A Surface Pressure Altitude Prediction Model
ARMY LAB COMMAND WHITE SANDS MISSILE RANGE NM ATMOSPHERIC SCIENCES LAB
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A surface pressure altitude SPA prediction model has been developed that is totally empirical and based on SPA data from 556 meteorological observation stations in the free world. This model is simple and can be executed very quickly on a microcomputer. The model estimates the mean SPA perturbation SPAP or difference between the SPA and the surface elevation of a station by a sum of numbers that represent the additive effects of month, time of day, station location, interaction of month with station location, interaction of time of day with station location, and an additive constant. A prediction of SPA at a later time is made by taking the current SPA and adding the difference between the modelled mean SPAP for the later time and the modelled mean SPAP at the current time. The model predicts SPA well in the near term at an observing site when the current SPA. is known. The quality of the prediction decays with prediction lay time until about 50 percent of actual SPA variation is accounted for by the predicted SPA at a lag time of 24 h.