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Principle and application of three-band gradient difference vegetation index

Science China Earth Sciences 2005年第2期48卷 241-249页

作者： TANG Shihao, ZHU Qijiang, WANG Jindi, ZHOU Yuyu & ZHAO Feng Research center for Remote Sensing and GIS, Department of Geography, beijing Normal University, beijing 100875. China national satellite {5. center, China {5. Administration, beijing 100081, China 1. Research center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China 2. national satellite meteorological center China Meteorological Administration 100081 Beijing China

Vegetation index is a simple, effective and experiential measurement of terrestrial vegetation activity, and plays a very important role in qualitative and quantitative remote sensing. Aiming at shortages of current vegetation indices, and starting from the analysis of vegetation spectral characteristics, we put forward a new vegetation index, the three-band gradient difference vegetation index (TGDVI), and established algorithms to inverse crown cover fraction and leaf area index (LAI) from it. Theoretical analysis and model simulation show that TGDVI has high saturation point and the ability to remove the influence of background to some degree, and the explicit functional relation with crown cover fraction and LAI can be established. Moreover, study shows that TGDVI also has the ability to partly remove the influence of thin cloud. Experiment in the Shunyi District, beijing, China shows that reasonable result can be reached using the vegetation index to retrieve LAI. We also theoretically analyzed the reason why the normalized difference vegetation index (NDVI) owns the low saturation point, and show that it is determined by the definition of NDVI and the characteristic of vegetation spectra, and is unavoidable to some degree. Meanwhile, through model simulation, we also indicate that the relationship between simple ratio vegetation index (SR) and LAI closes to a piecewise linear one instead of a linear one, which is mainly caused by the influence of background and different change rates of reflectance in red and infrared bands with LAI increasing.

关键词： vegetation index, remote sensing, LAI, crown cover fraction, remote sensing inversion.

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Ocean color products retrieval and validation around China coast with MODIS

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Acta Oceanologica Sinica 2010年第4期29卷 21-27页

作者： SUN Lingt GUO Maohua WANG Xiaomei Key Laboratory of Radiometric Calibration and Validation for Environmental satellites China Meteorological Administration （LRCVES/CMA） National Satellite Meteorological Center China Meteorological Administration Beijing 100081 China national satellite Ocean Application Service State Oceanic Administration Beijing 100081 China

Waters along China coast are very turbid with high concentrations of suspended sediment nearly all the time,especially at the Hangzhou Bay,the Changjiang （Yangtze） River Estuary and the shoal along Jiangsu *** these turbid and optically complex waters,the standard MODIS ocean color products tend to have invalid *** the water-leaving radiances in the near-infrared （NIR） are significant resulting from the strong scattering of suspended particles,the standard MODIS atmospheric correction algorithm often gets no results or produces significant *** because of the complex water optical properties,the OC3 model used in the standard MODIS data processing tends to get extremely high chlorophyll-a （Chl-a） *** this paper,we present an atmospheric correction approach using MODIS short wave infrared （SWIR） bands based on the fact that water-leaving radiances are negligible in the SWIR region because of the extreme strong absorption of water even in turbid waters.A regional Chl-a concentration estimation model is also constructed for MODIS from in situ *** algorithms are applied to MODIS Aqua data processing in the China coastal *** situ data collected in the Yellow Sea and the East China Sea in spring and autumn,2003 are used to validate the *** good results have been *** is noted that water-leaving reflectance in the NIR bands are significant in waters along the China coast with high sediment *** satellite derived and in-situ reflectance spectra can match in the turbid waters along China coast,and there is relatively good linear relationship between satellite derived and in-situ *** RMSE value of Rrs（λ） is 0.0031 sr ？1 for all the nine ocean color bands （412 to 869 nm）.The satellite-derived Chl-a value is in the reasonable range and the root mean square percentage difference is 46.1%.

