Vertical profiles of latent heat release and their retrieval for TOGA COARE convective systems using a cloud resolving model, SSM/I, and ship-borne radar data

Latent heating profiles associated with three TOGA COARE active convective episodes (December 10-17 1992; December 19-27 1992; and February 9-13 1993) are examined using the two-dimensional version of the Goddard Cumulus Ense mble (GCE) Model, and retrieved by using the Goddard Convective and Stratif orm Heating (CSH) algorithm. The following sources of rainfall information are input into the CSH algorithm: Special Sensor Microwave Imager (SSM/I), shipborne radars and the GCE model. Diagnostically determined latent heatin g profiles are calculated using 6 hourly soundings used for validation. The GCE model simulated rainfall and latent heating profiles are in excelle nt agreement with those estimated by soundings. In addition, the typical co nvective and stratiform heating structures (or shapes) are well captured by the GCE model. Radar measured rainfall is smaller than that estimated by t he GCE model and SSM/I in both December convective episodes. SSM/I derived rainfall is more than the GCE model simulated for the December 19-27 and Fe bruary 9-13 periods, but it is in excellent agreement with the GCE model fo r the December 10-17 period. The GCE model estimated stratiform amount is a bout 50 % for December 19-27, 42 % for December 11-17 and 56 % for the Febr uary 9-13 case. These results are consistent with large-scale analyses. Acc urate estimates of stratiform amount are needed for good latent heating ret rieval. A higher (lower) percentage of stratiform rain can imply a maximum heating rate at a higher (lower) altitude. The GCE model always simulates m ore stratiform rain (10 to 20 %) than the radar for all three convective ep isodes. The SSM/I derived stratiform amount is about 37 % for December 19-2 7, 48 % for December 11-17 and 41 % for the February 9-13 case. Temporal variability of CSH algorithm retrieved latent heating profiles usi ng either the GCE model simulated or radar estimated rainfall and stratifor m amount is in good agreement with that diagnostically determined for all t hree periods. However, less rainfall and a smaller stratiform percentage es timated by radar resulted in a weaker (underestimated) latent heating profi le, and a lower maximum latent heating level compared to those determined d iagnostically. Rainfall information from SSM/I can not retrieve individual convective events due to poor temporal sampling. Nevertheless, this study s uggests that a good rainfall retrieval from SSM/I for a convective event ca n lead to a good latent heating retrieval. Sensitivity testing has been performed and the results indicate that the SS M/I derived time averaged stratiform amount may be underestimated for Decem ber 19-27. Time averaged heating profiles derived from SSM/I, however, agre e well with those derived by soundings for the December 10-17 convective pe riod. The heating retrievals may be more accurate for longer time scales, p rovided there is no bias in the sampling. An appropriate selection of latent heating profiles from the CSH look-up ta ble is important. Sensitivity tests addressing this issue have been perform ed.