American Geophysical Union, Journal of Geophysical Research, D22(116), p. n/a-n/a, 2011
DOI: 10.1029/2011jd016029
Full text: Unavailable
The West African summer monsoon (WAM) is an important driver of the global climate and locally provides most of the annual rainfall. A solid climatological knowl-edge of the complex vertical cloud structure is invaluable to forecasters and modellers to improve the understanding of the WAM. In this paper, four years of data from the CloudSat profiling radar and CALIPSO lidar are used to create a composite zonal mean vertical cloud and precipitation structure for the WAM. For the first time, the near-coincident vertical radar and lidar profiles allow for the identification of individual cloud types from optically thin cirrus and shallow cumulus to congestus and deep convection. A clear di-urnal signal in zonal mean cloud structure is observed for the WAM, with deep convec-tive activity enhanced at night producing extensive anvil and cirrus, whilst daytime ob-servations show more shallow cloud and congestus. A layer of altocumulus is frequently observed over the Sahara at night and day, extending southward to the coastline, and the majority of this cloud is shown to contain supercooled liquid in the top. The occur-rence of deep convective systems and congestus in relation to the position of the African easterly jet is studied, but only the daytime cumulonimbus distribution indicates some influence of the jet position.