Monday, August 1, 2011

First TempLS CRUTEM3 reconstructions.

I've run TempLS V2.2 reconstructions using recently released CRUTEM station data. I've written about the station data here and here.

There are many comparisons I could do. For this post, I'll start by comparing the already published CRUTEM3 averages with the GISS equivalent. Then I'll show monthly averages calculated direectly (by TempLS) from the new data, compared with the published averages. Personally, I think the land/sea averages are much more significant, so I'll show the corresponding results there, using HADSST2 data.

As a general observation, I would say that my land reconstruction tracks fairly well, but rises significantly over the last decade. The TempLS calc makes no adjustments for UHI or anything else. The Land/Sea average shows the same tendency, but much less so.
Update - Steven Mosher has posted his RghcnV3 reconstruction from CRUTEM3 data, which showed similar recent variations,

All anomaly plots are set to a 1961-90 base period. I have used two weighting methods. Method 2 is just by inverse station density calculated from 5x5 lat/lon "rectangles". Method 0 is calculated using equal area rectangles, equivalent to 5x5 at the equator. This method, new in V2.2, is intended to be used with a scheme to redistribute weighting when cells are empty. That actually gave results which were noticeably different. I think it is actually the right thing to do, so the differencemay well be an improvement, but I need to check more to see that it isn't just a mistake.


Sources

CRUTEM3 data CRUTEM3 Ave HADCRUT3
GISS Land GISS Land/Sea HADSST2

Comparison of Giss and Crutem3 Land Indices

Crutem3 is the published CRUTEM average. TempLS reconstruction starts in the nexr section.





Comparison of Crutem3 ave with TempLS Land reconstruction

As mentioned, two weighting schemes were used and are indicated with _0 and _2 respectively. Smoothing is done with 12-month and 60-month moving averages.






Recent monthly deviation:


Tracking peaks:

Comparison of HADCRUT3 ave with TempLS Land/Sea reconstruction

These are Land/Sea reconstructions, and TempLS uses HADSST2 sea surface temp data on a 5x5 degree grid.In the legend, CruSST is the TempLS reconstruction, Hadcrut3 the published average.





Unsmoothed monthly


2 comments:

  1. Very nice Nick!

    I'm about to give up on an automated way of correcting the missing lat/lon and will probably just create a hand correction file. Then I'll see how I compare.

    Steve

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  2. Done

    http://stevemosher.wordpress.com/2011/08/01/cru-data-in-rghcnv3/

    Also a bit warmer. I'm wondering if we have source data and not adjusted data. In anycase when I add in the ocean ( which I match perfectly ) the differences will be mousenuts

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