期刊文献+
共找到51篇文章
< 1 2 3 >
每页显示 20 50 100
Advances in Research on Soil Moisture by Microwave Remote Sensing in China 被引量:9
1
作者 SONG Dongsheng ZHAO Kai GUAN Zhi 《Chinese Geographical Science》 SCIE CSCD 2007年第2期186-191,共6页
Soil moisture is an important factor in global hydrologic circulation and plays a significant role in the research of hydrology, climatology, and agriculture. Microwave remote sensing is less limited by climate and ti... Soil moisture is an important factor in global hydrologic circulation and plays a significant role in the research of hydrology, climatology, and agriculture. Microwave remote sensing is less limited by climate and time, and can measure in large scale. With these characteristics, this technique becomes an effective tool to measure soil moisture. Since the 1980s, Chinese researchers have investigated the soil moisture using microwave instruments. The active re- mote sensors are characteristic of high spatial resolution, thus with launch of a series of satellites, active microwave remote sensing of soil moisture will be emphasized. The passive microwave remote sensing of soil moisture has a long research history, and its retrieval algorithms were developed well, so it is an important tool to retrieve large scale moisture information from satellite data in the future. 展开更多
关键词 microwave remote sensing soil moisture active microwave remote sensing passive microwave remote sensing
下载PDF
Comparisons of passive microwave remote sensing sea ice concentrations with ship-based visual observations during the CHINARE Arctic summer cruises of 2010–2018 被引量:6
2
作者 Yuanren Xiu Zhijun Li +3 位作者 Ruibo Lei Qingkai Wang Peng Lu Matti Leppäranta 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2020年第9期38-49,共12页
In order to apply satellite data to guiding navigation in the Arctic more effectively,the sea ice concentrations(SIC)derived from passive microwave(PM)products were compared with ship-based visual observations(OBS)col... In order to apply satellite data to guiding navigation in the Arctic more effectively,the sea ice concentrations(SIC)derived from passive microwave(PM)products were compared with ship-based visual observations(OBS)collected during the Chinese National Arctic Research Expeditions(CHINARE).A total of 3667 observations were collected in the Arctic summers of 2010,2012,2014,2016,and 2018.PM SIC were derived from the NASA-Team(NT),Bootstrap(BT)and Climate Data Record(CDR)algorithms based on the SSMIS sensor,as well as the BT,enhanced NASA-Team(NT2)and ARTIST Sea Ice(ASI)algorithms based on AMSR-E/AMSR-2 sensors.The daily arithmetic average of PM SIC values and the daily weighted average of OBS SIC values were used for the comparisons.The correlation coefficients(CC),biases and root mean square deviations(RMSD)between PM SIC and OBS SIC were compared in terms of the overall trend,and under mild/normal/severe ice conditions.Using the OBS data,the influences of floe size and ice thickness on the SIC retrieval of different PM products were evaluated by calculating the daily weighted average of floe size code and ice thickness.Our results show that CC values range from 0.89(AMSR-E/AMSR-2 NT2)to 0.95(SSMIS NT),biases range from−3.96%(SSMIS NT)to 12.05%(AMSR-E/AMSR-2 NT2),and RMSD values range from 10.81%(SSMIS NT)to 20.15%(AMSR-E/AMSR-2 NT2).Floe size has a significant influence on the SIC retrievals of the PM products,and most of the PM products tend to underestimate SIC under smaller floe size conditions and overestimate SIC under larger floe size conditions.Ice thickness thicker than 30 cm does not have a significant influence on the SIC retrieval of PM products.Overall,the best(worst)agreement occurs between OBS SIC and SSMIS NT(AMSR-E/AMSR-2 NT2)SIC in the Arctic summer. 展开更多
关键词 sea ice concentration passive microwave remote sensing ship-based visual observations Arctic navigation SUMMER
下载PDF
A Method for Surface Roughness Parameter Estimation in Passive Microwave Remote Sensing 被引量:4
3
作者 ZHENG Xingming ZHAO Kai 《Chinese Geographical Science》 SCIE CSCD 2010年第4期345-352,共8页
