Global Change Impact Studies Center
Global Change Impact Studies Center
Dogar M.M.,King Abdullah University of Science and Technology |
Dogar M.M.,Global Change Impact Studies Center |
Kucharski F.,Abdus Salam International Center For Theoretical Physics |
Azharuddin S.,University of Lucknow
Journal of Earth System Science | Year: 2017
ENSO is considered as a strong atmospheric teleconnection that has pronounced global and regional circulation effects. It modifies global monsoon system, especially, Asian and African monsoons. Previous studies suggest that both the frequency and magnitude of ENSO events have increased over the last few decades resulting in a need to study climatic impacts of ENSO magnitude both at global and regional scales. Hence, to better understand the impact of ENSO amplitude over the tropical and extratropical regions focussing on the Asian and African domains, ENSO sensitivity experiments are conducted using ICTPAGCM (‘SPEEDY’). It is anticipated that the tropical Pacific SST forcing will be enough to produce ENSO-induced teleconnection patterns; therefore, the model is forced using NINO3.4 regressed SST anomalies over the tropical Pacific only. SPEEDY reproduces the impact of ENSO over the Pacific, North and South America and African regions very well. However, it underestimates ENSO teleconnection patterns and associated changes over South Asia, particularly in the Indian region, which suggests that the tropical Pacific SST forcing is not sufficient to represent ENSO-induced teleconnection patterns over South Asia. Therefore, SST forcing over the tropical Indian Ocean together with air–sea coupling is also required for better representation of ENSO-induced changes in these regions. Moreover, results obtained by this pacemaker experiment show that ENSO impacts are relatively stronger over the Inter-Tropical Convergence Zone (ITCZ) compared to extratropics and high latitude regions. The positive phase of ENSO causes weakening in rainfall activity over African tropical rain belt, parts of South and Southeast Asia, whereas, the La Niña phase produces more rain over these regions during the summer season. Model results further reveal that ENSO magnitude has a stronger impact over African Sahel and South Asia, especially over the Indian region because of its significant impact over the tropical Atlantic and the Indian Ocean through Walker circulation. ENSO-induced negative (positive) NAO-like response and associated changes over Southern Europe and North Africa get significantly strong following increased intensity of El Niño (La Niña) in the northern (southern) hemisphere in the boreal winter (summer) season. We further find that ENSO magnitude significantly impacts Hadley and Walker circulations. The positive phase of ENSO (El Niño) overall strengthens Hadley cell and a reverse is true for the La Niña phase. ENSO-induced strengthening and weakening of Hadley cell induces significant impact over South Asian and African ITCZ convective regions through modification of ITCZ/monsoon circulation system. © Indian Academy of Sciences.
Gong Z.,National Climate Center |
Dogar M.M.A.,King Abdullah University of Science and Technology |
Dogar M.M.A.,Global Change Impact Studies Center |
Qiao S.,Lanzhou University |
And 2 more authors.
