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Change in Urban Wetlands and Their Cold Island Effects in Response to Rapid Urbanization

Chinese Geographical science 2015年第4期25卷 462-471页

作者： ZHANG Wei JIANG Jingang ZHU Yubi School of Geographical sciences Southwest University institute of remote sensing and earth sciences College of Science Hangzhou Normal University college of Economics and Management Southwest University

The cold-island effect of urban wetlands has received increasing attention in recent years due to its important role in the alleviation of urban heat ***,a representative rapidly urbanizing city with rich wetlands in China,was selected as a case study for researching the changes that the urban wetlands have undergone and their impact on the urban thermal *** surface temperature(LST) was acquired from the thermal infrared data of Landsat 5 Thematic Mapper(TM) images in 1990,1995,2000,2006,and 2010,using the single-channel *** results are as follows:1) considering the changes in land use,the urban wetlands located to the west of hangzhou have decreased significantly during 1990–2010 because of rapid *** the Xixi Wetland,the change in land use was relatively small and most of the water body and vegetation were ***,to the east of the Xixi Wetland,large areas of water body and vegetation have been replaced by built-up land as a result of the urbanization process;2) considering the change in LST,it was found from land surface temperature retrieval that the changing spatial pattern of the thermal field was highly correlated with land use *** temperature regions of the eastern Xixi Wetland were gradually eroded by high temperature regions,and the centroid of the heat island in East Xixi was found to be constantly shifting *** addition,the difference in LST between the Xixi Wetland and East Xixi has increased;3) considering the impact factors for this area,land use structure and patch shape were found to have a significant impact on LST,shown by the results of multiple linear stepwise *** the size of the wetlands in urban planning is considered to be the most effective measure in alleviating the urban heat island ***,reducing the spatial complexity of landscape patches also contributes to the alleviation of the urban heat island effect.

关键词： rapid urbanization cold island effect heat island effect Thematic Mapper(TM) Xixi Wetland hangzhou

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Comparison of SO_2 column retrievals from BRD and DOAS algorithms

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science China earth sciences 2017年第9期60卷 1694-1706页

作者： YAN HuanHuan LI XiaoJing WANG WeiHe ZHANG XingYing CHEN LiangFu HAN Dong YU Chao GAO Ling National Satellite Meteorological Center China Meteorological Administration State Key Laboratory of the science of remote sensing Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences normal college Qingdao University

Atmospheric SO_2 has a significant impact on the urban environment and global climate. Band Residual Difference Algorithm(BRD) and Differential Optical Absorption Spectroscopy(DOAS) were used respectively by NASA and ESA science team to derive SO_2 columns from satellite observations, but there are few studies on the comparison and validation of BRD and DOAS SO_2 retrievals under the same observation conditions. In this study, the radiative transfer model SCIATRAN was firstly used to validate the accuracies of BRD and DOAS SO_2 retrievals, and analyse the uncertainty of SO_2 retrieval caused by band selection,O_3 absorption, aerosol, surface reflectance, solar and viewing zenith angle. Finally, BRD and DOAS algorithms were applied to the same radiances from satellite observations, and comparisons of BRD and DOAS SO_2 retrievals were conducted over volcanic eruption and North China. Results show that, for the case with low SO_2 columns, BRD SO_2 retrievals have higher retrieval accuracy than DOAS, but typical seasonal variation with high SO_2 column in winter and low in summer can be more clearly discernible in DOAS SO_2 retrievals than BRD from satellite observations. For the case with high SO_2 columns, the differences between BRD(310.8–314.4 nm) and DOAS(315–327 nm) retrievals are large, and the value and accuracy of BRD(310.8–314.4 nm) SO_2 retrievals are lower than those of DOAS(315–327 nm) retrievals. Compared with the SO_2 inputs in forward model, both BRD(310.8–314.4 nm) and DOAS(315–327 nm) SO_2 retrievals are underestimated for the case with high SO_2 columns. The selection of wavelength range can significantly affect the accuracy of SO_2 retrieval. The error of BRD SO_2 retrieval from 310.8–314.4 nm is lower than other bands in the ultraviolet spectral region(306–327 nm). The increase of wavelength in the ultraviolet spectral region306–330 nm can reduce the underestimation of DOAS SO_2 retrievals in the case of high SO_2 column, but slight overestimation o

