Thursday, March 5, 2020

February in ConUS - surface anomalies mostly warm - new graphics.

This post follows one here where I described a new way of calculating an average temperature for a region like ConUS (USA, lower 48 states) and showed comparative graphics for January 2020. I use GHCN V4 data, and there is now enough out to do a February post. It was warm like January, in most parts. I'll link below to a set of numerical data for ConUS for all months since 1900.

I use 2005-2019 as the base period for anomalies, to make possible comparison with USCRN. But I won't show USCRN here, because the greater station numbers in GHCN give a better result. Probably in production I'll revert to the WMO base of 1981-2010. I use GHCN unadjusted here; visually, it makes no difference. Here is the result for February 2020:

I realised that I could also usefully compare this graphic with the WebGL global plots that I show as the data comes in. These are the most detailed early depictions of the data. Here is a zoomed extract from that source:

Both plots have the property that the color at each station is correct at that point, and elsewhere is interpolated. The WebGL plot is based on triangular mesh with linear interpolation; the new plot uses the Laplace infilling, which is smoother.

Next I'll show the corresponding plots for 2019. At some stage I'll set up a page which goes back further. This one is done in the usual style where the buttons below let you cycle through the months.

Historical results and comparisons.

I'll post soon with an analysis of comparison with other data. I'll post a link to the table here. The table shows the NOAA data for ClimDiv and USCRN, and my corresponding averages using data from GHCN V4 adjusted, unadjusted and USCRN. All results have been set to anomaly base 2005-2018.


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