sh-jan17

The Pause has ended- just.

Tropics:

pause-jan17-tropics

The Pause in the Tropics (20N to 20S) has ended and the minimal trend is now +.39C/ 100 years. 12 month means are dropping fast.

As Tropical Oceans closely mimic the Tropics overall, I won’t show their plot.

Northern Extra Tropics:

pause-jan17-next

The minimal trend is up to +0.64C/ 100 years= that’s one degree less than the whole trend.

Northern Temperate Region:

pause-jan17-ntemp

Using estimates calculated from North Polar and Northern Extra-Tropics data, while the trend since June 1998 of +0.28 +/- 0.1C per 100 years is more than my criterion for a Pause, it is 1.2C less than the trend for the whole period. The slowdown is obvious, and for Land areas the trend is zero.

Southern Extra Tropics:

pause-jan17-sext

The Pause persists strongly, however 12 month means are still rising, and the Pause may shorten or even disappear.

Southern Temperate Region:

pause-jan17-stemp

Using estimates calculated from South Polar and Southern Extra-Tropics data, the Pause is shorter than for Southern Extra-Tropics.

Northern Polar:

pause-jan17-np

The trend has increased rapidly and will continue to do so even though 12 month means have started to fall.

Southern Polar:

pause-jan17-sp

The South Polar region has been cooling for the entire record. With 12 month means still rising, this cooling trend will slow over the next few months.

USA 49 States:

pause-jan17-usa49

The Pause has ended- just. It will not re-appear for some time.

Australia:

pause-jan17-oz

The Pause is still 21 years 5 months. Heat in recent weeks may push the 12 month mean higher and shorten the Pause. (September, oops!)

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

pause-length-jan17

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

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

trend-78-jan-17

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:

trend-98-jan-17

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 Pause has disappeared from the USA and Southern Hemisphere, but not the Southern Extra-Tropics, South Temperate, and South Polar regions, or Australia. El Nino tropical heat is rapidly decreasing, with all northern means falling, but will continue to affect the Southern Hemisphere in coming months.  Global TLT anomalies are now dropping rapidly. The next few months will be interesting.

Another ABC Fail

February 5, 2017

Viewers of ABC-TV news, and followers of ABC News Online, were treated to a story on Friday night about “Turtle hatchlings dying in extreme heat at Mon Repos”, as it was headlined at ABC News Online:

Piles of dead turtle hatchlings are lining Queensland’s famous Mon Repos beach amid a heatwave which has pushed the sand’s temperature to a record 75 degrees Celsius.

While the majority of hatchlings break free from their nests at night when the sand is cooler, those escaping in the day face overheating.

“They can’t sweat, they can’t pant, so they’ve got no mechanism for cooling,” Department of Environment and Heritage Protection chief scientist Dr Col Limpus said.

….

The extreme heat is also conducted down to the turtle’s nest, pushing the temperature to about 34C, which is approaching the lethal level for incubation.

That is the hottest temperature recorded in a nest in more than a decade.

A record 75 degrees sand temperature? Hottest nest temperature in more than a decade?

Time for a reality check.

I have no data on temperatures inside turtle nests, but I do have data on temperature at nearby Bundaberg Aero (Hinkler Airport), which is an ACORN site.

Using monthly Acorn data, here is a plot of all January maxima at Bundy.

bundy-jan-max

January’s mean maximum of 31.6 degrees C was equalled or exceeded in 1924, 1931, 1969, 1998, 2002, 2006, 2013, and 2014.  While monthly mean doesn’t tell us about individual days, it does give us a clue about daily temperatures in hot years.  For that I also use ACORN daily data- adjusted, homogenised, and world’s best practice apparently.

How do temperatures at this time of year compare with those of previous years?  The next figures show data for the first 45 days of every year, that is from January 1 to February 14.

bundy-jan-max-daily-45

The past three weeks at Bundaberg have been at the high end of the range, but no records have been broken, and no days have been even close to 35C.  What about previous years?  The next plot shows the number of consecutive days above 35 degrees: very likely to raise sand temperature above what it has been this year.

bundy-jan-max-daily-45-over-35

No days this year above 35C, but at least 27 occasions in previous years of single days reaching 35C, at least 6 of 2 days in a row, and one of 3 days in a row above 35C.

A 7 day running mean will show whether temperatures have been consistently high.

bundy-jan-max-7d-av-45

As you can see 2017 is high but not extreme.  2002 had a 7 day average just under 35C.

