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Fan X.,PLA University of Science and Technology | Fan X.,Chinese Academy of Sciences | Weng L.,PLA University of Science and Technology | Weng L.,Chinese Academy of Sciences | And 4 more authors.
Science China Technological Sciences | Year: 2014

The nightly mean mesospheric temperature profiles between 80 and 107 km, observed by Na lidar, over Fort Collins, Colorado (41°N, 105°W) from 1990 to 2010, are employed to research the temporal and spatial variations and mesopause. We find that the maximum mean temperature is in summer months above 95 km, but reverse below 95 km, and there is a cooler region below 185 K around 97 km in August. The largest seasonal variation is 39.2 K at 81 km, and the minimum is 6.5 K at 96.5 km. The maximum standard derivation in spring and autumn months are larger than other seasons above 105 km, but the temperatures in March, June and September are lower than the other months between 82 km and 100 km where winter is the largest season. Moreover, the seasonal variations of the temperature are about 36, 8 and 21 K at 85, 95 and 105 km, respectively. winter is colder and summer is warmer above 97.5 km, but reverse below 92 km. The mesopause height is around 102 km in winter, but 84 km in summer, and the mean speed of decreasing or increasing of the mesopause height is about 5 km/month in spring and autumn months which are about 90 km. The lasting time of the mesopause in winter is near 6 months, longer than other seasons, and the mesopause temperature is about 165 K in cool summer, and 185 K in warm winter. © 2014 Science China Press and Springer-Verlag Berlin Heidelberg.


Lu W.,PLA University of Science and Technology | Yan W.,PLA University of Science and Technology | Ai W.-H.,PLA University of Science and Technology | Ai W.-H.,Nanjing University of Information Science and Technology | Shi J.-K.,Unit 63655 of PLA
Wuli Xuebao/Acta Physica Sinica | Year: 2013

In this paper, we simulated the earth scene brightness temperature by creating the earth scene data sets and using polarimetric microwave radiative transfer model. On the basis of the fully polarized antenna temperature equation we have derived, the radiometer antenna temperature was also simulated by generating antenna pattern through GRASP9 software. Then by using multiple linear regression method, the M matrix was calculated and the antenna cross-polarization correction for spaceborne polarimetric microwave correlation radiometer was realized. The correction results show that the antenna temperature and earth scene brightness temperature have a linear relationship. Antenna cross-polarization influences the orthogonal channels brightness temperature seriously, especially the vertical polarization brightness temperature. The antenna cross-polarization for each channel has been effectively reduced. Residual cross-polarization is better than -23 dB and the polarization purity is greater than 99.5%. Correction of using M matrix to eliminate the antenna cross-polarization is feasible. It has been proved that this technique is most appropriate for the final correction of antenna cross-polarization for the spaceborne polarimetric microwave correlation radiometer on orbit. © 2013 Chinese Physical Society.


Chen X.,National University of Defense Technology | Yi G.,Unit 63655 of PLA
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2012

By virtue of polynomial theory, the near-ground atmospheric turbulence was simulated, which was compared with the near-ground atmospheric turbulence measured by the two-point theory based on temperature fluctuation principle in experimental field. Firstly, the work could take full advantage of the measured meteorological parameters at the experimental site such as temperature, humidity and pressure to carry through the simulation experiment, which provided advantage for the research work. Secondly, practical scientific results could be obtained by the work. In this paper, it focused on the research of correlation between measured turbulence and simulated turbulence by the polynomial theory on condition of relatively high humidity and related changes after refitting polynomial coefficients, and the uncertainty of near-ground atmospheric turbulence measured by the two-point theory was studied. The results show that a strong correlation exists between near-ground atmospheric turbulence simulated by the polynomial theory with near-ground atmospheric turbulence measured by the two-point theory on condition of relatively high humidit. And both can maintain a high stability. But when the relative humidity arrives at 80% or more, the correlation debases significantly, even presents negative value, which proves that the near-ground atmospheric turbulence measured by the two-point theory has greater uncertainty under the condition of relatively high humidity (80% or more).


Shi J.-K.,Unit 63655 of PLA | Lu W.,PLA University of Science and Technology | Yan W.,PLA University of Science and Technology | Ai W.-H.,PLA University of Science and Technology | Ai W.-H.,Nanjing University of Information Science and Technology
Wuli Xuebao/Acta Physica Sinica | Year: 2013

Spaceborne polarimetric microwave correlation radiometer is a new type of instrument for the passive microwave remote sensing from space, which can provide an important way for remote sensing of sea surface wind vector and other ocean atmosphere environmental parameters. Antenna cross-polarization correction is an important part of the data pre-processing algorithm. In this paper, for the demand of antenna cross-polarization correction in spaceborne polarimetric microwave correlation radiometer, we have indepen-dently derived the full polarization antenna temperature equation based on the polarization coherent detection theory and the definition of Stokes parameters. The equation for the four parameters of Stokes antenna temperature introduced the cross polarization amplitude and phase between the Stokes parameters. Besides, the influence of the polarization rotation angle on the antenna pattern computation was considered. Finally, we established a geometric correspondence between the antenna scanning beam and the earth scene. The principle for determining the parameters of the antenna temperature equation was also discussed. Stokes antenna temperature equation laid the foundation for antenna cross-polarization correction for spaceborne polarimetric microwave correlation radiometer in the future. © 2013 Chinese Physical Society.


Liu Z.,Unit 63655 of PLA | Wang J.,Unit 63655 of PLA | Wu Y.,Unit 63655 of PLA | Xiong L.,Unit 63655 of PLA | Qian K.,Unit 63655 of PLA
Chinese Control Conference, CCC | Year: 2013

Aiming at the outlier influencing the data processing and analyzing in the observation sequence of measurement and control fields, the precision of data processing will be decline or radiation by using the standard Kalman filter. So a method on Kalman Filter Outlier Detection Methods Based on M -estimation was proposed. Firstly, the prediction data of next time was estimated by using the adaptive recursive M-estimation; and the real measured data and the estimation data; then the remaining error was into the Kalman equation. Thirdly, whether the outlier was existed was judged by using the measured data. The results and simulation shows that the methods was robustness, and had the immunity to not only the single outlier but also a series of outliers no more than 15; and the threshold δ was not initialized; the precision of outlier detection could be enhanced. © 2013 TCCT, CAA.

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