Estimation of the Land Surface Emissivity in the Hinterland of Taklimakan Desert   总被引：3，自引：2，他引：1  

LIU Yong-qiang  Ali MAMTIMIN  HUO Wen  YANG Xing-hua  LIU Xin-chun  MENG Xian-yong  HE Qing 《山地科学学报》2014,(6):1543-1551

An accurate accounting of land surface emissivity(ε) is important both for the retrieval of surface temperatures and the calculation of the longwave surface energy budgets.Since ε is one of the important parameterizations in land surface models(LSMs),accurate accounting also improves the accuracy of surface temperatures and sensible heat fluxes simulated by LSMs.In order to obtain an accurate emissivity,this paper focuses on estimating ε from data collected in the hinterland of Taklimakan Desert by two different methods.In the first method,ε was derived from the surface broadband emissivity in the 8–14 μm thermal infrared atmospheric window,which was determined from spectral radiances observed by field measurements using a portable Fourier transform infrared spectrometer,the mean ε being 0.9051.The second method compared the observed and calculated heat fluxes under nearneutral atmospheric stability and estimated ε indirectly by minimizing the root-mean-square difference between them.The result of the second method found a mean value of 0.9042,which is consistent with the result by the first method.Although the two methods recover ε from different field experiments and data,the difference of meanvalues is 0.0009.The first method is superior to the indirect method,and is also more convenient.  相似文献   

Characteristics and tectonic setting of volcanic rocks in Early Cretaceous Baiyingaolao Formation of Keyouzhongqi area，Inner Mongolia   总被引：1，自引：0，他引：1  

KONG Yuanming  MA Rui  HE Zhonghua  YANG Deming  WU Qing  WANG Yang 《世界地质(英文版)》2014,17(2):78-85

The authors studied zircon LA-ICP-MS U-Pb dating,the zircon Hf isotope and geochemistry of acidic volcanic rocks in Baiyingaolao Formation of Keyouzhongqi area,Inner Mongolia,and discussed the chronology, source region and tectonic setting of the volcanic rocks in the studied area． The clear oscillatory zoning of zir- cons indicates a typical magmatic origin,and the results of dating show that the volcanic rocks of Baiyingaolao Formation were formed in Early Cretaceous (121.5 ±1.0 Ma)． The features of major and trace elements show that the rocks are alkali-rich,poor in calcium and magnesium with enrichment in LILEs like Th,U,K and Gd and depletion in HFSEs,e.g. Nb,Ta,Sr and Ti． The fact implies that they were the products of partial melting of the crust． εHf(t) = ( +6.30--+9.06) and TDM2=600--835 Ma,suggest the magma originated from par- tial melting of the young crust． Combined with the evolution of regional tectonic structure,the authors conclude that the acidic volcanic rocks of Baiyingaolao Formation may be formed under the extensional environment relat- ed to the subduction of Paleo-Pacific Plate．  相似文献   

Petrogenesis and tectonic setting of granite porphyry in Keyouzhongqi area,Inner Mongolia     

WU Qing  YANG Weihong  HE Zhonghua  YANG Deming  MA Rui  WANG Jianguo 《世界地质(英文版)》2014,17(1):24-33

The authors studied the geochemistry,zircon U-Pb ages,Hf isotope of the granite porphyry and its petrogenesis and tectonic setting in the studied area． The zircon U-Pb dating indicates the formation of the gran- ite porphyry is in Early Cretaceous (125． 1 ±1． 5 Ma)． The granite porphyry has high-SiO2and alkali-rich fea- tures,which belongs to high-K calc-alkaline series rocks (A/CNK = 0． 95%--1． 25%)． The analyses of trace elements show the characteristics of a swallow-shaped ＲEE distribution pattern with enrichment in LＲEEs and most of LILEs and HFSEs,depletion in Ba,Sr,Nb,P and Ti,and especially strong depletion in Eu,which indicates the granite porphyry belongs to the aluminous A-type granite． Their εHf(t)range from 5． 94 to 8． 80 with Hf two-stage model ages (TDM2) of 620 Ma to 803 Ma． Combining with the regional tectonic background, we conclude that the source of the rocks is the new crust materials accreted from depleted mantle in Neoprotero- zoic and is the product of partial melting of middle and lower crustal rocks,which may be suffered from the dual impact of the subduction of the Palaeo-Pacific Ocean and the closure of the Mongol-Okhotsk Ocean．  相似文献   

