Extreme La Nina events – an alternative view

January 28, 2015

Yesterday the ABC hyped up their climate alarmism to another new level with their uncritical and unabashed reporting of a claim by the CSIRO that Extreme La Niña events … will almost double in frequency as the climate warms”.

“Lead author Dr Wenju Cai, chief scientist at Australia’s CSIRO Oceans and Atmosphere Flagship, says their work shows La Niña events will occur every 13 years compared with a past frequency of one every 23 years.”

This is the paper:

Increased frequency of extreme La Niña events under greenhouse warming, by Wenju Cai et al., published yesterday.

Time for a reality check.

The authors say they used climate data from 1900 to 2005, and 21 climate models to predict conditions for 2006-2099, and that an extreme La Nina is defined by Central Pacific sea surface temperature anomalies of more than 1.5C below normal.  They claim that an increase in severe El Ninos will lead to an increase in following extreme La Ninas.

In the paywalled article I suspect the Central Pacific region they use is actually the Nino 4 region.  In this analysis I use data from the Nino3.4 region, which is the overlap between Nino 3 and Nino 4, covering Latitudes 5 degrees South- 5 North and Longitudes 170 degrees West- 120 West.  This is the most common data region used.   I downloaded data from http://www.esrl.noaa.gov/psd/gcos_wgsp/Timeseries/Nino34/ and calculated monthly anomalies from the 1961-1990 means.  There are data from 1870, however I chose to use data from 1876 to match Southern Oscillation Index (SOI) data.

Here are the results:

Fig.1: Nino 3.4 anomalies.  Note 1900 & 2005 limits, and +/- 1.5C thresholds.

nino34

By screening for events of +/- 1.5 or more, we remove the clutter and identify extreme events:

Fig.2: Nino 3.4 data exceeding +/- 1.5C

extreme enso events

The paper claims that the incidence of extreme La Ninas will increase from one per 23 years to one per 13 years.  While there are more extreme La Ninas in the last 45 years, I count seven La Ninas from 1900 to 1999, which is one per 14 years.  There were three very high El Nino peaks since 1970, but there are clusters of extreme El Ninos in the first and last thirds of the record.  So possibly the claim for increased La Nina frequency was for an increase in the frequency of abrupt swings from El Nino to La Nina.

Fig.3:  12 monthly change in Nino 3.4 anomalies. +/- 3C is the threshold for swings from extreme El Nino to extreme La Nina.

12m enso chg

Fig.4: Removing the clutter, change exceeding +/- 3C.

extreme enso change

There we have it.  The extreme changes since 1900 have all been in the last 45 years.  Is this due to Greenhouse warming or natural climate change? Could it have anything to do with the Interdecadal Pacific Oscillation? Or is it an artefact of my arbitrary choice of extreme threshold?

More importantly, does the Southern Oscillation Index (SOI) tell the same story?

SOI data are from the BOM website.

Fig.5:  12 month running mean of the SOI inverted.  Threshold is +/- 8.  Note the historical rises and falls.

 12m soi

Fig.6: Nino 3.4 and 12 month inverted SOI match fairly well, although SOI values lag by up to 2 years.

soi v nino34

Fig.7:  El Nino and La Nina conditions per SOI criteria (+/- 8).  An extreme ENSO event might be +/- 16, although I have not seen that mentioned anywhere.

12m soi tests

Again note the clusters of El Ninos, and the spread of La Ninas, in small groups with large gaps between.

Fig.8:  12 month SOI change exceeding +/- 16.  Horizontal lines indicate the threshold for an annual swing of +/- 24 units, which is associated with some dramatic weather events.

extreme  soi change

I left all of the changes >16, to show the historical spread.  Note there were three extreme La Nina (< -24) changes from 1876- 1916, and three from 1960- 2000, and four from 1973- 2014.  There is no unusual trend.

How does this correspond with the observed rainfall record, especially for South East Australia, which is predicted to receive more extremes of rain and drought due to greenhouse warming?

