Cloud microphysical properties in contrasting monsoon days as revealed by CAIPEEX and MODIS observation and by cloud permitting WRF simulation
Abstract
It is understood that the problem in the present day general circulation model is arising from the deficiency of representation of cloud processes. This is attributed to unavailability of a good time series of observational data at cloud scales. One such issue is addressed in the “Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX)”, over the Indian region during May-Sep, 2009. The objective of this paper is to bring out the microphysics of clouds during two contrasting days of Indian Summer Monsoon (ISM) based on flight data of the CAIPEEX as well as from the satellite observations over the region of Central India (CI). The paper also intends to see to what extent the WRF-ARW simulation at cloud permitting resolution (9-3 km), could capture the cloud types and properties. The rainfall observation on July 15 and August 18, 2009 suggests respectively an active and suppressed monsoon convection over CI. A flight data could bring out only the cloud observations along its path, the other cloud properties about the types of clouds (low, middle, high) during these two days are derived from the MODIS data. The large scale atmospheric conditions, are represented by the NCEP/NCAR reanalyses. Analyses of clouds on July 15, 2009 (Fig. 1a), reveals that the clouds from south to north over the chosen domain is distributed starting from deep through middle level to high level clouds. The variation of CCN concentration (from CAIPEEX) also supports the nature of clouds present. Simultaneously when the WRF model simulation is performed, it is found that the model could show deep clouds over lower latitude however fail to reproduce the middle and higher level clouds (Fig 1b). Analysis of Aug 18 ,2009, simulation also reveals an equivalent results. Hence it can be said that during an active or break phase of monsoon, significant heterogeneity exists in cloud distribution and types. The WRF simulation is able to capture some of the observed features of the cloud but could not simulate the middle and high level clouds. Thus a suitable modification in microphysical scheme needs to be done to improve such model biases which in turn would improve the forecast of cloud life cycle vis-à-vis precipitation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.A23A0204C
- Keywords:
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- 3311 ATMOSPHERIC PROCESSES / Clouds and aerosols