Physical disaggregation of numerical model rainfall

A methodology is presented for the disaggregation of numerical model fields of convective rainfall using a physically based procedure. The scheme uses surface sensible heat flux values derived from high-resolution multichanne l satellite radiometer observations. The sensible heat flux values initiali se a simple convective model to calculate the convective disaggregation par ameter (CDP), which is theoretically proportional to the convective rainfal l rate. The CDP diagnostic parameter can be derived as a one-time field if the surface characteristics are invariant, as a seasonal value may be, or i t may be evaluated on a case by case basis. Once found, the CDP can be used to disaggregate numerical weather prediction (NWP) convective rainfall fie lds for as far ahead as such fields are produced.