共查询到19条相似文献，搜索用时 625 毫秒
1.
利用非线性算法实现了FY-3A/VIRR数据的海洋表面温度SST产品的反演.对2010年的全球船舶站观测数据和FY-3A/VIRR数据建立匹配数据集,选择单月的匹配数据采用多元回归模型计算得到了适用于FY-3A/VIRR数据的非线性海表温度反演算法NLSST的系数,能够实现FY-3A/VIRR数据的高精度SST产品反演.并利用独立于反演算法的双月匹配数据采用最小绝对偏差方法通过线性模型对SST算法的精度进行检验,结果显示白天和夜间的偏差分别为0.05℃和-0.05℃,绝对偏差在0.50℃以下,标准偏差在0.65℃以下.通过文中实现的算法反演了VIRR数据的SST产品,并和MODIS的官方产品进行比较,结果显示两种SST产品具有很高的一致性. 相似文献
2.
国家卫星气象中心FY-3C/VIRR（visible and infrared radiometer,可见光红外扫描辐射计）海表温度产品在云检测产品的基础上,采用多通道MCSST（multichannel SST）算法进行晴空区海温反演。该文详细介绍了海表温度产品算法、产品设计、质量控制及质量检验方法。FY-3C/VIRR海表温度产品包括5 min段原始投影海温和5 km全球等经纬度投影海温。设计逐像元的海温质量标识,将海温像元分为优、良、差3个等级,用户可根据应用目标选择海温的质量等级。与日最优插值海温OISST（optimum interpolation SST）相比,FY-3C/VIRR 2015年1月—2019年12月的5 min段海温质量检验结果表明:质量等级为优的海温,白天和夜间的偏差分别为-0.18℃和-0.06℃,均方根误差分别为0.85℃和0.8℃;白天海温均方根误差有季节性波动,夏季有的月份均方根误差大于1℃（如2015年7月、2016年7月和2019年7月）;在海温回归系数不变的条件下,夜间海温偏差的季节性波动与星上黑体温度相关显著。从一级数据质量、定位、业务运行状况等方面讨论引起海表温度产品异常的原因,为FY-3C/VIRR历史数据定位、定标和产品重处理及用户应用提供重要的参考信息。 相似文献
3.
FY3A/VIRR海面温度业务产品算法改进与质量检验 总被引：2，自引：0，他引：2
针对FY3A/VIRR海面温度(SST)业务产品温度偏低的现状,进行误差原因分析,并对SST产品算法进行了如下改进:采用精度优先原则,以尽可能大的SST覆盖度提高SST反演精度;针对业务SST云污染的现状,构建3×3数据块,并在此基础上进行了SST空间一致性检验;引入气候阈值检验,以进一步剔除异常值。改进后的SST产品,全球日平均SST的覆盖度有所降低,但SST的一致性提高了;算法改进前后全球月平均SST覆盖度基本一致,但改进后云污染的现象得到了抑制。利用分析场日平均OISST对改进后的FY3ASST进行了质量检验,在南北纬70°之间的海域,FY3ASST的全局精度为-0.23±1.74℃,负的偏差说明云和气溶胶的影响仍然存在。改进后的FY3ASST 1.74℃的均方根误差与FY3A VIRR 11μm通道1.6K的定标精度量级相当。 相似文献
4.
风云二号H星(FY-2H)于2018年6月5日成功发射且运行稳定,其上搭载的扫描辐射计(stretched visible and infrared spin scan radiometer,VISSR-2)能够提供高时空分辨率的大气可降水(total precipitable water,TPW)产品。FY-2H VISSR TPW产品在分裂窗算法的基础上,增加了6.9μm通道的方法进行反演。利用2019年无线电探空仪数据集,从产品精度和稳定性两个方面评价了FY-2H TPW产品质量。与2019年1、4、7、10月每月前7天的全球探空数据对比,FY-2H TPW均方根误差为4.92 mm,相关系数达到0.96;相对误差在20%以内,并且白天与夜晚时段数据精度均较高。计算2019年全年FY-2H TPW产品相对探空数据的月均方根误差的标准差是0.68 mm,说明FY-2H TPW产品在检验期内较为稳定。分析合成月平均大气可降水产品,FY-2H TPW能正确反映“一带一路”区域大气可降水的分布情况。综合上述结果FY-2H VISSR TPW产品精度较高且质量稳定,具备投入“一带一路”区域... 相似文献
5.
