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1.
通用劈窗算法的NOAA-18(N)AVHRR/3数据地表温度遥感反演与验证 总被引：1，自引：0，他引：1
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
2.
Landsat-8卫星设计有2个热红外波段,但由于第11波段存在定标问题,无法用于定量研究,所以基于Landsat-8的地表温度反演算法目前仍以单通道为主。单通道算法反演地表温度需先已知地表比辐射率并完成大气校正的工作。在大气校正方面,现有的算法主要以传统方法为主,即通过大气辐射传输模型或经验-半经验公式的方式获取大气参数。但是,传统的经验-半经验的方法并不建立在物理机制上,其自身存在一定局限性;而大气辐射传输模型的方法虽然精度更高,但执行效率较低,不适用于业务化的产品生产。本文针对现有大气估算方法的不足,提出了一种基于Landsat-8单通道地表温度反演的大气参数快速估算方法。在水汽范围0~6 g/cm2内,大气参数快速估算方法的精度与MODTRAN精度相当,大气透过率RMSE为0.003;大气上行辐亮度RMSE为0.0004;大气下行辐亮度RMSE为0.0004。相较于传统的大气参数估算方法,本文提出的大气参数快速估算方法,不仅可以脱离大气辐射传输模型使用,而且具有与其相当的估算精度,执行效率更高,适用性更广。 相似文献
3.
简要介绍GPS-LEO掩星大气反演算法的基本原理，考虑到多种误差源对反演大气参数带来的影响，利用EGOPS仿真模拟软件，采用三维射线追踪法模拟了1 d 内426个掩星事件，并统计分析多种误差源的影响特性。通过反演温度的统计分析发现，现有的卫星钟稳定性以及卫星定轨精度可以满足反演需求；噪声误差对反演影响较大，需要采取有效措施抑制；多路径效应中，周期误差影响较小，但振幅对反演结果有一定影响，需要有效抑制。 相似文献
4.
地表温度是反映地表环境的一个重要参数,精确获取地表温度的方法对研究城市热岛效应、进行生态环境监测评价是必不可少的。利用遥感手段进行地表温度的反演是一种较新颖的方法,相对成熟的反演算法主要有单通道算法、辐射传输方程法及单窗算法。本文以山东省威海市Landsat TM数据为例,分别利用辐射传输方程法和单窗算法进行地表温度反演,通过遥感目视解译的方法提取研究区各类典型地物对应的地表温度,进行统计分析,结果表明,两者反演得到的地表温度具有一致的变化趋势,其中单窗算法中不同典型地物的地表温度整体标准差较小,如建设用地为0.530,起伏波动小,算法精度略优于辐射传输方程法。 相似文献
5.
热红外地表方向性辐射温度与半球辐射温度关系研究 总被引：1，自引：0，他引：1
地表温度是陆面过程的一个重要影响因素,利用地表温度的遥感反演算法只能获取卫星传感器观测角度条件下的地表温度（即某个方向上的辐射温度）,但地球表面普遍存在非同温像元,反演得到的像元地表辐射温度具有方向性特征。本文利用热红外辐射传输模型4 SAIL（Scattering by Arbitrarily Inclined Leaves）,以及方向性热辐射参数化模型,针对非同温均匀冠层,考虑冠层结构、太阳位置和观测角等因素的影响,模拟得到方向性辐射温度数据,与半球辐射温度数据比较,得到估算半球辐射温度的最佳观测角度。此外,开展热红外地面观测试验,对热红外地表辐射温度的角度效应,以及利用模拟数据得到的半球辐射温度最佳观测角度进行了验证。结果表明,当太阳高度角较低时,均匀草地的地表辐射温度,会随着观测天顶角的增大而增加,受观测方位角的影响较小,当观测天顶角为75°时,倾斜观测与垂直观测得到的辐射温度差值达到2.7 K,说明热辐射存在明显的方向性特征。同时,将热红外地表方向性辐射温度与同步观测的半球辐射温度进行对比分析,当叶面积指数小于1.0时,半球辐射温度的最佳替代角度为51°,与模拟结果相符。 相似文献
6.
