共查询到19条相似文献，搜索用时 625 毫秒
1.
陆面过程研究的现状与发展趋势 总被引：25，自引：4，他引：25
对目前陆面过程研究的现状及存在的问题进行了总结,并且提出了与边界层研究有关的几个前沿方向:①非均匀下垫面地表湍流通量的参数化及中尺度通量的参数化方法;②边界层理论在复杂地形条件下的应用,以及次网格地形对通量输送的影响;③进一步改进GCM中冠层地表水文参数化;④边界层的层云和层积云的参数化。 相似文献
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西北干旱区陆-气相互作用试验(NWC-ALIEX)及其研究进展 总被引：44，自引：8，他引：36
简要阐述了国家重点基础研究发展规划项目“我国重大气候和天气灾害形成机理和预测理论的研究”支持的“我国西北干旱区陆—气相互作用野外试验（NWC ALIEX）”的科学意义、试验方案和科学目标,总结了该试验在最近几年取得的部分研究进展和研究成果,概括叙述了该项目在地表辐射平衡和热量平衡、总体输送系数、陆面过程参数、湍流通量参数化和地表水分循环以及陆面过程模式的改进和陆面过程的模拟等许多方面的重要发现和一些新的认识。最后,提出并讨论了在干旱区陆面过程方面需要进一步研究和思考的一些重要科学问题。 相似文献
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大孔径闪烁仪研究区域地表通量的进展 总被引：15，自引：0，他引：15
地表湍流通量包括感热通量和潜热通量的准确测定对天气气候、农业、水文和水资源管理等意义重大。在几公里到几十公里尺度上有代表性的区域湍流通量的观测研究,特别在非均匀下垫面情况下,仍然非常困难。近年来蓬勃发展的大孔径闪烁仪（LAS）为这一问题的解决提供了全新手段。在介绍大孔径闪烁仪原理的基础上,综述了国内外利用大孔径闪烁仪开展区域地表通量观测研究的进展,包括在不同地表的LAS测量与涡动相关方法有关结果的对比,影响测量精度的关键因子分析,以及在区域地表通量遥感估算模型检验中的应用等,最后对大孔径闪烁仪的应用前景进行了展望。 相似文献
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基于多尺度遥感数据估算地表通量的方法及其验证分析 总被引：2，自引：0，他引：2
地表水热通量(显热通量、潜热通量)的遥感估算在全球气候变化、水资源、生态环境等研究领域具有重要的应用价值.MODIS数据的空间分辨率较低(热红外波段星下点为1 km),而地球表面的几何物理属性又具有高度非均匀性,因而在实际应用中面临较严重的尺度问题.探讨了多源卫星数据(中高分辨率Landsat TM与中低分辨率MODIS)相结合佑算像元通量的2种方法,分别利用高分辫率的地表分类及植被指数信息在混合像元内部进行亚像元处理,以提高非均匀地表混合像元的通量估算精度.研究数据来自于2008年黑河流域综合实验获取的遥感数据和辅助数据,验证数据来自于实验期间获取的不同下垫面的地表通量数据,包括涡度相关(EC)数据,以及大孔径闪烁仪(LAS)数据.计算结果表明,2种方法皆可在下垫面不均匀或者地表类型较复杂的情况下得到比较明显的纠正效果,纠正后的通量与观测更加接近.相比之下,利用植被指数分解温度的方法适用性更广,纠正效果更好.在地面验证中,对比分析了EC和LAS数据在TM尺度和MO-DIS尺度通量验证的适用性.LAS数据测量尺度与MODIS卫星像元尺度相匹配,可以直接验证MODIS通量计算结果,EC数据虽然可以直接验证TM计算的通量,但与MODIS数据对比,还需要进行尺度转换,即先用EC验证TM通量,然后将TM通量降尺度,与MODIS进行对比.最后对利用LAS验证通量的不确定性进行了分析,发现图像中LAS测点的几何定位误差以及LAS测量路径中像元的选取都对验证结果有一定影响. 相似文献
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城市陆面过程与边界层结构研究 总被引：6，自引：1，他引：5
通过城市边界层观测、卫星遥感以及城市边界层数值模拟等途径,获取对城市陆面过程特性的认识,研究建立精细城市边界层模式,引入合理城市区陆面过程参数化方案,并进行城市边界层结构影响研究。研究结果表明：①城市下垫面能量平衡过程迥异于自然地表,引入合理的参数化方案是改善数值模拟性能的关键。②高分辨卫星观测信息是认识城市地表参数状况及其变化的有效途径。 ③人为热排放参数化方案的合理引入是准确描述地表能量平衡过程的又一重要课题。需根据实际情况确定人为热排放的引入方案及量值变化。④应从合理描述城市建筑物下垫面对热力输送及大气动力场的影响出发,研究建立了多层城市冠层模式。⑤应建立更完善的多尺度城市边界层模式系统并引入更新的城市效应参数化方案和数据同化处理,以增强并完善城市边界层数值模拟能力。 相似文献
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青藏高原复杂地表能量通量研究 总被引：4，自引：0，他引：4
“全球能量水循环之亚洲季风青藏高原试验研究”（GAME/Tibet）和“全球协调加强观测计划（CEOP）亚澳季风之青藏高原试验研究”（CAMP/Tibet）的加强期观测和长期观测已经进行了9年多,并且已取得了大量的珍贵资料。首先介绍了GAME/Tibet 和CAMP/Tibet 试验的情况,并利用观测资料给出了局地能量分布（日变化和月际变化）特征。复杂地表区域能量通量研究是青藏高原地气相互作用研究中的重中之重。卫星遥感的应用成为解决这一问题,即实现GAME/Tibet和CAMP/Tibet试验主要初衷的必不可少的手段。利用卫星遥感观测（Landsat 7 ETM）资料结合地面观测的方法,计算得到了相关地区非均匀地表区域上的地表温度、地表反射率、标准化差值植被指数(NDVI)、校准的调整土壤植被指数（MSAVI）、植被覆盖度和叶面指数(LAI)及能量平衡各分量（净辐射通量、土壤热通量、感热和潜热通量）的分布图像,所得结果基本可信。为了得到整个青藏高原复杂地表的热通量分布,中国科学院青藏高原研究所正在与其他研究单位一起建立青藏高原地表和大气过程监测系统（MORP）。最后介绍了该监测计划和已建立的3个综合观测研究站及如何利用建立的台站把站点观测的热通量推广到整个青藏高原的途径。 相似文献
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黑河流域生态—水文过程综合遥感观测联合试验总体设计 总被引：17，自引：4，他引：13
