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1.
ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅｔｈｅｅａｒｌｙ 1 970ｓ,ｔｈｅＡｄｖａｎｃｅｄＶｅｒｙＨｉｇｈＲｅｓｏｌｕｔｉｏｎＲａｄｉｏｍｅｔｅｒ(ＡＶＨＲＲ)ｏｎｂｏａｒｄｔｈｅＮａｔｉｏｎａｌＯｃｅａｎｉｃａｎｄＡｔｍｏｓｐｈｅｒｉｃＡｄｍｉｎｉｓｔｒａｔｉｏｎ (ＮＯＡＡ)ｓｅｒｉｅｓｏｆＰｏｌａｒ ｏｒｂｉｔｉｎｇＯｐｅｒａｔｉｏｎａｌＥｎ ｖｉｒｏｎｍｅｎｔａｌＳａｔｅｌｌｉｔｅｓ (ＰＯＥＳ)ｈａｓｂｅｅｎｕｓｅｄｆｏｒｓｅａｓｕｒｆａｃｅｔｅｍｐｅｒａｔｕｒｅ (ＳＳＴ)ｒｅｔｒｉｅｖａｌａｎｄｃｌｏｕ…  相似文献   

2.
叶面积指数是描述土壤-植被-大气之间物质和能量交换的关键参数,获取大区域长时间序列叶面积指数有助于研究气候变化条件下植被的响应及反馈。本文利用MODIS观测和经过重新处理的地表长时间数据集（Land Long Term Data Record）LTDR AVHRR数据,生成了全球1981-2012年叶面积指数数据。算法通过建立二者之间像元级关系,利用高质量MODIS观测约束历史AVHRR数据的反演,这有助于减小2种存在显著差别传感器反演结果的不一致性,也有助于提高AVHRR反演质量。首先算法利用高质量MODIS地表反射率反演2000-2012年叶面积指数,然后利用多年每8 d的LTDR AVHRR地表反射率数据计算简单比植被指数（Simple Ratio,SR）,利用SR平均值和MODIS LAI平均值建立像元级AVHRR SR-MODIS LAI关系。在此基础上,实现1981-1999年AVHRR LAI反演,最终得到全球1981-2012年叶面积指数数据。本算法反演的AVHRR和MODIS LAI与全球植被的空间分布吻合,能表征主要生物群系类型的季节变化特征,2个数据集一致性较好,并且与NASA MODIS LAI标准产品（MOD15A2）的空间分布和季节变化曲线吻合较好。  相似文献   

3.
Daily and ten-day Normalized Difference Vegetation Index(NDVI) of crops were retrieved from meteorological statellite NOAA AVHRR images ,The temporal variations of the NDVI were analyzed during the whole growing season,and thus the principle of the interaction between NDIV profile and the growing status of crops was discussed,As a case in point,the relationship between integral NDVI and winter wheat yield of Henan Province in 1999 had been analyzed.By putting integral NDVI values of 60 sample counties into the winter wheat yield-integral NDVI coordination,scattering map was plotted. It demonstrated that integral NDVI had a close relation with winter wheat yield.These relation could be described with linear,cubic polynomial ,and exponential regression,and the cubic polynomial regression was the best way,In general ,NDVI reflects growing status of green vegetation ,so crop monitoring and crop yield estimation could be realized by using remote sensing technique on the basis of time serial NDVI data together with agriculture calendars.  相似文献   

4.
In this study, we measured the droplet size distribution(DSD) and visibility of sea fog using a fog droplet spectrometer and visibility meter, respectively, during the July 23-August 3 and August 22-September 13 periods of the 2016 Chinese National Arctic Research Expedition. We calculated the visibility using the Mie theory and the DSD data and then compared the calculated with the observed visibility. The comparison shows that the deviations in the calculated visibility caused by DSD data sampling errors cannot be ignored. During navigation, wind and ship speeds tended to push or pull the sampled air and cause turbulence pulsation, which influenced the sampling of the fog droplet spectrometer. This influence is weak when the liquid water content(LWC) is high but becomes stronger as the LWC decreases. Taking the sailing speed and heading into consideration, the wind speed component parallel and perpendicular to the air inlet of the fog droplet spectrometer exhibit different laws in the deviation. By performing a fitting analysis of the calculated and observed visibilities under different wind speeds and wind directions, here, we present two sets of correction coefficients for the two wind-speed components and a method for correcting the calculated visibility. This correction method shows excellent results.  相似文献   

