共查询到17条相似文献,搜索用时 312 毫秒
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利用黄河流域90个气象站点实测降水数据,分别从流域和格网两个空间尺度,运用相关分析、相对误差等统计分析方法对TRMM卫星3B43 v7降水数据在黄河流域的精度进行了评估,在此基础上分析了精度评价指标的空间分布特征,讨论高程、降水强度等因素对精度的影响。结果表明:①在流域尺度上,TRMM月降水数据与站点实测月降水数据呈高度线性相关,TRMM降水数据比站点实测降水数据略微偏高。②在格网尺度上,大部分格网的TRMM月降水数据与站点实测月降水数据的相关系数较高,偏差较小。③TRMM降水精度与降水强度、高程相关,TRMM降水量与实测降水量的平均绝对误差呈自东南向西北递减规律,与黄河流域降水分布规律相一致;相对误差、平均误差和平均绝对误差等指标随着高程的增加呈现逐渐减小的趋势。整体上,对于黄河流域,随着降水量的增多,TRMM数据倾向于低估降水量;高海拔区域,TRMM低估降水量,低海拔区域,TRMM高估降水量。通过评估TRMM卫星降水产品在黄河流域的精度,为本地区地面降水产品提供有效补充。 相似文献
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TRMM卫星3B43降水数据在黄河流域的精度分析 总被引:1,自引:0,他引:1
《遥感技术与应用》2019,(5)
利用黄河流域90个气象站点实测降水数据,分别从流域和格网两个空间尺度,运用相关分析、相对误差等统计分析方法对TRMM卫星3B43 v7降水数据在黄河流域的精度进行了评估,在此基础上分析了精度评价指标的空间分布特征,讨论高程、降水强度等因素对精度的影响。结果表明:①在流域尺度上,TRMM月降水数据与站点实测月降水数据呈高度线性相关,TRMM降水数据比站点实测降水数据略微偏高。②在格网尺度上,大部分格网的TRMM月降水数据与站点实测月降水数据的相关系数较高,偏差较小。③TRMM降水精度与降水强度、高程相关,TRMM降水量与实测降水量的平均绝对误差呈自东南向西北递减规律,与黄河流域降水分布规律相一致;相对误差、平均误差和平均绝对误差等指标随着高程的增加呈现逐渐减小的趋势。整体上,对于黄河流域,随着降水量的增多,TRMM数据倾向于低估降水量;高海拔区域,TRMM低估降水量,低海拔区域,TRMM高估降水量。通过评估TRMM卫星降水产品在黄河流域的精度,为本地区地面降水产品提供有效补充。 相似文献
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遥感降水数据精度检验策略及检验方法综述 总被引:1,自引:0,他引:1
卫星遥感反演降水技术为获取全球降水信息提供了途径。遥感降水数据不可避免地存在误差,精度检验是必不可缺的。首先回顾了遥感降水数据全球检验项目;总结检验策略,分为降水事件检验、中小区域尺度检验和大区域尺度检验;然后总结检验方法,包括基于地面观测数据检验方法和基于降水产品检验方法;最后介绍遥感降水数据检验常用流程,包括获取参照数据、检验区域选择和数据对比。遥感降水产品精度检验框架主要存在3个方面的问题,全球遥感降水产品检验策略不完善、参照数据缺乏统一标准和检验指标不统一。未来发展方向可能有完善检验策略、统一参照数据及检验方法。 相似文献
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IKONOS卫星遥感影像的精度分析 总被引:14,自引:0,他引:14
介绍了对目前最高分辨率的民用卫星(IKONOS)遥感影像精度分析的方法及结果,并介绍和使用了仿射变换、线性纠正、投影变换和多项式变换等常用的6种遥感图像纠正的方法,对试验区的影像进行了实例测试,并对不同方法所产生的残差进行了分析。计算结果表明,IKONOS卫星遥感影像的分辨率约为地面1.000 m±0.010 m;测试分析还表明,对IKONOS卫星遥感影像的纠正以采用仿射变换的方法为最佳,纠正后的IKONOS影像可以直接用于1∶10 000比例尺地形图的测绘。 相似文献
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A statistical spatial downscaling algorithm of TRMM precipitation based on NDVI and DEM in the Qaidam Basin of China 总被引:11,自引:0,他引:11
The availability of precipitation data with high spatial resolution is of fundamental importance in several applications such as hydrology, meteorology and ecology. At present, there are mainly two sources of precipitation estimates: raingauge stations and remote sensing technology. However, a large number of studies demonstrated that traditional point measurements based on raingauge stations cannot reflect the spatial variation of precipitation effectively, especially in ungauged basins. The technology of remote sensing has greatly improved the quality of precipitation observations and produced reasonably high resolution gridded precipitation fields. These products, derived from satellites, have been widely used in various parts of the world. However, when applied to local basins and regions, the spatial resolution of these products is too coarse. In this paper, we present a statistical downscaling algorithm based on the relationships between precipitation and other environmental factors in the Qaidam Basin such as topography and vegetation, which was developed for downscaling the spatial precipitation fields of these remote sensing products. This algorithm is demonstrated with the Tropical Rainfall Measuring Mission (TRMM) 3B43 dataset, the Digital Elevation Model (DEM) from the Shuttle Radar Topography Mission (SRTM) and SPOT VEGETATION. The statistical relationship among precipitation, DEM and Normalized Difference Vegetation Index (NDVI), which is a proxy for vegetation, is variable at different scales; therefore, a multiple linear regression model was established under four different scales (0.25°, 0.50°, 0.75° and 1.00°, respectively). By applying a downscaling methodology, TRMM 3B43 0.25° × 0.25° precipitation fields were downscaled to 1 × 1 km pixel precipitation for each year from 1999 to 2009. On the basis of three criteria, these four downscaled results were compared with each other and the regression model established at the resolution of 0.50° was selected as the final downscaling algorithm in this study. The final downscaled results were validated by applying the observations for a duration of 11 years obtained from six raingauge stations in the Qaidam Basin. These results indicated that the downscaled result effectively captured the trends in inter-annual variability and the magnitude of annual precipitation with the coefficient of determination r2 ranging from 0.72 to 0.96 at six different raingauge stations. 相似文献