Surface roughness parameter is an important factor and obstacle for retrieving soil moisture in passive microwave remote sensing.Two statistical parameters,root mean square (RMS) height (s) and correlation length (l),... Surface roughness parameter is an important factor and obstacle for retrieving soil moisture in passive microwave remote sensing.Two statistical parameters,root mean square (RMS) height (s) and correlation length (l),are designed for describing the roughness of a randomly rough surface.The roughness parameter measured by traditional way is independence of frequency,soil moisture and soil heterogeneity and just the ″geometric″ roughness of random surface.This ″geometric″ roughness can not fully explain the scattered thermal radiation by the earth's surface.The relationship between ″geometric″ roughness and integrated roughness (contain both ″geometric″ roughness and ″dielectric″ roughness) is linked by empirical coefficient.In view of this problem,this paper presents a method for estimating integrated surface roughness from radiometer sampling data at different frequencies,which mainly based on the flourier relationship between power spectral density distribution and spatial autocorrelation function.We can obtain integrated surface roughness at different frequencies by this method.Besides "geometric" roughness,this integrated surface roughness not only contains "dielectric" roughness but also includes frequency dependence.Combined with Q/H model the polarization coupling coefficient can also be obtained for both H and V polarization.Meanwhile,the simulated numerical results show that radiometer with a sensitivity of 0.1 K can distinguish the different surface roughness and the change of roughness with frequency for the same rough surface.This confirms the feasibility of radiometer sampling method for estimating the surface roughness theoretically.This method overcomes the problem of ″dielectric″ roughness measurement to some extent and can achieve the integrated surface roughness within a microwave pixel which can serve soil moisture inversion better than the ″geometric″ roughness. 展开更多
关键词 surface roughness passive microwave remote sensing statistical parameter estimation soil moisture RADIOMETER
下载PDF
STUDY AND APPLICATION OF THE AERIAL PASSIVE MICROWAVE REMOTE SENSING 被引量:2
4
作者 Zhao Renyu, Zhang Junrong, Guo Fenglian, Zhao Kai, Hu Xuewei, Liu Baojiang (Changchun Institute of Geography, Academia Sinica) 《遥感信息》 CSCD 1990年第A02期34-36,共3页
Ⅰ. Introduction Over the past two decades, microwave remote sensing has evolved into a focal point in the remote sensing area. This is due to the fact that in microwave band, we can acquire physical parameters about ... Ⅰ. Introduction Over the past two decades, microwave remote sensing has evolved into a focal point in the remote sensing area. This is due to the fact that in microwave band, we can acquire physical parameters about ocean, terrain and atmosphere on all weather condition. Research and application work about the aerial passive micro wave remote sensors has been done at Changchun Institute of Geography since 1973, under the unitary planning of Academia Sinica. Microwave radiometers of six freqency bands have been developed. Numerous remote sensing experiments were carried out, and large amount of scientific data were accumulated. Recently, theoretical models have 展开更多
关键词 STUDY AND APPLICATION OF THE AERIAL PASSIVE microwave remote sensing BAY
下载PDF
Study on Microwave Remote Sensing of Atmosphere,Cloud and Rain
5
作者 赵柏林 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1990年第4期475-490,共16页
In this paper, recent research of microwave remote sensing of atmosphere, cloud and rain in China is presented. It includes the following aspects:(1) Progress in the development of multifrequency radiometer and its ch... In this paper, recent research of microwave remote sensing of atmosphere, cloud and rain in China is presented. It includes the following aspects:(1) Progress in the development of multifrequency radiometer and its characteristics and parameters;(2) Application of microwave remote sensing in prediction of atmospheric boundary layer. The atmospheric temperature profiles are derived with 5 mm (54.5 GHz) radiometer angle-scanning observations. Due to the fact that microwave radiometer could monitor the atmospheric temperature profile continuously and make the initialization of numerical model any time, it is helpful for improving the accuracy in prediction of the evolution of atmospheric boundary layer;(3) Theory and application of microwave radiometers in monitoring atmospheric temperature, humidity and water content in cloud. The field experiment of International Satellite Cloud Climatology Project (ISCCP) at Shionomisaki and Amami Oshima of Japan for studies of cloud and weather has been described;(4) Satellite remote sensing of atmosphere and colud. The TIROS-N TOYS satellite data are used to obtain atmospheric temperature profile. The results are compared with those of radiosonde, with rms deviation smaller than that of the current operational TOVS processing;(5) Microwave remote sensing and communication. The atmospheric attenuations are derived with microwave remote sensing methods such as solar radiation method etc., in order to obtain the local value instantaneously. The characteristics of Beijing's rainfall have been analysed and the probability of microwave attenuation of rain is predicted;(6) For improvement of the accuracy of rainfall measurement, a radiometer-radar system (λ= 3.2 cm) has been developed The variation of rainfall distribution and area-rainfall may be obtained by its measurements, which mav be helpful for hydrological prediction.The prospect of microwave remote sensing in meteorology is also discussed. 展开更多