介绍了"黑河流域生态—水文过程综合遥感观测联合试验"的背景、科学目标、试验组成和试验方案。试验的总体目标是显著提升对流域生态和水文过程的观测能力,建立国际领先的流域观测系统,提高遥感在流域生态—水文集成研究和水资源管理中的应用能力。由基础试验、专题试验、应用试验、产品与方法研究和信息系统组成。其中,①基础试验:搭载微波辐射计、成像光谱仪、热像仪、激光雷达等航空遥感设备,开展一系列关键生态和水文参量的观测;发展遥感正向模型及反演和估算方法。形成覆盖全流域的水文气象综合观测网,为流域生态—水文模型研究提供更有代表性的模型参数、驱动数据及更高精度的验证数据。构建无线传感器网络,度量生态水文模型所需的若干关键的驱动、参数和模型状态的空间异质性。开展航空遥感定标和地基遥感试验。依托传感器网络,并辅之以地面同步和加密观测,开展遥感产品真实性检验。②专题试验:开展"非均匀下垫面多尺度地表蒸散发观测试验",采用密集的涡动相关仪、大孔径闪烁仪与自动气象站的观测矩阵,为揭示地表蒸散发的空间异质性,实现非均匀下垫面地表蒸散发的尺度扩展,发展和验证蒸散发模型提供基础数据。③应用试验:在流域上、中、下游分别开展针对积雪和冻土水文、灌溉水平衡和作物生长、生态耗水的综合观测试验,将观测数据和遥感产品用于上游分布式水文模型、中游地表水—地下水—农作物生长耦合模型、下游生态耗水模型,通过实证研究提升遥感在流域生态—水文集成研究和水资源管理中的应用能力。加强试验将在2012年5月起按中游、上游、下游的顺序展开,全流域持续观测期为2013—2015年。在各类试验的支持下,开展全流域生态—水文关键参量遥感产品生产,发展尺度转换方法,建立多源遥感数据同化系统。 相似文献
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目前通用的通量观测技术涡动相关仪（EC）在区域陆面模式验证中存在能量不闭合和空间代表性有限的问题,寻求改进EC观测热通量的新技术是提高陆面模式验证效果的关键环节,大孔径闪烁仪（LAS）的出现有效改善了这一现状。基于黄土高原定西站2010年1月和6月的同步综合观测资料以及目前比较有代表性的陆面过程模式CLM的模拟数据,分析研究了LAS对EC观测地表能量不平衡问题的改进以及LAS对EC在区域陆面模式验证中的提高,结果表明：LAS可有效解决EC观测存在的地表能量不平衡问题,提高EC的地表能量闭合度,在非均匀下垫面LAS观测优势突出;利用LAS观测的感热通量进行区域陆面模式的验证,能够很大程度地避免EC能量不闭合和空间尺度不匹配在验证中造成的偏差,LAS观测更适合于大尺度模拟的验证,验证效果更好。 相似文献
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由于近地表模型速度结构的非均匀性,导致基于均匀网格的近地表速度模型很难达到最优,并同时存在信息冗余的弊端,由此提出了非均匀网格层析静校正方法。非均匀网格化建模方法基于背景速度场、地质构造带速度结构,以及目标地质图速度模型进行三级网格划分,运用一定的追踪方法获取方位角信息与地表初至波走时,将初至波观测走时与计算走时之间的时差分至追踪到各网格中,经近地表速度模型的多次迭代,构建最终速度模型。采用该方法在近地表速度纵、横向变化剧烈地区得到的静校正时间剖面,与其他常规校正方法比较,静校正效果较好。 相似文献
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黄土高原陆面过程试验研究(LOPEX)有关科学问题 总被引：28，自引：7，他引：21
主要讨论了黄土高原陆面过程野外科学试验研究项目的有关科学技术问题。首先从科学和现实角度说明了开展黄土高原陆面过程试验研究（LOPEX）的意义,并从黄土高原陆面过程野外观测和特征分析、黄土高原陆面水分过程特征及其对生态生理过程的影响、黄土高原陆面过程参数化研究等3个方面介绍了该科学试验研究项目的主要研究内容和重点要解决的科学问题,而且还初步探讨了黄土高原陆面过程试验研究的技术难点以及解决这些技术难点的主要科学技术思路。 相似文献
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Chandra M. Kishtawal Dev Niyogi Anil Kumar Monica Laureano Bozeman Olivia Kellner 《Natural Hazards》2012,63(3):1527-1542
Using the HURDAT best track analysis of track and intensity of tropical cyclones that made landfall over the continental United States during the satellite era (1980?C2005), we analyze the role of land surface variables on the cyclone decay process. The land surface variables considered in the present study included soil parameters (soil heat capacity and its surrogate soil bulk density), roughness, topography and local gradients of topography. The sensitivity analysis was carried out using a data-adaptive genetic algorithm approach that automatically selects the most suitable variables by fitting optimum empirical functions that estimates cyclone intensity decay in terms of given observed variables. Analysis indicates that soil bulk density (soil heat capacity) has a dominant influence on cyclone decay process. The decayed inland cyclone intensities were found to be positively correlated with the cube of the soil bulk density (heat capacity). The impact of the changes in soil bulk density (heat capacity) on the decayed cyclone intensity is higher for higher intensity cyclones. Since soil bulk density is closely related to the soil heat capacity and inversely proportional to the thermal diffusivity, the observed relationship can also be viewed as the influence of cooling rate of the land surface, as well as the transfer