Climate change and human activities: a case study in Xinjiang, China

We examined both long-term climate variability and anthropogenic contributions to current climate change for Xinjiang province of northwest China. Xinjiang encompasses several mountain ranges and inter-mountain basins and is comprised of a northern semiarid region and a more arid southern region. Climate over the last three centuries was reconstructed from tree rings and temperature series were calculated for the past 50 years using weather station data. Three major conclusions from these analyses are: (1) Although temperature varied considerably in Xinjiang over the last 200 years, it was non-directional until the last 50 years when a substantial warming trend occurred; (2) The semiarid North Xinjiang was representative of the northern hemisphere climate, while the more arid South Xinjiang resembled the southern hemisphere climate, meanwhile, (3) The entire Xinjiang province captured the global-scale climate signal. We also compared human contributions to global change between North and South Xinjiang, including land cover/land use, population, and greenhouse gas production. For both regions, urban areas acted as heat islands; and large areas of grassland and forest were converted to barren land, especially in North Xinjiang. Additionally, North Xinjiang also showed larger increase in population and greenhouse gas emissions mainly associated with animal production than those in South Xinjiang. Although Xinjiang province is a geographically coupled mountain–basin system, the two regions have distinct climate patterns and anthropogenic activities related to land cover conversion and greenhouse gas production.     

辽宁雾预报区的划分初探

分析了1997—2006年辽宁境内能见度小于1000 m雾的时空分布特征。结果表明：就雾发生的频率而言,辽宁存在两个高值区和两个低值区,高值区分别位于黄海北部沿岸至辽宁东部山区和锦州北部至阜新一带,低值区分别位于辽宁中北部平原以及朝阳地区。从雾的日变化上看,近86%的雾出现在夜间,近69%的雾出现在02-08时,且多为辐射雾。地域不同但气候条件相近时,雾的日变化与雾发生的次数存在极其相似的特点。依据相似的地理环境和气候条件、雾的日变化特征以及雾发生次数等,将辽宁划分为5个预报区,对雾采取分区预报,以提高雾预报的准确率。     

普通黑光灯对稻纵卷叶螟和稻飞虱的诱虫量与气象因子的相关分析

以1991年至2008年广东省恩平市的观测数据,分析了普通黑光灯对稻纵卷叶螟和稻飞虱诱虫量与气象条件的相关性.结果表明:稻纵卷叶螟蛾年总诱量与年总降雨量呈正相关,稻飞虱成虫年诱量与年降雨量呈负相关,稻纵卷叶螟蛾与主要为害的5、6、8月降雨均呈正相关,与7月降雨则呈负相关;稻飞虱与5、7、8月降雨均为负相关,与6月降雨为正相关.此外,热带气旋个数与稻飞虱年诱虫量呈负相关;与稻纵卷叶螟蛾年诱虫量呈正相关.综合分析表明,稻纵卷叶螟蛾与稻飞虱与气象因子比较有较大的差别,对普通黑光灯诱虫量有极大的影响,可间接预测预报两迁飞性害虫的发生量,为准确预测预报两迁害虫为害提供参考.     

华南区域季节性降水的差异分析

运用EOF方法研究华南区域降水时空分布特征,结果表明：（1）华南地区各季节降水在年际和年代际的时间变化上有区域一致性,但有季节性差异,其中春季和秋季在20世纪80年代后降水明显减少,旱年增多;而夏季90年代后降水明显增加,涝年增多;冬季变化则不明显。（2）华南地区各季节降水在空间分布上也有差异,其中春季降水呈现东多西少的分布特征,大值中心位于广西东北部、广东中部及西南沿海。夏季和秋季降水相似,呈南多北少的分布特征,大值中心位于广西沿海和广东西南沿海。冬季降水呈东北多西南少的分布特征,大值中心位于粤北。     

东北地区初霜冻的天气气候特征

利用实测资料和历史天气图资料,对近３１年我国东北地区初霜冻的天气气候特征进行了分析,并探讨了初霜冻出现前２４小时的环流形势特征和天气演变过程,给出了初霜冻的时空分布特征以及对预报有用的一些判据。对实时预报业务有参考作用。     

A possible explanation for the electron/positron excess of ATIC/PAMELA

Results from PAMELA and ATIC indicate that the Kaluza-Klein type dark matter particles could be the annihilation source of the observed excess of electrons and positrons.Assuming the existence of a nearby black hole with 10000–100000 solar masses and a point source boost algorithm,we apply the standard propagation model and find that the results fit the data well.     

RESPONSE OF EQUATORIAL PACIFIC UPPER OCEAN CURRENT TO WESTERLY WIND BURSTS

The characteristics of the response of equatorial Pacific upper ocean current to westerly wind bursts(WWB)were analyzed in the frequency domain by using wind and ADCP data collected by the Shiyan3 during TOGA-COARE IOP,1992-1993.The preliminary results showed that the response consistedof an eastward surface jet at shallower than 60m depth,a westward counter current centering near100m and a shear layer between them,with the variations of all three being nonlinear and nearlysynchronous.The oceanic responses in the frequency domain were characterized by occurrences of a remotely forced mixed Rossby-gravity wave with period of 8-10 days in the surface jet andcountercurrent at shallower than 110 m depth,and two locally forced waves with periods of 24 daysand 4-5 days limited in shallower than 70m depth.These fluctuations of the responses depended much more on zonal wind than meridional wind.The results also revealed that the oceanic response toWWB resulted from momentum transport and energy propagation assoc     

基于DDS技术的航空重力仪电容测微正弦激励源设计

介绍基于直接数字合成技术(DDS)研制的正弦激励源系统工作原理,运用matlab-simulink仿真模块仿真正弦激励源数据,结果表明,幅值稳定性可达到10-6~10-7,频率稳定性达到10-4,该系统能解决以往正弦电路中幅值稳定度和高频时频率稳定度差的问题,提高航空重力仪的观测精度。