Open AccessSimulation of anomalous regional climate events with a variable‐resolution stretched‐grid GCM
Author(s) -
FoxRabinovitz Michael S.
Publication year - 2000
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jd900650
Subject(s) - downscaling , grid , climatology , precipitation , gcm transcription factors , variable (mathematics) , climate model , nested set model , environmental science , meteorology , flood myth , general circulation model , climate change , geology , computer science , geography , mathematics , geodesy , data mining , mathematical analysis , oceanography , archaeology , relational database
The stretched‐grid approach provides an efficient downscaling and consistent interactions between global and regional scales due to using one variable‐resolution model for integrations. It is a workable alternative to the widely used nested‐grid approach introduced over a decade ago as a pioneering step in regional climate modeling. A variable‐resolution finite‐difference GCM (general circulation model) employing a stretched grid, with enhanced resolution over the United States as the area of interest, is used for simulating two anomalous regional climate events, the U.S. summer drought of 1988 and the U.S. summer flood of 1993. The special mode of integration using a stretched‐grid GCM and data assimilation system is developed which allows for imitating the nested‐grid framework within a stretched‐grid approach. The mode is useful for intercomparison purposes and for underlining the differences between these two approaches. The 1988 and 1993 integrations are performed for the 2 month period starting from mid‐May. Regional resolutions used in most of the experiments is 60 km. The major goal and the result of the study is obtaining the efficient downscaling over the area of interest. The monthly mean prognostic regional fields for the stretched‐grid integrations are remarkably close to those of the verifying analyses. Simulated precipitation patterns are successfully verified against gauge precipitation observations. The impact of finer 40 km regional resolution is investigated for the 1993 integration and an example of recovering subregional precipitation is presented. The obtained results show that the global variable‐resolution stretched‐grid approach is a viable candidate for regional and subregional climate studies and applications.