TM热波段图像的地表温度反演算法与实验分析 总被引：27，自引：1，他引：26
目前利用LandsatTM热波段数据反演地表温度有3种算法:辐射传导方程法、单窗算法和单通道算法。辐射传导方程法由于计算过程复杂且需要实时大气剖面数据,因而实际应用较为困难。单窗算法和单通道算法对Landsat热波段反演地表温度能获得较高精度。单窗算法所需的大气参数包括近地表气温和大气水分含量,单通道算法所需的大气参数仅为大气水分含量。地表辐射率为这两种算法共有的关键参数。本文以福建省福州市为研究区,使用1989年6月15日LandsatTM数据,利用单窗算法和单通道算法对研究区进行地表温度反演,并将这两种算法的反演结果与研究区反演的亮度温度进行了比较,结果表明:(1)两种算法反演的结果总体趋势比较接近,但单窗算法的结果相对于单通道算法较低,二者相差约2.45℃;(2)两种算法的结果与亮度温度相比,单窗算法要高出约2.84℃,而单通道算法则要高出约5.28℃。 相似文献
7.
大气下行辐射简化计算及朗伯假设下大气下行辐射效应计算分析 总被引：1，自引：1，他引：0
地表温度反演及真实性检验必须考虑大气下行辐射效应,其简化计算通常假设地表为朗伯体以及大气下行辐射各向同性。本文从理论和方法上分析了大气下行辐射简化计算公式,提出了以某个最佳角度下行辐射值作为半球方向下行辐亮度的平均值来估算大气下行辐射的方法,研究了地表朗伯假设对大气下行辐射效应及传感器入瞳处总辐射的影响,给出了朗伯假设导致的最大可能相对误差的表达式。研究以TERRA-MODIS热红外通道31和32为例,以内蒙古二连浩特地区草场为研究区,输入2004年的探空资料和地温数据到大气辐射传输模型进行实验论证和数值模拟,得到以下初步结论:①对于二连浩特这样的典型内陆地区,忽略大气下行辐射效应最多能引起4K的误差,且随着卫星扫描角增加大气下行辐射效应在增加;②半球空间大气下行辐亮度为各向同性假设不是很合适,但可以获取某个最佳角度的下行辐射作为半球方向下行辐射平均值,以简化计算大气下行辐照度,对于二连浩特地区最佳角度取57°;③地表朗伯假设对大气下行辐射效应计算有影响,最大可能相对误差可达33.3%,随着卫星扫描角增加误差随之减少,综合考虑大气下行辐射效应占总辐射的比重,地表朗伯假设对总辐射影响不大,其带来的误差在可接受范围内。 相似文献
8.
使用FY-3C气象卫星GNSS掩星数据反演得到2017-03-01～2018-02-28大气温度廓线,并估计对流层顶高度变化;然后利用探空气球数据和ERA5模型数据进行验证;最后以2°×2°的空间分辨率将中国区域划分为608个网格,针对每一个单元格,分别计算对流层顶参数,建立格网模型,分析中国区域对流层顶参数的时空分布... 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.
ASTER遥感成像仪发射以来,提供了廉价的多光谱热红外遥感数据,为热红外遥感技术在诸多领域的应用注入了新的活力。本文在分析热红外技术在岩矿领域应用潜力的基础上,将热红外遥感技术应用于花岗岩铀矿找矿中,并以华南某花岗岩铀矿田为例,基于ASTER热红外数据进行了影像镶嵌、辐射定标、大气校正、温度/发射率分离,及其不同波段比值组合模拟的反演算法,对发射率数据进行SiO2含量的定量反演,在反演图上识别出了研究区内明显的硅化断裂带、酸性岩及红层分布信息,识别结果与地质事实相符,并在野外得到了验证。实践表明,热红外遥感技术在花岗岩铀成矿要素提取中效果良好,并将在铀矿找矿工作中发挥积极的指导作用。 相似文献
11.
