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Previsões climáticas sazonais sobre o Brasil: avaliação do RegCM3 aninhado no modelo global CPTEC/COLA; Seasonal climatic forecast over Brazil: evaluation of the RegCM3 model nested to the CPTEC/COLA global model

MACHADO, Rubinei Dorneles; ROCHA, Rosmeri Porfírio da
Fonte: Sociedade Brasileira de Meteorologia Publicador: Sociedade Brasileira de Meteorologia
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
76.03%
Este trabalho avalia o desempenho de previsões sazonais do modelo climático regional RegCM3, aninhado ao modelo global CPTEC/COLA. As previsões com o RegCM3 utilizaram 60 km de resolução horizontal num domínio que inclui grande parte da América do Sul. As previsões do RegCM3 e CPTEC/COLA foram avaliadas utilizando as análises de chuva e temperatura do ar do Climate Prediction Center (CPC) e National Centers for Enviromental Prediction (NCEP), respectivamente. Entre maio de 2005 e julho de 2007, 27 previsões sazonais de chuva e temperatura do ar (exceto a temperatura do CPTEC/COLA, que possui 26 previsões) foram avaliadas em três regiões do Brasil: Nordeste (NDE), Sudeste (SDE) e Sul (SUL). As previsões do RegCM3 também foram comparadas com as climatologias das análises. De acordo com os índices estatísticos (bias, coeficiente de correlação, raiz quadrada do erro médio quadrático e coeficiente de eficiência), nas três regiões (NDE, SDE e SUL) a chuva sazonal prevista pelo RegCM3 é mais próxima da observada do que a prevista pelo CPTEC/COLA. Além disto, o RegCM3 também é melhor previsor da chuva sazonal do que da média das observações nas três regiões. Para temperatura, as previsões do RegCM3 são superiores às do CPTEC/COLA nas áreas NDE e SUL...

South Atlantic Ocean cyclogenesis climatology simulated by regional climate model (RegCM3)

REBOITA, Michelle Simoes; ROCHA, Rosmeri Porfirio da; AMBRIZZI, Tercio; SUGAHARA, Shigetoshi
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
75.92%
A detailed climatology of the cyclogenesis over the Southern Atlantic Ocean (SAO) from 1990 to 1999 and how it is simulated by the RegCM3 (Regional Climate Model) is presented here. The simulation used as initial and boundary conditions the National Centers for Environmental Prediction-Department of Energy (NCEP/DOE) reanalysis. The cyclones were identified with an automatic scheme that searches for cyclonic relative vorticity (zeta(10)) obtained from a 10-m height wind field. All the systems with zeta(10) a parts per thousand currency sign -1.5 x 10(-5) s(-1) and lifetime equal or larger than 24 h were considered in the climatology. Over SAO, in 10 years were detected 2,760 and 2,787 cyclogeneses in the simulation and NCEP, respectively, with an annual mean of 276.0 +/- A 11.2 and 278.7 +/- A 11.1. This result suggests that the RegCM3 has a good skill to simulate the cyclogenesis climatology. However, the larger model underestimations (-9.8%) are found for the initially stronger systems (zeta(10) a parts per thousand currency sign -2.5 x 10(-5) s(-1)). It was noted that over the SAO the annual cycle of the cyclogenesis depends of its initial intensity. Considering the systems initiate with zeta(10) a parts per thousand currency sign -1.5 x 10(-5) s(-1)...

Future change of climate in South America in the late twenty-first century: intercomparison of scenarios from three regional climate models

MARENGO, Jose A.; AMBRIZZI, Tercio; ROCHA, Rosmeri P. da; ALVES, Lincoln M.; CUADRA, Santiago V.; VALVERDE, Maria C.; TORRES, Roger R.; SANTOS, Daniel C.; FERRAZ, Simone E. T.
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.13%
Regional climate change projections for the last half of the twenty-first century have been produced for South America, as part of the CREAS (Cenarios REgionalizados de Clima Futuro da America do Sul) regional project. Three regional climate models RCMs (Eta CCS, RegCM3 and HadRM3P) were nested within the HadAM3P global model. The simulations cover a 30-year period representing present climate (1961-1990) and projections for the IPCC A2 high emission scenario for 2071-2100. The focus was on the changes in the mean circulation and surface variables, in particular, surface air temperature and precipitation. There is a consistent pattern of changes in circulation, rainfall and temperatures as depicted by the three models. The HadRM3P shows intensification and a more southward position of the subtropical Pacific high, while a pattern of intensification/weakening during summer/winter is projected by the Eta CCS/RegCM3. There is a tendency for a weakening of the subtropical westerly jet from the Eta CCS and HadRM3P, consistent with other studies. There are indications that regions such of Northeast Brazil and central-eastern and southern Amazonia may experience rainfall deficiency in the future, while the Northwest coast of Peru-Ecuador and northern Argentina may experience rainfall excesses in a warmer future...

