MarkSim: Tackling the data divide with high-resolution synthetic weather data.

The lack of reliable weather data, and the profound uncertainties that this creates, remains a major impediment to agricultural development in the tropics. It affects farmers, and policymakers and researchers who aim to support them. In the developed world, literally billons of dollars are invested to acquire information about the weather, but it is unrealistic to expect even a fraction of this investment for tropical regions, so cost-effective methods are required to generate estimates that look like this expensive daily weather data, but at a fraction of their cost. MarkSim™ represents the culmination of over 25 years of world-class research to solve this problem, by simulating high-resolution, daily weather data for the entire pan-tropical region. It does this on the basis of the statistical characterization (Markov simulation) of data from 11,000 weather stations worldwide, and estimating similar values for each 18-km grid cell. The MarkSim method has been rigorously tested, and has now been released as a Windows® commercial version on CD-ROM with a 96-page users' manual.

MarkSim has been applied to the output from Global Circulation Models (GCMs) to create daily weather data for 25 and 50 years from now. These were used as input to the DSSAT crop simulation model and thereby predict the likely impacts of climate change on maize production in Latin America and Africa. The results show complex effects of climate change. In a few areas, yields appear to increase. In many areas, a mild yield decrease could be handled by varietal change and breeding for increased stress. In others, the prospects for continued agriculture are poor, and major changes in the agricultural system seem evident. Overall, the yield decrease could be 10%, or $2 000 000 000's worth of maize crop.

FloraMap version 1.01 is now released and available. FloraMap, MarkSim's stable mate, has completed its first print run of 500 in just over 1 year, and is being used by an estimated 200 active researchers. The manual has been fully revised, a new section added in the theory chapter describing the new data rotation incorporated (now downloadable form the CIAT Web site), and new climate grids included. A further 200 CD-ROM copies were burned of this new version of FloraMap, which, along with a reprint of the updated manual, will satisfy demand until the major release of FloraMap 2.0 that we hope to achieve in 2003.