This graph plots temperatures of the first 45 days of years with similarly hot January temperatures.  2017 is the thick black line.

bundy-jan-max-daily-45-hot-yrs

On one day- January 20- 2017 was hotter than the other years.  Note how in several years the temperature drops to the mid 20s when heavy rain falls.  Note also the temperature reached the high 30s in February 2002.

The final graph shows the 7 day average of the same period of similarly hot years.

bundy-jan-max-7d-av-45-hot-yrs

Several previous periods were hotter than so far this year.

Once again we see misleading claims being made and reported by the ABC as gospel, without any attempt at fact checking.  A simple check shows that, while it may be true that the reported temperatures are the hottest recorded by these researchers, it is extremely unlikely that these were as high as they were in past years.  On every count- daily, monthly mean, 7 day mean, consecutive hot days- it can be shown that this year, while hot, is not as hot as many previously, and it follows that sand temperatures would similarly have been hotter in the past.

And that’s without considering the Holocene Optimum and the Eemian.

Another ABC fail.

Dig and Delve Part III: Temperate Regions

February 1, 2017

In this post I draw together ideas developed in previous posts- Poles Apart, Pause Updates, Dig and Delve Parts I and II– in which I lamented the lack of tropospheric data for the regions of the northern and southern hemispheres from 20 to 60 degrees North and South.  These regions between the Tropics and Polar regions I shall call Temperate regions, as that’s what I was taught in school.

A commenter of long standing, MikeR, who has always endeavoured to keep me on the straight and narrow, suggested a method of estimating temperature data for these regions using existing Polar and Extra-Tropical data.  I’ve finally got around to checking, and can now present the results.

The correct formula is:

T (20 to 60 degrees) = 1.256 x TexT ( 20 to 90 degrees) – 0.256 X T pole(60 to 90 degrees).

This gives an approximation for these regions in lieu of UAH data specifically for them.

And the results are very, very interesting.  Hello again, Pause.

All data are from the University of Alabama (Huntsville) (UAH) lower troposphere, V.6.0.

First of all, here are plots showing the Extra-Tropics (20-90), compared with  the corresponding Temperate regions (20-60).

Fig. 1:  Monthly UAH data for Northern Extra-Tropics (20-90N) and Estimate for Northern Temperate Region (20-60N)

 nth-temp-v-next

Fig. 2:  Monthly UAH data for Southern Extra-Tropics (20-90S) and Estimate for Southern Temperate Region (20-60S)

sth-temp-v-sext

As expected, the result of very slight differences is a slight cooling of the Northern Extra Tropics trend, and a slight warming for the Southern.   No surprise there.

The real surprise is in the Land and Ocean data.  In the Northern Temperate region, CuSum analysis reveals a large regime change which occurred at the beginning of 1998.  The following plots show trends in the data up to January 1998 and from February 1998 to December 2016.

Fig. 3: Estimated Northern Temperate data trends to January 1998 and from February 1998 to December 2016.

nth-temp-2-trends

Fig. 4: Estimated Northern Temperate data trends to January 1998 and from February 1998 to December 2016: Ocean areas.

nth-temp-2-trends-ocean

Fig. 5: Estimated Northern Temperate data trends to January 1998 and from February 1998 to December 2016: Land areas.

nth-temp-2-trends-land

Say hello to the Pause again.  Northern Temperate land areas- most of North America, Asia, Europe, and North Africa, containing the bulk of the world’s population, agriculture, industry, and CO2 emissions- has had zero trend for 18 years and 11 months.  While the trend for the whole record is +1.8C per 100 years, the record is clearly made of two halves, the first with a much milder +0.7C trend, then after an abrupt step change, the second half is flat- in spite of the “super El Nino” and the “hottest year ever”.

Compare this with the Extra-Tropics data, 20-90N.

Fig. 6: Northern Extra-Tropics data (20-90N) trends to January 1998 and from February 1998 to December 2016: Land areas.

next-land-2-trends

The step change is still there, but the trends are virtually unchanged- only 0.1C different +/- 0.1C.