An assessment of the latent and sensible heat flux on the simulated regional climate over Southwestern South Atlantic Ocean

REBOITA, Michelle Simoes; ROCHA, Rosmeri Porfirio da; AMBRIZZI, Tercio; CAETANO, Ernesto
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
75.93%
A Regional Climate Model (RegCM3) 10-year (1990-1999) simulation over southwestern South Atlantic Ocean (SAO) is evaluated to assess the mean climatology and the simulation errors of turbulent fluxes over the sea. Moreover, the relationship between these fluxes and the rainfall over some cyclogenetic areas is also analyzed. The RegCM3 results are validated using some reanalyses datasets (ERA40, R2, GPCP and WHOI). The summer and winter spatial patterns of latent and sensible heat fluxes simulated by the RegCM3 are in agreement with the reanalyses (WHOI, R2 and ERA40). They show large latent heat fluxes exchange in the subtropical SAO and at higher latitudes in the warm waters of Brazil Current. In particular, the magnitude of RegCM3 latent heat fluxes is similar to the WHOI, which is probably related to two factors: (a) small specific humidity bias, and (b) the RegCM3 flux algorithm. In contrast, the RegCM3 presents large overestimation of sensible heat flux, though it simulates well their spatial pattern. This simulation error is associated with the RegCM3 underestimation of the 2-m air temperature. In southwestern SAO, in three known cyclogenetic areas, the reanalyses and the RegCM3 show the existence of different physical mechanisms that control the annual cycles of latent/sensible heating and rainfall. It is shown that over the eastern coast of Uruguay (35A degrees-43A degrees S) and the southeastern coast of Argentina (44A degrees-52A degrees S) the sea-air moisture and heat exchange play an important role to control the annual cycle of precipitation. This does not happen on the south/southeastern coast of Brazil.; FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[04/02446]; FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[08/58101-9]; CNPq[476361/2006-0.]; CAPES

Precipitation diurnal cycle and summer climatology assessment over South America: An evaluation of Regional Climate Model version 3 simulations

ROCHA, Rosmeri P. da; MORALES, Carlos A.; CUADRA, Santiago V.; AMBRIZZI, Tercio
Fonte: AMER GEOPHYSICAL UNION Publicador: AMER GEOPHYSICAL UNION
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.02%
Regional Climate Model version 3 (RegCM3) simulations of 17 summers (1988-2004) over part of South America south of 5 degrees S were evaluated to identify model systematic errors. Model results were compared to different rainfall data sets (Climate Research Unit (CRU), Climate Prediction Center (CPC), Global Precipitation Climatology Project (GPCP), and National Centers for Environmental Prediction (NCEP) reanalysis), including the five summers mean (1998-2002) precipitation diurnal cycle observed by the Tropical Rainfall Measuring Mission (TRMM)-Precipitation Radar (PR). In spite of regional differences, the RegCM3 simulates the main observed aspects of summer climatology associated with the precipitation (northwest-southeast band of South Atlantic Convergence Zone (SACZ)) and air temperature (warmer air in the central part of the continent and colder in eastern Brazil and the Andes Mountains). At a regional scale, the main RegCM3 failures are the underestimation of the precipitation in the northern branch of the SACZ and some unrealistic intense precipitation around the Andes Mountains. However, the RegCM3 seasonal precipitation is closer to the fine-scale analyses (CPC, CRU, and TRMM-PR) than is the NCEP reanalysis, which presents an incorrect north-south orientation of SACZ and an overestimation of its intensity. The precipitation diurnal cycle observed by TRMM-PR shows pronounced contrasts between Tropics and Extratropics and land and ocean...