of heat and moisture underneath a land-falling storm. The optimized prediction function obtained by statistical model processes in the present study that predicts inland intensity changes during 6-h interval showed high fitness index and small errors. The performance of the prediction function was tested on inland tracks of eighteen hurricanes and tropical storms that made landfall over the United States between 2001 and 2010. The mean error of intensity prediction for these cyclones varied from 1.3 to 15.8 knots (0.67?C8.12?m?s?1). Results from the data-driven analysis thus indicate that soil heat flux feedback should be an important consideration for the inland decay of tropical cyclones. Experiments were also undertaken using Weather Research Forecasting (WRF) Advanced Research Version (ARW ver 3.3) to assess the sensitivity of the soil parameters (roughness, heat capacity and bulk density) on the post-landfall structure of select storms. The model was run with 1-km grid spacing, limited area single domain with boundary conditions from the North American Regional Reanalysis. Of different experiments, only the surface roughness change and soil bulk density (heat capacity) change experiments showed some sensitivity to the intensity change. The WRF results thus have a low sensitivity to the land parameters (with only the roughness length showing some impact). This calls for reassessing the land surface response on post-landfall characteristics with more detailed land surface representation within the mesoscale and hurricane modeling systems. 相似文献
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Land surface temperature on alpine mountainous cold regions, which is one of basic parameters of the regional hydrological and meteorological conditions, directly affects glacial recession, snow melt, distribution and freezing thawing process of permafrost, evapotranspiration, vegetation growth, and various underlying surface change process, and then changes the regional hydrological and ecological environment, becomes the important parameter of the research on land surface process and the study of eco-hydrological process. This paper tried to provide an overview of research on land surface temperature, and to introduce its influence factors and the ways to obtain land surface temperature data in high mountainous cold region. Relative to low elevation plain, the land surface temperature was significantly affected by local altitude, terrain and plant cover. There were some methods to obtain land surface temperature, such as measurement in situ, retrieval based on remote sensing and calculation by land surface process models, but there were some limitations while used on alpine mountainous cold regions. Land surface temperature data from meteorological stations were only about level bare ground, and the influence of terrain or vegetable cover was not considered. Therefore, the data could not represent the information of region scale on mountainous area. Land surface temperature retrieval from remote