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1.
Natural Hazards - Extreme weather events such as heat waves and cold spells affect people’s lives. This study develops a probabilistic framework to evaluate heat waves and cold spells. As... 相似文献
2.
Elham Shafieiyoun Mahdi Gheysari Mehdi Khiadani Jahangir Abedi Koupai Paria Shojaei Mohammad Moomkesh 《水文研究》2020,34(20):4000-4016
Estimation of reference evapotranspiration (ET0) in urban areas is challenging but essential in arid urban climates. To evaluate ET0 in an urban environment and non-urban areas, air temperature and relative humidity were measured at five different sites across the arid city of Isfahan, Iran, over 4 years. Wind speed and sunshine hours were obtained from an urban surrounding weather station over the same period and used to estimate ET0. Calculated ET0 was compared with satellite-based ET0 retrieved from the MOD16A2 PET product. Although MODIS PET was strongly correlated with the Valiantzas equation, it overestimated ET0 and showed average accuracy (r = 0.93–0.94, RMSE = 1.18–1.28 mm/day, MBE = 0.73–0.84 mm/day). The highest ET0 differences between an urban green space and a non-urban area were 1.1 and 0.87 mm/day, which were estimated by ground measurements and MODIS PET, respectively. The sensitivity of ET0 to wind speed and sunshine hours indicated a significant effect on cumulative ET0 at urban sites compared to the non-urban site, which has a considerable impact on the amount of irrigation required in those areas. Although MODIS PET requires improvement to accurately reflect field level microclimate conditions affecting ET0, it is beneficial to hydrological applications and water resource managers especially in areas where data is limited. In addition, our results indicated that using limited data methods or meteorological data from regional weather stations, leads to incorrect estimation of ET0 in urban areas. Therefore, decision-makers and urban planners should consider the importance of precisely estimating ET0 to optimize management of urban green space irrigation, especially in arid and semi-arid climates such as the city of Isfahan. 相似文献
3.
Ashrafun Nahar Jeff Luckstead Eric J. Wailes Mohammad Jahangir Alam 《Climatic change》2018,150(3-4):289-304
Bangladesh, the sixth largest rice producer in the world, has been identified as high risk from the effects of climate change. Many of the adverse impacts of climate change such as land inundation and changes in weather patterns and CO2 levels will impact the agricultural sector. This study develops a partial-equilibrium multi-regional farm household model of Bangladesh rice and non-rice agricultural markets to quantify the impacts of climate change on consumption, production, prices, and farmers’ welfare. The model is calibrated to the Bangladesh rice market using Household Income and Expenditure Survey data. The model is simulated to analyze the impact of land reduction and productivity decline resulting from climate change. The results show that the decline in production in the coastal and northern regions offsets the production increase in the central and eastern regions, and the simulation predicts that total rice production for Bangladesh falls by about 2%. As total rice consumption falls and imports rise, the net effect leads to a rise in the rice price by 5.71% and a decline in farmers’ welfare. Sensitivity analysis shows that more- (less-) effective abatement technology could play a key role in mitigating (exacerbating) the price and welfare effects. The model predicts that many farmers in regions directly impacted by climate change could leave farming in search of off-farm work. Thus, the government can ease this transition by promoting urban development to provide more job options and technical training for farmers. 相似文献
4.
Haris Ahmed KHAN Ali Asghar SHAHID Muhammad Jahangir KHAN Taher ZOUAGHI Maria Dolores ALVAREZ Syed Danial Mehdi NAQVI 《《地质学报》英文版》2023,97(1):256-268
This research is focused on the analysis of the sequence stratigraphic units of F3 Block, within a wave-dominated delta of Plio–Pleistocene age. Three wells of F3 block and a 3D seismic data, are utilized in this research. The conventional techniques of 3D seismic interpretation were utilized to mark the 11 surfaces on the seismic section. Integration of seismic sequence stratigraphic interpretation, using well logs, and subsequent 3D geostatistical modeling, using seismic data, aided to evaluat... 相似文献
5.
Shah Ashfaq Ahmad Wu Wenya Gong Zaiwu Pal Indrajit Khan Jahangir 《Natural Hazards》2021,105(2):1977-2005
Natural Hazards - Children spend more than two-thirds of their total daytime in schools and becoming more persuasive in shielding them from potential hazards. Schools have a responsibility to... 相似文献
6.
Sanzidur Rahman Ismat Ara Begum Mohammad Jahangir Alam 《Singapore journal of tropical geography》2012,33(2):241-254
This paper re‐examines the effect of green revolution (GR) diffusion on factor/inputs demand in Bangladesh using an empirical model that allows for simultaneous determination of factors influencing adoption of GR technology at the current mature stage, as well as access to irrigation. Results reveal some alignments with conventional wisdom as well as few surprises. For example, while an increased demand for major inputs is expected, an increased demand for organic manure is an unexpected positive outcome. The GR adoption rate is significantly higher in villages with access to irrigation and fertile soils and, surprisingly, in infrastructurally underdeveloped villages. Together with other expected findings of GR technology uptake with higher cereal prices and irrigation use encouraged by access to credit, tenurial status and fertile soils, our findings suggest that investment in irrigation and soil conservation, as well as implementing measures to improve cereal prices and provide agricultural credit, could boost GR technology adoption. 相似文献
7.
