I’ve moved to WordPress. This post can now be found at Part 2 of Comparison of GISTEMP and UAH MSU TLT Anomalies
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INTRODUCTION
In the first part of this post, Part 1 of Comparison of GISTEMP and UAH MSU TLT Anomalies, I illustrated that global GISTEMP had a higher linear trend than UAH MSU TLT--nothing earth-shattering there. But that post also divided the globe into 8 subsets and compared the linear trends for those smaller areas of the globe. In this post, we’ll look at Land Surface Temperature and TLT anomalies for each of the continents to further illustrate any differences between the GISTEMP and UAH MSU TLT data.
AREAS FOR THE COMPARISONS
The KNMI Climate Explorer website provides access to GISS Land Surface Temperature data that is separate from SST data. The UAH MSU TLT data available through KNMI, however, is not separated into land and ocean subsets. And due to the shape of the continents, there is no way to gather the TLT anomalies over the complete continental land masses without also getting TLT anomalies over portions of the oceans. Therefore, for this comparison of Land Surface Temperature anomalies and the TLT anomalies over those same land areas, I subdivided the data into smaller areas of the continents to minimize any influence from ocean data.
Figure 1 illustrates the global grids used in the comparisons of GISTEMP Land Surface Temperature and UAH MSU TLT anomalies. The coordinates are listed on the graphs that follow. Also, an area of Siberia seems to have had elevated surface temperatures in recent years (though it did not make an appearance in the most current map [May 2009] of Surface Temperature Anomalies, Figure 1). I’ve attempted to capture that “Siberian Hotspot” in the area enclosed in purple.
http://i41.tinypic.com/i1k28l.pngFigure 1
CONTINENTAL SUBSECTION COMPARISONS
Figure 2 illustrates the Australian GISTEMP Land Surface Temperatures and UAH MSU TLT anomalies for the same land mass area. The GISTEMP linear trend is negative (-0.011 deg C/decade), while the UAH MSU TLT linear trend is positive (0.11 deg C/decade).
http://i40.tinypic.com/20h7f3t.pngFigure 2
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For the Central North American data, Figure 3, the GISTEMP linear trend of 0.201 deg C/decade is also less than the UAH MSU TLT linear trend of 0.224 deg C/decade.
http://i40.tinypic.com/nget8k.pngFigure 3
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The Northwestern North America datasets, Figure 4, include most of Western Canada. The UAH MSU TLT linear trend (0.256 deg C/decade) is greater than the GISTEMP linear trend (0.169 deg C/decade).
http://i43.tinypic.com/f44ljb.pngFigure 4
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It is unfortunate that the UAH MSU TLT data is not separated into ocean and land data on the KNMI Climate Explorer website. I did look for other websites where I could download the separate land and ocean TLT anomalies, but if one exists, it eluded me. The comparison of European land surface temperature and TLT anomalies required that I whittle down of the area covered to minimize any influence of ocean data. Refer again to the map in Figure 1.
The “Eurasian Strip” data, Figure 5, should at least capture the “core” temperatures for Europe. The 0.475 deg C/decade linear trend for GISTEMP is higher than the UAH MSU TLT linear trend of 0.426 deg C/decade.
http://i40.tinypic.com/k6ija.pngFigure 5
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Travelling east, the shape of Asia allows a comparison of a much larger land surface area. The GISTEMP linear trend (0.438 deg C/decade) in the Asian comparison, Figure 6, is significantly higher than the UAH MSU TLT linear trend (0.237 deg C/decade).
http://i42.tinypic.com/10ylzjc.pngFigure 6
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For the “Siberian Hotspot,” Figure 7, the difference in the trends is less that the difference for the Asian datasets with the larger surface area. The GISTEMP linear trend for the "Siberian Hotspot" is 0.451 deg C/decade, while the UAH MSU TLT linear trend is 0.317 deg C/decade.
http://i43.tinypic.com/mw38mq.pngFigure 7
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Figure 8 illustrates the significant difference in the linear trends for the South American data. The UAH MSU TLT linear trend (0.097 deg C/decade) is much less than the GISTEMP linear trend (0.237 deg C/decade). The GISTEMP linear trend is more than twice that of the UAH MSU TLT data.
http://i41.tinypic.com/16idyc7.pngFigure 8
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The difference between the GISTEMP and UAH MSU TLT data for Northern Africa, Figure 9, is also substantial. The linear trend for the UAH MSU TLT data is 0.094 deg C/decade, but the GISTEMP linear trend is more than 3 times greater at 0.306 deg C/decade.
http://i43.tinypic.com/if1oh5.pngFigure 9
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As illustrated in Figure 10, the UAH MSU TLT linear trend for Southern and Central Africa is a relatively low, only 0.031 deg C/decade. The GISTEMP linear trend, on the other hand, is 0.276 deg C/decade.
http://i40.tinypic.com/1hb5sm.pngFigure 10
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For the last comparison, I used the “SoPol” land data from the UAH MSU TLT webpage:
http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
Similar to the difference shown in the comparison of the land plus ocean data for the Antarctic, the GISTEMP Antarctic Land Surface Temperature shows a positive trend (0.055 deg C/decade) while the linear trend for the UAH MSU TLT data is negative (-0.113 deg C/decade). Refer to Part 1 of Comparison of GISTEMP and UAH MSU TLT Anomalies for a further discussion of the differences in the Antarctic data. It’s primarily a presentation of the unusual timing of the mid-1990s rise in the GISTEMP data. That rise and fall is not a result of the 1997/98 El Nino. It precedes the 1997/98 El Nino.
http://i40.tinypic.com/707vuo.pngFigure 11
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SOURCE
The GISTEMP Land Surface Temperature and UAH MSU TLT data (with the exception of the Antarctic Land TLT data) are available through the KNMI Climate Explorer website:
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