关键词 Study on microwave remote sensing of Atmosphere Cloud and Rain
下载PDF
NUMERICAL MODELING OF RADIATIVE TRANSFER FOR MICROWAVE REMOTE SENSING
6
作者 Jin Yaqiu, Zhang Jurong, Zhao Renyu (Department of Electronic Engineering, Fudan University) (Changchun Institute of Geography, Academia Sinica) 《遥感信息》 CSCD 1990年第A02期30-31,共2页
An overall vector radiative transfer theory was developed for numerical modeling, in both active and passive microwave remote sensing. The Theory and approaches are briefly summerized.To quantitatively understand scat... An overall vector radiative transfer theory was developed for numerical modeling, in both active and passive microwave remote sensing. The Theory and approaches are briefly summerized.To quantitatively understand scattering and thermal emission from targets in active and passive remote sensing, we have developed an overall vector radiative transfer theory for a set of theoretical models of discrete scatterer and continuous random media for the earth terrain (wet soil, vegetation, snow, sea-ice, etc.) and atmosphere, and numerical approaches for simulation, data analysis, and parameter sensitivity test. Our numerical results favorably agreed with experimental data in microwave re mote sensing of various earth surfaces. Main approaches are briefly summerized herewith. 展开更多
关键词 VRT NUMERICAL MODELING OF RADIATIVE TRANSFER FOR microwave remote sensing
下载PDF
Progresses on microwave remote sensing of land surface parameters 被引量:25
7
作者 SHI JianCheng DU Yang +15 位作者 DU JinYang JIANG LingMei CHAI LinNa MAO KeBiao XU Peng NI WenJian XIONG Chuan LIU Qiang LIU ChenZhou GUO Peng CUI Qian LI YunQing CHEN Jing WANG AnQi LUO HeJia WANG YinHui 《Science China Earth Sciences》 SCIE EI CAS 2012年第7期1052-1078,共27页
Highly accurate observations at various scales on the land surface are urgently needed for the studies of many areas,such as hydrology,meteorology,and agriculture.With the rapid development of remote sensing technique... Highly accurate observations at various scales on the land surface are urgently needed for the studies of many areas,such as hydrology,meteorology,and agriculture.With the rapid development of remote sensing techniques,remote sensing has had the capacity of monitoring many factors of the Earth's land surface.Especially,the space-borne microwave remote sensing systems have been widely used in the quantitative monitoring of global snow,soil moisture,and vegetation parameters with their all-weather,all-time observation capabilities and their sensitivities to the characteristics of land surface factors.Based on the electromagnetic theories and microwave radiative transfer equations,researchers have achieved great successes in the microwave remote sensing studies for different sensors in recent years.This article has systematically reviewed the progresses on five research areas including microwave theoretical modeling,microwave inversion on soil moisture,snow,vegetation and land surface temperatures.Through the further enrichment of remote sensing datasets and the development of remote sensing theories and inversion techniques,remote sensing including microwave remote sensing will play a more important role in the studies and applications of the Earth systems. 展开更多
关键词 microwave remote sensing soil moisture VEGETATION snow water equivalent land surface temperature
原文传递
Review of snow water equivalent microwave remote sensing 被引量:8
8
作者 SHI JianCheng XIONG Chuan JIANG LingMei 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第4期731-745,共15页
