黑河流域日蒸散发遥感估算研究   总被引：6，自引：2，他引：4       下载免费PDF全文

李星敏-  卢玲  李新  杨文峰  黄春林  王钊 《高原气象》2010,29(1):109-114

地表蒸散的估算在干旱半干旱区水资源研究中具有重要意义。利用NOAA/AVHRR遥感资料、NCEP再分析格点资料和气象站点资料,根据能量平衡模型和FAO-17 Penman公式,计算了研究区域内逐日蒸散发量;对于晴天,用遥感模型反演出瞬时蒸散,进而推算出日蒸散;同时用FAO-17 Penmen公式和气象资料,计算研究区域内的同一天的蒸散,利用气象资料计算得到的蒸散与遥感估算的蒸散的关系,估算非晴空日的蒸散,进而得到逐日蒸散发结果。与同类研究结果的比较表明:该方法能够估算逐日蒸散发,通过气象与遥感资料结合,提高了气象格点资料的空间分辨率,弥补了难以得到遥感逐日晴空资料的不足,同时也为流域内同类研究提供参考依据。  相似文献   

Carbon and water exchange in semiarid ecosystems in SE Spain     

F. Domingo  P. Serrano-Ortiz  A. Were  L. Villagarcía  M. García  D.A. Ramírez  A.S. Kowalski  M.J. Moro  A. Rey  C. Oyonarte 《Journal of Arid Environments》2011,75(12):1271-1281

The changing climate is affecting biological and physical processes occurring in the biosphere, including the biogeochemical cycles of water and carbon. The response of ecosystem carbon exchange to changes in temperature and the water balance is still very uncertain, a fact that highlights the need for research in order to understand the role of the biosphere in the future global carbon budget. South east Spain is on the borderline between the tropical and mid-latitude climate zones, with climates ranging from sub-humid to arid, and the majority representing the driest area in Europe. Initial predictions on climate change for this region point to decreases in total precipitation and the number of precipitation events, meaning a decrease in water availability underlining the vulnerability of the region to desertification. This region, due to these special climatic conditions, has been the subject of experimental carbon and water field research in recent years. This paper defines the state of the art of carbon and water balance measurement and modelling studies in this region, analyses the different processes involved in aggregate exchanges (vegetation and soil; net ecosystem carbon balance–evapotranspiration, photosynthesis–transpiration, soil respiration–evaporation), and identifies needs for future research.  相似文献   

Generation and evaluation of gross primary productivity using Landsat data through blending with MODIS data     

Devendra Singh 《International Journal of Applied Earth Observation and Geoinformation》2011

Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) has been used for the blending of Landsat and MODIS data. Specifically, the 30 m Landsat-7 ETM+ (Enhanced Thematic Mapper plus) surface reflectance was predicted for a period of 10 years (2000–2009) as the product of observed ETM+ and MODIS surface reflectance (MOD09A1) on the predicted and observed ETM+ dates. A pixel based analysis for six observed ETM+ dates covering winter and summer crops showed that the prediction method was more accurate for NIR band (mean r² = 0.71, p ≤ 0.01) compared to green band (mean r² = 0.53; p ≤ 0.01). A recently proposed chlorophyll index (CI), which involves NIR and green spectral bands, was used to retrieve gross primary productivity (GPP) as the product of CI and photosynthetic active radiation (PAR). The regression analysis of GPP derived from closet observed and synthetic ETM+ showed a good agreement (r² = 0.85, p ≤ 0.01 and r² = 0.86, p ≤ 0.01) for wheat and sugarcane crops, respectively. The difference between the GPP derived from synthetic and observed ETM+ (prediction residual) was compared with the difference in GPP values from observed ETM+ on the two dates (temporal residual). The prediction residuals (mean value of 1.97 g C/m² in 8 days) was found to be significantly lower than the temporal residuals (mean value of 4.46 g C/m² in 8 days) that correspondence to 12% and 27%, respectively, of GPP values (mean value of 16.53 g C/m² in 8 days) from observed ETM+ data, implying that the prediction method was better than temporal pixel substitution. Investigating the trend in synthetic ETM+ GPP values over a growing season revealed that phenological patterns were well captured for wheat and sugarcane crops. A direct comparison between the GPP values derived from MODIS and synthetic ETM+ data showed a good consistency of the temporal dynamics but a systematic error that can be read as bias (MODIS GPP over estimation). Further, the regression analysis between observed evapotranspiration and synthetic ETM+ GPP showed good agreement (r² = 0.66, p ≤ 0.01).  相似文献   

大型称重式蒸渗计的研制   总被引：11，自引：1，他引：11       下载免费PDF全文

柯晓新  林日暖 《应用气象学报》1994,5(2):151-157

介绍了安装在兰州干旱气象研究所定西综合试验站的大型称重式蒸渗计，它的有效蒸散面积4.0m2,原状土柱深约2.6m,测试精度0.1mm,是我国气象部门研制的第一台大型称重式蒸渗计。  相似文献   

A model for heat and water balance estimation and its application to land use and climate variation     

Janusz Olejnik  Andrzej Kedziora 《地球表面变化过程与地形》1991,16(7):601-617

This paper presents a method, which has been recently developed in the Department of Agrometeorology of the Poznań Agricultural University, for estimating heat balance components based on standard meteorological data, plant development stage, and land-use conditions. Estimates of latent heat flux components made it possible to obtain values of areal evapotranspiration and surface runoff. The method was applied in four catchment areas in Central Poland under present climatic conditions as well as under new, expected climatic conditions caused by an increase of ‘greenhouse gases’ in the atmosphere. Some changes in land use were also considered. The results show significant changes in the water balance when comparing present and future conditions of precipitation and evapotranspiration.  相似文献   

