Lagrangian Diagnostics of Tropical Cirrus over TWP CART Sites
| Horvath, Akos | University of Miami |
| Soden, Brian | UM/RSMAS |
Category: Cloud Properties
Cirrus clouds associated with tropical deep convection play an important role in regulating Earth's climate by influencing the radiative and moisture budgets of the upper troposphere. In this study, we sought to better understand the evolution of such clouds using geostationary satellite observations coupled with ground-based radar and lidar measurements at ARM TWP CART sites. Using geostationary imagery from the MTSAT satellite we constructed Lagrangian composites of cirrus cloud evolution by tracking radiance patterns from successive images. Specifically, we tracked, both forward and backward in time, a 200km x 200km reference pattern centered at the CART site using cross-correlations. The end product of our tracking algorithm was a Lagrangian data base of cloud trajectories and associated cloud properties documenting the origin, evolution, and decay of the passing cloud systems. We obtained cloud properties (such as optical thickness, effective radius, and ice water path) from the VISST/SIST algorithm developed by the NASA Langley Cloud and Radiation Research Group (Minnis Group). We then used these satellite measurements to composite the Eulerian CART cloud property retrievals as a function of Lagrangian cloud characteristics (e.g., age) in order to study the life cycle of cloud microphysical, macrophysical, and radiative properties. The proposed poster details the methodology behind our automated cloud tracking algorithm, and presents a preliminary statistical summary of the evolution of cirrus properties and their effects upon the downstream upper tropospheric humidity (UTH), particularly the correlation between ice water path and UTH.
This poster will be displayed at the ARM Science Team Meeting.
