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In order to understand impacts of global warming on dust aerosol over East Asia, a regional climate model (RegCM3) coupled with a dust model is employed to simulate the present (1991–2000, following the observed concentration of the greenhouse gases) and future (2091–2100, following the A1B scenario) dust aerosol. Three experiments are performed over East Asia at a horizontal resolution of 50 km, driven by the outputs from a global model of the Model for Interdisciplinary Research on Climate (MIROC3.2_hires), two without (Exp.1 for the present and Exp.2 for the future) and one with (Exp.3 for the future) the radiative effects of dust aerosols. Effects of climate changes on dust aerosols and the feedback of radiative effects in the future are investigated by comparing differences of Exp.2 and Exp.1, Exp.3 and Exp.2, respectively. Results show that global warming will lead to the increases of dust emissions and column burden by 2% and 14% over East Asia, characterized by the increase in December–January–February–March (DJFM) and the decrease in April–May (AM). Similar variations are also seen in the projected frequencies of high dust emission events, showing an advanced active season of dust in the future. The net top-of-atmosphere (TOA) radiative forcing is positive over the desert source regions and negative over downwind regions, while the surface radiative forcing is negative over the domain, which will lead to a reduction of dust emissions and column burden.

Viticulture represents an important economic activity for Greek agriculture. Winegrapes are cultivated in many areas covering the whole Greek territory, due to the favorable soil and climatic conditions. Given the dependence of viticulture on climate, the vitivinicultural sector is expected to be affected by possible climatic changes. The present study is set out to investigate the impacts of climatic change in Greek viticulture, using nine bioclimatic indices for the period 1981-2100. For this purpose, reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and data from the regional climatic model Regional Climate Model Version 3 (RegCM3) are used. It was found that the examined regional climate model estimates satisfactorily these bioclimatic indices. The results of the study show that the increasing trend of temperature and drought will affect all wine-producing regions in Greece. In vineyards in mountainous regions, the impact is positive, while in islands and coastal regions, it is negative. Overall, it should be highlighted that for the first time that Greece is classified into common climatic characteristic categories, according to the international Geoviticulture Multicriteria Climatic Classification System (MCC system). According to the proposed classification, Greek viticulture regions are estimated to have similar climatic characteristics with the warmer wine-producing regions of the world up to the end of twenty-first century. Wine growers and winemakers should take the findings of the study under consideration in order to take measures for Greek wine sector adaptation and the continuation of high-quality wine production. [ABSTRACT FROM AUTHOR]

Human activities have caused substantial land use/cover change (LUCC) in China, especially in northeast China, the Loess Plateau and southern China. Three high-resolution regional climate models were used to simulate the impacts of LUCC on climate through one control experiment and three land use change experiments from 1980 to 2000. The results showed that multi-regional climate model ensemble simulations (the arithmetic ensemble mean (AEM) and Bayesian model averaging (BMA)) provide more accurate results than a single model in over 70% grid cells of study regions. Uncertainty was reduced when using the two ensemble methods. The results of the AEM and BMA ensembles showed that the temperatures decreased by 0.2–0.4 °C in northeast China, the Yangtze river valley and the north of the Loess Plateau, and by 0.6–1.0 °C in the south of the Loess Plateau in spring, autumn and winter. The AEM precipitations changed by − 40–40 mm in in spring and winter, and by − 100–100 mm in summer and autumn, while the BMA precipitations changed by − 20–20 mm in spring, autumn and winter, and by − 50–50 mm in summer. The seasonal precipitation decreased in northeast China and the Yangtze river valley, and increased in the Loess Plateau in most grid cells of study regions. Winter and spring precipitation decreased more in the Yangtze river valley and the Loess Plateau than in northeast China. [ABSTRACT FROM AUTHOR]