光学遥感大气订正模型及其相关问题分析 总被引：4，自引：2，他引：2
首先说明了大气的影响作用和大气订正的必要性。接着总结了大气订正的基本问题:侧重分析了大气订正的模型和反演方法;还包括大气、气溶胶参数的反演;辐射传输软件用于大气订正函数的计算;邻近效应的处理;查找表的创建;大气订正的精度分析等。 相似文献
12.
Yunfei Bao Shengbo Chen 《东北亚地学研究》2006,9(1):100-108
IntroductionThe radiance leaving the earth-atmosphere sys-tem which can be sensed by a satellite borne ra-diometer is the sum of radiation emission fromtheearth surface and each atmospheric level that aretransmittedtothe top of the atmosphere.The radia-tion emissionfromthe earthsurface andthe radianceof each atmospheric level can be separated fromtheradiance at the top the atmospheric level a satellitemeasured.Thus,the earth surface parameters willbe retrieved from the surface radiance after a… 相似文献
13.
The radiance leaving the earth-atmosphere system which can be sensed by a satellite borne radiometer is the sum of radiation emission from the earth surface and each atmospheric level that are transmitted to the top of the atmosphere. The radiation emission from the earth surface and the radiance of each atmospheric level can be separated from the radiance at the top the atmospheric level measured by a satellite borne radiometer. However, it is very difficult to measure the atmospheric radiance, especially the synchronous measurement with the satellite. Thus some atmospheric radiative transfer models have been developed to provide many options for modeling atmospheric radiation transport, such as LOWTRAN, MODTRAN, 6S, FASCODE, LBLRTM, SHARC, and SAMM. Meanwhile, these models can support the detailed detector system design, the optimization and evaluation of satellite mission parameters, and the data processing procedures. As an example, the newly atmospheric radiative transfer models, MODTRAN will be compared with other models after the atmospheric radiative transfer is described. And the atmospheric radiative transfer simulation procedures and their applications to atmospheric transmittance, retrieval of atmospheric elements, and surface parameters, will also be presented. 相似文献
14.
Chaos particle swarm optimization combined with circular median filtering for geophysical parameters retrieval from Windsat 总被引：1，自引：0，他引：1
This paper established a geophysical retrieval algorithm for sea surface wind vector, sea surface temperature, columnar atmospheric water vapor, and columnar cloud liquid water from WindSat, using the measured brightness temperatures and a matchup database. To retrieve the wind vector, a chaotic particle swarm approach was used to determine a set of possible wind vector solutions which minimize the difference between the forward model and the WindSat observations. An adjusted circular median filtering function was adopted to remove wind direction ambiguity. The validation of the wind speed, wind direction, sea surface temperature, columnar atmospheric water vapor, and columnar liquid cloud water indicates that this algorithm is feasible and reasonable and can be used to retrieve these atmospheric and oceanic parameters. Compared with moored buoy data, the RMS errors for wind speed and sea surface temperature were 0.92 m s~(-1) and 0.88℃, respectively. The RMS errors for columnar atmospheric water vapor and columnar liquid cloud water were 0.62 mm and 0.01 mm, respectively, compared with F17 SSMIS results. In addition, monthly average results indicated that these parameters are in good agreement with AMSR-E results. Wind direction retrieval was studied under various wind speed conditions and validated by comparing to the Quik SCAT measurements, and the RMS error was 13.3?. This paper offers a new approach to the study of ocean wind vector retrieval using a polarimetric microwave radiometer. 相似文献
15.
