Speaker
Description
This study investigates the role of rain evaporation in shaping cloud cover and influencing the energy and radiation budget in the trade cumulus region. Although research has advanced our understanding of shallow trade cumulus clouds, the influence of mesoscale cloud organization on cloud feedbacks and the hydrological cycle remains uncertain. Rain re-evaporation can drive mesoscale structures, generating downdrafts and cold pools that form cloud-free areas encircled by cloud arcs. Yet, the relationships between cold pool characteristics, initial rain evaporation, and their effects on cloud cover and the radiative budget are not well understood, largely due to limitations in observational data and model fidelity.
To address this gap, we will develop a long-term dataset of rain evaporation rates using measurements from the Barbados Cloud Observatory. By examining vertical differences in drop size distributions, we aim to characterize the vertical structure of rain evaporation and cooling rates. This work leverages a dual-frequency method with Ka-W band Doppler spectra, chosen for its capacity to address challenges related to attenuation, calibration, and turbulence. We will consider this dual-frequency retrieval as a "ground truth," using it to evaluate the reliability of other retrieval methods, including a single-frequency approach combined with a vertical velocity retrieval and an observationally-constrained one-dimensional rain shaft model. Observations from the ORCESTRA (Organized Convection and EarthCare Studies over the Tropical Atlantic) campaign and its SCORE (Sub-Cloud Observations of Rain Evaporation) sub-campaign will serve as intensive testing phases.
Ultimately, this dataset will enable quantification of the magnitude and vertical structure of rain evaporation, explore their dependence on ambient humidity and rain intensity, and assess the impact of evaporation profiles on boundary layer stability, cold pool dynamics, and cloudiness.
| Presenting Author | Nina Robbins-Blanch |
|---|---|
| Email Address of Presenting Author | nina.robbins.blanch@uni-hamburg.de |
| Affiliation of Presenting Author | Universität Hamburg |
| Address of Presenting Author | Bundestrasse 55, 20146, Hamburg |
| Session | From Classical to Integrated Remote Sensing: New observation strategies for clouds and precipitation (multi-frequency, spectral polarimetry, multi-sensor) |
| Preferred Contribution Type | Oral Presentation |