O presente estudo tenta trazer um novo ponto de vista sobre a importância do Oceano Atlântico Equatorial no padrão sazonal, durante o período de verão e de outono da região Amazônica. Desta maneira, contribui de uma forma diferente para os estudos na área de modelagem climática e variabilidade pluviométrica na região. Para isto, foi utilizado o modelo RegCM3, com esquema de convecção Grell, aplicando a técnica donwscaling e utilizando como condição inicial os dados de reanalise do NCEP/NCAR. Após a obtenção das simulações foi aplicado o método estatístico Viés para avaliar o quanto o modelo consegue reproduzir a precipitação sazonal. Em uma primeira análise, constata-se que o modelo é sensível a entrada de SF ou ZCAS, bem como, aproxima-se da dinâmica dos trópicos e extratropicos. Os resultados sugerem que a baixa resolução e a parametrização Grell são os principais fatores para a inadequação da qualidade das simulações. Apesar de o esquema Grell ser indicado para regiões com intensa convecção e fortes movimentos verticais, o mesmo necessita ser ajustado com as características físicas da região. Este estudo contribuiu para o aprimoramento dos modelos climáticos regionais para a região amazônica, considerando a contribuição dos processos oceano-atmosfera, durante o período de verão e outono do hemisfério sul.The present study tries to bring a new perspective of the Equatorial Atlantic Ocean importance on seasonal pattern, during the summer and fall on the Amazon region. It contributes in a different way for studies in the area of climate modeling and variability of rainfall over the region. For this study, we used the model RegCM3 with Grell convection scheme, applying the donwscaling technique and using, as initial condition, NCEP/NCAR reanalysis data. After the simulations statistical method of the Bias was applied to evaluate how the accurately the model can reproduce the reanalysis seasonal rainfall. In a first analysis, it appears that the model is sensitive to FS or SAZC occurrences, as well as approaching the dynamics of the tropics and extratropics. The results suggest that the low resolution and the Grell parameterization are the main factors for inadequate quality of the simulations. Although the Grell scheme is suitable for areas with intense convection and strong vertical movements, an adjustment to the physical characteristics of the region is required. This study contributed to the improvement of regional climate models for the Amazon region, considering the contribution of ocean-atmosphere processes, during the summer and autumn in the southern hemisphere.

O presente trabalho apresenta uma contribuição aos estudos de modelagem climática com ênfase na variabilidade pluviométrica sazonal da Amazônia oriental, durante as estações de verão e outono (DJF e MAM). Baseado nos resultados das simulações regionais do RegCM3 para um período de 26 anos (1982/83 a 2007/08) e usando domínio em alta resolução espacial (30 Km) e dois diferentes esquemas de convecção (Grell e MIT), foi investigado o desempenho do modelo em simular a distribuição regional de precipitação sazonal na Amazônia oriental, com referência a um novo conjunto de dados observacional compilado com informações de uma ampla rede integrada de estações pluviométricas. As análises quantitativas evidenciaram que o RegCM3 apresenta erros sistemáticos, sobretudo aqueles relacionados com viés seco no Amapá e norte/nordeste do Pará usando ambos os esquemas Grell e MIT, os quais apontam que o modelo não reproduz as características da ZCIT sobre o Atlântico equatorial. As simulações usando MIT, também apresentaram viés úmido no sudoeste/sul/sudeste do Pará e norte do Tocantins. Além disso, através da técnica de composições, também foi investigado o desempenho do RegCM3 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).This paper presents a contribution on the climate modelling studies with emphasis on seasonal rainfall variability in eastern Amazonia, during the austral summer and autumn seasons (DJF and MAM). Based on RegCM3 regional climate simulations for a 26 years period (1982/83 to 2007/08) using high resolution domain scale (30 km) and two different convection schemes (Grell and MIT), it was investigated the model performance to simulate the regional pluviometric distribution in eastern Amazon, with reference to a new observational data base containing regional aspects extracted from a dense rain gauge station network. The quantitative analysis showed that RegCM3 presents systematic errors, especially those related to the dry bias in the Amapá and north/northeast of Pará using both schemes Grell and MIT, which indicate that the model does not reproduce ITCZ characteristics over equatorial Atlantic. The simulations using MIT also indicated wet bias in the southwest/south/southeast of Pará and north of Tocantins. Moreover, through composites technique, it was also investigated RegCM3 response to reproduce the anomalous spatial rainfall patterns in association with ENSO episodes and interhemispheric SSTa gradient phases across the intertropical Atlantic. The results showed that the model represented realistically well the spatial pattern related to the rainfall anomalies above (below) than normal in most of eastern Amazonia, during the known favourable scenarios, i.e., La Niña and south Atlantic SSTa gradient (unfavourable, i.e., El Niño and north Atlantic SSTa gradient).

Regional climate models such as RegCM3 are capable to simulating different climate processes. Modeling the climate can detect differences between real climate and model-simulated climate in the area under study. Variety of simulations have been done for sensitivity investigation of the model to the physical computational processes and schemes such as radiation, convection, land use, resolution, domain size and center of domain. In this work, sensitivity of the RegCM3 has been measured to the different convective schemes including Grell, modified Kuo and Emanuel. Grell scheme itself has been divided into two different schemes of Arakawa-Schubert (AS) and Fritch-Chapel (FC). Winters (started from Decembers up to February) of 1997 and 2000 were the period of study. Model operation in producing the monthly amount of precipitation was calculated by comparing model output with observed precipitation of 151 synoptic stations of Iran and CRU reanalysis data. According to the results of this research, the regional appropriate schemes with their errors are: Kuo with -%24 error for the southeast, Kuo with %16.5 error for the northeast, Emanuel with %85 error for the central part of Iran, Kuo with %20 error for southwest, Emanuel with -%10 error for west, Grell-FC and Kuo with -%80 error for the northeast and Kuo with -%16 error for the southwest of Caspian Sea. Simulation's errors for the central and the northwestern parts of Iran have been rejected statistically because of high amount of errors. But according to mean error analysis of two years simulations, Grell schemes with approximately % 20 errors have good results for winter precipitation simulation of Iran.