FY-3B卫星VIRR仪器的向外长波辐射(outgoing long-wave radiation,OLR)产品处理采用与NOAA/AVHRR相同的算法模型,即用窗区通道亮温-通量等效亮度温度的回归关系式计算OLR,但两星的OLR业务产品与目前国际质量最好的云和地球辐射能量系统(cloud and earth’s radiant energy system,CERES)仪器观测OLR产品相比,存在约10 W·m~(-2)的系统负偏差。FY-3B的原因在于OLR反演模式建立过程中红外辐射传输计算软件的精度不够。鉴于此,本文采用美国21世纪开发的逐线辐射传输模型计算软件(LBLRTM),模拟计算了全球2521条大气廓线的大气顶辐射率光谱,在此基础上计算了每条廓线的OLR和FY-3B/VIRR窗区通道亮温,应用最小二乘法统计回归模拟数据,重新建立了由FY-3B/VIRR窗区通道亮温计算OLR的回归关系式及系数。模式应用于FY-3BL1级数据,处理2016年1,3,7和10月的FY-3B逐日全球OLR资料,该资料与AQUA-TERRA卫星的CERES仪器OLR观测产品相比,得到日平均OLR:RMSE=9~15 W·m~(-2),R=0.9834,Bias=-0.3W·m~(-2);月平均OLR:RMSE=4~7W·m~(-2),R=0.9915,Bias=-0.3W·m~(-2),表明改进的模式能处理出无系统偏差的、精度基本与CERES观测相当的OLR产品,尽管单通道反演算法有着固有的模式回归误差。 相似文献
6.
为深入了解FY-2卫星大气可降水量(PW)的反演质量,文章选取2012和2015年地基GPS水汽观测数据,与FY-2的PW反演产品进行了对比分析。结果表明:(1)北京、武汉和海口三站GPS/PW(PW_(GPS))与FY-2/PW(PW_(FY-2))在夏季存在显著正相关,三站的相关系数都达到0.67以上,夏季PW的均方根误差值、月平均偏差绝对值均小于冬季。北京与武汉站PW平均偏差和均方根误差在四季均具有明显日变化特征;(2)当PW_(GPS)20 mm时,北京、武汉、海口和拉萨站FY-2/PW与GPS/PW比较一致,PW偏差均值的绝对值和均方根误差较小,当PW_(GPS)20 mm时,PW偏差均值绝对值和均方根误差随PW_(GPS)值减小而迅速变大。FY-2的PW产品在夏季可以为大部分区域提供高时空分辨率、高精度的大气可降水量,在大气湿度非常低、冬季和夜间条件,反演结果精度有待提高。 相似文献
7.
杨志华 《沙漠与绿洲气象(新疆气象)》2014,8(5):48-52
新疆是我国沙尘天气多发区,但是地面测站稀少,使用卫星遥感监测沙尘天气有非常大的优势。利用国家卫星气象中心开发并向各省推广的SMART业务系统,以FY-3B/VIRR为数据源,采用以人机交互方式分析区域沙尘遥感监测方法。以2012年数据为例,对沙尘天气进行了遥感监测,结果表明FY-3B/VIRR数据可有效提取沙尘天气信息,具有较好的沙尘监测评估业务应用前景。 相似文献
8.
开展卫星反演云量的精度评估是业务应用的基础,也是充分发挥卫星观测效益的前提。利用同类卫星产品EOS Aqua/MODIS云产品,选取2015年6月和12月共80个个例,包括43个白天个例,37个夜间个例。采用交叉比对方法对FY-2G云量产品进行相对偏差分析。结果表明:FY-2G与Aqua/MODIS计算云量总体趋势相当,无论从时间分布（白天和夜间）还是季节分布（6月和12月）上看,FY-2G与Aqua云量相对偏差较为稳定,FY-2G反演云量小于Aqua/MODIS反演云量。匹配个例中FY-2G平均云量为72.81%,Aqua/MODIS平均云量是76.19%,两者相关系数为0.74。两者绝对偏差小于5%的像元比例为72.34%;云量偏差绝对值小于15%的像元比例为79.51%。FY-2G与Aqua/MODIS云量偏差主要来自各自卫星的观测能力与所采用的云检测算法。与具有36个探测通道、星下点最低空间分辨率为0.01°×0.01°的Aqua/MODIS观测数据相比,FY-2G所具有的5通道、星下点最高空间分辨率为0.05°×0.05°的观测数据会出现对云,尤其是破碎云和薄卷云的漏检。两种具有不同时空属性的数据在匹配处理时采用的不同算法也会在比对分析中引入偏差。 相似文献
9.
