Tests of a Convective Cloud Model with Soundings During the TCM-90 Field Experiment
Abstract
A new proposed scheme for representing cumulus convection in a large- scale numerical model has been tested using the dataset collected during the Tropical Cyclone Motion (TCM-90) field experiment. This new scheme by K. Emanuel incorporated some modifications, which are based on recent observations of convective clouds, and showed much of the vertical transport of convective clouds was accomplished by subcloud-scale drafts rather than by the clouds themselves. These small-scale drafts were idealized ana regarded as the fundamental agents of the convective transport. The input to the idealized model of subcloud--scale updrafts and downdrafts is the one-dimensional arrays of temperature and mixing ratio as a function of pressure, and the output is the tendency of potential temperature and the tendency of mixing ratio as well as the rate of convective precipitation. In this test, 46 dropwindsondes from the TCM-90 dataset with a vertical resolution of 10 mb were chosen as inputs. The convection scheme is integrated in time to investigate the outputs of precipitation rates. The model was forced with constant radiative cooling, convective heating/and moistening calculated from model and surface fluxes in all cases. We conclude that this new modified convective scheme predicts quite reasonable precipitation rates in the regions beyond 4 degree latitude radius, but not near the center (too small) of Supertyphoon Flo on 16, 17 and 18 September 1990.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1992
- Accession Number
- ADA253069
Entities
People
- Yin Tzy-chyang
Organizations
- Naval Postgraduate School