5.
气溶胶光学厚度作为描述气溶胶光学特性的重要参数之一, 被广泛应用于空气质量监测及辐射传输模型的大气订正等研究中。卫星遥感可快速反演获取大范围气溶胶信息, 但其产品通常因云覆盖或暗目标算法等原因而存在空间覆盖率较低的问题, 且产品时相受限于卫星过境时间。水平能见度作为描述气溶胶光学特性的另一重要参数, 由分布广泛的气象台站一日8 次固定时间多次发布。建立水平能见度与气溶胶光学厚度的转换关系, 可实现对卫星反演气溶胶光学厚度的有益补充。本文利用2001-2009 年的MODIS气溶胶光学厚度产品与中国华东地区71 个气象台站的水平能见度数据, 对描述两者转换关系的Peterson 模型进行区域优化。采用分区域高斯曲线拟合的方法, 对影响转换精度的主要参数气溶胶标高随时间变化规律开展研究和模拟。利用2010 年数据对优化模型进行精度及区域适用性验证。结果表明, 优化后模型的气溶胶光学厚度估算均方根误差为0.31, 低于原模型误差;精度基本上与单站点优化模型一致, 但在实用性方面优于单站点优化模型。  相似文献   

6.
同其他卫星相比,NOAA卫星搭载的AVHRR积雪产品,具有长达10 a的长时间序列数据集,能够应用于长时间、较大区域范围的积雪覆盖变化分析。由于不同卫星使用的反演算法,波谱宽度和大气订正等不完全相同,故需对不同卫星积雪产品数据集进行一致性检验,将卫星积雪产品更好地应用于气候分析研究。本文采用一种新的评估方法,对空间分辨率为0.05o×0.05o的AVHRR积雪产品与IMS和MOD10A1积雪产品,分别在空间和时间变化上进行对比分析,对AVHRR积雪产品数据集进行检验,发现AVHRR与MODIS积雪产品具有较好的一致性。  相似文献   

7.
本文以NOAA-18(N)AVHRR/3数据,运用通用劈窗技术获得地表温度。首先,利用MODTRAN 4模拟不同地表和大气状况下热红外通道(Ch4,10.3~11.3μm和Ch5,11.5~12.5μm)的星上亮温,并建立模拟数据库。其次,按照地表温度、大气可降水汽含量、地表比辐射率和观测天顶角,对模拟数据库分组,确定出各分组的通用劈窗算法系数。然后,将构建的地表温度反演模型应用到NOAA-18(N)AVHRR/3数据,模型所需的地表比辐射率由NDVI阈值法确定,大气可降水汽含量是利用Li等(2003)提出的一种劈窗的协方差与方差比的方法来估算。反演结果表明:在观测天顶角小于30°或者大气可降水汽含量小于3.5 g/cm2时,地表温度反演的均方根误差小于1.0K;在观测天顶角小于45°并且大气可降水汽含量小于5.5g/cm2情况下,均方根误差小于1.5K。最后,利用美国通量站的实测数据对地表温度反演结果进行了验证,结果表明均方根误差小于1.8K。  相似文献   

8.
运用ＮＯＡＡ卫星的ＡＶＨＲＲ资料，经过大气的水汽订正来反演地面温度，并对哀牢山东西坡逆温的强度和厚度进行分析。结果表明用ＮＯＡＡ资料来解译山区逆温的方法是可行的。  相似文献   