Accurate quantitative global scale snow water equivalent information is crucial for meteorology, hydrology, water cycle and global change studies, and is of great importance for snow melt-runoff forecast, water resour... Accurate quantitative global scale snow water equivalent information is crucial for meteorology, hydrology, water cycle and global change studies, and is of great importance for snow melt-runoff forecast, water resources management and flood control. With land surface process model and snow process model, the snow water equivalent can be simulated with certain accuracy, with the forcing data as input. However, the snow water equivalent simulated using the snow process models has large uncertainties spatially and temporally, and it may be far from the needs of practical applications. Thus, the large scale snow water equivalent information is mainly from remote sensing. Beginning with the launch of Nimbus-7 satellite, the research on microwave snow water equivalent remote sensing has developed for more than 30 years, researchers have made progress in many aspects, including the electromagnetic scattering and emission modeling, ground and airborne experiments, and inversion algorithms for future global high resolution snow water equivalent remote sensing program. In this paper, the research and progress in the aspects of electromagnetic scattering/emission modeling over snow covered terrain and snow water equivalent inversion algorithm will be summarized. 展开更多
关键词 SNOW microwave remote sensing MODEL INVERSION
原文传递
Effects of spatial distribution of soil parameters on soil moisture retrieval from passive microwave remote sensing 被引量:5
9
作者 ZHANG Tao ZHANG LiXin +3 位作者 JIANG LingMei ZHAO ShaoJie ZHAO TianJie LI YunQing 《Science China Earth Sciences》 SCIE EI CAS 2012年第8期1313-1322,共10页
In this paper,we studied the effect of spatial distribution of soil parameters on passive soil moisture retrieval at pixel scale.First,we evaluated the forward microwave emission model and soil moisture retrieval algo... In this paper,we studied the effect of spatial distribution of soil parameters on passive soil moisture retrieval at pixel scale.First,we evaluated the forward microwave emission model and soil moisture retrieval algorithm accuracy through the observa-tion of field experiments.Then,we used soil parameters in different spatial distribution patterns,including random,normal,and uniform distribution,to determine the different levels of heterogeneity on soil moisture retrieval,in order to seek the rela-tionship between heterogeneity and soil moisture retrieval error.Finally,we conducted a controlled heterogeneity effect ex-periment measurements using a Truck-mounted Multi-frequency Radiometer(TMMR) to validate our simulation results.This work has proved that the soil moisture retrieval algorithm had a high accuracy(RMSE=0.049 cm3 cm 3) and can satisfy the need of this research.The simulation brightness temperatures match well with observations,with RMSE=9.89 K.At passive microwave remote sensing pixel scale,soil parameters with different spatial distribution patterns could have different levels of error on soil moisture estimation.Overall,we found that soil moisture with a random distribution in a satellite pixel scale can cause the largest error,with a normal distribution being the second,and a uniform distribution the least due to the smallest het-erogeneity. 展开更多
关键词 bare soil HETEROGENEITY spatial distribution passive microwave remote sensing soil moisture
原文传递
A lake ice phenology dataset for the Northern Hemisphere based on passive microwave remote sensing 被引量:4
10
作者 Xingxing Wang Yubao Qiu +4 位作者 Yixiao Zhang Juha Lemmetyinen Bin Cheng Wenshan Liang Matti Leppäranta 《Big Earth Data》 EI 2022年第4期401-419,共19页
Lake ice phenology(LIP)is an essential indicator of climate change and helps with understanding of the regional characteristics of climate change impacts.Ground observation records and remote sensing retrieval product... Lake ice phenology(LIP)is an essential indicator of climate change and helps with understanding of the regional characteristics of climate change impacts.Ground observation records and remote sensing retrieval products of lake ice phenology are abundant for Europe,North America,and the Tibetan Plateau,but there is a lack of data for inner Eurasia.In this work,enhanced-resolution passive microwave satellite data(PMW)were used to investigate the Northern Hemisphere Lake Ice Phenology(PMW LIP).The Freeze Onset(FO),Complete Ice Cover(CIC),Melt Onset(MO),and Complete Ice Free(CIF)dates were derived for 753 lakes,including 409 lakes for which ice phenology retrievals were available for the period 1978 to 2020 and 344 lakes for which these were available for 2002 to 2020.Verification of the PMW LIP using ground records gave correlation coefficients of 0.93 and 0.84 for CIC and CIF,respectively,and the corresponding values of the RMSE were 11.84 and 10.07 days.The lake ice phenology in this dataset was significantly correlated(P<0.001)with that obtained from Moderate Resolution Imaging Spectroradiometer(MODIS)data-the average correlation coefficient was 0.90 and the average RMSE was 7.87 days.The minimum RMSE was 4.39 days for CIF.The PMW is not affected by the weather or the amount of sunlight and thus provides more reliable data about the freezing and thawing process information than MODIS observations.The PMW LIP dataset pro-vides the basic freeze-thaw data that is required for research into lake ice and the impact of climate change in the cold regions of the Northern Hemisphere.The dataset is available at http://www.doi.org/10.11922/sciencedb.j00076.00081. 展开更多
