Precipitation and Convective Statistics in the Trades: Observations, Simulation and Parameterization

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Within the "Rain in Cumulus over the Ocean" (RICO) experiment, this investigator will use measurements from a research radar and an instrumented aircraft to characterize the mesoscale and climate-scale properties of fields of trade-wind Cumuli. In contrast to most previous studies that have relied either on analyses of budgets or on in situ observations, this study will combine remote sensing and in situ measurements in order to characterize entire fields of clouds. The result will be a climatologically meaningful data set with supplementary detailed documentation of properties of the cloud fields in a few representative cases. The scientific goals are: (i) to determine statistically meaningful characteristics of trade-wind Cumuli and variations in those characteristics attributable to large-scale forcing (e.g., caused by passing weather systems); (ii) to determine if models, especially those that rely upon large-eddy-simulation, can reproduce and explain those variations; and (iii) to investigate the influence of precipitation on the measured properties of the cloud fields. The project thus seeks to use the detailed studies of individual clouds to be conducted in RICO to determine the ensemble properties of such clouds, needed if the influence of such cloud fields are to be incorporated into mesoscale and climate models. The expected result is improved understanding of the transport of moisture, energy, and momentum by trade-wind clouds and better knowledge of how to represent those effects in weather and climate systems. The project will also contribute to the training of graduate students and postdoctoral scientists in this area of research, both through their direct involvement in this project and through the RICO graduate-student seminar series. Another expected broader impact is the development of a benchmark data set against which models of tradewind Cumuli will be tested in this and future studies. This should be an important step toward better representation of the ensemble characteristics of these important tropical regions in climate models.