scholarly journals ACOPLAMENTO BRAMS-WW3 PARA PREVISÃO DE ONDAS OCEÂNICAS

2016 ◽  
Vol 38 ◽  
pp. 401
Author(s):  
Renata Sampaio da Rocha Ruiz ◽  
Rosio Del Pilar Camayo Maita ◽  
Haroldo Fraga de Campos Velho ◽  
Saulo Freitas ◽  
Valdir Innocentini
Keyword(s):  
South America ◽  
Wind Field ◽  
Weather Prediction ◽  
Circulation Model ◽  
Ocean Waves ◽  
Horizontal Resolution ◽  
Southeastern Brazil ◽  
Meteorological Model ◽  
Wavewatch Iii ◽  
Global Atmospheric Circulation

A version of the coupled ocean waves WaveWatch III (WW3) model with mesoscale meteorological model BRAMS is presented. The WW3 is a model for waves forecasting. The BRAMS model is used for numerical weather prediction over South America, with horizontal resolution of 5 km. Both models are executed operationally by the CPTEC-INPE. The boundary conditions for the BRAMS model are provided by the global atmospheric circulation model of the CPTEC-INPE. The simulation with BRAMS for14/Oct/2014 generated a wind field with better agreement with the observations (satellite Metop-A, ASCAT sensor) to the coast of southeastern Brazil) than the field wind generated by the SFM model. The simulation with wind field generated by BRAMS produces higher waves than ones predicted with GFS wind field.

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.

scholarly journals Effects of Increasing Horizontal Resolution in a Convection-Permitting Model on Flood Forecasting: The 2011 Dramatic Events in Liguria, Italy

2015 ◽  
Vol 16 (4) ◽  
pp. 1843-1856 ◽  
Author(s):  
Silvio Davolio ◽  
Francesco Silvestro ◽  
Piero Malguzzi
Keyword(s):  
High Resolution ◽  
Weather Prediction ◽  
Flood Forecasting ◽  
Horizontal Resolution ◽  
Precipitation Forecast ◽  
Limited Area ◽  
Flood Prediction ◽  
Meteorological Model ◽  
The Impact ◽  
Atmospheric Simulations

Abstract Coupling meteorological and hydrological models is a common and standard practice in the field of flood forecasting. In this study, a numerical weather prediction (NWP) chain based on the BOLogna Limited Area Model (BOLAM) and the MOdello LOCale in Hybrid coordinates (MOLOCH) was coupled with the operational hydrological forecasting chain of the Ligurian Hydro-Meteorological Functional Centre to simulate two major floods that occurred during autumn 2011 in northern Italy. Different atmospheric simulations were performed by varying the grid spacing (between 1.0 and 3.0 km) of the high-resolution meteorological model and the set of initial/boundary conditions driving the NWP chain. The aim was to investigate the impact of these parameters not only from a meteorological perspective, but also in terms of discharge predictions for the two flood events. The operational flood forecasting system was thus used as a tool to validate in a more pragmatic sense the quantitative precipitation forecast obtained from different configurations of the NWP system. The results showed an improvement in flood prediction when a high-resolution grid was employed for atmospheric simulations. In turn, a better description of the evolution of the precipitating convective systems was beneficial for the hydrological prediction. Although the simulations underestimated the severity of both floods, the higher-resolution model chain would have provided useful information to the decision-makers in charge of protecting citizens.

scholarly journals The Meteorological Global Model GLOBO at the ISAC-CNR of Italy Assessment of 1.5 Yr of Experimental Use for Medium-Range Weather Forecasts

2011 ◽  
Vol 26 (6) ◽  
pp. 1045-1055 ◽  
Author(s):  
Piero Malguzzi ◽  
Andrea Buzzi ◽  
Oxana Drofa
Keyword(s):  
General Circulation ◽  
Initial Conditions ◽  
Circulation Model ◽  
Daily Basis ◽  
Horizontal Resolution ◽  
Limited Area ◽  
National Council ◽  
Meteorological Model ◽  
Medium Range ◽  
Mean Square Errors

