Artykuły w czasopismach: „RegCM4.1”

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Reboita, Michelle Simões, Cássia Gabriele Dias, Lívia Márcia Mosso Dutra, Rosmeri Porfírio da Rocha i Marta Llopart. "Previsão Climática Sazonal para o Brasil Obtida Através de Modelos Climáticos Globais e Regional". Revista Brasileira de Meteorologia 33, nr 2 (czerwiec 2018): 207–24. http://dx.doi.org/10.1590/0102-7786332001.

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Resumo Este estudo avalia a destreza de dois modelos climáticos globais (CPTEC e CFSv2) e de um modelo climático regional (RegCM4) em prever o clima sazonal em diferentes regiões do Brasil. O RegCM4 foi dirigido tanto com as saídas do sistema CFSv2 quanto do modelo do CPTEC. Também foram utilizadas duas versões do RegCM: a 4.3 e a 4.5. O RegCM4.3 foi dirigido por seis membros do CFSv2, enquanto o RegCM4.5 foi dirigido por um membro do modelo global do CPTEC. Todas as previsões iniciaram cerca de dois meses antes do trimestre a ser previsto e ao todo foram realizadas 94 simulações com o modelo regional. De forma geral, o RegCM4 adiciona valor às previsões dos modelos climáticos globais, principalmente, quando é aninhado às saídas do modelo do CPTEC. Quando o RegCM4.5 é dirigido por esse modelo global e é utilizada a parametrização de convecção cumulus de Emanuel há uma boa performance do modelo regional na previsão da precipitação e temperatura do ar em quase todo o Brasil.

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Agacayak, Tugba, Tayfun Kindap, Alper Unal, Luca Pozzoli, Marc Mallet i Fabien Solmon. "A case study for Saharan dust transport over Turkey via RegCM4.1 model". Atmospheric Research 153 (luty 2015): 392–403. http://dx.doi.org/10.1016/j.atmosres.2014.09.012.

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Das, Sushant, Sagnik Dey, S. K. Dash i George Basil. "Examining mineral dust transport over the Indian subcontinent using the regional climate model, RegCM4.1". Atmospheric Research 134 (grudzień 2013): 64–76. http://dx.doi.org/10.1016/j.atmosres.2013.07.019.

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Megrelidze, Lia, Nato Kutaladze, Gizo Gogichaishvili i Marina Shvangiradze. "Impact of Climate Change on Some Agricultural Crops Distribution and Productivity in Georgia". Acta Horticulturae et Regiotecturae 24, s1 (1.05.2021): 20–26. http://dx.doi.org/10.2478/ahr-2021-0005.

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Abstract Under the increase of the concern for food security in the world, mainly caused by water resources shortages, the forecast and determination of crop yield at regional scale has been considered as a strategic topic. This study has been conducted to assess the possible impacts of the climate change on cereal crops productivity and irrigation requirement for two main producing regions of Georgia, according to the current crop pattern, and for the 2050s periods. With this aim, water-driven FAO-AquaCrop model has been used. Furthermore, ongoing and forecasted changes, up to the end of the century, in agro-climatic zones relevant for cereals production have been assessed. The climate change data was generated for RCP4.5 scenario through the global circulation model ECHAM4.1, dynamically downscaled on the region via regional climate model (RegCM4.1). Results show overall increase in cereal crop yields, but also enhancement in water shortages even considering optimum management practices under rainfed conditions. Based on the results obtained, recommendations have been developed for adaptation measures to the climate change for the Georgia Agriculture sector.

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O'Brien, T. A., P. Y. Chuang, L. C. Sloan, I. C. Faloona i D. L. Rossiter. "Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds". Geoscientific Model Development 5, nr 4 (3.08.2012): 989–1008. http://dx.doi.org/10.5194/gmd-5-989-2012.

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Abstract. To model stratocumulus clouds in the regional climate model, RegCM4.1, the University of Washington (UW) turbulence parametrization has been coupled to RegCM. We describe improvements in RegCM's coastal and near-coastal climatology, including improvements in the representation of stratiform clouds. By comparing output from a 27-yr (1982–2009) simulation of the climate of western North America to a wide variety of observational data (station data, satellite data, and aircraft in situ data), we show the following: (1) RegCM-UW is appropriate for use in general regional climate studies, and (2) the UW model distinctly improves the representation of the marine boundary layer in RegCM. These model–data comparisons also show that RegCM-UW has a slight cold bias, a (wet) precipitation bias, a systematic low bias in the vertically-integrated liquid water content near the coast, and a high bias in the fractional cloud coverage. The model represents well the diurnal, monthly, and interannual variability in low clouds. These results show RegCM-UW as a nascent mesoscale stratocumulus model that is appropriate for stratocumulus investigations at scales ranging from hourly to decadal. The source code for RegCM-UW is publicly available, under the GNU license, through the International Centre for Theoretical Physics.

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O'Brien, T. A., P. Y. Chuang, L. C. Sloan, I. C. Faloona i D. L. Rossiter. "Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds". Geoscientific Model Development Discussions 4, nr 4 (9.12.2011): 3437–84. http://dx.doi.org/10.5194/gmdd-4-3437-2011.

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Abstract. To model stratocumulus clouds in the regional climate model, RegCM4.1, the University of Washington (UW) turbulence parametrization has been coupled to RegCM. We describe improvements in RegCM's coastal and near-coastal climatology, including improvements in the representation of stratiform clouds. By comparing output from a 27-yr (1982–2009) simulation of the climate of Western North America to a wide variety of observational data (station data, satellite data, and aircraft in situ data), we show the following: (1) RegCM-UW is appropriate for use in general regional climate studies, and (2) the UW model distinctly improves the representation of the marine boundary layer in RegCM. These model-data comparisons also show that RegCM-UW has slight cold bias, a (wet) precipitation bias, a systematic low bias in the vertically-integrated liquid water content near the coast, and a high bias in the fractional cloud coverage. The model represents well the diurnal, monthly, and interannual variability in low clouds. These results show RegCM-UW as a nascent mesoscale stratocumulus model that is appropriate for stratocumulus investigations at scales ranging from hourly to decadal. The source code for RegCM-UW is publicly available, under the GNU license, through the International Centre for Theoretical Physics.

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Sangelantoni, Ferretti i Redaelli. "Toward a Regional-Scale Seasonal Climate Prediction System over Central Italy based on Dynamical Downscaling". Climate 7, nr 10 (5.10.2019): 120. http://dx.doi.org/10.3390/cli7100120.

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Anticipating seasonal climate anomalies is essential for defining short-term adaptation measures. To be actionable, many stakeholders require seasonal forecasts at the regional scale to be properly coupled to region-specific vulnerabilities. In this study, we present and preliminarily evaluate a regional-scale Seasonal Forecast System (SFS) over Central Italy. This system relies on a double dynamical downscaling performed through the Regional-scale Climate Model (RCM) RegCM4.1. A twelve-member ensemble of the NCEP-CFSv2 provides driving fields for the RegCM. In the first step, the RegCM dynamically downscales NCEP-CFSv2 predictions from a resolution of 100 to 60 km over Europe (RegCM-d1). This first downscaling drives a second downscaling over Central Italy at 12 km (RegCM-d2). To investigate the added value of the downscaled forecasts compared to the driving NCEP-CFSv2, we evaluate the driving CFS, and the two downscaled SFSs over the same (inner) domain. Evaluation involves winter temperatures and precipitations over a climatological period (1982–2003). Evaluation for mean bias, statistical distribution, inter-annual anomaly variability, and hit-rate of anomalous seasons are shown and discussed. Results highlight temperature physical values reproduction benefiting from the downscaling. Downscaled inter-annual variability and probabilistic metrics show improvement mainly at forecast lead-time 1. Downscaled precipitation shows an improved spatial distribution with an undegraded but not improved seasonal forecast quality.

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Sun, Hui, Xiaodong Liu i Zaitao Pan. "Direct radiative effects of dust aerosols emitted from the Tibetan Plateau on the East Asian summer monsoon – a regional climate model simulation". Atmospheric Chemistry and Physics 17, nr 22 (17.11.2017): 13731–45. http://dx.doi.org/10.5194/acp-17-13731-2017.

