Extended Abstract (216K)JP1.17
The impact of ground-based GPS slant-path wet delay measurements on short-range prediction of a prefrontal squall line
So-Young Ha, School of Earth and Environmental Sciences, Seoul, Korea, and NCAR, Boulder, CO; and Y. H. Kuo and G. H. Lim
With the recent advance of Global Positioning System (GPS) sensing technology, ground-based GPS slant-path wet delay measurements provide an opportunity to observe the small-scale variation of the low-level atmospheric moisture at high temporal resolution. In this study, we performed a series of observing system simulation experiments to assess the potential impact of slant wet delay on the prediction of a prefrontal squall line. The slant wet delay measurements were assimilated through four-dimensional variational data assimilation (4DVAR). We found that the assimilation of slant wet delay data resulted in the enhancement of the three-dimensional gradient of thermodynamic fields in the boundary layer and intensified the surface cold front. As a result, a significant improvement was achieved on the 6-h forecast of the squall line in terms of rainfall prediction and the retrieval of the atmospheric structure.
Joint Poster Session 1, Spatial and Temporal Variability (Joint with the Symposium on Observing and Understanding the Variability of Water in Weather and Climate and the 17th Conference on Hydrology)
Monday, 10 February 2003, 2:30 PM-2:30 PM
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