关键词： ocean color atmospheric correction chlorophyll-a MODIS China coastal region validation

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Absolute radiometric calibration of CBERS-02 IRMSS thermal band

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Science China(Technological Sciences) 2005年第S2期48卷 72-90页

作者： ZHANG Yong1,2,3, GU Xingfa1,3,4, YU Tao1,3, ZHANG Yuxiang5. CHEN Liangfu1,3, LI Xiaoying1,2,3, LI Xiaowen1,3 & HE Liming6 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. national satellite meteorological center, beijing 100081, China 6. State Environmental Protection Administration, beijing 100029, China Chinese Acad Sci Inst Remote Sensing Applicat State Key Lab Remote Sensing Sci Beijing 100101 Peoples R China beijing Normal Univ State Key Lab Remote Sensing Sci Beijing 100101 Peoples R China Chinese Acad Sci Grad Univ Beijing 100039 Peoples R China Ctr Natl Spaceborne Demonstrat Beijing 100101 Peoples R China INRA F-84914 Avignon France Natl satellite Meteorol Ctr Beijing 100081 Peoples R China State Environm Protect Adm Beijing 100029 Peoples R China

Based on the laboratory calibration before launch of CBERS-02 IRMSS thermal infrared channel, the onboard blackbody calibration, the radiometric cross- calibration against TERRA MODIS corresponding channel and the in-flight field calibration at Lake Qinghai: water surface radiometric calibration test site of China on Aug. 17, 2004 are carried out in this research. When making onboard blackbody calibration of CBERS-02 IRMSS, it is necessary to understand inside structures and light path in IRMSS camera and receive and process calibration blackbody signals at normal and high temperatures. Onboard blackbody calibration results of each detector are very important to relative radiometric calibration of images processing and absolute radiometric calibration of each detector. In-flight field calibration mainly contains field experiments, obtaining synchronous images, spectrum marching and MODTRAN radiative transmi- ssion computation. Radiometric cross-calibration of CBERS-02 IRMSS thermal band against TERRA MODIS selected 6 times synchronous images of two sensors passing through Lake Qinghai and Lake Taihu from August to December, 2004 to compute the cross calibration data. Combining the in-flight field calibration and radiometric cross calibration data, the absolute radiometric calibration coefficients are calculated by the linear regression method. This new calibration model can obviously control the radiometric calibration uncertainties aroused by the single point method used in the in-flight calibration of CBERS-02 IRMSS, this kind of sensors cannot receive the cosmic background radiation. In this research, the radiometric calibration coefficients obtained through the linear regression model are 8.5. (gain, unit: DN/W m?2sr?1μm?1) and 44.92 (offset, unit: DN).

关键词： CBERS-02 IRMSS thermal band in-flight field calibration onboard blackbody calibration cross calibration.

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Monitoring of the 2011 spring low ozone events in the Arctic region

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Chinese Science Bulletin 2011年第27期56卷 2893-2896页

作者： LIU NianQing 1,2 , HUANG FuXiang 1,2 WANG WeiHe 1,2 1 national satellite meteorological center, beijing 100081, China 2 Key Laboratory of Radiometric Calibration and Validation for Environmental satellites, China meteorological Administration, beijing 100081, China national satellite meteorological center Key Laboratory of Radiometric Calibration and Validation for Environmental satellites China Meteorological Administration

Data from FY-3B SBUS and NOAA SBUV/2 were used to monitor ozone levels in the Arctic region from March 1 to April 5. 2011. Results revealed a significant ozone depletion in the area, with total ozone levels between 200-25. DU. The ozone levels recorded were 100-200 DU below normal, and in some parts the levels were as low as 200 DU, indicating a mini ozone-hole. During the sampling period, the ozone depletion area underwent identifiable expansion and detraction, a rotation around the North Pole from the west to the east, and a longitudinal movement from the Pole, spreading to the mid latitudes. The effects of these rare low ozone events were not only felt in the Arctic, but also extended to densely populated areas between Europe and the middle of Russia. In this region, rapidly increasing levels of ultraviolet radiation were detected at the Earth's surface. Given the significant risk that this poses to both the environment and people's health, this occurrence has significant global implications.

关键词：北极地区臭氧水监测事件人口稠密地区中纬度地区 NOAA 调查结果

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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 100029, China b Joint center for satellite Data Assimilation and NOAA/NESDIS/Office of Research and Applications, Camp Springs, MD, USA c national meteorological center, China meteorological Administration, beijing 100081, China [a]Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China [b]Joint Center for Satellite Data Assimilation and NOAA/NESDIS/Office of Research and Applications Camp Springs MD USA [c]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 (SST29Z1), 2 (SST29Z2), 4 (SST29Z4), and 8 (SST29Z8) are compared to the control experiment imposed by zonally uniform SST (SST29). The model domain mean SST is 29 °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 SST29Z1, SST29Z2, and SST29Z8 are about 10% larger than those in SST29, whereas the mean surface rain rates in SST29Z4 and SST29 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 SST29Z1 and SST29Z2 than in SST29 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 SST29Z1 and SST29Z2. The convective rain rates are larger in SST29Z4 and SST29Z8 than in SST29 because of the larger condensation rates associated with the larger water vapor convergence over convective regions in SST29Z4 and SST29Z8. The stratiform rain rates in SST29Z4 and SST29Z8 are smaller than in SST29 due to the smaller vapor condensation rates and smaller collection rates of cloud water by rain over raining stratiform regions in SST29Z4 and SST29Z8.

