Impact of atmospheric boundary layer depth variability and wind reversal on the diurnal variability of aerosol concentration at a valley site

Abstract. The diurnal variation of atmospheric boundary layer (ABL) height is studied using high-resolution radiosonde observations available at 3 h intervals for 3 days continuously from 34 intensive campaigns conducted during the period December 2010–March 2014 over a tropical station Gadanki (13.5° N, 79.2° E; 375 m), in the Indian monsoon region. The heights of the ABL during the different stages of its diurnal evolution, namely, the convective boundary layer (CBL), the stable boundary layer (SBL), and the residual layer (RL) are obtained to study the diurnal variabilities. A clear diurnal variation is observed in 9 campaigns out of the 34 campaigns. In 7 campaigns the SBL did not form in the entire day and in the remaining 18 campaigns the SBL formed intermittently. The SBL forms for 33–55 % of the time during nighttime and 9 and 25 % during the evening and morning hours, respectively. The mean SBL height is within 0.3 km above the surface which increases slightly just after midnight (02:00 IST) and remains almost constant until the morning. The mean CBL height is within 3.0 km above the surface, which generally increases from morning to evening. The mean RL height is within 2 km above the surface which generally decreases slowly as the night progresses. The diurnal variation of the ABL height over the Indian region is stronger during the pre-monsoon and weaker during winter season. The CBL is higher during the summer monsoon and lower during the winter season while the RL is higher during the winter season and lower during the summer season. During all the seasons, the ABL height peaks during the afternoon (∼ 14:00 IST) and remains elevated until evening (∼ 17:00 IST). The ABL suddenly collapses at 20:00 IST and increases slightly in the night. Interestingly, it is found that the low level clouds have an effect on the ABL height variability, but the deep convective clouds do not. The lifting condensation level (LCL) is generally found to occur below the ABL for the majority of the database and they are randomly related.

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Evaluation of modeled atmospheric boundary layer depth at the WLEF tower

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2007.08.012 ◽

2008 ◽

Vol 148 (2) ◽

pp. 206-215 ◽

Cited By ~ 28

Author(s):

A. Scott Denning ◽

Ni Zhang ◽

Chuixiang Yi ◽

Mark Branson ◽

Ken Davis ◽

...

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Layer Depth

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Diurnal variability of the Atmospheric Boundary Layer height over a tropical station in the Indian Monsoon Region

10.5194/acp-2016-542 ◽

2016 ◽

Cited By ~ 1

Author(s):

Sanjay Kumar Mehta ◽

Madineni Venkat Ratnam ◽

Sukumarapillai V. Sunilkumar ◽

Daggumati Narayana Rao ◽

Boddapati V. Krishna Murthy

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Diurnal Variation ◽

Indian Monsoon ◽

Winter Season ◽

Monsoon Region ◽

Diurnal Variability ◽

The Mean ◽

Indian Monsoon Region ◽

Tropical Station

Abstract. The diurnal variation of atmospheric boundary layer (ABL) height is studied using high resolutions radiosonde observations available every 3-h intervals for 3 days continuously from 34 intensive campaigns conducted during the period December 2010–March 2014 over a tropical station Gadanki (13.5° N, 79.2° E), in the Indian monsoon region. The heights of the ABL during the different stages of its diurnal evolution, namely, the convective boundary layer (CBL), the stable boundary layer (SBL), and the residual layer (RL) are obtained to study the diurnal variability. A clear diurnal variability in 9 campaigns is observed while in 7 campaigns the SBL does not form for the entire day and in the remaining 18 campaigns the SBL form intermittently. The SBL forms 33 %–55 % during nighttime and 9 % and 25 % during the evening and morning hours, respectively. The mean SBL height is within 0.3 km above the surface which increases slightly just after midnight (0200 IST) and remain almost steady till morning. The mean CBL height is within 3.0 km above the surface which generally increases from morning to evening. The mean RL height is within 2 km above the surface which generally decreases slowly as the night progresses. Diurnal variation of the ABL height over the Indian region is stronger during the pre-monsoon and weaker during winter season. The CBL is higher during the summer monsoon and lower during the winter season while the RL is higher during winter season and lower during summer season. During all the seasons, the ABL height peaks during the afternoon (~ 1400 IST) and remains elevated till evening (~ 1700 IST). The ABL suddenly collapses at 2000 IST due to cooling after the sunset and increases slightly over night. Interestingly, it is found that the low level clouds have an effect on the ABL height variability, but not the deep convective clouds.

