Quantifying the Contribution of Different Cloud Types to the Radiation Budget in Southern West Africa

The contribution of cloud to the radiation budget of southern West Africa (SWA) is poorly understood and yet it is important for understanding regional monsoon evolution and for evaluating and improving climate models, which have large biases in this region. Radiative transfer calculations applied t...

Full description

Saved in:
Bibliographic Details
Published in:Journal of climate 2018-07, Vol.31 (13), p.5273-5291
Main Authors: Hill, Peter G., Allan, Richard P., Chiu, J. Christine, Bodas-Salcedo, Alejandro, Knippertz, Peter
Format: Article
Language:English
Subjects:
Atmosphere
Atmospheric cooling
Atmospheric models
Budgets
Climate
Climate models
Cloud cover
Cloud types
Clouds
Datasets
Downwelling
Energy budget
Evolution
Heating
Irradiance
Low clouds
Meteorological satellites
Monsoons
Ocean circulation
Precipitation
Profiles
Radiation
Radiation budget
Radiative cooling
Radiative transfer
Radiative transfer calculations
Rain
Regional analysis
Satellite observation
Satellites
Short wave radiation
Simulation
Studies
Upwelling
Vertical profiles
Wind
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The contribution of cloud to the radiation budget of southern West Africa (SWA) is poorly understood and yet it is important for understanding regional monsoon evolution and for evaluating and improving climate models, which have large biases in this region. Radiative transfer calculations applied to atmospheric profiles obtained from the CERES–CloudSat–CALIPSO–MODIS (CCCM) dataset are used to investigate the effects of 12 different cloud types (defined by their vertical structure) on the regional energy budget of SWA (5°–10°N, 8°W–8°E) during June–September. We show that the large regional mean cloud radiative effect in SWA is due to nonnegligible contributions from many different cloud types; eight cloud types have a cloud fraction larger than 5% and contribute at least 5% of the regional mean shortwave cloud radiative effect at the top of the atmosphere. Low clouds, which are poorly observed by passive satellite measurements, were found to cause net radiative cooling of the atmosphere, which reduces the heating from other cloud types by approximately 10%. The sensitivity of the radiation budget to underestimating low-cloud cover is also investigated. The radiative effect of missing low cloud is found to be up to approximately –25 W m−2 for upwelling shortwave irradiance at the top of the atmosphere and 35 W m−2 for downwelling shortwave irradiance at the surface.
ISSN:0894-8755
1520-0442
DOI:10.1175/JCLI-D-17-0586.1