Identification and characterization of drought/wet events homogeneous environments based on regional climate simulations

Fernandes, Diego Simoes; Kruger, Luiz Fernando; Heinemann, Alexandre Bryan; da Rocha, Rosmeri Porfirio
Fonte: INST AGRONOMICO; CAMPINAS Publicador: INST AGRONOMICO; CAMPINAS
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
85.96%
The objective of this study was to identify and characterize homogeneous environments based on the probability of drought/wet occurrence in the central-northern Brazil, considering Rondonia, Mato Grosso, Goias and Tocantins States. The drought index denominated the moisture anomaly Z-index (Z-index) was used. The input climate data for the drought index was generated by the regional climate model RegCM3 for the period from 1975 to 1989. As result of cluster analysis, it was identified 13 homogeneous environments. These environments were characterized based on the probability of drought/wet, relative density of drought/wet occurrence, annual rainfall variability and probability of drought occurrence during the rainy season (October to March). The Mato Grosso State had the highest number of homogeneous environments and the environment 11, located at southwest of this State had the highest probability of drought occurrence, 9%. The environment 10, located at the extreme east of Goias State, showed the lowest median for the total annual rainfall. The climatic event with the highest probability of occurrence in the study area is close to normal or normality moisture.

South Atlantic Ocean cyclogenesis climatology simulated by regional climate model (RegCM3)

Reboita, Michelle Simoes; da Rocha, Rosmeri Porfirio; Ambrizzi, Tercio; Sugahara, Shigetoshi
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 1331-1347
ENG
Relevância na Pesquisa
75.91%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Processo FAPESP: 04/02446-7; Processo FAPESP: 01/13925-5; A detailed climatology of the cyclogenesis over the Southern Atlantic Ocean (SAO) from 1990 to 1999 and how it is simulated by the RegCM3 (Regional Climate Model) is presented here. The simulation used as initial and boundary conditions the National Centers for Environmental Prediction-Department of Energy (NCEP/DOE) reanalysis. The cyclones were identified with an automatic scheme that searches for cyclonic relative vorticity (zeta(10)) obtained from a 10-m height wind field. All the systems with zeta(10) a parts per thousand currency sign -1.5 x 10(-5) s(-1) and lifetime equal or larger than 24 h were considered in the climatology. Over SAO, in 10 years were detected 2,760 and 2,787 cyclogeneses in the simulation and NCEP, respectively, with an annual mean of 276.0 +/- A 11.2 and 278.7 +/- A 11.1. This result suggests that the RegCM3 has a good skill to simulate the cyclogenesis climatology. However, the larger model underestimations (-9.8%) are found for the initially stronger systems (zeta(10) a parts per thousand currency sign -2.5 x 10(-5) s(-1)). It was noted that over the SAO the annual cycle of the cyclogenesis depends of its initial intensity. Considering the systems initiate with zeta(10) a parts per thousand currency sign -1.5 x 10(-5) s(-1)...

Simulating Changes in Regional Air Pollution over the Eastern United States Due to Changes in Global and Regional Climate and Emissions

Hogrefe, C.; Lynn, B.; Civerolo, K.; Ku, J.-Y.; Klein-Rosenthal, Joyce Ellen; Rosenzweig, C.; Goldberg, R.; Gaffin, S.; Knowlton, K.; Kinney, P.L.
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
76.14%
[1] To simulate ozone (O3) air quality in future decades over the eastern United States, a modeling system consisting of the NASA Goddard Institute for Space Studies Atmosphere-Ocean Global Climate Model, the Pennsylvania State University/National Center for Atmospheric Research mesoscale regional climate model (MM5), and the Community Multiscale Air Quality model has been applied. Estimates of future emissions of greenhouse gases and ozone precursors are based on the A2 scenario developed by the Intergovernmental Panel on Climate Change (IPCC), one of the scenarios with the highest growth of CO2 among all IPCC scenarios. Simulation results for five summers in the 2020s, 2050s, and 2080s indicate that summertime average daily maximum 8-hour O3 concentrations increase by 2.7, 4.2, and 5.0 ppb, respectively, as a result of regional climate change alone with respect to five summers in the 1990s. Through additional sensitivity simulations for the five summers in the 2050s the relative impact of changes in regional climate, anthropogenic emissions within the modeling domain, and changed boundary conditions approximating possible changes of global atmospheric composition was investigated. Changed boundary conditions are found to be the largest contributor to changes in predicted summertime average daily maximum 8-hour O3 concentrations (5.0 ppb)...