9.
大气水汽含量是遥感定量反演的重要参数。本文利用CE-318太阳光度计,反演了2014年6月至2016年5月南宁市的大气水汽含量,分析其季节变化特征,并将其与探空数据、MODIS近红外水汽产品数据进行相关性分析。结果表明：（1）南宁市大气水汽含量季节变化特征明显：夏季高达4~6 g/cm2,而冬季则只有2 g/cm2,与南宁地处亚热带地区有关。夏季该地区季风气候盛行,大气水汽含量高,冬季季风气候减弱,大气相对干燥。（2）CE-318太阳光度计反演的大气水汽含量（PW）与探空数据获取的水汽含量之间存在良好的线性相关,相关系数为0.877,平均绝对误差为0.42 g/cm2,平均相对误差为10.96%;而MODIS近红外波段反演的水汽精度较低,平均绝对误差为0.74 g/cm2,平均相对误差为18.74%。  相似文献   

10.
OLCI（Ocean Land Colour Instrument）作为MERIS（Medium Resolution Imaging Spectrometer）的后继升级版传感器,在气溶胶反演中存在潜在优势,但是目前利用OLCI数据进行气溶胶监测的研究较少。因此,本文针对OLCI多通道反射特征开发了OLCI云检测算法,并对传统查找表构建方法进行改进,根据观测几何特征提出动态查找表法,并通过光谱卷积方式等效转换MODIS和OLCI红蓝通道地表反射率并获取OLCI红蓝通道地表反射率固定关系,进而实现台湾岛550 nm处的AOD反演。与550 nm处AERONET level 2.0 AOD验证结果首先表明不同季节、不同站点的精度表现存在一定差异,其次相对于同期MOD04_3K AOD产品,本文反演结果与全球气溶胶自动观测网（AERONET）站点实测值之间表现出更显著 的相关性（R2=0.8199）,均方根误差（RMSE）从0.175下降到0.113,相对平均误差（RME）从33.6%下降到26.7%,且67.5%的OLCI AOD落在预测误差（EE）区间内,明显大于MOD04_3K AOD落在预测误差区间的百分比（55.7%）。此外,误差分析表明,当实际AOD值较低时,红蓝通道地表反射率之间关系的误判会导致较为明显的AOD反演相对误差。  相似文献   

11.
We explored the potential of the environment and disaster monitoring and forecasting small satellite constellations (HJ-1A/1B satellites) charge-coupled device (CCD) imagery (spatial resolution of 30 m, revisit time of 2 days) in the monitoring of total suspended sediment (TSS) concentrations in dynamic water bodies using Poyang Lake, the largest freshwater lake in China, as an example. Field surveys conducted during October 17-26, 2009 showed a wide range of TSS concentration (3-524 mg/L). Atmospheric correction was implemented using the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) module in ENVI with the aid of aerosol information retrieved from concurrent Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) surveys, which worked well at the CCD bands with relatively high reflectance. A practical exponential retrieval algorithm was created between satellite remote sensing reflectance and in-situ measured TSS concentration. The retrieved results for the whole water area matched the in-situ data well at most stations. The retrieval errors may be related to the problem of scale matching and mixed pixel. In three selected subregions of Poyang Lake, the distribution trend of retrieved TSS was consistent with that of the field investigation. It was shown that HJ-1A/1B CCD imagery can be used to estimate TSS concentrations in Poyang Lake over synoptic scales after applying an appropriate atmospheric correction method and retrieval algorithm.  相似文献   

12.
Comparison of two wind algorithms of ENVISAT ASAR at high wind   总被引：1，自引：0，他引：1  
Two wind algorithms of ENVISAT advanced synthetic aperture radar (ASAR), i. e. CMOD4 model from the European Space Agency (ESA) and CMOD IFR2 model from Quilfen et al., are compared in this paper. The wind direction is estimated from orientation of low and linear signatures in the ASAR imagery. The wind direction has inherently a 180° ambiguity since only a single ASAR image is used. The 180° ambiguity is eliminated by using the buoy data from the NOAA (National Oceanic and Atmospheric Administration) buoys moored in the Pacific. Wind speed is obtained with the two wind algorithms using both estimated wind direction and normalized radar cross section (NRCS). The retrieved wind results agree well with the data from Quikscat. The root mean square error (RMSE) of wind direction is 2.80? The RMSEs of wind speed from CMOD4 model and CMOD_IFR2 model are 1.09 m/s and 0.60 m/s, respectively. The results indicate that the CMOD_IFR2 model is slight better than CMOD4 model at high wind.  相似文献   