关键词： SO2 DOAS BRD Comparison

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Spatiotemporal changes in sunshine duration and its influential factors in Chongqing,China from 1961 to 2020

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Journal of Mountain science 2024年第6期21卷 2005-2024页

作者： LI Jun XIA Hongxuan JIANG Jinge XU Weifeng WEN Di XU Junfeng college of Geography and Tourism Chongqing Normal UniversityChongqing 401331China Key Laboratory of GIS Application of Chongqing Chongqing 401331China Chongqing Key Laboratory of earth Surface Processes and Environmental remote sensing in Three Gorges Reservoir area Chongqing 401331China institute of remote sensing and earth sciences School of Institute of Remote Sensing and Earth SciencesSchool of ScienceHangzhou Normal UniversityHangzhou 311121China

The surface solar radiation in most parts of the world has undergone a phenomenon known as global dimming and brightening,characterized by an initial decrease followed by an *** a result,the sunshine duration(SD)has decreased in the past 60 *** the backdrop of global dimming and brightening,SD has decreased to varying degrees in many regions of *** the observed data of SD,cloud amount(total cloud amount and low cloud amount,abbreviated as TCA and LCA),precipitation,and relative humidity(RH)from 34 meteorological stations in Chongqing during the period of 1961-2020,along with a digital elevation model(DEM)with a resolution of 90 m,this study analyzed the spatiotemporal variations and influencing factors of *** analysis employed methods such as linear regression,Mann-Kendall test,wavelet transformation,and DEM-based possible SD distributed *** results showed that the annual SD in Chongqing has significantly decreased over the last 60 years,with a decreasing interannual trend rate(ITR)of 40.4 h/*** for no obvious trend in spring,SD decreased significantly in summer,autumn and winter at the ITR of 21.1 h/10a,8.5 h/10a and 7.5 h/10a,*** abrupt decrease in the annual SD was found in *** difference before and after the abrupt decrease was 177.7 *** difference before and after the abrupt decrease was 177.7 *** annual SD possessed the oscillation period of *** spatial heterogeneity of the mean annual SD during the last 60 years was *** distribution of SD in Chongqing is high in the northeast and low in the *** addition,about 73%of the total area in Chongqing showed a significant and very significant decreasing *** regions with significant changes are mainly concentrated in the regions with altitudes of 200~1000 *** increasing LCA was the main cause of the decrease of the annual SD in the regions with 200-400 m altitude decreased the most and changed the *** LCA is the prim

关键词： Sunshine duration Spatiotemporal changes Mann-Kendall test Wavelet analysis Geodetector model

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Correlates of extinction risk in Chinese endemic birds

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Avian Research 2019年第2期10卷 101-110页

作者： Chuanwu Chen Di Zeng Yuhao Zhao Yiru Wu Junfeng Xu Yanping Wang Jiangsu Key Laboratory for Biodiversity and Biotechnology College of Life SciencesNanjing Normal UniversityNanjing 210023China college of Life sciences Zhejiang UniversityHangzhou 310058China institute of remote sensing and earth sciences Hangzhou Normal UniversityHangzhou 311121China

Background: China has a relative high degree of endemism of birds due to its large area, diversified topography, and varied climates and habitats. Among the 77 Chinese endemic birds, 29 species are classified as threatened according to the officially released China Biodiversity Red List in 2015. Chinese endemic birds should be the focus of conservation because their local extinction in China means complete global extinction. However, to date, no study has explicitly examined the patterns and processes of extinction and threat in Chinese endemic birds. Methods: We obtained eleven biological traits and four extrinsic factors that are commonly hypothesized to influence extinction risk. After phylogenetic correction, these factors were used separately and in combination to assess their associations with extinction risk. Results: We found that 37.7% of Chinese endemic birds were listed as threatened (Vulnerable, Endangered and Critically Endangered). Small range size, high hunting vulnerability, and high human population density were important predictors of high extinction risk in Chinese endemic birds. Conclusions: Our study is the first to systematically investigate the patterns and processes of extinction risk in Chinese endemic birds. We suggest that endemic species with small range size and living in area with high human densities require conservation priorities. Conservation efforts should also focus on the reduction of human threats, such as human hunting and habitat degradation, for the effective preservation of Chinese endemic birds.