Relationship between rainfall and tropospheric temperature (TT) has been examined over the Indian subcontinent during four seasons of the year using Regional Climate Model Version 3.0 (RegCM3). The model has been integrated at 55 km horizontal resolution over India during the years 1980-2000 with prescribed lateral boundary forcing from the 40 years re-analysis (ERA40) of the European Centre for Medium-range Weather Forecasts. Results of this study show that RegCM3 in general is able to capture the spatial distributions of rainfall in all the seasons as compared to the corresponding IMD0.5 gridded rainfall. The model has simulated warmer TT over the Himalayan region in all the seasons as compared to ERA40. However, it is well captured over the peninsular India and the oceanic regions. In the model, larger warming by about 0.5 °C over the northwest and Central India in the summer monsoon months might have lead to lower surface pressure there. Also, the vertical extent of the monsoon trough is found to be up to 500 hPa in the model as compared to that in NCEP/NCAR reanalysis. As a consequence, the simulated monsoon circulation and rainfall are stronger than those observed. The two most important rainfall seasons, the summer monsoon and winter are reasonably well simulated with correlation coefficients (CC) of 0.60 and 0.59 respectively significant at 99 % confidence level with the corresponding observed values of IMD0.5. Further, Indian summer monsoon rainfall (ISMR) and TT during the contrasting monsoon years are also close to their respective observed values. Temporal CCs between the TT over Tibet, Pakistan and Central India during the summer monsoon season and gridded ISMR values reveals that the TT over Pakistan has been better correlated with the ISMR than those over Tibet and Central India. This relationship has been well supported by the model simulations. [ABSTRACT FROM AUTHOR]

Occupational fatalities and work-related injuries are more common in Turkey than in most developing and developed countries. Several precautions have been taken concerning the matter, and The Occupational Health and Safety Act (OHSL ) has been passed. These efforts, however, have failed to incorporate in their framework the role of global warming. New legislation is underway for the prevention of occupational diseases, injuries, and fatalities. This is particularly worrisome given that Turkey is in the forefront of countries projected to be affected seriously by climate change. Consequently, a study on the direct and indirect impact of climate change on workers' health and labour productivity is paramount. The main purpose of this research is to present diminishing labour productivity as a consequence of decreased working hours via an estimate of rest hours of workers in manual labour. The climatic outputs of Regional Climate Model (RegCM3) obtained from the ENSEMBLES Project are used to calculate the wet bulb globe temperature (WBGT) over western Turkey. The study covers the span of years between 1971 and 2100. Moreover, spatial distributions of observed domain are estimated by means of a seasonal analysis, preliminary to a more detailed research. Critical regions, more adversely influenced than others, are identified. The total number of loss days for these critical regions are presented for various time periods. As a result, labour productivity particularly in agriculture and construction is expected to diminish seriously over Central Anatolia, Cyprus, and parts of the Aegean and eastern Mediterranean coastal areas. Between 2071 and 2100, deficiency in labour productivity may reach up to 52 % during the summer across some of these critical regions. Though it will be seen that the present study has focused primarily on manual labour and outdoor work in particular, it foreshadows nevertheless the dangerous impact of climate change on occupational health and labour productivity in general. [ABSTRACT FROM AUTHOR]