Coupling of Integrated Biosphere Simulator to Regional Climate Model version 3; Coupling of IBIS to RegCM3

Winter, Jonathan (Jonathan Mark)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 102 p.; 1905792 bytes; 1939926 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
65.97%
Presented in this thesis is a description of the coupling of Integrated Biosphere Simulator (IBIS) to Regional Climate Model version 3 (RegCM3), and an assessment of the coupled model (RegCM3-IBIS). RegCM3 is a 3-dimensional, primitive equation limited area model used throughout the world for seasonal predictability and regional climate studies. IBIS is a dynamic global vegetation model that includes representations of land surface processes, canopy physiology, vegetation phenology, terrestrial biogeochemistry, and vegetation dynamics. A single subroutine was created that allows RegCM3 to use IBIS instead of Biosphere-Atmosphere Transfer Scheme 1 e (BATS 1 e) for surface physics calculations. In addition to coupling the two models, a revised initialization scheme was implemented for RegCM3-IBIS, including an IBIS specific prescription of vegetation and soil types, as well as a new scheme for initializing soil moisture, soil ice, and soil temperature based on simulations using the offline version of IBIS. A series of six 1-year numerical experiments were completed to assess the ability of RegCM3-IBIS to simulate the energy and water budgets, as well as surface temperature.; (cont.) The evaluation of RegCM3-IBIS was primarily based on NCEP reanalysis data...

An??lise quantitativa de eventos extremos de precipita????o da regi??o Leste e Norte de Santa Catarina; Quantitative analysis of rainfall extreme events in east and North regions of Santa Catarina State

SILVA, Gilson Carlos da
Fonte: Universidade Federal de Pelotas; Meteorologia; Programa de P??s-gradua????o em Meteorologia; UFPel; BR Publicador: Universidade Federal de Pelotas; Meteorologia; Programa de P??s-gradua????o em Meteorologia; UFPel; BR
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
66.05%
The time-variation feature of extreme precipitation events (those can result in flooding) on east and north regions of the Santa Catarina State, one of the Brazilian regions most attained by damages owning to heavy rain episodes, is analyzed in this study. For this, it were selected some cities whose history of flooding based on many sources, as the Defesa Civil Estadual was employed to built a threshold to identify the precipitation events that can cause flooding. The observed precipitation data, from 1951 to 2010, from ANA (Ag??ncia Nacional de ??guas) was used to the analysis of daily rainfall occurred until fifteen days before the flooding and for the counting of this type of event. The methodology employed to detect these events was based on mean thresholds following the rainfall observed on the selected cities. The counting of the occurrences generated the time-variation over such period, indicating positive and also some negative, although not significant tendencies on this region, and a significative linear correlation with global scale climate phenomena in some of the cities. It is also observed the seasonal behavior for the present time and for a future climate scenario, ranging from 2070 to 2100, which aim is to give information to a better planning of the cities...

Investigating the mechanisms of diurnal rainfall variability using a regional climate model

Evans, J.; Westra, S.
Fonte: Amer Meteorological Soc Publicador: Amer Meteorological Soc
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
75.99%
This study investigates the ability of a regional climate model (RCM) to simulate the diurnal cycle of precipitation over southeast Australia, to provide a basis for understanding the mechanisms that drive diurnal variability. When compared with 195 observation gauges, the RCM tends to simulate too many occurrences and too little intensity for precipitation events at the 3-hourly time scale. However, the overall precipitation amounts are well simulated and the diurnal variability in occurrences and intensities are generally well reproduced, particularly in spring and summer. In terms of precipitation amounts, the RCM overestimated the diurnal cycle during the warmer months but was reasonably accurate during winter. The timing of the maxima and minima was found to match the observed timings well. The spatial pattern of diurnal variability in the Weather Research and Forecasting model outputs was remarkably similar to the observed record, capturing many features of regional variability. The RCM diurnal cycle was dominated by the convective (subgrid scale) precipitation. In the RCM the diurnal cycle of convective precipitation over land corresponds well to atmospheric instability and thermally triggered convection over large areas, and also to the large-scale moisture convergence at 700 hPa along the east coast...

Climate change projections for CORDEX-Africa with COSMO-CLM Regional Climate Model and differences with the driving Global Climate Models.