可控源法在海阳市郭城地区鑫泰金矿床成矿规律中的应用          下载免费PDF全文

郭国强  郭朋  张超  何玉海  于义文  陈大磊 《山东国土资源》2014,30(6)

可控源音频大地电磁法(CSAMT法)是一种利用人工场源研究地层、构造等深部地质特征问题的新技术新方法。在山东省海阳市郭城地区鑫泰金矿床的应用研究表明,CSAMT法可以较好地用于确定矿体的产状和大致地层结构,在矿体成矿规律研究方面具有较为突出的应用效果。  相似文献   

1990年以来中国小麦农业气象灾害时空变化特征(英文)     

张朝  王品  陈一  张帅  陶福禄  刘晓菲 《地理学报(英文版)》2014,24(3):387-396

Agro-meteorological disasters(AMD) have become more frequent with climate warming. In this study, the temporal and spatial changes in the occurrence frequency of major meteorological disasters on wheat production were firstly explored by analyzing the observed records at national agro-meteorological stations(AMS) of China from 1991 to 2009. Furthermore, impact of climate change on AMD was discussed by comparing the warmer decade(2000–2009) with another decade(1991–2000). It was found that drought was the most frequent disaster during the last two decades, with a highest proportion of 79%. And the frequency of AMD increased significantly with climate change. Specifically, the main disasters occurred more frequently in the reproductive period than in the vegetative period. Besides, the spatial changes in the AMD frequency were characterized by region-specific. For example, the wheat cultivation areas located on the Loess Plateau and the middle-lower reaches of the Yellow River suffered mainly from drought. All these results were strongly linked to climate change in China. Therefore, sound adaptation options should be taken based on the latest changes of AMD under global warming to reduce agricultural damages.  相似文献   

CMIP5全球气候模式对中国地区干旱变化模拟能力评估     

张冰  巩远发  徐影  张帅 《干旱气象》2014,(5)

利用东亚地区1961～2005年高分辨率（0．5°×0．5°）降水格点数据和参加CMIP5的42个全球气候模式数值模拟结果,通过对简单降水强度指数（降水距平百分率）的计算,对比分析了观测和多模式集合的中国地区干旱面积、干旱频率的时空分布以及干旱分布型的变化,评估了全球气候模式的模拟能力。结果表明：多个全球气候模式的集合结果对中国区域的干旱变化特征有一定的模拟能力,能较好地模拟出中国年平均干旱指数的时间变化趋势,但模拟的干旱强度偏弱;多模式集合模拟的严重干旱面积与观测值的变化趋势基本一致,与观测相比,模拟的长江以南干旱强度偏强,西北干旱强度偏弱;通过EOF的分析表明,多模式集合可以较好地模拟出西北与长江以南呈反位相及我国东部地区的“旱-涝-旱”或“涝-旱-涝”的分布型。  相似文献   

高寒地区日光温室地温变化及预报   总被引：2，自引：0，他引：2  

朱宝文  胡德奎  郭晓宁  何永晴 《干旱气象》2014,(5):765-772

利用2012年4月至2013年3月青海大通县日光温室内外地温、气温资料和大通县气象站人工观测资料,分析了高寒冷凉地区不同天气类型下日光温室地温变化规律。结果表明;研究区日光温室内日地温呈正弦曲线变化,晴天变化幅度最明显,阴天最小,地温变幅为地表〉5 cm〉10 cm〉15cm〉20 cm;室内地表、10 cm和20 cm平均地温月变化呈波形变化,最大值出现在7月,最小值在12月;随着深度增加,平均地温年较差逐渐减小;晴天、多云天、阴天不同深度地温平均日较差分别为9.6、8.3、6.1℃;地温日垂直变化仅在14时随着深度增加逐渐下降;除晴天室内最高温度外,其余温度要素与地温之间存在极显著正相关关系;建立的日光温室内10 cm最低温度预报方程和地表最低温度预报模型,可以在业务服务中应用。  相似文献   