基于AVHRR和VIRR数据的改进型Becker“分裂窗”地表温度反演算法 总被引：2，自引：0，他引：2
为了将基于NOAA-9/AVHRR数据提出的Becker和Li的“分裂窗”地表温度算法成功地应用于长序列NOAA/AVHRR和FY 3A/VIRR数据的地表温度反演,为气候变化研究提供长序列、高精度、高分辨率的地表温度数据集,从辐射传输方程出发,首先利用MODTRA 4.1模式模拟了多种地表和大气状态下的光谱辐亮度数据,并结合AVHRR和VIRR通道4、5的光谱响应函数建立了温度数据集(TS,T4,T5);然后,基于该数据集采用最小二乘法重新计算了Becker和Li算法中的各参数,提出了一个适用于NOAA/AVHRR和FY-3A/VIRR数据的改进型Becker和Li分裂窗地表温度反演算法;并利用改进型算法对2008年4月27日03时12分(世界时)观测的一景覆盖北京地区的NOAA-17/AVHRR数据进行了地表温度的反演,将反演结果与日本东京大学提供的同地区、同时相的MODIS地表温度产品进行了对比分析.结果表明,两种地表温度产品的相关系数为0.88,均方根偏差(RMSD)为2.1K;在两种地表温度差值图像的频率直方图上有69.6％的像元的值在±2K之内,37％的像元的值在±1K之内. 相似文献
10.
基于公众天气预报预测塑料大棚逐日极端气温 总被引：4，自引：1，他引：3
利用浙江省慈溪市的公众天气预报和草莓大棚内极端气温的观测数据,构建一个以室外日最高气温、最低气温、相对湿度、最大风级、白天和夜间天空状况作为输入变量,棚内日最高气温和日最低气温作为输出变量的BP神经网络预测模型。用以预测草莓大棚室内日最高气温和日最低气温。结果表明,该模型对大棚内日最高气温、日最低气温的训练值和实测值之间的均方根误差分别为4.0℃和1.3℃,绝对误差则分别为3.2℃和1.0℃;日最高气温和日最低气温的预测值和实测值之间的均方根误差分别为3.6℃和1.2℃,绝对误差为3.0℃和1.0℃。该模型数据获取方便,实用性强,模拟精度较高,可以较准确的预测未来温室内的极端气温,为温室管理和调控提供依据。 相似文献
11.
提出一种针对FY-3C搭载的微波辐射成像仪（MWRI）海表温度产品的分段回归偏差订正方法,该方法通过引进气候态海表温度数据,建立与关联实测海表温度相匹配的回归模型,并通过对模型中关联变量的误差分析,选择最优样本进行分段回归,以实现对海表温度数据的重新估计。通过对MWRI海表温度数据的偏差订正试验表明,采用分段回归方法获得的订正结果无论在误差指标的空间分布还是时间序列上,都要明显优于采用传统概率密度函数偏差订正方法的结果。其中,采用概率密度函数方法订正后的海表温度产品误差标准差和均方根误差从订正前的0.9—1.0℃,减小到0.8℃左右,而采用分段回归方法获得相应的订正误差仅为0.6℃左右,订正效果有明显改善。 相似文献
12.
本文介绍一种利用FY-4A成像仪遥感数据和全球预报系统(GFS)资料估算全天空地表长波辐射通量的反演方法。该方法通过辐射传输模拟和统计回归计算建立云天地表下行长波辐射通量的反演模式,并基于GFS资料处理云覆盖地区的地表上、下行长波辐射通量。这种全天空状况下两种通量的反演结合了FY-4A晴空地表长波辐射业务产品和本文反演模式处理的云天地表上、下行长波辐射通量。2018年9月1日的处理结果与Aqua/CERES同类产品相对比,精度为:RMSE=20.52 W·m^-2,R=0.9481,Bias=3.3 W·m^-2(夜间地表下行辐射通量对比);RMSE=25.58 W·m^-2,R=0.9096,Bias=5.4 W·m^-2(白天地表下行辐射通量对比);RMSE=10.97 W·m^-2,R=0.9762,Bias=-3.3 W·m^-2(夜间地表上行辐射通量对比);RMSE=19.97 W·m^-2,R=0.9283,Bias=5.0 W·m^-2(白天地表上行辐射通量对比)。这些结果表明本文发展的方法能够反演出精度较好的云天上下行长波辐射通量资料,为今后利用FY-4后续星处理生成全天空状况下的地表长波辐射通量产品奠定了理论基础。 相似文献
13.