ABSTRACT This study evaluates the capability of a Climate-Crop Modelling System ( RegCM3-GLAM) in simulating the regional climate and crop yields (maize, rice, cowpea, and groundnut) over Nigeria. Daily climatic data obtained from a Regional Climate Model ( RegCM3) simulation was used as the input data in the General Large Area Model ( GLAM) to simulate the crop yields for 11 years (1999-2009), and a series of sensitivity experiments were performed to test and optimize the GLAM parameters over the region. The results show that RegCM3 gives a realistic simulation of the Nigerian climate. The correlation coefficients obtained between the observed and simulated climatic variables are between 0.72 and 0.96 at p < 0.01. However, the model slightly underestimates rainfall and maximum temperature in the wet season (April to October) and overestimates rainfall and maximum temperature in the dry season (November to March). GLAM also gives a realistic simulation of the mean and spatial distribution of crop yields in Nigeria. The root mean square errors of the simulations are generally less than 36% of the observed yields. The performance evaluation of the model varies with ecological zones. The model shows the best performance in simulating maize and the worst performance in simulating cowpea over the Savannas. Sensitivity experiments reveal that simulated crop yield is sensitive to model parameters (harvest index, extinction coefficient, optimum temperature, and transpiration efficiency), with both extinction coefficient and transpiration efficiency showing more significant impact. It has been concluded that the performance of GLAM over the country can be further improved by enhancing the quality of meteorological input data. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the impact of the horizontal resolution of a RegCM3 (Regional Climate Model version 3) in order to reproduce local features of climate, particularly fog, in the Metropolitan Area of São Paulo (MASP), Brazil. RegCM3 simulations with horizontal resolutions of 50 km (R50) and 20 km (R20) are conducted for 2003 and 2004 austral winters, June to September (JJAS). Simulations are compared with both gridded analysis and station observations. An objective criterion, is used in the simulations (applied at 09 and 21 local time) to search fog events based on relative humidity and precipitation thresholds in order to identify mainly radiation fog formation. The overall result shows improvements in order to reproduce the local climate using the finest resolution simulation, since R20 simulates better the observed spatial patterns. The evaluations of the daily mean air temperature, relative humidity, and pressure show that both R50 and R20 simulate mean values comparable to the local observations of MASP. Firstly, there is high time correlation and small root mean square error for air temperature (mean, maximum and minimum) using R20 simulation. Additionally, R20 reduces the rainfall overestimation of R50 due to the more realistic representation of topography and coastlines. Both R20 and R50 are able to simulate the fog event frequency similar to the observed ones during 2003 and 2004 JJAS periods, with overestimation below 10%. Local observation and simulations (R50 and R20) present a higher frequency of fog in 2003 than 2004. Regarding fog characteristic, it is found that: (1) stations located in the valleys as well as coastal areas have different patterns with the first ones presenting higher frequency of fog events; (2) the atmospheric variable errors during fog events are clearly smaller than for the whole JJAS period; (3) it is simulated properly for the relative humidity increase, temperature decrease and small specific humidity increase during fog events; and (4) the synoptic pattern during fog event can be clearly characterized by R20 simulation. Therefore, R20 and R50 indicate the modeling ability in order to characterize fog events over MASP. [ABSTRACT FROM AUTHOR]

Low level atmospheric circulations downscaled by regional climate model are used to identify austral summer (December-January-February) weather regimes (WRs) over central Brazil. For the period 1989-2006, the Kohonen's self-organizing maps method is applied to provide simulated weather patterns and their relationship with daily rainfall. Six WRs were defined: two related to the active phase of the South American monsoon system (SAMS), with the large occurrence of days with extreme rainfall; two related to the break phase and few occurrences of extreme rainfall; and two others resembling transient WRs, those with fewer extreme rainfall. The WRs formed a cycle obtained from their transition probabilities, which suggests alternating phases of the convergence zone and their association with extreme rainfall. Thus, the variability of summer precipitation, related to the behavior of the simulated WRs enables the verification of the regional dynamic model on intraseasonal time scale. [ABSTRACT FROM AUTHOR]

Tourism is one of the most important economic sectors in Croatia. The Adriatic coast is a popular travel destination for tourists, especially during the summer months. During their activities, tourists are affected by atmospheric conditions and therefore by weather and climate. Therefore, it is important to have reliable information about thermal conditions as well as their impacts on human beings. Here, the climate tourism potential of Croatia is presented and quantified on the basis of three selected stations in different climatic regions. The physiologically equivalent temperature is used for analysis as well as other climatic parameters relevant for tourism and recreation. The results already point to hot conditions for outdoor activities in summer during afternoons, especially along the coast but also for continental regions, resulting in a reduction of the climate tourism potential. In the future, this trend looks set to increase, possibly leading to a changing tourism sector in Croatia requiring adaptation and new strategies. [ABSTRACT FROM AUTHOR]

A key question for climate mitigation and adaptation decisions is how quickly significant changes in temperature extremes will emerge as greenhouse gas concentrations increase, and whether that emergence will be uniform between hot and cold extremes and across different geographic areas. We use a high-resolution, multi-member ensemble climate model experiment over the United States (U.S.) to investigate the transient response of the annual frequency, duration and magnitude of 8 daily-scale extreme temperature indices during the twenty-first century of the A1B emissions scenario. We evaluate the time of emergence of a permanent exceedance (PE) above the colder part of the historical (1980-2009) extremes distribution, and the time of emergence of a new norm (NN) centered on the historical maxima (for hot extremes) or minima (for cold extremes). We find that during the twenty-first century, hot extremes permanently exceed the historical distribution's colder half over large areas of the U.S., and that the hot extremes distribution also becomes centered on or above the historical distribution's maxima. The changes are particularly robust for the exceedance of the annual 95th percentile of daily maximum temperature over the West and the Northeast (with the earliest emergence of a PE by 2030 and of a NN by 2040), for warm days over the Southwest (with the earliest emergence of a PE by 2020 and of a NN by 2030), and tropical nights over the eastern U.S. (with the earliest emergence of a PE by 2020 and of a NN by 2030). Conversely, no widespread emergence of a PE or a NN is found for most cold extremes. Exceptions include frost day frequency (with a widespread emergence of a PE below the historical median frequency by 2030 and of a NN by 2040 over the western U.S.), and cold night frequency (with an emergence of a PE below the historical median frequency by 2040 and of a NN by 2060 in virtually the entire U.S.). Our analysis implies a transition over the next half century to a climate of recently unprecedented heat stress in many parts of the U.S., along with cold extremes that, although less frequent, remain at times as long and as severe as are found in the current climate. [ABSTRACT FROM AUTHOR]

