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Water target based cross-calibration of CBERS-02.CCD camera with MODIS data

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Science china(Technological Sciences) 2005年第S2期48卷 61-71页

作者： TANG Junwu1,2. GU Xingfa2. NIU Shengli1, MA Chaofei1 & MIN Xiangjun3 1. National satellite Ocean Application Service (NSOAS), beijing 100081,{2. 2. State Key Laboratory of Remote Sensing Science, beijing 100010,{2. 3.{2. center for resource satellite data and applications (CRESDA), beijing 100083,{2. National satellite Ocean Application Service (NSOAS) Beijing 100081 China

In order to make quantitative watercolor sensing with china-Brazil Earth resources {2. (CBERS-02. CCD camera, the MODIS data with higher accuracy is used to cross-calibrate the CCD camera over water targets. In homogeneous clear water area, two pairs of images obtained over the same area on the same day by the two sensors are selected. The top-of-atmosphere (TOA) radiances of the multispectral bands of CCD are calculated with the water and aerosol parameters from MODIS based on a water-atmosphere radiative transfer algorithm. The stripes in CCD image that caused by unequal response of the CCD array detectors are firstly removed before making the cross-calibration. The same part of CCD detectors is selected for the calibrations in the two images to eliminate the residual error of destriping and uniformity correction for the focus plane irradiance. It is shown that the calibration results from two different images are consistent. The error of this method is about 5%.

关键词： CBERS-02 CCD MODIS radiometric calibration cross-calibration. DOI: 10.1360/05ze1006

Study on the relative radiometric correction of CBERS satellite CCD image

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Science china(Technological Sciences) 2005年第S2期48卷 12-28页

作者： GUO Jianning, YU Jin, ZENG Yong, XU Jianyan, PAN Zhiqiang & HOU Minghui china center for {2. satellite data and Application, beijing 100830, china china center for {2. satellite data and Application

The main payload on CBERS-01/02.of china-Brazil Earth resources {2. (CBERS) is a push-broom CCD camera with moderate spatial and radiant resolution. Because at lab the data for calibration at {2. assembly stage were unable to be collected, and also because the onboard calibrator after launch was in a different state from imaging, the calibration of CCD image got a series of difficulties involved. In practice, two methods are used in the processing on the ground station: One is extracting calibration data by statistics from the image itself, and the other is the method of histogram match. It was proved that the latter can calibrate the image much better, because it can remove the effect of unstable response of the camera largely and also can overcome the nonlinearity of the camera basically by using Look-Up Table (LUT) calculated from histogram statistics of different temporal images. Considering the problems of CBERS-01, a lot of calibration tests were done before the launch of CBERS-02. in which a set of lab coefficients for relative calibration was formulated after the data collection by using integration-hemisphere in the stage of {2. assembly test. During the on-orbit test, it was found that the calibration result from such coefficients was not satisfying, especially there being response difference between 3 detector arrays, which was attributed to the unstable dark currents of the CCD camera. This paper comes up with a statistic method to remove such response difference. In this method the middle detector array was used as reference to find the response differences of adjacent similar features between these arrays and it was proved to have a broad adaptability.

关键词： CBERS satellite CCD camera relative radiometric calibration relative radiometric correction assembly test.

The quantification of remote sensing

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Science china(Technological Sciences) 2005年第S2期48卷 1-11页

作者： GU Xingfa1,2.3,TIAN Guoliang1,2. LI Xiaowen1,2.& GUO Jianning4 1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing applications of Chinese Academy of Sciences and beijing Normal University, beijing 100101, china 2. The center for National Spaceborne Demonstration, beijing 100101, china 3. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 4. china center for resource satellite data and Application, beijing 100830, china State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China

The paper firstly defined the remote sensing information quantification, analyzed the necessity of developing remote sensing quantification, figured out the application guidelines requirement, and pointed out the importance of quantification research. Then taking the remote sensing application research of CBERS-02.data quantification as the example, the paper described the whole quantification system of “remotely sensed digital signal-radiation information-field parameter inversion”. Finally the paper gave the prospect for the development trend of the quantitative remote sensing.