Fig. 9:  Number of months of severe deficiency.

SE Oz severe droughts

Fig. 10:  Number of very wet months.

SE Oz ext wets

Not very alarming.

Queensland is especially susceptible to ENSO events.

Fig. 11:  The match for Queensland wet years is better.

Qld ext wets

Fig. 12:  But not for droughts!

Qld ext dry

Where are the extreme El Ninos?  Call me underwhelmed.

Depending on the index used, the criteria used, and the length of the record used, you can say we’ve had an increase in extreme ENSO swings, or no noticeable change other than a long period (70 to 90 years?) cycle of more and less extreme changes.

My money’s on the latter, but Time will tell.

BOM Admits “Inaccuracy”!

January 21, 2015

At last- 15 days after their widely publicised initial claims (through Mr Jeff Sabburg) that in 2014 Queensland had rain deficiencies not seen since the 1927-1929 drought, and that 37.3% of the State had the lowest rainfall on record- the Bureau has replied to my complaint.

After the Bureau’s initial perfunctory response on Monday 12 January, I asked for straight answers to whether the claims were correct, and would the Bureau correct them in a Media Release.

This morning, 21 January, I received this email:

Dear Ken,
Further to our correspondence we can confirm that media statements made to the ABC by a Bureau employee on 6 January 2014 did not accurately reflect the relative severity of the current Queensland rainfall deficiencies. Unfortunately the Bureau spokesperson misinterpreted some of the information. We have advised the ABC of the inaccuracy and asked them for an opportunity to update the story, if possible.
 
Regards,
Climate Analysis Section

So the answers to those questions were “No”, “No”, and “No, a media release would be too embarrassing and out of the question, so we’ll just advise the ABC and trust this will be buried as old news”.

I will therefore contact other media outlets (e.g. the Queensland Country Life which also ran the story), with a reminder to ABC Queensland Editor Genevieve Hussey, hoping that people across Queensland are made aware that the drought conditions (terrible as they were and still are for many) were not as bad as reported.

While this is a satisfying outcome for me, it is over two weeks since these “inaccuracies” were widely reported across Queensland in the three media that rural people mostly turn to: ABC Radio Country Hour, ABC TV 7.00 p.m. News, and the Queensland Country Life.  I cannot believe that no one in the Bureau saw these reports and did anything about the falsehood, but I’m not surprised.

If you make a mistake, own up quickly, or trust will dry up faster than the rain.

 

How not to admit a mistake

January 12, 2015

Well that explains everything I guess.  Not.

Here is the reply to my query to the Bureau regarding the claim that 2014 saw “the worst drought in 80 years.”

Dear Ken,
Thank you for your email.
The Bureau’s official publicly available Drought Statement is online at http://www.bom.gov.au/climate/drought/
 
Regards,
Climate Analysis Section
National Climate Centre – Bureau of Meteorology 

Short, sharp, but not exactly to the point.

The relevant paragraphs from the Drought Statement read as follows (my bolding):

It is generally difficult to compare one drought to another, since each drought differs in the seasonality, location, spatial extent and duration of the associated rainfall deficiencies. Additionally, each drought is accompanied by varying temperatures and soil moisture deficits.

The current drought in Queensland is comparable to the 2002–2003 drought, which was perhaps more severe in terms of rainfall deficiencies that occurred at times over a very large area. Historical data shows that the current drought is perhaps a one in ten or twenty year event over a significant part of inland eastern Australia (see for example the 24-month deciles map for 2013–2014), but very severe in some places. For example, some location in central Queensland the present deficiencies are the most severe on record, and in addition have been accompanied by record high temperatures. See: 24-month maximum temperature deciles map for 2013–2014.