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Abstract. While dust aerosols emitted from major Asian sources such as Taklimakan and Gobi deserts have been shown to have strong effect on Asian monsoon and climate, the role of dust emitted from Tibetan Plateau (TP) itself, where aerosols can directly interact with the TP heat pump because of their physical proximity both in location and elevation, has not been examined. This study uses the dust-coupled RegCM4.1 regional climate model (RCM) to simulate the spatiotemporal distribution of dust aerosols originating within the TP and their radiative effects on the East Asian summer monsoon (EASM) during both heavy and light dust years. Two 20-year simulations with and without the dust emission from TP showed that direct radiative cooling in the mid-troposphere induced by the TP locally produced dust aerosols resulted in an overall anticyclonic circulation anomaly in the low troposphere centered over the TP region. The northeasterly anomaly in the EASM region reduces its strength considerably. The simulations found a significant negative correlation between the TP column dust load produced by local emissions and the corresponding anomaly in the EASM index (r = −0.46). The locally generated TP dust can cause surface cooling far downstream in Bohai Gulf and the China–North Korea border area through stationary Rossby wave propagation. Although dust from within TP (mainly Qaidam Basin) is a relatively small portion of total Asian aerosols, its impacts on Asian monsoon and climate seems disproportionately large, likely owning to its higher elevation within TP itself.

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De Souza, Alexandre Santos, Cleber Souza Correa i Inácio Malmonge Martin. "Avaliação do modelo regional climático para a previsão de temperatura no centro de lançamento de Alcântara". Latin American Journal of Development 3, nr 5 (17.09.2021): 2908–21. http://dx.doi.org/10.46814/lajdv3n5-019.

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Este estudo avaliou a previsão intrasazonal da temperatura à superfície (2 m de altura) na região do Centro de Lançamento de Alcântara (CLA) utilizando O Regional Climate Model RegCM4.7 em comparação aos dados de reanálises obtidos do modelo de reanalises globalERA5 do European Centre for Medium-Range Weather Forecasts (ECMWF) para os meses de abril de 2019 (estação chuvosa) e outubro de 2019 (estação seca). Foram realizadas 4 (quatro) membros de simulações de temperatura utilizando o RegCM4.7 em horários sinóticos, os quais foram comparadas com os dados observacionais e de reanálises do ERA5. Os resultados indicaram uma boa previsibilidade para a temperatura média nos dois períodos, diferenças inferiores a 1 °C, com um grau de diferença para abril e praticamente coincidindo em outubro. Para as temperaturas máximas médias o RegCM4.7 superestimou em 2 °C para abril e 4 °C para outubro. Para as temperaturas médias mínimas subestimou em 2 °C tanto para abril como para outubro. Essas avaliações indicaram um bom desempenho geral para a previsão de temperaturas médias, contudo, sabendo-se da tendência de superestimar temperaturas máximas médias e subestimar temperaturas mínimas médias, ainda assim, com as devidas correções, poderá ser utilizado com eficácia para a previsão intrasazonal de temperatura à superfície em apoio ao planejamento de operações de lançamento no CLA. This study evaluated the intraseasonal surface temperature (2 m height) forecast in the Alcântara Launch Center (ALC) region using the Regional Climate Model RegCM4.7 against reanalysis data obtained from the European Center for Medium-Range Weather global Forecasts (ECMWF) reanalysis model ERA5 for the months of April 2019 (rainy season) and October 2019 (dry season). Four members of temperature simulations were performed using RegCM4.7 at synoptic times, which were compared with observational and reanalysis data from ERA5. The results indicated a good predictability for the average temperature in the two periods, differences below 1 °C, with one degree of difference for April and practically coinciding in October. For average maximum temperatures RegCM4.7 overestimated by 2 °C for April and 4 °C for October. For average minimum temperatures, it was underestimated by 2 °C for both April and October. These evaluations indicated a good overall performance for predicting average temperatures, however, knowing the tendency to overestimate average maximum temperatures and underestimate average minimum temperatures, even so, with the appropriate corrections, it can be used effectively for forecasting intraseasonal surface temperature analysis in support of ALC launch operations planning.

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Phan Van, Tan, Hiep Van Nguyen, Long Trinh Tuan, Trung Nguyen Quang, Thanh Ngo-Duc, Patrick Laux i Thanh Nguyen Xuan. "Seasonal Prediction of Surface Air Temperature across Vietnam Using the Regional Climate Model Version 4.2 (RegCM4.2)". Advances in Meteorology 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/245104.

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To investigate the ability of dynamical seasonal climate predictions for Vietnam, the RegCM4.2 is employed to perform seasonal prediction of 2 m mean (T2m), maximum (Tx), and minimum (Tn) air temperature for the period from January 2012 to November 2013 by downscaling the NCEP Climate Forecast System (CFS) data. For model bias correction, the model and observed climatology is constructed using the CFS reanalysis and observed temperatures over Vietnam for the period 1980–2010, respectively. The RegCM4.2 forecast is run four times per month from the current month up to the next six months. A model ensemble prediction initialized from the current month is computed from the mean of the four runs within the month. The results showed that, without any bias correction (CTL), the RegCM4.2 forecast has very little or no skill in both tercile and value predictions. With bias correction (BAS), model predictions show improved skill. The experiment in which the results from the BAS experiment are further successively adjusted (SUC) with model bias at one-month lead time of the previous run showed further improvement compared to CTL and BAS. Skill scores of the tercile probability forecasts were found to exceed 0.3 for most of the target months.

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Corrêa, Cleber Souza, i Gerson Luiz Camillo. "Intraseasonal climate forecast of iba tropical cyclone in northeast Brazil using the regional climate model - a case study". Ciência e Natura 42 (13.05.2020): e14. http://dx.doi.org/10.5902/2179460x41593.

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This study aimed to analyze the operationally stored simulations of the RegCM4.7 model using simulations performed by the National Center for Environmental Prediction (NCEP) coupled forecast system model version 2 (CFSv2) in downscaling. The South American domain, however, seeks to observe prevailing weather systems that may affect the Alcântara Rocket Launch Center in Maranhão. One case is analyzed with three different global initializations of the CFSv2 model. On March 25, 2019, the occurrence of Cyclone Iba on the southern coast of Bahia. The RegCM4.7 Regional Model was able to simulate tropical cyclone three months in advance. This performance is very important because the influence of these anomalous systems affect wind intensity and rainfall behavior in the Alcântara region because it would affect the convective processes on the continent in northeastern Brazil.

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Ali, Fariz Syafiq Mohamad, Jing Xiang Chung, Poh Heng Kok, Ku Nor Afiza Asnida Ku Mansor i Mohd Fadzil Mohd Akhir. "Evaluation of CORDEX-SEA Models on Wind Simulation during the Southwest Monsoon in the Southwestern Part of the South China Sea". Atmosphere 13, nr 8 (16.08.2022): 1303. http://dx.doi.org/10.3390/atmos13081303.

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This paper assesses the reliability of regional climate downscaling products from the Coordinated Regional Downscaling Experiment-Southeast Asia (CORDEX-SEA) in reproducing the present-day wind at the East Coast of Peninsular Malaysia (ECPM). A total of five CORDEX-SEA products, namely CNRM-CM5(RegCM4), CSIRO-Mk3-6-0(RegCM4), EC-EARTH(RegCM4), HadGEM2-ES(RegCM4) and MPI-ESM-MR(RegCM4), with a resolution of 25 km, were compared to reference data from the European Centre Medium-Range Weather Forecasts (ECMWF) fifth generation atmospheric reanalysis ERA5 spanning 1980–2005. This study focused on the period of the southwest monsoon, specifically the months of June, July and August (JJA), as wind during this season is known to play an important role in generating upwelling at the ECPM. The results obtained show that only three of the CORDEX-SEA products, CSIRO-Mk3-6-0(RegCM4), HadGEM2-ES(RegCM4) and MPI-ESM-MR(RegCM4), were able to reproduce the wind in terms of wind speed, wind stress curl and wind pattern as effectively as ERA5. An ensemble was made from these three CORDEX-SEA products, and it was found that the ensemble was able to reproduce a value of the Upwelling Index (UI) that was similar to the reference data, albeit with some bias. Hence, only the three stated CORDEX-SEA products and their ensemble are suitable to be used for future climate change studies within the region.

