limin yang | South Dakota State University (original) (raw)

Papers by limin yang

Research paper thumbnail of United States national land cover data base development 1992–2001 and beyond

2008 International Workshop on Earth Observation and Remote Sensing Applications, 2008

ABSTRACT An accurate, up-to-date and spatially-explicate national land cover database is required... more ABSTRACT An accurate, up-to-date and spatially-explicate national land cover database is required for monitoring the status and trends of the nationpsilas terrestrial ecosystem, and for managing and conserving land resources at the national scale. With all the challenges and resources required to develop such a database, an innovative and scientifically sound planning must be in place and a partnership be formed among users from government agencies, research institutes and private sectors. In this paper, we summarize major scientific and technical issues regarding the development of the NLCD 1992 and 2001. Experiences and lessons learned from the project are documented with regard to project design, technical approaches, accuracy assessment strategy, and project implementation. Future improvements in developing next generation NLCD beyond 2001 are suggested, including: (1) enhanced satellite data preprocessing in correction of atmospheric and adjacency effect and the topographic normalization; (2) improved classification accuracy through comprehensive and consistent training data and new algorithm development; (3) multi-resolution and multitemporal database targeting major land cover changes and land cover database updates; (4) enriched database contents by including additional biophysical parameters and/or more detailed land cover classes through synergizing multi-sensor, multi-temporal, and multi-spectral satellite data and ancillary data, and (5) transform the NLCD project into a national land cover monitoring program.

Research paper thumbnail of Completion of the 2006 National Land Cover Database for the conterminous United States. Photo Eng Remote Sens

Photogrammetric Engineering and Remote Sensing

Research paper thumbnail of Applicability of Landsat ETM+ SLC-off Imagery Filled using the Neighborhood Similar Pixel Interpolator for Change Detection

The scan-line corrector (SLC) of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) failed in 200... more The scan-line corrector (SLC) of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) failed in 2003, which seriously limited scientific applications of ETM+ data. A method called the Neighborhood Similar Pixel Interpolator (NSPI) was developed to interpolate the values of the pixels within the gaps. This method is based on the assumption that the same-class neighboring pixels around the un-scanned pixels have similar spectral characteristics and that these neighboring and un-scanned pixels exhibit similar patterns of spectral differences between dates. Previous study indicates that NSPI performs well for filling image data gaps, even across heterogeneous landscapes. This study evaluated the applicability and effectiveness of using the NSPI-filled SLC-off ETM+ images for change detection. Six Landsat path/rows representing a variety of landscapes with different types of dominant disturbances were selected, and an SLC-on image pair was obtained for each path/row. A simulated SLC-off im...

Research paper thumbnail of Evaluation of Grassland Dynamics in the Northern-Tibet Plateau of China Using Remote Sensing and Climate Data

Research paper thumbnail of DEVELOPMENT OF THE UNITED STATES NATIONAL LAND COVER DATABASE: EXPERIENCE FROM 1992 AND 2001 IMPLEMENTATION

The Multi-Resolution Land Characteristics (MRLC) Consortium is a group formed by the U.S. federal... more The Multi-Resolution Land Characteristics (MRLC) Consortium is a group formed by the U.S. federal agencies in 1990 to purchase Landsat 5 Thematic Mapper imagery for the conterminous U.S. and to develop a National Land Cover Dataset (NLCD 1992). The NLCD 1992 was completed in 2000. In 1999, a second-generation MRLC (MRLC 2001) consortium was formed to purchase three dates of Landsat 7 Thematic Mapper Plus (and some Landsat 5) imagery for the entire United States and to coordinate the production of a comprehensive National Land Cover Database (NLCD 2001). The NLCD 2001 was completed in April 2008.The NLCD 1992 and NLCD 2001 are specifically designed to meet the needs of the U.S. federal agencies for nationally consistent satellite remote sensing and land cover database. In addition, the MRLC consortium provides the database as public domain information. This paper summarizes the philosophy and scientific and technical issues with regard to design and implementation of the NLCD 1992 an...