The Visible and Infrared Spin-Scan Radiometer(VISSR) onboard the Fengyun-2(FY-2) satellite can provide valuable thermal infrared observations to help create a precipitable water vapor(PWV) product with high spatial and temporal resolutions. The current FY-2/VISSR PWV product in operation is produced by using a traditional two-band physical split-window(PSW) method, which produces low quality results under dry atmospheric conditions. Based on the sensitivity characteristics of FY-2 F/VISSR water vapor channel and two split-window channels to atmospheric water vapor, this study developed a new, robust operational PWV retrieval algorithm for FY-2 F to improve the operational precision of the current PWV product. The algorithm uses a modified three-band PSW method, which adds a scale for the water vapor channel in the improved three-band PSW method. Integrated PWV products from the radiosonde data in 2016 are used here to validate the precision of the PWV retrieved by the modified three-band and traditional two-band PSW methods. The mean bias, root mean square error(RMSE), and correlation coefficient of the PWV retrieved by the modified three-band PSW method are 0.28 mm, 4.53 mm, and 0.969, respectively. The accuracy is much better than the PWV retrieved by the two-band method, whose mean bias, RMSE, and correlation coefficient are 12.67 mm, 29.35 mm, and 0.23. Especially, in mid-or high-latitude regions, the RMSE of the PWV is improved from 10 to 2 mm by changing the inversion in the two-band method to the modified three-band PSW method. Furthermore, the modified three-band PSW results show a better consistency with the radiosonde PWV at any zonal belt and season than the two-band PSW results. This new algorithm could significantly improve the quality of the current FY-2 F/VISSR PWV product, especially at sites where the actual PWV are lower than 15 mm. 相似文献
14.
采用FY-3A/VIRR数据,利用Becker局地分裂窗改进算法反演得到逐日陆表温度 (LST), 对2009年一次高温天气过程进行动态监测, 并分析不同下垫面的热环境变化。结果显示:此过程中可见光红外扫描辐射计 (VIRR) 陆表温度产品在敦煌辐射校正场地两次验证的误差为-0.17 K和1.77 K,与同时间过境的MODIS产品均方根误差为2.64 K,直方图对比陆表温度的频数分布基本一致;对高温天气过程监测发现,此次出现以华北的石家庄、郑州、北京等地和西北地区东部的西安等地为中心的两个陆表温度高值区, 部分地区达到了320.2 K以上;城市剖面资料证实城市热岛现象存在,并发现工矿用地的热岛效应不容忽视,主要是大面积的工矿用地周围植被破坏严重,地表增温更为显著。 相似文献
15.
Satellite retrieval of atmospheric water vapor is intended to further understand the role played by the energy and water cycle to determine the Earth's weather and climate. The algorithm for operational retrieval of total precipitable water (TPW) from the visible and infrared radiometer (VIRR) onboard Fengyun 3A (FY-3A) employs a split window technique for clear sky radiances over land and oceans during both day and night. The retrieved TPW is compared with that from the moderate resolution imaging spectroradiometer (MODIS) onboard the Terra satellite and data from radiosonde observations (RAOB). During the study period, comparisons show that the FY-3A TPW is in general agreement with the gradients and distributions from the Terra TPW. Their zonal mean difference over East Asia is smaller in the daytime than at night, and the main difference occurs in the complex terrain at mid latitude near 30°N. Compared with RAOB, the zonal FY-3A and the Terra TPW have a moist bias at low latitudes and a dry-bias at mid and high latitudes; in addition, the FY-3A TPW performs slightly better in zonal mean biases and the diurnal cycle. The temporal variation of the FY-3A and the Terra TPW generally fits the RAOB TPW with the FY-3A TPW. The FY-3A TPW is more accurate at night, while the Terra TPW is more accurate during the daytime. Comparisons of correlations, root mean square differences and standard deviations indicate that the FY-3A TPW series is more consistent with the RAOB TPW at selected stations. As a result, the FY-3A TPW has some advantages over East Asia in both spatial and temporal dimensions. 相似文献
16.
海表温度是研究海洋表面海气相互作用的一个至关重要的物理参数。为建立长时间序列海表温度数据集,在海表温度反演模型建立过程中还需要考虑卫星之间的差异、卫星仪器随时间的衰减、所采用反演算法模型建立过程中人的主观因素的影响等。为此,针对1989—2008年间NOAA/AVHRR数据特点,发展了统一的海表温度反演模型,并生成了20年时间序列海表温度数据集,空间分辨率达到1km。利用船舶浮标资料和OISST数据对该数据集进行了验证,验证结果表明该数据集均方根误差在1℃左右。最后针对1997/1998年厄尔尼诺事件,用反演的海表温度分析了西太平洋暖池区海表温度距平对这次事件的响应。 相似文献
17.