关键词 Lake ice phenology dataset Northern Hemisphere passive microwave remote sensing
原文传递
LABORATORY STUDY ON MICROWAVE REMOTE SENSING OF GROUND TRUTH 被引量:1
11
作者 赵柏林 赵文中 韩庆源 《Acta meteorologica Sinica》 SCIE 1991年第3期317-330,共14页
In order to improve the interpretation of the earth system microwave remote sensing, the research of microwave spectrum characteristics of the ground truth (earth objects) was carried out in laboratory. A laboratory f... In order to improve the interpretation of the earth system microwave remote sensing, the research of microwave spectrum characteristics of the ground truth (earth objects) was carried out in laboratory. A laboratory for microwave remote sensing of the earth objects has been constructed to improve the remote sensing level, the laboratory consists of four parts: the measuring system of dielectric constants, the microwave emissivity meter, the microwave reflectometer and the microwave remote sensing simulation experiment in field. In this paper, the principle of measurement, the correction of near field process, the structure of instrument, the calibration method and the measurement of the earth substances, including soil, water and oil, are discussed. The labora- tory may supply the condition for measuring the parameters of thc earth substance remote sensing and help to interpret the remote sensing data. 展开更多
关键词 microwave remote sensing ground truth microwave reflectivity microwave emissivity microwave dielectric constant
原文传递
SATELLITE MICROWAVE REMOTE SENSING OF FLOODING
12
作者 姚展予 李万彪 +3 位作者 高慧琳 朱元竞 赵柏林 张强 《Acta meteorologica Sinica》 SCIE 2004年第1期95-104,共10页
The ability of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) for flooding and soil wetness detection has been demonstrated in this study.On the basis of TMI measurements,four methods,the classi... The ability of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) for flooding and soil wetness detection has been demonstrated in this study.On the basis of TMI measurements,four methods,the classification method,the soil wetness index (SWI) method. the polarization difference index (PDI) method,and the polarization ratio index (PRI) method, were brought out to monitor flooding and study soil wetness in the Changjiang and Huaihe River Basins during the summer 1998.Compared with the images provided by L-band Synthetic Aperture Radar (L-SAR) and Radar Satellite (Radarsat) and the figures derived from daily rainfall data based on the Z-index method,the detection of flooding and soil wetness by TMI was proved to be feasible. 展开更多
关键词 TRMM/TMI (Tropical Rainfall Measuring Mission/TRMM microwave Imager) remote sensing FLOODING
原文传递
A study on remote sensing models of sea ice thickness by microwave radiometry
13
作者 Zheng Quan’an, Zhang Dong and Pan Jiayi The First Institute of Oceanography, State Oceanic Administration, P. O. Box 98, Qingdao 266003, China 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1993年第2期197-206,共10页
Extrapolating from the propagation theories of electromagnetic waves in a layered medium, a three-layer medium model is deduced in this paper by using microwave radiometric remote sensing technology which is suitable ... Extrapolating from the propagation theories of electromagnetic waves in a layered medium, a three-layer medium model is deduced in this paper by using microwave radiometric remote sensing technology which is suitable to first-year sea ice condition of the northern part of China seas. Comparison with in situ data indicates that for microwave wavelength of 10 cm, the coherent model gives a quite good fit result for the thickness of sea ice less than 20 cm, and the incoherent model also works well for thickness within 20 to 40 cm. Based on three theoretical models, the inversion soft ware from microwave remote sensing data for calculating the thickness of sea ice can be set up. The relative complex dielectrical constants of different types of sea ice in the Liaodong Gulf calculated by using these theoretical models and measurement data are given in this paper. The extent of their values is (0. 5-4. 0)-j(0. 07~0. 19). 展开更多
关键词 A study on remote sensing models of sea ice thickness by microwave radiometry
下载PDF
Insights into the Microwave Instruments Onboard the Fengyun 3D Satellite:Data Quality and Assimilation in the Met Office NWP System 被引量:4
14
