On the assimilation of TOVS data: a case study (original) (raw)

An Initial Assessment of Radar Data Assimilation on Warm Season Rainfall Forecasts for Use in Hydrologic Models

Weather and Forecasting, 2015

The effect of introducing radar data assimilation into the WRF Model to improve high-resolution rainfall forecasts that are used for flash flood forecasting is analyzed. The authors selected 12 heavy rainfall events and performed two WRF 24-h simulations that produced quantitative precipitation forecasts (QPFs) for each, one using the standard configuration in forecast mode (QPF-Cold) and one using radar data assimilated at initialization (QPF-Hot). Simulation outputs are compared with NWS stage IV QPEs for storm placement, area over threshold coverage, and equitable threat scores. The two QPF products and stage IV data are used to force the distributed hydrological model CUENCAS for the same 800 km × 800 km domain centered over Iowa (and to calculate peak flows across the river network). The hydrological model responses to the three products are compared in terms of spatial location and flood intensity. In general, QPF-Hot outperformed QPF-Cold in replicating stage IV QPE statistic...

Impact of radar data assimilation on WRF simulations of the Aniene flood

2010

A study of the Aniene flood, in the urban area of Rome, is performed using Monte Midia Radar data to improve high resolution initial conditions. The radar site is at the border between the Abruzzo and Lazio regions in Central Italy. Mt. Midia top height is at 1760 m and covering most Central Italy, including the urban area of Rome. Aniene flood occurred during May 20-22, 2008 causing severe damages. The meteorological structure was characterized by a deep cyclone impinging on the Tyrrhenian sea for almost two days. During the event radar detected either local convection northern of Rome and moderate rain east of Rome lasting for several hours. High resolution simulations using WRFV3 model are performed; to the aim of improving the Initial Conditions radar data have been assimilated using 3DVAR. Sensitivity tests to different set of Initial Conditions are performer using either ECMWF analyses and ‘warm start'. Moreover, ‘ad hoc' radar reflectivity coefficients for the Monte Midia radar have been used to analyze their impact in the model forecast. Finally, to objectively identify the best IC statistical indicators are used as FBIAS, RMS and EQTS for the accumulated precipitation.