Improvement of mono-window algorithm for retrieving land surface temperature from HJ-1B satellite data 总被引：2，自引：0，他引：2
The thermal infrared channel (IRS4) of HJ-1B satellite obtains view zenith angles (VZA) up to ±33°. The view angle should be taken into account when retrieving land surface temperature (LST) from IRS4 data. This study aims at improving the mono-window algorithm for retrieving LST from IRS4 data. Based on atmospheric radiative transfer simulations,a model for correcting the VZA effects on atmospheric transmittance is proposed. In addition,a generalized model for calculating the effective mean atmospheric temperature is developed. Validation with the simulated dataset based on standard atmospheric profiles reveals that the improved mono-window algorithm for IRS4 obtains high accuracy for LST retrieval,with the mean absolute error (MAE) and root mean square error (RMSE) being 1.0 K and 1.1 K,respectively. Numerical experiment with the radiosonde profile acquired in Beijing in winter demonstrates that the improved mono-window algorithm exhibits excellent ability for LST retrieval,with MAE and RMSE being 0.6 K and 0.6 K,respectively. Further application in Qinghai Lake and comparison with the Moderate-Resolution Imaging Spectroradiometer (MODIS) LST product suggest that the improved mono-window algorithm is applicable and feasible in actual conditions. 相似文献
16.
The radiative transfer is one of the significant theories that describe the processes of scattering, emission, and absorption of electromagnetic radiant intensity through scattering medium. It is the basis of the study on the quantitative remote sensing. In this paper, the radiative characteristics of soil, vegetation, and atmosphere were described respectively. The numerical solution of radiative transfer was accomplished by Successive Orders of Scattering （SOS）. A radiative transfer model for simulating microwave brightness temperature over land surfaces was constructed, designed, and implemented. Analyzing the database generated from soil-vegetation-atmosphere radiative transfer model under Advanced Microwave Scanning Radiometer-Earth Observing System （AMSR-E） configuration showed that the atmospheric effects on microwave brightness temperature should not be neglected, particularly for higher frequency, and can be parameterized. At the same time, the relationship between the emissivities of the different channels was developed. The study results will promote the development of algorithm to retrieve geophysical parameters from microwave remotely sensed data. 相似文献
17.
HY-2A is the first one of the Chinese HY-2 ocean satellite series carrying a microwave radiometer(RM) to measure sea surface temperature,sea surface wind speed,atmospheric water vapor,cloud liquid water content, and rain rate. We verified the RM level 1B brightness temperature(T_B) to retrieve environmental parameters. In the verification, TB that simulated using the ocean-atmosphere radiative transfer model(RTM) was used as a reference. The total bias and total standard deviation(SD) of the RM level 1B T_B, with reference to the RTM simulation, ranged-20.6-4.38 K and 0.7-2.93 K, respectively. We found that both the total bias and the total SD depend on the frequency and polarization, although the values for ascending and descending passes are different. In addition, substantial seasonal variation of the bias was found at all channels. The verification results indicate the RM has some problems regarding calibration, e.g.,correction of antenna spillover and antenna physical emission, especially for the 18.7-GHz channel. Based on error analyses, a statistical recalibration algorithm was designed and recalibration was performed for the RM level 1B T_B. Validation of the recalibrated TB indicated that the quality of the recalibrated RM level 1B T_B was improved significantly. The bias of the recalibrated TB at all channels was reduced to 0.4 K, seasonal variation was almost eradicated, and SD was diminished(i.e., the SD of the 18.7-GHz channel was reduced by more than 0.5 K). 相似文献
18.
MODIS数据的云顶高度反演 总被引：2，自引：0，他引：2
云的辐射特性和它的高度影响到辐射的收支可以导致地球的变暖或变冷,在地球大气能量收支平衡中．云具有特别显著的调节作用,是影响气候变化的一个重要因子。云顶性质包括云顶气压、云顶温度和有效云量或有效比辐射率。很多方法被用来从多光谱资料中估计云参数,而CO2薄片算法(截断法)则是使用被动遥感资料反演云顶性质的重要方法之一。利用15μmCO2吸收带的几个吸收不同的MODIS红外波段,对于大气不同高度层次的不同敏感度,通过从地球大气系统的几个CO2波段同时测量向上红外辐射,以及大气的温度和透射率廓线的基础上,可以推断出云顶气压。这项技术应用于HIRS资料上已经有20年的历史,而EOS系列地球环境卫星的升空,使EOS上搭载的MODIS探测器成为第一个拥有CO2薄片波段的高空间分辨率探测器。本文依据CO2薄片算法(截断法)的理论模型结合实例讨论算法的特点及不足,同时分析其误差以利改进。 相似文献