河北平原区域蒸发蒸腾量遥感估算     

蔺文静  董华  王贵玲  Z.Su  陈立 《国土资源遥感》2008,(1):86-90,I0007

地表能量平衡系统(SEBS)是一种基于遥感影像的区域地表通量估算模型,能够对区域蒸发蒸腾进行精确估算.在SEBS模型的基础上,以河北平原为例,采取中分辨率成像光谱辐射仪(MODIS)产品影像,根据研究区下垫面的实际情况进行了参数估算,区域实际蒸发蒸腾量计算及模型精确度评价,并在此基础上,结合研究区的地面覆盖,对河北平原区域蒸发蒸腾分布进行了分析.  相似文献   

黄河流域蒸散发与气温和降水以及风速的相关性分析     

谷同辉  管晓丹  高照逵  黄小倩  郭书扬 《气象与环境学报》2022,38(1):48-56

黄河流经我国干旱半干旱地区,其流域蒸散发变化对当地的生态安全和经济发展尤其重要。本文利用欧洲中期天气预报中心第五代再分析产品（ERA5）定量分析了1979-2020年黄河流域蒸散发的时空变化特征,并结合气温、降水和风速数据,对黄河流域蒸散发与3种气候因子进行了相关性分析。结果表明：黄河流域蒸散发在1979-2020年呈波动下降趋势,空间分布差异明显,源区附近蒸散发上升,上游的干旱区附近蒸散发基本不变,而中游和下游地区主要呈现下降趋势。1979-2020年黄河流域气温持续上升,降水呈波动下降趋势,风速呈上升趋势。对黄河流域蒸散发与气候因子的相关性分析表明,蒸散发与气候因子的相关性空间差异较为明显,蒸散发与气温、风速呈负相关,与降水呈正相关的区域占流域的较大部分;而在复相关性方面,黄河流域大部分地区蒸散发与气候因子的相关性较强,其中以流域上游的干旱区附近复相关性最强。研究黄河流域不同地区蒸散发与气候因子的相关性可为黄河流域水资源的开发管理和区域气候调节提供科学参考。  相似文献   

蒸散发时间尺度转换在日降雨径流过程模拟中的应用     

李相虎  任立良  张奇  王刚 《湖泊科学》2010,22(5):749-756

针对目前研究蒸散发时间尺度转换方面的不足,构建了月蒸散发时间尺度转换模型,对淮河史灌河流域黄泥庄小流域1982-1987年月蒸散发能力进行逐栅格解集,并与改进后的AFFDEF分布式水文模型耦合进行日径流过程模拟.结果显示:解集产生的日蒸散发能力随时间在平均值附近波动变化,能很好地体现日蒸发量的时间变异特点;模拟的日径流过程的精度较高,平均Nash效率系数在80%以上,径流深相对误差都在10%以内,平均泊松相关系数为0.912,模拟流量过程曲线与实测值匹配的较好;经与采用平均解集模式的模拟结果对比发现,耦合蒸散发时间尺度转换模型后的模拟精度与前者大体相当,部分指标略优于前者.蒸散发时间尺度转换模型解集产生的日蒸散发量序列能够反映日蒸发量的时间变异特点,更能满足区域日降雨径流过程模拟的需要,可为解决资料匮乏区域水文模拟提供一个新途径.  相似文献   

近40年那曲地区气候特征分析   总被引：13，自引：1，他引：12  

毛飞  卢志光  张佳华  郑凌云 《高原气象》2007,26(4):708-715

利用藏北那曲地区6个气象站1961—2000年逐日气象资料,用联合国粮农组织UNFAO(1998年)的Penman—Menteith模式,计算了潜在蒸散量,采用常规统计方法和墨西哥帽小波变换分析了那曲地区1961—2000年气温、降水和潜在蒸散的地理分布以及年内、年际变化规律。研究表明:近40年那曲地区春季、夏季、秋季、冬季、生长季(5~9月)和年的平均气温均呈增加趋势;降水量除夏季外也均呈增加趋势;潜在蒸散量秋季和冬季呈减少趋势,其它时段呈增加趋势,而在1971—2000年,6个不同时段的潜在蒸散量均呈下降趋势。那曲地区近40年来的气候变化比较小,但总体在向暖湿方向发展,2000年以后继续暖湿化的可能性比较大,这有利于当地的农牧业生产和生态环境的改善。  相似文献   

Impact of the spatial resolution on the energy balance components on an open-canopy olive orchard     

《International Journal of Applied Earth Observation and Geoinformation》2019

The recent technical improvements in the sensors used to acquire images from land surfaces has made possible to assess the performance of the energy balance models using unprecedented spatial resolutions. Thus, the objective of this work is to evaluate the response of the different energy balance components obtained from METRIC model as a function of the input pixel size. Very high spatial resolution airborne images (≈50 cm) on three dates over olive orchards were used to aggregate different spatial resolutions, ranging from 5 m to 1 km. This study represents the first time that METRIC model has been run with such high spatial resolution imagery in heterogeneous agricultural systems, evaluating the effects caused by its aggregation into coarser pixel sizes. Net radiation and soil heat flux showed a near insensitive behavior to spatial resolution changes, reflecting that the emissivity and albedo respond linearly to pixel aggregation. However, greater discrepancies were obtained for sensible (up to 17%) and latent (up to 23%) heat fluxes at spatial resolutions coarser than 30 × 30 m due to the aggregation of non-linear components, and to the inclusion of non-agricultural areas in such aggregation. Results obtained confirm the good performance of METRIC model when used with high spatial resolution imagery, whereas they warn of some major errors in crop evapotranspiration estimation when medium or large scales are used.  相似文献