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Alexandri, G., A. K. Georgoulias, P. Zanis, E. Katragkou, A. Tsikerdekis, K. Kourtidis i C. Meleti. "On the ability of RegCM4 regional climate model to simulate surface solar radiation patterns over Europe: an assessment using satellite-based observations". Atmospheric Chemistry and Physics 15, nr 22 (27.11.2015): 13195–216. http://dx.doi.org/10.5194/acp-15-13195-2015.

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Abstract. In this work, we assess the ability of RegCM4 regional climate model to simulate surface solar radiation (SSR) patterns over Europe. A decadal RegCM4 run (2000–2009) was implemented and evaluated against satellite-based observations from the Satellite Application Facility on Climate Monitoring (CM SAF), showing that the model simulates adequately the SSR patterns over the region. The SSR bias between RegCM4 and CM SAF is +1.5 % for MFG (Meteosat First Generation) and +3.3 % for MSG (Meteosat Second Generation) observations. The relative contribution of parameters that determine the transmission of solar radiation within the atmosphere to the deviation appearing between RegCM4 and CM SAF SSR is also examined. Cloud macrophysical and microphysical properties such as cloud fractional cover (CFC), cloud optical thickness (COT) and cloud effective radius (Re) from RegCM4 are evaluated against data from CM SAF. Generally, RegCM4 underestimates CFC by 24.3 % and Re for liquid/ice clouds by 36.1 %/28.3 % and overestimates COT by 4.3 %. The same procedure is repeated for aerosol optical properties such as aerosol optical depth (AOD), asymmetry factor (ASY) and single-scattering albedo (SSA), as well as other parameters, including surface broadband albedo (ALB) and water vapor amount (WV), using data from MACv1 aerosol climatology, from CERES satellite sensors and from ERA-Interim reanalysis. It is shown here that the good agreement between RegCM4 and satellite-based SSR observations can be partially attributed to counteracting effects among the above mentioned parameters. The potential contribution of each parameter to the RegCM4–CM SAF SSR deviations is estimated with the combined use of the aforementioned data and a radiative transfer model (SBDART). CFC, COT and AOD are the major determinants of these deviations on a monthly basis; however, the other parameters also play an important role for specific regions and seasons. Overall, for the European domain, CFC, COT and AOD are the most important factors, since their underestimations and overestimations by RegCM4 cause an annual RegCM4–CM SAF SSR absolute deviation of 8.4, 3.8 and 4.5 %, respectively.

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Phan-Van, Tan, Thanh Nguyen-Xuan, Hiep Van Nguyen, Patrick Laux, Ha Pham-Thanh i Thanh Ngo-Duc. "Evaluation of the NCEP Climate Forecast System and Its Downscaling for Seasonal Rainfall Prediction over Vietnam". Weather and Forecasting 33, nr 3 (25.04.2018): 615–40. http://dx.doi.org/10.1175/waf-d-17-0098.1.

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Abstract This study investigates the ability to apply National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFS) products and their downscaling by using the Regional Climate Model version 4.2 (RegCM4.2) on seasonal rainfall forecasts over Vietnam. First, the CFS hindcasts (CFS_Rfc) from 1982 to 2009 are used to assess the ability of the CFS to predict the overall circulation and precipitation patterns at forecast lead times of up to 6 months. Second, the operational CFS forecasts (CFS_Ope) and its RegCM4.2 downscaling (RegCM_CFS) for the period 2012–14 are used to derive seasonal rainfall forecasts over Vietnam. The CFS_Rfc and CFS_Ope are validated against the ECMWF interim reanalysis, the Global Precipitation Climatology Centre (GPCC) analyzed rainfall, and observations from 150 meteorological stations across Vietnam. The results show that the CFS_Rfc can capture the seasonal variability of the Asian monsoon circulation and rainfall distribution. The higher-resolution RegCM_CFS product is advantageous over the raw CFS in specific climatic subregions during the transitional, dry, and rainy seasons, particularly in the northern part of Vietnam in January and in the country’s central highlands during July.

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A Anwar, Samy. "Constraining the Potential Evapotranspiration of Egypt Using the Regional Climate Model (RegCM4) and Climate Research Unit Dataset (CRU)". Journal of Biomedical Research & Environmental Sciences 4, nr 5 (maj 2023): 942–52. http://dx.doi.org/10.37871/jbres1755.

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Accurate forecast of the Potential Evapotranspiration (PET) at a location (where station observation is not available) is necessary in arid/hyper-arid regions (e.g., Egypt) to monitor daily agricultural activities. The Penman-Monteith equation is the standard physical method to compute the PET, but it requires many variables (mostly are calculated empirically). Instead, the Hargreaves-Samani (HS) method was used because it is recommended by the Food and Agriculture Organization and it requires only two variables: global incident solar radiation and daily mean air temperature. Additionally, regional climate models (e.g., RegCM4) can be an alternative tool to estimate the PET constrained by a long-term gridded PET data (Climate Research Unit; CRU) at any location. To accomplish this task, a 39-year simulation was conducted. The RegCM4 was driven by the ERA-Interim reanalysis with 60 km grid spacing. Preliminary results indicated that the RegCM4 was able to capture the monthly variability of the simulated PET with respect to the CRU; however the model overestimates the PET particularly in the summer months (June, July and August). Over all considered locations, performance of the RegCM4 was notably improved when a linear regression model (LRM; between RegCM4 and CRU) was used (indicated by a low bias between the corrected RegCM4 and CRU). In conclusion, the RegCM4 model can accurately calculate the PET at the location of interest by means of the HS equation and a LRM either in the present climate or under different future scenarios.

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Alexandri, G., A. K. Georgoulias, P. Zanis, E. Katragkou, A. Tsikerdekis, K. Kourtidis i C. Meleti. "On the ability of RegCM4 regional climate model to simulate surface solar radiation patterns over Europe: an assessment using satellite-based observations". Atmospheric Chemistry and Physics Discussions 15, nr 13 (8.07.2015): 18487–535. http://dx.doi.org/10.5194/acpd-15-18487-2015.

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Abstract. In this work, we assess the ability of RegCM4 regional climate model to simulate surface solar radiation (SSR) patterns over Europe. A decadal RegCM4 run (2000–2009) was implemented and evaluated against satellite-based observations from the Satellite Application Facility on Climate Monitoring (CM SAF) showing that the model simulates adequately the SSR patterns over the region. The bias between RegCM4 and CM SAF is +1.54 % for MFG (Meteosat First Generation) and +3.34 % for MSG (Meteosat Second Generation) observations. The relative contribution of parameters that determine the transmission of solar radiation within the atmosphere to the deviation appearing between RegCM4 and CM SAF SSR is also examined. Cloud macrophysical and microphysical properties such as cloud fractional cover (CFC), cloud optical thickness (COT) and cloud effective radius (Re) from RegCM4 are evaluated against data from CM SAF. The same procedure is repeated for aerosol optical properties such as aerosol optical depth (AOD), asymmetry factor (ASY) and single scattering albedo (SSA), as well as other parameters including surface broadband albedo (ALB) and water vapor amount (WV) using data from MACv1 aerosol climatology, from CERES satellite sensors and from ERA-Interim reanalysis. It is shown here that the good agreement between RegCM4 and satellite-based SSR observations can be partially attributed to counteracting effects among the above mentioned parameters. The contribution of each parameter to the RegCM4-CM SAF SSR deviations is estimated with the combined use of the aforementioned data and a radiative transfer model (SBDART). CFC, COT and AOD are the major determinants of these deviations; however, the other parameters also play an important role for specific regions and seasons.

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LLOPART, M. P., M. S. REBOITA, R. P. ROCHA i J. P. MACHADO. "Performance of the Coupling RegCM4.3 and CLM3.5: An Analysis Over Southeastern Brazil". Anuário do Instituto de Geociências - UFRJ 41, nr 3 (4.12.2018): 113–24. http://dx.doi.org/10.11137/2018_3_113_124.

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Yang, Minghao, Ruiting Zuo, Liqiong Wang i Xiong Chen. "Simulation of Land Surface Climate over China with RegCM4.5: Verification and Analysis". Advances in Meteorology 2018 (2018): 1–14. http://dx.doi.org/10.1155/2018/7960908.

