Planetary boundary layer height from CALIOP compared to radiosonde over China

Wanchun Zhang,Yong Zhang,Panmao Zhai,Yucong Miao,Zhengqiang Li,Jianping Guo,Huan Liu

doi:10.5194/acp-16-9951-2016

Abstract

Abstract. Accurate estimation of planetary boundary layer height (PBLH) is key to air quality prediction, weather forecast, and assessment of regional climate change. The PBLH retrieval from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) is expected to complement ground-based measurements due to the broad spatial coverage of satellites. In this study, CALIOP PBLHs are derived from combination of Haar wavelet and maximum variance techniques, and are further validated against PBLHs estimated from ground-based lidar at Beijing and Jinhua. Correlation coefficients between PBLHs from ground- and satellite-based lidars are 0.59 at Beijing and 0.65 at Jinhua. Also, the PBLH climatology from CALIOP and radiosonde are compiled over China during the period from 2011 to 2014. Maximum CALIOP-derived PBLH can be seen in summer as compared to lower values in other seasons. Three matchup scenarios are proposed according to the position of each radiosonde site relative to its closest CALIPSO ground tracks. For each scenario, intercomparisons were performed between CALIOP- and radiosonde-derived PBLHs, and scenario 2 is found to be better than other scenarios using difference as the criteria. In early summer afternoon over 70 % of the total radiosonde sites have PBLH values ranging from 1.6 to 2.0 km. Overall, CALIOP-derived PBLHs are well consistent with radiosonde-derived PBLHs. To our knowledge, this study is the first intercomparison of PBLH on a large scale using the radiosonde network of China, shedding important light on the data quality of initial CALIOP-derived PBLH results.

Highlights

The planetary boundary layer (PBL), the lowest layer of the troposphere closest to the surface, is directly influenced by the presence of the Earth’s surface and responds to surface forcings on a timescale of about an hour or less (Stull, 1988)
Due to the twice-per-month revisit period of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, only 17 cases out of 24 at Beijing are selected, in which both Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and ground-based lidar have matched up measurements at 13:30 local time (LT)
For the overall comparison between the planetary boundary layer height (PBLH) derived from ground-based lidar and CALIOP, the correlation coefficient through orthogonal regression reaches 0.59 at Beijing and 0.65 at Jinhua

Summary

Introduction

The planetary boundary layer (PBL), the lowest layer of the troposphere closest to the surface, is directly influenced by the presence of the Earth’s surface and responds to surface forcings (e.g., sensible heat flux, mechanical drag) on a timescale of about an hour or less (Stull, 1988). The PBL processes play significant roles in modulating the exchange of momentum, heat, moisture, gases, and aerosols between the Earth’s surface and the free troposphere (Hu et al, 2010, 2014; Miao et al, 2015). A growing consensus has been reached on the role boundary layer processes and structures have played in greatly advancing our capabilities in understanding and predicting weather, climate, and air quality (Medeiros et al, 2005; Hong et al, 2006; Zhang et al, 2007; Hu et al, 2010)

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Results

Conclusion