- 标题
- 摘要
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- 实验方案
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Soil Moisture Retrieval by Combining Using Active and Passive Microwave Data
摘要： Active and passive microwave remote sensing have their particular characteristics. Active microwave is more sensitive to vegetation cover and surface soil roughness, while passive microwave is more sensitive to the surface soil moisture. A new retrieval algorithm has been proposed by using Aquarius and SMAP satellites’ active and passive microwave observations to retrieve soil moisture products in different spatial scales. The retrieval results of soil moisture have been verified with the ground observations of soil moisture and temperature measurement (SMTM) stations in Naqu, China. The advantages and disadvantages of the algorithm have also been evaluated to analyze the practical value of the new soil moisture retrieval algorithm.
关键词： soil moisture retrieval algorithm,passive microwave,soil moisture,active microwave,active and passive microwave remote sensing,Aquarius satellite
更新于2025-09-23 15:21:01
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Light Bullets in Passively Mode-Locked Lasers: Dynamics and Instabilities
摘要： Vertically and horizontally inhomogeneous distributions of hydrometeors are often observed in precipitating clouds. The 3-D characteristics can then cause errors in the passive microwave rainfall measurements with the current off-nadir viewing sensors’ specific specifications. This result is due to the fact that the same surface rainfall could be associated with different amounts of hydrometeors depending on the sensors’ viewing paths. In this paper, we confirmed that the plane-parallel radiative treatment to the atmosphere leaves a notable deficiency in the microwave radiometric signatures, particularly at the higher frequency channels for different viewing directions when largely inhomogeneous precipitating clouds are accompanied by significant ice particles. The mean differences between the two brightness temperature fields with two opposite azimuthal viewing directions were up to approximately 40 ?K for the vertically polarized channel at 85.5 GHz in the case study. The impact of the 3-D effect on the passive microwave rainfall estimations was also examined by synthetic retrievals employing a Bayesian methodology. The results showed that the uncertainty in the rainfall estimations due to the 3-D effect depended on the viewing directions considered in the a priori information. It was also found that taking more viewing angles or the azimuth angles in the a priori information into consideration tended to moderate the retrieval difference that resulted from the different viewing directions. In addition, the retrieval uncertainty related to the 3-D effect appeared to be more significant for heavy rainfall cases with large amounts of ice particles, as expected.
关键词： 3-D radiative transfer,precipitation,3-D effect,Passive microwave remote sensing
更新于2025-09-23 15:21:01
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Estimation of 1-Km All-Weather Land Surface Temperature Over the Tibetan Plateau
摘要： Land surface temperature (LST) immensely affects the energy balance and water cycle on the earth’s surface. Merging thermal infrared (TIR) and passive microwave (MW) remote sensing provides the possibility to obtain all-weather LST with moderate resolutions. However, due to difficulties in downscaling MW LST, current methods merging TIR LST and MW LST into such an all-weather LST are limited over large areas with very complicated land surfaces (e.g. the Tibetan Plateau). By fully considering the influence of the topography on estimation of merged LSTs, this study revises the recently-developed physical method for generating the 1-km all-weather LST and applies it over the Tibetan Plateau to merge MODIS (1 km) and AMSR2 (10 km) observations. Results show that the merged LST has accuracy of 0.99 K-3.22 K when validated against in-situ LSTs from five ground stations with various land cover types. This study would be beneficial for continuously monitoring LST and improving spatio-temporal resolutions for associated land surface process studies requiring high-quality all-weather LST over large scales.
