Apr 10, 2016

Cloud Cover on the surface net radiation

Solar radiation is the key  driving force for water cycle. It modulates how much water land surface evaporates and plant transpires. The  explicitly estimation of  radiation is essential for water budget modelling. One of the major factor affect the net surface radiation is the cloud cover. It can affect the net radiation in many ways.  The influence of cloud on the land surface energy depends on several factors, such as cloud altitude, it size, the nature of the cloud particles.

Due to the lack of accurate cloud cover information, the  net radiation modelling thereby the processes of  land-atmosphere interaction is poorly characterised. Some spatial cloud cover data, as given by recent satellite imagery, however, can contribute for better estimation of the basin water budget simulation.  For effort in this direction, EUMETSAT Climate Monitoring Satellite Application Facility (CM SAF) cloud cover fraction data can be useful resource. Here I have processed this data for Upper Blue Nile basin to be used in water budget modelling. A sample of the monthly mean could cover map over the basin for the 1994 is shows in figure 1.

The seasonality of the cover can be clearly seen, and this contributes to the reason for  governing factors of  the seasonality in the basin  water budget.  

Some papers on cloud and hydrology 

Cawkwell, F. G. L., and J. L. Bamber. "The impact of cloud cover on the net radiation budget of the Greenland ice sheet." Annals of Glaciology 34.1 (2002): 141-149.

Alados, I., et al. "Relationship between net radiation and solar radiation for semi-arid shrub-land." Agricultural and Forest Meteorology 116.3 (2003): 221-227.

Frank Richards and Phil Arkin , 2009: On the Relationship between Satellite-Observed Cloud Cover and Precipitation. Monthly Weather Review109, 1081–1093, doi: 10.1175/1520-0493(1981)109<1081:OTRBSO>2.0.CO;2.

J. A. Griggs and J. L. Bamber , 2010: Assessment of Cloud Cover Characteristics in Satellite Datasets and Reanalysis Products for Greenland. Journal of Climate21, 1837–1849, doi: 10.1175/2007JCLI1570.1.

to be updated….