关键词： Comparative analysis Endemic birds Geographic range size Human population density Hunting vulnerability Proactive conservation Red list

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URBANIZATION EFFECTS ON OBSERVED CHANGES IN SUMMER EXTREME HEAT EVENTS OVER ZHEJIANG PROVINCE, EAST CHINA

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Journal of Tropical Meteorology 2015年第3期21卷 295-302页

作者：杨续超陈锋祝炜平滕卫平 Ocean college Zhejiang university Zhejiang institute of Meteorological sciences institute of remote sensing and earth sciences college of science hangzhou normal university Zhejiang Provincial Key Laboratory of Urban Wetlands and Regional Change

Although the urban heat island(UHI) is a well-documented phenomenon, relatively little information in the literature is available about its impact on summer extreme heat event(EHE). As UHI is characterized by increased temperature, it can potentially increase the magnitude and duration of EHEs within cities. Based on daily maximum temperature records from 62 observation stations in Zhejiang province from the period 1971-2011 and satellite-measured nighttime light imagery from the Defense Meteorological Satellite Program(DMSP) Operational Linescan System(OLS) during 1992-2010, we analyzed the long-term change of summer EHEs and its association with the rapid urbanization process. The results could be concluded as follows:(1) Zhejiang has experienced rapid urbanization and dramatic growth in urban areas in the past two decades, especially after 2000.(2) The summer mean maximum temperature and the 95 th percentile of summer daily maximum temperature in most of its stations have increased, with the most significant increase occurring in the highly urbanized areas including the city belt around hangzhou Bay, Taizhou-Wenzhou and Jinghua-Yiwu city belts.(3) The hot days and hot-day degrees, defined by both daily 95 th percentile and the threshold of 35℃, show that the UHI effect causes additional hot days and heat stress in urban stations compared to rural *** results in this study suggest that the UHI effect should be determined and incorporated in preparing high temperature forecasts in cities.

关键词： urbanization urban heat island extreme heat event nighttime light Zhejiang province

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Detecting Agro-Droughts in Southwest of China Using MODIS Satellite Data

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Journal of Integrative Agriculture 2013年第1期12卷 159-168页

作者： ZHANG Feng ZHANG Li-wen WANG Xiu-zhen HUNG Jing-feng institute of Agricultural remote sensing & Information Application Zhejiang University Key Laboratory of Environmental Remediation and Ecological Health Ministry of Education/College of Natural Resources and Environmental Science Zhejiang University institute of remote sensing and earth sciences Hangzhou Normal University The Provinical Key Laboratories of Agricultural remote sensing and Information System Zhejiang Province

The normalized difference vegetation index （NDVI） has proven to be typically employed to assess terrestrial vegetation conditions. However, one limitation of NDVI for drought monitoring is the apparent time lag between rainfall deficit and NDVI response. To better understand this relationship, time series NDVI （2000-2010） during the growing season in Sichuan Province and Chongqing City were analyzed. The vegetation condition index （VCI） was used to construct a new drought index, time-integrated vegetation condition index （TIVCI）, and was then compared with meteorological drought indices-standardized precipitation index （SPI）, a multiple-time scale meteorological-drought index based on precipitation, to examine the sensitivity on droughts. Our research findings indicate the followings：（1） farmland NDVI sensitivity to precipitation in study area has a time lag of 16-24 d, and it maximally responds to the temperature with a lag of about 16 d. （2） We applied the approach to Sichuan Province and Chongqing City for extreme drought monitoring in 2006 and 2003, and the results show that the monitoring results from TIVCI are closer to the published China agricultural statistical data than VCI. Compared to VCI, the best results from TIVCI3 were found with the relative errors of -4.5 and 6.36% in 2006 for drought affected area and drought disaster area respectively, and 5.11 and -5.95% in 2003. （3） Compared to VCI, TIVCI has better correlation with the SPI, which indicates the lag and cumulative effects of precipitation on vegetation. Our finding proved that TIVCI is an effective indicator of drought detection when the time lag effects between NDVI and climate factors are taken into consideration.