关键词： remote sensing information quantification CBERS-02 radiometric calibration surface parame- ter reversion.

Improving the accuracy of image-based forest fire recognition and spatial positioning

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Science china(Technological Sciences) 2010年第S1期53卷 184-190页

作者： JIANG LiLi 1,QI QingWen 1,ZHANG An 1,GUO ChaoHui 2.& CHENG Xi 1,3 1 Institute of Geographical Sciences and Natural resources Research,Chinese Academy of Sciences,beijing 100101,{2. 2.3} center for resources satellite data and applications,beijing 100094,{2. 3Graduate University of Chinese Academy of Sciences,beijing 100049,{2. Institute of Geographical Sciences and Natural resources Research Chinese Academy of Sciences Beijing China china center for {2.s satellite data and applications Beijing China Graduate University of Chinese Academy of Sciences Beijing China

Forest fires are frequent natural *** is necessary to explore advanced means to monitor,recognize and locate forest fires so as to establish a scientific system for the early detection,real-time positioning and quick fighting of forest *** paper mainly expounds methods and algorithms for improving accuracy and removing uncertainty in image-based forest fire recognition and spatial ***,we discuss a method of forest fire recognition in visible-light *** are four aspects to improve accuracy and remove uncertainty in fire recognition:(1)eliminating factors of interference such as road and sky with high brightness,red leaves,other colored objects and objects that are lit up at night,(2.excluding imaging for specific periods and azimuth angles for which interference phenomena repeatedly occur,(3)improving the thresholding method for determining the flame border in image processing by adjusting the threshold to the season,weather and region,and (4)integrating the visible-light image method with infrared image ***,we examine infrared-image-based methods and approaches of improving the accuracy of forest fire recognition by combining the spectrum threshold with an object feature value such as the normalized difference vegetation index and excluding factors of disturbance such as interference signals,extreme weather and high-temperature ***,a method of visible analysis to enhance the accuracy of forest fire positioning is examined and realized;the method includes decreasing the visual angle,selecting central points,selecting the largest spots,and judging the selection of fire spots according to the central *** studies are examined and the results are found to be satisfactory.

关键词： forest fire monitoring spatial positioning accuracy improvement

Radiometric cross-calibration of the CBERS-02.CCD camera with the TERRA MODIS

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Science china(Technological Sciences) 2005年第S2期48卷 44-60页

作者： LI Xiaoying1,2.3, GU Xingfa1,3,4, MIN Xiangjun5, YU Tao1,3, FU Qiaoyan5, ZHANG Yong1,2.3 & LI Xiaowen1,3 1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing applications of Chinese Academy of Sciences and beijing Normal University, beijing 100101, china 2. Graduate University of Chinese Academy of Sciences, beijing 100039, china 3. The center for National Spaceborne Demonstration, beijing 100101, china 4. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 5. china center for resource {12. data and Application, beijing 100830, china State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China

For the application of the CCD camera, the most important payload on CBERS-02. the key is to provide long-term stable radiometric calibration coefficients. Although the vicarious calibration had been proved successful, it had its limitations such as test site requirement and unsuitable for historical data. Cross-calibration is one of the alternative methods, but it needs synchro surface spectrum to achieve spectral band matching factors. Our effort is to probe the influences on these factors. Simulations with a lot of surface spectrum showed that the factors changed with the viewing geometry, atmospheric condition and surface targets. However, simulating with the same viewing geometry and atmospheric condition, the spectral band matching factors of the same or similar surface targets’ spectrum acquired from different dates and different places would like to be consistent to each other within 1%―5%. Thus, the synchro measurement data can be substituted by the same or similar target from other source. Based on this method, using the MODIS as the reference, the cross-calibration was performed for CCD camera. The research demonstrated that the traditional method with single calibration site was inappropriate for CCD camera, since the offsets for its four spectral bands were not zeros. With four calibration sites, these offsets were obtained. And the camera was detected to degrade with dates based on four times of cross-calibrations.

