Search

The impact of GPS zenith total delay (ZTD) measurements on mesoscale weather forecasts is studied. GPS observations from a permanent European network are assimilated into the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) using its three-dimensional variational data assimilation (3DVAR) system. The case study focuses on a snow storm that occurred during the period of 14–15 December 2001 over the western Mediterranean Sea. The experiments show that the most significant improvement in forecast is obtained when GPS ZTD data are assimilated together with local surface meteorological observations into the model within a cycling assimilation framework. In this case, the root-mean-square (rms) differences between forecasted and observed values are reduced by 1.7% in the wind component, 4.1% in the temperature variable, and 17.8% in the specific humidity field. This suggests the deployment of GPS receivers at surface stations to better initialize numerical weather prediction models during strong storm mesoscale events. [ABSTRACT FROM AUTHOR]

The specification of state background error statistics is a key component of data assimilation since it affects the impact observations will have on the analysis. In the variational data assimilation approach, applied in geophysical sciences, the dimensions of the background error covariance matrix (B) are usually too large to be explicitly determined and B needs to be modeled. Recent efforts to include new variables in the analysis such as cloud parameters and chemical species have required the development of the code to GENerate the Background Errors (GEN_BE) version 2.0 for the Weather Research and Forecasting (WRF) community model. GEN_BE allows for a simpler, flexible, robust, and community-oriented framework that gathers methods used by some meteorological operational centers and researchers. We present the advantages of this new design for the data assimilation community by performing benchmarks of different modeling of B and showing some of the new features in data assimilation test cases. As data assimilation for clouds remains a challenge, we present a multivariate approach that includes hydrometeors in the control variables and new correlated errors. In addition, the GEN_BE v2.0 code is employed to diagnose error parameter statistics for chemical species, which shows that it is a tool flexible enough to implement new control variables. While the generation of the background errors statistics code was first developed for atmospheric research, the new version (GEN_BE v2.0) can be easily applied to other domains of science and chosen to diagnose and model B. Initially developed for variational data assimilation, the model of the B matrix may be useful for variational ensemble hybrid methods as well. [ABSTRACT FROM AUTHOR]

Summary: Background: Indirect inguinal hernia (IIH) is the most commonly reported acquired hernia in adult horses. Outcomes following surgical intervention comprising of immediate ventral midline laparotomy (IVML) and simultaneous castration are well known. The outcome following reduction of IIH utilising a noninvasive manual reduction (MR) technique in a large number of horses has not been previously reported. Objectives: To describe a nonsurgical MR technique developed by the authors and to report our long‐term experiences and clinical outcome. Study design: Retrospective study. Methods: Medical records of 89 stallions presenting with IIH and treated with MR were reviewed. Extensive patient data was collected, with cases grouped based on outcome of the MR procedure and whether or not laparotomy was performed. Data on short‐ and long‐term outcome was obtained. Results: Manual reduction was successful in 80 of 89 (90%) horses. Fifty of 89 (56%) horses were treated with MR only and without exploratory laparotomy. In total 29 of 89 (33%) horses underwent IVML and 10 of 89 (11%) delayed ventral midline laparotomy (DVML). Resections were performed in 6 of 89 (8%) horses. Concurrent small intestinal volvulus was diagnosed in 8 of 89 (9%) horses. Horses undergoing DVML following a successful MR had the highest mortality rates during hospitalisation (4/10, 40%). Short‐term survival was 92% (82/89). Ipsilateral reoccurrence of IIH post‐hospital discharge was recorded in 7 of 47 (15%) horses. Overall long‐term survival with a median of 12 years was 72% (34/47). Main limitations: These include the retrospective nature of data collection, lack of standardised pre‐ and post‐MR clinical assessments and a biased Warmblood population. Conclusions: Manual reduction appears to be a feasible nonsurgical technique to reduce IIH in adult Warmblood horses, with favourable survival rates. Individual case assessment is crucial, as delayed laparotomy may increase mortality rates. Suspicion of concurrent small intestinal volvulus or devitalised small intestine always warrants immediate laparotomy following MR. [ABSTRACT FROM AUTHOR]

Short-period (1–5 min) temperature and humidity soundings up to 10-km height are retrieved from ground-based 12-channel microwave radiometer profiler (MWRP) observations. In contrast to radiosondes, the radiometric retrievals provide very high temporal resolution (1 min or less) of thermodynamic profiles, but the vertical resolution, which declines in proportion to the height above ground level, is lower. The high temporal resolution is able to resolve detailed meso-γ-scale thermodynamic and limited microphysical features of various rapidly changing mesoscale and/or hazardous weather phenomena. To illustrate the MWRP capabilities and potential benefits to research and operational activities, the authors present example radiometric retrievals from a variety of dynamic weather phenomena including upslope supercooled fog, snowfall, a complex cold front, a nocturnal bore, and a squall line accompanied by a wake low and other rapid variations in low-level water vapor and temperature. [ABSTRACT FROM AUTHOR]