Clear-Sky Turbulence and Shallow Convection: New Insights Combining SAR
Images, Satellite Brightness Temperature and In Situ Measurements
Abstract
The imprint of marine atmospheric boundary layer (MABL) dynamical
structures on sea surface roughness, as seen from Sentinel-1 Synthetic
Aperture Radar (SAR) acquisitions, is investigated. We focus on February
13th, 2020, a case study of the EUREC4A (Elucidating the role of
clouds-circulation coupling in climate) field campaign. For clear sky
conditions, convective rolls and cells imprints on sea surface roughness
is confirmed through the intercomparison with MABL turbulent
organization deduced from airborne measurements. A discretization of the
SAR wide swath into 25 x 25 km$^2$ tiles allows us to capture the
spatial variability of the turbulence organization varying from rolls to
cells. We then objectively detect cold pools within the SAR image and
combine them with geostationary brightness temperature. The geometrical
or physically-based metrics of cold pools are correlated to cloud
properties. This provides a promising methodology to analyze the
dynamics of convective systems as seen from below and above.