Nowhere can I find any reference to “the worst drought in 80 years” or rainfall deficiencies not seen “across Queensland at least since the 1927- 1929 depression drought” or “37.3% of the state… covered by the lowest rainfall on record”.  Also included in the Drought Statement is this map showing 27 month rainfall deficiencies:

qld drought 27m

Perhaps 37% is covered by serious deficiency, but not the lowest on record.So are they admitting the reports were wrong?  I don’t think so.

I will email them again asking for a specific reply, preferably Yes or No, to the questions:

Was Mr Jeff Sabburg correct in saying “In terms of rainfall deficiencies the comparison is we haven’t seen this across Queensland at least since the 1927- 1929 depression drought”?

Was Mr Sabburg correct in saying “37.3% of the state was covered by the lowest rainfall on record”?

If the answer to either of these is “No”, will the Bureau immediately issue a correction in a media release?

I live in hope.

Not the third hottest year either

January 11, 2015

According to the Bureau’s surface temperature record, 2014 was the 3rd hottest year on record.  The satellite derived Lower Troposphere data from UAH (University of Alabama- Huntsville) show a different picture.

uah aust 2014

If rankings are important to you, 2014 at +0.40C was in equal seventh place with 2006, and cooler than 1980, and warmer than 1988 by 0.01C.

2013 0.71 1
2009 0.64 2
1998 0.63 3
2005 0.51 4
2007 0.50 5
1980 0.49 6
2014 0.40 7
2006 0.40 8
1988 0.39 9
2002 0.23 10
1991 0.22 11
2010 0.22 12
1996 0.17 13
2008 0.16 14
2012 0.14 15
2011 0.10 16
1990 0.09 17
2004 0.02 18
1981 -0.01 19
1995 -0.04 20
2003 -0.05 21
1982 -0.12 22
1979 -0.13 23
1999 -0.15 24
1985 -0.22 25
1989 -0.22 26
1987 -0.22 27
1997 -0.22 28
2000 -0.24 29
2001 -0.29 30
1986 -0.29 31
1993 -0.29 32
1983 -0.36 33
1994 -0.38 34
1992 -0.56 35
1984 -0.62 36

But don’t expect to find this reported by the ABC.

ABC reply to my complaint

January 8, 2015

I was expecting to wait four  weeks, but I received a reply to my complaint about the “worst drought in 80 years” news item in less than 24 hours.  Here it is:

Dear Ken,
Thank you for taking the time to email us regarding a story on the 7pm television news.

The information in our report was based on an interview with climatologist Mr Jeff Sabburg from the Bureau of Meteorology. He was also interviewed by the ABC Country Hour the same day as the annual climate statement was released and said:

“In terms of rainfall deficiencies the comparison is we haven’t seen this across Queensland at least since the 1927- 1929 depression drought. These heat waves we’re getting a number of days in a row above 30- 40 degrees Celsius and then not getting reprieve at night time that’s certainly contributing to the point where there’s nothing much to evaporate away.”

In the 2014 climate statement it also states:

Prolonged rainfall deficiencies continued for inland and south-eastern Queensland and north-eastern New South Wales.

Rainfall was below to very much below average across the South West Land Division and coastal Gascoyne in Western Australia, the majority of Victoria, southeast South Australia, all of Tasmania and a large area covering northeast New South Wales and southeast Queensland.

The story was written based on this information provided.

Thank you for your feedback.

Regards,

Genevieve Hussey
Queensland News Editor

Journalists obviously do not have the time (or, probably, the ability) to check data for themselves.  If they did, they would have seen that this claim is absolutely without foundation, as I showed in yesterday’s post.  However, such a claim must surely have raised some query, some (dare I say) skepticism, as basically Jeff Sabburg has claimed last year saw the worst drought in living memory.  Surely someone at the ABC can remember as far back as 11 or 12 years ago when rainfall deficiencies were demonstrably worse than they have been last year.

The ball now is in the court of the Bureau of Meteorology, who also received feedback from me.

But thanks to Genevieve Hussey for the unexpectedly swift response.