Climate changes over China from the present (1990-1999) to future (2046-2055) under the A1FI (fossil fuel intensive) and A1B (balanced) emission scenarios are projected using the Regional Climate Model version 3 (RegCM3) nests with the National Center for Atmospheric Research (NCAR) Community Climate System Model (CCSM). For the present climate, RegCM3 downscaling corrects several major deficiencies in the driving CCSM, especially the wet and cold biases over the Sichuan Basin. As compared with CCSM, RegCM3 produces systematic higher spatial pattern correlation coefficients with observations for precipitation and surface air temperature except during winter. The projected future precipitation changes differ largely between CCSM and RegCM3, with strong regional and seasonal dependence. The RegCM3 downscaling produces larger regional precipitation trends (both decreases and increases) than the driving CCSM. Contrast to substantial trend differences projected by CCSM, RegCM3 produces similar precipitation spatial patterns under different scenarios except autumn. Surface air temperature is projected to consistently increase by both CCSM and RegCM3, with greater warming under A1FI than A1B. The result demonstrates that different scenarios can induce large uncertainties even with the same RCM-GCM nesting system. Largest temperature increases are projected in the Tibetan Plateau during winter and high-latitude areas in the northern China during summer under both scenarios. This indicates that high elevation and northern regions are more vulnerable to climate change. Notable discrepancies for precipitation and surface air temperature simulated by RegCM3 with the driving conditions of CCSM versus the model for interdisciplinary research on climate under the same A1B scenario further complicated the uncertainty issue. The geographic distributions for precipitation difference among various simulations are very similar between the present and future climate with very high spatial pattern correlation coefficients. The result suggests that the model present climate biases are systematically propagate into the future climate projections. The impacts of the model present biases on projected future trends are, however, highly nonlinear and regional specific, and thus cannot be simply removed by a linear method. A model with more realistic present climate simulations is anticipated to yield future climate projections with higher credibility. [ABSTRACT FROM AUTHOR]

Abstract: The regional and temporal characteristics of the Indian Summer Monsoon Rainfall (ISMR) over the whole country as well as in its six rainfall homogenous zones have been studied using Regional Climate Model Version 3.0 (RegCM3). The model is integrated at 55km horizontal resolution over India during the years 1980 to 2000 with prescribed lateral boundary forcing from ECMWF 40Year Re-Analysis (ERA40). The rainfall over the country as a whole has been overestimated by the model in comparison to observed India Meteorological Department (IMD) rainfall dataset. The model is able to capture the rainfall characteristics during 50% of observed Deficient years, 67% of Excess years, 71% of Normal years, 75% of El-Nino years and all of the La-Nina years. Analysis shows that the interannual variation of simulated ISMR bears good correlation coefficients of 0.66, 0.57 and 0.57 significant at 1% and 0.47 significant at 5% with the observed values over four rainfall homogenous zones West Central India, Central Northeast India, North West India and Hilly region respectively. The performance of RegCM3 in simulating various phases of drought conditions using Standardized Precipitation Index (SPI) has also been examined. The SPI is well captured by the model over the same four zones. The model performance has further been evaluated by analyzing the onset, withdrawal dates and Length of Rainy Season (LRS) of Indian summer monsoon during the period of study by normalizing the spatial mean of Vertically Integrated Moisture Transport (VIMT) over Arabian Sea. Results show that the onset has been delayed by 5days while the withdrawal is delayed by 23days as compared to NCEP/NCAR reanalysis in the total period of study. The simulated average LRS is 11days more than the observed. The excess rainfall over Indian subcontinent might be attributed to the surplus moisture flux over the Arabian Sea till the last week of September. As a consequence, RegCM3 has simulated longer duration of rainy season. [Copyright &y& Elsevier]