DOSIO Alessandro; PANITZ Hans-Juergen
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Articles in periodicals and books Formato: Online
ENG
Relevância na Pesquisa
66.06%
In the framework of the Coordinated Regional Climate Downscaling Experiment (CORDEX), an ensemble of climate change projections for Africa has been created by downscaling the simulations of four Global Climate Models (GCM) by means of the Consortium for Small-scale Modeling (COSMO) Regional Climate Model (COSMOCLM, hereafter, CCLM). Differences between the projected temperature and precipitation simulated by CCLM and the driving GCMs are analyzed and discussed. The projected increase of seasonal temperature is found to be relatively similar between GCMs and RCM, although large differences (more than 1◦C) exist locally. Differences are also found for extreme-event related quantities, such as the spread of the upper end of the maximum temperature probability distribution function and, in turn, the duration of heat waves. Larger uncertainties are found in the future precipitation changes; this is partly a consequence of the inter-model (GCMs) variability over some areas (e.g. Sahel). However, over other regions (e.g. Central Africa) the rainfall trends simulated by CCLM and the GCMs show opposite signs, with CCLM showing a significant reduction in precipitation at the end of the century. This uncertain and sometimes contrasting behaviour is further investigated by analyzing the different models' response to the land-atmosphere interaction and feedback. Given the large uncertainty associated with inter-model variability across GCMs and the reduced spread in the results when a single RCM is used for downscaling...

Evaluation of an ensemble of regional climate model simulations over South America driven by the ERA-Interim reanalysis: model performance and uncertainties

Solman, Silvina A.; Sanchez, E.; Samuelsson, P.; Rocha, Rosmeri Porfirio da; Li, L.; Marengo, J.; Pessacg, N. L.; Remedio, A. R. C.; Chou, S. C.; Berbery, H.; Le Treut, H.; Castro, M. de; Jacob, D.
Fonte: Springer; Heidelberg Publicador: Springer; Heidelberg
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
86.11%
The capability of a set of 7 coordinated regional climate model simulations performed in the framework of the CLARIS-LPB Project in reproducing the mean climate conditions over the South American continente has been evaluated. The model simulations were forced by the ERA-Interim reanalysis dataset for the period 1990–2008 on a grid resolution of 50 km, following the CORDEX protocol. The analysis was focused on evaluating the reliability of simulating mean precipitation and surface air temperature, which are the variables most commonly used for impact studies. Both the common features and the differences among individual models have been evaluated and compared against several observational datasets. In this study the ensemble bias and the degree of agreement among individual models have been quantified. The evaluation was focused on the seasonal means, the area-averaged annual cycles and the frequency distributions of monthly means over target subregions. Results show that the Regional Climate Model ensemble reproduces adequately well these features, with biases mostly within ±2 C and ±20 % for temperature and precipitation, respectively. However, the multi-model ensemble depicts larger biases and larger uncertainty (as defined by the standard deviation of the models) over tropical regions compared with subtropical regions. Though some systematic biases were detected particularly over the La Plata Basin region...

Climate Impacts of Deforestation/Land-Use Changes in Central South America in the PRECIS Regional Climate Model: Mean Precipitation and Temperature Response to Present and Future Deforestation Scenarios

Canziani, Pablo O.; Carbajal Benitez, Gerardo
Fonte: The Scientific World Journal Publicador: The Scientific World Journal
Tipo: Artigo de Revista Científica
Publicado em 03/05/2012 EN
Relevância na Pesquisa
66.03%
Deforestation/land-use changes are major drivers of regional climate change in central South America, impacting upon Amazonia and Gran Chaco ecoregions. Most experimental and modeling studies have focused on the resulting perturbations within Amazonia. Using the Regional Climate Model PRECIS, driven by ERA-40 reanalysis and ECHAM4 Baseline model for the period 1961–2000 (40-year runs), potential effects of deforestation/land-use changes in these and other neighboring ecoregions are evaluated. Current 2002 and estimated 2030 land-use scenarios are used to assess PRECIS's response during 1960–2000. ERA-40 and ECHAM4 Baseline driven runs yield similar results. Precipitation changes for 2002 and 2030 land-use scenarios, while significant within deforested areas, do not result in significant regional changes. For temperature significant changes are found within deforested areas and beyond, with major temperature enhancements during winter and spring. Given the current climate, primary effects of deforestation/land-use changes remain mostly confined to the tropical latitudes of Gran Chaco, and Amazonia.

