Lingmei Jiang - Academia.edu (original) (raw)

Papers by Lingmei Jiang

2012 IEEE International Geoscience and Remote Sensing Symposium, 2012

ABSTRACT It is very crucial for developing satellite land data assimilation system by directly as... more ABSTRACT It is very crucial for developing satellite land data assimilation system by directly assimilating the gridded satellite brightness temperature (TB) data to simulate gridded satellite observation data. A dual-phase satellite data simulation system framework is developed, which consists of the Community Land Model (CLM), microwave Land Emissivity Model (LandEM), Shuffled Complex Evolution algorithm (SCE-UA) and the gridded Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) TB data, and it is implemented in two phases: the parameter optimization and calibration phase and the satellite data simulation phase. The SCE-UA algorithm is used to optimize the LandEM parameters and calibrate microwave wetland surface emissivity by minimizing the difference between the simulated and observed BT. In this paper, the monthly mean microwave wetland surface emissivity calibrated at HeFei in 2003 are transferred to East Asia region, the dual-phase satellite data simulation system is mainly evaluated over China region. Experimental results indicated that the vertically polarized TBs (6.925 GHz and 10.65 GHz) simulated by the dual-phase satellite data simulation system are basically matched with those observed by AMSR-E sensor and the differences between the simulated and observed TBs are less than 15 K, which indicates that the calibrated microwave wetland surface emissivity possesses excellent transportability and the dual-phase satellite data simulation system is feasible and practical over China. This study provides reference for developing China satellite land data assimilation system by directly assimilating the gridded AMSR-E TB data (low-frequency and vertical polarization) for model grids contained various land cover types, especially for those model grids including wetland cover type, which will greatly improve land data assimilation study.

Proceedings. 2005 IEEE International Geoscience and Remote Sensing Symposium, 2005. IGARSS '05., 2000

ABSTRACT This study describes a semi-empirical bare surface emission model for AMSR-E. Through ev... more ABSTRACT This study describes a semi-empirical bare surface emission model for AMSR-E. Through evaluation of a bare surface emission database generated by the Advanced Integral Equation Model (AIEM) for a wide range of surface dielectric and roughness properties under AMSR-E, we developed a new semi-empirical multi-frequency-polarization surface emission model - the Qp model. This model relates the effects of the surface roughness on the emission signals through the roughness variable Qp at different polarization - p (v or h). The Qp can be simply described as a single surface roughness property of the random surface slope - S. The comparison of the simulations by the Qp and AIEM models indicated that the error is extremely small, its magnitude is only as 10 -3 . The evaluation of this model with the field experimental data also showed a very good agreement. We will show its validation with the field ground radiometer measurement and its application in estimation of soil moisture.

We present details of the construction and characterization of the SDSS Southern Survey. This sur... more We present details of the construction and characterization of the SDSS Southern Survey. This survey consists of 300 sq-degrees of repeated scanning by the SDSS camera over -60 < RA < 60 on the equator. Each piece of sky has 20-30 images contributing and we will reach 2 magnitudes fainter than the SDSS single pass data. By using the repeated standard SDSS calibration, the apache wheel based ubercalibration, and the repeat scans themselves we obtain 1% photometry. We discuss the image coaddition techniques, the PSF construction, and the object measurement using frames of the SDSS PHOTO pipeline. Of interest is the fact that production occurred on the Open Science Grid using hundreds of compute nodes on >10 Terabytes of data. We present star counts, galaxy counts, the galaxy two-pt correlation function, and a photo-z distribution as the base characterization of the data set and we discuss the opportunities for using the dataset to extend the SDSS optical cluster catalog work out to redshifts of z > 0.5.

