Precipitable Water Vapor: The Critical Variable in Tropical Deep Convection

David K. Adams

Center for Atmospheric Science National University of Mexico

Friday, Mar 30, 2018, 11:00 am
DSRC Room 1D708

Abstract

Column, or precipitable water vapor (PWV), has been shown to be strongly tied to deep convective precipitation in the Tropics, thereby providing a useful variable for understanding convective/large-scale interactions. Both theory for these interactions, as well as their parameterization in coarse-resolution models, have employed either PWV, or some variant (e.g., column relative humidity) as the critical variable. Furthermore, given its simplicity to calculate, PWV can also provide a useful variable for models of all resolutions to evaluate model realism. GPS meteorology has provided high frequency (~5 minutes), all weather PWV for nearly two decades. However, the use of GPS PWV in deep tropical regions has been rather limited; this being particularly surprising given the need for tropical continental counterparts to the vastly more numerous maritime-based studies. I will present results from a long-term GPS site as well as a dense network in the Central Amazon, focusing on the use of GPS PWV to derive metrics for the problematic shallow-to-deep convective transition. I will then critically examine the column water vapor criticality theory (Neelin and colleagues) as seen with GPS PWV for this same region and then close with a brief overview of our GPSmet component in the Organization of Tropical East Pacific Convection (OTREC) 2019 field campaign.