Why the difference?  Northern Extra Tropics data (20-90N) includes the North Polar data (60-90N).  The major change in the North Polar region occurred in early 1995, as the next two figures show:

Fig. 7: Northern Polar data (60-90N) trends to February 1995 and from March 1995 to December 2016: Land areas.

np-land-2-trends

Fig. 8: Northern Polar data (60-90N) trends to February 1995 and from March 1995 to December 2016: Ocean areas.

np-ocean-2-trends

Massive changes in trend.  Note the change apparently occurred in land data before ocean, which is peculiar, and both in the dead of winter.  Polar regions, though much smaller, have a large impact on trends for the Extra-Tropics.

In the Southern part of the globe, once again say hello to the Pause.

Fig. 9: Estimated Southern Temperate data trends to January 1998 and from February 1998 to December 2016.

sth-temp-2-trends

While the step change is much smaller, using the same dates the Pause is still undeniable.

Fig. 10: Estimated Southern Temperate data trends to January 1998 and from February 1998 to December 2016- Land areas.

sth-temp-2-trends-land

Fig. 11: Estimated Southern Temperate data trends to January 1998 and from February 1998 to December 2016- Ocean areas.

sth-temp-2-trends-ocean

Most of the Southern Hemisphere is ocean, so it follows that a Pause in the ocean leads to a Pause overall.

It is important to stress that the figures I show for Northern and Southern Temperate regions are estimates, not actual data from UAH.  However, they are pretty good estimates, and until we have data from UAH, the best available.

Of the world’s regions, South Polar and Southern Temperate regions are paused, as is the Northern Temperate Land region, which is arguably the most important.  The Tropics fluctuate with ENSO.  Only the Arctic is strongly warming.

The Temperate regions are arguably the most important of the globe.  Together they cover more than half the surface area, and contain the bulk of the world’s population, agriculture, industry, and emissions.  I hope that Dr Spencer will be able to provide datasets for these regions as soon as possible.

Unprecedented South Australian Weather!

January 22, 2017

(and it has been like that for 178 years!)

There were more blackouts in South Australia a couple of days ago following a wild storm.  In a report in the Adelaide Advertiser, SA Power Networks spokesperson Paul Roberts is quoted:

“This is just another example of the unprecedented weather in the last six months,” Mr Roberts said, referring to bouts of wild weather that have hit power supplies hard this summer and the preceding spring.

21mm of rain was measured at the Kent Town gauge.

Just how “unprecedented” is Adelaide’s weather over the past few months?  I couldn’t find any records for the number of severe storms, so for a proxy I have made do with rainfall data from West Terrace and Kent Town in Adelaide.  The overlap period has very similar rainfall recordings so I joined the two series to give a record starting on 1 January 1839.  That’s 178 years of data.

When thinking about “unprecedented”, we need to check amount, intensity, and frequency.

Firstly, a few plots to give some context.  How unprecedented was Thursday’s storm?

Fig. 1: Rainfall for the first 21 days of January compared with Days 1 – 21 of every year

adelaide-rain-21-jan

Note Thursday’s rainfall had less rain than four previous occasions on this day alone, and 20 or so in previous Januarys.

Fig. 2: Rainfall for each day of 2016 compared with each day of every year:

adelaide-rain-2016

Note the December storm had extreme rain (for Adelaide) but not a record.

Amount and intensity has been higher in many previous years.  141.5mm was recorded on 7 February 1925.

Fig. 3: 7 day average rainfall over the years:

adelaide-rain-2016-7d-avg

The topmost dot shows the maximum 7 day average for each year.  2016 got to 13.4mm on 4 October- multiply by 7 to get the weekly total rain.  Note there were many wet and dry periods all through the record.

21mm of rain fell in a severe storm on Thursday, so I arbitrarily chose 20mm as my criterion for heavy rainfall in one day as a probable indicator of stormy weather.  I am the first to admit that 20mm might fall steadily all day and not be at all associated with wild winds, and wild winds can occur without any rain, but bear with me.

Fig. 4: Rain over 20mm throughout the year:

adelaide-rain-2016-above-20

There seems to be no increase in amount or intensity of rain at any time of the year.

Fig. 5: Frequency:

adelaide-rain-2016-cnt-above-20

Note 2016 had 7 days with above 20mm in 24 hours.  That’s the most since… 2000, when there were 8 days- and many previous years had 7 or 8 days, and 1889 had 9.  So no increase in frequency.

However, Mr Roberts was referring to the last six months, spring and summer.  So let’s look at rain events over 20mm from July to December, firstly amounts recorded:

Fig. 6: July to December Rain over 20mm:

adelaide-rain-above-20-last-6m

Nothing unusual about 2016.