Atmospheric Research | Year: 2017
This study examines the ability of the Beijing Climate Center Climate System Model (BCC_CSM) to predict the meridional pattern of summer precipitation over East Asia-Northwest Pacific (EA-NWP) and its East Asia-Pacific (EAP) teleconnection. The differences of summer precipitation modes of the empirical orthogonal function and the bias of atmospheric circulations over EA-NWP are analyzed to determine the reason for the precipitation prediction errors. Results indicate that the BCC_CSM could not reproduce the positive-negative-positive meridional tripole pattern from south to north that differs markedly from that observed over the last 20 years. This failure can be attributed to the bias of the BCC_CSM hindcasts of the summer EAP teleconnection and the low predictability of 500 hPa at the mid-high latitude lobe of the EAP. Meanwhile, the BCC_CSM hindcasts' deficiencies of atmospheric responses to SST anomalies over the Indonesia maritime continent (IMC) resulted in opposite and geographically shifted geopotential anomalies at 500 hPa as well as wind and vorticity anomalies at 850 hPa, rendering the BCC_CSM unable to correctly reproduce the EAP teleconnection pattern. Understanding these two problems will help further improve BCC_CSM's summer precipitation forecasting ability over EA-NWP. © 2017
Saeed S.,Global Change Impact Studies Center |
Saeed S.,Max Planck Institute for Meteorology |
Liu Y.,Beijing Climate Center
Theoretical and Applied Climatology | Year: 2011
Multiyear (1983-2006) hindcast simulation of summer monsoon over South Asia has been carried out using the regional climate model of the Beijing Climate Centre (BCC_RegCM1. 0). The regional climate model (hereafter BCC RCM) is nested into the global climate model of the Beijing Climate Centre BCC_CGCM1. 0 (here after CGCM). The regional climate model is initialized on 01 May and integrated up to the end of the September for 24 years. Compared to the driving CGCM the BCC RCM reproduces reasonably well the intensity and magnitude of the large-scale features associated with the South Asia summer monsoon such as the upper level anticyclone at 200 hPa, the mid-tropospheric warming over the Tibetan plateau, the surface heat low and the 850 hPa moisture transport from ocean to the land. Both models, i.e., BCC RCM and the driving CGCM overestimates (underestimates) the 850 hPa southwesterly flow over the northern (southern) Arabian Sea. Moreover, both models overestimate the seasonal mean precipitation over much of the South Asia region compared to the observations. However, the precipitation biases are significantly reduced in the BCC RCM simulations. Furthermore, both models simulate reasonably the interannual variability of the summer monsoon over India. The precipitation index simulated by BCC RCM shows significant correlation (0.62) with the observed one. The BCC RCM simulates reasonably well the spatial and temporal variation of the precipitation and surface air temperature compared to the driving CGCM. Further, the temperature biases are significantly reduced (1-4°C) in the BCC RCM simulations. The simulated vertical structure of the atmosphere show biases above the four sub-regions, however, these biases are significantly reduced in the BCC RCM simulations compared to the driving CGCM. Compared to the driving CGCM, the evolution processes of the onset of summer monsoon, e.g., the meridional temperature gradient and the vertical wind shear are well simulated by the BCC RCM. The 24-year simulations also show that with a little exception the BCC RCM is capable to reproduce the monsoon active and break phases and the intraseasonal precipitation variation over the Indian subcontinent. © 2010 Springer-Verlag.
Mir K.A.,National University of Singapore |
Mir K.A.,Global Change Impact Studies Center |
Purohit P.,International Institute For Applied Systems Analysis |
Goldstein G.A.,DecisionWare Group LLC |
Balasubramanian R.,National University of Singapore
Environmental Science and Pollution Research | Year: 2016
This study aims to assess the current and future air pollution and associated health impacts in Pakistan. In this study, the Pakistan Integrated Energy Model (Pak-IEM) is used to assess current and future energy consumption in Pakistan. To assess air pollution levels and associated health impacts, we used the Greenhouse gas and Air pollution INteractions and Synergies (GAINS) model. A linkage has been established between both the models to feed the energy outputs from Pak-IEM into GAINS for exploring different scenarios. Mainly, the emissions of three air pollutants (SO2, NOx, and PM2.5) as well as the associated health impacts of increased emissions are assessed. Baseline emission scenario (BES) shows a growth in emissions of SO2, NOx, and PM2.5 by a factor of 2.4, 2.2, and 2.5 between 2007 and 2030. In terms of health impacts, by 2030, annual mean concentrations of fine particles (PM2.5) would increase to more than 150 μg/m3 in some parts of Punjab region of Pakistan, for which loss in statistical life expectancy is calculated to increase from 30 to 60 months in 2007 up to 60–100 months in 2030 on average. © 2016 Springer-Verlag Berlin Heidelberg
Ramzan M.,University of Tokyo |
Ham S.,Climate Center |
Amjad M.,Global Change Impact Studies Center |
Chang E.-C.,Kongju National University |
Yoshimura K.,University of Tokyo
Advances in Meteorology | Year: 2017
Sensitivity experiments testing two scale-selective bias correction (SSBC) methods have been carried out to identify an optimal spectral nudging scheme for historical dynamically downscaled simulations of South Asia, using the coordinated regional climate downscaling experiment (CORDEX) protocol and the regional spectral model (RSM). Two time periods were selected under the category of short-term extreme summer and long-term decadal analysis. The new SSBC version applied nudging to full wind components, with an increased relaxation time in the lower model layers, incorporating a vertical weighted damping coefficient. An evaluation of the extraordinary weather conditions experienced in South Asia in the summer of 2005 confirmed the advantages of the new SSBC when modeling monsoon precipitation. Furthermore, the new SSBC scheme was found to predict precipitation and wind patterns more accurately than the older version in decadal analysis, which applies nudging only to the rotational wind field, with a constant strength at all heights. © 2017 Mehwish Ramzan et al.