And because I respect and admire any journalists ready to criticise blind faith, whether it be Islam, Christianity, or Global Warming, despite threats,

“JE SUIS CHARLIE”.

Not the Worst Drought in 80 Years

January 7, 2015

Last night on the 7.00 p.m. ABC TV Queensland news there was a report on the Annual Climate Statement 2014 released by the Bureau of Meteorology yesterday (January 6).  I could not believe my ears, and as soon as it was on iview ( http://iview.abc.net.au/programs/abc-news-qld/NC1530Q005S00 ) I checked- several times.

The reader, Matt Wordsworth, clearly reports that the Bureau says Queensland has experienced “the worst drought in 80 years”.  The Bureau’s Jeff Sabburg was interviewed and claimed that 37.3% of the state was covered by the lowest rainfall on record.

Now I do know that much of Queensland has been very dry for a long time, with the northwest being especially bad, having missed two wet seasons (2012-13 and 2013-14).  Before you think I am callous, uncaring, and uninformed, I should let you know I was raised on a farm, my parents, grandparents, and great-grandparents were farmers, my brother and my brother-in-law are farmers, and I take a very keen interest in the land.

However, both the ABC news item and Jeff Sabburg’s claim, if quoted correctly, are complete nonsense.  Nothing like 37% of the State has had the lowest rainfall on record, and the drought is definitely not “the worst … in 80 years”.  The facts from the Bureau’s own websites (Climate Maps and Climate Change and Variability) show otherwise.

There follows a series of graphics clearly showing the state of Queensland’s rainfall and drought record.

Fig. 1:  12 month rainfall deficiency

qld 12m drought

Obviously recent rain has improved the situation, but what about over the last two years?

Fig. 2: 24 month rainfall deficiency

qld 24m drought

A-hah, that’s showing quite a lot of serious and severe rainfall deficiency, but not a lot of “lowest on record”.  However, compare that with the 24 month period to December 2003.

Fig.3:  24 months to December 2003

qld 24m drought 2003

I have been looking at Queensland rainfall closely in the past couple of weeks.  Here are some other ways of showing rainfall for Queensland.   I have shown 2013-2014 and 1929-1935 (the supposed 80 year ago worse drought), and more recent events, for ease of comparison.

Fig. 4: 12 month running mean of rain anomalies

qld rain 12m

Fig. 5:  24 month running mean of rain anomalies

qld rain 24m

Fig. 6:  27 month running mean of rain anomalies (covering the previous two wet seasons)

qld rain 27m

There was nothing unusual about Queensland’s rain in 2014.

The next graphics are plots of the 12 month counts of 12 month running means of rainfall with below average (bottom 30%), very much below average (bottom 10%), and severe deficiency (bottom 5%) rainfall.  In other words, counts of 12 month periods (January – December, February – January, March – February etc) with rainfall in each category.

Fig. 7: Count of 12 month periods of below average rain (lowest 30% of 12 month periods)

qld drought counts 12m belavg

Fig. 8: Count of 12 month periods of very much below average rain (lowest 10% of periods)

qld drought counts 12m verybelow

Fig. 9: Count of 12 month periods of severe rain deficiency (lowest 5% of periods)

qld drought counts 12m severe

There have been no episodes of statewide severe rain deficiency since January 2004.

Fig. 10: Count of 12 month periods of 24 month below average rain (lowest 30% of 24m periods)

qld drought counts 24m belavg

Fig. 11: Count of 12 month periods of 24 month very much below average rain (lowest 10% of periods)

qld drought counts 24m verybelow

Fig. 12: Count of 12 month periods of 24 month severe rain deficiency (lowest 5% of periods)

qld drought counts 24m severe

Fig. 13: Count of 12 month periods of 27 month below average rain (lowest 30% of 27m periods)

qld drought counts 27m belavg

Fig. 14: Count of 12 month periods of 27 month very much below average rain (lowest 10% of periods)

 qld drought counts 27m verybelow

Fig. 15: Count of 12 month periods of 27 month severe rain deficiency (lowest 5% of periods)

qld drought counts 27m severe

And just for information, this map shows the 36 month rainfall deficiencies to December 1902.

