共查询到18条相似文献，搜索用时 15 毫秒
1.
为提高风云三号气象卫星(FY-3)紫外臭氧总量探测仪(TOU)观测数据得到的吸收性气溶胶指数AAI(Absorbing Aerosol Index)或AI(Aerosol Index)的可靠性,需要了解AAI指数与相对湿度之间的内在关系。本研究利用大气辐射传输模型DAK(Doubling-Adding KNMI)分别模拟了在城市气溶胶和乡村气溶胶模式下AAI同相对湿度之间的关系,并将结果同已观测到的实际结果进行对比。结果发现,在相对湿度呈高值时AAI指数出现很大的变化,但相对湿度对两种气溶胶模型的影响具有相反的效应,分析显示当大气中含有吸收性气溶胶如含碳类气溶胶(在中国北部的污染过程中很常见)时,AAI结果对RH(Relative Humidity)有很强的依赖。在应用AAI指数产品检测污染过程中需要注意气溶胶的具体类型和相对湿度的影响,必要时在高相对湿度过程中进行数据校正或剔除。 相似文献
2.
北极臭氧年际变化特征及其与极涡的关系 总被引：2，自引：0，他引：2
利用风云三号卫星搭载的紫外臭氧总量探测仪(TOU)和国际同类卫星的臭氧总量数据对1979年—2011年北半球春季臭氧特征进行了分析,发现北极臭氧年际变化显著,它与平流层温度变化一致(相关系数为0.75)。北极臭氧损耗异常强弱年的月均和日变化特征有明显差异,春季北极臭氧损耗强年有明显的化学损耗过程(1997年和2011年),而弱年化学作用影响不明显(1999年和2010年)。损耗弱年的日变化型在不同年份特征不同,它的臭氧变化可能更多受天气过程的影响。综合分析北极涛动、极涡和平流层温度等大气环流背景场的变化,表明春季北极臭氧损耗强弱受大气环流变化影响。北极涛动指数正位相,极涡偏强偏冷,北极臭氧损耗异常偏高。北极涛动指数负位相,极涡偏弱偏暖,北极臭氧损耗异常偏低。 相似文献
3.
AIRS/TOVS/TOMS反演的臭氧总量的对比分析 总被引：1，自引：0，他引：1
本文利用2003-2005年的AIRS(Atmospheric Infrared Sounder),TOVS(The TIROS Operational Vertical Sounder)和TOMS(Total ozone mapping spectrometer)卫星资料反演的大气臭氧柱总量分析了全球范围内大气臭氧的分布和变化特征.北半球大气臭氧柱总量有明显的季节变化,在春季达到最大值约为322.25DU,秋季达到最小值约为277.83DU,变化幅度约为45DU,南半球季节变化不明显;大气臭氧柱总量有明显的纬度变化,低纬度地区臭氧柱总量较低,基本维持在250-270DU,高纬度地区臭氧柱总量较高,北半球中高纬地区平均约为294DU,南半球中高纬地区平均约为279DU.几种反演结果的对比分析表明,AIRS的全球(60°N-60°S)平均臭氧柱总量的值比TOVS和TOMS的值高大约3-5DU.其反演值在南极大陆和沙漠地区出现异常.与地基观测资料相比较,AIRS和TOMS反演值与地面站观测值之间具有一致的变化趋势,并存在较好的相关性. 相似文献
4.
臭氧已成为中国继PM2.5之后多地的首要污染物,臭氧污染防治是中国“十四五”及未来大气污染防治的重点。本文回顾了近60年来国内外臭氧卫星观测方面的主要进展,包括卫星探测载荷和臭氧相关的反演应用技术等,分为3个阶段总结了卫星载荷天底、临边和掩星3种探测方式的发展历程。臭氧卫星遥感反演算法和监测应用也随着载荷的发展在不断更新,本文重点介绍了臭氧柱总量和垂直廓线卫星遥感反演算法、近地面臭氧及其前体物观测、平流层臭氧入侵观测和区域传输、臭氧卫星观测数据的精度验证等方面的重要进展。对比国际臭氧卫星遥感监测,中国臭氧监测卫星发展滞后,虽然国家民用空间基础设施规划中陆续发射的高光谱观测卫星、大气环境监测卫星具有初步的臭氧监测能力,但在卫星载荷在功能、性能等方面还有不小差距,比如空间分辨率、信噪比等方面。在算法反演和监测应用方面,目前臭氧柱总量反演精度较高,还存在对流层中低层和近地面臭氧浓度反演精度不够,臭氧污染评估及成因分析不足,如近地面臭氧污染迁移转化过程、平流层臭氧侵入识别分析等问题,是下一步要重点关注的方向。 相似文献
5.