作者 Fabien CARMINATI Nigel ATKINSON +1 位作者 Brett CANDY Qifeng LU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2021年第8期1379-1396,共18页
This paper evaluates the microwave instruments onboard the latest Chinese polar-orbiting satellite, Fengyun 3D (FY- 3D). Comparing three months of observations from the Microwave Temperature Sounder 2 (MWTS-2), the Mi... This paper evaluates the microwave instruments onboard the latest Chinese polar-orbiting satellite, Fengyun 3D (FY- 3D). Comparing three months of observations from the Microwave Temperature Sounder 2 (MWTS-2), the Microwave Humidity Sounder 2 (MWHS-2), and the Microwave Radiation Imager (MWRI) to Met Office short-range forecasts, we characterize the instrumental biases, show how those biases have changed with respect to their predecessors onboard FY- 3C, and how they compare to the Advanced Technology Microwave Sounder (ATMS) onboard NOAA-20 and the Global Precipitation Measurement Microwave Imager (GMI). The MWTS-2 global bias is much reduced with respect to its predecessor and compares well to ATMS at equivalent channel frequencies, differing only by 0.36 ± 0.28 K (1σ) on average. A suboptimal averaging of raw digital counts is found to cause an increase in striping noise and an ascending- descending bias. MWHS-2 benefits from a new calibration method improving the 183-GHz humidity channels with respect to its predecessor and biases for these channels are within ± 1.9 K to ATMS. MWRI presents the largest improvements, with reduced global bias and standard deviation with respect to FY-3C;although, spurious, seemingly transient, brightness temperatures have been detected in the observations at 36.5 GHz (vertical polarization). The strong solar-dependent bias that affects the instrument on FY-3C has been reduced to less than 0.2 K on average for FY-3D MWRI. Experiments where radiances from these instruments were assimilated on top of a full global system demonstrated a neutral to positive impact on the forecasts, as well as on the fit to the background of independent instruments. 展开更多
关键词 microwave remote sensing numerical weather prediction data assimilation
下载PDF
Improved Microwave Ocean Emissivity and Reflectivity Models Derived from Two-Scale Roughness Theory 被引量:2
15
作者 Lingli HE Fuzhong WENG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2023年第10期1923-1938,共16页
The Geometrical Optics(GO)approach and the FAST Emissivity Model(FASTEM)are widely used to estimate the surface radiative components in atmospheric radiative transfer simulations,but their applications are limited in ... The Geometrical Optics(GO)approach and the FAST Emissivity Model(FASTEM)are widely used to estimate the surface radiative components in atmospheric radiative transfer simulations,but their applications are limited in specific conditions.In this study,a two-scale reflectivity model(TSRM)and a two-scale emissivity model(TSEM)are developed from the two-scale roughness theory.Unlike GO which only computes six non-zero elements in the reflectivity matrix,The TSRM includes 16 elements of Stokes reflectivity matrix which are important for improving radiative transfer simulation accuracy in a scattering atmosphere.It covers the frequency range from L-to W-bands.The dependences of all TSRM elements on zenith angle,wind speed,and frequency are derived and analyzed in details.For a set of downwelling radiances in microwave frequencies,the reflected upwelling brightness temperature(BTs)are calculated from both TSRM and GO and compared for analyzing their discrepancies.The TSRM not only includes the effects of GO but also accounts for the small-scale Bragg scattering effect in an order of several degrees in Kelvins in brightness temperature.Also,the third and fourth components of the Stokes vector can only be produced from the TSRM.For the emitted radiation,BT differences in vertical polarization between a TSEM and FASTEM are generally less than 5 K when the satellite zenith angle is less than 40°,whereas those for the horizontal component can be quite significant,greater than 20 K. 展开更多
关键词 EMISSIVITY microwave remote sensing reflectivity matrix two-scale roughness theory
下载PDF
Coupling numerical simulation with remotely sensed information for the study of frozen soil dynamics 被引量:2
16
作者 HuiRan Gao WanChang Zhang 《Research in Cold and Arid Regions》 CSCD 2020年第6期404-417,共14页