Research paper thumbnail of Analysis of Urban/rural Spatial Surface Energy Exchanges Using a Numerical Model and Satellite Data

Current urban/rural surface energy balance simulations using boundary layer climate models have b... more Current urban/rural surface energy balance simulations using boundary layer climate models have been found to be inaccurate, especially in modeled turbulent heat fluxes and surface longwave radiation. The weakness is primarily due to unreliable input data with regard to surface thermal and radiative properties utilized by the models. This study developed a new parameterization for evaluating regional surface moisture availability by use of concurrently-acquired satellite and surface meteorological measurements. The study also evaluated regional surface albedo using satellite data. Furthermore, a procedure was designed to integrate the satellite-derived surface parameters with a boundary layer climate model for simulating spatial surface energy exchange. The new parameterization and procedures were tested through spatial surface energy balance simulation of an urban/rural landscape in southeastern Nebraska. The modeled surface temperature and net radiation were compared to those deri...

Research paper thumbnail of Characterizing Woody Vegetation Spectral and Structural Parameters with a 3-D Scene Model

Quantification of structural and biophysical parameters of woody vegetation is of great significa... more Quantification of structural and biophysical parameters of woody vegetation is of great significance in understanding vegetation condition, dynamics and functionality. Such information over a landscape scale is crucial for global and regional land cover characterization, global carbon-cycle research, forest resource inventories, and fire fuel estimation. While great efforts and progress have been made in mapping general land cover types over large area, at present, the ability to quantify regional woody vegetation structural and biophysical parameters is limited. One approach to address this research issue is through an integration of physically based 3-D scene model with multiangle and multispectral remote sensing data and in-situ measurements. The first step of this work is to model woody vegetation structure and its radiation regime using a physically based 3-D scene model and field data, before a robust operational algorithm can be developed for retrieval of important woody vege...

Research paper thumbnail of Improving Vegetation Classification using EOS MISR and MODIS Data

The relationship between surface Bidirectional Reflectance Factor (BRF) and vegetation properties... more The relationship between surface Bidirectional Reflectance Factor (BRF) and vegetation properties is complex and varies with the degree of heterogeneity and architecture of a vegetation canopy. Research has demonstrated that surface BRF pattern is detectable from airborne or spaceborne multi-angle and multi-spectral observations. However, application in large-area vegetation characterization using spaceborne multi-angle remote sensing data is still in its infancy. The primary motivation of this study was to test if and to what extent vegetation classification can be improved through a data mining technique using multi-spectral, multi-temporal and multi-angle data (MISR and MODIS) in a semi-arid environment in the United States. The study area is around the Jornada Rangeland in New Mexico, USA with grassland, shrubland, woodland and some desert barren land. Satellite data used for this study include MISR surface BRF and the MODIS 16-day composite NDVI data from year 2002 (all resampl...

Research paper thumbnail of A Multi-Index Integrated Change Detection Method for Updating the National Land Cover Database

Land cover change is typically captured by comparing two or more dates of imagery and associating... more Land cover change is typically captured by comparing two or more dates of imagery and associating spectral change with true thematic change. A new change detection method, Multi-Index Integrated Change (MIIC), has been developed to capture a full range of land cover disturbance patterns for updating the National Land Cover Database (NLCD). Specific indices typically specialize in identifying only certain types of disturbances; for example, the Normalized Burn Ratio (NBR) has been widely used for monitoring fire disturbance. Recognizing the potential complementary nature of multiple indices, we integrated four indices into one model to more accurately detect true change between two NLCD time periods. The four indices are NBR, Normalized Difference Vegetation Index (NDVI), Change Vector (CV), and a newly developed index called the Relative Change Vector (RCV). The model is designed to provide both change location and change direction (e.g. biomass increase or biomass decrease). The in...