A regional atmosphere-ocean coupled model, RegCM3-POM, was developed by coupling the regional climate model (RegCM3) with the Princeton Ocean Model (POM). The performance of RegCM3-POM in simulating a persistent snow storm over southern China and the impact of the Madden-Julian oscillation (MJO) on this persistent snow storm were investigated. Compared with the stand-alone RegCM3, the coupled model performed better at reproducing the spatial-temporal evolution and intensity of the precipitation episodes. The power spectral analysis indicated that the coupled model successfully captured the dominant period between 30 and 60 days in the precipitation field, leading to a notable improvement in simulating the magnitude of intraseasonal precipitation variation, and further in enhancing the intensity of the simulated precipitation. These improvements were mainly due to the well-simulated low-frequency oscillation center and its eastward propagation characteristics in each MJO phase by RegCM3-POM, which improved the simulations of MJO-related low-frequency vertical motions, water vapor transport, and the deep inversion layer that can directly influence the precipitation event and that further improved the simulated MJO-precipitation relationship. Analysis of the phase relationship between convection and SST indicated that RegCM3-POM exhibits a near-quadrature relation between the simulated convection and SST anomalies, which was consistent with the observations. However, such a near-quadrature relation was not as significant when the stand-alone RegCM3 was used. This difference indicated that the inherent coupled feedback process between the ocean and atmosphere in RegCM3-POM played an important part in reproducing the features of the MJO that accompanied the snow storm. [ABSTRACT FROM AUTHOR]

This work investigates the distribution of high winds above Beaufort scale 6 in the offshore zones of China using high-resolution satellite measurements. A numerical experiment is carried out in order to find out the effects of Taiwan Island on the formation of strong winds. The analysis indicates that the distribution of high wind occurrence is similar to that of the average wind velocity in winter. High winds tend to be anchored in special topographical regions, such as the Taiwan Strait, the Bashi Channel and the southeast coast of Vietnam. High winds occur much more frequently over the warmer than the colder flank of Kuroshio front as it meanders from Taiwan to Japan. The frequency of high winds decreases drastically in spring. The Taiwan Strait maintains the largest high wind occurrence. Besides, high winds remain frequent in the Bashi Channel, the southeast tip of Taiwan Island and the warmer flank of Kuroshio front. In summer, high winds generally occur infrequently except over a broad region off the southeast coast of Vietnam near 10°N and the frequency there decreases from southwest to northeast. High winds around Taiwan Island present near axisymmetric distribution with larger frequency along southeast-northwest direction and smaller frequency along southwest-northeast direction. The dominant direction of high winds exhibits a counterclockwise circulation surrounding the island. The frequency of high winds increases rapidly in autumn and almost repeats the distribution that appears in winter. The simulation results suggest that the effects of Taiwan Island topography on high winds vary with seasons. In winter, topography is the major cause of high winds in the surrounding oceanic zones. High winds in both Taiwan Strait and the southeast corner of the island disappear and the frequency decreases gradually from south to north when the terrain is removed. However, in summer, high wind frequency derived from two simulations with and without terrain is almost identical. We attribute this phenomenon to the factors which are responsible for the formation of high winds. [ABSTRACT FROM AUTHOR]

We explore the potential to improve understanding of the climate system by directly targeting climate model analyses at specific indicators of climate change impact. Using the temperature suitability of premium winegrape cultivation as a climate impacts indicator, we quantify the inter- and intra-ensemble spread in three climate model ensembles: a physically uniform multi-member ensemble consisting of the RegCM3 high-resolution climate model nested within the NCAR CCSM3 global climate model; the multi-model NARCCAP ensemble consisting of single realizations of multiple high-resolution climate models nested within multiple global climate models; and the multi-model CMIP3 ensemble consisting of realizations of multiple global climate models. We find that the temperature suitability for premium winegrape cultivation is substantially reduced throughout the high-value growing areas of California and the Columbia Valley region (eastern Oregon and Washington) in all three ensembles in response to changes in temperature projected for the mid-twenty first century period. The reductions in temperature suitability are driven primarily by projected increases in mean growing season temperature and occurrence of growing season severe hot days. The intra-ensemble spread in the simulated climate change impact is smaller in the single-model ensemble than in the multi-model ensembles, suggesting that the uncertainty arising from internal climate system variability is smaller than the uncertainty arising from climate model formulation. In addition, the intra-ensemble spread is similar in the NARCCAP nested climate model ensemble and the CMIP3 global climate model ensemble, suggesting that the uncertainty arising from the model formulation of fine-scale climate processes is not smaller than the uncertainty arising from the formulation of large-scale climate processes. Correction of climate model biases substantially reduces both the inter- and intra-ensemble spread in projected climate change impact, particularly for the multi-model ensembles, suggesting that-at least for some systems-the projected impacts of climate change could be more robust than the projected climate change. Extension of this impacts-based analysis to a larger suite of impacts indicators will deepen our understanding of future climate change uncertainty by focusing on the climate phenomena that most directly influence natural and human systems. [ABSTRACT FROM AUTHOR]