Igarss 2008 2008 Ieee International Geoscience and Remote Sensing Symposium, Jul 7, 2008

ERS wind scatterometer provides capability of the multiple angles by their three different look a... more ERS wind scatterometer provides capability of the multiple angles by their three different look antennas, In this study, we evaluate whether the multi-incidence angle observations can help on improving surface soil moisture estimations. With the theoretical surface backscattering model - the advanced integral equation Model (AIEM), we first simulated a surface backscattering database with a wide range of surface roughness

Journal of Materials Chemistry, 2010

RSC Publishing Logo View PDF VersionView Previous ArticleView Next Article DOI:10.1039/ C0JM00672... more RSC Publishing Logo View PDF VersionView Previous ArticleView Next Article DOI:10.1039/ C0JM00672F (Paper) J. Mater. Chem., 2010, 20, 5462-5467. Mono dispersed SnO 2 nanoparticles on both sides of single layer graphene sheets as anode materials in Li-ion batteries†. ...

2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS, 2013

ABSTRACT In this study, the dielectric constants of 12 types of soil with different organic matte... more ABSTRACT In this study, the dielectric constants of 12 types of soil with different organic matter content were measured using the coaxial probe method by network analyzer (0.5-40 GHz) at room temperature (approx. 23°C). The observed dielectric constant increases only slowly with soil volumetric water content up to a transition point. Beyond the transition point, it increases rapidly with volumetric water content. It was found that the value of the transition point was higher and the observed dielectric constant was lower at the same soil volumetric water content and frequency for soil with higher organic matter content. A simple semi-empirical model was proposed to describe the dielectric behavior of soil with organic matter. This model was developed based on the refractive mixing dielectric model (RMDM).

2012 20th International Conference on Geoinformatics, 2012

ABSTRACT The creation of “depressionless” DEMs is the essential work of hydrological analysis, wh... more ABSTRACT The creation of “depressionless” DEMs is the essential work of hydrological analysis, which is usually a time-consuming task, especially for huge terrain datasets. This paper proposes an improved and versatile parallel algorithm which consists of three steps. Firstly, a parallel conflict detection based on flow direction of the border of each partition is proposed to check out the depressions on the boundary. Secondly, the depressions detected are filled by a bigger DEM received from other processors. Based on the conflict detection, the parallel filling process is done at last. Finally, the efficiency and scalability of the algorithm are tested on the DEMs of different size.

Advanced Materials Research, Feb 6, 2012

The Earth's weather and climate is strongly influenced by the properties of the underlying su... more The Earth's weather and climate is strongly influenced by the properties of the underlying surface. Much of the solar energy that drives the atmosphere first interacts with the land or sea surface. Over land regions this interaction is modulated by surface characteristics such as albedo, aerodynamic roughness length, leaf area index (LAI), etc. As these characteristics change, either from anthropogenic or natural land-cover disturbances, the amount of energy reaching the atmosphere from the land surface, and thus weather and climate, is expected to change. The goal of this research project is to determine the sensitivity of weather and climate to historical land-cover changes in the eastern China. Regional Atmospheric Modeling System (RAMS) coupled with the Simple Biosphere (SiB) model, SiB-RAMS, was used to perform a series of one-year ensemble simulations over the eastern China with the current (USGS Olson classification, 1992) and potential (Ramankutty and Foley, 1999) vegeta...

In this study, the AMSR/E soil moisture data product was assimilated to a Regional Atmospheric Mo... more In this study, the AMSR/E soil moisture data product was assimilated to a Regional Atmospheric Modeling System (RAMS) using EnKF to see how the soil moisture influence the climate , surface sensible heat flux, latent heat flux and how the data assimilation improve the simulation in the Plateau Tibetan. We used two nest grids in the study, one is coarse grid with the 100km grid spacing, and the other is fine grid with the 25km grid spacing. The fine grid's domain is the Plateau Tibetan and the coarse grid covers the Plateau Tibetan and the area around Plateau Tibetan. So we can not only study how the data assimilation improve the simulation but also know how the assimilation domain influence the around area. In the first model integration, the model's `default' soil moisture was used as the initial value in the model simulation and it is updated as the model going on. The second experiment uses the AMSR/E product as the initial value instead of the `default' soil mois...

