Hydrologic implications of the isotopic kinetic fractionation of open-water evaporation

The kinetic fractionation of open-water evaporation against the stable water isotope H_2 ~(18)O is an important mechanism underlying many hydrologic studies that use ~(18)O as an isotopic tracer. A recent in-situ measurement of the isotopic water vapor flux over a lake indicates that the kinetic effect is much weaker(kinetic factor 6.2‰) than assumed previously(kinetic factor14.2‰) by lake isotopic budget studies. This study investigates the implications of the weak kinetic effect for studies of deuterium excess-humidity relationships, regional moisture recycling, and global evapotranspiration partitioning. The results indicate that the low kinetic factor is consistent with the deuterium excess-humidity relationships observed over open oceans.The moisture recycling rate in the Great Lakes region derived from the isotopic tracer method with the low kinetic factor is a much better agreement with those from atmospheric modeling studies than if the default kinetic factor of 14.2‰ is used. The ratio of transpiration to evapotranspiration at global scale decreases from 84±9%(with the default kinetic factor) to 76±19%(with the low kinetic factor), the latter of which is in slightly better agreement with other non-isotopic partitioning results.     

中蒙强、弱沙尘暴年春季平均环流及沙尘活动变化分析

利用NCEP/NCAR再分析资料,对比分析了中蒙东、中及西区强、弱沙尘暴年春季(3-5月)平均环流的特征和差异,讨论了过去50年3分区沙尘暴活动的变化.主要结论是:(1)根据诱发沙尘暴的诱生系统、沙尘源地、冷空气入侵路径及主要影响,中蒙沙尘暴活动区可以划分为中蒙东区、中区及西区3个区系,并分区整体讨论与预测中蒙3分区的沙尘活动.(2)中蒙东区沙尘暴强年春季盛行日本海或中国东北低压活动,常随偏东的北路及东北路冷空气入侵,带来蒙古国东部的沙尘,造成蒙古东部及中国华北的沙尘天气;而弱年春季日本海及东北低压活动则少.(3)中蒙中区沙尘暴强年春季盛行蒙古低压,多西北路及偏西的北路冷空气入侵,常造成中蒙南边界西段附近的沙尘暴天气;而沙尘暴弱年春季则相反.(4)中蒙西区沙尘暴强年春季盛行南疆热低压,多西路冷空气入侵,诱发沙尘暴,常影响南疆及柴达木盆地等;弱年春季则相反.(5)近50年中蒙地区的沙尘暴活动呈波动变化,荒漠化环境、特别是大气环流的变化是导致上述3个分区沙尘活动波动变化的主要原因.主要从大气环流角度考虑,在目前全球增暖持续的背景下,近1-2年应注意中、东区(特别是东区)沙尘活动加强的可能性.     

基于期刊论文的中国地级以上城市知识专业化研究

将287个地级以上城市（不包括港澳台地区）作为研究对象,以中国知网发布的168个学科领域期刊论文数量为数据来源,对中国地级以上城市知识专业化水平、影响因素及其与经济发展的关系进行了研究。研究发现：① 中国地级以上城市的专业化水平总体偏低,多样化水平较为明显;知识专业化水平西部地区>中部地区>东部地区;地区相对专业化指数随城市行政等级依次升高,即直辖市<副省级城市<省会城市<普通地级市。具有资源优势的城市,其知识专业化领域高度集中在以资源为基础的领域;中小城市的知识专业化领域相对较少,专业化程度高;大中城市知识专业化领域多,多样化趋势明显,但各领域的知识专业化程度相对较低。从城市等级上来看,知识专业化程度表现为五线城市>四线城市>三线城市>二线城市>一线城市。② 知识专业化水平主要受科教经济因素、人才潜力和服务业因素、工业基础因素、人口规模因素四大因素影响。③ 知识专业化与经济发展关系密切,整体呈现倒U形关系;但各区域随发展阶段不同,表现出不同的形式可以分为U形、倒U形、M形和W形4种大类型。     

Understanding Agriculture Production and Food Security in Ethiopia from the Perspective of China

