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Hottest summer record in Australia? Not so, says UAH satellite data

Posted By Joanne Nova On March 17, 2013 @ 11:58 pm In Global Warming | Comments Disabled

There are probably only ten people in Australia who haven’t heard it was the Hottest Ever, Record Summer Downunder. And they were probably born yesterday.

Summer here was so scorchingly awful it was Angry. But a funny thing happened on the orbit overhead. Check out the UAH satellite data on summers since the UAH records began.  The graph below (thanks to Ken) is the temperature data from the NASA satellites, processed by UAH (University of Alabama in Huntsville). Strangely there is a disparity between what the satellites recorded and the BOM.

The satellite data shows that the summer of 2012-2013 was close to ordinary, compared with the entire satellite record going back to 1979. Not a record. Not even extreme?

According to UAH satellite measurements summer in early 2013 was not a record. Not even close.

The graph data comes thanks to John Christy, Director, Earth System Science Center, Distinguished Professor, Atmospheric Science
University of Alabama in Huntsville, Alabama State Climatologist and Roy Spencer. It was graphed by Ken Stewart at KensKingdom, and inspired by Tom Quirk at Quadrant. I was very happy to connect them this weekend. The data cover “average lower troposphere temperature anomalies for land grids only for the region 10S-40S by 110E-155E.” UPDATE: The data in the graph above does include Tasmania as well, and does not include PNG or Timor.

Perhaps there is some error in the data? But on Ken’s site, you can see he gets a reasonably close correlation for most points with ACORN.

As Ken says:

According to BOM, last summer was a record, yet the satellites say it was pretty ordinary- 14th warmest out of the last 35.  The last time there was such a large discrepancy was 1983- the two series since then have been reasonably similar.

Ken Stewart compared the UAH summer record to the BOM one.

Note though that the other large discrepancy was 1983 which was also a year when the BOM records a very high temperature, and UAH records an average one. Perhaps that is a clue?

The UAH data is not covering the same area as the BOM stats do.

There is no Tasmanian data, and while a lot of surrounding ocean is included in the longitude and latitude, the UAH data is for land-grids only. The black rectangle marks the land covered in the UAH satellite data.

UPDATE: John Christy sent a second set of data to Ken that does include Tasmania and doesn’t include Indonesia and PNG.  I will update the graphic below as soon as I can. The UAH data is more accurate than I thought.

...

Even if the UAH data included some ocean stats leaking into the mix, according to the BOM the ocean was the hottest on record in any case.

The Age quotes the BOM telling us that seas weren’t just warm, and it wasn’t just one month. It was the hottest, and it was all of summer:

Seas around Australia are also warmer than usual, with surface temperatures reaching record highs at the end of February, according to a Special Climate Statement issued by the Bureau of Meteorology in the wake of this month’s heatwave across south-eastern Australia.

Summer sea temperatures were 0.5 degrees above normal and the warmest since records began in 1900, the bureau said.

The Australian BOM says: “Summer ocean surface temperatures around Australia were the highest on record. (March 12)
Note the warm water surrounding the Western and Southern coasts on the latest ENSO map (below).

[Source: BOM ENSO page] March12 2013.

 

Warwick Hughes sharply spotted that data from NOAA/NWS/NCEP Climate Prediction Center didn’t agree either that 2013 was a record summer (though it comes in second). He downloaded and graphed the gridded data from CPC GHCN/CAMS t2m (45°South to 10°South and 110°East to 155°East).  While their difference between CAMS and the BOM were small in 2013, there was a difference in the trends, and CAMS shows that 1983 was the hottest ever, and that 2013 was second, and was almost identical to 1973, 1998, and 1991. (Does NCEP use some Australian BOM surface data?)

Hottest ever media hype?

The BOM have been issuing “hottest summer in Australia ever” announcements for two weeks, even practically before the summer was over. The Angry Summer has been all over the press, especially with this graph.

Despite the title this graph includes the 2013 record high.

Did the BOM plot the UAH comparison? Can they explain the discrepancy?

Even if there is some explanation, the BOM is not giving Australians any indication of how difficult, complex, and questionable these continent wide “records” are. Few of the public would realize that the record depended on tricky and sometimes unpublished methods, on subjective choices made in weighting areas, and subjective decisions on how to adjust individual records.

How many Australians know that “records” could vary with other methods of estimating average temperatures? Or that other data sets managed by other climate experts might not agree?

Can anyone spot an investigative journalist?

Did anyone ask the BOM if there are other ways to calculate “the average temperature of the country”? Did anyone enquire as to whether they had looked at satellite data as well?

 

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Don’t miss your chance to see Lord Monckton in Canberra tonight,

then Wagga, and Albury on Tuesday. Sydney on Wednesday,

and Melbourne and surrounds from Friday onwards.

Details at the Lord Monckton Foundation.

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