OLR方法在黑龙江地区中强地震前异常现象的探讨     

王春  齐晓燕  高峰 《地震地磁观测与研究》2011,32(6):8-12

利用卫星遥感长波辐射(OLR)资料,分析黑龙江省2004年-2008年发生的几次ML 4.0以上中强地震前的OLR资料,发现地震发生前,在震中附近地区有长波辐射增强的特征,可能与强震孕育过程中的热状态有关,识别和提取卫星对地遥感红外波段的热兆信息,可望在中强地震监测预报的层面上有新的突破.  相似文献   

Surface energy and water vapor fluxes observed in a desert plantation in central Iran   总被引：1，自引：0，他引：1  

A. Oliphant  P. Zawar-rezaG. Azizi  A. DehghanpourJ. Harrison 《Journal of Arid Environments》2011,75(10):926-935

Summertime observations of surface radiation budget, energy balance and atmospheric surface layer meteorology were made on an arid valley floor planted with Haloxylon aphyllum to combat desertification in central Iran. The surface microclimate is characterized and compared with other arid regions and the role of ‘desert greening’ on surface fluxes is considered. A high surface albedo (0.265) and large longwave radiation loss produced relatively low net radiation. Energy partitioning was dominated by sensible and ground heat fluxes with opposing diurnal asymmetry governed by strong diurnal variability in eddy diffusivity. The Bowen ratio was 2.53, which fell inside the range of other vegetated arid surfaces. Surface temperature gradients were strong both in the atmospheric surface layer and in the substrate, with consistent lapse conditions by day and inversions at night. The wind regime included a moderate daytime regional wind which displayed Coriolis turning and weaker nocturnal slope flows. Actual evapotranspiration (1 mm dy⁻¹) was only a small fraction of potential evapotranspiration. The diurnal pattern of AET indicates strong stomatal control. The desert greening effect of Haloxylon plantations provided atmospheric water and reduced sensible heat flux by up to 40%.  相似文献   

MODELLING SURFACE‐AIR‐TEMPERATURE VARIATION OVER COMPLEX TERRAIN AROUND ABISKO,SWEDISH LAPLAND: UNCERTAINTIES OF MEASUREMENTS AND MODELS AT DIFFERENT SCALES     

ZHENLIN YANG  EDWARD HANNA  TERRY V. CALLAGHAN 《Geografiska Annaler: Series A, Physical Geography》2011,93(2):89-112

  相似文献   

基于辐射的潜在蒸散量估算方法适用性分析   总被引：2，自引：0，他引：2  

左德鹏  徐宗学  程磊  赵芳芳 《干旱区地理》2011,(4):565-574

根据不同气候区4个站的历史数据,选取8种基于辐射的PET估算方法,以FAO56-PM法计算的PET作为参考值进行比较分析,最后用20 cm蒸发皿蒸发量对所有方法在不同气候区的适用性进行评价.其结果表明,采用初始参数时,Hargreaves法在不同气候区估算的逐月以及多年月平均PET误差均较小,其它方法则产生较大误差.校...  相似文献   

基于GIS的区域经济统计分析模型研究及应用——以江西省为例     

李恒凯  刘小生  陈优良 《地域研究与开发》2011,30(4)

针对当前GIS软件不能有效满足区域经济统计分析的问题,提出了利用GIS技术重新构建区域经济统计分析模型的新思路。对该模型进行了具体建模和编程实现,并将该模型集成到区域经济统计分析系统中,最后利用该系统对江西省各地区经济进行了统计分析的应用实践。研究表明,该区域经济统计分析模型能够有效地应用于区域的经济统计分析,方便政府部门制定与经济相关的各种决策,具有广泛的应用推广价值。  相似文献   

淮河流域水文随机方法的径流图化(英文)     

严子奇  夏军 《地理学报(英文版)》2011,21(3):441-457

Theoretical difficulties for mapping and for estimating river regime characteristics in a large-scale basin remain because of the nature of the variable under study: river flows are related to a specific area, i.e. the drainage basin, and are hierarchically organized in space through the river network with upstream-downstream dependencies. Another limitation is there are not enough gauge stations in developing countries. This presentation aims at de-veloping the hydro-stochastic approach for producing choropleth maps of average annual runoff and computing mean discharge along the main river network for a large-scale basin. The approach applied to mean annual runoff is based on geostatistical interpolation proce-dures coupled with water balance and data uncertainty analyses. It is proved by an applica-tion in the upstream at Bengbu in the Huaihe River Basin, a typical large-scale basin in China. Hydro-stochasitic approach in a first step interpolates to a regular grid net and in a second step the grid values are integrated along rivers. The interpolation scheme includes a con-straint to be able to account for the lateral water balance along the rivers. Grid runoff map with 10 km × 10 km resolution and the discharge map along the river with the 1 km basic length unit are the main results in this study. This kind of statistic approach can be widely used be-cause it avoids the complexity of hydrological models and does not depend on the meteoro-logical data.  相似文献   

