scholarly journals Implementing a physical initialization procedure in a regional spectral model: impact on the short-range rainfall forecasting over South America

2004 ◽  
Vol 56 (2) ◽  
pp. 125-140 ◽  
Author(s):  
A. M. B. NUNES ◽  
S. COCKE
Keyword(s):  
South America ◽  
Short Range ◽  
Spectral Model ◽  
Rainfall Forecasting ◽  
Regional Spectral Model ◽  
Physical Initialization ◽  
Initialization Procedure

scholarly journals The Brazilian Global Atmospheric Model (BAM): Performance for Tropical Rainfall Forecasting and Sensitivity to Convective Scheme and Horizontal Resolution

2016 ◽  
Vol 31 (5) ◽  
pp. 1547-1572 ◽  
Author(s):  
Silvio N. Figueroa ◽  
José P. Bonatti ◽  
Paulo Y. Kubota ◽  
Georg A. Grell ◽  
Hugh Morrison ◽  
...  
Keyword(s):  
South America ◽  
Weather Prediction ◽  
Atmospheric Model ◽  
Horizontal Resolution ◽  
Southeastern Brazil ◽  
Rainfall Forecasting ◽  
Dynamical Core ◽  
Tropical Rainfall ◽  
Global Atmospheric Model ◽  
Convective Scheme

Abstract This article describes the main features of the Brazilian Global Atmospheric Model (BAM), analyses of its performance for tropical rainfall forecasting, and its sensitivity to convective scheme and horizontal resolution. BAM is the new global atmospheric model of the Center for Weather Forecasting and Climate Research [Centro de Previsão de Tempo e Estudos Climáticos (CPTEC)], which includes a new dynamical core and state-of-the-art parameterization schemes. BAM’s dynamical core incorporates a monotonic two-time-level semi-Lagrangian scheme, which is carried out completely on the model grid for the tridimensional transport of moisture, microphysical prognostic variables, and tracers. The performance of the quantitative precipitation forecasts (QPFs) from two convective schemes, the Grell–Dévényi (GD) scheme and its modified version (GDM), and two different horizontal resolutions are evaluated against the daily TRMM Multisatellite Precipitation Analysis over different tropical regions. Three main results are 1) the QPF skill was improved substantially with GDM in comparison to GD; 2) the increase in the horizontal resolution without any ad hoc tuning improves the variance of precipitation over continents with complex orography, such as Africa and South America, whereas over oceans there are no significant differences; and 3) the systematic errors (dry or wet biases) remain virtually unchanged for 5-day forecasts. Despite improvements in the tropical precipitation forecasts, especially over southeastern Brazil, dry biases over the Amazon and La Plata remain in BAM. Improving the precipitation forecasts over these regions remains a challenge for the future development of the model to be used not only for numerical weather prediction over South America but also for global climate simulations.

Experimental Weekly to Seasonal U.S. Forecasts with the Regional Spectral Model

2004 ◽  
Vol 85 (12) ◽  
pp. 1887-1902 ◽  
Author(s):  
J. Roads
Keyword(s):  
Spectral Model ◽  
Planetary Boundary Layer Height ◽  
Forecast System ◽  
Global Spectral Model ◽  
Layer Height ◽  
Boundary Layer Height ◽  
Regional Spectral Model ◽  
Environmental Prediction ◽  
Climate Prediction Center ◽  
Regional Forecast

Since 27 September 1997, the Scripps Experimental Climate Prediction Center (ECPC) has been making near real-time experimental global and regional dynamical forecasts with the National Centers for Environmental Prediction (NCEP) global spectral model (GSM) and the corresponding regional spectral model (RSM), which is based on the GSM, but which provides higher-resolution simulations and forecasts for limited regions. The global and regional forecast skill of the GSM was previously described in several papers. The purpose of this paper is to describe the RSM-based U.S. regional forecast system, various biases and errors in these regional U.S. forecasts, as well as the significant skill of the of temperature, precipitation, soil moisture, relative humidity, wind speed, and planetary boundary layer height forecasts at weekly to seasonal time scales. The skill of these RSM forecasts is comparable to the skill of the GSM forecasts.

scholarly journals Downscaling dinâmico de precipitação e veranicos no estado do Ceará

2017 ◽  
Vol 2 (4) ◽  
pp. 385-393
Author(s):  
José Brabo Alves ◽  
Emerson Mariano da Silva ◽  
Cláudia Patrícia Rickes
Keyword(s):  
Spectral Model ◽  
Regional Spectral Model