Research paper thumbnail of The impact of urbanization on the monthly averaged diurnal cycle in October 2004 in the Pearl River Delta region

Atmosfera

The Pearl River Delta (PRD) region in southern China has experienced rapid urbanization and drama... more The Pearl River Delta (PRD) region in southern China has experienced rapid urbanization and dramatic economic growth in last 25 years. Using identical observed meteorology for lateral boundary conditions, two one-month simulations were conducted: one using the original United States Geological Survey (USGS) 24-category land cover data (namely NU) and the other using the urban land cover data from 2004 Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images (namely HU) as lower boundary conditions in a mesoscale model. October 2004 was chosen for simulation due to no precipitation in the Pearl River Delta corresponding to drought conditions. The spatially averaged value (domain-averaged, land-averaged value, urban-averaged value) used for the analysis can reflect the regional climate over an area of several hundreds of kilometers. The simulation results show that the additional urbanization in the PRD amplifies the spatially averaged diurnal cycle of surface temperatur...

Research paper thumbnail of Land Cover Classification in the Poyang Lake Region, China, Using Landsat TM and JERS-1 Synthetic Aperture Radar Data

Research paper thumbnail of Regional Forest Land Cover Characterisation using Medium Spatial Resolution Satellite Data

Remote Sensing of Forest Environments, 2003

... 2000 pilot study, we tried to address this problem by using scene identification number as an... more ... 2000 pilot study, we tried to address this problem by using scene identification number as an input to the decision tree program, and ... 404 Regional forest land cover characterisation using medium spatial resolution satellite data 5.2 Classification algorithm selection The ...

Research paper thumbnail of Combining Accuracy Assessment of Land-Cover Maps With Environmental Monitoring Programs

Monitoring Ecological Condition in the Western United States, 2000

Research paper thumbnail of Validating the Modified Perpendicular Drought Index in the North China Region Using <italic>In Situ</italic> Soil Moisture Measurement

IEEE Geoscience and Remote Sensing Letters, 2015

ABSTRACT Soil moisture content is one of the most important variables for monitoring and assessin... more ABSTRACT Soil moisture content is one of the most important variables for monitoring and assessing the drought condition. In this letter, a modified perpendicular drought index (MPDI) derived from the Moderate Resolution Imaging Spectroradiometer satellite data was validated using in situ soil moisture measurements in Henan province of North China. The soil moisture at different depths of a soil layer and time lag on usefulness of the MPDI for estimating soil moisture content was analyzed; the effectiveness of the MPDI was evaluated with the observed soil moisture content and the comprehensive drought index KKK for different soil types. The results showed that the MPDI was significantly correlated with soil moisture content for the top soil layer with 10 cm depth. For a time lag ranging from 0 to 4 days, the correlation of MPDI to soil moisture was significant with no time lag in the depth of top 10 cm (r=−0.867)(r = -0.867)(r=0.867). For the stations of the same soil texture type of loam, the correlation coefficient between MPDI and soil moisture is higher than that of all soil texture types. In a regional scale, the MPDI reflected an obvious spatial pattern of drought under different growing stages in the drought years over the study area.

Research paper thumbnail of Analysis of Canopy Cover and Impervious Surface Cover of Zone 41

Research paper thumbnail of Recent experiences in mapping land cover from AVHRR data: People's Republic of China test sites

Land cover types of two test sites in the north central and southeast China were mapped using NOA... more Land cover types of two test sites in the north central and southeast China were mapped using NOAA AVHRR 1-km NDVI data. For major land cover types, the results from this study compared favorably with the existing land use/cover maps of China. However, identification of detailed land cover types in certain study areas was difficult due to extremely complex and fragmented land use/cover patterns and the effect of cloud contamination on NDVI data. Use of ancillary data such as DEM and soil types was effective in post-classification and improved the quality of results

Research paper thumbnail of A numerical study of the influence of urban expansion on monthly climate in dry autumn over the Pearl River Delta, China

Theoretical and Applied Climatology, 2007

... For instance, Grossman-Clarke et al. (2005) perform-ed a 72-h simulation to investigate the i... more ... For instance, Grossman-Clarke et al. (2005) perform-ed a 72-h simulation to investigate the influence of land cover changes with urbanization on sur-face energy budget, near ... The PearlRiver Delta (PRD) region is located in south China with population of more than Fig. ...