太阳光度计反演大气水汽总量的方法与结果对比分析 总被引：2，自引：0，他引：2
详述了使用太阳光度计反演大气水汽柱总量的反演方法—单通道法和双通道法,其中双通道法又可采用不同
的非水汽通道来实现。考虑到气溶胶光学厚度及瑞利散射的影响,分析了不同方法反演所得水汽总量相对探空数据的
误差。结果表明,这些方法的反演结果非常接近。在实际应用中,可使用任一种方法来反演水汽。 相似文献
6.
实用劈窗算法的改进及大气水汽含量对精度影响评价 总被引：2，自引：0，他引：2
对劈窗算法进行了改进,提高了算法的精度和实用性.对影响大气透过率的大气水汽含量进行了敏感性分析.模拟数据结果表明,劈窗算法对大气水汽含量不敏感,当大气水汽含量误差在-80%～80%变化时,反演的平均精度仍能在1 ℃以下.对实际MODIS影像进行反演的结果与大气模拟数据分析的结论基本一致,这说明适当地利用大气水汽含量的先验知识可以提高劈窗算法反演地表温度的精度. 相似文献
7.
大气气溶胶成分的复杂变化导致其在气候变化评估中具有很高的不确定性。气溶胶成分遥感利用遥感观测的气溶胶光学—微物理参数,定量估计整层大气气溶胶主要成分含量,具有实时快速、空间覆盖、保持气溶胶自然状态等特点。本文介绍了近年来气溶胶成分遥感在理论基础和观测研究方面的进展情况。首先,在简要回顾反演算法发展的基础上,以目前较先进的成分遥感分类模型(包括黑碳、棕色碳、沙尘、非吸光有机物、细粒子无机盐、海盐和水)为例,详细分析了气溶胶成分遥感反演的思路。据此提出了基于气溶胶综合光学—微物理特性(包括光学吸收/散射、粒径尺度、形状等敏感性特征参数)的气溶胶成分遥感识别方法。之后,结合气溶胶混合方式,讨论了复折射指数计算方法及其对成分反演的影响,并给出了利用同步化学采样观测验证气溶胶成分遥感的一些结果示例。最后,结合观测手段拓展、成分模型优化、反演精度提升、应用能力推广等4个方向,展望了大气气溶胶成分遥感的发展趋势,及其在全球气候变化评估等领域的应用。 相似文献
8.
大气水分含量的空间异质性及其对地表温度反演的影响 总被引：1，自引：0，他引：1
大气水分含量是影响单波段热红外地表温度反演的关键因素之一。研究大气水分含量空间异质性对地表温度反演的影响误差有助于单波段热红外数据的合理应用。以MODIS MOD 05_L2产品为数据源,探讨区域大气水分含量的空间异质性及其对Landsat地表温度反演的影响。在推导大气水分含量对地表温度反演误差模型的基础上,针对Landsat5热红外波段,结合不同区域的大气水分含量分布状况,对大气水分含量的空间异质性可能引起的地表温度反演误差进行了模拟计算与对比分析。结果显示,大气水分含量空间异质性对地表温度反演的影响与大气水分含量及其异质性程度有关:当大气水分含量的空间异质性相对较大时,误差值和误差范围都比较大,达到0.5~2℃,相对误差为2%~20%;当大气水分含量空间分布较均匀时,误差值和误差范围为0.1~0.2℃,相对误差为0.5%~2%。可见,对于空间异质性程度较大的区域,区域面上大气参数的获得对地表温度的准确反演具有重要意义。 相似文献
9.
地表反射率产品支持的GF-1 PMS气溶胶光学厚度反演及大气校正 总被引：1，自引：0，他引：1
GF-1卫星PMS(GF-1 PMS)数据具有高空间分辨率、短重访周期的特点,可以在地表类型识别、参数提取中发挥重要作用。但由于缺少2.1μm附近的短波红外波段,使得气溶胶反演时地表反射率的精确确定非常困难,从而导致其高精度大气校正难以开展,限制了该数据的应用。本文提出了一种地表反射率数据支持的气溶胶反演方法,用于GF-1PMS数据的大气校正。其基本思想是:使用现有的地表反射率数据集为GF-1PMS数据提供地表反射率,用于确定GF-1PMS图像中浓密植被像元(DDV)的分布,基于确定的浓密植被像元反演气溶胶光学厚度(AOD),并用于大气校正。这里使用的地表反射率数据集为合成的无云MODIS地表反射率产品,对GF-1PMS数据做了空间尺度的转换。为降低两类数据配准误差对地表反射率确定的影响,提出了使用区域NDVI分布百分比匹配的方法,回避了像元的直接匹配,为GF-1PMS数据提供DDV的空间分布。为验证该方法的有效性,利用北京、太湖两个AERONET站点观测的气溶胶光学厚度对气溶胶反演结果进行精度验证,结果表明,气溶胶反演算法精度较高,稳定性较强。AOD反演结果应用于北京和敦煌地区的GF-1PMS数据大气校正,获得的地表反射率与地面实测的地表反射率的误差低于0.015,且大气校正后影像对比度明显提高。 相似文献
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11.