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The ability of RegCM4.5 using land surface scheme CLM4.5 to simulate the physical variables related to land surface state was investigated. The NCEP-NCAR reanalysis data for the period 1964–2003 were used to drive RegCM4.5 to simulate the land surface temperature, precipitation, soil moisture, latent heat flux, and surface evaporation. Based on observations and reanalysis data, a few land surface variables were analyzed over China. The results showed that some seasonal features of land surface temperature in summer and winter as well as its magnitude could be simulated well. The simulation of precipitation was sensitive to region and season. The model could, to a certain degree, simulate the seasonal migration of rainband in East China. The overall spatial distribution of the simulated soil moisture was better in winter than in summer. The simulation of latent heat flux was also better in winter. In summer, the latent heat flux bias mainly arose from surface evaporation bias in Northwest China, and it primarily arose from vegetation evapotranspiration bias in South China. In addition, the large latent heat flux bias in South China during summer was probably due to less precipitation generated in the model and poor representation of vegetation cover in this region.

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Rahman, Muhammad Tanjilur, Md Nazmul Ahasan, Md Abdul Mannan, Madan Sigdel, Dibas Shrestha, Archana Shrestha, Deepak Aryal i Khan Md Golam Rabbani. "Simulation of Rainfall over Bangladesh Using Regional Climate Model (RegCM4.7)". Jalawaayu 1, nr 2 (2.12.2021): 1–19. http://dx.doi.org/10.3126/jalawaayu.v1i2.41007.

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Regional climate model is a scientific tool to monitor present climate change and to provide reliable estimation of future climate projection. In this study, the Regional Climate Model version 4.7 (RegCM4.7) developed by International Centre for Theoretical Physics (ICTP) has been adopted to simulate rainfall scenario of Bangladesh. The study examines model performance of rainfall simulation through the period of 1991-2018 with ERA-Interim75 data of 75 km horizontal resolution as lateral boundaries, downscaled at 25km resolution using the mixed convective precipitation scheme; MIT-Emanuel scheme over land and Grell scheme with Fritsch-Chappell closure over ocean. The simulated rainfall has been compared both at spatial and temporal scales (monthly, seasonal and annual) with observed data collected from Bangladesh Meteorological Department (BMD) and Climate Research Unit (CRU). Simulated annual rainfall showed that the model overestimated in most of the years. Overestimation has been observed in the monsoon and underestimation in pre-monsoon and post-monsoon seasons. Spatial distribution of simulated rainfall depicts overestimation in the southeast coastal region and underestimation in the northwest and northeast border regions of Bangladesh. Better estimation of rainfall has been found in the central and eastern parts of the country. The simulated annual rainfall has been validated through the Linear Scaling bias correction method for the years of 2016, 2017, and 2018 considering the rainfall of 1991-2015 as reference. The bias correction with linear scaling method gives fairly satisfactory results and it can be considered in the future projection of rainfall over Bangladesh.

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Güttler, Ivan, Čedo Branković, Lidija Srnec i Mirta Patarčić. "The impact of boundary forcing on RegCM4.2 surface energy budget". Climatic Change 125, nr 1 (15.11.2013): 67–78. http://dx.doi.org/10.1007/s10584-013-0995-x.

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Gu, Huanghe, i Xiaoyan Wang. "Performance of the RegCM4.6 for High-Resolution Climate and Extreme Simulations over Tibetan Plateau". Atmosphere 11, nr 10 (15.10.2020): 1104. http://dx.doi.org/10.3390/atmos11101104.

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This paper presents an evaluation of the Regional Climate Model version 4.6.1 (RegCM4) at a high-resolution simulation at 10 km applied over the Tibetan Plateau. This simulation covers the period from 1980 to 2010 and is nested in a RegCM4 simulation at 30-km resolution, which is driven by the main European Centre for Medium-Range Weather and Forecasting reanalysis (ERA-Interim reanalysis) dataset. A new daily observational dataset is employed as reference data to evaluate the temperature and precipitation simulations for the inner model domain and the five largest river basins that originated in the Tibetan Plateau (TP) (i.e., the source region of Yangtze River, Yellow River, Mekong River, Salween River, and Brahmaputra River). In comparison with the low-resolution model run (R30), the cold biases for the area-averaged temperature were reduced from −2.5 to −0.1° C and the wet biases in summer mean precipitation were reduced from 58% to 25% in the high-resolution model run (R10). The substantial warming trends and slight wetting trends were basically reproduced by both RegCM4 simulations. Annual mean precipitation trends from both simulations show a better agreement with the observations than the ERA-Interim, which underestimates the annual mean precipitation trends in most regions, whereas both the RegCM4 and ERA-Interim consistently underestimate the annual mean temperature trends when compared with the observations. In addition, the overall improvement in the modeling trends for annual mean temperature and precipitation in R10 is limited when compared with R30. The extreme precipitation was also captured reasonably in both RegCM4 simulations, and the better performance is detected in the R10 simulation. The findings above show that RegCM4 with a high-resolution of 10 km is capable of reproducing the major regional climate features over the TP, but a great deal of uncertainties still exist, especially in the subregion of the Brahmaputra River basin. Thus, the 10-km resolution simulation in RegCM4 may still not be fine enough to resolve the topoclimates over the complex Himalayan terrain in the Brahmaputra River basin.

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Coppola, Erika, Paolo Stocchi, Emanuela Pichelli, Jose Abraham Torres Alavez, Russell Glazer, Graziano Giuliani, Fabio Di Sante, Rita Nogherotto i Filippo Giorgi. "Non-Hydrostatic RegCM4 (RegCM4-NH): model description and case studies over multiple domains". Geoscientific Model Development 14, nr 12 (21.12.2021): 7705–23. http://dx.doi.org/10.5194/gmd-14-7705-2021.

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Abstract. We describe the development of a non-hydrostatic version of the regional climate model RegCM4, called RegCM4-NH, for use at convection-permitting resolutions. The non-hydrostatic dynamical core of the Mesoscale Model MM5 is introduced in the RegCM4, with some modifications to increase stability and applicability of the model to long-term climate simulations. Newly available explicit microphysics schemes are also described, and three case studies of intense convection events are carried out in order to illustrate the performance of the model. They are all run at a convection-permitting grid spacing of 3 km over domains in northern California, Texas and the Lake Victoria region, without the use of parameterized cumulus convection. A substantial improvement is found in several aspects of the simulations compared to corresponding coarser-resolution (12 km) runs completed with the hydrostatic version of the model employing parameterized convection. RegCM4-NH is currently being used in different projects for regional climate simulations at convection-permitting resolutions and is intended to be a resource for users of the RegCM modeling system.

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Tsikerdekis, A., P. Zanis, L. A. Steiner, V. Amiridis, E. Marinou, E. Katragkou, Th Karacostas i F. Solmon. "MODELING THE TRANS-ATLANTIC TRANSPORTATION OF SAHARAN DUST". Bulletin of the Geological Society of Greece 50, nr 2 (27.07.2017): 1052. http://dx.doi.org/10.12681/bgsg.11810.

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In the present study we are simulating the trans-Atlantic transport of dust from Sahara to the South-Central America, using the regional climate model RegCM4 and its online dust scheme, for the year 2007. The simulated horizontal and vertical distributions of the mineral dust optical properties were evaluated against the LIVAS CALIPSO satellite dust product. The Trans-Atlantic dust transport is simulated adequately with RegCM4, but there are some spatial discrepancies. Dust optical thickness is overestimated in the eastern Sahara throughout the year by 0.1-0.2, while near the gulf of Guinea is underestimated during winter and spring. Although RegCM4 dust plume is located southern on winter and spring, it doesn't spatially match the dust optical thickness of LIVAS. In summer and autumn the vertical distribution of dust between 3-4km during the Trans-Atlantic transport is simulated by the model adequately up to 30ºW 40ºW longitude. However, during winter-spring RegCM4 misplaces dust loading into higher altitude. Finally, we discuss some possible reasons and mechanisms that might be responsible for the differences between the model and the observations.

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Stocchi, Paolo, Emanuela Pichelli, Jose Abraham Torres Alavez, Erika Coppola, Graziano Giuliani i Filippo Giorgi. "Non-Hydrostatic Regcm4 (Regcm4-NH): Evaluation of Precipitation Statistics at the Convection-Permitting Scale over Different Domains". Atmosphere 13, nr 6 (25.05.2022): 861. http://dx.doi.org/10.3390/atmos13060861.