13.
1998-2002年中国地表太阳辐射的时空变化分析   总被引：2，自引：0，他引：2  
地表太阳辐射是陆气能量交换过程中重要的物理参数和生态参数,利用卫星数据反演地表太阳辐射对于全面认识地表太阳辐射空间差异性和年际变化特征具有重要的意义。本文利用GMS-5静止气象卫星数据反演了中国区域1998-2002年地表太阳辐射值,在此基础上分析了我国地表太阳辐射的时空分布特征。结果表明:(1)青藏高原的地表太阳辐射最大,川黔地区最小,都位于北纬22~35°这一带除川黔地区外,地表太阳辐射从东向西增强,西部随纬度升高而减小,东部以长江流域最小,向南北增加,西南最大,北部次之,至东北地区随纬度升高而减小(2)各月地表太阳辐射量分布复杂,最小值都出现在12月,但最大值出现时间受雨季影响很大,珠江、长江一带主要在雨季过后的7月,华北、东北和青藏高原主要出现在雨季前的6月及5月,西南地区则在季风雨季前的4-5月(3)5年来东部沿海地区地表太阳辐射增加了13.71%(+4.37W/m2·a),西藏高原地区地表太阳辐射减少了9.31%(-3.47W/m2·a),全国地表太阳辐射平均减少了0.84%(-0.27W/m2·a)。  相似文献   

14.

Satellite measurements of global sea surface temperatures (SST) have been made since 1982 using the multi-channel radiometers (AVHRR) on NOAA polar orbiting satellites. A four year data set was accumulated at daily intervals and a spatial resolution of about 100 kilometers on an interactive computer system. The time lapse evaluation of the data revealed variations of the SST which were related to coastal and equatorial upwelling events as well as to the pronounced equatorial warming associated with the 1982–1983 El Niño. In the present study, satellite time series are used to describe the annual variability of the SST at selected locations along the coast of China, the Yellow Sea, the Sea of Japan and the Equatorial Indian and Pacific Oceans. Further study of the SST off China using higher resolution satellite data are also described.

  相似文献   

15.
Zhang  Minwei  Dong  Qing  Tang  Junwu  Song  Qingjun 《中国海洋湖沼学报》2010,28(6):1316-1322
Remote sensing techniques is used to quantify the total suspended matter concentration (C TSM). In this study, we used remotely sensed data to retrieve the C TSM for the Taihu Lake, China, and developed an atmospheric correction algorithm especially for CBERS-02B CCD data. We simulated the remote sensing reflectance (R rs) of CCD bands using in-situ observations made in a cruise over the Taihu Lake in autumn 2004, from which a retrieval model is established with simulated R rs(830) and measured C TSM. In addition, we applied the atmospheric correction algorithm and retrieval model to process the CCD data over the lake in 2008 and to retrieve the C TSM. The RMS relative error between the C TSM retrieved from MODIS and from the CCD images is about 42.9%, indicating that algorithms described in this paper can be used for the application of CCD data in monitoring the C TSM distribution in the Taihu Lake.  相似文献   

16.
Forest net primary productivity （NPP） is a key parameter for forest monitoring and management. In this study, monthly and annual forest NPP in the northeastern China from 1982 to 2010 were simulated by using Carnegie-Ames-Stanford Approach （CASA） model with normalized difference vegetation index （NDVI） sequences derived from Advanced Very High Resolution Radiometer （AVHRR） Global Invento y Modeling and Mapping Studies （GIMMS） and Terra Moderate Resolution Imaging Spectroradiometer （MODIS） products. To address the problem of data inconsistency between AVHRR and MODIS data, a per-pixel unary linear regres- sion model based on least ~;quares method was developed to derive the monthly NDVI sequences. Results suggest that estimated forest NPP has mean relative error of 18.97% compared to observed NPP from forest inventory. Forest NPP in the northeastern China in- creased significantly during the twenty-nine years. The results of seasonal dynamic show that more clear increasing trend of forest NPP occurred in spring and awmnn. This study also examined the relationship between forest NPP and its driving forces including the climatic and anthropogenic factors. In spring and winter, temperature played the most pivotal role in forest NPR In autumn, precipitation acted as the most importanl factor affecting forest NPP, while solar radiation played the most important role in the summer. Evaportran- spiration had a close correlation with NPP for coniferous forest, mixed coniferous broadleaved forest, and broadleaved deciduous forest. Spatially, forest NPP in the Da Hinggan Mountains was more sensitive to climatic changes than in the other ecological functional re- gions. In addition to climalie change, the degradation and improvement of forests had important effects on forest NPP. Results in this study are helpful for understanding the regional carbon sequestration and can enrich the cases for the monitoring of vegetation during long time series.  相似文献   

