SPACE-TIME PRECIPITATION REFLECTING CLIMATE-CHANGE

A methodology has been developed and applied to an eastern Nebraska, U SA, case study to estimate the space-time distribution of daily precip itation under climate change. The approach is based on the analysis bo th of the type and of the Markov properties of atmospheric circulation patterns (CPs), and a stochastic linkage between daily (here 500 hPa) CP types and daily precipitation events. Historical data and General Circulation Model (GCM) output of daily CPs corresponding to 1 X CO2 a nd 2 x CO2 are considered. Time series of both local and regional prec ipitation corresponding to each of those cases were simulated and thei r statistical properties were compared. Under the dry continental clim ate of eastern Nebraska, a highly variable spatial response to climate change was obtained. Most of the local and the regional average preci pitation values reflect, under 2 x C0(2), a somewhat wetter and a more variable precipitation regime in eastern Nebraska. The sensitivity of the results to the GCM utilized should be considered.