Changes in the Geometry and Volume of Rabots glaciär,Sweden, 2003–2011: Recent Accelerated Volume Loss Linked to More Negative Summer Balances          下载免费PDF全文

Keith A. Brugger  Latysha Pankratz 《Geografiska Annaler: Series A, Physical Geography》2015,97(2):265-278

Terminus geometry, ice margins, and surface elevations on Rabots glaciär were measured using differential GPS during summer 2011 and compared with those similarly measured in 2003. Glacier length over the eight years decreased by ～105 m corresponding to 13 m a^?1, a rate consistent with ice recession over the last several decades. Measured changes in surface elevations show that between 2003 and 2011 the glacier's volume decreased by ～27.6 ± 2.6 × 10⁶ m³, or 3.5 ± 0.3 × 10⁶ m³ a^?1. This compares favorably with an estimate of ?28.1 ± 2.6 × 10⁶ m³ based on a mass‐balance approach. The rate of volume loss appears, however, to have significantly increased after 2003, being substantially greater than rates determined for the intervals 1959–80, 1980–89, and 1989–2003. This increase corresponds to a sustained interval of more negative summer balances. Previous work suggests that as of 2003 Rabots glaciär had not yet completed its response to a ～1°C warming that occurred c. 1900, and thus the current marked increase rate of ice loss might reflect the effect of recent, or accelerated regional warming that occurred during the last decade superimposed on its continued response to that earlier warming.  相似文献   

利用LM-BP神经网络估算西北地区太阳辐射   总被引：1，自引：1，他引：0  

李净  王卫东  张福存 《干旱区地理》2015,38(3)

气候、生态、水文等模型的应用需要空间连续分布的太阳辐射数据,由于地形等条件的制约,气象站点的分布有限,无法利用稀少的站点获得空间连续分布的辐射数据,而BP(Back-propagation)神经网络模型对太阳辐射具有很好的预测性,但以往的研究都是基于单个站点估算太阳辐射,而且BP神经网络模型存在收敛速度慢、学习时间长等问题,为解决BP算法存在的不足,采用LM(Levenberg-Marquardt)算法优化后的BP神经网络(简称LM-BP神经网络)结合DEM(Digital Elevation Model)数据估算西北地区128个气象站点2011年的太阳总辐射月均值,通过乌鲁木齐和银川两台站的实测数据进行验证,两台站的平均百分比误差分别为2.89%和3.24%,平均偏离误差分别为0.27 MJ·m-2和0.61 MJ·m-2,且拟合优度均0.90。该模型各项误差指标较小,估算精度较高。最后将模型模拟出的辐射值,结合已有的24个辐射站点的实测值进行空间插值,得到西北地区2011年逐月太阳辐射精细化空间分布图。  相似文献   

极地冰盖物质平衡的最新进展与未来挑战          下载免费PDF全文

王慧孙波  李斐唐学远  崔祥斌王甜甜 《极地研究》2015,27(3):326-336

准确地探明冰盖物质平衡状况,对于研究全球变暖背景下海平面变化具有重要的意义,自IPCC AR4(政府间气候变化专门委员会第四次报告)以来,极地冰盖物质平衡的研究取得了很大进展。本文总结并对比了用卫星测高(雷达测高和激光测高)、物质收支测量和重力测量等方法得到的冰盖物质平衡评估结果,综述了冰盖数值模拟研究在预测冰盖未来的变化趋势以及由此对海平面造成的影响等方面取得的进展,并立足于中国当前的极地冰盖物质平衡研究现状,提出了该研究所面临的挑战。  相似文献   

Accounting for the solar radiation in thermal regime prediction for railway subgrade in cold regions     

Alexander Isakov  Anna Lavrova 《寒旱区科学》2015,7(4):293-299

This paper presents a comparative analysis of simulation processes of seasonal freezing-thawing of railway subgrade and permafrost degradation, with and without accounting for solar radiation. Also, the effect of sun screens to reduce the degradation of subgrade permafrost under different climatic conditions is numerically substantiated. And finally, the temperature criterion of the origination of permafrost is illustrated.  相似文献