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| 1 | 一次新疆伊犁河谷特大暴雨过程的环境场及不稳定条件分析显示文摘伊犁河谷是新疆地区暴雨多发且暴雨强度最强的地区。本文以该地区的一次特大暴雨过程为例,利用观测资料以及WRF高分辨率数值模拟结果对该次暴雨过程的环流背景及不稳定条件进行了分析。结果表明:(1)此次降水过程发生在对流层高层南亚高压'双体型',中层中高纬度'两脊一槽'以及两个中亚低涡发展移动的环流形势下。在伊犁河谷特殊的向西开口的喇叭口地形作用下,中心位于哈萨克斯坦的中亚低涡导致伊犁河谷低层为偏西风,中心位于塔里木盆地的中亚低涡使得伊犁河谷中层为偏东风,导致伊犁河谷内中低层水平风的垂直切变增强;伊犁河谷内,地形及哈萨克斯坦中亚低涡环流的共同作用形成了低空辐合线,辐合线附近形成的辐合区正好与高空急流辐散区垂直叠加,引发河谷内的上升运动增强。低层西风将水汽输送进河谷,并在河谷内迎风坡附近堆积,上升运动增强后导致河谷内堆积的水汽得以抬升。(2)WRF模拟结果分析显示,散度分布、垂直风切变、水汽及热力层结分布等对降水产生均有重要贡献。通过对湿位涡垂直及水平分量的分析得出热力层结影响的对流不稳定对前期降水的产生有影响,同时,垂直风切变影响的对称不稳定对降水增强维持有重要作用。位势散度分析进一步指示出整个降水区低层的对流不稳定主要是由于位势散度的垂直切变部分造成,而位势散度的散度部分能加强河谷内小地形背风坡处的对流不稳定,说明整个降水演变过程中,动热力因子的相互作用共同影响了降水强度和落区。 | 黄昕 周玉淑 冉令坤 KALIM Ullah 曾勇 | 2021 | 大气科学2021，45，1： | 14 |
| 2 | Meteorological impacts on evapotranspiration in different climatic zones of Pakistan显示文摘Arid regions are highly vulnerable and sensitive to drought. The crops cultivated in arid zones are at high risk due to the high evapotranspiration and water demands. This study analyzed the changes in seasonal and annual evapotranspiration(ET) during 1951–2016 at 50 meteorological stations located in the extremely arid, arid, and semi-arid zones of Pakistan using the Penman Monteith(PM) method. The results show that ET is highly sensitive and positively correlated to temperature, solar radiation, and wind speed whereas vapor pressure is negatively correlated to ET. The study also identifies the relationship of ET with the meteorological parameters in different climatic zones of Pakistan. The significant trend analysis of precipitation and temperature(maximum and minimum) are conducted at 95% confidence level to determine the behaviors of these parameters in the extremely arid, arid, and semi-arid zones. The mean annual precipitation and annual mean maximum temperature significantly increased by 0.828 mm/a and 0.014℃/a in the arid and extremely arid zones, respectively. The annual mean minimum temperature increased by 0.017℃/a in the extremely arid zone and 0.019℃/a in the arid zone, whereas a significant decrease of 0.007℃/a was observed in the semi-arid zone. This study provides probabilistic future scenarios that would be helpful for policy-makers, agriculturists to plan effective irrigation measures towards the sustainable development in Pakistan. | Shahzada ADNAN Kalim ULLAH Azmat H KHAN GAO Shouting | 2017 | Journal of Arid Land2017，9，6： | 2 |
| 3 | Moisture Transport over the Arabian Sea Associated with Summer Rainfall over Pakistan in 1994 and 2002显示文摘In this study,we aimed to elucidate the critical role of moisture transport affecting monsoon activity in two contrasting summers over the Arabian Sea during the years 1994,a relatively wet year,and 2002,a relatively dry year.A comprehensive diagnostic evaluation and comparisons of the moisture fields were conducted;we focused on the precipitation and evaporation as well as the moisture transport and its divergence or convergence in the atmosphere.Monthly mean reanalysis data were obtained from the National Centers for Environmental Prediction(NCEP-I and-II).A detailed evaluation of the moisture budgets over Pakistan during these two years was made by calculating the latent energy flux at the surface(E P) from the divergence of the total moisture transport.Our results confirm the moisture supply over the Arabian Sea to be the major source of rainfall in Pakistan and neighboring regions.In 1994,Pakistan received more rainfall compared to 2002 during the summer monsoon.Moisture flow deepens and strengthens over Arabian Sea during the peak summer monsoon months of July and August.Our analysis shows that vertically integrated moisture transport flux have a significant role in supplying moisture to the convective centers over Pakistan and neighboring regions from the divergent regions of the Arabian Sea and the Bay of Bengal.Moreover,in 1994,a deeper vertically integrated moisture convergence progression occurred over Pakistan compared to that in 2002.Perhaps that deeper convergence resulted in a more intense moisture depression over Pakistan and also caused more rainfall in 1994 during the summer monsoon.Finally,from the water budget analysis,it has been surmised that the water budget was larger in 1994 than in 2002 during the summer monsoon. | Kalim ULLAH 高守亭 | 2012 | Advances in Atmospheric Sciences2012，29，3： | 2 |
