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1. chinaXiv:201703.00308 [pdf]

Target brightness temperature simulation and analysis for the geostationary interferometric microwave sounder (GIMS)

Zhang, Ying; Liu, Hao; Wu, Ji; He, Jieying; Zhang, Cheng
Subjects: Geosciences >> Space Physics

Target brightness temperature maps can be used in geostationary interferometric microwave sounder (GIMS) system simulation. System simulation with accurate target brightness temperature maps can evaluate system performance in near real case and thus help adjust design parameters for the sensor before it is finally put into use. In this paper, method of simulating target brightness temperature using Weather Research and Forecasting Model and Radiative Transfer for TOVS (RTTOV) has been discussed. Target brightness temperature simulation results at oxygen absorption band and water-vapor absorption band have been presented. Some preliminary analyses of simulated brightness temperature for GIMS' observation have also been given.

submitted time 2017-03-10 Hits13597Downloads762 Comment 0

2. chinaXiv:201703.00298 [pdf]

A deblurring method for dynamic target observation of the geostationary interferometric microwave sounder (GIMS)

Zhang, Ying; Liu, Hao; Wu, Ji; Zhang, Cheng; He, Jieying
Subjects: Geosciences >> Space Physics

Brightness temperature change of observation target in one imaging period will introduce image blur to the retrieved image of geostationary interferometric microwave sounder (GIMS), which uses rotating circular array to realize time-sharing sampling other than snap-shot to reduce system complexity but meanwhile resulting in a relatively long imaging period. In this paper, an interpolation method utilizing time sequence of visibilities collected by time-sharing sampling is presented. The method is verified through a simulation system that simulates GIMS's observation process in viewing a series of near real case brightness temperature maps modeled by FNL/WRF/RTTOV method. Results show that the interpolation method can de-blur the image and reduce imaging error to the degree of snap-shot imaging. �2016 IEEE.

submitted time 2017-03-10 Hits1241Downloads395 Comment 0

3. chinaXiv:201703.00291 [pdf]

Analysis and simulation of GIMS observation on dynamic targets

Zhang, Ying; Liu, Hao; Wu, Ji; Zhang, Cheng; He, Jieying
Subjects: Geosciences >> Space Physics

Imaging period is an important consideration to geostationary interferometric microwave sounder (GIMS) when mapping fast changing target such as typhoon. GIMS simulation system with near real case observation target can evaluate system performance in different system configurations and thus help determine the optimal imaging period. In this paper, GIMS simulation system using MATLAB and near real case observation modeled by FNL/WRF/RTTOV method has been used to analyze the effect of imaging period on image quality. System simulation results for each frequency channel will be presented and analyses of imaging period's effect on image quality will also be given. �2016 IEEE.

submitted time 2017-03-10 Hits1188Downloads364 Comment 0

4. chinaXiv:201703.00286 [pdf]

Temperature and humidity profiles retrieving over land using clear sky measurements of microwave humidity-temperature sounder on Chinese FY-3C satellite

He, Qiurui; Wang, Zhenzhan; He, Jieying
Subjects: Geosciences >> Space Physics

An one-dimensional variational retrieval system was developed to retrieve the clear sky atmospheric temperature and humidity profiles over land using the measurements of microwave humidity-temperature sounder (MWHTS) on Chinese FY-3C satellite. The system parameters are configured by analyzing the MWHTS channel properties and the climate condition over land. The retrieval results are evaluated by root mean square error (rmse) with respect to European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data. The validated results show that the maximum root mean square error of temperature and humidity are 2.59K and 11.87%, respectively. The retrieval results, compared with National Centers for Environmental Prediction (NCEP) 6 hour forecast profiles, show that the background profiles can affect the accuracy of retrieval profiles and FY-3C/MWHTS measurements can improve forecast precision of humidity. �2016 IEEE.

submitted time 2017-03-10 Hits3182Downloads396 Comment 0

5. chinaXiv:201703.00257 [pdf]

Precipitation Retrievals in typhoon domain combining of FY3C MWHTS Observations and WRF Predicted Models