2010 Ieee International Geoscience and Remote Sensing Symposium, 2010

ABSTRACT To investigate relief effects on microwave radiation, it is essential to experiment, bas... more ABSTRACT To investigate relief effects on microwave radiation, it is essential to experiment, based on track-mounted microwave radiometer. There are four relief factors affecting microwave radiation features in this study we have researched, which are hill slopes, hill elevation, hill aspects, and hill shadows. To compare with relief effect simulation, we built relief landscape in the field experiment to validate microwave radiation of hill-scale topography bias resulted from some of relief factors. In the final analysis, through the relief experiment observed results we consider hill-scale topography dose have influence on microwave radiation, and it can not be ignored in the retrieval of surface parameters.

International Conference on Earth Observation Data Processing and Analysis (ICEODPA), 2008

ABSTRACT Global brightness temperature simulations were performed at 0.25 degree resolution both ... more ABSTRACT Global brightness temperature simulations were performed at 0.25 degree resolution both including the atmospheric effect and pixel heterogeneity in wide wave band. For surfaces such as snow, deserts, and vegetation, volumetric scattering was calculated using a two-stream radiative transfer approximation. The reflection and transmission at the surface-air interface and lower boundary were derived by modifying the Frenel equations and QP model to account for cross-polarization. Several models were utilized to compute the optical parameters for the medium. Global Land Data Assimilation Systems (GLDAS) provided time series of the main input variables. These simulations were compared with Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) measurements in January, April, July, and September 2003, including both the spectral and temporal variations. A sensitivity study was also carried out to access the relative contributes of the main parameters (particularly the roughness and soil moisture). Difference between simulated and measured TBs were analyzed, discriminating possible issues either linked to the radiative transfer model or due to land surface parameters .

2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS, 2013

ABSTRACT Overpopulation, the rapid development of industrialization and the acceleration of urban... more ABSTRACT Overpopulation, the rapid development of industrialization and the acceleration of urban expansion, all of these factors have changed the characteristics of underlying surface and atmospheric environment, especially in the urban area. The urban effect on regional climate changes in BTT regions was analyzed by the Regional Atmospheric Model System (RAMS). We simulate and analyze three days changes during the time from July 1st to 4th, 2003 in the BTT areas. The results show that simulation and observation is almost the same. Furthermore, the rapid urbanization makes temperature and sensible heat flux increase significantly, but latent heat flux decrease in BTT regions.

The availability of time series of water and land surface energy budgets over China area is essen... more The availability of time series of water and land surface energy budgets over China area is essential for understanding the environmental system and potential climate change in this area. However, consistent observations of the land surface state variables are routinely unavailable. In the absence of long-term observations of the components of the water and land surface energy budgets, modeling can provide consistent fields of land surface fluxes and states. We simulated the components of surface energy balance (SEB) equation using Land Information System (LIS) for time period of 2002.11-2003.12. Residual analyses of SEB indicate that the distribution of residuals show some spatial and temporal characteristics. The temporal characteristics of residual distribution suggest that LIS can simulate energy flux better in spring and summer than in other time. The spatial characteristics indicate that LIS can simulate energy flux better in places with relative low latitude or low altitude t...

IEEE Transactions on Geoscience and Remote Sensing, 2015

ABSTRACT The dielectric property of vegetation has a considerable effect on the characteristics o... more ABSTRACT The dielectric property of vegetation has a considerable effect on the characteristics of the microwave radiation of vegetation. In frozen environments, when the temperature is colder than normal, changes such as increased soluble sugar and decreased moisture content (MC) can occur in the vegetation. The dielectric property of vegetation, which is almost entirely controlled by its free and bound water content, will also change. To characterize the dielectric behavior of vegetation in frozen regions, a sensitive experiment was conducted on holly leaves with a high-performance coaxial probe over a frequency range from 0.5 to 40 GHz and a temperature range from 0 °C to −20 °C. Based on the measurements and the physical properties of the constituent substances of vegetation, a semiempirical dielectric model for holly leaves in low temperature environments was developed. In this model, a decrease in MC, which causes a reduction in the complex permittivity, was described as an increase in the ice content. The complex permittivity of bound water was measured using a saturated sucrose solution at −6.5 °C. The research will provide a reference for the dielectric property study of the vegetation in frozen environments.

Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and Technology of China

2014 IEEE Geoscience and Remote Sensing Symposium, 2014

2009 IEEE International Geoscience and Remote Sensing Symposium, 2009

In order to evaluate the accuracy of snow water equivalent (SWE) inversion algorithm for passive ... more In order to evaluate the accuracy of snow water equivalent (SWE) inversion algorithm for passive microwave sensor Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) in Western China, we compared SWE got from AMSR-E daily SWE product with the ground measurements from 15 meteorological stations in Tibetan plateau. The results show AMSR-E overestimate SWE in this regions and the RMSE is 21mm Tibetan plateau. Through incorporating snow fraction factor, a new empirical algorithm estimate snow depth and SWE have been developed in Tibet. This new algorithm appeared higher accuracy than AMSR-E. Due to complex topography, shallow patchy snow and frozen grounds covered at the Tibetan Plateau, this technique didn&amp;#x27;t show good results. In future we will focus on how to evaluate and eliminate the effects of these factors quantitatively on SWE retrieval.

2010 IEEE International Geoscience and Remote Sensing Symposium, 2010

Snow extent and snow depth (SD) are critical parameters in metro-hydrological models and are sens... more Snow extent and snow depth (SD) are critical parameters in metro-hydrological models and are sensitive to the global climate change. Over the western China, due to the influence from shallow snow, changing seasonal permafrost and the sparse observation stations, the passive microwave remote sensing algorithm show its applicability when using the gradient brightness temperature (Tb) algorithm of 36.5Ghz-18.7Ghz. In this work, we employ one whole-winter Tb extracted from Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) L2A swath dataset and the ground measurements of snow depth (SD) to analyse the snow microwave emission and gradient algorithm ability. The time series analysis shows that the Tb differences (36.5-18.7) and (36.5-10.7) are sensitive to relatively deep snow (&amp;gt;20cm), while the Tb differences (89.0-18.7) are sensitive to the occurrence of the new snow, with a promising correlation with shallow snow (&amp;lt;;15cm) and quickly decreasing (melting) snow depth, which suggest that a high frequency Tb difference could potentially be a good snow monitoring signal for the shallow snow cover over western China.

Physics and Chemistry of the Earth, Parts A/B/C, 2015

ABSTRACT Surface soil moisture is an important parameter in hydrology and climate investigations.... more ABSTRACT Surface soil moisture is an important parameter in hydrology and climate investigations. Current and future satellite missions with L-band passive microwave radiometers can provide valuable information for monitoring the global soil moisture. A factor that can play a significant role in the modeling and inversion of microwave emission from land surfaces is the surface roughness. In this study, an L-band parametric emission model for exponentially correlated surfaces was developed and implemented in a soil moisture retrieval algorithm. The approach was based on the parameterization of an effective roughness parameter of Hp in relation with the geometric roughness variables (root mean square height s and correlation length l) and incidence angle. The parameterization was developed based on a large set of simulations using an analytical approach incorporated in the advanced integral equation model (AIEM) over a wide range of geophysical properties. It was found that the effective roughness parameter decreases as surface roughness increases, but increases as incidence angle increases. In contrast to previous research, Hp was found to be expressed as a function of a defined slope parameter m = s2/l, and coefficients of the function could be well described by a quadratic equation. The parametric model was then tested with L-band satellite data in soil moisture retrieval algorithm over the Little Washita watershed, which resulted in an unbiased root mean square error of about 0.03 m3/m3 and 0.04 m3/m3 for ascending and descending orbits, respectively.