Research paper thumbnail of A numerical study of influences of urban land-use change on ozone distribution over the Pearl River Delta region, China

Research paper thumbnail of Estimation of urban energy heat flux and anthropogenic heat discharge using aster image and meteorological data: case study in Beijing metropolitan area

Journal of Applied Remote Sensing, 2012

ABSTRACT In order to analyze the mechanism of the urban heat island, it is paramount and meaningf... more ABSTRACT In order to analyze the mechanism of the urban heat island, it is paramount and meaningful to estimate the anthropogenic heat flux in cities. A case study was carried out to study the energy balance process in Beijing, China, based on a canopy energy balance equation and to estimate the urban energy fluxes and anthropogenic heat discharge and their seasonal and spatial variations. Two ASTER images and meteorological observation data from the winter and summer seasons were used for the study. The results showed that: (1) in Beijing, the anthropogenic heat discharge flux reached a maximum of 163.76 W m-2 in winter and 288.26 W m-2 in summer. Spatially, the magnitude of the flux was significantly affected by urban land cover types. In winter, the highest value occurred at an urban commercial district with an average value of 47.60 W m-2. In summer, the highest value occurred at the airport and the industrial areas with the regional average reaching 47.29 W m-2 the spatial pattern of the heat discharge appears to be clustered, with some, localized high-accumulation centers such as in industrial areas and commercial districts. (2) The anthropogenic discharge was one of the important contributors to the surface-atmosphere energy exchange in cities. The heat discharge had a positive effect on elevating the surface temperature and formation of the urban heat island, especially in the summer. The study confirms the importance to account for the impact of the anthropogenic heat flux on urban energy budget.

Research paper thumbnail of A surface acoustic wave humidity sensor based on electrosprayed silicon-containing polyelectrolyte

Sensors and Actuators B: Chemical, 2010

Research paper thumbnail of United States national land cover data base development 1992–2001 and beyond

2008 International Workshop on Earth Observation and Remote Sensing Applications, 2008

ABSTRACT An accurate, up-to-date and spatially-explicate national land cover database is required... more ABSTRACT An accurate, up-to-date and spatially-explicate national land cover database is required for monitoring the status and trends of the nationpsilas terrestrial ecosystem, and for managing and conserving land resources at the national scale. With all the challenges and resources required to develop such a database, an innovative and scientifically sound planning must be in place and a partnership be formed among users from government agencies, research institutes and private sectors. In this paper, we summarize major scientific and technical issues regarding the development of the NLCD 1992 and 2001. Experiences and lessons learned from the project are documented with regard to project design, technical approaches, accuracy assessment strategy, and project implementation. Future improvements in developing next generation NLCD beyond 2001 are suggested, including: (1) enhanced satellite data preprocessing in correction of atmospheric and adjacency effect and the topographic normalization; (2) improved classification accuracy through comprehensive and consistent training data and new algorithm development; (3) multi-resolution and multitemporal database targeting major land cover changes and land cover database updates; (4) enriched database contents by including additional biophysical parameters and/or more detailed land cover classes through synergizing multi-sensor, multi-temporal, and multi-spectral satellite data and ancillary data, and (5) transform the NLCD project into a national land cover monitoring program.

