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Research on microwave radiation features and lunar regolith parameters inversion of the Rümker region

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Science China Earth Sciences 2021年第6期64卷 1005-1014页

作者： Xueying wang zhenzhan wang Jingshan JIANG Dehai ZHANG Key Laboratory of Microwave Remote Sensing National Space Science CenterChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

Chang'e-5(CE-5)mission is expected to land and sample in the Rümker region,north of the Oceanus *** select optimal sampling points,the microwave radiation features in this mare unit are analyzed,and the dielectric constant and thickness of lunar regolith are retrieved based on Chang'e lunar microwave sounder(CELMS)*** to the microwave brightness temperature(TB)maps,TB varying with frequency at noon and midnight are different,in which noon TB increases with frequency,but midnight TB does not follow this ***,there are differences among TB distributions at the three higher frequencies,especially in the southern *** addition,a great TB difference between noon and midnight can be seen in Rümker E that shows higher daytime temperature but lower nighttime *** inversion results reveal that the dielectric constant is lower in the west and north,higher in the middle and east,and the largest value occurs in Rümker *** for the regolith thickness,most areas are uniform and no more than 4 m,with the thickest and thinnest regolith appearing in the northwest and Rümker E,no less than 6 m and about 2.5 m,*** the safety and operability of landing and sampling,the northwest with thick regolith is recommended,while the Rümker E should be eluded.

关键词： Rümker region Microwave sounder Brightness temperature Lunar regolith dielectric constant Lunar regolith thickness

Simulations on the influence of lunar surface temperature profiles on CE-1 lunar microwave sounder brightness temperature

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Science China Earth Sciences 2010年第9期53卷 1379-1391页

作者： LI Yun wang zhenzhan JIANG JingShan National Microwave Remote Sensing Laboratory Center for Space Science and Applied ResearchChinese Academy of SciencesBeijing 100190China Graduate University of Chinese Academy of Sciences Beijing 100049China

Surface temperature profile is an important parameter in lunar microwave remote sensing. Based on the analysis of physical properties of the lunar samples brought back by the Apollo and Luna missions, we modeled temporal and spatial variation of lunar surface temperature with the heat conduction equation, and produced temperature distribution in top 6.0 m of lunar regolith of the whole Moon surface. Our simulation results show that the profile of lunar surface temperature varies mainly within the top 20 cm, except at the lunar polar regions where the changes can reach to about 1.0 m depth. The temperature is stable beyond that depth. The variations of lunar surface temperature lead to main changes in brightness temperature (TB) at different channels of the lunar microwave sounder (CELMS) on Chang'E-1 (CE-1). The results of this paper show that the temperature profile influenced CELMS TB, which provides strong validation on the CELMS data, and lays a solid basis for future interpretation and utilization of the CELMS data.

关键词： CE-1 lunar Microwave Sounder (CELMS) lunar surface temperature lunar surface temperature profile heat conduction equation simulation of brightness temperature

Retrieving capillary-gravity wave spectrum from polarimetric microwave radiation of ocean surface

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Science China Earth Sciences 2010年第6期53卷 901-910页

作者： YIN XiaoBin wang zhenzhan LIU YuGuang Center for Space Science and Applied Research Chinese Academy of SciencesBeijing 100190China Physical Oceanography Laboratory Ocean University of ChinaQingdao 266100China

A new simple two-scale model on the polarimetric microwave emission of ocean surface is derived at first, which can be ex-pressed as an integral of weighting functions (M0 and M2) and ocean surface curvature spectrum coefficients (C0 and C2). This provides a simple way to investigate the effect of curvature spectrum on ocean emission. It is found that ocean waves with wavelengths both comparable to and much greater than the electromagnetic wavelength can contribute to the harmonics of ocean surface microwave emission, depending on the magnitude of the ocean surface spectrum in these length scales. Bright-ness temperature predictions differ significantly due to present diverse spectrum models, and thus a study on wave spectrum obtained inversely from brightness temperature measurements is necessary. From the ocean surface radiation data measured by polarimetric microwave radiometer, we derived an ocean wave spectrum with a wider wave number range, using the proposed two-scale model and constrained linear least-squares method. The derived ocean wave spectrum is useful for comparing with present diverse models.

关键词： microwave radiation of ocean surface two-scale model ocean wave curvature spectrum

Quantifying the contribution of natural variability to September Arctic sea ice decline

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Acta Oceanologica Sinica 2016年第5期35卷 49-53页

作者： SONG Mirong WEI Lixin wang zhenzhan State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences Key Laboratory of Research on Marine Hazards Forecasting National Marine Environmental Forecasting CenterState Oceanic Administration Key Laboratory of Microwave Remote Sensing National Space Science CenterChinese Academy of Sciences

Arctic sea ice extent has been declining in recent decades. There is ongoing debate on the contribution of natural internal variability to recent and future Arctic sea ice changes. In this study, we contrast the trends in the forced and unforced simulations of carefully selected global climate models with the extended observed Arctic sea ice records. The results suggest that the natural variability explains no more than 42.3% of the observed September sea ice extent trend during 35 a（1979–2013） satellite observations, which is comparable to the results of the observed sea ice record extended back to 1953（61 a, less than 48.5% natural variability）. This reinforces the evidence that anthropogenic forcing plays a substantial role in the observed decline of September Arctic sea ice in recent decades. The magnitude of both positive and negative trends induced by the natural variability in the unforced simulations is slightly enlarged in the context of increasing greenhouse gases in the 21st ***, the ratio between the realizations of positive and negative trends change has remained steady, which enforces the standpoint that external forcing will remain the principal determiner of the decreasing Arctic sea ice extent trend in the future.