2012 IEEE International Geoscience and Remote Sensing Symposium, 2012

ABSTRACT It is very crucial for developing satellite land data assimilation system by directly as... more ABSTRACT It is very crucial for developing satellite land data assimilation system by directly assimilating the gridded satellite brightness temperature (TB) data to simulate gridded satellite observation data. A dual-phase satellite data simulation system framework is developed, which consists of the Community Land Model (CLM), microwave Land Emissivity Model (LandEM), Shuffled Complex Evolution algorithm (SCE-UA) and the gridded Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) TB data, and it is implemented in two phases: the parameter optimization and calibration phase and the satellite data simulation phase. The SCE-UA algorithm is used to optimize the LandEM parameters and calibrate microwave wetland surface emissivity by minimizing the difference between the simulated and observed BT. In this paper, the monthly mean microwave wetland surface emissivity calibrated at HeFei in 2003 are transferred to East Asia region, the dual-phase satellite data simulation system is mainly evaluated over China region. Experimental results indicated that the vertically polarized TBs (6.925 GHz and 10.65 GHz) simulated by the dual-phase satellite data simulation system are basically matched with those observed by AMSR-E sensor and the differences between the simulated and observed TBs are less than 15 K, which indicates that the calibrated microwave wetland surface emissivity possesses excellent transportability and the dual-phase satellite data simulation system is feasible and practical over China. This study provides reference for developing China satellite land data assimilation system by directly assimilating the gridded AMSR-E TB data (low-frequency and vertical polarization) for model grids contained various land cover types, especially for those model grids including wetland cover type, which will greatly improve land data assimilation study.

Proceedings. 2005 IEEE International Geoscience and Remote Sensing Symposium, 2005. IGARSS '05., 2000

ABSTRACT This study describes a semi-empirical bare surface emission model for AMSR-E. Through ev... more ABSTRACT This study describes a semi-empirical bare surface emission model for AMSR-E. Through evaluation of a bare surface emission database generated by the Advanced Integral Equation Model (AIEM) for a wide range of surface dielectric and roughness properties under AMSR-E, we developed a new semi-empirical multi-frequency-polarization surface emission model - the Qp model. This model relates the effects of the surface roughness on the emission signals through the roughness variable Qp at different polarization - p (v or h). The Qp can be simply described as a single surface roughness property of the random surface slope - S. The comparison of the simulations by the Qp and AIEM models indicated that the error is extremely small, its magnitude is only as 10 -3 . The evaluation of this model with the field experimental data also showed a very good agreement. We will show its validation with the field ground radiometer measurement and its application in estimation of soil moisture.

We present details of the construction and characterization of the SDSS Southern Survey. This sur... more We present details of the construction and characterization of the SDSS Southern Survey. This survey consists of 300 sq-degrees of repeated scanning by the SDSS camera over -60 < RA < 60 on the equator. Each piece of sky has 20-30 images contributing and we will reach 2 magnitudes fainter than the SDSS single pass data. By using the repeated standard SDSS calibration, the apache wheel based ubercalibration, and the repeat scans themselves we obtain 1% photometry. We discuss the image coaddition techniques, the PSF construction, and the object measurement using frames of the SDSS PHOTO pipeline. Of interest is the fact that production occurred on the Open Science Grid using hundreds of compute nodes on >10 Terabytes of data. We present star counts, galaxy counts, the galaxy two-pt correlation function, and a photo-z distribution as the base characterization of the data set and we discuss the opportunities for using the dataset to extend the SDSS optical cluster catalog work out to redshifts of z > 0.5.