Impacto de las condiciones de suelo en el clima del sur de América del Sur en diferentes escalas temporales; Impact of the soil conditions over the southern South American climate in different time scales

Pessacg, Natalia Liz
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2012 SPA
Relevância na Pesquisa
66.09%
En esta tesis se evalúa la respuesta del clima regional del sur de Sudamérica a dos forzantes locales asociados a las condiciones de superficie, los cambios de uso/cobertura de suelo y los cambios en las condiciones de la humedad de suelo. Por otro lado, se analiza cómo la respuesta del clima regional a distintos forzantes remotos es modulada por los cambios de uso/cobertura de suelo. En primer lugar, se analiza la capacidad de una serie de modelos climáticos regionales para representar los balances de radiación y los flujos de calor en América del Sur, ya que los cambios en las condiciones de superficie afectan fuertemente estos balances. En particular, se evalúa la capacidad del modelo regional MM5, utilizado como herramienta para el abordaje de esta tesis. En segundo lugar, se estudia la respuesta del clima regional del sur de Sudamérica para diferentes escenarios idealizados de cambios de uso/cobertura de suelo, asociados a los procesos de desertificación, reforestación y remplazo de la cobertura actual por tierras para la agricultura, procesos que se han dado en nuestra región en las últimas décadas y que continúan teniendo una tendencia positiva. Se encontró que los cambios en la cobertura de suelo influyen fuertemente sobre la temperatura y la precipitación mediante cambios en los balances de energía y agua en el sur de Sudamérica. En tercer lugar...

Uso de un modelo climático regional para estimar el clima en Sudamérica subtropical para el futuro lejano. Estimación de incertidumbres del modelo; Use of a regional climate model for estimating the subtropical climate in south America far future uncertinties estimation model

Cabré, María Fernanda
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2011 SPA
Relevância na Pesquisa
76.25%
Se presenta un análisis de una simulación regional de cambio climático en el sur de Sudamérica para el escenario SRES A2. Con este objetivo, se han preparado dos simulaciones con el modelo regional MM5, una correspondiente al clima presente (1970-1989) y la otra correspondiente al clima futuro (2080-2099). El modelo regional ha sido forzado por el modelo atmosférico de circulación HadAM3H (Hadley Centre). Este trabajo se centra en la evaluación de la capacidad del modelo en representar el clima presente y la señal de cambio climático para el escenario de emisión SRES A2. La performance del modelo regional fue evaluada en términos de valores medios estacionales, evolución temporal del ciclo anual y variabilidad interanual. Las variables estudiadas son la precipitación, la temperatura y algunas variables de circulación en capas bajas. En líneas generales, el modelo MM5 es capaz de reproducir adecuadamente las principales características del clima observado en Sudamérica. La distribución espacial de la temperatura está bien reproducido, sin embargo pueden encontrarse algunos errores sistemáticos, tales como una sobreestimación en el centro y norte de Argentina y una subestimación en las regiones montañosas a lo largo de todo el año. La estructura general de la precipitación y su evolución estacional...

Changes in European ecosystem productivity and carbon balance driven by regional climate model output

Rowell, David P.; Smith, Benjamin; Sykes, Martin T.; Hickler, Thomas; Morales, Pablo
Fonte: Blackwell Publicador: Blackwell
Tipo: Artículo de revista
EN
Relevância na Pesquisa
66.05%
Climate change resulting from the enhanced greenhouse effect together with the direct effect of increased atmospheric CO2 concentrations on vegetation growth are expected to produce changes in the cycling of carbon in terrestrial ecosystems. Impacts will vary across Europe, and regional-scale studies are needed to resolve this variability. In this study, we used the LPJ-GUESS ecosystem model driven by a suite of regional climate model (RCM) scenarios from the European Union (EU) project PRUDENCE to estimate climate impacts on carbon cycling across Europe. We identified similarities and discrepancies in simulated climate impacts across scenarios, particularly analyzing the uncertainties arising from the range of climate models and emissions scenarios considered. Our results suggest that net primary production (NPP) and heterotrophic respiration (Rh) will generally increase throughout Europe, but with considerable variation between European subregions. The smallest NPP increases, and in some cases decreases, occurred in the Mediterranean, where many ecosystems switched from sinks to sources of carbon by 2100, mainly as a result of deteriorating water balance. Over the period 1991–2100, modeled climate change impacts on the European carbon balance ranged from a sink of 11.6 GtC to a source of 3.3 Gt C...

