Sunday, September 11, 2011

Weatherwise and otherwise

The climate science debate seems to have cooled off but it has raised various questions on data and its accessibility. Apparently most weather data has not been digitized and in some countries in Africa and South America, data has been gathered only since the mid 20th century. India has been extremely fortunate that data collection began early with a large network of stations. It is however extremely unfortunate that this legacy of data has effectively been made useless by bureacratic procedures and a lack of a public-domain release policy on data.

One project however seems to have made good with whatever has been available and made extrapolations to fill up blanks and smoothen any bumps. WorldClim  - has made these layers available and hordes of researchers who have no better data to use make use of it.

After a day of downloading various layers for four-tiles that India straddles and merging them and formatting them, I found that it is quite educative to see how the bigger picture of temperature and precipitation looks. Here are four animated PNGs showing temperature and precipitation parameters in the region (Firefox and Chrome apparently support APNG, in case you see a static picture - its time to change your browser)
Monthly minimum temperatures

Monthly maximum temperatures
Monthly mean temperatures

Monthly precipitation

If governments could liberate satellite remote-sensing, weather and demographic/health (without personal information) data, the results could be so useful and revealing to everyone.

Worth reading
Post script
There is a bit of a lie effect in the rainfall map. The colouring scheme and bin choice makes it look like the South Asian region is a green paradise. Here is another with a slightly altered binning and colouring scheme which emphasises the drier parts.

Monthly precipitation (version 2)

Lie factor - a term introduced by Edward Tufte - More on this here, and a result of looking for the link got me to sit and read an interview with Tufte which like his books is just as interesting.

Also NASA has a number of data layer at a lower resolution. Here is a rendering of Relative Humidity using their data. You can find a number of nice animations out there as well.
Relative Humidity (%)