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Open AccessArticle

An Improved Iterative Fitting Method to Estimate Nocturnal Residual Layer Height

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State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing (LIESMARS), Wuhan University, Wuhan 430079, China
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Collaborative Innovation Center for Geospatial Technology, Wuhan 430079, China
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Hubei Collaborative Innovation Center for High-Efficiency Utilization of Solar Energy, Wuhan 430068, China
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School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China
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Authors to whom correspondence should be addressed.
Academic Editor: Robert W. Talbot
Atmosphere 2016, 7(8), 106; https://doi.org/10.3390/atmos7080106
Received: 8 July 2016 / Revised: 8 August 2016 / Accepted: 12 August 2016 / Published: 17 August 2016
The planetary boundary layer (PBL) is an atmospheric region near the Earth’s surface. It is significant for weather forecasting and for the study of air quality and climate. In this study, the top of nocturnal residual layers—which are what remain of the daytime mixing layer—are estimated by an elastic backscatter Lidar in Wuhan (30.5°N, 114.4°E), a city in Central China. The ideal profile fitting method is widely applied to determine the nocturnal residual layer height (RLH) from Lidar data. However, the method is seriously affected by an optical thick layer. Thus, we propose an improved iterative fitting method to eliminate the optical thick layer effect on RLH detection using Lidar. Two typical case studies observed by elastic Lidar are presented to demonstrate the theory and advantage of the proposed method. Results of case analysis indicate that the improved method is more practical and precise than profile-fitting, gradient, and wavelet covariance transform method in terms of nocturnal RLH evaluation under low cloud conditions. Long-term observations of RLH performed with ideal profile fitting and improved methods were carried out in Wuhan from 28 May 2011 to 17 June 2016. Comparisons of Lidar-derived RLHs with the two types of methods verify that the improved solution is practical. Statistical analysis of a six-year Lidar signal was conducted to reveal the monthly average values of nocturnal RLH in Wuhan. A clear RLH monthly cycle with a maximum mean height of about 1.8 km above ground level was observed in August, and a minimum height of about 0.7 km was observed in January. The variation in monthly mean RLH displays an obvious quarterly dependence, which coincides with the annual variation in local surface temperature. View Full-Text
Keywords: boundary layer; atmosphere; Lidar boundary layer; atmosphere; Lidar
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Wang, W.; Gong, W.; Mao, F.; Pan, Z. An Improved Iterative Fitting Method to Estimate Nocturnal Residual Layer Height. Atmosphere 2016, 7, 106.

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