Geostatistics for assessing the efficiency of a distributed physically‐based water quality model: application to nitrate in the Seine River     

Edwige Polus  Nicolas Flipo  Chantal de Fouquet  Michel Poulin 《水文研究》2011,25(2):217-233

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6种卫星降水产品在中国区域的精度特征评估   总被引：4，自引：2，他引：2  

廖荣伟  张冬斌  沈艳 《气象》2015,41(8):970-979

采用2012—2013年国家气象信息中心2419个国家级地面气象站格点化数据和TRMM(3B40RT、3B41RT、3B42RT)、CMORPH、GSMaP、HYDRO共6种0.25°×0.25°卫星反演降水数据,从中国区域、中国东部区域及中国西部区域3种空间尺度综合验证和比较了日尺度上卫星反演降水产品的精度。结果表明：春、夏、秋季卫星反演降水产品对降水描述的准确性高于冬季。相关性、均方根误差等指标随季节变化明显,且差异较大,夏季每种降水产品的评估指标均优于冬季。不同区域之间定量评估指标差异明显,具有月尺度变化特征。卫星反演降水产品对冬季小降水及固态降水的反演能力有限。对于中国区域的大范围降水事件,每种降水产品可以较好进行再现,但均以多传感器联合后的产品质量较高,单一微波、红外或可见光的效果较差。TRMM的3B42RT在夏季对降水反演的落区较好,但极值偏大,CMORPH的综合评价较好。卫星降水产品精度的空间分布与地形有一定的关系。  相似文献   

热红外遥感地表温度与发射率地面验证进展     

朱金顺  任华忠  叶昕  曾晖  聂婧  蒋晨琛  郭金鑫 《遥感学报》2021,25(8):1538-1566

地表温度与发射率是地表—大气系统长波辐射和潜热通量交换的直接驱动力,是描述区域和全球尺度上地表能量平衡与水平衡的重要参数,其时空变化信息在气象预测、气候变化、水循环、地质勘探、农林监测和城市热环境等诸多领域具有广泛的应用。热红外遥感作为当前获取区域或全球尺度上地表温度和发射率的最有效手段之一,相较于传统的地面点位测量方法,具有空间覆盖范围大和重复观测等优势。对热红外遥感定量反演的地表温度与发射率产品进行地表真实性验证,有利于发现遥感数据自身或其反演算法的缺陷,确定产品的精度与不确定度,便于遥感产品的应用与推广。本文首先回顾了地表温度和发射率的定义,阐述了热红外遥感可反演、地面可测量的地表温度和发射率的科学内涵,并对利用热红外遥感数据反演地表温度和发射率的理论和方法作了概述;对地表温度和发射率地面验证的框架体系、验证指标进行总结,建立了基于精度、精确度、不确定度、完整性和稳定性的验证评价指标体系;总结了地表温度和地表发射率的地面验证方法、地面测量方法、辅助数据的获取方法、地表温度地面测量的采样方法,以及在验证异质非同温地表时从点到像元尺度的地表温度尺度转换方法等,分析了地面验证过程的主要误差来源;归纳了目前地表温度和地表发射率主要验证站点、观测网络及其空间分布特征;最后,本文讨论了地表温度与发射率地面验证存在的若干问题,并对地表温度与发射率验证工作的发展前景和趋势进行了相关展望。  相似文献   

TRMM3B42降雨数据在渭河流域的应用分析   总被引：3，自引：0，他引：3       下载免费PDF全文

赵海根  杨胜天  周旭  王志伟  吴琳娜 《水文》2015,35(1):61-67

运用渭河流域24个气象站点日降雨数据对2001~2012年热带测雨卫星(TRMM)3B42数据在不同子流域、不同降雨强度以及不同时间尺度的精度进行了对比验证,并对比分析了基于TRMM和站点数据的渭河流域降雨时空分布特征。结果显示:在不同子流域的日TRMM数据比站点观测数据对低值降雨更为敏感,而在极大值降雨数据观测上两者差距较大,月尺度TRMM站点观测数据确定性系数在0.89到0.96之间;两种数据在流域降雨的时空分布上表现一致性,在年内6月中旬~10月初为湿润多雨期,其余月份降雨较少,空间分布呈东南部大,西北部小的格局。  相似文献   

CCD卫星相机时间序列定标:以CBERS02B为例     

高海亮  顾行发  余涛  李小英  巩慧  李家国 《测绘学报》2011,40(2):180-187

采用沙漠场景法、稳定目标法和交叉定标法对CBERS02B星的CCD相机开展时间序列定标,分别得到CCD相机2007-2008年期间三种方法对应的定标系数,并同CBERS02B卫星官方提供的定标系数进行比对.结果表明,三种方法得到的定标系数其误差均小于10%,不同方法的结果具有较好的一致性.最后,分析总结各种时间序列定标...  相似文献   

Validation of a TRMM-based global Flood Detection System in Bangladesh     

Caitlin Balthrop Moffitt  Faisal Hossain  Robert F. Adler  Koray K. Yilmaz  Harold F. Pierce 《International Journal of Applied Earth Observation and Geoinformation》2011