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Recent studies over different geographical regions of the world have proven that regional climate models at the convection-permitting scale (CPMs) improve the simulation of precipitation in many aspects, such as the diurnal cycle, precipitation frequency, intensity, and extremes at daily—but even more at hourly—time scales. Here, we present an evaluation of climate simulations with the newly developed RegCM4-NH model run at the convection-permitting scale (CP-RegCM4-NH) for a decade-long period, over three domains covering a large European area. The simulations use a horizontal grid spacing of ~3 km and are driven by the ERA-Interim reanalysis through an intermediate driving RegCM4-NH simulation at ~12 km grid spacing with parameterized deep convection. The km-scale simulations are evaluated against a suite of hourly observation datasets with high spatial resolutions and are compared to the coarse-resolution driving simulation in order to assess improvements in precipitation from the seasonal to hourly scale. The results show that CP-RegCM4-NH produces a more realistic representation of precipitation than the coarse-resolution simulation over all domains. The most significant improvements were found for intensity, heavy precipitation, and precipitation frequency, both on daily and hourly time scales in all seasons. In general, CP-RegCM4-NH tends to correctly produce more intense precipitation and to reduce the frequency of events compared to the coarse-resolution one. On the daily scale, improvements in CP simulations are highly region dependent, with the best results over Italy, France, and Germany, and the largest biases over Switzerland, the Carpathians, and Greece, especially during the summer seasons. At the hourly scale, the improvement in CP simulations for precipitation intensity and spatial distribution is clearer than at the daily timescale. In addition, the representation of extreme events is clearly improved by CP-RegCM4-NH, particularly at the hourly time scale, although an overestimation over some subregions can be found. Although biases between the model simulations at the km-scale and observations still exist, this first application of CP-RegCM4-NH at high spatial resolution indicates a clear benefit of convection-permitting simulations and encourages further assessments of the added value of km-scale model configurations for regional climate change projections.

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Santos, Sérgio Rodrigo, Everaldo Barreiro Souza, Thamiris Luiza De Oliveira Brandão Campos, Clovis Angeli Sansigolo i Ana Paula Paes Santos. "Aspectos Regionais do Padrão Sazonal da Precipitação sobre a Amazônia utilizando o Modelo RegCM4 (Regional Aspects of Standard of Seasonal Rainfall on Amazon Using the Model RegCM4)". Revista Brasileira de Geografia Física 9, nr 3 (5.06.2016): 917. http://dx.doi.org/10.26848/rbgf.v9.3.p917-926.

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O objetivo deste trabalho é avaliar a eficiência do modelo RegCM4 em reproduzir as precipitações sazonais sobre a Amazônia no clima atual (1979-2014), com referência ao conjunto de dados do GPCP. De maneira geral, os resultados mostraram que o RegCM4 reproduziu de maneira satisfatória os padrões sazonais de precipitação na Região. Contudo, as análises quantitativas demonstraram que o RegCM4 apresenta erros sistemáticos de subestimativa (viés negativo) no verão e outono, e superestimava (viés positivo) no inverno e primavera. Além disso, foi investigado o desempenho do modelo em reproduzir os padrões anômalos sazonais de precipitação. Os resultados demonstraram uma boa concordância entre as anomalias de chuva observadas e simuladas no período estudado.

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Ogwang, Bob Alex, Haishan Chen, Xing Li i Chujie Gao. "Evaluation of the capability of RegCM4.0 in simulating East African climate". Theoretical and Applied Climatology 124, nr 1-2 (7.03.2015): 303–13. http://dx.doi.org/10.1007/s00704-015-1420-3.

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Reboita, Michelle Simões, Thales Alves Theodoro, Glauber Willian de Souza Ferreira i Christie Andre de Souza. "Ciclo de Vida do Sistema de Monção da América do Sul: Clima Presente e Futuro". Revista Brasileira de Geografia Física 15, nr 1 (23.03.2022): 343. http://dx.doi.org/10.26848/rbgf.v15.1.p343-358.

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O Painel Intergovernamental sobre Mudanças Climáticas (IPCC), responsável por compilar o conhecimento produzido sobre as mudanças do clima da Terra, conta com o apoio de grupos internacionais de pesquisa que executam projeções climáticas com modelos climáticos globais (MCGs) e regionais (MCRs). Com relação aos MCRs, o Coordinated Regional Climate Downscaling Experiment (CORDEX) é o responsável pela criação de protocolos para padronização das simulações, execução dessas e disponibilização em banco de dados de acesso público. Para gerar informações para o sexto relatório de avaliação (AR6) do IPCC, que foi publicado recentemente (09 de agosto de 2021), o Regional Climate Model (RegCM4) do Centro de Física Teórica (ICTP) da Itália foi um dos modelos executados pelo CORDEX. Essas projeções são a base para o desenvolvimento do presente estudo cujo objetivo é identificar o início, fim e duração da estação chuvosa na América do Sul no clima presente (1995-2014) e futuro (2080-2099) considerando o cenário RCP8.5. Para tanto, são considerados dois ensembles: um com as projeções dos modelos globais que dirigiram o RegCM4 e outro com as projeções desse modelo regional. Entre os resultados estão a projeção de condições mais secas na região da Zona de Convergência do Atlântico Sul durante a primavera e sobre a Amazônia no verão. No sul da Amazônia, o ciclo de vida da monção no ensemble dos MCGs (RegCM4) é projetado iniciar entre as pêntadas 59-60 (58-61) e decair nas pêntadas 22-26 (23-27). A mesma análise indica para a região Sudeste a monção iniciar entre as pêntadas 56-60 (57-65) a decair entre as pêntadas 15-20 (15-20) pelo ensemble dos MCGs (RegCM4). Com esse estudo foi possível mostrar que tanto os MCGS quanto o RegCM4 projetam alterações importantes no ciclo de vida da monção da América do Sul.Palavras-chaves: IPCC, mudanças climáticas, cenários, América do Sul, precipitação, estação chuvosa Life cycle of the South American monsoon system: present and future climate A B S T R A C TThe Intergovernmental Panel on Climate Change (IPCC), responsible for compiling the knowledge produced about observed and projected changes in the Earth's climate, has the support of international research groups that carry out climate projections with global climate models (GCMs) and regional climate models (RCMs). With regard to RCMs, the Coordinated Regional Climate Downscaling Experiment (CORDEX) is responsible for creating protocols for standardizing simulations, executing them and making them available in a publicly accessible database. To generate information for the IPCC's sixth assessment report (AR6), which was published recently (August 9, 2021), the Regional Climate Model (RegCM4) of the International Centre for Theoretical Physics (ICTP) of Italy was one of the models executed by CORDEX. These projections are the basis for the development of this study whose objective is to identify the onset, end and duration of the rainy season in South America in the present (1995-2014) and future (2080-2099) climate considering the RCP8.5 scenario. For that, two ensembles are considered: one with the projections of the global models that drove RegCM4 and the other with the projections of this regional model. Among the results are the projection of drier conditions in the South Atlantic Convergence Zone region during spring and over the Amazon in summer. In southern Amazon, the monsoon lifecycle in the GCMs (RegCM4) ensemble is projected to begin between pentads 59-60 (58-61) and decay between pentads 22-26 (23-27). The same analysis indicates for the Southeast Brazil a monsoon onset between pentads 56-60 (57-65) and a demise between pentads 15-20 (15-20) by the ensemble of GCMs (RegCM4). These results indicate a shorter lifecycle of the wet phase of the monsoon in the future climate compared to the historical one. This study showed that both GCMs and RegCM4 project important changes in the lifecycle of the South American monsoon.Keywords: IPCC, climate change, scenarios, South America, precipitation, rainy season

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Almazroui, Mansour. "Temperature Changes over the CORDEX-MENA Domain in the 21st Century Using CMIP5 Data Downscaled with RegCM4: A Focus on the Arabian Peninsula". Advances in Meteorology 2019 (20.05.2019): 1–18. http://dx.doi.org/10.1155/2019/5395676.