Research paper thumbnail of Completion of the 2006 National Land Cover Database for the conterminous United States. Photo Eng Remote Sens

Photogrammetric Engineering and Remote Sensing

Research paper thumbnail of Applicability of Landsat ETM+ SLC-off Imagery Filled using the Neighborhood Similar Pixel Interpolator for Change Detection

The scan-line corrector (SLC) of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) failed in 200... more The scan-line corrector (SLC) of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) failed in 2003, which seriously limited scientific applications of ETM+ data. A method called the Neighborhood Similar Pixel Interpolator (NSPI) was developed to interpolate the values of the pixels within the gaps. This method is based on the assumption that the same-class neighboring pixels around the un-scanned pixels have similar spectral characteristics and that these neighboring and un-scanned pixels exhibit similar patterns of spectral differences between dates. Previous study indicates that NSPI performs well for filling image data gaps, even across heterogeneous landscapes. This study evaluated the applicability and effectiveness of using the NSPI-filled SLC-off ETM+ images for change detection. Six Landsat path/rows representing a variety of landscapes with different types of dominant disturbances were selected, and an SLC-on image pair was obtained for each path/row. A simulated SLC-off im...

Research paper thumbnail of Evaluation of Grassland Dynamics in the Northern-Tibet Plateau of China Using Remote Sensing and Climate Data

Research paper thumbnail of DEVELOPMENT OF THE UNITED STATES NATIONAL LAND COVER DATABASE: EXPERIENCE FROM 1992 AND 2001 IMPLEMENTATION

The Multi-Resolution Land Characteristics (MRLC) Consortium is a group formed by the U.S. federal... more The Multi-Resolution Land Characteristics (MRLC) Consortium is a group formed by the U.S. federal agencies in 1990 to purchase Landsat 5 Thematic Mapper imagery for the conterminous U.S. and to develop a National Land Cover Dataset (NLCD 1992). The NLCD 1992 was completed in 2000. In 1999, a second-generation MRLC (MRLC 2001) consortium was formed to purchase three dates of Landsat 7 Thematic Mapper Plus (and some Landsat 5) imagery for the entire United States and to coordinate the production of a comprehensive National Land Cover Database (NLCD 2001). The NLCD 2001 was completed in April 2008.The NLCD 1992 and NLCD 2001 are specifically designed to meet the needs of the U.S. federal agencies for nationally consistent satellite remote sensing and land cover database. In addition, the MRLC consortium provides the database as public domain information. This paper summarizes the philosophy and scientific and technical issues with regard to design and implementation of the NLCD 1992 an...

Research paper thumbnail of Analysis of Urban/rural Spatial Surface Energy Exchanges Using a Numerical Model and Satellite Data

Current urban/rural surface energy balance simulations using boundary layer climate models have b... more Current urban/rural surface energy balance simulations using boundary layer climate models have been found to be inaccurate, especially in modeled turbulent heat fluxes and surface longwave radiation. The weakness is primarily due to unreliable input data with regard to surface thermal and radiative properties utilized by the models. This study developed a new parameterization for evaluating regional surface moisture availability by use of concurrently-acquired satellite and surface meteorological measurements. The study also evaluated regional surface albedo using satellite data. Furthermore, a procedure was designed to integrate the satellite-derived surface parameters with a boundary layer climate model for simulating spatial surface energy exchange. The new parameterization and procedures were tested through spatial surface energy balance simulation of an urban/rural landscape in southeastern Nebraska. The modeled surface temperature and net radiation were compared to those deri...

Research paper thumbnail of Characterizing Woody Vegetation Spectral and Structural Parameters with a 3-D Scene Model

Quantification of structural and biophysical parameters of woody vegetation is of great significa... more Quantification of structural and biophysical parameters of woody vegetation is of great significance in understanding vegetation condition, dynamics and functionality. Such information over a landscape scale is crucial for global and regional land cover characterization, global carbon-cycle research, forest resource inventories, and fire fuel estimation. While great efforts and progress have been made in mapping general land cover types over large area, at present, the ability to quantify regional woody vegetation structural and biophysical parameters is limited. One approach to address this research issue is through an integration of physically based 3-D scene model with multiangle and multispectral remote sensing data and in-situ measurements. The first step of this work is to model woody vegetation structure and its radiation regime using a physically based 3-D scene model and field data, before a robust operational algorithm can be developed for retrieval of important woody vege...