| 4 | Characterization of Drought and Its Assessment over Sindh,Pakistan During 1951-2010显示文摘Drought is one of the complex meteorological disasters affecting water resources,agriculture,livestock,and socioeconomic patterns of a region.Although drought prediction is difficult,it can be monitored based on climatological information.In this study,we provide high spatiotemporal resolution drought climatology,using observational,gridded precipitation data(0.5°×0.5°) from the Global Precipitation Climatological Center and soil moisture data from the Climate Prediction Center for the 60-yr period 1951-2010.The standardized precipitation index(SPI) based on a fitted Gamma distribution and Run method has been calculated from the regional drought identification model(ReDIM) for 3,6,9,12,and 24 months.The results show strong temporal correlations among anomalies of precipitation,soil moisture,and SPI.Analysis of long-term precipitation data reveals that the drought vulnerability concentrates on monsoon season(JulySeptember),which contributes 72.4%and 82.1%of the annual precipitation in northern and southern Sindh,respectively.Annual and seasonal analyses show no significant changes in the observed precipitation.The category classification criteria are defined to monitor/forecast drought in the selected area.Further analysis identifies two longest episodes of drought,i.e.,1972-1974 and 2000-2002,while 1969,1974,1987,and 2002 are found to be the most severe historical drought years.A drought hazard map of Sindh was developed,in which 10 districts are recognized as highly vulnerable to drought.This study helps to explain the time,duration,intensity,and frequency of meteorological droughts over Sindh as well as its neighboring regions,and provides useful information to disaster management agencies and forecasters for assessing both the regional vulnerability of drought and its seasonal predictability in Pakistan. | Shahzada ADNAN Kalim ULLAH 高守亭 | 2015 | Journal of Meteorological Research2015，29，5： | 2 |
| 5 | Impact of temperature on yield and related traits in cotton genotypes显示文摘Cotton growth and development is influenced by various uncontrollable environmental conditions. Temperature variations in the field can be created by planting at different dates. The objective of the present study was to evaluate the effect of planting dates and thermal temperatures(growing degree days) on yield of 4 cotton genotypes, viz., CIM-598, CIM-599, CIM-602 and Ali Akbar-703. Plants were subjected to 6 planting dates during 2013 and 2014 in a trial conducted in randomized complete block design with four replications. For boll number, boll weight and seed cotton yield, cotton genotypes exhibited significant differences, CIM-599 produced the highest seed cotton yield of 2 062 kg ha^(–1) on account of maximum boll number and boll weight. The highest seed cotton yield was recorded in planting dates from 15 th April to 1st May whereas early and delayed planting reduced the yield due to less accumulation of heat units. Regression analysis revealed that increase of one unit(15 days) from early to optimum date(15th March to 15 th April) increased yield by 93.58 kg ha^(–1). Delay in planting also decreased the seed cotton yield with the same ratio. Thus it is concluded that cotton must be sown from 15 th April to 1st May to have good productivity in this kind of environment. | Kalim Ullah Niamatullah Khan Zahid Usman Rehmat Ullah Fazal Yazdan Saleem Syed Asif Imran Shah Muhammad Salman | 2016 | Journal of Integrative Agriculture2016，15，3： | 1 |
| 6 | Precise Seismic Substructural Model of the Eocene Chorgali Limestone in the Turkwal Oil Field, Central Potwar, Pakistan显示文摘The precise seismic substructural interpretation of the Turkwal oil field in the Central Potwar region of district Chakwal of Pakistan has been carried out. The research work was confined to the large fore-thrust that serves as an anticlinal structural trap through ten 2 D seismic lines. A precise seismic substructural model of the Eocene Chorgali Limestone with precise orientation of thrust and oblique slip faults shows the presence of a huge fracture, which made this deposit a good reservoir. The abrupt surface changes in dip azimuth for the Eocene Chorgali Limestone verifies the structural trends and also the presence of structural traps in the Turkwal field. The logs of three wells(Turkwal deep X-2, Turkwal-01 and Fimkassar-01) were analyzed for petrophysical studies, well synthetic results and generation of an Amplitude Versus Offset(AVO) model for the area. The AVO model of Turkwal deep X-2 shows abrupt changes in amplitude, which depicts the presence of hydrocarbon content. Well correlation technique was used to define the overall stratigraphic setting and the thickness of the reservoir formation in two wells, Turkwal-01 and Turkwal deep X-2. The Eocene Chorgali Limestone in Turkwal-01 is an upward thrusted anticlinal structure and because of the close position of both wells to the faulted anticlinal structure, its lesser thickness differs compared to Turkwal deep X-2. The overall results confirm that the Turkwal field is comparable to several similar thrust-bound oil-bearing structures in the Potwar basin. | Khawar Ashfaq AHMED Sarfraz KHAN Mahmood SULTAN UMAIR Bin Nisar Kalim ULLAH Al-Hseinat MU’AYYAD | 2019 | Acta Geologica Sinica(English Edition)2019，93，6： | 1 |
