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Moisture Transport over the Arabian Sea Associated with Summer Rainfall over Pakistan in 1994 and 2002

Advances in Atmospheric Sciences 2012年第3期29卷 501-508页

作者： kalim ullah 高守亭 Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Graduate University of the Chinese Academy of Sciences Department of Meteorology COMSATS Institute of Information TechnologyIslamabadPakistan

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 con- ducted; 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 Pak- istan 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.

关键词： moisture flux moisture convergence convection heavy rainfall

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Characterization of Drought and Its Assessment over Sindh,Pakistan During 1951-2010

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Journal of Meteorological Research 2015年第5期29卷 837-857页

作者： Shahzada ADNAN kalim ullah 高守亭 Department of Meteorology COMSATS Institute of Information Technology(CIIT) National Drought Monitoring Centre Pakistan Meteorological Department Institute of Atmospheric Physics Chinese Academy of Sciences State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences

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 （July- September）, 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 vulnerabilitv of drought and its seasonal predictability in Pakistan.

关键词： climatology drought standardized precipitation index (SPI) regional drought identification model (ReDIM) Sindh

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Meteorological impacts on evapotranspiration in different climatic zones of Pakistan

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Journal of Arid Land 2017年第6期9卷 938-952页

作者： Shahzada ADNAN kalim ullah Azmat H KHAN GAO Shouting Department of Meteorology COMSATS Institute of Information Technology Islamabad 44000 Pakistan Pakistan Meteorological Department Islamabad 44000 Pakistan State key Laboratory of Cloud-Precipitation Physics and SevereStorms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

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.

关键词： evapotranspiration meteorological parameters climatic zone Penman Monteith method Pakistan

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Impact of temperature on yield and related traits in cotton genotypes

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Journal of Integrative Agriculture 2016年第3期15卷 678-683页

作者： kalim ullah Niamatullah Khan Zahid Usman Rehmat ullah Fazal Yazdan Saleem Syed Asif Imran Shah Muhammad Salman Pakistan Central Cotton Committee Cotton Research Station Department of Agricultural Extension Education & Communication The University of Agriculture Oil Seed Programme National Agriculture Research Center

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.

关键词： Gossypium hirsutum planting dates growing degree days genotypes

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Precise Seismic Substructural Model of the Eocene Chorgali Limestone in the Turkwal Oil Field, Central Potwar, Pakistan

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Acta Geologica Sinica(English Edition) 2019年第6期93卷 1711-1720页

作者： Khawar Ashfaq AHMED Sarfraz KHAN Mahmood SULTAN UMAIR Bin Nisar kalim ullah Al-Hseinat MU’AYYAD Comsats University Islamabad(CUI)Pakistan National Centre of Excellence in Geology University of PeshawarPeshawar25130KPPakistan Centre for Earthquake Studies National Centre for Physics(NCP)IslamabadPakistan Centre for Climate Research and Development(CCRD) CUIIslamabadPakistan Department of Geology University of JordonAmmanJordan

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.

关键词： 2D seismic well correlation fore-thrust structural traps AVO model Eocene Chorgali Limestone and Basement Potwar

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Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus(Diptera:Culicidae)

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Asian Pacific Journal of Tropical Biomedicine 2016年第6期6卷 485-491页

作者： Gul Zamin Khan Inamullah Khan Imtiaz Ali Khan Alamzeb Muhammad Salman kalim ullah Entomology Division Nuclear Institute for Food and Agriculture (NIFA) Department of Entomology Faculty of Crop Protection Sciencesthe University of Agriculture Pakistan Central Cotton Committee Cotton Research Station

Objective: To test the relative efficacy of pyriproxyfen and methoprene on mortality,deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes ***: 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 *** 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 ***: 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 ***: 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.

关键词： Insect growth regulators Mortality Inhibition Deformities Insecticides Environment friendly

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Determinants of corporate cash holdings in tranquil and turbulent period:evidence from an emerging economy

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Financial Innovation 2019年第1期5卷 42-53页

作者： Khalil Jebran Amjad Iqbal kalim ullah Bhat Muhammad Arif Khan Mustansar Hayat School of Accounting Dongbei University of Finance and EconomicsDalianChina School of Management Fudan UniversityShanghaiChina Faculty of Management and Economics Dalian University of TechnologyDalianChina

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 *** divide the sample into three sub-periods—pre-crisis,crisis,and post-crisis—and apply a panel data model to estimate the *** results suggest that financial crises affect firms’cash holdings ***,findings show that financial crisis has influenced the relationship of size and leverage with cash *** particular,cash flow,liquidity,and tangibility are major determinants of cash holdings in the *** present important implications for corporate managers,academicians,and policymakers.