关键词： time-integrated vegetation condition index (TIVCI) time lag normalized difference vegetation index (NDVI) drought monitor standardized precipitation index (SPI)

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Monitoring nitrogen concentration of oilseed rape from hyperspectral data using radial basis function

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International Journal of Digital earth 2013年第6期6卷 550-562页

作者： Fumin Wang Jingfeng Huang Yuan Wang Zhuanyu Liu Dailiang Peng Feifeng Cao institute of Hydrology and Water Resources Zhejiang UniversityHangzhouChina institute of Agricultural remote sensing&Information Application Zhejiang UniversityHangzhouChina institute of remote sensing and earth sciences Hangzhou Normal UniversityHangzhouChina Center for earth Observation and Digital earth Chinese Academy of SciencesBeijingChina Bureau of Water Resources and Hydropower Engineering of Zhejiang Provinces HangzhouChina

remote sensing technology is the important tool of digital earth,it can facilitate nutrient management in sustainable cropping *** the study,two types of radial basis function(RBF)neural network approaches,the standard radial basis function(SRBF)neural networks and the modified type of RBF,generalized regression neural networks(GRNN),were investigated in estimating the nitrogen concentrations of oilseed rape canopy using vegetation indices(VIs)and hyperspectral *** analyses were performed to the spectral variables and the *** Root Mean Square Error(RMSE)and determination coefficients(R2)were used to assess their predictability of nitrogen *** all spectral variables(VIs and hyperspectral reflectance),the GRNN method produced more accurate estimates of nitrogen concentrations than did the SRBF method at all ranges of nitrogen concentrations,and the better agreements between the measured and the predicted nitrogen concentration were obtained with the GRNN *** indicated that the GRNN method is prior to the SRBF method in estimation of nitrogen *** the VIs,the Modified Chlorophyll Absorption in Reflectance Index(MCARI),MCARI1510,and Transformed Chlorophyll Absorption in Reflectance Index are better than the others in estimating oilseed rape canopy nitrogen *** to the results from VIs,the hyperspectral reflectance data also gave an acceptable *** study showed that nitrogen concentrations of oilseed rape canopy could be monitored using remotely sensed data and the RBF method,especially the GRNN method,is a useful explorative tool for oilseed rape nitrogen concentration monitoring when applied on hyperspectral data.

关键词： vegetation indices hyperspectral data nitrogen concentration artifi-cial neural network radial basis function agriculture remote sensing

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Cold Damage Risk Assessment of Double Cropping Rice in Hunan, China

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Journal of Integrative Agriculture 2013年第2期12卷 352-363页

作者： CHENG Yong-xiang HUANG Jing-feng HAN Zhong-ling GUO Jian-ping ZHAO Yan-xia WANG Xiu-zhen GUO Rui-fang institute of remote sensing and Information Application Zhejiang University Key Laboratory of Polluted Environment Remediation and Ecological Health Ministry of Education/College of Natural Resources and Environmental Science Zhejiang University college of Life science Shihezi University The Provinical Key Laboratory of Agricultural remote sensing and Information System institute of Information and Technology Shihezi University Chinese Academy of Meteorological science institute of remote sensing and earth sciences Hangzhou Normal University

Combined with remote sensing data and meteorological data, cold damage risk was assessed for planting area of double cropping rice （DCR） in Hunan Province, China. A new methodology of cold damage risk assessment was built that apply to grid and have clear hazard-affected body. Each station cold damage annual frequency and average annual intensity of cold damage was calculated by using 1951-2010 station daily mean temperature and simple cold damage identification index. On this basis, average annual cold damage risk index was obtained by their product. The spatial analysis models of cold damage risk index about double-season early rice （DSER） and double-season later rice （DSLR） were established respectively by the relation of average annual cold damage risk index and its geographic factors. Critical threshold of level of average annual cold damage risk index for DSER and DSLR were respectively divided by the correlative equation of cold damage annual frequency and average annual intensity of cold damage. 2001-2010 planting area of DCR, acquired by time series analysis of MOD09AI 8-d composite land surface reflectance product, was as target of assessment. The results show average annual intensity of cold damage is exponential function of cold damage annual frequency, average annual cold damage risk index is directly proportional to cold damage cumulant and cold damage annual frequency, and is inversely proportional to happen times of cold damage and the square of statistical time sequence length. Cold damage risk of DSER is higher than DSLR in Hunan Province. In the 10-yr stacking map, DCR planting in low risk area accounted for 11.92% of total extraction area, in moderate risk area accounted for 69.62%, in high risk area accounted for 18.46%. According to the cold damage risk assessment result, DCR production can be guided to reduce cold damage losses.