Khan F.,Institute For Statistikalpen Adria University |
Pilz J.,Institute For Statistikalpen Adria University |
Ali S.,Global Change Impact Studies Center
Water and Environment Journal | Year: 2017
The availability of water resources plays an important role for the economy of a country. The nexus of energy-food-water are interlinked and of particular importance in the uncertain environment of developing countries. In Pakistan, agriculture contributes 25% to the gross domestic product. The Indus River contributes 44% of the available water to irrigation of crops and the ecosystem, and currently produces 5,112 MW electricity, with the potential to produce 38,602 MW electricity. This makes it important to investigate the status of water availability in the Upper Indus Basin under existing emission scenarios. In this study, the future availability of water is projected for the Indus River under the A2, B2, RCP4.5 and RCP8.5 emission scenarios. A meta-analysis has been conducted to present a combined picture by combining the results from the emission scenarios. Our meta-analysis shows higher confidence in RCPs projections. The results show that suffcient water will be available in the Indus River that will meet the demands of water in future but there will be scarcity of water in some months under each scenario. However, by proper management and optimum utilisation of the available water, this scarcity can be resolved. © 2017 CIWEM.
Yadav R.K.,Indian Institute of Tropical Meteorology |
Yoo J.H.,Abdus Salam International Center For Theoretical Physics |
Kucharski F.,Abdus Salam International Center For Theoretical Physics |
Abid M.A.,Global Change Impact Studies Center
Journal of Climate | Year: 2010
This study examines decadal changes of the El Niño-Southern Oscillation (ENSO) influence on the interannual variability of northwest India winter precipitation (NWIWP). The analysis is based on correlations and regressions performed using India Meteorological Department (IMD) records based on station data and reanalysis fields from 1950 to 2008. The authors find that the interannual variability of NWIWP is influenced by the ENSO phenomenon in the recent decades. This conclusion is supported by a consistency across the different observational datasets employed in this study and confirmed by numerical modeling. A physical mechanism for such an influence is proposed, by which western disturbances (WDs) are intensified over northwest India because of a baroclinic response due to Sverdrup balance related to large-scale sinking motion over the western Pacific during the warm phase of ENSO. This response causes an upper-level cyclonic circulation anomaly north of India and a low-level anticyclonic anomaly over southern and central India. The cyclonic circulation anomaly intensifies the WDs passing over northwest India. © 2010 American Meteorological Society.
Zhu T.,International Food Policy Research Institute |
Ringler C.,International Food Policy Research Institute |
Iqbal M.M.,Global Change Impact Studies Center |
Sulser T.B.,Food and Agriculture Organization of the United Nations |
Goheer M.A.,Global Change Impact Studies Center
Water International | Year: 2013
Climate change is expected to considerably affect the water resources in the Indus River basin in Pakistan and thus agricultural production in the country. This article reports an analysis of the impacts of various climate scenarios on both water resources and food production out to 2050. While changes in water availability range from -12% to +24%, depending on the scenario, crop yield and production impacts are negative across all scenarios, and net food imports increase. We suggest a combination of accelerated investment in agricultural research and increased water-use efficiency in agriculture to reduce the adverse impacts of climate change on water and food. © 2013 International Water Resources Association.