17.
【目的】比较分析湛江近海有色溶解有机物(CDOM)的不同反演算法,并将最佳算法应用于卫星遥感数据,了解湛江近海CDOM空间分布。【方法】基于湛江湾及邻近海域的海上观测资料,利用QAA-E、QAA-Dong和QAA-CDOM三种经典半分析算法以及经验算法反演湛江近海CDOM浓度。【结果与结论】QAA-CDOM算法在三种经典半分析算法中精度最高,平均相对误差(MRE)为28.8%,均方根误差(RMSE)为0.07。同时,利用Rrs(665)/Rrs(444)与a_g(440)进行回归分析,建立CDOM反演的经验算法,决定系数为0.65,验证点的MRE为26.5%,RMSE为0.07。将经验算法应用到Sentinel-2卫星数据,得到CDOM反演空间分布图,显示鉴江口CDOM浓度较高,而硇洲岛附近及离岸较远的海域CDOM浓度较低。  相似文献   

18.
Based on the observed surface suspended matter in the East China Sea in February 2007 and June 2015, an empirical model was established using L1 b's band 4 data to retrieve surface suspended matter from the Moderate Resolution Imagine Spectroradiometer Terra imagery. The squared correlation coefficient is 0.8358, and the root mean square error is 0.4285 mg L-1. The model reflects the distribution characteristics of surface suspended matter in the inner shelf of the East China Sea. In this paper, the satellite images of the study area were retrieved in January from 2001 to 2015, and the monthly distribution of surface suspended matter were obtained. The inter-annual distribution of the study area is similar, and the concentration of surface suspended matter is higher near the shore than offshore. A large amount of surface suspended matter is transported southeast under the influence of Zhejiang and Fujian coastal current and Taiwan warm current. Only a small amount of surface suspension can reach the Kuroshio area. The surface suspended matter concentration changes obviously near the estuary because of the effect of differences in the flux of the Yangtze River. Meanwhile, winter monsoon, temperature front, El Ni?o events, and other factors affect the distribution of surface suspended matter in 100 m isobath to coastal water but minimally influence the distribution in 100 m isobath to deep sea.  相似文献   

19.
The greatest advantage of remote sensing over conventional measurements lies in the opportunity to carry out detailed spatio-temporal analysis of land and ocean features on a very frequent basis. This paper analyses the contribution of satellite imagery to atmospheric, geophysical and ocean studies and management in West Africa since the early 1980s.The detailed application of data from optical sensors (e.g. Meteosat,NOAA/AVHRR, SPOT, Landsat TM, etc.)for weather prediction,hydrogeological, landuse/cover and cartographic studies has been acknowledged. However, the use of microwave (e.g. SAR) and optical data for ocean monitoring and studies in the sub-region is still very limited. Even though sufficient remote sensing expertise and infrastructure is perceived in the region, no clearly defined networking or database exists.  相似文献   

20.
The greatest advantage of remote sensing over conventional measurements lies in the opportunity to carry out detailed spatio-temporal analysis of land and ocean features on a very frequent basis. This paper analyses the contribution of satellite imagery to atmospheric, geophysical and ocean studies and management in West Africa since the early 1980s.The detailed application of data from optical sensors (e.g. Meteosat,NOAA/AVHRR, SPOT,L andsat TM, etc.) for weather prediction, hydrogeological, landuse/cover and cartographic studies has been acknowledged. However, the use of microwave (e.g. SAR) and optical data for ocean monitoring and studies in the sub-region is still very limited. Even though sufficient remote sensing expertise and infrastructure is perceived in the region, no clearly defined networking or database exists.  相似文献   

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