Research paper thumbnail of Improving Vegetation Classification using EOS MISR and MODIS Data

The relationship between surface Bidirectional Reflectance Factor (BRF) and vegetation properties... more The relationship between surface Bidirectional Reflectance Factor (BRF) and vegetation properties is complex and varies with the degree of heterogeneity and architecture of a vegetation canopy. Research has demonstrated that surface BRF pattern is detectable from airborne or spaceborne multi-angle and multi-spectral observations. However, application in large-area vegetation characterization using spaceborne multi-angle remote sensing data is still in its infancy. The primary motivation of this study was to test if and to what extent vegetation classification can be improved through a data mining technique using multi-spectral, multi-temporal and multi-angle data (MISR and MODIS) in a semi-arid environment in the United States. The study area is around the Jornada Rangeland in New Mexico, USA with grassland, shrubland, woodland and some desert barren land. Satellite data used for this study include MISR surface BRF and the MODIS 16-day composite NDVI data from year 2002 (all resampl...

Research paper thumbnail of A Multi-Index Integrated Change Detection Method for Updating the National Land Cover Database

Land cover change is typically captured by comparing two or more dates of imagery and associating... more Land cover change is typically captured by comparing two or more dates of imagery and associating spectral change with true thematic change. A new change detection method, Multi-Index Integrated Change (MIIC), has been developed to capture a full range of land cover disturbance patterns for updating the National Land Cover Database (NLCD). Specific indices typically specialize in identifying only certain types of disturbances; for example, the Normalized Burn Ratio (NBR) has been widely used for monitoring fire disturbance. Recognizing the potential complementary nature of multiple indices, we integrated four indices into one model to more accurately detect true change between two NLCD time periods. The four indices are NBR, Normalized Difference Vegetation Index (NDVI), Change Vector (CV), and a newly developed index called the Relative Change Vector (RCV). The model is designed to provide both change location and change direction (e.g. biomass increase or biomass decrease). The in...

Research paper thumbnail of The impact of urbanization on the monthly averaged diurnal cycle in October 2004 in the Pearl River Delta region

Atmosfera

The Pearl River Delta (PRD) region in southern China has experienced rapid urbanization and drama... more The Pearl River Delta (PRD) region in southern China has experienced rapid urbanization and dramatic economic growth in last 25 years. Using identical observed meteorology for lateral boundary conditions, two one-month simulations were conducted: one using the original United States Geological Survey (USGS) 24-category land cover data (namely NU) and the other using the urban land cover data from 2004 Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images (namely HU) as lower boundary conditions in a mesoscale model. October 2004 was chosen for simulation due to no precipitation in the Pearl River Delta corresponding to drought conditions. The spatially averaged value (domain-averaged, land-averaged value, urban-averaged value) used for the analysis can reflect the regional climate over an area of several hundreds of kilometers. The simulation results show that the additional urbanization in the PRD amplifies the spatially averaged diurnal cycle of surface temperatur...

Research paper thumbnail of Land Cover Classification in the Poyang Lake Region, China, Using Landsat TM and JERS-1 Synthetic Aperture Radar Data

Research paper thumbnail of Regional Forest Land Cover Characterisation using Medium Spatial Resolution Satellite Data

Remote Sensing of Forest Environments, 2003

... 2000 pilot study, we tried to address this problem by using scene identification number as an... more ... 2000 pilot study, we tried to address this problem by using scene identification number as an input to the decision tree program, and ... 404 Regional forest land cover characterisation using medium spatial resolution satellite data 5.2 Classification algorithm selection The ...