Abstract Since August 2009, the GLOBO atmospheric general circulation model has been running experimentally at the Institute of Atmospheric Sciences and Climate (ISAC) of the National Council of Research of Italy. GLOBO is derived from the Bologna Limited Area Model (BOLAM), a gridpoint limited-area meteorological model that was developed at the same institute and that has been extended to the entire earth atmosphere. The main dynamical features and physical parameterizations of GLOBO are presented. Starting from initial conditions obtained from the analysis of the NCEP Global Forecast System (GFS) model valid at 0000 UTC, 6-day forecasts with average horizontal resolution of 32 km were performed on a daily basis and in real time. The assessment of the forecast skill during the 1.5-yr period included the calculation of the monthly averaged root-mean-square errors (model prediction versus gridded analyses) of geopotential height at 500 hPa and mean sea level pressure for the northern and southern extratropics, performed accordingly to WMO Commission for Basic Systems (CBS) standards. The verification results are compared with models from other global data processing and forecasting system centers, as are available in the literature. The GLOBO skill for medium-range forecasts turns out to be comparable to that of the above models. The lack of analyses based on model forecasts and data assimilation is likely to penalize the scores for shorter-term forecasts.

The ERA5 Global Reanalysis: achieving a detailed record of the climate and weather for the past 70 years.

2020 ◽  
Author(s):  
Hans Hersbach ◽  
Bill Bell ◽  
Paul Berrisford ◽  
Per Dahlgren ◽  
András Horányi ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Land Surface ◽  
Weather Prediction ◽  
Ocean Waves ◽  
Numerical Weather Prediction Model ◽  
Horizontal Resolution ◽  
Special Focus ◽  
Background Error ◽  
Data Assimilation System ◽  
Assimilation System

<p>Reanalysis is a key contribution to the Copernicus Climate Change Service (C3S) that is implemented at the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Commission. The most recent ECMWF reanalysis, ERA5, provides hourly estimates of the global atmosphere, land surface and ocean waves at a horizontal resolution of 31km. Daily updates are provided with a latency of 5 days, while an extension back to 1950 is to be made available in the 2nd quarter of 2020.<br>ERA5 uses a 2016 version of the ECMWF numerical weather prediction model and data assimilation system (Integrated Forecasting System Cy41r2) to assimilate both in situ and satellite observations (95 billion for the period 1979 - 2019), many of which stem from reprocessed data records. The assimilation method includes a variational method for estimating observation biases that respects the heterogeneity within the observing system. Information on random uncertainties in the state estimates is provided by a 10-member ensemble of data assimilations at half the horizontal resolution (63km).<br>This presentation provides a concise overview of the ERA5 data assimilation system. A basic evaluation of characteristics and performance is presented, which includes an inter-comparison with other reanalysis products, such as its predecessor ERA-Interim and several major reanalyses produced elsewhere. Attention is given to the importance of the specification of the background error covariance matrix that determines the weight given to the model's first guess in the assimilation. In addition, a special focus will be on the back extension from 1950 to 1978, where the absence of satellite data prior to the 1970s puts a more demanding constraint on the data assimilation system.</p>

scholarly journals A sensitivity study using two different convection schemes over south america

2008 ◽  
Vol 23 (2) ◽  
pp. 170-189 ◽  
Author(s):  
Luciano Ponzi Pezzi ◽  
Iracema F. A. Cavalcanti ◽  
Antônio M. Mendonça
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
General Circulation ◽  
Initial Conditions ◽  
Circulation Model ◽  
Sensitivity Study ◽  
Reanalysis Data ◽  
Southeastern Brazil ◽  
Convection Scheme ◽  
Convection Schemes

The sensitivity of cumulus convection parameterizations is investigated using the CPTEC/COLA Atmospheric General Circulation Model (AGCM) with T62L28 resolution. This model has been used at CPTEC/INPE since 1995 with the Kuo convective scheme for weather and seasonal climate forecasts. In this study, two sets of integrations are performed using climatological Sea Surface Temperature (SST) of the Southern Hemisphere summer season (December, January and February) as bottom boundary conditions. Five integrations with different initial conditions are applied for each ensemble. The study was divided in two groups, one using the adjusted Relaxed Arakawa-Schubert convection scheme considering modifications in the convection physics (ARAS) and the other one using the Kuo convection scheme (KUO). The atmospheric circulation and precipitation model results are compared with NCEP/NCAR reanalysis data and CMAP precipitation data. The results are analyzed mainly over South America and also for the Southern Hemisphere to verify the model response compared to observed data when different convection scheme is applied. The adjusted scheme for RAS suggested in this study, reduced errors in several areas of South America, when comparing with the previous version. Over most of South America areas KUO gives smaller errors than ARAS. Over tropical Pacific Ocean, Southeastern Brazil and south of northeast Brazil, ARAS scheme shows better results.