Fig. 7:  Frequency of heavy rain July – December:

adelaide-rain-2016-cnt-above-20-last-6m

1973, 1978, and 1992 had the same or more days with over 20mm.

I now restrict the count to spring and summer only:

Fig. 8:  Spring and Summer frequency:

adelaide-rain-2016-cnt-above-20-last-4m

Not unprecedented: 1992 had one more.  Add in last Thursday’s event to make them equal.

Conclusion

Adelaide has a long climate record, showing daily rainfall has varied greatly over the years.  There is no recent increase in amount, intensity, or frequency for the whole year, or for the last six months or four months.  Spring and summer rainfall in 2016 was not unprecedented, and to the extent that spring and summer falls over 20mm are a proxy for storms, there is no evidence for an increase in wild weather.  This is normal.  Get used to it, Mr Roberts, and make sure the electricity network can cope.

 

The Pause Update: December 2016

January 5, 2017

The complete UAH v6.0 data for December have been released. I present all the graphs for various regions, and as well summaries for easier comparison. The Pause has ended globally and for the Northern Hemisphere, and the Tropics, and may soon disappear from the USA, and the Southern Hemisphere.  The 12 month mean to December 2016 for the Globe is +0.50 C.

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 38 years and one month long- 457 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 December 2016.

[CLICK ON IMAGES TO ENLARGE]

Globe:

uah-dec-16-globe

The Pause has ended. A trend of +0.32 C/100 years (+/- 0.1C) since March 1998 is creeping up, but the 12 month means have peaked and are heading down.

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:

uah-dec-16-globe-monthly

That’s since December 1997.

Northern Hemisphere:

uah-dec-16-nh

The Northern Hemisphere Pause has well and truly ended.

Southern Hemisphere:

uah-dec-16-sh

For well over half the record, the Southern Hemisphere still has zero trend.  The Pause is about to end.

Tropics:

uah-dec-16-tropics

The Pause in the Tropics (20N to 20S) has ended and the minimal trend is now +.32C/ 100 years.  12 month means peaked mid-year.

As Tropical Oceans closely mimic the Tropics overall, I won’t show their plot.

Northern Extra Tropics:

uah-dec-16-next

The minimal trend is up to +0.6C/ 100 years.

Southern Extra Tropics:

uah-dec-16-sext

The Pause persists strongly, however 12 month means are still rising.

Northern Polar:

uah-dec-16-np

The trend has increased a lot to +2.35C and since February 2003 +0.88C/100 years.

Southern Polar:

uah-dec-16-sp

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

USA 49 States:

uah-dec-16-us49

The Pause has shortened again and is about to disappear altogether.

Australia:

uah-dec-16-oz

The Pause is still 21 years 5 months, and means have peaked.  Will the Australian Pause survive where others have failed?

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

pause-length-dec-16

Note that the Pause has ended by my criteria in all regions of Northern Hemisphere, and consequently the Globe, and the Tropics, but 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-now-dec-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-98-now-dec-16

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.

Global TLT anomalies are now dropping rapidly.  The next few months will be interesting. The Pause will disappear from the USA and Southern Hemisphere soon, but not the Southern Extra-Tropics or Australia. El Nino tropical heat is strongly affecting the North Polar region now, and will affect the Southern Hemisphere early this year.

Dig and Delve Part 2: Running Detrended Data

December 29, 2016

In my last post, Dig and Delve Part1, I showed how running trends are useful for showing the linear trend to any point in a dataseries, and that trends in different regions can be compared, after the first 10 to 15 years (120 to 180 datapoints).

In this post I use running trends to derive running detrended data, and analyse data for various Land regions using UAH anomalies.  Firstly, the following figure shows global mean UAH to November 2016 detrended using the current linear trend:

Fig. 1:  Global data detrended from linear trend

global-detrended-normal

This is the usual way to show detrended data.  It clearly shows where temperatures have been above or below the trend, however with each new data point the detrended data changes.  Running detrended data is calculated for each point as actual data minus  the running trend multiplied by the count of data points plus the running intercept.  Here is a plot of running detrended data and ordinary detrended data for Global UAH.

Fig. 2:  Global running detrended data and standard detrended data.

global-detrended-running-comp

After about 1987 they differ by less than +/- 0.1C, and UAH is accurate to +/- 0.1C anyway.   Note also that when temperatures are rising, running detrended data are greater and when falling, they are lower than standard detrended data.