M. B. Potdar 《Journal of the Indian Society of Remote Sensing》1990,18(4):65-75
A model (named ATMRAD) of radiation transfer in the Earth’s hazy atmosphere based on simplistic solution of radiation transfer equation and tropical model atmosphere is developed to estimate path radiance for correction of remote sensing multispectral data. The atmosphere is assumed to be cloud free and plane-parallel stratified with various quatities specified for 46 layers in its 100 km assumed thickness and model altitude profiles of haze aerosols specified for 23 km and 5 km visibility ranges. Altitude profiles of haze for any intermediate visibility ranges are deduced from linear mixing of the two profiles for 23 and 5 km visibilities. Deirmendjian size distribution function is assumed for aerosols. The radiation transfer calculations have been performed for 126 wavelengths in 0.25 to 3.0 μm range by considering Rayleigh and Mie Scatterings by air molecules and aerosols; and absorption by atmospheric gases. The model calculations have been carried out for path radiances in bands of IRS LISS-I sensor for different visibility ranges and solar illumination angles. 相似文献
12.
AbstractThe impact of Brown Carbon (BrC) to aerosol light absorption has been paid more attention recently and there are a large number of studies showing that the influence of BrC on radiative forcing should not be ignored. BrC also acts as an important component of haze pollution which is occurring frequently in Wuhan, China. Therefore, it is essential to estimate their optical properties, composition, and mass concentration. Considering most haze pollution happens during the coldest time, we retrieved BrC columnar content during winter in Wuhan for the first time. Our method bases on the fact that BrC showed the strong spectral dependence on UV-light absorption. Using this method, we found that BrC makes up the small proportions of total aerosol volume (less than 10%). In the winter of 2011, we retrieved the daily-averaged columnar-integrated mass concentration of BrC on clear day is 4.353 mg/m2 while that of haze day is 12.750 mg/m2. According to the sensitivity study, we found that the results highly relied on the assumed aerosol refractive index. To reduce the uncertainty of this approach, we need to gain a better understanding of the temporal variability of the radiation absorbing components of these aerosols in the future. 相似文献
13.
Pui-King Chan Bo-Cai Gao 《Geoscience and Remote Sensing Letters, IEEE》2005,2(3):270-274
The monthly average sea surface temperature (SST) datasets of MODIS (Moderate Resolution Imaging Spectroradiometer), NCEP (National Center for Environmental Prediction) and TMI (Tropical Rainfall Measuring Mission (TRMM) Microwave Imager) are compared for the period March 2000 to June 2003. Large discrepancies (0.5 K->1 K) are found over extensive areas: the tropical Atlantic, tropical western Pacific, Bay of Bengal, Arabian Sea and the storm tracks. Many of these discrepancies are related to the biases inherent in the infrared and microwave retrieval methods. Probable causes for these biases include cirrus contamination, insufficient corrections for water vapor absorption and aerosol attenuation in infrared retrieval as well as uncertainty in surface emissivity in microwave retrieval. The SST difference patterns bear close resemblance to the patterns of distribution of aerosols, cirrus, atmospheric water vapor and surface wind speed at certain regions. Correlations between SST difference and aerosol optical depth, column water vapor and surface wind speed in some areas are high (>0.75). These biases have to be adjusted in order for the SST datasets to be more useful for climate studies. 相似文献
14.
《地理信息系统科学与遥感》2013,50(5):735-754
Many environmental factors, such as stratospheric ozone, aerosols, and clouds, may affect ultraviolet (UV) irradiance. The aim of this study is to investigate the possible association between ultraviolet B (UVB) radiation and total cloud amount, ozone, and aerosols simultaneously, leading to the assessment of possible impacts of climate change on UVB flux variations in the continental United States (U.S.). Spatiotemporal correlation analyses were conducted, based on data collected from the Total Ozone Mapping Spectrometer (TOMS) and the International Satellite Cloud Climatology Project (ISCCP), with a geographic information system (GIS). Findings indicate that in the past 22 years, while ozone decreased and aerosols increased across the U.S., the UVB decrease in the northern states was consistent with an increase in aerosols and total cloud amount. Therefore, to some extent, the trend characteristics of UVB over the U.S. between 1980 and 2002 were simultaneously affected by such dominant factors as total ozone and by such auxiliary factors as aerosol and total cloud amount. Climate change impact resulting in higher total cloud amount in the northern states might result in lower UVB in the future. 相似文献
15.