sensing data, because of calculation theory, ground observation verification and spatiotemporal resolution, made it difficult to fulfill research on hydrology, land surface process and eco-hydrological process in alpine mountainous area. Land surface process models estimated land surface temperature in the experimental sites with high accuracy, but reduced the accuracy while upscale to the region scale on the mountainous cold area, because of the error from input control meteorological, soil and plant variables, and the error of ground observation site verification. The future research on land surface temperature on alpine mountainous cold regions should strengthen field observations and improve data accuracy, to build a physical land surface temperature estimation method with topographic and vegetation parameters, and to contribute to research on land-atmosphere-water process in alpine mountainous regions. 相似文献
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The water resource and its change of mountainous area are very important to the oasis economic system and ecosystem in the arid areas of northwest China. Accurately understanding the water transfer and circulation process among vegetation, soil, and atmosphere over different hydrological units in mountainous areas such as snow and ice, cold desert, forest and grassland is the basic scientific issue of water research in cold and arid regions, which is also the basis of water resource delicacy management and regulation. There are many research results on the hydrological function of different land covers in mountain areas, basin hydrological processes, however, there are only very limited studies on the water internal recycle at basin scale. The quantitative study on the mechanism of water internal recycle is still at the starting stage, which faces many challenges. The key project “Study on water internal recycle processes and mechanism in typical mountain areas of inland basins, Northwest China” funded by National Natural Science Foundation of China will select the Aksu River and Shule River Basin, which have better observation basis, as study area. The internal mechanism of moisture transfer and exchange process of different land cover and atmosphere, the internal mechanism of water cycle in the basin, and water transfer paths in atmosphere will be studied through enhancing runoff plot experiments on different land cover, analyzing the mechanism of water vapor transfer and exchange between different land covers in the watershed by isotope tracing on the water vapor flux of vegetation water, soil moisture and atmospheric moisture, improving the algorithms of remote sensing inversion and ground verification on land surface evapotranspiration on different land cover, and analyzing the water vapor flux from reanalysis data, and the coupling modeling of regional climate model and land surface process model. At last, the effect of different land cover in hydrological process of mountain area, and the impact of land cover on downstream oasis will be systematically analyzed. 相似文献