The benefit of running detrended data is that they never have to be recalculated.  Historic detrended values are preserved.  As well, the running trend per month is conveniently not different from zero (which is why I showed it in Part 1 as degrees per 100 years by multiplying by 1,200), so it is easy to show the detrended data with a zero line.  The detrended value is also a measure of how much each month’s data has contributed to the trend- positive values indicate warming influence, negative values indicate cooling influence on the trend.

I now turn to using running detrended data to analyse what has been happening with Land data recently.

The following plots show running detrended data for Land TLT in the Northern Hemisphere.

Fig. 3:  Northern Hemisphere Land data detrended from running trend

nh-land-det

The large spike in February was followed by a plunge to October, but values in November have returned to trend.

Fig. 4:  Northern Extra Tropics Land data detrended from running trend

next-land-det

Similar to the Northern Hemisphere.

Fig. 5:  North Polar Land data detrended from running trend

np-land-det

Note how much North Polar data fluctuates.  However the Poles only contribute less than 7% to the Global mean.

Summing up:

  • Running detrended data never have to be recalculated, and historic values are preserved.
  • The detrended data show how much each month’s data has contributed to the trend at that point.
  • The recent plunge in Northern Hemisphere Land anomalies is nothing to get excited about as it is the recovery from a huge spike. The November value is still on trend.

The next in this series will use an estimate of discrete Extra Tropics (20-60 North and South) to look at trends and detrended data.

Dig and Delve Part 1: Running Trends

December 22, 2016

This is the first in a series of posts in which I look at monthly Temperature of the Lower troposphere (TLT) anomaly data from the University of Alabama- Huntsville (UAH) in different ways, which readers may find interesting and perhaps useful.

In this post, I bring together ideas from former posts- Trending Trends: An Alternative View and Poles Apart – to compare trends in TLT using running trends.

 

Running Trends

Fig. 1: Global UAH with linear trend

linear-trend-global

This is the standard presentation.  It shows the linear trend as at November 2016.  With every new month of data, the linear trend changes.

By calculating a running trend, that is, the linear trend from the start of the series to every subsequent data point, the trend at each point is preserved, and the trend at the final point is instantly calculated.

Fig. 2:  Global UAH running trend

running-trend-global

Figure 2 shows the historical values of the linear trend at each point, and that global temperatures are demonstrably non-linear.  As I pointed out in Trending Trends: An Alternative View, each new data point will either increase, decrease, or maintain the trend.  The longer the data series, the harder it will be to change the trend: the effect diminishes with time.

(An interesting result of the diminishing effect of temperature on the running trend is that it becomes possible to identify what temperatures are doing from the shape of the running trend plot- in fact, to identify a pause or plateau.  To maintain the trend at say 1.2 degrees Celsius per 100 years, temperatures must continue to rise.  A flat-lining running trend is evidence of increasing temperatures; a rising running trend indicates a rapid increase in temperature; but a decreasing running trend is evidence of a pause or decline in temperatures.  This is not a different definition of the pause, just another indicator.)

For 10 to 15 years, the running trend swings wildly, but after this it settles.  Now it becomes useful for analysis and comparison.

In Figure 2 above, note the large effect of the 1997-98 El Nino on the trend, but the 2009-10 and 2015-16 El Ninos have much less effect on the trend.  They are still identifiable by the increase in trend.

Fig. 3:  Regional UAH running trends

running-trend-all-regions

As we have seen previously, the North Polar and South Polar regions are distinctly different from the rest of the world and from each other.  The North Polar region has had an increasing trend (rapidly increasing temperature) from 1994 to about 2007, then a slow down with another rapid rise in the last 12 months.  All other regions have had decreasing trends since 2002-3, with an uptick in the last 12-18 months, indicating the duration of The Pause.  The trend in the South Polar region has been much lower than the others, hovering about zero for the last seven or so years, and is currently negative.

For completeness, here are the running trends for continental USA and Australia.

Fig. 4:  UAH running trends:  USA 48 States

running-trend-usa48

Fig. 5:  UAH running trends:  USA 49 States

running-trend-usa49

Fig. 6:  UAH running trends:  Australia

running-trend-aus

The next plots compare Land, Ocean, and Mean running trends for the UAH regions.