The acquisition of spatial-temporal information of frozen soil is fundamental for the study of frozen soil dynamics and its feedback to climate change in cold regions.With advancement of remote sensing and better unde... The acquisition of spatial-temporal information of frozen soil is fundamental for the study of frozen soil dynamics and its feedback to climate change in cold regions.With advancement of remote sensing and better understanding of frozen soil dynamics,discrimination of freeze and thaw status of surface soil based on passive microwave remote sensing and numerical simulation of frozen soil processes under water and heat transfer principles provides valuable means for regional and global frozen soil dynamic monitoring and systematic spatial-temporal responses to global change.However,as an important data source of frozen soil processes,remotely sensed information has not yet been fully utilized in the numerical simulation of frozen soil processes.Although great progress has been made in remote sensing and frozen soil physics,yet few frozen soil research has been done on the application of remotely sensed information in association with the numerical model for frozen soil process studies.In the present study,a distributed numerical model for frozen soil dynamic studies based on coupled water-heat transferring theory in association with remotely sensed frozen soil datasets was developed.In order to reduce the uncertainty of the simulation,the remotely sensed frozen soil information was used to monitor and modify relevant parameters in the process of model simulation.The remotely sensed information and numerically simulated spatial-temporal frozen soil processes were validated by in-situ field observations in cold regions near the town of Naqu on the East-Central Tibetan Plateau.The results suggest that the overall accuracy of the algorithm for discriminating freeze and thaw status of surface soil based on passive microwave remote sensing was more than 95%.These results provided an accurate initial freeze and thaw status of surface soil for coupling and calibrating the numerical model of this study.The numerically simulated frozen soil processes demonstrated good performance of the distributed numerical model based on the coupled water-heat transferring theory.The relatively larger uncertainties of the numerical model were found in alternating periods between freezing and thawing of surface soil.The average accuracy increased by about 5%after integrating remotely sensed information on the surface soil.The simulation accuracy was significantly improved,especially in transition periods between freezing and thawing of the surface soil. 展开更多
关键词 frozen soil water-heat coupled model passive microwave remote sensing COUPLING frozen soil dynamics
下载PDF
Preliminary Study on Direct Assimilation of Cloud-affected Satellite Microwave Brightness Temperatures 被引量:1
17
作者 Sibo ZHANG Li GUAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第2期199-208,共10页
Direct assimilation of cloud-affected microwave brightness temperatures from AMSU-A into the GSI three-dimensional variational (3D-Var) assimilation system is preliminarily studied in this paper. A combination of cl... Direct assimilation of cloud-affected microwave brightness temperatures from AMSU-A into the GSI three-dimensional variational (3D-Var) assimilation system is preliminarily studied in this paper. A combination of cloud microphysics param- eters retrieved by the 1D-Var algorithm (including vertical profiles of cloud liquid water content, ice water content, and rain water content) and atmospheric state parameters from objective analysis fields of an NWP model are used as background fields. Three cloud microphysics parameters (cloud liquid water content, ice water content, and rain water content) are ap- plied to the control variable. Typhoon Halong (2014) is selected as an example. The results show that direct assimilation of cloud-affected AMSU-A observations can effectively adjust the structure of large-scale temperature, humidity and wind anal- ysis fields due to the assimilation of more AMSU-A observations in typhoon cloudy areas, especially typhoon spiral cloud belts. These adjustments, with temperatures increasing and humidities decreasing in the movement direction of the typhoon, bring the forecasted typhoon moving direction closer to its real path. The assimilation of cloud-affected satellite microwave brightness temperatures can provide better analysis fields that are more similar to the actual situation. Furthermore, typhoon prediction accuracy is improved using these assimilation analysis fields as the initial forecast fields in NWP models. 展开更多
关键词 atmospheric sounding microwave remote sensing data assimilation cloudy radiances GSI
下载PDF
Review on retrieval of lunar regolith thickness by active and passive microwave measurements 被引量:3
18
作者 Zhiguo MENG Shengbo CHEN Cai LIU Xiaojuan DU Tao MENG Zijun WANG Hang LU 《Global Geology》 2008年第2期102-109,共8页