西风角动量输送的气候特征及其与急流关系研究     

杨玮  王盘兴  何金海  李丽平  成丽萍 《大气科学》2014,38(2):363-372

利用1958～1997年NCEP/NCAR一日四次的风场再分析资料,系统地分析了季节平均西风角动量（即u角动量）经向、垂直输送通量及其三个分量（平均经圈环流、定常波、瞬变涡输送通量）的气候特征,特别是讨论了12～2月、6～8月它们与东、西风带、副热带西风急流、极夜急流之间的联系。结果表明:（1）包含纬度因子的角动量通量与动量通量在高纬地区存在显著差别,高纬对流层上部的强动量输送中心在角动量通量中不明显。而u角动量强经向输送主要在中低纬对流层顶附近和冬半球高纬平流层顶附近,副热带西风急流和极夜西风急流均位于u角动量强向极输送中心及其高纬一侧的辐合区中。（2）发现三个输送分量对急流维持的作用随纬度、季节不同。北半球冬季（夏季）的副热带西风急流主要由平均经圈环流（强度相当的定常波和瞬变涡）强经向输送及辐合维持;南半球西风急流全年均由平均经圈环流和瞬变涡旋输送及辐合维持;冬半球中平流层极夜急流主要由定常波、瞬变涡旋输送及其辐合共同维持。（3）热带东风区是牵连角动量（即Ω角动量）的高值区,它主要由平均经圈环流向对流层上部输送;冬半球副热带及中纬西风区存在u角动量垂直输送的切变区,它主要由平均经圈环流和瞬变涡旋完成;热带对流层顶附近有u角动量的定常波弱向下输送。  相似文献   

复杂地形区陆面资料对WRF模式模拟性能的影响   总被引：2，自引：0，他引：2  

何建军  余晔  刘娜  赵素平  陈晋北 《大气科学》2014,38(3):484-498

本文利用WRF（Weather Research and Forecasting）模式耦合Noah陆面过程模式,对比研究了使用不同精度陆面资料:WRF默认陆面资料、中国1 km分辨率数字高程模型数据集、2006年MODIS（MODerate-resolution Imaging Spectroradiometer）土地利用和植被覆盖度资料,WRF模式对兰州地区冬季气象场模拟结果的差异。结果表明,近地面气温对陆面资料的精度非常敏感,而风场对陆面资料的精度不敏感,WRF模式对气温的模拟效果好于对风场模拟。采用高精度且时效性好的陆面资料后,WRF模拟的近地面气温准确率提高了15.8%,模拟的夜间气温改进幅度较白天大。陆面资料可影响整个边界层温度场分布,准确的陆面资料对提高WRF模式模拟近地面乃至整个边界层气象场至关重要。尽管风速模拟误差较大,但总体上WRF模式能较准确地模拟出研究区的风场演变特征。使用新的陆面资料后WRF模拟的风速误差略有减小,风向误差略有增加。干旱半干旱区冬季数值模拟需要注意土壤湿度初值和模式初始积分时刻对模拟结果的影响。  相似文献   

基于NCEP风向数据的中国夏季降水估算研究     

高婷  曾燕  何永健  邱新法 《气象科学》2014,34(5):473-482

提出一个基于NCEP风向数据估算全国夏季降水的模型。根据NCEP地面气压、经纬向风数据计算得到全国1971—2000年夏季各月盛行风向;并将盛行风向与宏观坡向夹角的余弦值作为降水的坡向因子,以此区分山体迎风坡和背风坡降水的空间分布。利用站点观测资料、数字高程模型数据、坡向、坡度因子,采用逐步回归分析法,建立估算夏季降水的回归方程,得到全国1971—2000年夏季各月及总降水量的空间分布图,并对模型结果进行检验与对比分析。结果表明,此方法估算夏季总降水量的平均绝对误差为27 mm,平均相对误差为11.8%。模型结果能体现迎风坡与背风坡的雨量差,符合客观规律,能够定性、定量地再现中国夏季降水的实际空间分布特征。  相似文献