关键词： MODIS,Spatial correlations,AMSR2,Land surface temperature (LST),Passive microwave remote sensing
更新于2025-09-23 15:21:01
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Micro-transfer-printing of InP Photonic Devices to Silicon Photonics
摘要： Vertically and horizontally inhomogeneous distributions of hydrometeors are often observed in precipitating clouds. The 3-D characteristics can then cause errors in the passive microwave rainfall measurements with the current off-nadir viewing sensors’ speci?cations. This result is due to the fact that the same surface rainfall could be associated with different amounts of hydrometeors depending on the sensors’ viewing paths. In this paper, we con?rmed that the plane-parallel radiative treatment to the atmosphere leaves a notable de?ciency in the microwave radiometric signatures, particularly at the higher frequency channels for different viewing directions when largely inhomogeneous precipitating clouds are accompanied by signi?cant ice particles. The mean differences between the two brightness temperature ?elds with two opposite azimuthal viewing directions were up to approximately 40 ?K for the vertically polarized channel at 85.5 GHz in the case study. The impact of the 3-D effect on the passive microwave rainfall estimations was also examined by synthetic retrievals employing a Bayesian methodology. The results showed that the uncertainty in the rainfall estimations due to the 3-D effect depended on the viewing directions considered in the a priori information. It was also found that taking more viewing angles or the azimuth angles in the a priori information into consideration tended to moderate the retrieval difference that resulted from the different viewing directions. In addition, the retrieval uncertainty related to the 3-D effect appeared to be more signi?cant for heavy rainfall cases with large amounts of ice particles, as expected.
关键词： 3-D radiative transfer,precipitation,3-D effect,Passive microwave remote sensing
更新于2025-09-23 15:19:57
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Novel Square-Waveguide Dual-Mode Two-Way Reactive Power Divider
摘要： Vertically and horizontally inhomogeneous distributions of hydrometeors are often observed in precipitating clouds. The 3-D characteristics can then cause errors in the passive microwave rainfall measurements with the current off-nadir viewing sensors’ specific specifications. This result is due to the fact that the same surface rainfall could be associated with different amounts of hydrometeors depending on the sensors’ viewing paths. In this paper, we confirmed that the plane-parallel radiative treatment to the atmosphere leaves a notable deficiency in the microwave radiometric signatures, particularly at the higher frequency channels for different viewing directions when largely inhomogeneous precipitating clouds are accompanied by significant ice particles. The mean differences between the two brightness temperature fields with two opposite azimuthal viewing directions were up to approximately 40 ?K for the vertically polarized channel at 85.5 GHz in the case study. The impact of the 3-D effect on the passive microwave rainfall estimations was also examined by synthetic retrievals employing a Bayesian methodology. The results showed that the uncertainty in the rainfall estimations due to the 3-D effect depended on the viewing directions considered in the a priori information. It was also found that taking more viewing angles or the azimuth angles in the a priori information into consideration tended to moderate the retrieval difference that resulted from the different viewing directions. In addition, the retrieval uncertainty related to the 3-D effect appeared to be more significant for heavy rainfall cases with large amounts of ice particles, as expected.
关键词： 3-D radiative transfer,precipitation,3-D effect,Passive microwave remote sensing
更新于2025-09-19 17:13:59
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SCATTERING AND TRANSMISSION OF WAVES IN MULTIPLE RANDOM ROUGH SURFACES: ENERGY CONSERVATION STUDIES WITH THE SECOND ORDER SMALL PERTURBATION METHOD
摘要： Energy conservation is an important consideration in wave scattering and transmission from random rough surfaces and is particularly important in passive microwave remote sensing. In this paper, we study energy conservation in scattering from layered random rough surfaces using the second order small perturbation method (SPM2). SPM2 includes both first order incoherent scattering and a second order correction to the coherent fields. They are combined to compute the total reflected and transmitted powers, as a sum of integrations over wavenumber kx, in which each integration includes the surface power spectra of a rough interface weighted by an emission kernel function (assuming the roughness of each interface is uncorrelated). We calculate the corresponding kernel functions which are the power spectral densities for one-dimensional (1D) surfaces in 2D scattering problems and examine numerical results for the cases of 2 rough interfaces and 51 rough interfaces. Because it is known that the SPM when evaluated to second order conserves energy, and it can be applied to second order for arbitrary surface power spectra, energy conservation can be shown to be satisfied for each value of kx in the kernel functions. The numerical examples show that energy conservation is obeyed for any dielectric contrast, any layer configuration and interface, and arbitrary roughness spectra. The values of reflected or transmitted powers predicted, however, are accurate only to second order in small surface roughness.
关键词： roughness spectra,wave scattering,random rough surfaces,SPM2,transmission,passive microwave remote sensing,layered random rough surfaces,small perturbation method,power spectral densities,Energy conservation,dielectric contrast
更新于2025-09-10 09:29:36