It is one of the important methods to retrieve lunar regolith thickness using active and passive microwave techniques.The retrieval of lunar regolith thickness is based on microwave radiation transfer process simulati... It is one of the important methods to retrieve lunar regolith thickness using active and passive microwave techniques.The retrieval of lunar regolith thickness is based on microwave radiation transfer process simulation in the regolith media.The lunar regolith model is first introduced,and the features of the involved physical parameters are indicated thereafter,such as dielectric constants,surface roughness,particle size and thermal grads of the lunar regolith.The time delay and the migration of the radar echoes from the different interfaces is the key problem for active microwave measurement.And the simulation of the microwave radiative transfer in the regolith media is the important technique for the passive microwave measurement.The important parameters and the physical mechanism for the two measurements are also presented. 展开更多
关键词 passive microwave remote sensing lunar regolith layer thickness radiative transfer equation layered lunar regolith model
下载PDF
Soil-Vegetation-Atmosphere Radiative Transfer Model in Microwave Region
19
作者 JIA Yuanyuan LI Zhaoliang 《Chinese Geographical Science》 SCIE CSCD 2008年第2期171-177,共7页
The radiative transfer is one of the significant theories that describe the processes of scattering, emission, and absorption of electromagnetic radiant intensity through scattering medium. It is the basis of the stud... The radiative transfer is one of the significant theories that describe the processes of scattering, emission, and absorption of electromagnetic radiant intensity through scattering medium. It is the basis of the study on the quan-titative remote sensing. In this paper, the radiative characteristics of soil, vegetation, and atmosphere were described respectively. The numerical solution of radiative transfer was accomplished by Successive Orders of Scattering (SOS). A radiative transfer model for simulating microwave brightness temperature over land surfaces was constructed, de-signed, and implemented. Analyzing the database generated from soil-vegetation-atmosphere radiative transfer model under Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) configuration showed that the atmospheric effects on microwave brightness temperature should not be neglected, particularly for higher frequency, and can be parameterized. At the same time, the relationship between the emissivities of the different channels was developed. The study results will promote the development of algorithm to retrieve geophysical parameters from mi-crowave remotely sensed data. 展开更多
关键词 soil-vegetation-atmosphere system radiative transfer model microwave remote sensing
下载PDF
A review of underlying topography estimation over forest areas by In SAR: Theory, advances, challenges and perspectives 被引量:7
20
作者 XIE Yan-zhou ZHU Jian-jun +1 位作者 FU Hai-qiang WANG Chang-cheng 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第4期997-1011,共15页
The paramount importance and multi-purpose applications of underlying topography over forest areas have gained widespread recognition over recent decades, bringing about a variety of experimental studies on accurate u... The paramount importance and multi-purpose applications of underlying topography over forest areas have gained widespread recognition over recent decades, bringing about a variety of experimental studies on accurate underlying topography mapping. The highly spatial and temporal dynamics of forest scenarios makes traditional measuring techniques difficult to construct the precise underlying topography surface. Microwave remote sensing has been demonstrated as a promising technique to retrieve the underlying topography over large areas within a limited period, including synthetic aperture radar interferometry(InSAR), polarimetric InSAR(PolInSAR) and tomographic SAR(TomoSAR). In this paper, firstly, the main principle of digital elevation model(DEM) generation by InSAR and SAR data acquisition over forest area are introduced. Following that, several methods of underlying topography extraction based on InSAR, PolInSAR, and TomoSAR are introduced and analyzed, as well as their applications and performance are discussed afterwards. Finally, four aspects of challenge are highlighted, including SAR data acquisition, error compensation and correction, scattering model reconstruction and solution strategy of multi-source data, which needs to be further addressed for robust underlying topography estimation. 展开更多
关键词 underlying topography microwave remote sensing INSAR POLINSAR TomoSAR
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部