关键词： CBERS-02 CCD camera cross-calibration the spectral band matching factors.

In flight MTF monitoring and compensation for CCD camera on CBERS-02

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Science china(Technological Sciences) 2005年第S2期48卷 29-43页

作者： GU Xingfa1,2.3, LI Xiaoying1,2.4, MIN Xiangjun5, YU Tao1,2. SUN Jijuan5, ZENG Yong1,2.4, XU Hua1,2.& GUO Ding2.6 1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing applications of Chinese Academy of Sciences and beijing Normal University, beijing 100101, china 2. The center for National Spaceborne Demonstration, beijing 100101, china 3. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 4. Graduate University of Chinese Academy of Sciences, beijing 100039, china 5. china center for resource {12. data and Application, beijing 100830, china 6. University of Electronic Science and Technology of china, Chengdu 610054, china State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University The center for National Spaceborne Demonstration

In this article, the approach of simulating ideal tarp scene was proposed to determine the MTF for CCD camera on CBERS-02. The MTF acquired from this technique was compared to those from some common methods. MTFs achieved from different approaches were employed to compensate the CCD images based on three restoration algorithms: the iterative method, the Wiener filter and the modified inverse filter (MIF). The two-dimensional MTF was established with the value at frequency 0.5 for 45° directional MTF as the value at its four corners. This article addressed the variations of the restored CCD images with different techniques of constructing two-dimensional MTF, restoring algorithms and determining the in-flight MTFs. Results showed images restored with the MTF determined from the technique of simulating ideal tarp scene represent the real scene best. And the restoration technique based on the MIF would produce better restored images than the other two techniques. This research also demonstrated that the two-dimensional MTF used for restoration should be interpolated under the control of the MTF for 45° axis, rather than by multiplying the cross-orbit MTF with along-orbit MTF.

关键词： CBERS-02 CCD MTF the technique of simulating ideal tarp scene.

Contribution of cloud condensate to surface rainfall process

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Progress in Natural Science:Materials International 2006年第9期16卷 967-973页

作者： ZHOU Yushu , GUI Xiaopeng and LI Xiaofan ( Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 10002., china Joint {2. for satellite data Assimilation and NOAA/NESDIS/Office of Research and applications Camp Springs, Maryland, USA) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Joint center for satellite {2. Assimilation and NOAA/NESDIS/Office of Research and applications Camp Springs Maryland USA

Contribution of cloud condensate to surface rainfall processes is investigated in a life span of tropical convection based on hourly data from a two-dimensional cloud resolving simulation. The model is forced by the large-scale vertical velocity, zonal wind and horizontal advections obtained from tropical ocean global atmosphere coupled ocean-atmosphere response experiment (TOGA COARE). The results show that during the genesis, development, and decay of tropical convection, calculations with water vapor overestimate surface rain rate, and cloud condensate plays an important role in correcting overestimation in surface rain rates. The analysis is carried out in deep convective clouds and anvil clouds during the development of tropical convection. The surface rain rates calculated with water vapor in deep convective clouds and anvil clouds have similar magnitudes, the large surface rain rate appears in deep convective clouds due to the consumption of water hydrometeors whereas the small surface rain rate occurs in anvil clouds because of the gain of ice hydrometeors. Further analysis of the grid data shows that the surface rain rates calculated with water vapor and with cloud condensate are negatively correlated with the correlation coefficient of - 0.85, and the surface rain rate calculated with cloud condensate is mainly contributed to the water hydrometeors in the tropical deep convective regime.

关键词： cloud condensate surface rain rate cloud resolving simulation.