scholarly journals Evaluation of Wave Forecasts Consistent with Tropical Cyclone Warning Center Wind Forecasts

2013 ◽  
Vol 28 (1) ◽  
pp. 287-294 ◽  
Author(s):  
Charles R. Sampson ◽  
Paul A. Wittmann ◽  
Efren A. Serra ◽  
Hendrik L. Tolman ◽  
Jessica Schauer ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Wind Field ◽  
Weather Prediction ◽  
Surface Wind ◽  
Track Forecast ◽  
Surface Winds ◽  
Wave Fields ◽  
Wavewatch Iii ◽  
Surface Wind Field

Abstract An algorithm to generate wave fields consistent with forecasts from the official U.S. tropical cyclone forecast centers has been made available in near–real time to forecasters since summer 2007. The algorithm removes the tropical cyclone from numerical weather prediction model surface wind field forecasts, replaces the removed winds with interpolated values from surrounding grid points, and then adds a surface wind field generated from the official forecast into the background. The modified wind fields are then used as input into the WAVEWATCH III model to provide seas consistent with the official tropical cyclone forecasts. Although this product is appealing to forecasters because of its consistency and its superior tropical cyclone track forecast, there has been only anecdotal evaluation of resulting wave fields to date. This study evaluates this new algorithm for two years’ worth of Atlantic tropical cyclones and compares results with those of WAVEWATCH III run with U.S. Navy Operational Global Atmospheric Prediction System (NOGAPS) surface winds alone. Results show that the new algorithm has generally improved forecasts of maximum significant wave heights and 12-ft seas’ radii in proximity to tropical cyclones when compared with forecasts produced using only the NOGAPS surface winds.

scholarly journals Verification of Forecast Weather Surface Variables over Vietnam Using the National Numerical Weather Prediction System

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Tien Du Duc ◽  
Lars Robert Hole ◽  
Duc Tran Anh ◽  
Cuong Hoang Duc ◽  
Thuy Nguyen Ba
Keyword(s):  
Numerical Weather Prediction ◽  
Weather Prediction ◽  
Model Performance ◽  
Wrf Model ◽  
Horizontal Resolution ◽  
Prediction System ◽  
Regional Models ◽  
Global Spectral Model ◽  
Numerical Weather ◽  
The Us

The national numerical weather prediction system of Vietnam is presented and evaluated. The system is based on three main models, namely, the Japanese Global Spectral Model, the US Global Forecast System, and the US Weather Research and Forecasting (WRF) model. The global forecast products have been received at 0.25- and 0.5-degree horizontal resolution, respectively, and the WRF model has been run locally with 16 km horizontal resolution at the National Center for Hydro-Meteorological Forecasting using lateral conditions from GSM and GFS. The model performance is evaluated by comparing model output against observations of precipitation, wind speed, and temperature at 168 weather stations, with daily data from 2010 to 2014. In general, the global models provide more accurate forecasts than the regional models, probably due to the low horizontal resolution in the regional model. Also, the model performance is poorer for stations with altitudes greater than 500 meters above sea level (masl). For tropical cyclone performance validations, the maximum wind surface forecast from global and regional models is also verified against the best track of Joint Typhoon Warning Center. Finally, the model forecast skill during a recent extreme rain event in northeast Vietnam is evaluated.

scholarly journals Modelling tree ring cellulose <i>δ</i><sup>18</sup>O variations in two temperature-sensitive tree species from North and South America

2017 ◽  
Vol 13 (11) ◽  
pp. 1515-1526 ◽  
Author(s):  
Aliénor Lavergne ◽  
Fabio Gennaretti ◽  
Camille Risi ◽  
Valérie Daux ◽  
Etienne Boucher ◽  
...  
Keyword(s):  
South America ◽  
Isotopic Fractionation ◽  
Circulation Model ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Nothofagus Pumilio ◽  
Climate Signal ◽  
North And South America ◽  
North And South ◽  
Two Temperature

Abstract. Oxygen isotopes in tree rings (δ18OTR) are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability in δ18OTR of two temperature-sensitive species of relevant palaeoclimatological interest (Picea mariana and Nothofagus pumilio) and growing at cold high latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N) and western Argentina (41.10° S), we specifically aim at (1) evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2) identifying the physical processes controlling δ18OTR by mechanistic modelling and (3) defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP) may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations) and simulated (by global circulation model) δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability in δ18OTR series is primarily linked to the effect of temperature on isotopic enrichment of the leaf water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil–vegetation–atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.

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