Initialization of Cloud and Radiation in the Florida State University Global Spectral Model
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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Satellite observed Outgoing Longwave Radiation OLR is used to initialize the clouds and radiation of the Florida State University Global Spectral Model. A one-parameter method and two different six-parameter methods of initialization are formulated. The one-parameter method is shown to be the most efficient and produce the best results. The effects of the cloud and radiation initialization on a five day forecast are presented. The initialization procedure a better forecast of OLR than the control experiment by such a large extent that the five day forecast of the initialization experiment has approximately the same verification score as the initial data of the control experiment. The cloud forecasts high, middle, and low of the initialization experiment prominently show the cloud signatures of the monsoon, the Pacific and Atlantic Ocean ITCZs, and the African rainbelt, but the cloud signatures of the control experiment are weak or nonexistent. The moist static stability budgets show that the initialization procedure had a large impact on the forecast after five days of integration by producing a monsoon and typhoon that were stronger and better defined. Additionally, radiative destabilization forcing budgets of the initialization experiment were an order of magnitude greater than the control experiment for the Atlantic Ocean ITCZ. The effect of initialization on precipitation forecasts was also investigated. It was found that the model precipitation decreased after initialization. This attributed to the model formulation of precipitation and a new formulation is suggested for further investigation.