Research paper thumbnail of Combining Accuracy Assessment of Land-Cover Maps With Environmental Monitoring Programs

Monitoring Ecological Condition in the Western United States, 2000

Research paper thumbnail of Validating the Modified Perpendicular Drought Index in the North China Region Using <italic>In Situ</italic> Soil Moisture Measurement

IEEE Geoscience and Remote Sensing Letters, 2015

ABSTRACT Soil moisture content is one of the most important variables for monitoring and assessin... more ABSTRACT Soil moisture content is one of the most important variables for monitoring and assessing the drought condition. In this letter, a modified perpendicular drought index (MPDI) derived from the Moderate Resolution Imaging Spectroradiometer satellite data was validated using in situ soil moisture measurements in Henan province of North China. The soil moisture at different depths of a soil layer and time lag on usefulness of the MPDI for estimating soil moisture content was analyzed; the effectiveness of the MPDI was evaluated with the observed soil moisture content and the comprehensive drought index KKK for different soil types. The results showed that the MPDI was significantly correlated with soil moisture content for the top soil layer with 10 cm depth. For a time lag ranging from 0 to 4 days, the correlation of MPDI to soil moisture was significant with no time lag in the depth of top 10 cm (r=−0.867)(r = -0.867)(r=0.867). For the stations of the same soil texture type of loam, the correlation coefficient between MPDI and soil moisture is higher than that of all soil texture types. In a regional scale, the MPDI reflected an obvious spatial pattern of drought under different growing stages in the drought years over the study area.

Research paper thumbnail of Analysis of Canopy Cover and Impervious Surface Cover of Zone 41

Research paper thumbnail of Recent experiences in mapping land cover from AVHRR data: People's Republic of China test sites

Land cover types of two test sites in the north central and southeast China were mapped using NOA... more Land cover types of two test sites in the north central and southeast China were mapped using NOAA AVHRR 1-km NDVI data. For major land cover types, the results from this study compared favorably with the existing land use/cover maps of China. However, identification of detailed land cover types in certain study areas was difficult due to extremely complex and fragmented land use/cover patterns and the effect of cloud contamination on NDVI data. Use of ancillary data such as DEM and soil types was effective in post-classification and improved the quality of results

Research paper thumbnail of A numerical study of the influence of urban expansion on monthly climate in dry autumn over the Pearl River Delta, China

Theoretical and Applied Climatology, 2007

... For instance, Grossman-Clarke et al. (2005) perform-ed a 72-h simulation to investigate the i... more ... For instance, Grossman-Clarke et al. (2005) perform-ed a 72-h simulation to investigate the influence of land cover changes with urbanization on sur-face energy budget, near ... The PearlRiver Delta (PRD) region is located in south China with population of more than Fig. ...

Research paper thumbnail of A numerical study of influences of urban land-use change on ozone distribution over the Pearl River Delta region, China

Research paper thumbnail of Estimation of urban energy heat flux and anthropogenic heat discharge using aster image and meteorological data: case study in Beijing metropolitan area

Journal of Applied Remote Sensing, 2012

ABSTRACT In order to analyze the mechanism of the urban heat island, it is paramount and meaningf... more ABSTRACT In order to analyze the mechanism of the urban heat island, it is paramount and meaningful to estimate the anthropogenic heat flux in cities. A case study was carried out to study the energy balance process in Beijing, China, based on a canopy energy balance equation and to estimate the urban energy fluxes and anthropogenic heat discharge and their seasonal and spatial variations. Two ASTER images and meteorological observation data from the winter and summer seasons were used for the study. The results showed that: (1) in Beijing, the anthropogenic heat discharge flux reached a maximum of 163.76 W m-2 in winter and 288.26 W m-2 in summer. Spatially, the magnitude of the flux was significantly affected by urban land cover types. In winter, the highest value occurred at an urban commercial district with an average value of 47.60 W m-2. In summer, the highest value occurred at the airport and the industrial areas with the regional average reaching 47.29 W m-2 the spatial pattern of the heat discharge appears to be clustered, with some, localized high-accumulation centers such as in industrial areas and commercial districts. (2) The anthropogenic discharge was one of the important contributors to the surface-atmosphere energy exchange in cities. The heat discharge had a positive effect on elevating the surface temperature and formation of the urban heat island, especially in the summer. The study confirms the importance to account for the impact of the anthropogenic heat flux on urban energy budget.

Research paper thumbnail of A surface acoustic wave humidity sensor based on electrosprayed silicon-containing polyelectrolyte

Sensors and Actuators B: Chemical, 2010