Fig. 16:  36 months to December 1902- the Federation Drought

qld 1902 36m drought

Now that’s a drought!

The current drought, bad as it is, barely rates when compared with previous droughts.

Perhaps the Bureau is using different data from what is shown on their websites.  Perhaps Jeff Sabburg was quoted out of context.  Whichever way, the public has been misled- not for the first time, and unfortunately not the last.

The Bureau of Meteorology should issue an immediate clarification, and the ABC should issue an immediate apology and correction.

2014 in review

December 30, 2014

The WordPress.com stats helper monkeys prepared a 2014 annual report for this blog.

Here’s an excerpt:

The concert hall at the Sydney Opera House holds 2,700 people. This blog was viewed about 19,000 times in 2014. If it were a concert at Sydney Opera House, it would take about 7 sold-out performances for that many people to see it.

Click here to see the complete report.

How Much Warming Have School Leavers Seen?

December 7, 2014

Reports of the recent heatwave and record high temperatures in November (which coincided with the end of schooling for our Year 12 students), have been exciting the media here in Australia, and last week Professor Lesley Hughes of the Climate Council got herself overheated and joined in.

Professor Hughes, an ecologist, this year was awarded the Australian Government Eureka Prize for Promoting Understanding of Australian Science Research.

prof hughes

See  http://australianmuseum.net.au/media/2014-Eureka-Promoting

Last week, she claimed that “climate change was having a significant impact on Australia’s temperatures, with record-breaking weather becoming more frequent and more severe.”

“Nine of the 10 warmest springs have occurred in just the last 13 years,’’ Prof Hughes said. “Heatwaves are becoming hotter, lasting longer and occurring more often.

“This is resulting in year after year of recordbreaking temperatures, which increases the risk of bushfires, droughts and heatwave-related health issues.”

How much of this frightening climate change have the current school leavers experienced?

Here are some graphs of Australian monthly temperature anomalies, straight from the Bureau’s Climate Change website, for the entire period of their schooling- from January 2002 to November 2014 (Preschool to Year 12 in Queensland).

Minima:

aust min 2002-14

Yes, over the past 13 years minimum temperatures have increased at a rate of about +0.08 degrees C per decade, or +0.8 C per 100 years- but less than the post 1910 trend of +0.1 C per decade.

Maxima:

aust max 2002-14

Oops! Over the whole period of the school leavers’ education, maxima have decreased at -0.06 degrees per decade.

Means:

aust mean 2002-14

Throughout their school years our school leavers have experienced a warming trend of…. +0.01 C per decade.  Or about 15 thousandths of a degree over 13 years.  Even with the hottest November on record, that’s somewhat less than the trend of +0.9 C per decade since 1910.  I’d call that a slowdown.

Welcome to the real world, school leavers.  It’s not as frightening as Professor Hughes (or Barack Obama) would have you believe.

Rain, clouds, and temperature

November 19, 2014

Looking at the continent of Australia as a whole, and using 12 month running means to smooth the very noisy data, we can see some intriguing patterns.

Firstly, here is a comparison of tropospheric temperatures above Australia from the University of Alabama- Huntsville (UAH), with surface air temperatures from the Bureau of Meteorology’s ACORN-SAT database.   To be comparable, both datasets are in anomalies from their 1981 – 2010 means.  The data are monthly since December 1978, with a 12 month running mean.

Fig. 1

uah v mean

Both datasets show concurrent rises and falls and are very similar (though not always).  Note how Acorn means were very much cooler in 2011 -2012 and much hotter in 2013.  Note also that 2014 has Buckley’s of being the hottest year on record.

Mean equals the average of maximum and minimum, so let’s look at maxima and minima.

Fig. 2

uah v max & min

Note that UAH usually tracks Acorn maxima, except when it doesn’t- shown above by the Xes.

