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11 results on '"Pan, Linjun"'

7. Turbulence parameters measured by the Beijing Mesosphere-Stratosphere-Troposphere radar in the troposphere/lower stratosphere with three models: Comparison and analyses.

Author

Chen, Ze, Tian, Yufang, Wang, Yinan, Bi, Yongheng, Wu, Xue, Huo, Juan, Pan, Linjun, Wang, Yong, and Lü, Daren

Subjects
ATMOSPHERIC turbulence, VERTICAL wind shear, WIND speed, TURBULENCE, WIND shear, STRATOSPHERE, TURBULENT diffusion (Meteorology)
Abstract

Based on the quality-controlled observational spectral width data of the Beijing Mesosphere-Stratosphere-Troposphere (MST) radar in the altitudinal range of 3-19.8 km from 2012 to 2014, this paper analyzes the relationship between the proportion of negative turbulent kinetic energy (N-TKE) and the horizontal wind speed/horizontal wind vertical shear domain, and gives the distributional characteristics of atmospheric turbulence parameters obtained by using different calculation models. Three calculation models of the spectral width method were used in this study--namely, the H model (Hocking, 1985), N-2D model (Nastrom, 1997) and D-H model (Dehghan and Hocking, 2011). The results showed that the proportion of N-TKE in the H model increases with the horizontal wind speed and/or the vertical shear of horizontal wind speed, up to 80 %. When the horizontal wind speed is greater than 40 m·s-1, the proportion of N-TKE in the H model is greater than 60 %, and thus the H model is not applicable. When the horizontal wind speed is greater than 20 m s-1, the proportion of N-TKE in the N-2D model and D-H model increases with the horizontal wind speed, independent of the vertical shear of the horizontal wind speed, and the maximum values are 2 % and 4 %, respectively. However, it is still necessary to consider the applicability of the N-2D model and D-H model in some weather processes with strong winds. The distributional characteristics with height of the turbulent kinetic energy dissipation rate and the vertical eddy diffusion coefficient Kz derived by the three models are consistent with previous studies. Still, there are differences in the values of turbulence parameters. Also, the range resolution of the radar has little effect on the differences in the range of turbulence parameters' values. The median values of in the H model, N-2D model and D-H model are 10-3.2-10-2.8 m2 s-3, 10-2.8-10-2.4 m2 s-3 and 10-3.0-10-2.5 m2 s-3, respectively. The median values of Kz in these three models are 100.18-100.67 m2 s-1, 100.57-100.90 m2 s-1 and 100.44-100.74 m2 s-1. [ABSTRACT FROM AUTHOR]

Published
2022
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11. A new method for retrieving equivalent cloud base height and equivalent emissivity by using ground-based high-resolution infrared radiance.

Author

Pan, LinJun and Lu, DaRen

Subjects
*CLOUD dynamics, *INFRARED radiometry, *INFORMATION processing, *INTERFEROMETRY, *ALGORITHMS, *ATMOSPHERIC models, *EMISSIVITY, *METEOROLOGICAL observations
Abstract

Based on the ground-based high-resolution infrared radiances observed by the Atmospheric Emitted Radiance Interferometer (AERI), a new method is proposed to identify the clear sky. Meanwhile, we also develop the new algorithms for retrieving the zenith equivalent cloud base height (CBHe) and the equivalent emissivity ([variant_greek_epsilon]e), respectively. The retrieval results in Shouxian indicate that the differences between the CBHe and observational cloud base height (CBH) are much smaller for thick low cloud, and increase with the increasing CBH. The average [variant_greek_epsilon]e for the low, middle, and high cloud is 0.967, 0.781, and 0.616 for the 50 cases, respectively. It decreases with the increasing CBH. The new methods will be useful for studying the role of cloud in the radiation budget in the window region and cloud parameterizations in the climate model. [ABSTRACT FROM AUTHOR]

Published
2013
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