Tuesday, November 3, 2009

Two graphs of rainfall and temperature in Darfur

I've been fooling around with the Willmott-Matsuura global climate data, partly at the prompting of some readers of my paper (with Leslie Gray) on rainfall in Darfur before the war, who kindly suggested looking at temperature data also. At the time we didn't have the temperature data available.  These rainfall and temp averages are unweighted averages of the raw data which is on.5x.5 lat-long grid. The slow and steady upwards climb in temperature of the hottest month (the annual average temperature seems a similar increase), about two degrees centigrade over 58 years, is very disturbing.

That said, I don't think the Willmott-Matsuura data is that useful for small-scale regional analysis. Notice that the four quadrants of Darfur are very correlated- about .95- suggesting to me that probably they are coming from a single source and are then being adjusted by being smoothed with other sources further away. There is, after all, a large mountain complex at the intersection of the quadrants so presumably the temperatures would not be so very closely correlated in the "real" world.

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