Characterizing urban planetary boundary layer dynamics using 3-year Doppler wind lidar measurements in a western Yangtze River Delta city, China

<p>The planetary boundary layer (PBL) dynamics play a critical role in shaping urban atmospheric processes by governing the exchange of energy, momentum, and mass within the lower atmosphere. This study investigates PBL dynamics in Hefei, a city in the western Yangtze River Delta (YRD), using...

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Main Authors: T. Wei, M. Wang, K. Wu, J. Yuan, H. Xia, S. Lolli
Format: Article
Language:English
Published: Copernicus Publications 2025-04-01
Series:Atmospheric Measurement Techniques
Online Access:https://amt.copernicus.org/articles/18/1841/2025/amt-18-1841-2025.pdf
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author T. Wei
M. Wang
M. Wang
K. Wu
J. Yuan
H. Xia
H. Xia
S. Lolli
author_facet T. Wei
M. Wang
M. Wang
K. Wu
J. Yuan
H. Xia
H. Xia
S. Lolli
author_sort T. Wei
collection DOAJ
description <p>The planetary boundary layer (PBL) dynamics play a critical role in shaping urban atmospheric processes by governing the exchange of energy, momentum, and mass within the lower atmosphere. This study investigates PBL dynamics in Hefei, a city in the western Yangtze River Delta (YRD), using 3 years (June 2019 to June 2022) of Doppler wind lidar data. Seasonal and diurnal variations in key parameters, including wind profiles, shear intensity, turbulent mixing, low-level jets (LLJs), and mixing layer height (MLH), are analyzed. Results show that horizontal wind speeds accelerate more rapidly above 3 km with the predominant westerly winds (<span class="inline-formula">270<i>°</i>±15<i>°</i></span>) in all seasons. The vertical depth of the high-wind zone (<span class="inline-formula">&gt;8</span> m s<span class="inline-formula"><sup>−1</sup></span>) during the day is found to be generally deeper than at night, particularly in winter. In Hefei, LLJs primarily form at sunset and dissipate by noon, typically at altitudes between 0.5 and 0.6 km throughout the year, except in July. LLJ occurrences are the most frequent in spring (31.7 %), followed by summer (24.7 %), autumn (22.3 %), and winter (21.3 %). Summer LLJs are the most intensified, extending up to 1.5 km. The larger wind gradient below the jets significantly enhances turbulence and shear intensity near the ground at night. The seasonal average MLH peaks between 14:00 and 15:00 UTC+8, reaching approximately 1.2 km in spring and summer. Cloud cover raises MLH by about 100 m at night but decreases it by 200 m at the afternoon peak. This study provides insights into lidar-based PBL dynamics and highlights implications for local standards concerning low-altitude economic activities.</p>
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issn 1867-1381
1867-8548
language English
publishDate 2025-04-01
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series Atmospheric Measurement Techniques
spelling doaj-art-65a6f7ffbdf44b01bbdf6f640d382d742025-08-20T03:15:03ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482025-04-01181841185710.5194/amt-18-1841-2025Characterizing urban planetary boundary layer dynamics using 3-year Doppler wind lidar measurements in a western Yangtze River Delta city, ChinaT. Wei0M. Wang1M. Wang2K. Wu3J. Yuan4H. Xia5H. Xia6S. Lolli7School of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing 210044, ChinaSchool of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing 210044, ChinaChina Meteorological Administration Xiong'an Atmospheric Boundary Layer Key Laboratory, Xiong'an New Area, Baoding 071800, ChinaSchool of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing 210044, ChinaSchool of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing 210044, ChinaSchool of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing 210044, ChinaSchool of Earth and Space Science, University of Science and Technology of China, Hefei 230026, ChinaCNR-IMAA, Contrada S. Loja snc, Tito Scalo (PZ) 85050, Italy<p>The planetary boundary layer (PBL) dynamics play a critical role in shaping urban atmospheric processes by governing the exchange of energy, momentum, and mass within the lower atmosphere. This study investigates PBL dynamics in Hefei, a city in the western Yangtze River Delta (YRD), using 3 years (June 2019 to June 2022) of Doppler wind lidar data. Seasonal and diurnal variations in key parameters, including wind profiles, shear intensity, turbulent mixing, low-level jets (LLJs), and mixing layer height (MLH), are analyzed. Results show that horizontal wind speeds accelerate more rapidly above 3 km with the predominant westerly winds (<span class="inline-formula">270<i>°</i>±15<i>°</i></span>) in all seasons. The vertical depth of the high-wind zone (<span class="inline-formula">&gt;8</span> m s<span class="inline-formula"><sup>−1</sup></span>) during the day is found to be generally deeper than at night, particularly in winter. In Hefei, LLJs primarily form at sunset and dissipate by noon, typically at altitudes between 0.5 and 0.6 km throughout the year, except in July. LLJ occurrences are the most frequent in spring (31.7 %), followed by summer (24.7 %), autumn (22.3 %), and winter (21.3 %). Summer LLJs are the most intensified, extending up to 1.5 km. The larger wind gradient below the jets significantly enhances turbulence and shear intensity near the ground at night. The seasonal average MLH peaks between 14:00 and 15:00 UTC+8, reaching approximately 1.2 km in spring and summer. Cloud cover raises MLH by about 100 m at night but decreases it by 200 m at the afternoon peak. This study provides insights into lidar-based PBL dynamics and highlights implications for local standards concerning low-altitude economic activities.</p>https://amt.copernicus.org/articles/18/1841/2025/amt-18-1841-2025.pdf
spellingShingle T. Wei
M. Wang
M. Wang
K. Wu
J. Yuan
H. Xia
H. Xia
S. Lolli
Characterizing urban planetary boundary layer dynamics using 3-year Doppler wind lidar measurements in a western Yangtze River Delta city, China
Atmospheric Measurement Techniques
title Characterizing urban planetary boundary layer dynamics using 3-year Doppler wind lidar measurements in a western Yangtze River Delta city, China
title_full Characterizing urban planetary boundary layer dynamics using 3-year Doppler wind lidar measurements in a western Yangtze River Delta city, China
title_fullStr Characterizing urban planetary boundary layer dynamics using 3-year Doppler wind lidar measurements in a western Yangtze River Delta city, China
title_full_unstemmed Characterizing urban planetary boundary layer dynamics using 3-year Doppler wind lidar measurements in a western Yangtze River Delta city, China
title_short Characterizing urban planetary boundary layer dynamics using 3-year Doppler wind lidar measurements in a western Yangtze River Delta city, China
title_sort characterizing urban planetary boundary layer dynamics using 3 year doppler wind lidar measurements in a western yangtze river delta city china
url https://amt.copernicus.org/articles/18/1841/2025/amt-18-1841-2025.pdf
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