Diagnostic analysis of mesoscale rainstorms in the Jiang-Huai valley of china with convective vorticity vector

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Progress in Natural Science:Materials International 2007年第5期17卷 559-568页

作者： Cui Xiaopeng, Gao Shouting and Li Xiaofan (Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS), Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 10002., china Joint {2. for satellite data Assimilation and NOAA/NESDIS/{2. for satellite applications and Research, Camp Springs, Maryland, USA) Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Joint center for satellite {2. Assimilation and NOAA/NESDIS/center for satellite applications and Research Camp Springs Maryland USA

By the vector product of absolute vorticity vectors and equivalent potential temperature gradients, a new vector, convec-tive vorticity vector (CVV) is readdressed after Gao et al., and is applied to the study of the development and movement of mesoscale rainstorms in the Jiang-Huai valley of china by using high-resolution simulation data with PSU/NCAR MM5 briefly. The results show that the CVV, especially its vertical component which is closely related to interactions between vertical secondary circulations and horizontal equivalent potential temperature gradients, may be a good tracer and diagnostic tool in the study of mesoscale rainstorms in the Jiang-Huai valley of china. And the main physical processes responsible for the variations of the vertical component of the CVV are discussed briefly based on its tendency equation proposed in this article.

关键词： convective vorticity vector mesoscale rainstorms tendency equations.

Cloud microphysical and rainfall responses to zonal perturbations of sea surface temperature:A cloud-resolving modeling study

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Progress in Natural Science:Materials International 2009年第5期19卷 587-594页

作者： Xiaopeng Cuia, Xiaofan Lib, Zhiping Zongc a Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS), Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 10002., china b Joint {2. for satellite data Assimilation and NOAA/NESDIS/Office of Research and applications, Camp Springs, MD, USA c National Meteorological {2., china Meteorological Administration, beijing 100081, china Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Joint center for satellite {2. Assimilation and NOAA/NESDIS/Office of Research and applications Camp Springs MD USA National Meteorological center China Meteorological Administration Beijing 100081 China

The cloud microphysical and rainfall responses to zonal perturbations of sea surface temperature (SST) are investigated by analyzing the equilibrium simulation data (from day 31-40) obtained from a series of two-dimensional cloud-resolving simulations with a zonal model domain of 768 km. Four experiments imposed by zonal SST perturbations of wavenumbers 1 (SST2.Z1), 2.(SST2.Z2., 4 (SST2.Z4), and 8 (SST2.Z8) are compared to the control experiment imposed by zonally uniform SST (SST2.). The model domain mean SST is 2. °C, and the two-dimensional cloud-resolving model with a cyclic lateral boundary is also imposed by zero vertical velocity and constant zonal wind. The time and model domain mean surface rain rates in SST2.Z1, SST2.Z2. and SST2.Z8 are about 10% larger than those in SST2., whereas the mean surface rain rates in SST2.Z4 and SST2. are similar. The analysis of mean surface rainfall budgets shows that local water vapor and hydrometeor changes play important roles in determining the differences and similarities in mean surface rain rate between the perturbation experiments and the control experiment. Both convective and stratiform rain rates are larger in SST2.Z1 and SST2.Z2.than in SST2. due to the smaller advection of rain from convective regions into raining stratiform regions and the larger vapor condensation rates associated with the larger water vapor convergence over raining stratiform regions in SST2.Z1 and SST2.Z2. The convective rain rates are larger in SST2.Z4 and SST2.Z8 than in SST2. because of the larger condensation rates associated with the larger water vapor convergence over convective regions in SST2.Z4 and SST2.Z8. The stratiform rain rates in SST2.Z4 and SST2.Z8 are smaller than in SST2. due to the smaller vapor condensation rates and smaller collection rates of cloud water by rain over raining stratiform regions in SST2.Z4 and SST2.Z8.

关键词： Cloud microphysical and rainfall responses Sea surface temperature Zonal perturbation Cloud-resolving modeling study