Satellite Data Assimilation in Numerical Weather Prediction Models. Part II: Uses of Rain-Affected Radiances from Microwave Observations for Hurricane Vortex Analysis

Abstract

A hybrid variational scheme (HVAR) is developed to produce the vortex analysis associated with tropical storms. This scheme allows for direct assimilation of rain-affected radiances from satellite microwave instruments. In the HVAR, the atmospheric temperature and surface parameters in the storms are derived from a one-dimension variational data assimilation (1DVAR) scheme, which minimizes the cost function of both background information and satellite measurements. In the minimization process, a radiative transfer model including scattering and emission is used for radiance simulation (see Part I of this study). Through the use of 4DVAR, atmospheric temperatures from the Advanced Microwave Sounding Unit (AMSU) and surface parameters from the Advanced Microwave Scanning Radiometer (AMSR-E) are assimilated into global forecast model outputs to produce an improved analysis. This new scheme is generally applicable for variable stages of storms. In the 2005 hurricane season, the HVAR was applied for two hurricane cases, resulting in improved analyses of three-dimensional structures of temperature and wind fields as compared with operational model analysis fields. It is found that HVAR reproduces detailed structures for the hurricane warm core at the upper troposphere. Both lower-level wind speed and upper-level divergence are enhanced with reasonable asymmetric structure.

Uncertainties in Microwave Properties of Frozen Precipitation: Implications for Remote Sensing and Data Assimilation

“…Cloud and precipitation research has particularly benefited from sustained microwave observations that have enabled the development and continual improvement of global cloud and precipitation climatologies (e.g., Weng et al 1997;O'Dell et al 2008;Hilburn and Wentz 2008;Liu and Zipser 2009;Ellis et al 2009). Cloud and precipitation research has particularly benefited from sustained microwave observations that have enabled the development and continual improvement of global cloud and precipitation climatologies (e.g., Weng et al 1997;O'Dell et al 2008;Hilburn and Wentz 2008;Liu and Zipser 2009;Ellis et al 2009).…”

“…This topic has received considerable attention in recent years owing to the valuable information content contained in microwave observations that increases forecast skill (e.g., English et al 2000;Mahfouf et al 2005;Weng et al 2007;Kelly et al 2008). This topic has received considerable attention in recent years owing to the valuable information content contained in microwave observations that increases forecast skill (e.g., English et al 2000;Mahfouf et al 2005;Weng et al 2007;Kelly et al 2008).…”

Assimilating synthetic GOES-R radiances in cloudy conditions using an ensemble-based method

“…The two-step approach, where satellite radiances are assimilated by the non-linear 1D-Var step to produce increments of total column water vapour, and then these increments are assimilated Assimilating synthetic GOES-R radiances 9639 by the linear (so-called incremental) 4D-Var step, has proven better in handling non-linearities than the incremental 4D-Var approach alone. In Weng et al (2007) rain-affected satellite microwave radiances from the Advanced Microwave Sounding Unit (AMSU) and the Advanced Microwave Scanning Radiometer (AMSR-E) are assimilated to improve hurricane vortex analysis. They used an approach called hybrid variational (HVAR) scheme, which is similar to the ECMWF 1D-Var + 4D-Var approach; however, they employed a different model, the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) and its adjoint (Zou et al 1998, Zou andXiao 2000).…”

An Observing System Simulation Experiment for the Impact of MTG Candidate Infrared Sounding Mission on Regional Forecasts: System Development and Preliminary Results

“…For example, at the European Centre for Medium-Range Weather Forecasts (ECMWF), an all-sky approach [3] has been developed to assimilate Special Sensor Microwave/Imager (SSM/I) and Advanced Microwave Scanning Radiometer for the Earth Observing system (AMSR-E) data. At National Oceanic and Atmospheric Administration (NOAA), Weng et al [4] developed a hybrid variational scheme to use observations from the Advanced Microwave Sounding Unit (AMSU) instruments. Until recently, more attention has been directed towards cloud-resolving scale data assimilation.…”