Scientific Results

  • ID:
    publications-2650
  • Type:
    Peer reviewed articles
  • Year:
    2017
  • Authors:
    A. Orr, C. Listowski, M. Couttet, E. Collier, W. Immerzeel, P. Deb, D. Bannister
  • Title:
    Sensitivity of simulated summer monsoonal precipitation in Langtang Valley, Himalaya, to cloud microphysics schemes in WRF
  • Venue/Journal:
    Journal of Geophysical Research: Atmospheres
  • DOI:
    10.1002/2016JD025801
  • Research type:
    Data Management & Analytics
  • Water System:
    Water Distribution Networks
  • Technical Focus:
  • Abstract:
    AbstractA better understanding of regionalā€scale precipitation patterns in the Himalayan region is required to increase our knowledge of the impacts of climate change on downstream water availability. This study examines the impact of four cloud microphysical schemes (Thompson, Morrison, Weather Research and Forecasting (WRF) singleā€moment 5ā€class, and WRF doubleā€moment 6ā€class) on summer monsoon precipitation in the Langtang Valley in the central Nepalese Himalayas, as simulated by the WRF model at 1Ā km grid spacing for a 10Ā day period in July 2012. The model results are evaluated through a comparison with surface precipitation and radiation measurements made at two observation sites. Additional understanding is gained from a detailed examination of the microphysical characteristics simulated by each scheme, which are compared with measurements using a spaceborne radar/lidar cloud product. Also examined are the roles of largeā€ and smallā€scale forcings. In general, the schemes are able to capture the timing of surface precipitation better than the actual amounts in the Langtang Valley, which are predominately underestimated, with the Morrison scheme showing the best agreement with the measured values. The schemes all show a large positive bias in incoming radiation. Analysis of the radar/lidar cloud product and hydrometeors from each of the schemes suggests that ā€œcoldā€rainā€ processes are a key precipitation formation mechanism, which is also well represented by the Morrison scheme. As well as microphysical structure, both largeā€scale and localized forcings are also important for determining surface precipitation.
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    676819
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