The role of land surface schemes in the regional climate model (RegCM) for seasonal scale simulations over Western Himalaya

Tiwari,Pushp Raj; Kar,Sarat Chandra; Mohanty,Uma Charan; Dey,Sagnik; Sinha,Palash; Raju,P. V. S.; Shekhar,M. S.
Fonte: Centro de Ciencias de la Atmósfera, UNAM Publicador: Centro de Ciencias de la Atmósfera, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 EN
Relevância na Pesquisa
96.04%
Climate prediction over the Western Himalaya is a challenging task due to the highly variable altitude and orientation of orographic barriers. Surface characteristics also play a vital role in climate simulations and need appropriate representation in the models. In this study, two land surface parameterization schemes (LSPS), the Biosphere-Atmosphere Transfer Scheme (BATS) and the Common Land Model (CLM, version 3.5) in the regional climate model (RegCM, version 4) have been tested over the Himalayan region for nine distinct winter seasons in respect of seasonal precipitation (three years each for excess, normal and deficit). Reanalysis II data of the National Centers for Environmental Prediction (NCEP)/Department of Energy (DOE) have been used as initial and lateral boundary conditions for the RegCM model. In order to provide land surface boundary conditions in the RegCM model, geophysical parameters (10 min resolution) obtained from the United States Geophysical Survey were used. The performance of two LSPS (CLM and BATS) coupled with the RegCM is evaluated against gridded precipitation and surface temperature data sets from the India Meteorological Department (IMD). It is found that the simulated surface temperature and precipitation are better represented in the CLM scheme than in the BATS when compared with observations. Further...

The life cycle of extreme rainfall events over western Saudi Arabia simulated by a regional climate model: Case study of November 1996

Almazroui,M.
Fonte: Centro de Ciencias de la Atmósfera, UNAM Publicador: Centro de Ciencias de la Atmósfera, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
Relevância na Pesquisa
95.98%
A Regional Climate Model (RCM) is employed to simulate and understand the life cycle of the two systems that produced heavy rainfall spells over western Saudi Arabia in November 1996. The first spell of heavy rain occurred from 13 to 20 November, whereas the second occurred from 25 to 27 November 1996. Their spatial patterns are compared with rain-gauge data and also with the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) and the Global Precipitation Climatology Project (GPCP) gridded observations. A series of 144 experiments are conducted for different domain sizes and resolution as well as different boundary forcings and convective parameterization schemes to investigate the optimum combination for the simulation of the two spells. The RCM simulates well the development, the propagation and the life cycle of the first spell (8-day long) as well as the second spell (3-day long) during November 1996. In particular, the simulation demonstrates how the two systems developed, merged with new cells, reached to maturity, and then decayed, as they moved eastward across the Red Sea, producing rain in the study region. A focus over Jeddah station reveals that the RCM simulated well the peak and amount of rainfall for both spells. However...

Climate downscaling over southern South America for present-day climate (1970-1989) using the MM5 model: Mean, interannual variability and internal variability

CABRÉ,FERNANDA; SOLMAN,SILVINA; NÚÑEZ,MARIO
Fonte: Centro de Ciencias de la Atmósfera, UNAM Publicador: Centro de Ciencias de la Atmósfera, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2014 EN
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This work focuses on evaluating the ability of the MM5 regional model to represent the basic features of present climate over South America. The spatial distribution of seasonal means and the interannual variability, as well as annual cycles for precipitation and near-surface temperature have been evaluated. The internal variability has also been investigated. The analysis has two objectives: one of them is to quantify the dynamic downscaling ability to represent the current climate and the other is to identify critical aspects of the regional climate model in South America in order to interpret the reliability of future projections for the end of the twenty-first century in the A2 scenario of the IPCC Special Report on Emissions Scenarios. In general, the MM5 model is able to reproduce adequately the main general features, seasonal cycle and year-to-year variability of near surface variables over South America. The spatial distribution of temperature is well represented, but some systematic errors were identified, such as an overestimation in central and northern Argentina and an underestimation in the mountainous regions throughout the year. The general structure of precipitation is also well captured by the regional model, although it overestimates the precipitation in the Andean region (specifically in central and southern Chile) in all seasons and underestimates the rainfall over tropical latitudes. The annual cycle of precipitation is adequately represented in the subregions analyzed...