The regional climate model RegCM3 has been one-way nested into IAP9L-AGCM, the nine-level atmospheric general circulation model of the Institute of Atmospheric Physics, Chinese Academy of Sciences, to perform a 20-yr (1982-2001) hindcast experiment on extraseaonal short-term prediction of China summer climate. The nested prediction system is referred to as RegCM3_IAP9L-AGCM in this paper. The results show that hindcasted climate fields such as 500-hPa geopotential height, 200- and 850-hPa zonal winds from RegCM3_IAP9L-AGCM have positive anomaly correlation coefficients (ACCs) with the observations, and are better than those from the stand-alone IAP9L-AGCM. Except for the 850-hPa wind field, the positive ACCs of the other two fields with observations both pass the 90% confidence level and display a zonal distribution. The results indicate that the positive correlation of summer precipitation anomaly percentage between the nested prediction system and observations covers most parts of China except for downstream of the Yangtze River and north of Northeast and Northwest China. The nested prediction system and the IAP9L-AGCM exhibit different hindcast skills over different regions of China, and the former demonstrates a higher skill over South China than the latter in predicting the summer precipitation. [ABSTRACT FROM AUTHOR]

Effects of the increased sea surface temperatures (SSTs) in the surrounding seas of the Anatolian Peninsula on the precipitation it receives are investigated through sensitivity simulations using a state-of-the-art regional climate model, RegCM3. The sensitivity simulations involve 2-K increases to the SSTs of the Aegean, eastern Mediterranean and Black seas individually as well as collectively. All the simulations are integrated over a 10-year period between 1990 and 2000. The model simulations of this study indicate that the precipitation of the peninsula is sensitive to the variations of the SSTs of the surrounding seas. In general, increased SSTs lead to increases in the precipitation of the peninsula as well as that of the seas considered. The statistically significant increases at 95% confidence levels largely occur along the coastal areas of the peninsula that are in the downwind side of the seas. Significant increases do also take place in the interior areas of the peninsula, especially in the eastern Anatolia in winter. The simulations reveal that eastern Mediterranean Sea has the biggest potential to affect the precipitation in the peninsula. They also demonstrate that taking all three seas into account simultaneously enhances the effect of SSTs on the peninsula's precipitation, and extends the areas with statistically significant increases. [ABSTRACT FROM AUTHOR]

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 (ζ) obtained from a 10-m height wind field. All the systems with ζ ≤ −1.5 × 10 s 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 ± 11.2 and 278.7 ± 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 (ζ ≤ −2.5 × 10 s). It was noted that over the SAO the annual cycle of the cyclogenesis depends of its initial intensity. Considering the systems initiate with ζ ≤ −1.5 × 10 s, the annual cycle is not well defined and the higher frequency occurs in the autumn (summer) in the NCEP (RegCM3). The stronger systems (ζ ≤ −2.5 × 10 s) have a well-characterized high frequency of cyclogenesis during the winter in both NCEP and RegCM3. This work confirms the existence of three cyclogenetic regions in the west sector of the SAO, near the South America east coast and shows that RegCM3 is able to reproduce the main features of these cyclogenetic areas. [ABSTRACT FROM AUTHOR]

Aerosol observational data at 8 ground-based observation sites in the Chinese Sun Hazemeter Network (CSHNET) were analyzed to characterize the optical properties of aerosol particles during the strong dust storm of 16–21 April 2005. The observational aerosol optical depth (AOD) increased significantly during this dust storm at sites in Beijing city (86%), Beijing forest (84%), Xianghe (13%), Shapotou (27%), Shenyang (47%), Shanghai (23%), and Jiaozhou Bay (24%). The API (air pollution index) in Beijing and Tianjin also had a similar rise during the dust storm, while the Angström exponent ( α) declined evidently at sites in Beijing city (21%), Beijing forest (39%), Xianghe (19%), Ordos (77%), Shapotou (50%), Shanghai (12%), and Jiaozhou Bay (21%), respectively. Furthermore, The observational AOD and α demonstrated contrary trends during all storm stages (pre-dust storm, dust storm, and post-dust storm), with the AOD indicating an obvious “Valley-Peak-Valley” pattern of variation, while α demonstrated a “Peak-Valley-Peak” pattern. In addition, the dust module in a regional climate model (RegCM3) simulated the dust storm occurrence and track accurately and RegCM3 was able to basically simulate the trends in AOD. The simulation results for the North China stations were the best, and the simulation for dust-source stations was on the high side, while the simulation was on the low side for coastal sites. [ABSTRACT FROM AUTHOR]