HE Jieying; ZHANG Shengwei; LI Na
Subjects: Geosciences >> Space Physics

A passive sub-millimeter precipitation retrievals algorithm is provided based on Microwave Humidity and Temperature Sounder (MWHTS) onboard the Chinese Feng Yun 3C (FY-3C) satellite. Using the validated global reference physical model NCEP/WRF/ VDISORT), NCEP data per 6 hours are downloaded to run the Weather Research and Forecast model WRF, and derive the typical precipitation data from the whole world. The precipitation retrieval algorithm can operate either on land or on seawater for global. To simply the calculation procedure and save the training time, principle component analysis (PCA) was adapted to filter out the redundancy caused by scanning angle and surface effects, as well as system noise. According to the comparison and validation combing with other precipitation sources, it is demonstrated that the retrievals are reliable for surface precipitation rate higher than 0.1 mm/h at 15km resolution.

submitted time 2017-03-10 Hits256Downloads155 Comment 0

6. chinaXiv:201703.00254 [pdf]

Effects of a cloud filtering method for Fengyun-3C Microwave Humidity and Temperature Sounder measurements over ocean on retrievals of temperature and humidity

HE Qiurui; WANG Zhenzhan; HE Jieying
Subjects: Geosciences >> Space Physics

For Microwave Humidity and Temperature sounder (MWHTS) measurements over ocean, a cloud filtering method is presented to filter out cloud- and precipitation-affected observations by analyzing the sensitivity of the simulated brightness temperatures of MWHTS to cloud liquid water, and using the root mean square error (RMSE) between observation and simulation in clear sky as a reference standard. The atmospheric temperature and humidity profiles are retrieved using MWHTS measurements with and without filtering by multiple linear regression (MLR), artificial neural networks (ANN) and one-dimensional variational (1DVAR) retrieval methods, respectively, and the effects of the filtering method on the retrieval accuracies are analyzed. The numerical results show that the filtering method can improve the retrieval accuracies of the MLR and the 1DVAR retrieval methods, but have little influence on that of the ANN. In addition, the dependencies of the retrieval methods upon the testing samples of brightness temperature are studied, and the results show that the 1DVAR retrieval method has great stability due to that the testing samples have great impact on the retrieval accuracies of the MLR and the ANN, but have little impact on that of the 1DVAR.

submitted time 2017-03-10 Hits407Downloads230 Comment 0

7. chinaXiv:201605.00290 [pdf]

RESEARCH ON GLOBAL PROFILES AND PRECIPITATION RETRIEVALS FOR FY-3C MWHTS

He, Jieying; Zhang, Shengwei
Subjects: Geosciences >> Space Physics

The paper develops a passive sub-millimeter atmospheric profile and precipitation retrievals algorithm for Microwave Humidity and Temperature Sounder (MWHTS) onboard the Chinese Feng Yun 3C (FY-3C) satellite. The retrieval algorithm employs a number of neural network estimators trained and evaluated using the validated global reference physical model NCEP/WRF/ARTS, and works for land and seawater with latitude between -30 to 30 degree. To simply the calculation procedure and save the training time, principle component analysis was adapted to filter out the redundancy caused by scanning angle and surface effects, as well as system noise. NCEP data per 6 hours are downloaded to run the Weather Research and Forecast model WRF, and derive the typical precipitation data from the whole world. The Atmospheric Radiative Transfer Simulator ARTS is feasible for performing simulations of atmospheric radiative transfer.

submitted time 2016-05-03 Hits387Downloads253 Comment 0

8. chinaXiv:201605.00283 [pdf]

TARGET BRIGHTNESS TEMPERATURE SIMULATION AND ANALYSIS FOR THE GEOSTATIONARY INTERFEROMETRIC MICROWAVE SOUNDER (GIMS)

Zhang, Ying; Liu, Hao; Wu, Ji; He, Jieying; Zhang, Cheng
Subjects: Geosciences >> Space Physics

Target brightness temperature maps can be used in geostationary interferometric microwave sounder (GIMS) system simulation. System simulation with accurate target brightness temperature maps can evaluate system performance in near real case and thus help adjust design parameters for the sensor before it is finally put into use. In this paper, method of simulating target brightness temperature using Weather Research and Forecasting Model and Radiative Transfer for TOVS (RTTOV) has been discussed. Target brightness temperature simulation results at oxygen absorption band and water-vapor absorption band have been presented. Some preliminary analyses of simulated brightness temperature for GIMS' observation have also been given.

submitted time 2016-05-03 Hits588Downloads376 Comment 0

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