| 7 | Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus(Diptera:Culicidae)显示文摘Objective: To test the relative efficacy of pyriproxyfen and methoprene on mortality,deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes albopictus.Methods: Serial dilutions(0.01–0.05 mg/L) of methoprene, pyriproxyfen 0.5 water dispersible granules(WDG) and pyriproxyfen 1.0 WDG were used to assess mortality and inhibition of 3rd instar larvae of Aedes albopictus and Culex quinquefasciatus. Each concentration and control was replicated four times in completely randomized design.Data on larval mortality, growth inhibition, deformities and adult's emergence was recorded weekly. On the basis of best comparative performance, the efficacy of pyriproxyfen 1.0 WDG at 0.1 g/m3 was also tested in the field by collecting treated water samples monthly for 1–6 months after field application. Twenty five 3rd instar larvae of Aedes and Culex spp. of the same cohorts were used for bioassays and compared with larvae in control cups containing 1 L of untreated tap water.Results: Results revealed variations in fatality of different insect growth regulators(IGRs) to the 3rd instar larvae of Culex and Aedes mosquitoes. Among the IGRs, pyriproxyfen 1.0 WDG was found best that exhibited significantly high emergence inhibition against Culex and Aedes spp. Based on the results, the IGRs were classified in terms of the tested parameters in order of pyriproxyfen 1.0 WDG > pyriproxyfen 0.5WDG > methoprene. In case of field studies, pyriproxyfen 1.0 WDG, pool data of the entire target treated sites showed minimum adult emergence from water sampled of habitats treated with 0.1 g/m3 of pyriproxyfen 1.0 WDG.Conclusions: It is thus concluded that IGRs can be utilized as environment friendly control measures for Culex and Aedes spp. of mosquitoes on small and large scale. This will reduce the use of conventional insecticides by the public health authorities and help in reducing selection pressure of insecticides. | Gul Zamin Khan Inamullah Khan Imtiaz Ali Khan Alamzeb Muhammad Salman Kalim Ullah | 2016 | Asian Pacific Journal of Tropical Biomedicine2016，6，6： | 0 |
| 8 | Determinants of corporate cash holdings in tranquil and turbulent period:evidence from an emerging economy显示文摘Using a sample of 280 firms listed on the Pakistan Stock Exchange,we empirically investigate factors that determine corporate cash holdings in different periods from 2005 to 2014.We divide the sample into three sub-periods—pre-crisis,crisis,and post-crisis—and apply a panel data model to estimate the results.The results suggest that financial crises affect firms’cash holdings policies.Further,findings show that financial crisis has influenced the relationship of size and leverage with cash holdings.In particular,cash flow,liquidity,and tangibility are major determinants of cash holdings in the sub-periods.We present important implications for corporate managers,academicians,and policymakers. | Khalil Jebran Amjad Iqbal Kalim Ullah Bhat Muhammad Arif Khan Mustansar Hayat | 2019 | Financial Innovation2019，5，1： | 0 |
| 9 | Pakistani Women Entrepreneurs in Life Course Approach显示文摘Recently women entrepreneur literature in developed countries has been assessed through their life course approach due to the criticism on the absence of study from the perspective of structural pattern,in which the women are embedded through means of qualitative study.This reveals so many clarifications to the existence themes.Still the Pakistani entrepreneurial literature neglecting the women entrepreneur life course experiences due to social-cultural context of Pakistan.The present study focused on the ten Pakistani women entrepreneur from Islamabad and Peshawar region by the lens of life course approach through semistructured interview.The qualitative analysis of the life course approach among Pakistani women entrepreneur exposed some additional factor to life course approach and contrary findings as compared to the developed countries.The Pakistani women’s rich stories are affected through life course approach but the socialcultural context made it little worst means bringing into business with less flexible approach. | Hira Batool Kalim Ullah | 2018 | Proceedings of Business and Economic Studies2018，1，1： | 0 |
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