Perhaps it has something to do with rainfall, or lack of it.  In the next plot, rainfall is inverted, so dry is at the top, wet at the bottom.

Fig. 3

uah v rain inv

Incidentally, the Bureau also has 9 a.m. and 3 p.m. cloud data available.  Note how closely both cloud datasets match, and how rainfall largely corresponds.

Fig. 4

rain v cloud

And the Southern Oscillation Index runs in close partnership with rainfall- sometimes SOI leads rain, sometimes rain leads SOI.

Fig. 5

rain v soi

Which is why I don’t take a lot of notice of predictions based on SOI.

Now see what happens when we plot inverted rainfall (dry at the top, wet at the bottom) and maxima.

Fig. 6

rain v max

Only once does 12 month mean maximum temperature precede 12 month rainfall (1991-1992).  At all other times, rainfall peaks or troughs occur before maxima (or at most, simultaneously).

With minima, the lead is even more obvious, however there are apparent exceptions in 1982 and 1994-1995, although these may be further examples of rain leading minima by more than a year (marked with “?”).

Fig. 7

rain v min

When we compare maxima with minima, the pattern is clear.

Fig. 8

max v min

Only in the summer of 1994-1995 do the records diverge.

Generalisations (and farmers have known about these rules of thumb for years):

  1. Climate is cyclical.  Rain and temperature rise and fall in roughly two or three year cycles.
  2. It always rains after a drought.
  3. Dry years are followed by spikes in maximum and minimum temperatures, from one to several months later.
  4. Wet years, with heavy cloud and rain, cause sharp drops in minimum and maximum temperatures, from one to several months later.
  5. Maximum temperatures lead minimum temperatures by several months in wet years, and by a shorter period in dry years.
  6. There are exceptions to all of the above.

Next step: Australia is a large continent with several distinct climatic regions.  I will next look at smaller regions to see if the above generalisations hold true and indeed may be modified or enhanced.

More Bizarre Adjustments

November 5, 2014

In September, the Bureau of Meteorology added two extra tabs to its ACORN-SAT webpage, in response to media and public pressure.  The first tab (“Adjustments”) included a link to a list of temperature adjustments for each of its 112 Acorn stations.  (This had been promised two and a half years earlier.)

Soon after, and probably in response to continued interest in adjustments at Amberley, Rutherglen, and Deniliquin (amongst others), six links to PDF files were added at the bottom of the adjustment page, which gave further explanations and summaries of adjustments at six individual sites- Amberley, Deniliquin, Mackay, Orbost, Rutherglen, and Thargomindah. (Click to enlarge.)

station summaries

Two days ago I posted about the bizarre case of Mackay 33119, listing differing adjustments from the two sources, extra neighbours found, and finding that the set of adjustments in the individual summary did not match the end result (the Acorn record for Mackay).

I thought this must be just a freak problem with Mackay.  Surely the other examples couldn’t all be wrong.

Not so.

Here is a table summarising the adjustments listed by the Bureau in the 28  page Station adjustment summary list, compared with the individual station summaries (click to enlarge).

adj comp table

Only one station (Deniliquin) has matching pairs of adjustments- but none are the same.

Out of 25 pairs of matching adjustments, only one pair has the same adjustment.

Most of the adjustments differ by only a few hundredths of a degree, but some are hugely different (over 1 degree in the case of Mackay).

There are a total of 60 adjustments, but 10 of these do not have a matching adjustment.  Seven of the extras are in the individual station summaries, three are from those in the original 28 page list.

Note that these station summaries are “indicative of the sorts of adjustments made across the 112 ACORN-SAT sites”. As a result, we can have no confidence in the accuracy of the Bureau’s adjustments, and we are left wondering what the Bureau would have us believe are the real temperatures at any site.

An old school teacher’s response to such sloppy work?

Fail.  Check your work and repeat.  Stay in at lunch time until you get it right.


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