Igarss 2008 2008 Ieee International Geoscience and Remote Sensing Symposium, Jul 7, 2008

ERS wind scatterometer provides capability of the multiple angles by their three different look a... more ERS wind scatterometer provides capability of the multiple angles by their three different look antennas, In this study, we evaluate whether the multi-incidence angle observations can help on improving surface soil moisture estimations. With the theoretical surface backscattering model - the advanced integral equation Model (AIEM), we first simulated a surface backscattering database with a wide range of surface roughness

Journal of Materials Chemistry, 2010

RSC Publishing Logo View PDF VersionView Previous ArticleView Next Article DOI:10.1039/ C0JM00672... more RSC Publishing Logo View PDF VersionView Previous ArticleView Next Article DOI:10.1039/ C0JM00672F (Paper) J. Mater. Chem., 2010, 20, 5462-5467. Mono dispersed SnO 2 nanoparticles on both sides of single layer graphene sheets as anode materials in Li-ion batteries†. ...

2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS, 2013

ABSTRACT In this study, the dielectric constants of 12 types of soil with different organic matte... more ABSTRACT In this study, the dielectric constants of 12 types of soil with different organic matter content were measured using the coaxial probe method by network analyzer (0.5-40 GHz) at room temperature (approx. 23°C). The observed dielectric constant increases only slowly with soil volumetric water content up to a transition point. Beyond the transition point, it increases rapidly with volumetric water content. It was found that the value of the transition point was higher and the observed dielectric constant was lower at the same soil volumetric water content and frequency for soil with higher organic matter content. A simple semi-empirical model was proposed to describe the dielectric behavior of soil with organic matter. This model was developed based on the refractive mixing dielectric model (RMDM).

2012 20th International Conference on Geoinformatics, 2012

ABSTRACT The creation of “depressionless” DEMs is the essential work of hydrological analysis, wh... more ABSTRACT The creation of “depressionless” DEMs is the essential work of hydrological analysis, which is usually a time-consuming task, especially for huge terrain datasets. This paper proposes an improved and versatile parallel algorithm which consists of three steps. Firstly, a parallel conflict detection based on flow direction of the border of each partition is proposed to check out the depressions on the boundary. Secondly, the depressions detected are filled by a bigger DEM received from other processors. Based on the conflict detection, the parallel filling process is done at last. Finally, the efficiency and scalability of the algorithm are tested on the DEMs of different size.

Advanced Materials Research, Feb 6, 2012

The Earth's weather and climate is strongly influenced by the properties of the underlying su... more The Earth's weather and climate is strongly influenced by the properties of the underlying surface. Much of the solar energy that drives the atmosphere first interacts with the land or sea surface. Over land regions this interaction is modulated by surface characteristics such as albedo, aerodynamic roughness length, leaf area index (LAI), etc. As these characteristics change, either from anthropogenic or natural land-cover disturbances, the amount of energy reaching the atmosphere from the land surface, and thus weather and climate, is expected to change. The goal of this research project is to determine the sensitivity of weather and climate to historical land-cover changes in the eastern China. Regional Atmospheric Modeling System (RAMS) coupled with the Simple Biosphere (SiB) model, SiB-RAMS, was used to perform a series of one-year ensemble simulations over the eastern China with the current (USGS Olson classification, 1992) and potential (Ramankutty and Foley, 1999) vegeta...

In this study, the AMSR/E soil moisture data product was assimilated to a Regional Atmospheric Mo... more In this study, the AMSR/E soil moisture data product was assimilated to a Regional Atmospheric Modeling System (RAMS) using EnKF to see how the soil moisture influence the climate , surface sensible heat flux, latent heat flux and how the data assimilation improve the simulation in the Plateau Tibetan. We used two nest grids in the study, one is coarse grid with the 100km grid spacing, and the other is fine grid with the 25km grid spacing. The fine grid's domain is the Plateau Tibetan and the coarse grid covers the Plateau Tibetan and the area around Plateau Tibetan. So we can not only study how the data assimilation improve the simulation but also know how the assimilation domain influence the around area. In the first model integration, the model's `default' soil moisture was used as the initial value in the model simulation and it is updated as the model going on. The second experiment uses the AMSR/E product as the initial value instead of the `default' soil mois...