Coupling of the Community Land Model (CLM3) to the ICTP Regional Climate Model (RegCM3) substantially improves the simulation of mean climate over West Africa relative to an older version of RegCM3 coupled to the Biosphere Atmosphere Transfer Scheme (BATS). Two 10-year simulations (1992–2001) show that the seasonal timing and magnitude of mean monsoon precipitation more closely match observations when the new land surface scheme is implemented. Specifically, RegCM3–CLM3 improves the timing of the monsoon advance and retreat across the Guinean Coast, and reduces a positive precipitation bias in the Sahel and Northern Africa. As a result, simulated temperatures are higher, thereby reducing the negative temperature bias found in the Guinean Coast and Sahel in RegCM3–BATS. In the RegCM3–BATS simulation, warmer temperatures in northern latitudes and wetter soils near the coast create excessively strong temperature and moist static energy gradients, which shifts the African Easterly Jet further north than observed. In the RegCM3–CLM3 simulation, the migration and position of the African Easterly Jet more closely match reanalysis winds. This improvement is triggered by drier soil conditions in the RegCM3–CLM3 simulation and an increase in evapotranspiration per unit precipitation. These results indicate that atmosphere–land surface coupling has the ability to impact regional-scale circulation and precipitation in regions exhibiting strong hydroclimatic gradients. [ABSTRACT FROM AUTHOR]

A regional coupled atmosphere–ocean model was developed to study the role of air–sea interactions in the simulation of the Indian summer monsoon. The coupled model includes the regional climate model (RegCM3) as atmospheric component and the regional ocean modeling system (ROMS) as oceanic component. The two-way coupled model system exchanges sea surface temperature (SST) from the ocean to the atmospheric model and surface wind stress and energy fluxes from the atmosphere to the ocean model. The coupled model is run for four years 1997, 1998, 2002 and 2003 and the results are compared with observations and atmosphere-only model runs employing Reynolds SSTs as lower boundary condition. It is found that the coupled model captures the main features of the Indian monsoon and simulates a substantially more realistic spatial and temporal distribution of monsoon rainfall compared to the uncoupled atmosphere-only model. The intraseasonal oscillations are also better simulated in the coupled model compared to the atmosphere-only model. These improvements are due to a better representation of the feedbacks between the SST and convection and highlight the importance of air–sea coupling in the simulation of the Indian monsoon. [ABSTRACT FROM AUTHOR]

The article presents a study on the evaluation and adaptation of the Abdus Salam International Center for Theoretical Physics version 3 Regional Climate Model's (ICTP RegCM3) ability to capture the rainfall patterns and interannual variation in the varied region of the Horn of Africa. It mentions that the evaluation of the simulated rainfall was conducted for the four alternative convective schemes including the Modified Anthes-Kuo, the Grell scheme with Arakawa-Schubert closure, the Grell scheme with Fritsch-Chappell closure and the Emanuel scheme. The study reveals that the Emanuel scheme captures best the rainfall patterns and the interannual variability. It suggests that ICTP RegCM3 model can be used to study rainfall processes and variability and downscale seasonal rainfall forecasts.

To test the applicability of cumulus convective parameter schemes in RegCM3 to the rainfall over the Longitudinal Range-Gorge Region (LRGR), the May and the summer rainfalls from 1982 to 2001 were simulated with different cumulus convective parameter schemes in RegCM3. The results of quantitative analysis contrasting simulation rainfall with observational one indicate that Fritsch-Chappell cumulus convective parameter scheme has the best simulation ability to the 20-year total May rainfall over LRGR, and the simulation ability of Anthes-Kuo cumulus convective parameter scheme takes the second place. Anthes-Kuo cumulus convective parameter scheme has the best simulation ability to the 20-year total summer rainfall over LRGR, and the simulation ability of Fritsch-Chappell gets the second place. The total rainfall simulated over LRGR is less than the observational one. The result of simulating interannual variation of May and summer rainfalls over LRGR is almost the same as that of simulating 20-year total rainfall. The Anthes-Kuo and the Fritsch-Chappell cumulus convective parameter schemes adapt to describing cumulus convective process in May and summer over LRGR. [ABSTRACT FROM AUTHOR]

The article presents an analysis of the systematic errors in the simulation of European climate in 1961-2000, performed by the climate model RegCM, version 3 (RegCM3). It compares the model results to the observations by the Climate Research Unit (CRU) and evaluates the average and annual cycle biases for three surface variables: air temperature, precipitation, and water vapor pressure. The use of the RegCm3 for dynamical downscaling of general circulation model (GCM) results for regional climate change projections is also discussed.

We find that extreme temperature and precipitation events are likely to respond substantially to anthropogenically enhanced greenhouse forcing and that fine-scale climate system modifiers are likely to play a critical role in the net response. At present, such events impact a wide variety of natural and human systems, and future changes in their frequency and/or magnitude could have dramatic ecological, economic, and sociological consequences. Our results indicate that fine-scale snow albedo effects influence the response of both hot and cold events and that peak increases in extreme hot events are amplified by surface moisture feedbacks. Likewise, we find that extreme precipitation is enhanced on the lee side of rain shadows and over coastal areas dominated by convective precipitation. We project substantial, spatially heterogeneous increases in both hot and wet events over the contiguous United States by the end of the next century, suggesting that consideration of fine-scale processes is critical for accurate assessment of local-and regional-scale vulnerability to climate change. [ABSTRACT FROM AUTHOR]