Fig. 7:  Global UAH running trends: Mean Land, and Ocean

running-trend-land-ocean-mean-global

Note that the mean trend is close to that of the Ocean, but since 1995 and especially 1998, the trend of global land areas is much higher.  Because of the ocean’s large thermal inertia, land areas warm and cool more quickly.  However, since the 1997-98 El Nino, land trends did not decrease but remained high until 2007.  This graph, as any Global Warming Enthusiast (GWE) will tell you, is evidence of warming.  What they won’t tell you is that it is evidence of any type of warming whether natural or anthropogenic- it is not by itself evidence of greenhouse warming.

Fig. 8:  Northern Hemisphere UAH running trends: Mean Land, and Ocean

running-trend-land-ocean-mean-nh

Fig. 9:  Southern Hemisphere UAH running trends: Mean Land, and Ocean

running-trend-land-ocean-mean-sh

Land trends in the Southern Hemisphere, unlike the Northern, did decrease after the 1997-98 El Nino.

Fig. 10:  Tropical UAH (20N – 20S) running trends: Mean Land, and Ocean

running-trend-land-ocean-mean-tropics

Fig. 11:  Northern Extra-Tropics UAH (20N – 90N) running trends: Mean Land, and Ocean

running-trend-land-ocean-mean-next

Fig. 12:  Southern Extra-Tropics UAH (20S – 90S) running trends: Mean Land, and Ocean

running-trend-land-ocean-mean-sext

This region warmed rapidly to 2002-3, then trends decreased.

Fig. 13:  North Polar UAH (60N – 90N) running trends: Mean Land, and Ocean

running-trend-land-ocean-mean-np

Fig. 14:  South Polar UAH (60S – 90S) running trends: Mean Land, and Ocean

running-trend-land-ocean-mean-sp

In all tropical and northern regions, Land trends have been higher than Ocean trends since 1997-98 (2002 for South Polar and Southern Extra-Tropics).  However, North Polar Ocean trends have been higher than Land since 1998.  There is a greater area of ocean than land, and ocean areas have been warming more than land.  This is the opposite of what greenhouse theory predicts.  At the poles, where warming is expected to be greatest, only the North Pole is warming, and here the warming is not greatest over land, but over the ocean.

Summing up:

  • Running trends are an effective way of showing the linear trend at any given month of a data series.
  • They are useful for comparison and analysis after the first 10 to 15 years (the early 1990s).
  • A declining running trend indicates flat or declining temperatures, thus The Pause is visible from 2002-3 to 2014-5 in all regions apart from North Polar.
  • The North and South Polar regions are distinctly different from other regions and each other.
  • Apart from North Polar region, all regions show land areas warming more than ocean areas, indicating warming from whatever cause.
  • In the North Polar region, TLT running trends of ocean areas have been higher than land.
  • These trends, especially at the poles, are not consistent with greenhouse theory.

 

The next post in this series will use running trends to derive running detrended data.

Putting Temperature in Context: Pt 2

December 14, 2016

To show how handy my Excel worksheet is, here’s one I did in the last 15 minutes.

Apparently Sydney has had its warmest December minimum on record at 27.1 C.  The record before that was Christmas Day, 1868 at 26.3C.

The following seven plots show this in context.

Fig. 1:  The annual range in Sydney’s minima:

whole-yr-sydney-min

Extremes in minima can occur any time between October and March.

Fig. 2:  The first 2 weeks of December

14d-sydney-min

Plainly, a new record was set this morning, but apart from Day 340 the other days are within the normal range.

Fig. 3:  7 day mean of Tmin in this period

7d-avg-sydney-min

Extreme, but a number of previous years had warmer averages.

Fig. 4:  Consecutive days above 20C Tmin.

days-over-20-sydney

But there have been longer periods of warm minima in the past.

Now let’s look at the same metric, but for all of December.

Fig. 5:  All Decembers (including leap years).

december-sydney-min

A record for December, with 1868 in second place.

Fig. 6:  7 day mean of Tmin for Decembers

7d-avg-sydney-min-december

Seven day periods of warm nights are not new.  The horizontal black line shows the average to this morning (20.6C) is matched or exceeded by a dozen other Decembers.  (Of course this December isn’t half way through yet.)  Also note what appears to be a step change about 1970.

Fig. 7:  Consecutive days above 20C Tmin in December.

days-over-20-sydney-december

I doubt if 15 December will be as warm as today, but could still be over 20C.

This is weather, not global warming.