关键词： internal variability sea ice decline external forcing

Estimation of wind speeds inside Super Typhoon Nepartak from AMSR2 low-frequency brightness temperatures

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Frontiers of Earth Science 2019年第1期13卷 124-131页

作者： Lei ZHANG Xiaobin YIN Hanqing SH zhenzhan wang Qing XU Institute of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101China Beijing Piesat Information Technology Co.Ltd Beijing 100195China National Space Science Center Chinese Academy of SciencesBeijing 100190China College of Oceanography Hohai UniversityNanjing 211101China

Accurate estimations of typhoon-level winds are highly desired over the westem Pacific Ocean.A wind speed retrieval algorithm is used to retrieve the wind speeds within Super Typhoon Nepartak (2016)using 6.9- and 10.7-GHz brightness temperatures from the Japanese Advanced Microwave Scanning Radiometer 2 (AMSR2) sensor on board the Global Change Observation Mission-Water 1 (GCOM-Wl)*** results show that the retrieved wind speeds clearly represent the intensification process of Super Typhoon Nepartak.A good agreement is found between the retrieved wind speeds and the Soil Moisture Active Passive wind speed *** mean bias is 0.51 m/s,and the root-mean-square difference is 1.93 m/s between *** retrieved maximum wind speeds are 59.6 m/s at 04:45 UTC on July 6 and 71.3 m/s at 16:58 UTC on July *** two results demonstrate good agreement with the results reported by the China Meteorological Administration and the Joint Typhoon Warning *** addition,Feng-Yun 2G (FY-2G) satellite infrared images,Feng-Yun 3C (FY-3C)microwave atmospheric sounder data,and AMSR2 brightness temperature images are also used to describe the development and structure of Super Typhoon Nepartak.

关键词： microwave radiometer sea surface wind retrieval AMSR2 Nepartak SMAP

Simulations of lunar equatorial regolith temperature profile based on measurements of Diviner on Lunar Reconnaissance Orbiter

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Science China Earth Sciences 2014年第7期57卷 2232-2241页

作者： RAN Zhen wang zhenzhan Key Laboratory of Microwave Remote Sensing National Space Science Center/Center for Space Science and Applied Research Chinese Academy of Sciences University of the Chinese Academy of Sciences

Lunar equatorial regolith temperature profiles were simulated using the half-limited solid heat conduction model. Based on the infrared data measured using the Diviner radiometer on the Lunar Reconnaissance Orbiter launched by the United Sates in June 2009, three factors influencing temperature profiles were analyzed. The infrared brightness temperature data from Diviner channel 7 were used to retrieve surface temperature. In simulating regolith temperature profiles, the retrieved temperature, rather than temperatures calculated from solar radiance at the lunar surface, were used as the input for surface temperature in solving the heat-conductive equation. The results showed that the bottom-layer temperature at depths of 6 m approached almost 246 K after 10000 iterations. The temperature was different to the temperature of 250 K at the same depth encountered in simulations using solar radiance. Simulations from both methods of surface temperatures over a lunar day gave similar variations. At lunar night, the temperature difference between the two was about 2 K; the main differences occurred when the solar elevation angle was very low when surface temperatures are largely affected by terrain topography. With no certainty in lunar temperature profiles at present, the advantage of the retrieval method using infrared sensor data as input to the boundary conditions in solving the lunar heat conduction equation is that simulations of surface temperature variations are more accurate. This is especially true in areas with large variations in terrain topography, where surface temperatures vary greatly because of shading from the sunlight.

关键词： Diviner radiometer equation of heat conduction lunar temperature profile infrared brightness temperature

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Chaos Particle Swarm Optimization Combined with Circular Median Filtering for Geophysical Parameters Retrieval from WindSat

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Journal of Ocean University of China 2016年第4期15卷 593-605页

作者： ZHANG Lei wang zhenzhan SHI Hanqing LONG Zhiyong DU Huadong Institute of Meteorology and Oceanography PLA University of Science and Technology Key Laboratory of Microwave Remote Sensing Chinese Academy of Sciences