Water and sediment quality, partial mass budget and effluent N loading in coastal brackishwater shrimp farms in Bangladesh 总被引：2，自引：0，他引：2
Shahidul Islam M Jahangir Sarker M Yamamoto T Abdul Wahab M Tanaka M 《Marine pollution bulletin》2004,48(5-6):471-485
The present study aimed to quantify the water and sediment quality and growth and production parameters and to establish nutrient budgets for an average of five selected semi-intensive shrimp ponds in Bangladesh over a growing cycle. Physico-chemical parameters of water and sediments were measured and analyzed by standard methods. Gross yield (kg ha-1) of shrimp was calculated from the stocking and harvesting data. Finally, a partial nutrient mass budget for N and P was calculated. Most of the parameters of water and sediments correlated significantly with each other suggesting a high degree of interactions between different parameters in the system. Significantly higher concentrations of all species of nitrogenous nutrients were recorded in the effluent waters than that entering into the ponds. Therefore, a high loading and net output of nitrogenous nutrients in effluent waters was documented. The study also indicated a net discharge of solids and minerals through effluent loading. However, significantly lower concentrations of phosphorus in the effluent water indicated a net retention and trapping of phosphatic nutrients in the environment. Total production ranged between 532.0 and 697.0 kg ha-1 cycle-1 and P. monodon production between 484.0 and 562.0 kg ha-1 cycle-1. Ponds gained nitrogen primarily from intake water (55%) and fertilizers (29%), and nitrogen was lost primarily from water exchange (78%) and harvested shrimp (12%). Phosphorus gain occurred mostly from intake water (52%) and fertilizers (25%), and phosphorus was lost primarily from water exchange (52%) and harvested shrimp (3.3%). About 10% of input nitrogen and 44% of phosphorus were not accounted for in measured losses, and presumably were fixed or metabolized in the system. On average, 78 g N was discharged to and 25 g P was removed from the surrounding water by the system for each kilogram of shrimp produced. Mean conversion of feed nitrogen and phosphorus to shrimp flesh averaged 74% and 40%, respectively. It was concluded that semi-intensive systems serve as net supplier of N to and net remover of P from the surrounding water. 相似文献
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9.
Samira Akhavan Sayed-Farhad Mousavi Jahangir Abedi-Koupai Karim C. Abbaspour 《Environmental Earth Sciences》2011,63(6):1155-1167
One of the major causes of groundwater pollution in Hamadan–Bahar aquifer in western Iran is a non-point source pollution
resulting from agricultural activities. Withdrawal of over 88% of drinking water from groundwater resources, adds urgency
to the studies leading to a better management of water supplies in this region. In this study, the DRASTIC model was used
to construct groundwater vulnerability maps based on the “intrinsic” (natural conditions) and “specific” (including management)
concepts. As DRASTIC has drawbacks to simulate specific contaminants, we conditioned the rates on measured nitrate data and
optimized the weights of the specific model to obtain a nitrate vulnerability map for the region. The performance of the conditioned
DRASTIC model improved significantly (R
2 = 0.52) over the intrinsic (R
2 = 0.12) and specific (R
2 = 0.19) models in predicting the groundwater nitrate concentration. Our study suggests that a locally conditioned DRASTIC
model is an effective tool for predicting the region’s vulnerability to nitrate pollution. In addition, comparison of groundwater
tables between two periods 30 years apart indicated a drawdown of around 50 m in the central plain of the Hamadan–Bahar region.
Our interpretation of the vulnerability maps for the two periods showed a polluted zone developing in the central valley requiring
careful evaluation and monitoring. 相似文献
10.
Md. Jahangir Alam Yuan Daoxian Yong Jun Jiang Sun Yuchuan Li Yong Xu Xin 《Environmental Earth Sciences》2014,71(4):1977-1987
Karst areas have much higher ecological vulnerability and are prone to be contaminated. Organochlorine pesticides (OCPs) were detected in waters and sediment from the two sites of the karst Nanshan underground river system, China, to understand the sources and transport of OCPs in the underground river systems. Obviously, seasonal variations were found both in the waters and the sediments. Detected OCPs ranged from 61 to 936 ng L?1 in the groundwaters and 51–3,842.0 ng g?1 in the underground sediments, respectively. OCPs in groundwaters were mixture of younger and older residues from commercial sources. The maximum OCPs in the sediments of the underground river were historically older residues from commercial sources. The sources of OCPs in the waters and sediments of the underground river indicated that the surface systems play an important role in OCPs transport and pollution in the underground river. Karst features were liable for the transport behavior. 相似文献