A Modified Becker''s Split-Window Approach for Retrieving Land Surface Temperature from AVHRR and VIRR 总被引：1，自引：0，他引：1 
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下载免费PDF全文 QUAN Weijun CHEN Hongbin HAN Xiuzhen LIU Yonghong YE Caihua 《Acta Meteorologica Sinica》2012,26(2):229-240
In order to provide a long time-series, high spatial resolution, and high accuracy dataset of land surface
temperature (LST) for climatic change research, a modified Becker and Li's split-window approach is pro-
posed in this paper to retrieve LST from the measurements of Advanced Very High Resolution Radiometer
(AVHRR) onboard National Oceanic and Atmospheric Administration (NOAA)-7 to -18 and the Visible and
InfraRed Radiometer (VIRR) onboard FY-3A. For this purpose, the Moderate Resolution Transmittance
Model (MODTRAN) 4.1 was first employed to compute the spectral radiance at the top of atmosphere
(TOA) under a variety of surface and atmosphere conditions. Then, a temperature dataset consists of
boundary temperature Ts (which is one of the input parameters to MODTRAN), and channels 4 and 5
brightness temperatures (T4 and T5) were constructed. Note that channels 4 and 5 brightness tempera-
tures were simulated from the MODTRAN output spectral radiance by convolving them with the spectral
response functions (SRFs) of channels 4 and 5 of AVHRRs and VIRR. The coefficients of modified Becker
and Li's split-window approach for various AVHRRs and VIRR were subsequently regressed based on this
temperature dataset using the least square method. As an example of validation, one AVHRR satellite image
over Beijing acquired at 0312 UTC 27 April 2008 by AVHRR onboard NOAA-17 was selected to retrieve
the LST image using the modified Becker and Li's approach. The comparison between this LST image and
that from the MODIS level-2 LST product provided by the University of Tokyo in Japan indicates that
the correlation coefficient is 0.88, the bias is 0.6 K, and the root mean square deviation (RMSD) is 2.1 K.
Furthermore, about 70% and 37% pixels in the LST difference image, which is the result of retrieved LST
image from AVHRR minus the corresponding MODIS LST image, have the values within ±2 and ±1 K,
respectively. 相似文献
18.
Mee-Ja Kim Mi-Lim Ou Eun-Ha Sohn Yoonjae Kim 《Asia-Pacific Journal of Atmospheric Sciences》2011,47(5):421-427
Multi-channel sea surface temperature (MCSST) data were retrieved from the Japanese geostationary satellite, MTSAT-1R, for East Asia in western North Pacific. The coefficients used to calculate the MCSST data were estimated by assuming a linear relationship between the brightness temperatures obtained from the satellite and the in-situ buoy SST. It is important to remove cloud contamination pixels to retrieve meaningful information from infrared data. Therefore, the cloud detection algorithm was improved by using a 10-day maximum or minimum composite map for infrared and visible channels. The RMSE of the MCSST in comparison with the two-year buoy SST was about 0.89oC. The error was the largest at mid-latitudes in summer. Additionally, the error between the two SSTs showed that diurnal variation had a positive bias during daytime and a negative bias during nighttime. Furthermore, in 2007, both SSTs showed seasonal and spatial diurnal variation. The magnitude of the daily variation in the MCSST was two times larger than that in the buoy SST, and this was attributed to diurnal heating with a weak surface wind speed. 相似文献
19.
Evaluation and Preprocess of Chinese Fengyun-3A Sea Surface Temperature Experimental Product for Data Assimilation 总被引：1，自引：0，他引：1 下载免费PDF全文
下载免费PDF全文 Validated satellite-derived sea surface temperatures (SSTs) are widely used for climate monitoring and ocean data assimilation systems. In this study, the Fengyun-3A (FY-3A) SST experimental product is evaluated using Advanced Very High Resolution Radiometer (AVHRR)-merged and in situ SSTs. A comparison of AVHRR-merged SSTs reveals a negative bias of more than 2K in FY-3A SSTs in most of the tropical Pacific and low-latitude Indian and Atlantic Oceans. The error variance of FY-3A SSTs is estimated using three-way error analysis. FY-3A SSTs show regional error variance in global oceans with a maximum error variance of 2.2 K in the Pacific Ocean. In addition, a significant seasonal variation of error variance is present in FY-3A SSTs, which indicates that the quality of FY-3A SST could be improved by adjusting the parameters in the SST retrieval algorithm and by applying regional and seasonal algorithms, particularly in key areas such as the tropical Pacific Ocean. An objective analysis method is used to merge FY-3A SSTs with the drifter buoy data. The errors of FY-3A SSTs are decreased to-0.45K comparing with SST observations from GTSPP. 相似文献