An Airborne Remote Sensing Perspective on Cloud and Precipitation Properties from Southeast Atlantic Stratocumulus Clouds PDF Download

Author: Andrew Michael Dzambo
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

Get Book

Book Description
Stratocumulus (StCu) clouds cover a majority of the Earth's subtropical oceanic basins, and play an important role in the global energy balance. Cloud and precipitation processes in StCu are complex, and aerosol effects add further complexity to the cloud-precipitation-climate paradigm, where these interactions are among the most widely uncertain processes in present-day climate models. The NASA ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field campaign between 2016-18 observed cloud-aerosol-precipitation interactions over the Southeast Atlantic Ocean. One of the 20+ instruments deployed during ORACLES was the Airborne Precipitation Radar - 3rd Generation (APR-3). The APR-3 collected over 18 million profiles during the three deployments. A precipitation retrieval algorithm (called 2C-RAIN) was adapted from the CloudSat 2C-RAIN-PROFILE precipitation retrieval algorithm to meet ORACLES science objectives. The majority of 2C-RAIN precipitation rates were under 0.01 mm/hr (0.25 mm/day). The sampling environments were considerably different in 2016 compared to 2017 and 2018, necessitating further investigation accounting for environmental controls. Cloud water path (CWP) retrievals were added to the 2C-RAIN algorithm. This retrieval expanded the utility of APR-3 measurements by collocating cloud and precipitation properties (namely CWP and RWP) for the investigation of aerosol indirect effects. This work find typical CWP to RWP ratios on the order of 50:1 to 200:1, implying CWP dominates the total liquid water path (LWP) signal. When partitioning rain rates with CWP and RWP for aerosol contact and non-contact cases, statistically significant differences are found in stable environments for CWP/RWP but not for retrieved rain rates, likely owing to the 100% and larger uncertainties associated with precipitation rate retrievals. Finally, evaporation processes are investigated between drizzling virga and surface precipitation. Evaporation rates/fluxes and corresponding latent cooling rates, between surface precipitation and virga, are on the order of 2:1 implying that surface precipitation contributes the most latent cooling to the local environment. Evaporating virga, regardless, cannot be ignored when studying latent heating and cooling. The development of the 2C-RAIN database for ORACLES, and analyses presented here, pave the way for additional observation-based studies in an area where satellite measurements have limited viability.