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This paper examined the temperature changes from the COordinated Regional climate Downscaling Experiment (CORDEX) over the Middle East and North Africa (MENA) domain called CORDEX-MENA. The focus is on the Arabian Peninsula in the 21st century, using data from three Coupled Model Intercomparison Project Phase 5 (CMIP5) models downscaled by RegCM4, a regional climate model. The analysis includes surface observations along with RegCM4 simulations and changes in threshold based on extreme temperature at the end of the 21st century relative to the base period (1971–2000). Irrespective of the driving CMIP5 models, the RegCM4 simulations show enhanced future temperature changes for RCP8.5 as compared to RCP4.5. The Arabian Peninsula will warm at a faster rate (0.83°C per decade) as compared to the entire domain (0.79°C per decade) for RCP8.5 during the period 2071–2100. Moreover, the number of hot days (Tmax ≥ 50°C) (cold nights: Tmin ≤ 5°C) will increase (decrease) faster in the Arabian Peninsula as compared to the entire domain. This increase (decrease) of hot days (cold nights) will be more prominent in the far future (2071–2100) as compared to the near future (2021–2050) period. Moreover, the future changes in temperature over the main cities in Saudi Arabia are also projected. The RegCM4-based temperature simulation data from two suitable CMIP5 models are recommended as a useful database for further climate-change-related studies.

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Nguyen-Xuan, Thanh, Sze Lok Lam, Filippo Giorgi, Erika Coppola, Graziano Giuliani, Xuejie Gao i Eun-Soon Im. "Evaluation of the performance of the non-hydrostatic RegCM4 (RegCM4-NH) over Southeastern China". Climate Dynamics 58, nr 5-6 (5.10.2021): 1419–37. http://dx.doi.org/10.1007/s00382-021-05969-5.

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Nguyen-Xuan, Thanh, Sze Lok Lam, Filippo Giorgi, Erika Coppola, Graziano Giuliani, Xuejie Gao i Eun-Soon Im. "Evaluation of the performance of the non-hydrostatic RegCM4 (RegCM4-NH) over Southeastern China". Climate Dynamics 58, nr 5-6 (5.10.2021): 1419–37. http://dx.doi.org/10.1007/s00382-021-05969-5.

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Maharana, P., Dhirendra Kumar i A. P. Dimri. "Assessment of coupled regional climate model (RegCM4.6–CLM4.5) for Indian summer monsoon". Climate Dynamics 53, nr 11 (24.08.2019): 6543–58. http://dx.doi.org/10.1007/s00382-019-04947-2.

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Xiang-ling, Tang, Lv Xin i Zhang Yanwei. "Estimation of future extreme precipitation changes in Xinjiang based on RegCM4.4 simulations". Natural Hazards 102, nr 1 (22.04.2020): 201–18. http://dx.doi.org/10.1007/s11069-020-03920-1.

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Pieczka, Ildikó, Rita Pongrácz, Karolina Szabóné André, Fanni Dóra Kelemen i Judit Bartholy. "Sensitivity analysis of different parameterization schemes using RegCM4.3 for the Carpathian region". Theoretical and Applied Climatology 130, nr 3-4 (4.10.2016): 1175–88. http://dx.doi.org/10.1007/s00704-016-1941-4.

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Güttler, Ivan, Čedo Branković, Travis A. O’Brien, Erika Coppola, Branko Grisogono i Filippo Giorgi. "Sensitivity of the regional climate model RegCM4.2 to planetary boundary layer parameterisation". Climate Dynamics 43, nr 7-8 (27.11.2013): 1753–72. http://dx.doi.org/10.1007/s00382-013-2003-6.

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Suh, Myoung-Seok, Tae-Jun Kim i Eun-Chul Chang. "Future Projections of Changes in Extreme Temperature over South Korea for the Mid and Late 21st Century using RegCM4.0 Simulations over CORDEX II East Asia". Journal of Climate Research 14, nr 2 (30.06.2019): 69–94. http://dx.doi.org/10.14383/cri.2019.14.2.69.

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Pareja-Quispe, David, Sergio Henrique Franchito i Julio Pablo Reyes Fernandez. "Assessment of the RegCM4 Performance in Simulating the Surface Radiation Budget and Hydrologic Balance Variables in South America". Earth Systems and Environment 5, nr 3 (14.08.2021): 499–518. http://dx.doi.org/10.1007/s41748-021-00249-y.

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AbstractThe ability of the Regional Climate Model v4 (RegCM4) to simulate the surface radiation budget and hydrological balance variables over South America have been evaluated. For this purpose, a 34-year long simulation was carried out with the regional climate model RegCM4 over South America on the CORDEX domain. The model is forcing by ERA-Interim reanalysis. The results show that RegCM4 simulates the main patterns of the variables associated with the surface radiation budget and hydrological balance in the four seasons of the year compared to the observations (CLARA2 and CRU/PERSIANN). However, the cloudiness and surface radiation budget variables: Cloud Fraction Cover (CFC), net shortwave (SW) and longwave (LW) radiation at surface are overestimated, mainly over the oceans. This is associated with the errors in the CFC due to the deficiency of the model in representing the low-level clouds. Some differences are also noted in the hydrological balance. The intensity and temporal evolution of precipitation, especially in the central and southern Amazon, may be associated with the selected domain, which fails to adequately represent the influence of the adjoining oceans. In northern and northeast parts, the differences are associated with deficiencies of RegCM4 in representing precipitation rates. Although the deficiencies, taking into account that the model is capable to reproduce the general pattern of some important variables of the surface radiation budget and hydrological cycle, it may be a useful tool for climate studies.

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Diba, Ibrahima, Moctar Camara i Arona Diedhiou. "Investigating West African Monsoon Features in Warm Years Using the Regional Climate Model RegCM4". Atmosphere 10, nr 1 (10.01.2019): 23. http://dx.doi.org/10.3390/atmos10010023.

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This study investigates the changes in West African monsoon features during warm years using the Regional Climate Model version 4.5 (RegCM4.5). The analysis uses 30 years of datasets of rainfall, surface temperature and wind parameters (from 1980 to 2009). We performed a simulation at a spatial resolution of 50 km with the RegCM4.5 model driven by ERA-Interim reanalysis. The rainfall amount is weaker over the Sahel (western and central) and the Guinea region for the warmest years compared to the coldest ones. The analysis of heat fluxes show that the sensible (latent) heat flux is stronger (weaker) during the warmest (coldest) years. When considering the rainfall events, there is a decrease of the number of rainy days over the Guinea Coast (in the South of Cote d’Ivoire, of Ghana and of Benin) and the western and eastern Sahel during warm years. The maximum length of consecutive wet days decreases over the western and eastern Sahel, while the consecutive dry days increase mainly over the Sahel band during the warm years. The percentage of very warm days and warm nights increase mainly over the Sahel domain and the Guinea region. The model also simulates an increase of the warm spell duration index in the whole Sahel domain and over the Guinea Coast in warm years. The analysis of the wind dynamic exhibits during warm years a weakening of the monsoon flow in the lower levels, a strengthening in the magnitude of the African Easterly Jet (AEJ) in the mid-troposphere and a slight increase of the Tropical Easterly Jet (TEJ) in the upper levels of the atmosphere during warm years.

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Zhang, Wanxin, Haishan Chen, Liming Zhou, Botao Zhou, Jie Zhang i Jiangfeng Wei. "Effects of Nonuniform Land Surface Warming on Summer Anomalous Extratropical Cyclone Activity and the East Asian Summer Monsoon: Numerical Experiments with a Regional Climate Model". Journal of Climate 33, nr 24 (15.12.2020): 10469–88. http://dx.doi.org/10.1175/jcli-d-20-0088.1.

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AbstractPrevious studies detected significant negative correlations between the nonuniform land surface warming and the decadal weakened activities of the summer extratropical cyclones (ECs) over East Asia and the East Asian summer monsoon (EASM) after the early 1990s. Here such relationships are further examined and the possible mechanisms are explored via numerical sensitivity experiments with a regional climate model (RegCM4.5). The positive/negative sensible heat flux (SH) anomalies were added as a forcing to a key region near 50°N of East Asia in RegCM4.5 to simulate the observed ground surface temperature (GST) anomalies. The model results suggest that the nonuniform land surface warming over the Lake Baikal area (50°–60°N, 90°–120°E) can indeed cause the weakening of the extratropical cyclogenesis and affect the decadal weakening of the EASM. Warm (cold) GST forcing over the key GST region can lead to decreasing (increasing) atmospheric baroclinicity and related energy conversion of the EC activity over the key EC region (40°–50°N, 90°–120°E), resulting in an evidently weakening (enhancing) of the ECs over East Asia. Meanwhile, precipitation shows a dipole pattern with significantly suppressed (enhanced) precipitation in northern and northeastern China, and slightly enhanced (suppressed) rainfall south of 40°N of East Asia, mainly over the East China Sea. Lake Baikal and its adjacent areas are occupied by a strong anticyclonic (cyclonic) circulation while the southeast coastal areas of China have a relatively weak cyclonic (anticyclonic) circulation accompanied with an anomalous northeasterly (southwesterly) wind to the southeast of the anticyclonic circulation, which is opposite to (coincident with) the atmospheric circulation anomalies that are associated with the second mode of the EASM.