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

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Sea-salt aerosol transport patterns over the Northern Hemisphere inferred from two subarctic ice core records

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Science China Earth Sciences 2005年第4期48卷 576-584页

作者： YAN Yuping1,2, KANG Shichang2,3,5. SUN Junying4,5. Paul A. Mayewski2 & QIN Dahe5.1. national Climate center, China meteorological Administration, beijing 100081, China 2. Climate Change Institute, University of Maine, Orono, ME 04469, USA 3. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, beijing 100085. China 4. Chinese Academy of meteorological Sciences, beijing 100081, China 5. Key Laboratory of Ice Core and Cold Regions Environment, Cold and Arid Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China 1. national Climate center China Meteorological Administration 100081 Beijing China 2. Climate Change Institute University of Maine 04469 Orono ME USA 3. Institute of Tibetan Plateau Research Chinese Academy of Sciences 100085 Beijing China 4. Key Laboratory of Ice Core and Cold Regions Environment Cold and Arid Environmental and Engineering Research Institute Chinese Academy of Sciences 730000 Lanzhou China 5. Chinese Academy of meteorological Sciences 100081 Beijing China

Atmospheric circulation reconstruction based on glaciochemical records requires knowledge of chemical concentration controls, such as source, transport pathway and strength. To gain insight into these processes, the relationships between glaciochemical records from two Northern Hemisphere sites (Mt. Logan in Yukon Territory and 20D in southern Greenland) and instrumental sea level pressure (SLP) series are investigated. Calibrations between Mt. Logan sea-salt sodium (ssNa+) concentration and SLP series show that ssNa+ concentrations are closely correlated with the autumntime (SON) Aleutian Low and the summertime (JJA) North Pacific Subtropical High. Both the deepened Aleutian Low and enhanced North Pacific Sub- tropical High strengthen the transport of sea-salt aerosols from the North Pacific to the Mt. Logan region. Calibrations between 20D ssNa+ concentrations and SLP series indicate that ssNa+ concentrations are closely related to the wintertime (Jan.) Icelandic Low. A deepening of the Icelandic Low strengthens winter storms and frequent cyclogenesis over the North Atlantic and pushes more sea-salt laden air masses to the Greenland ice sheet. Therefore, ice core ssNa+ records from the Mt. Logan region can be considered as a proxy for reconstructing the au- tumntime Aleutian Low and summertime North Pacific Subtropical High, and the ssNa+ records from Greenland ice core (20D) may provide a proxy for reconstructing the wintertime Icelandic Low.

关键词： sea-salt aerosol, ice core records, sea level pressure, subarctic regions.

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Frontal genesis of moisture atmosphere during the early 2008 persistent freezing-rain event in southern China

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Science China Earth Sciences 2010年第3期53卷 454-464页

作者： QIAN WeiHong1 & FU JiaoLan1,2 1 Department of Atmospheric Sciences, School of Physics, Peking University, beijing 100871, China 2 national meteorological center of CMA, beijing, {5., China 1. Department of Atmospheric Sciences School of Physics Peking University Beijing 100871 China2. National Meteorological Center of CMA Beijing 100081 China

From January 10 to February 2, 2008, a severe and persistent freezing-rain event occurred in southern and southwestern China. Here we use an observational analysis to compare the persistent freezing-rain event in the early 2008 with the winter precipita- tion in the late 2007 over south of the Yangtze River (Jiangnan). The persistent freezing-rain event was directly linked to the activity of quasi-stationary front. The gradient of equivalent temperature (ET) can well indicate the frontal genesis of moist atmosphere (moisture front) and its activity as well as its relationship with precipitation belt. The precipitation types (snow and freezing rains) are related to the vertical structure of moisture front. The inversion profile of ET vertical distribution is a typical synoptic condition that caused the freezing-rain event. The horizontal gradient of ET with a criterion of 10℃ / 100 km, which reflects the accumulation and release of atmospheric energy, can be applied to predict the precipitation 5.10 days in advance.