Although the TRMM-based Flood Detection System (FDS) has been in operation in near real-time since 2006, the flood ‘detection’ capability has been validated mostly against qualitative reports in news papers and other types of media. In this study, a more quantitative validation of the FDS over Bangladesh against in situ measurements is presented. Using measured stream flow and rainfall data, the study analyzed the flood detection capability from space for three very distinct river systems in Bangladesh: (1) Ganges– a snowmelt-fed river regulated by upstream India, (2) Brahmaputra – a snow-fed river that is braided, and (3) Meghna – a rain-fed and relatively flashier river. The quantitative assessment showed that the effectiveness of the TRMM-based FDS can vary as a function of season and drainage basin characteristics. Overall, the study showed that the TRMM-based FDS has great potential for flood prone countries like Bangladesh that are faced with tremendous hurdles in transboundary flood management. The system had a high probability of detection overall, but produced increased false alarms during the monsoon period and in regulated basins (Ganges), undermining the credibility of the FDS flood warnings for these situations. For this reason, FDS users are cautioned to verify FDS estimates during the monsoon period and for regulated rivers before implementing flood management practices. Planned improvements by FDS developers involving physically-based hydrologic modeling should transform the system into a more accurate tool for near real-time decision making on flood management for ungauged river basins of the world.  相似文献   

A GCM-Based Forecasting Model for the Landfall of Tropical Cyclones in China     

SUN Jianqi  Joong Bae AHN 《大气科学进展》2011,28(5):1049-1055

A statistical dynamic model for forecasting Chinese landfall of tropical cyclones (CLTCs) was developed based on the empirical relationship between the observed CLTC variability and the hindcast atmospheric circulations from the Pusan National University coupled general circulation model (PNU-CGCM).In the last 31 years,CLTCs have shown strong year-to-year variability,with a maximum frequency in 1994 and a minimum frequency in 1987.Such features were well forecasted by the model.A cross-validation test showed that the correlation between the observed index and the forecasted CLTC index was high,with a coefficient of 0.71.The relative error percentage (16.3%) and root-mean-square error (1.07) were low.Therefore the coupled model performs well in terms of forecasting CLTCs;the model has potential for dynamic forecasting of landfall of tropical cyclones.  相似文献   

Validation of the Satellite-Derived Rainfall Estimates over the Tibet          下载免费PDF全文

CHU Duo  PUBU Tundrop  NORBU Ghancan  SAGAR Bajrachary  MANDIRA Shresth  GUO Jianping 《Acta Meteorologica Sinica》2011,25(6):734-741

Measuring rainfall from space appears to be the only cost effective and viable means in estimating regional precipitation over the Tibet, and the satellite rainfall products are essential to hydrological and agricultural modeling. A long-standing problem in the meteorological and hydrological studies is that there is only a sparse raingauge network representing the spatial distribution of precipitation and its quantity on small scales over the Tibet. Therefore, satellite derived quantitative precipitation estimates are extremely useful for obtaining rainfall patterns that can be used by hydrological models to produce forecasts of river discharge and to delineate the flood hazard area. In this paper, validation of the US National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC) RFE (rainfall estimate) 2.0 data was made by using daily rainfall observations at 11 weather stations over different climate zones from southeast to northwest of the Tibet during the rainy season from 1 June to 30 September 2005 and 2006. Analysis on the time series of daily rainfall of RFE-CPC and observed data in different climate zones reveals that the mean correlation coefficients between satellite estimated and observed rainfall is 0.74. Only at Pali and Nielamu stations located in the southern brink of the Tibet along the Himalayan Mountains, are the correlation coefficients less than 0.62. In addition, continuous validations show that the RFE performed well in different climate zones, with considerably low mean error (ME) and root mean square error (RMSE) scores except at Nielamu station along the Himalayan range. Likewise, for the dichotomous validation, at most stations over the Tibet, the probability of detection (POD) values is above 73% while the false alarm rate (FAR) is between 1% and 12%. Overall, NOAA CPC RFE 2.0 products performed well in the estimation and monitoring of rainfall over the Tibet and can be used to analyze the precipitation pattern, produce discharge forecast, and delineate the flood hazard area.  相似文献   

AMSR-E土壤湿度产品在锡林浩特草地样区的精度验证   总被引：1，自引：0，他引：1  

陈洁  杨忠东  武胜利 《气象》2011,37(3):334-338

AMSR-E土壤湿度产品已逐渐应用于气象,农业等各个领域,对土壤湿度的研究,特别是干旱半干旱地区,有着重要的科研和现实意义.为了验证AMSR-E土壤湿度产品在锡林浩特草地的适用性,利用锡林浩特草地野外实验,在3 km×3km范围内,与同经纬度地面9个点的2 cm土壤体积含水量数据作产品精度验证.通过与降水量的比较,验证了AMSR-E土壤湿度产品的可靠性,通过与地面实测值的比较,验证结果表明,AMSR-E反演的平均土壤体积含水量与地面实测平均土壤体积含水量分别为13.3%和11.8%,两者土壤体积含水量的RMSE为3.7%.  相似文献   

基于反相C₈色谱柱的海洋浮游藻色素高效液相色谱分析方法有效性验证     

邓春梅  姚鹏  于志刚  牛增元 《中国海洋大学学报(自然科学版)》2011,(Z1):272-278

对一种海洋浮游藻色素高效液相色谱分析方法进行了有效性验证。该方法使用反相C8色谱柱,以甲醇、乙腈和丙酮为流动相,并在流动相中添加吡啶/醋酸溶液作为修饰剂改善色素峰的分离效果。结果表明,4种色素标准在一定的浓度范围内线性关系良好,叶绿素a的线性范围为189.6~18 960μg/L,叶绿素b为89.2~8 920μg/L,β,β-胡萝卜素为7.77~777.2μg/L,叶黄素为15.28~1 528μg/L。除β,β-胡萝卜素外各色素标准的回收率在不同浓度下均在90%以上,相对标准偏差也普遍低于5%。在4个参考藻种和123个胶州湾现场样品中共检测出37种色素,一些关键的特征色素均获得了良好的分离效果。该方法操作简便,具有分离度好、灵敏度高、重复性好、回收率高等优点,适用于培养的藻种和现场样品中的海洋浮游藻色素分析。  相似文献