Evaluation of the Variability of the Precipitation under Orographic Conditions
Abstract
This study investigates the performance of the precipitation products derived from the Weather Research and Forecasting (WRF) model and the EUMETSAT Multi-sensor Precipitation Estimates (MPEs) over a region where orography is the dominant form of precipitation. WRF and MPE comparisons are made against 34 gauge-observed precipitation data obtained for 20 events that created floods over West Black Sea Region of Turkey. The stations are located at elevations range between 0 and 1270 m above mean sea level and stations have been grouped up based on elevation and distance from coastline to continent and their climatic precipitation response performance have been evaluated. Consistent with other studies, WRF model precipitation forecast errors related to model initial conditions are reduced when the three dimensional atmospheric data assimilation (3DVAR) scheme in the WRF model simulations is used. MPE and WRF precipitation estimates, both with and without data assimilation, are later validated using actual gauge-based observations. In the use of 3DVAR assimilation scheme improved WRF model precipitation estimates considerably. MPE precipitation estimates in general showed poor performance as a result of its dry bias. Maximum regional correlations have been estimated as 0.94 (WRF assimilated), 0.90 (WRF non-assimilated) and 0.63 (MPE) where the overall regional correlation means are 0.69 (WRF) and 0.49 (MPE). It has been also observed that on average WRF correlations decreased as the orographic effect of continental climate region getting more dominant over the study domain, where MPE correlations are increased and errors decreased as the sub-regions gets more continental at higher altitudes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.A31A2150O
- Keywords:
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- 3310 Clouds and cloud feedbacks;
- ATMOSPHERIC PROCESSES;
- 3354 Precipitation;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES;
- 1853 Precipitation-radar;
- HYDROLOGY