2010 Ieee International Geoscience and Remote Sensing Symposium, 2010

ABSTRACT To investigate relief effects on microwave radiation, it is essential to experiment, bas... more ABSTRACT To investigate relief effects on microwave radiation, it is essential to experiment, based on track-mounted microwave radiometer. There are four relief factors affecting microwave radiation features in this study we have researched, which are hill slopes, hill elevation, hill aspects, and hill shadows. To compare with relief effect simulation, we built relief landscape in the field experiment to validate microwave radiation of hill-scale topography bias resulted from some of relief factors. In the final analysis, through the relief experiment observed results we consider hill-scale topography dose have influence on microwave radiation, and it can not be ignored in the retrieval of surface parameters.

International Conference on Earth Observation Data Processing and Analysis (ICEODPA), 2008

ABSTRACT Global brightness temperature simulations were performed at 0.25 degree resolution both ... more ABSTRACT Global brightness temperature simulations were performed at 0.25 degree resolution both including the atmospheric effect and pixel heterogeneity in wide wave band. For surfaces such as snow, deserts, and vegetation, volumetric scattering was calculated using a two-stream radiative transfer approximation. The reflection and transmission at the surface-air interface and lower boundary were derived by modifying the Frenel equations and QP model to account for cross-polarization. Several models were utilized to compute the optical parameters for the medium. Global Land Data Assimilation Systems (GLDAS) provided time series of the main input variables. These simulations were compared with Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) measurements in January, April, July, and September 2003, including both the spectral and temporal variations. A sensitivity study was also carried out to access the relative contributes of the main parameters (particularly the roughness and soil moisture). Difference between simulated and measured TBs were analyzed, discriminating possible issues either linked to the radiative transfer model or due to land surface parameters .

2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS, 2013

ABSTRACT Overpopulation, the rapid development of industrialization and the acceleration of urban... more ABSTRACT Overpopulation, the rapid development of industrialization and the acceleration of urban expansion, all of these factors have changed the characteristics of underlying surface and atmospheric environment, especially in the urban area. The urban effect on regional climate changes in BTT regions was analyzed by the Regional Atmospheric Model System (RAMS). We simulate and analyze three days changes during the time from July 1st to 4th, 2003 in the BTT areas. The results show that simulation and observation is almost the same. Furthermore, the rapid urbanization makes temperature and sensible heat flux increase significantly, but latent heat flux decrease in BTT regions.

The availability of time series of water and land surface energy budgets over China area is essen... more The availability of time series of water and land surface energy budgets over China area is essential for understanding the environmental system and potential climate change in this area. However, consistent observations of the land surface state variables are routinely unavailable. In the absence of long-term observations of the components of the water and land surface energy budgets, modeling can provide consistent fields of land surface fluxes and states. We simulated the components of surface energy balance (SEB) equation using Land Information System (LIS) for time period of 2002.11-2003.12. Residual analyses of SEB indicate that the distribution of residuals show some spatial and temporal characteristics. The temporal characteristics of residual distribution suggest that LIS can simulate energy flux better in spring and summer than in other time. The spatial characteristics indicate that LIS can simulate energy flux better in places with relative low latitude or low altitude t...

IEEE Transactions on Geoscience and Remote Sensing, 2015

ABSTRACT The dielectric property of vegetation has a considerable effect on the characteristics o... more ABSTRACT The dielectric property of vegetation has a considerable effect on the characteristics of the microwave radiation of vegetation. In frozen environments, when the temperature is colder than normal, changes such as increased soluble sugar and decreased moisture content (MC) can occur in the vegetation. The dielectric property of vegetation, which is almost entirely controlled by its free and bound water content, will also change. To characterize the dielectric behavior of vegetation in frozen regions, a sensitive experiment was conducted on holly leaves with a high-performance coaxial probe over a frequency range from 0.5 to 40 GHz and a temperature range from 0 °C to −20 °C. Based on the measurements and the physical properties of the constituent substances of vegetation, a semiempirical dielectric model for holly leaves in low temperature environments was developed. In this model, a decrease in MC, which causes a reduction in the complex permittivity, was described as an increase in the ice content. The complex permittivity of bound water was measured using a saturated sucrose solution at −6.5 °C. The research will provide a reference for the dielectric property study of the vegetation in frozen environments.

Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and Technology of China

2014 IEEE Geoscience and Remote Sensing Symposium, 2014

2009 IEEE International Geoscience and Remote Sensing Symposium, 2009

In order to evaluate the accuracy of snow water equivalent (SWE) inversion algorithm for passive ... more In order to evaluate the accuracy of snow water equivalent (SWE) inversion algorithm for passive microwave sensor Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) in Western China, we compared SWE got from AMSR-E daily SWE product with the ground measurements from 15 meteorological stations in Tibetan plateau. The results show AMSR-E overestimate SWE in this regions and the RMSE is 21mm Tibetan plateau. Through incorporating snow fraction factor, a new empirical algorithm estimate snow depth and SWE have been developed in Tibet. This new algorithm appeared higher accuracy than AMSR-E. Due to complex topography, shallow patchy snow and frozen grounds covered at the Tibetan Plateau, this technique didn&amp;#x27;t show good results. In future we will focus on how to evaluate and eliminate the effects of these factors quantitatively on SWE retrieval.

2010 IEEE International Geoscience and Remote Sensing Symposium, 2010

Snow extent and snow depth (SD) are critical parameters in metro-hydrological models and are sens... more Snow extent and snow depth (SD) are critical parameters in metro-hydrological models and are sensitive to the global climate change. Over the western China, due to the influence from shallow snow, changing seasonal permafrost and the sparse observation stations, the passive microwave remote sensing algorithm show its applicability when using the gradient brightness temperature (Tb) algorithm of 36.5Ghz-18.7Ghz. In this work, we employ one whole-winter Tb extracted from Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) L2A swath dataset and the ground measurements of snow depth (SD) to analyse the snow microwave emission and gradient algorithm ability. The time series analysis shows that the Tb differences (36.5-18.7) and (36.5-10.7) are sensitive to relatively deep snow (&amp;gt;20cm), while the Tb differences (89.0-18.7) are sensitive to the occurrence of the new snow, with a promising correlation with shallow snow (&amp;lt;;15cm) and quickly decreasing (melting) snow depth, which suggest that a high frequency Tb difference could potentially be a good snow monitoring signal for the shallow snow cover over western China.

Physics and Chemistry of the Earth, Parts A/B/C, 2015

ABSTRACT Surface soil moisture is an important parameter in hydrology and climate investigations.... more ABSTRACT Surface soil moisture is an important parameter in hydrology and climate investigations. Current and future satellite missions with L-band passive microwave radiometers can provide valuable information for monitoring the global soil moisture. A factor that can play a significant role in the modeling and inversion of microwave emission from land surfaces is the surface roughness. In this study, an L-band parametric emission model for exponentially correlated surfaces was developed and implemented in a soil moisture retrieval algorithm. The approach was based on the parameterization of an effective roughness parameter of Hp in relation with the geometric roughness variables (root mean square height s and correlation length l) and incidence angle. The parameterization was developed based on a large set of simulations using an analytical approach incorporated in the advanced integral equation model (AIEM) over a wide range of geophysical properties. It was found that the effective roughness parameter decreases as surface roughness increases, but increases as incidence angle increases. In contrast to previous research, Hp was found to be expressed as a function of a defined slope parameter m = s2/l, and coefficients of the function could be well described by a quadratic equation. The parametric model was then tested with L-band satellite data in soil moisture retrieval algorithm over the Little Washita watershed, which resulted in an unbiased root mean square error of about 0.03 m3/m3 and 0.04 m3/m3 for ascending and descending orbits, respectively.