Friday, May 11, 2018

TempLS monthly updates of global land and sea temperature

TempLS is a program I use to provide a monthly global land/ocean anomaly index, using unadjusted GHCNM V3 data for land, and ERSST V5 for SST. There is a summary article here. It is essentially a spatial integration, which reduces to an area-weighted average of the anomalies. My preferred method is to use an irregular triangular mesh to get the weights. It is then possible to separately sum with weights the stations of various regions. I have been doing this (as described here) for about three years as part of the monthly reporting. A typical plot for April is here


It shows the arithmetic contribution that each region makes to the published global average. It isn't itself a temperature of something; if you add all the continent colored bars shown, you get the land global amount, in red (that is new). And if you add land and SST you get the global, in black. Each bar is the weighted sum of locals divided by the global sum of weights. To get the regional average, the denominator would be the sum of weights for the region.

I plan now to more systematically post the land and SST averages, and also plots of regional averages. The SST will be particularly useful, because ERSST posts within a couple of days of the start of the month, so TempLS can produce a result much earlier than the alternatives. NOAA publishes a revision late in the month, but changes are usually small.

I have added TempLS_SST and TempLS_La to the sets normally displayed. You can find the numbers (anomaly base 1961-1990) under Land/SST in the maintained table of monthly data. There are trend plots in the Trend viewer. And they plots are available on the interactive plotter. Here is an example of recent data, compared with HADSST3 and NOAA SST:

I'll probably report the SST for each month in my first post for each month, along with the reanalysis average.

I'll show now the other possibilities in the monthly bar plot style. Showing the regional averages give sthis:

The regions are far more variable than the globals, which obscures the picture somewhat. Note the huge Arctic peaks. So I'll show also the progression of just the land, SST and globals. It is now practical to show more months. Here is the plot

It emphasises the variability of land relative to SST. This may be seen in better proportion by reverting to the first style, showing the contributions to the global average:

Again, red and blue (land and SST) add to the black total. It shows how monthly variations are dominated by the fluctuations on land. I'll find a way to include these extra graphs in the monthly reporting.

1 comment:

  1. ENSO provides the climate variability. Coral proxy data from 1650 to 1880 can be used to predict the ENSO behavior after 1880