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MODIS土地覆盖数据产品精度分析——以黄河源区为例 总被引:3,自引:0,他引:3
MODIS土地覆盖数据产品覆盖广、时间分辨率高,是区域土地覆盖变化监测的重要数据源。本文以中国土地资源分类系统为依据,重新归类黄河源区MODIS土地覆盖数据。利用2000年和2006年黄河源区Land-sat解译数据为参考数据,对相应的MODIS土地覆盖数据,从数量精度和形状一致性两个方面进行精度分析和适用性评价。结果表明:在形状上,加入权重的总体形状一致性皆在69%以上,其中主要地类草地的一致性达到88%以上;在数量上,加入权重的总体面积相对误差在26%以内,误差主要产生在未利用土地等地类。MODIS土地覆盖数据产品在大尺度的土地覆盖监测中仍然有重要的应用价值。 相似文献
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It is a significant way to improve the accuracy of hydrologic simulation in the area having sparse observation sites by using the regional climate model precipitation driving hydrological model.As a result,a critical issue arises,which is how to correct the precipitation data coming from Regional Climate Model (RCM) based on the observation in the hydrology research in cold region.However,no systematic studies have been conducted to compare different precipitation correction methods and evaluate their impact on the hydrologic simulation in the cold region yet.Due to this,two kinds of mainstream regional climate model precipitation correction methods,Quantile Mapping (QM) and the Optimal Interpolation (OI),have been compared and evaluated in Manas River basin between 2004 to 2009.The results show that both methods have their own advantages and disadvantages in statistical significance.The correction result of QM is good in low precipitation value and the average annual precipitation is more reasonable at spatial distribution.But when comes the high precipitation value,the result is not stable.Moreover,the correlation coefficient (R) and Root Mean Square Error(RMSE) doesn’t improve.Compared to R 0.37 and RMSE 2.80 mm/d,the modified R is 0.36 and RMSE is 2.70 mm/d;OI can improve R and RMSE significantly,one increases to 0.85 and the other reduces to1.46 mm/d after the correction.Despite that,OI also has its limitations.It gets more tiny precipitation relative to observation and the improvement of spatial distribution is not obvious.Using precipitation data before and after the correction to drive the hydrological models in a same set of model parameters.The results show that QM improves the simulation slightly,Nash-Sutcliffe efficiency coefficient (NSE) changes from 0.63 to 0.65 compared before,while OI is comparatively better,NSE increases to 0.71.This study is helpful to solve the problem of quality optimization in the preparation of hydrological simulation precipitation data and improve the precision of hydrologic simulation in cold region. 相似文献
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以土壤生态系统为基本单元,在对土壤有机碳、无机碳及相关资料调查分析的基础上结合GIS技术,对三工河流域土壤碳库进行了估算。结果表明三工河流域总碳储量约为11. 18Pg,其中有机碳占48. 54%,约为5. 43Pg,无机碳约占到51. 46%,约为5. 75Pg。 相似文献
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科学数据汇交是科学数据共享的重要数据支撑,在重大科学研究计划中更需要考虑数据的汇交与共享。国家自然科学基金委员会于2010年正式启动了“黑河流域生态-水文过程集成研究”重大研究计划(以下简称“黑河计划”)后,就将黑河计划的数据汇交与管理进行了多次讨论,于2012年推出《黑河计划数据汇交与共享管理条例》(以下简称“管理条例”),由黑河计划数据管理中心负责具体执行。黑河计划数据管理中心基于管理条例,设计并实现了面向黑河计划的科学数据汇交管理系统。回顾了科学数据汇交的发展现状,介绍了管理条例的核心内容,设计了黑河计划数据汇交的技术流程,并将数据提供者的权益保护嵌入到数据服务流程中,并根据黑河计划特点进行数据共享管理。针对数据汇交系统在实现中的关键技术问题进行了讨论,包括集成GeoNetwork系统实现元数据的撰写、以提高数据质量为目标的数据审核、高效的数据服务以及数据的知识挖掘4个方面。 相似文献
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以青山河流域作为研究区域,通过采用ArcGIS结合地理空间水文模型扩展(HEC-GeoHMS)模块,对青山河流域数字高程模型(DEM)数据进行分析,生成数字水系,划分提取子流域。运用AutoCAD根据划分边界在万分之一地形图上量测流域特征值,计算提取成果与量测值相对误差,结果表明,相对误差值在模型计算允许范围以内,结果基本可靠,符合模型计算要求。同时通过统计分析,得出相对误差与流域地形坡度存在一定相关性的结论。通过研究可以确定,相比传统的手工量测,采用HEC-GeoHMS模块,可以使子流域提取与数字水系生成在保证精度的前提下变得更加高效与便捷,并可以为HEC-HMS模型的计算提供数据基础。 相似文献