Ali S.,Chinese Academy of Sciences |
Ali S.,Global Change Impact Studies Center |
Li D.,Chinese Academy of Sciences |
Congbin F.,Chinese Academy of Sciences |
Khan F.,Klagenfurt University
Environmental Research Letters | Year: 2015
This study is based on both the recent and the predicted twenty first century climatic and hydrological changes over the mountainous Upper Indus Basin (UIB), which are influenced by snow and glacier melting. Conformal-Cubic Atmospheric Model (CCAM) data for the periods 1976-2005, 2006-2035, 2041-2070, and 2071-2100 with RCP4.5 and RCP8.5; and Regional Climate Model (RegCM) data for the periods of 2041-2050 and 2071-2080 with RCP8.5 are used for climatic projection and, after bias correction, the same data are used as an input to the University of British Columbia (UBC) hydrological model for river flow projections. The projections of all of the future periods were compared with the results of 1976-2005 and with each other. Projections of future changes show a consistent increase in air temperature and precipitation. However, temperature and precipitation increase is relatively slow during 2071-2100 in contrast with 2041-2070. Northern parts are more likely to experience an increase in precipitation and temperature in comparison to the southern parts. A higher increase in temperature is projected during spring and winter over southern parts and during summer over northern parts. Moreover, the increase in minimum temperature is larger in both scenarios for all future periods. Future river flow is projected by both models to increase in the twenty first century (CCAM and RegCM) in both scenarios. However, the rate of increase is larger during the first half while it is relatively small in the second half of the twenty first century in RCP4.5. The possible reason for high river flow during the first half of the twenty first century is the large increase in temperature, which may cause faster melting of snow, while in the last half of the century there is a decreasing trend in river flow, precipitation, and temperature (2071-2100) in comparison to 2041-2070 for RCP4.5. Generally, for all future periods, the percentage of increased river flow is larger in winter than in summer, while quantitatively large river flow was projected, particularly during the summer monsoon. Due to high river flow and increase in precipitation in UIB, water availability is likely to be increased in the twenty first century and this may sustain water demands. © 2015 IOP Publishing Ltd.
Amjad M.,Global Change Impact Studies Center |
Zafar Q.,Global Change Impact Studies Center |
Khan F.,Global Change Impact Studies Center |
Sheikh M.M.,Global Change Impact Studies Center
International Journal of Climatology | Year: 2015
Weather research and forecasting (WRF) model is the state-of-the-art mesoscale model that could be used as a guideline to effectively assess the wind resource of Gharo wind station lying in the coastal belt of Pakistan. The anemometer heights of 10 and 30 m for the year 2005 have been used to study the wind profile of the region for summer (June, July, August, September) and winter (December, January, February, March). The study uses an innovative approach for model comparisons, i.e. an eta-half level is added in the model on 60 m height and is interpolated to 30 m height by using well known power law. This is done by studying the diurnal variation of wind shear for the whole year of 2005 in order to reduce maximum possible interpolation error. For both seasons, the error measures of mean bias error (MBE), mean absolute error (MAE) and root mean square error (RMSE) of 30 m interpolated data were found lower than 10 m height data with increased correlation (r). A bias correction methodology (best easy systematic estimator) was further applied over the model output showing a significant improvement toward MBE, MAE and RMSE reduction, i.e. up to 99%, 73% and 68% on 10 m height and 99%, 51% and 46% on 30 m height. Errors were reduced more for summer than winter. The selected bias correction methodology was thus found to be highly applicable for both model heights. The wind energy assessment of Gharo wind station from the corrected model simulation showed summer having more potential for wind energy than winter with an estimated energy of up to 1000 MWh. © 2015 Royal Meteorological Society.