Food security and sustainable agricultural development are the hot issues of scientific research, especially after the population affected by hunger surprisingly increased in 2016. Long-lasting and recurrent famines caused by natural disasters and wars have afflicted Ethiopia. Unlike Ethiopia, which is still struggling to achieve food self-sufficiency, China managed to quickly become food self-sufficient at a rapid speed, despite the fact that it also faced the same challenges of famine over the last century. In the backdrop of differing environmental and socio-political challenges the two countries face, comparing the similarities and differences between the two countries will yield important lessons and insights for Ethiopia to follow to achieve food self-sufficiency. Here, the progress towards food security in Ethiopia and China is presented to quantitatively compare the gap of agricultural production between both countries. We found that food production in Ethiopia is heavily constrained by drought, soil degradation, climate change, out-dated agricultural production technologies, and poverty. According to these challenges, we examined corresponding responses in China to propose solutions for achieving food self-sufficiency in Ethiopia, given the realities of its unique national situation.     

江苏省入太湖污染量分析(1998-2007年)

近年来,太湖水体受到了严重污染,水环境质量逐年下降,太湖水环境的状况直接影响了地区的经济和社会发展,保护太湖已列为国家重点治理项目。本文根据1998-2007年环太湖水文巡测资料及主要入湖河道水质监测成果,分析入湖水量、入湖河道水质、入湖污染物量及其变化趋势,为太湖地区水环境综合整治提供技术支撑和决策依据。     

GIS的语音功能实现

和大多数信息系统一样,地理信息系统(GIS)主要是通过键盘、鼠标和屏幕进行人机信息交流,人机交流方式的增加有可能拓展信息系统的应用空间。通过ArcEngine和Microsoft Speech SDK的结合,笔者建立了一个具有语音功能的校园GIS,实现了GIS语音信息的输入与输出。     

Biogas charging and dissipating process and its accumulation in the Sebei gasfield,Qaidam Basin,China

The Sebei gasfield is the largest biogas accumulation found in China and many reservoirs and seal rocks superposed on a syndepositional anticline in Quaternary. The biogas charging and dissipating process and its distribution have been a research focus for many years. The authors suggest a diffusing and accumulating model for the biogas, as they find that the shallower the gas producer, the more methane in the biogas, and the lighter stable carbon isotope composition of methane. Based on the diffusing model, diffused biogas is quantitatively estimated for each potential sandy reservoir in the gasfield, and the gas charging quantity for the sandy reservoir is also calculated by the diffused gas quantity plus gas reserve in-place. A ratio of diffusing quantity to charging quantity is postulated to describe biogas accumulating state in a sandy reservoir, if the ratio is less than 0.6, the reservoir forms a good gas-pool and high-production layer in the gasfield, which often occurs in the reservoirs deeper than 900 m; if the ratio is greater than 0.6, a few gas accumulated in the reservoir, which frequently exists in the reservoirs shallower than 900 m. Therefore, a biogas accumulation model is built up as lateral direct charging from gas source for the sands deeper than 900 m and indirect charging from lower gas-bearing sands by diffusion at depth shallower than 900 m. With this charging and diffusion quantitative model, the authors conducted re-evaluation on each wildcat in the central area of the Qaidam Basin, and found many commercial biogas layers.

     

临震异常判别的统计分析

本文运用统计分析对地震预报中的临震前兆的异常与误差关系进行了讨论,指出了目前所存在的问题,提出了相应的改进意见。作为方法尝试,还结合楚雄短水准、昌黎地电阻率的资料进行了探讨。     

Deformation measurement by single spherical near-field intensity measurement for large reflector antenna

This paper presents a new method to obtain the deformation distribution on the main reflector of an antenna only by measuring the electric intensity on a spheri...     

A GPU based single-pulse search pipeline(GSP)with database and its application to the Commensal Radio Astronomy FAST Survey(CRAFTS)

We developed a GPU based single-pulse search pipeline(GSP)with a candidate-archiving database.Largely based upon the infrastructure of the open source PulsaR Ex...