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关于黄土高原陆面过程及其观测试验研究 总被引：8，自引：0，他引：8
总结了国际上陆面过程及其试验研究的现状,分析了黄土高原陆面过程的特殊性和重要意义,探讨了黄土高原陆面过程试验研究中需要关注的一些重要科学问题。并且,对如何开展黄土高原陆面过程试验研究提出了一些初步思路。 相似文献
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长白山地区主要断裂带与地表温度场关系研究 总被引：1，自引：0，他引：1
基于Landsat 5 TM和Landsat 7 ETM+影像,采用辐射传输方程法反演长白山地区地表温度,以已知断裂带为中心线,向两侧相同范围做等间距划分,统计各等分带内的平均地表温度和平均距离,运用图形的形式展现温度场和断裂构造之间的关系,并用等分带平均温度和平均距离绘制相关性曲线来进一步描述温度场与主要断裂构造之间的关系。结果表明:9月份时区域内的6条断裂带与地表温度场相关性显著,区域特征稳定,等分带内距离断裂带越远,地表温度越低;4月份时地表温度场随断裂构造的变化趋势和11月份时地表温度场随断裂构造的变化趋势呈现出很大程度的吻合。区域内的北东向和近东西向断裂带,其地表温度场与断裂构造之间表现出一定的相关性,北西向的北岗断裂带、红旗村—天池断裂带以及漫江断裂带与地表温度场的相关性并不显著,红旗村—天池温度场与漫江温度场可能属于一个更大尺度的温度场的两侧。 相似文献
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遥感技术应用于地表面蒸散发的研究进展 总被引：31，自引：4，他引：27
蒸散既是地表水分循环的重要组成部分,也是能量平衡的主要项。地表热量、水分收支状况在很大程度上决定着地理环境的组成和演变,清楚地认识蒸散发,对了解大范围内能量平衡和水分循环具有重要意义。目前,已发展了从
传统方法、模拟方法到遥感方法的很多种方法用于估算蒸散发。遥感方法以其能够获知大范围地表特征信息的优势为较准确估算地表蒸散发提供了可能,从而受到人们的日益重视。介绍了研究蒸散发的各种方法,并探讨了利用遥感方法研究蒸散发的优缺点和未来的发展前景。 相似文献
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Assessment of temporal and spatial variability of soil salinity in a coastal saline field 总被引：1，自引：0，他引：1
Many coastal tideland areas in southern Hangzhou Gulf in Zhejiang Province of China have been successively enclosed and reclaimed for agricultural land uses under a series of reclamation projects over the past 30 years. The variability of soil salinity was considerably great and an understanding of the temporal and spatial components of soil salinity variability is essential before decisions can be made about the feasibility of site-specific management. In this paper, a 5.35-ha field reclaimed in 1996 was selected as the study site and 112 bulk electrical conductivity (ECb) measurements were performed in situ by a hand held device in the topsoil (0–20 cm) at regular 20-m intervals across the field over a two-year period. Conventional statistics and geostatistical techinques were used to assess the spatial variability and temporal stability of soil-salinity distribution. The results indicated high coefficients of variation in topsoil salinity over the three samplings. Simple mean ECb comparison revealed that soil salinity increased from winter to spring. Kriged contour maps showed the spatial trend of salinity distribution and revealed the consistently high and low salinity areas of the field. In percentage terms, the proportions of the moderately saline class, strongly saline class, and extremely saline class were 37, 39, and 24%, respectively. Temporal stability map indicated that more than 60% of the study field was determined as the stable class. Based on the spatial and temporal characteristics, a similarity assessment map was created, which presented 5 homogenous sub-zones, each with different characteristics that can have an impact on the way the field is managed. It was concluded that saline soil land might be managed in a site-specific way based on the clearly defined management sub-regions within the field. 相似文献