A região semiárida do Nordeste do Brasil (NEB) é conhecida por ser uma região extremamente oscilante do ponto de vista climático, devido à variabilidade temporal e espacial da precipitação. O objetivo desse estudo foi analisar a variabilidade intrassazonal e interanual das precipitações, através de veranicos, no Estado do Ceará. Esse comportamento é influenciado diretamente pela Temperatura da Superfície do Mar (TSM) dos oceanos Pacífico e Atlântico. O Regional Spectral Model RSM97, associado com a técnica de downscaling dinâmico, para quantificar as variações usando eventos de veranicos (dias consecutivos com precipitações abaixo de 2 mm que se sucedem durante a estação chuvosa do Estado), no período de 1974 a 2012, através de dados diários de precipitação da FUNCEME, de simulações de modelo numérico atmosférico e das anomalias de TSM (fases do ENOS). Os resultados foram apresentados em duas etapas, primeiro modo diagnóstico (com anomalias de TSM observadas de 1974 a 2000) e o segundo modo prognóstico (com anomalias de TSM persistidas de 2002 a 2012. Conclui-se que o uso do modelo RSM97, na previsão de períodos de estiagem durante a quadra chuva, tem algum potencial, em grande parte dos resultados o modelo subestimou o número de veranicos em relação aos observados, porém representou o sinal das observações dos eventos o que indica que suas características físicas influenciaram em quantificar a precipitação e sua distribuição espacial no Estado.

scholarly journals RainCast: A Rapid Update Rainfall Forecasting System for New Zealand

2021 ◽  
Author(s):  
Sijin Zhang ◽  
Gerard Barrow ◽  
Iman Soltanzadeh ◽  
Graham Rye ◽  
Yizhe Zhan ◽  
...  
Keyword(s):  
New Zealand ◽  
Numerical Weather Prediction ◽  
Short Range ◽  
Weather Prediction ◽  
Rainfall Forecasting ◽  
Numerical Weather ◽  
Forecasting System

Abstract RainCast is a rapid update forecasting system that has been developed to improve short-range rainfall forecasting in New Zealand. This system blends extrapolated nowcast information with multiple forecasts from numerical weather prediction (NWP) models to generate updated rain forecasts every hour. It is demonstrated that RainCast is able to outperform the rainfall forecasts produced from NWP systems out to 24 hours, with the greatest improvement in the first 3-4 hours. The limitations of RainCast are also discussed, along with recommendations on how to further improve the system.

scholarly journals The Taiwan Central Weather Bureau Regional Spectral Model for Seasonal Prediction: Multiparallel Implementation and Preliminary Results

2003 ◽  
Vol 131 (8) ◽  
pp. 1832-1847 ◽  
Author(s):  
Hann-Ming Henry Juang ◽  
Chih-Hui Shiao ◽  
Ming-Dean Cheng
Keyword(s):  
Message Passing ◽  
Message Passing Interface ◽  
Spectral Model ◽  
Model Structure ◽  
Lateral Boundary ◽  
Global Spectral Model ◽  
Weather Bureau ◽  
Structure Dynamics ◽  
Regional Spectral Model ◽  
Central Weather Bureau

Abstract A regional spectral model (RSM) is developed at the Taiwan Central Weather Bureau (CWB). It is based on the same model structure, dynamics, and physics of the CWB global spectral model (GSM) and the perturbation concept of the National Centers for Environmental Prediction (NCEP) RSM for lateral boundary treatment. The advantages of this new regional model include minimization of possible inconsistency between GSM and RSM through lateral boundary influence and reduction of resources used to manage and maintain the model. One-dimensional decomposition is utilized to slice the model into subdomains to run on a massive parallel-processor machine. The Message-Passing Interface (MPI) is adopted to communicate among each subdomain. The computational dependency, such as the summation in spectral transformation, is a restriction for the decomposition, so that the reproducibility using different numbers of processors is achieved. The performance in terms of wall-clock time follows the theoretical curve of parallelization. It can reach 95% parallelization by “homemade” PC Linux cluster, and 90% by CWB Fujitsu VPP5000. One case is selected to perform 2-month integration in a simulation mode and a forecast mode. The results indicate a reasonable monsoon frontal evolution as compared with analysis, and it has similar or less root-mean-square error (rmse) as compared to that of CWB GSM. The same run with NCEP RSM nested into CWB GSM shows a larger rmse than CWB RSM; it demonstrates the advantage of having the same model structure, dynamics, and physics between CWB GSM and CWB RSM.

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