This paper established a geophysical retrieval algorithm for sea surface wind vector, sea surface temperature, columnar atmospheric water vapor, and columnar cloud liquid water from WindSat, using the measured brightness temperatures and a matchup database. To retrieve the wind vector, a chaotic particle swarm approach was used to determine a set of possible wind vector solutions which minimize the difference between the forward model and the WindSat observations. An adjusted circular median filtering function was adopted to remove wind direction ambiguity. The validation of the wind speed, wind direction, sea surface temperature, columnar atmospheric water vapor, and columnar liquid cloud water indicates that this algorithm is feasible and reasonable and can be used to retrieve these atmospheric and oceanic parameters. Compared with moored buoy data, the RMS errors for wind speed and sea surface temperature were 0.92 m s^(-1) and 0.88℃, respectively. The RMS errors for columnar atmospheric water vapor and columnar liquid cloud water were 0.62 mm and 0.01 mm, respectively, compared with F17 SSMIS results. In addition, monthly average results indicated that these parameters are in good agreement with AMSR-E results. Wind direction retrieval was studied under various wind speed conditions and validated by comparing to the Quik SCAT measurements, and the RMS error was 13.3?. This paper offers a new approach to the study of ocean wind vector retrieval using a polarimetric microwave radiometer.

关键词： Retrieval retrieval cloud Chaos columnar geophysical brightness retrieve validated swarm

Reprocessing 12-yr Microwave Humidity Sounder Historical Data of Fengyun-3 Satellites

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Journal of Meteorological Research 2022年第2期36卷 261-270页

作者： Yang GUO Fangli DOU Qiong WU Jieying HE Shengwei ZHANG zhenzhan wang Songyan GU Peng ZHANG Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites National Satellite Meteorological Center(National Center for Space Weather)China Meteorological AdministrationBeijing 100081 Innovation Center for Fengyun Meteorological Satellite(FYSIC) China Meteorological AdministrationBeijing 100081 National Space Science Center Chinese Academy of SciencesBeijing 100190

Atmospheric water vapor is an essential climate variable(ECV)with extensive spatial and temporal *** humidity observations from meteorological satellites provide important information for climate system variables,including atmospheric water vapor and precipitable water,and assimilation in numerical weather prediction(NWP)and *** one of the payloads onboard China’s second-generation polar-orbiting operational meteorological Fengyun-3(FY-3)satellites,the Microwave Humidity Sounder(MWHS)has been continuously observing the global humidity since *** reprocessing of historical FY-3 MWHS data is documented in detail in this *** calibrating and correcting the data,the quality of the reprocessed dataset is evaluated and the improvement is shown in this *** results suggest that MWHS observations bias is reduced to approximately 0.8 K,compared with METOP-A Microwave Humidity Sounder(MHS).The temporal variability of MWHS is highly correlated with the instrument *** reprocessing,the scene temperature dependency is mitigated for all 183 GHz channels,and the consistency and stability between FY-3A/B/C are also improved.

关键词： Fengyun-3 Microwave Humidity Sounder historical data reprocessing

Calibration and brightness temperature algorithm of CE-1 Lunar Microwave Sounder (CELMS)

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Science China Earth Sciences 2010年第9期53卷 1392-1406页

作者： zhenzhan wang Yun Li XiaoHui Zhang Jiang JingShan ChuanDong Xu DeHai Zhang WeiGuo Zhang Chinese Acad Sci Natl Microwave Remote Sensing Lab Ctr Space Sci & Appl Res Beijing 100190 Peoples R China

CE-1 Lunar Microwave Sounder (CELMS) is the first passive microwave radiometer in the world to sound the surface of the Moon in the lunar orbit at altitude of 200 km. The scientific objective of CELMS is to obtain global brightness temperature (TB) of the Moon, to retrieve information on lunar regolith, and to evaluate the distribution of helium-3 on the Moon implanted by solar wind. Before launch of CELMS, a series of experiments were carried out in laboratories to test the performances of the systems, and to calibrate the responses between the input of TB and the output of voltage from the receivers. However, the thermal condition exposed to CELMS is more complicated in lunar orbit than on the Earth, which makes the temperatures of different parts of CELMS wave vary greatly, and the cosmic background is not very clean due to the pointing of cold space antenna to the direction of the satellite running, which brings uncertainties into data-processing of CELMS when the temperature of cold space is used as a calibrator. Furthermore, the lack of knowledge on the lunar ingredients and compositions, distributions of physical temperatures, and properties on lunar microwave radiation leads to difficulties in validating the measurements and retrievals of CELMS. By analyzing the results of ground experiments and the measurements of CELMS in-orbit, along with our knowledge of the properties of lunar surface, here we give algorithms on calibration and antenna pattern correction (APC) of CELMS. We also describe in detail the principle of microwave transfer among the elements of CELMS, and discuss the method on testing calibration parameters of the system. In addition, the theory and model on correction antenna pattern of CELMS are developed by comparing antenna temperatures by CELMS with those simulated by microwave radiative transfer models. The global distribution of TB is given and the features of TB are analyzed. Our results show rich information included in TB on the prope

关键词： CE-1 CE-1 Lunar Microwave Sounder/CELMS in-orbit calibration cold space APC algorithm