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Song, Tangnyu, Guohe Huang, Guoqing Wang, Yongping Li, Xiuquan Wang, Chen Lu i Zhenyao Shen. "Bayesian model averaging of the RegCM temperature projections: a Canadian case study". Journal of Water and Climate Change 13, nr 2 (26.10.2021): 771–85. http://dx.doi.org/10.2166/wcc.2021.393.

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Abstract The choices of physical schemes coupled in the Regional Climate Model version 4 (RegCM4), the input general circulation model (GCM) results, and the emission scenarios may cause considerable uncertainties in future temperature projections. Therefore, the ensemble approach, which can be used to reflect these uncertainties, is highly desired. In this study, the probabilistic projections for future temperature are generated at 88 Canadian climate stations based on the developed RegCM4 ensemble and obtained Bayesian model averaging (BMA) weights. The BMA weights indicate that the RegCM4 coupled with the holtslag PBL scheme driven by the HadGEM can provide relatively reliable temperature projections at most climate stations. It is also suggested that the BMA approach is effective in simulating temperature over middle and eastern Canada through taking advantage of each ensemble member. However, the effectiveness of the BMA method is limited when all the models in the ensemble cannot simulate the temperature robustly. The projected results demonstrate that the temperature will increase continuously in the future, while the temperature increase under RCP8.5 will be significantly larger than that under RCP4.5.

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Ávila, Pâmela Lorena Ribeiro, Everaldo Barreiros de Souza i Amanda Nascimento Pinheiro. "Simulação da Precipitação Sazonal com o Regcm4 sobre o Estado do Pará para Anos de El Niño e La Niña (Simulation of Seasonal Precipitation with Regcm4 about the State of Pará for Years of El Niño and La Niña)". Revista Brasileira de Geografia Física 6, nr 5 (18.12.2013): 1316. http://dx.doi.org/10.26848/rbgf.v6i5.233107.

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Este trabalho apresenta uma contribuição aos estudos de modelagem climática com ênfase na variabilidade pluviométrica sazonal do estado do Pará, durante as estações de verão e outono (DJF e MAM). Baseado nos resultados das simulações regionais do RegCM4 para os anos de El Niño (1982/83) e Lã Niña (1988/89) usando domínio em alta resolução espacial (50 Km) e dois diferentes esquemas de convecção (Grell e MIT), foi investigado o desempenho do modelo em simular a distribuição regional de precipitação sazonal no estado do Pará. As análises quantitativas evidenciaram que o RegCM4 apresenta erros sistemáticos, sobretudo aqueles relacionados a uma subestimativa das chuvas nas três grades (G1, G2, G3) para os anos de El Niño e Lã Niña sendo representativo apenas em pequenas áreas na região sudeste do estado no período do verão para o esquema Grell, e mostrou-se mais representativo na grade G2 do para o ano de El Niño no esquema MIT. Além disso, através da técnica de composições, também foi investigado o desempenho do RegCM4 em reproduzir os padrões espaciais anômalos de precipitação sazonal em associação aos episódios ENOS, e as fases do gradiente térmico sobre o Atlântico intertropical. Os resultados demonstraram que o modelo conseguiu representar realisticamente bem o padrão espacial das anomalias pluviométricas acima (abaixo) do normal em grande parte da Amazônia oriental, durante os conhecidos cenários favoráveis, i.e., condições de La Niña e gradiente de aTSM para o Atlântico sul (desfavoráveis, i.e., El Niño e gradiente de aTSM para o Atlântico norte). A B S T R A C T This paper presents a contribution to studies of climate modeling with emphasis on seasonal rainfall variability in the state of Pará, during the summer and autumn (DJF and MAM). Based on the results of simulations of regional RegCM4 for El Niño years (1982/83) and La Niña (1988/89) using the field at high spatial resolution (40 km) and two different convection schemes (Grell and MIT), was investigated the performance of the model to simulate the regional distribution of seasonal rainfall in the state of Pará. The quantitative analysis showed that the RegCM4 presents systematic errors, especially those related to an underestimation of rain in three grades (G1, G2, G3) for the years of El Niño and La Niña are representative only in small areas in the southeastern state in summer period for the Grell scheme, and was more representative of the grid G2 for the year of El Niño in the MIT scheme. Moreover, using the technique of composition, was also investigated in the performance of RegCM4 reproduce the spatial patterns of anomalous seasonal rainfall in association with ENSO episodes and phases of the thermal gradient over the Atlantic intertropical. The results showed that the model represented realistically and spatial patterns of rainfall anomalies above (below) of normal in much of the eastern Amazon, during the known favorable scenarios, ie, La Niña and gradient SSTa South Atlantic (unfavorable, ie, El Niño and gradient SSTa North Atlantic). Keywords: seasonal rainfall, El Nino, La Nina, Amazon, ENSO, RegCM4.

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Maity, Suman, Sridhara Nayak, Kuvar Satya Singh, Hara Prasad Nayak i Soma Dutta. "Impact of Soil Moisture Initialization in the Simulation of Indian Summer Monsoon Using RegCM4". Atmosphere 12, nr 9 (5.09.2021): 1148. http://dx.doi.org/10.3390/atmos12091148.

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Soil moisture is one of the key components of land surface processes and a potential source of atmospheric predictability that has received little attention in regional scale studies. In this study, an attempt was made to investigate the impact of soil moisture on Indian summer monsoon simulation using a regional model. We conducted seasonal simulations using a regional climate model (RegCM4) for two different years, viz., 2002 (deficit) and 2011 (normal). The model was forced to initialize with the high-resolution satellite-derived soil moisture data obtained from the Climate Change Initiative (CCI) of the European Space Agency (ESA) by replacing the default static soil moisture. Simulated results were validated against high-resolution surface temperature and rainfall analysis datasets from the India Meteorology Department (IMD). Careful examination revealed significant advancement in the RegCM4 simulation when initialized with soil moisture data from ESA-CCI despite having regional biases. In general, the model exhibited slightly higher soil moisture than observation, RegCM4 with ESA setup showed lower soil moisture than the default one. Model ability was relatively better in capturing surface temperature distribution when initialized with high-resolution soil moisture data. Rainfall biases over India and homogeneous regions were significantly improved with the use of ESA-CCI soil moisture data. Several statistical measures such as temporal correlation, standard deviation, equitable threat score (ETS), etc. were also employed for the assessment. ETS values were found to be better in 2011 and higher in the simulation with the ESA setup. However, RegCM4 was still unable to enhance its ability in simulating temporal variation of rainfall adequately. Although initializing with the soil moisture data from the satellite performed relatively better in a normal monsoon year (2011) but had limitations in simulating different epochs of monsoon in an extreme year (2002). Thus, the study concluded that the simulation of the Indian summer monsoon was improved by using RegCM4 initialized with high-resolution satellite soil moisture data although having limitations in predicting temporal variability. The study suggests that soil moisture initialization has a critical impact on the accurate prediction of atmospheric circulation processes and convective rainfall activity.

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Xue-Jie, Gao, Wang Mei-Li i Filippo Giorgi. "Climate Change over China in the 21st Century as Simulated by BCC_CSM1.1-RegCM4.0". Atmospheric and Oceanic Science Letters 6, nr 5 (styczeń 2013): 381–86. http://dx.doi.org/10.1080/16742834.2013.11447112.

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Ozturk, Tugba, M. Tufan Turp, Murat Türkeş i M. Levent Kurnaz. "Future projections of temperature and precipitation climatology for CORDEX-MENA domain using RegCM4.4". Atmospheric Research 206 (lipiec 2018): 87–107. http://dx.doi.org/10.1016/j.atmosres.2018.02.009.