关键词： double cropping rice cold damage risk assessment

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Preliminary evaluation of the long-term GLASS albedo product

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International Journal of Digital earth 2013年第S01期6卷 69-95页

作者： Qiang Liua Lizhao Wang Ying Qu Nanfeng Liu Suhong Liu Hairong Tang Shunlin Liang college of Global Change and earth System science Beijing Normal UniversityBeijingChina State Key Laboratory of remote sensing science Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing Applications of Chinese Academy of SciencesBeijingChina institute of remote sensing Applications Chinese Academy of SciencesBeijingChina School of Geography Beijing Normal UniversityBeijingChina institute of Electronics Chinese Academy of SciencesBeijingChina Department of Geographical sciences University of MarylandCollege ParkMDUSA

Land surface albedo is an important parameter to describe the radiant forcing in the climate system.A long-time series of global albedo products is needed to understand the mechanism of climate *** to support global change and earth system studies,GLASS(Global LAnd Surface Satellites)provides long-term global land surface albedo product from 1981 to 2010,which are generated from multisource remote sensing data and newly developed *** is critical to assess the quality of the GLASS product when it is released to the *** paper first introduced the algorithms and then analyzed the integrity,accuracy,and robustness of the GLASS albedo *** results show that the GLASS albedo product is a gapless,long-term continuous,and self-consistent data-set with an accuracy similar to that of the widely acknowledged MODIS MCD43 *** quality flag,which is provided along with the black-sky and white-sky albedo,gives a pertinent indication of the expected uncertainty in the product.

关键词： land surface broadband albedo validation GLASS MODIS

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Effects of polarization calibration on aerosol optical depth retrieval: An ocean case sensitivity analysis

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science China earth sciences 2015年第6期58卷 939-948页

作者： LIU TianYue CHI TianHe CHEN Wei institute of remote sensing and Digital earth Chinese Academy of Sciences college of earth sciences University of Chinese Academy of Sciences college of Geoscience and Surveying Engineering China University of Mining and Technology

Reflectance measurements of both the visible and infrared bands of passive remote sensing sensors are widely used to retrieve aerosol optical depth(AOD) information. This is performed commonly for data obtained over both ocean and land, and these measurements allow for the off line development of a lookup table using radiative transfer models. Owing to molecular and aerosol effects, the reflected light received by the sensor is usually highly polarized. The linear polarization effect may be up to 100%, and the polarization factor of a sensor optical system will change the total intensity as well as the polarization status of the signal reaching the detector. The detector response will be different when the incident light polarization status changes, even if the total intensity remains constant. However, if the polarization calibration is neglected, it will cause obvious errors in the aerosol data retrieval. This is especially true for aerosol optical depth retrieval over an ocean. This measurement relies directly on the reflectance output of the sensor. Cases involving land surfaces are not discussed herein because the inhomogeneous properties conceal the error due to polarization. Taking the 550 and 860 nm bands as examples, the difference between the real top-of-atmosphere(TOA) reflectance and the reflectance reaching the detector is calculated using three different sensor polarization standards according to the Sea-viewing Wide Field-of-view Sensor(Sea Wi FS) and Moderate Resolution Imaging Spectroradiometer(MODIS) standards. The differences in AOD retrieval are also demonstrated using the lookup table developed previously from a vector radiative transfer code. The results reveal that under a normal situation in which the AOD is 0.15, the maximum AOD retrieval error could reach 0.04 in 550 nm but only 0.02 in 860 nm for the dust aerosol model. For the soot aerosol model, the maximum AOD retrieval error is 0.1 in 550 nm and 0.12 in 860 nm, indicating that the lack

关键词： aerosol polarization calibration radiative transfer

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