东南极中山站地区大地电磁测深研究

对中山站附近２个大地电磁测深点的数据处理结果表明，拉斯曼丘陵地区的岩石圈厚度为１４０ｋｍ，在地壳内２２ｋｍ处有一高导层     

压磁地应力雷电干扰形态及其排除

本文通过对山东省长清地震台２０多年地应力观测资料的总结，分析研究了雷电干扰的形态、机理、途径，进而采取了防雷措施，并取得了较好的效果。     

Altitude pattern of carbon stocks in desert grasslands of an arid land region

For estimating the altitude-distribution pattern of carbon stocks in desert grasslands and analyzing the possible mechanism for this distribution, a detailed study was performed through a series of field vegetation surveys and soil samplings from 90 vegetation plots and 45 soil profiles at 9 sites of the Hexi Corridor region, Northwestern China. Aboveground, belowground, and litter-fall biomass-carbon stocks ranged from 43 to 109, 23 to 64, and 5 to 20 g/m2, with mean values of 80.82,44.91, and 12.15 g/m2, respectively. Soil-carbon stocks varied between 2.88 and 3.98 kg/m2, with a mean value of 3.43 kg/m2 in the 0–100-cm soil layer. Both biomass-and soil-carbon stocks had an increasing tendency corresponding to the altitudinal gradient. A significantly negative correlation was found between soil-carbon stock and mean annual temperature, with further better correlations between soil-and biomass-carbon stocks, and mean annual precipitation. Furthermore, soil carbon was found to be positively correlated with soil-silt and-clay content, and negatively correlated with soil bulk density and the volume percent of gravel. It can be concluded that variations in soil texture and climate condition were the key factors influencing the altitudinal pattern of carbon stocks in this desert-grassland ecosystem. Thus, by using the linear-regression functions between altitude and carbon stocks, approximately 4.18 Tg carbon were predicted from the 1,260 km2 of desert grasslands in the study area.     

Biological improvement of saline alkali soil reference system: A review

This work presents a reference system overview to improve the efficiency of biological improvement of saline-alkali soil developed during the last thirty years, ranging from connotation, general methods and species, soil desalination, soil structure, soil organic content, microbial flora, enzyme activity, yield and economic benefits. The reference system presented is divided into three main groups: suitable varieties, suitable cultivation measures, and a comprehensive evaluation system.There has been a lot of research on biological improvement of saline alkali soil, but these studies are very fragmented and lack a comprehensive standard system. Also, there is a lack of practical significance, particularly with regard to optimal species, densities and times of sowing for particular regions. On the other hand, the corresponding cultivation measure is very important. Therefore, a reference system plays an important role to the effect of biological improvement of saline alkali soil.     

220ka BP来大同盆地常量元素记录的气候变化

大同盆地第四纪以来发育了厚层的河湖相,上覆马兰黄土或全新统,蕴含着丰富的过去气候变化信息。以地层测年数据建立年代框架,结合地层磁化率、粒度测试资料,主要以常量化学元素为气候代用指标,对气候变化进行分析。结果表明:(1)地层沉积物中常量化学元素含量的平均值SiO_2>Al_2O_3>CaO>Na_2O>Fe_2O_3>K_2O>MgO,沉积相不同元素含量存在明显差异,反映出元素聚集时气候环境存在差异。(2)220ka BP以来大同盆地气候变化经历了中更新世220~199ka BP暖湿期、中更新世199~138ka BP干燥寒冷期、末次间冰期138~71ka BP温暖湿润期、末次冰期71~11ka BP寒冷干燥期、全新世11ka BP至今的暖湿冷干交替频繁波动期,在每个时段仍存在次一级的气候波动。(3)这种气候变化过程与纬度位置大体相近的中国北方萨拉乌苏河流域、内蒙古岱海地区有着相似的气候变化过程,反映出本区气候变化是全球气候变化所导致的东亚冬夏季风势力互为消长的区域响应。     

青海东部地区雷电灾害易损性分析与区划

利用青海东部地区10个气象台站1997—2012年的年平均雷暴日数,2008—2014年闪电定位数据和1997—2014年雷电灾害资料,将雷暴日数、雷击密度、综合灾度、生命易损模数和经济易损模数作为雷电灾害易损性评估指标,采用层次分析法确定指标的权重,建立了雷电灾害易损性评估模型,依据气象灾害学分级统计法划分出雷电灾害易损性等级,形成了青海东部地区雷电灾害易损性区划图。结果表明青海东部地区雷电灾害易损性区域呈分散分布的特征,极高易损区在大通县、化隆县,次高易损区在湟中县、互助县,中易损区在省会城市西宁市、湟源县,低易损区在乐都区、平安区、民和县和循化县。     

Arctic multiyear sea ice variability observed from satellites: a review

In comparison with seasonal sea ice(first-year ice,FY ice),multiyear(MY) sea ice is thicker and has more opportunity to survive through the summer melting seasons.Therefore,the variability of wintertime MY ice plays a vital role in modulating the variations in the Arctic sea ice minimum extent during the following summer.As a response,the ice-ocean-atmosphere interactions may be significantly affected by the variations in the MY ice cover.Satellite observations are characterized by their capability to capture the spatiotemporal changes of Arctic sea ice.During the recent decades,many active and passive sensors onboard a variety of satellites(QuikSCAT,ASCAT,SSMIS,ICESat,CryoSat-2,etc.) have been used to monitor the dramatic loss of Arctic MY ice.The main objective of this study is to outline the advances and remaining challenges in monitoring the MY ice changes through the utilization of multiple satellite observations.We summarize the primary satellite data sources that are used to identify MY ice.The methodology to classify MY ice and derive MY ice concentration is reviewed.The interannual variability and trends in the MY ice time series in terms of coverage,thickness,volume,and age composition are evaluated.The potential causes associated with the observed Arctic MY ice loss are outlined,which are primarily related to the export and melting mechanisms.In addition,the causes to the MY ice depletion from the perspective of the oceanic water inflow from Pacific and Atlantic Oceans and the water vapor intrusion,as well as the roles of synoptic weather,are analyzed.The remaining challenges and possible upcoming research subjects in detecting the rapidly changing Arctic MY ice using the combined application of multisource remote sensing techniques are discussed.Moreover,some suggestions for the future application of satellite observations on the investigations of MY ice cover changes are proposed.     

基于多种高分辨率卫星数据的TRMM降水数据降尺度研究——以内蒙古地区为例

利用内蒙古地区2001~2010年42个站点实测降水数据作为“真值”,采用LOO（Leave-One-Out）交叉验证、多元逐步回归等方法,构建TRMM（Tropical Rainfall Measuring Mission）降水数据与地形及气候等要素之间的多元回归关系,在此基础上,利用回归值+残差值的方法,获得空间分辨率为1 km×1 km的TRMM年降水数据,并对降尺度TRMM数据进行精度检验。研究表明：① TRMM数据可用于区域年降水量估计,且与实测年降水量呈显著线性关系;② 通过建立不同年份、不同空间分辨率TRMM数据与其它遥感数据的多元统计模型,研究发现在中尺度下TRMM与观测年降水数据拟合效果较好,且在空间分辨率为0.50°×0.50°时的拟合效果最好;③ 降尺度分析提高了TRMM数据对研究区降水时空特征的描述能力,确定性系数、标准误差和偏差均有明显改善,表明降尺度算法在将TRMM降水数据空间分辨率提高到1 km×1 km的同时,并能提高降水数据的精度。