Atmospheric boundary layer top height in South Africa: measurements with lidar and radiosonde compared to three atmospheric models
Kimmo Korhonen,Kimmo Korhonen,E. Giannakaki,Tero Mielonen,A. Pfüller,Lauri Laakso,Lauri Laakso,Ville Vakkari,Ville Vakkari,Holger Baars,Ronny Engelmann,Johan P. Beukes,P. G. van Zyl,Avishkar Ramandh,L. Ntsangwane,Miroslav Josipovic,Petri Tiitta,Petri Tiitta,Gerhardus D. Fourie,I. Ngwana,K. Chiloane,Mika Komppula +21 more
TLDR
In this paper, a long-term study of PBL top heights and PBL growth rates in South Africa was conducted using ground-based and satellite LIDAR measurements, and the results indicated that the ECMWF model agreed the best with mean relative difference of 15.4%, while the second best correlation was with the SAWS model with corresponding difference of 20.1%.Abstract:
. Atmospheric lidar measurements were carried out at Elandsfontein measurement station, on the eastern Highveld approximately 150 km east of Johannesburg in South Africa throughout 2010. The height of the planetary boundary layer (PBL) top was continuously measured using a Raman lidar, PollyXT (POrtabLe Lidar sYstem eXTended). High atmospheric variability together with a large surface temperature range and significant seasonal changes in precipitation were observed, which had an impact on the vertical mixing of particulate matter, and hence, on the PBL evolution. The results were compared to radiosondes, CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) space-borne lidar measurements and three atmospheric models that followed different approaches to determine the PBL top height. These models included two weather forecast models operated by ECMWF (European Centre for Medium-range Weather Forecasts) and SAWS (South African Weather Service), and one mesoscale prognostic meteorological and air pollution regulatory model TAPM (The Air Pollution Model). The ground-based lidar used in this study was operational for 4935 h during 2010 (49% of the time). The PBL top height was detected 86% of the total measurement time (42% of the total time). Large seasonal and diurnal variations were observed between the different methods utilised. High variation was found when lidar measurements were compared to radiosonde measurements. This could be partially due to the distance between the lidar measurements and the radiosondes, which were 120 km apart. Comparison of lidar measurements to the models indicated that the ECMWF model agreed the best with mean relative difference of 15.4%, while the second best correlation was with the SAWS model with corresponding difference of 20.1%. TAPM was found to have a tendency to underestimate the PBL top height. The wind speeds in the SAWS and TAPM models were strongly underestimated which probably led to underestimation of the vertical wind and turbulence and thus underestimation of the PBL top height. Comparison between ground-based and satellite lidar shows good agreement with a correlation coefficient of 0.88. On average, the daily maximum PBL top height in October (spring) and June (winter) was 2260 m and 1480 m, respectively. To our knowledge, this study is the first long-term study of PBL top heights and PBL growth rates in South Africa.read more
Citations
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An overview of the first decade of Polly NET : an emerging network of automated Raman-polarization lidars for continuous aerosol profiling
Holger Baars,Thomas Kanitz,Thomas Kanitz,Ronny Engelmann,Dietrich Althausen,Birgit Heese,Mika Komppula,Jana Preißler,Matthias Tesche,Matthias Tesche,Albert Ansmann,Ulla Wandinger,Jae-Hyun Lim,Joon Young Ahn,Iwona S. Stachlewska,Vassilis Amiridis,Eleni Marinou,Patric Seifert,Julian Hofer,Annett Skupin,Florian Schneider,Stephanie Bohlmann,Andreas Foth,Andreas Foth,Sebastian Bley,A. Pfüller,Eleni Giannakaki,Heikki Lihavainen,Yrjö Viisanen,Rakesh K. Hooda,Rakesh K. Hooda,Sergio Pereira,Daniele Bortoli,Frank Wagner,Ina Mattis,Lucja Janicka,Krzysztof M. Markowicz,Peggy Achtert,Peggy Achtert,Paulo Artaxo,Theotonio Pauliquevis,Rodrigo Augusto Ferreira de Souza,Ved Prakesh Sharma,Pieter G. van Zyl,Johan P. Beukes,Junying Sun,Erich G. Rohwer,Ruru Deng,Rodanthi-Elisavet Mamouri,Felix Zamorano +49 more
TL;DR: PollyNET as mentioned in this paper consists of portable, remote-controlled multiwavelength-polarization-Raman lidars (Polly) for automated and continuous 24/7 observations of clouds and aerosols.
Journal ArticleDOI
Puzzling haze events in China during the coronavirus (COVID-19) shutdown.
Yunhua Chang,Ru-Jin Huang,Xinlei Ge,Xiangpeng Huang,Jianlin Hu,Yusen Duan,Zhong Zou,Xuejun Liu,Moritz F. Lehmann +8 more
TL;DR: During NYH‐20, PM2.5 levels correlated significantly with the oxidation ratio of nitrogen, and aged particles from northern China were found to impede atmospheric new particle formation and growth in Shanghai.
Journal ArticleDOI
Mixing-layer height retrieval with ceilometer and Doppler lidar: from case studies to long-term assessment
TL;DR: In this paper, a case study reveals difficulties in the aerosol-based MLH retrieval during transition times when the mixing layer builds up in the morning and when turbulence decays in the afternoon.
Journal ArticleDOI
Planetary boundary layer height from CALIOP compared to radiosonde overChina
TL;DR: In this paper, the authors derived a planetary boundary layer height (PBLH) from a combination of Haar wavelet and maximum variance techniques, and further validated it with ground-based lidar at Beijing and Jinhua.
Posted ContentDOI
Investigation of near-global daytime boundary layer height using high-resolution radiosondes: first results and comparison with ERA5, MERRA-2, JRA-55, and NCEP-2 reanalyses
Jianping Guo,Jian Zhang,Kun Yang,Hong Liao,Shaodong Zhang,Kaiming Huang,Yanmin Lv,Jia Shao,Tao Yu,Bing Tong,Jian Li,Tianning Su,Steve Hung Lam Yim,Ad Stoffelen,Panmao Zhai,Xiaofeng Xu +15 more
TL;DR: In this article, the authors presented a near-global view of high-resolution radiosonde-derived boundary layer height and provided a quantitative assessment of the four frequently used reanalysis products, ERA5, MERRA-2, JRA-55, and NCEP-2.
References
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