提出基于MODIS大气和地表产品反演高精度复杂地形下的光合有效辐射模型。该方法是对普通的大气传输模型进行简化, 在模型中分别考虑了削减光合有效辐射的5个主要因子: 瑞利散射、臭氧和水汽吸收、气溶胶散射以及地表和大气间的多次反射。从3个方面考虑了复杂地形对于光合有效辐射的影响: (1) 坡度和坡向; (2) 天空可视角; (3) 邻近地形的附加辐射。提取2006年晴空条件下的估算结果与中国生态网络山东禹城站和长白山站的实测值的比较, 得到相关系数分别为0.924和0.9, 表明模型反演结果能够较好地解译实际光合有效辐射的变化。通过比较考虑地形和不考虑地形2种情况得到的光合有效辐射, 定量地分析了地形对光合有效辐射的影响。 相似文献
16.
A. K. Mishra 《Journal of the Indian Society of Remote Sensing》2014,42(4):877-883
The vegetation index is derived using many remote sensing sensors. Vegetation Index is extensively used and remote sensing has become the primary data source. Number of vegetation indices (VIs) have been developed during the past decades in order to assess the state of vegetation qualitatively and quantitatively. Analysis of vegetation indices has been carried out by many investigators scaling from regional level to global level using the remote sensing data of varying spatial, temporal and radiometric resolutions. There are as many as 14 VIs in use. Globally operational algorithms for generation of NDVI have utilized digital counts, at sensor radiances, ‘normalized’ reflectance (top of the atmosphere), and more recently, partially atmospheric corrected (ozone absorption and molecular scattering) reflectance. Presently NDVI and EVI are standard MODIS data products which are widely used by the scientific community for environmental studies. The OCM sensor in Oceansat 2 is designed for ocean colour studies. The OCM sensor has been used for studying ocean phytoplankton, suspended sediments and aerosol optical depth by many investigators. In addition to its capability of studying the ocean surface, OCM sensor has also the potential to study the land surface features. In a past EVI has been retrieved using OCM sensor of Oceansat 1. However, there is slight change in the band width of Oceansat 2—OCM sensor compared with OCM of Oceansat 1 sensor. In the present paper an attempt has been made to derive EVI using Oceansat 2 OCM sensor and the results have been compared with MODIS data. The enhanced vegetation index (EVI) is calculated using the reflectance values obtained after removing molecular scattering and ozone absorption component from the total radiance detected by the sensor. The band-2, Band-3, band-6 and band-8 corresponding to Blue, Red and Infrared part of the visible spectrum have been used to determine EVI. The result shows that Oceansat 2 derived EVI and MODIS derived EVI are well correlated. 相似文献
17.
短波红外通道卫星CO2遥感是近年国际研究热点。首先,开展了卫星观测对气溶胶及大气温度的敏感性研究;其次,针对基于最优化理论的非线性迭代反演方法反演过程中的不收敛问题,提出了修正的阻尼牛顿方法(MDNM),并利用模拟数据评估了MDNM方法的有效性;最后,利用GOSAT卫星数据反演CO2的垂直混合比浓度,并与地基TCCON站点数进行比对。研究结果表明:短波近红外CO2卫星遥感受气溶胶散射及温度影响明显;通过地基比对初步验证了MDNM具有良好的精度,两者的相关性R2达到了0.729。 相似文献
18.
查找表方法确定气溶胶类型 总被引：2，自引：0，他引：2
针对传统气溶胶类型确定方法的局限性以及当前气溶胶类型确定存在的困难,提出一种使用多波段气溶胶光学厚度数据确定气溶胶类型的方法。基于大气颗粒物的散射与吸收特性分析,通过构建查找表的方法实现气溶胶类型的确定。该方法利用Mie散射理论通过正向模拟不同类型气溶胶粒子数量与多波段光学厚度之间的关系来构建查找表,基于该查找表,使用440 nm、670 nm、870 nm及1020 nm 4个波段的气溶胶光学厚度确定气溶胶类型。使用模拟的多波段气溶胶光学厚度数据开展了气溶胶类型的确定实验,分析了不同波段气溶胶光学厚度误差对气溶胶类型确定结果的影响。结果表明,该方法可根据4个波段的气溶胶光学厚度以较高的精度确定出沙尘性、水溶性和煤烟3种气溶胶粒子的数量,从而确定气溶胶类型。 相似文献