关键词： Cash holdings Financial crisis Pakistan Emerging economy

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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

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大气科学 2021年第1期45卷 148-164页

作者：黄昕周玉淑冉令坤 kalim ullah 曾勇中国科学院大气物理研究所云降水物理与强风暴院重点实验室北京100029 中国科学院大学北京100049 中国气象局乌鲁木齐沙漠气象研究所乌鲁木齐830002 Department of Meteorology COMSATS Institute of Information TechnologyPakistan 44000

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... 详细信息

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。

关键词：新疆伊犁河谷不稳定位势散度

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面向火星应用的MEMS热风传感器的仿真设计

面向火星应用的MEMS热风传感器的仿真设计

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作者： kalim ullah 东南大学

学位级别：硕士

本文对面向火星应用的热风传感器进行了建模和仿真,论文主要研究了火星环境对于风速传感器性能的影响。通过使用COMSOL Multiphysics对粉尘的影响和两个热敏电阻之间的温差进行建模。其中2个热风速度传感器是由基于硅衬底的4个温度传感... 详细信息

本文对面向火星应用的热风传感器进行了建模和仿真,论文主要研究了火星环境对于风速传感器性能的影响。通过使用COMSOL Multiphysics对粉尘的影响和两个热敏电阻之间的温差进行建模。其中2个热风速度传感器是由基于硅衬底的4个温度传感器(铂)围绕的加热器组成,后表面感应用来保护风速传感器。由于MARS环境恶劣,对三种不同情况进行了研究。与地球相比,火星星球的平均气温和大气压力非常低。相比之下,风速和温度分布均高于地球。在平均温度(250K),低温(187K)和高温(293K)下平均压力(800Pa)进行模拟。对于平均表面温度和1Om/s风速,上游和下游温度传感器之间的温差为0.183K,随风速而增加。在较低温度(187K)时,温差升高至0.221K。另一方面,高温下的温差降至 0.161K。第一种情况,假设灰尘在流动通道(CO2)中。流动通道中的粉尘浓度为5%至20%。因此,通过计算等效热导率并考虑了空气导热系数的变化,在5%粉尘浓度下,从上游到下游的温差从0.07K增加到0.14K。温差随着粉尘浓度增加到10%,15%和20%。第二种情况,灰尘落在硅衬底表面,等效于一个灰尘层,并将其厚度从10μm逐渐增加到30μm。使用平均风速/速度(10m/s～80m/s)观测上游和下游之间的温差。上游到下游的总体温差与0.141K相比下降到0.0936K,同时随着衬底表面灰尘层厚度的增加而减小。第三种情况是第一和第二种情况的组合。粉尘落在硅衬底的表面上,并且还考虑了流动通道(C02)。和第一种情况一样,在流量通道(C02)中形成的粉尘浓度为5%至20%,同时假定相同的热导率,灰尘层厚度按照第二种情况从10μm逐渐增加到30μm。对于每种灰尘厚度,施加平均风速(10m/s～80m/s),等效热导率从5%变化到20%。在10m/s的风速和10μm的灰尘厚度下,总体温差下降了 0.140K。此外,该温差随着硅衬底表面上的灰尘厚度的增加而减小。与地球环境中的温差相比,火星环境中的整体温差有所提高。这种现象源于星球的低密度、低气压、低平均温度和灰尘环境。

关键词：热风速传感器粉尘效应热分布火星

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Model Farm Services Center Approach: An Implication to Boost Farmer’s Yield

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Agricultural Sciences 2015年第9期6卷 953-960页

作者： Rehmat ullah Muhammad Zafarullah Khan kalim ullah Tahir Munir Butt Department of Agricultural Extension Education and Communication The University of Agriculture Peshawar Pakistan Pakistan Central Cotton Committee Cotton Research Station Dera Ismail Khan Pakistan College of Humanities and Development Studies China Agriculture University Beijing China

The instant study was conducted to estimate the Model Farm Services Center’s (MFSC) contribution in yield improvement of major crops/vegetables in district Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan, during the year 2014-15. Based on Sekaran sampling technique 306 respondents were selected and were personally interviewed through well prepared and pre-tested interview schedule. To find out the actual performance of yield improvement by Model Farm Services Center along with other repressors, step by step analysis was performed. The results of Wilcoxon Sign Rank Test showed significant improvement in yield of sugarcane, wheat, maize, rice and tomato by Model Farm Services Center. Pearson’s correlation coefficient showed highly significant positive relation of sugarcane and wheat yield difference before and after Model Farm Services Center registration with MFSC. Ordinary Least Square Multiple-Regression Model indicates that MFSC registration duration and landholding significantly define the variation in dependent variables at 1% and 5% level of significance respectively for sugarcane yield. Whereas solely Model Farm Services Center registration duration profoundly highly significantly (P ≤ 0.01) explains the variation in dependent variables in wheat yield.

关键词： Model Farm Services Center Sugarcane Wheat Pakistan

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