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Suh, Myoung-Seok, Seok-Geun Oh i Tae-Jun Kim. "Simulation Skills of RegCM4 for Diurnal Variations of Temperature and Precipitation over South Korea according to the Boundary Conditions". Journal of Climate Research 13, nr 1 (31.03.2018): 51–69. http://dx.doi.org/10.14383/cri.2018.13.1.51.

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Liu, Di, Guiling Wang, Rui Mei, Zhongbo Yu i Huanghe Gu. "Diagnosing the Strength of Land–Atmosphere Coupling at Subseasonal to Seasonal Time Scales in Asia". Journal of Hydrometeorology 15, nr 1 (1.02.2014): 320–39. http://dx.doi.org/10.1175/jhm-d-13-0104.1.

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Abstract This paper focuses on diagnosing the strength of soil moisture–atmosphere coupling at subseasonal to seasonal time scales over Asia using two different approaches: the conditional correlation approach [applied to the Global Land Data Assimilation System (GLDAS) data, the Climate Forecast System Reanalysis (CFSR) data, and output from the regional climate model, version 4 (RegCM4)] and the Global Land–Atmosphere Coupling Experiment (GLACE) approach applied to the RegCM4. The conditional correlation indicators derived from the model output and the two observational/reanalysis datasets agree fairly well with each other in the spatial pattern of the land–atmosphere coupling signal, although the signal in CFSR data is stronger and spatially more extensive than the GLDAS data and the RegCM4 output. Based on the impact of soil moisture on 2-m air temperature, the land–atmosphere coupling hotspots common to all three data sources include the Indochina region in spring and summer, the India region in summer and fall, and north-northeastern China and southwestern Siberia in summer. For precipitation, all data sources produce a weak and spatially scattered signal, indicating the lack of any strong coupling between soil moisture and precipitation, for both precipitation amount and frequency. Both the GLACE approach and the conditional correlation approach (applied to all three data sources) identify evaporation and evaporative fraction as important links for the coupling between soil moisture and precipitation/temperature. Results on soil moisture–temperature coupling strength from the GLACE-type experiment using RegCM4 are in good agreement with those from the conditional correlation analysis applied to output from the same model, despite substantial differences between the two approaches in the terrestrial segment of the land–atmosphere coupling.

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Tesfaye, M., J. Botai, V. Sivakumar i G. Mengistu Tsidu. "Evaluation of Regional Climatic Model Simulated Aerosol Optical Properties over South Africa Using Ground-Based and Satellite Observations". ISRN Atmospheric Sciences 2013 (10.11.2013): 1–17. http://dx.doi.org/10.1155/2013/237483.

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The present study evaluates the aerosol optical property computing performance of the Regional Climate Model (RegCM4) which is interactively coupled with anthropogenic-desert dust schemes, in South Africa. The validation was carried out by comparing RegCM4 estimated: aerosol extinction coefficient profile, Aerosol Optical Depth (AOD), and Single Scattering Albedo (SSA) with AERONET, LIDAR, and MISR observations. The results showed that the magnitudes of simulated AOD at the Skukuza station (24°S, 31°E) are within the standard deviation of AERONET and ±25% of MISR observations. Within the latitudinal range of 26.5°S to 24.5°S, simulated AOD and SSA values are within the standard deviation of MISR retrievals. However, within the latitude range of 33.5°S to 27°S, the model exhibited enhanced AOD and SSA values when compared with MISR observations. This is primarily associated with the dry bias in simulated precipitation that leads to the overestimation of dust emission and underestimation of aerosol wet deposition. With respect to LIDAR, the model performed well in capturing the major aerosol extinction profiles. Overall, the results showed that RegCM4 has a good ability in reproducing the major observational features of aerosol optical fields over the area of interest.

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Kim, Tae-Jun, Myoung-Seok Suh i Seok-Geun Oh. "Impact of Land Surface and Cumulus Parameterization Schemes on the Simulation Skills of RegCM4.0 over CORDEX-East Asia Phase 2 domain". Journal of Climate Research 12, nr 2 (30.06.2017): 181–97. http://dx.doi.org/10.14383/cri.2017.12.2.181.

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Corrales-Suastegui, Arturo, Osias Ruiz-Alvarez, José Abraham Torres-Alavez i Edgar G. Pavia. "Analysis of Cooling and Heating Degree Days over Mexico in Present and Future Climate". Atmosphere 12, nr 9 (2.09.2021): 1131. http://dx.doi.org/10.3390/atmos12091131.

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One simple way to estimate the relationship between air temperature and the energy needed for heating and cooling is to use the concept of degree day. Cooling degree days (CDD) and heating degree days (HDD) are indicators of the energy required to reach comfort levels and are related directly to energy demands. Therefore, using a novel approach, we examine the current conditions and future projections in degree days over Mexico using observations (Livneh and CPC), ERA5 reanalysis, and simulations from the Regional Climate Model (RegCM4). The RegCM4 experiments were driven by different General Circulation Models for two Representative Concentration Pathways scenarios. We consider three 20-year periods as “present conditions” (1995–2014), “near-future conditions” (2041–2060), and “far-future conditions” (2080–2099). The results suggest that in the future, under the lowest radiative forcing scenario there will be a smaller increase (decrease) in CDD (HDD) for the far-future, as compared to the near-future. This could represent the model’s response to the peak of radiative forcing at mid-century and its subsequent decline. For the highest radiative forcing scenario, we found a greater increase (decrease) in CDD (HDD) for the far-future, which could be explained by the response of the RegCM4 to the warming increase projected for 2100.

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Almazroui. "Climate Extremes over the Arabian Peninsula Using RegCM4 for Present Conditions Forced by Several CMIP5 Models". Atmosphere 10, nr 11 (2.11.2019): 675. http://dx.doi.org/10.3390/atmos10110675.

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This paper investigates the temperature and precipitation extremes over the Arabian Peninsula using data from the regional climate model RegCM4 forced by three Coupled Model Intercomparison Project Phase 5 (CMIP5) models and ERA–Interim reanalysis data. Indices of extremes are calculated using daily temperature and precipitation data at 27 meteorological stations located across Saudi Arabia in line with the suggested procedure from the Expert Team on Climate Change Detection and Indices (ETCCDI) for the present climate (1986–2005) using 1981–2000 as the reference period. The results show that RegCM4 accurately captures the main features of temperature extremes found in surface observations. The results also show that RegCM4 with the CLM land–surface scheme performs better in the simulation of precipitation and minimum temperature, while the BATS scheme is better than CLM in simulating maximum temperature. Among the three CMIP5 models, the two best performing models are found to accurately reproduce the observations in calculating the extreme indices, while the other is not so successful. The reason for the good performance by these two models is that they successfully capture the circulation patterns and the humidity fields, which in turn influence the temperature and precipitation patterns that determine the extremes over the study region.

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Bade, B., D. R. Gyawali i S. Timilsina. "ASSESSING THE IMPACTS OF CLIMATE CHANGE ON THE HYDROLOGY OF THE INDRAWATI RIVER BASIN, NEPAL". ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-5/W2 (5.12.2019): 1–8. http://dx.doi.org/10.5194/isprs-annals-iv-5-w2-1-2019.

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Abstract. This study details climate change assessment of the hydrological regime of Indrawati basin of Nepal. The study uses Soil and Water Assessment Tool (SWAT) model to delineate, discretize and parameterize the Indrawati basin to compute model’s input parameters. The model was then run for 1990–2014 to simulate the discharge at the outlet (Dholalghat). The coefficient of determination R2 and Nash-Sutcliffe (ENS) were used to evaluate model calibration and validation. The results found were satisfactory for the gauging station R2 = 0.951 and ENS = 0.901 for calibration and R2 = 0.937 and. ENS = 0.906 for validation. The calibrated hydrological model was run for the future climate change scenario using the RegCM4-LMDZ4 data and the relative changes with the baseline scenarios were analyzed. The comparison suggests that the historical trend of flow is decreasing at the rate of 0.55 m3/s per year. According to RegCM4-LMDZ4 simulations, the trend is going to continue but at a flatter rate. The decreasing trend is observed to be very less. The characteristic peak flow month in the historical scenario is August but the RegCM4-LMDZ4 led simulated flows suggest a shift in monthly peak to October suggesting decrease in monsoon flows and a subsequent significant increase in flows from October to January.

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