An Experiment in the Use of Satellite Data in a Numerical Cloud Prediction Program

Abstract

Cloud data derived from TIROS VII photographs over the North Pacific area were used to supplement synoptic surface cloud data in an automated layered-nephanalysis program. During the test period, cloud data from nine TIROS VII orbits were used in the automated layered nephanalyses. These nephanalyses provided additional moisture data input over sparse-data areas to the Air Weather Service Numerical Cloud Prediction program. The total-cloud cover forecasts were improved for 12-, 24- and 36-hr periods. Improvement in the layered-cloud forecasts also was found in the case of moisture decreases at the 700- and 400-mb levels. Other layered-cloud modifications were inconclusive. The importance of establishing a reliable initial moisture field over low-density areas for input to the cloud forecast program was confirmed. Although further refinements must be made in the designation of cloud layers and the merging of satellite cloud data with primary cloud observations, the study showed that satellite cloud data can be effectively processed as input to automated nephanalyses and cloud forecast programs.