关键词： freezing-rain event frontal genesis extended-range weather forecast winter Jiangnan

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Effects of 4DVAR with multifold observed data on the typhoon track forecast

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Chinese Science Bulletin 2003年第S2期48卷 93-98页

作者： WANG Yunfeng, WANG Bin, MA GANG & WANG Yushun 1. LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences. beijing 100029, China: 2. national satellite meteorological center,{5.. China Chinese Acad Sci Inst Atmospher Phys LASG Beijing 100029 Peoples R China Natl satellite Meteorol Ctr Beijing 100081 Peoples R China

Effects of 4-dimension variational data assimi-lation (4DVAR) with multifold observed data on the typhoontrack forecast are studied, by using the MM5.3 model, theRTTOVS-5.model and their adjoint models. The data usedfor assimilation include large-scale background fields data,bogus data, cloud-derived wind data, satellite inverse data,and high resolution infrared radiation sounder data (HIRS).There are 5.typhoon cases are used to perform the numericalexperiments and assimilation experiments. The numericalresults show that with 4DVAR the initial fields can be greatlyimproved and the initial typhoon structure can be clearlydescribed.

关键词： multifold observed data 4DVAR typhoon track. DOI: 10.1360/03wd045.

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Response of remotely sensed Normalized Difference Water Deviation Index to the 2006 Drought of eastern Sichuan Basin

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Science China Earth Sciences 2008年第5期51卷 748-758页

作者： ZHANG WenJiang1, LU QiFeng2, GAO ZhiQiang3 & PENG Jian4 1 School of Water Resource and Hydropower, Sichuan University, Chengdu 610065. China 2 national satellite meteorological center, China meteorological Administration,{5., China 3 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, China 4 School of Environmental Sciences, Peking University, beijing 100871, China 1. School of Water Resource and Hydropower Sichuan University Chengdu 610065 China 2. national Statellite meteorological center China Meteorological Administration Beijing 100081 China 3. Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China 4. School of Environmental Sciences Peking University Beijing 100871 China

One of the most serious droughts in last century occurred in eastern Sichuan Basin in the summer of 2006 (hereinafter called the Drought). The response of Moderate Resolution Imaging Spectroradiometer (MODIS, boarding on NASA satellites of Terra and Aqua) to the Drought was analyzed in order to reach one practicable monitoring solution for regional soil moisture. Temporal process and spatial extension of the Drought were firstly estimated with ground meteorological and hydrological observations. Then, for the whole region of Sichuan and Chongqing, the remotely sensed Normalized Difference Water In- dex (NDWI) for the summers of 2001―2006 were calculated based on 8-day composite MODIS products, which were further used to construct a new water index (Normalized Difference Water Deviation Index, NDWDI) to examine the sensitivity of remote sensing in the Drought. The study showed that the NDWDI is more sensitive to regional drought than other absolute-soil-moisture-based indices. With the new index, the study extracted the spatial-temporal characteristics of the 2006 Drought, and explored its developing and withdrawing processes, which agreed with related statistics. Compared with ground method of drought observation, the NDWDI-based remote sensing solution of this paper is more pref- erable and practicable in that the local soil properties of water consumption and supply are implicitly taken into account, and the spatial representativity limit of ground observation is circumvented to a degree as satellite remotely senses the earth surface in a way of two-dimensional pixel matrix. So, the NDWDI-based method can be used to monitor regional soil water stress situation more practically and efficiently.

关键词： Sichuan Basin drought Normalized Difference Water Deviation Index response of remote sensing regional scale

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Cloud Climatology Characteristics of China from ISCCP Data

Cloud Climatology Characteristics of China from ISCCP Data

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第三届中日韩气象学术会议

作者： Liu Ruixia (national satellite meteorological center) Liu Yujie (national satellite meteorological center beijing 100081) Du Bingyu (Nanjing Institute of Meteorology Nanjing 210044)

＜正＞Based on the cloud amount of ISCCP D2,the spatial distribution characters and the temporal variation of cloud amount over 3 regions of China are analyzed using System cluster analysis *** we analyzed the variation trend of cloud over china and concluded that in north east of China the cloud amount increased and decreased in the west of China and in the north of *** SVD modes based on two fields between winter total cloud amount over Tibetan Plateau and summer precipitation in China are computed and credibility of teleconnection analyzed by *** result show that winter total cloud amount over Tibetan Plateau and the summer precipitation in part of north and north-east China.

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