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Investigation of the atmospheric boundary layer depth variability and its impact on the222Rn concentration at a rural site in France

Journal of Geophysical Research Atmospheres ◽

10.1002/2014jd022322 ◽

2015 ◽

Vol 120 (2) ◽

pp. 623-643 ◽

Cited By ~ 30

Author(s):

S. Pal ◽

M. Lopez ◽

M. Schmidt ◽

M. Ramonet ◽

F. Gibert ◽

...

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Rural Site ◽

Layer Depth

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Cluster Analysis: A New Approach Applied to Lidar Measurements for Atmospheric Boundary Layer Height Estimation

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-12-00253.1 ◽

2014 ◽

Vol 31 (2) ◽

pp. 422-436 ◽

Cited By ~ 10

Author(s):

Daniel Toledo ◽

Carmen Córdoba-Jabonero ◽

Manuel Gil-Ojeda

Keyword(s):

Boundary Layer ◽

Cluster Analysis ◽

Statistical Analysis ◽

Atmospheric Boundary Layer ◽

Aerosol Concentration ◽

Boundary Layer Height ◽

Height Determination ◽

Lidar Measurements ◽

Vertical Variations ◽

Basic Features

Abstract Several procedures are widely applied to estimate the atmospheric boundary layer (ABL) top height by using aerosols as tracers from lidar measurements. These methods represent different mathematical approaches, relying on either the abrupt step of the aerosol concentration between the ABL and the free troposphere (FT) or the statistical analysis of vertical variations of the aerosol concentration. An alternative method—the cluster analysis (CA)—has been applied to lidar measurements for the first time, emerging as a useful and robust approach for calculating the ABL height, taking the advantage of both previous variables: the vertical aerosol distribution as obtained from the lidar range-corrected signal (RCS) and the statistical analysis of the RCS profiles in terms of its variance to determine a region of high aerosol loading variability. CA limitations under real situations are also tested, and the effects in ABL height determination of both noise and cloud contamination in RCS are examined. In particular, CA results are weakly sensitive to the signal noise due to the basic features of this statistical method. In addition, differences in the ABL top height, as estimated under cloudy and clear skies, have been found to be lower than 1.8% for a high RCS signal, while no effect is observed for low RCS cloud conditions. Moreover, the CA performance on the ABL top height determination for real cases is also presented, showing the reliable CA skills in reproducing the ABL evolution.

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Investigation of the atmospheric boundary layer dynamics during the ESCOMPTE campaign

Annales Geophysicae ◽

10.5194/angeo-25-597-2007 ◽

2007 ◽

Vol 25 (3) ◽

pp. 597-622 ◽

Cited By ~ 5

Author(s):

F. Saïd ◽

A. Brut ◽

B. Campistron ◽

F. Cousin

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Lower Layer ◽

Lower Troposphere ◽

Sea Breeze ◽

Transport Processes ◽

Topographic Effects ◽

Pollution Transport ◽

Data Set ◽

Diurnal Variability

Abstract. This paper presents some results about the behavior of the atmospheric boundary layer observed during the ESCOMPTE experiment. This campaign, which took place in south-eastern France during summer 2001, was aimed at improving our understanding of pollution episodes in relation to the dynamics of the lower troposphere. Using a large data set, as well as a simulation from the mesoscale non-hydrostatic model Meso-NH, we describe and analyze the atmospheric boundary layer (ABL) development during two specific meteorological conditions of the second Intensive Observation Period (IOP). The first situation (IOP2a, from 22 June to 23 June) corresponds to moderate, dry and cold northerly winds (end of Mistral event), coupled with a sea-breeze in the lower layer, whereas sea-breeze events with weak southerly winds occurred during the second part of the period (IOP2b, from 24 June to 26 June). In this study, we first focus on the validation of the model outputs with a thorough comparison of the Meso-NH simulations with fields measurements on three days of the IOP: 22 June, 23 June and 25 June. We also investigate the structure of the boundary layer on IOP2a when the Mistral is superimposed on a sea breeze. Then, we describe the spatial and diurnal variability of the ABL depths over the ESCOMPTE domain during the whole IOP. This step is essential if one wants to know the depth of the layer where the pollutants can be diluted or accumulated. Eventually, this study intends to describe the ABL variability in relation to local or mesoscale dynamics and/or induced topographic effects, in order to explain pollution transport processes in the low troposphere.

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Turbulence dissipation rate estimated from lidar observations during the LAPSE-RATE field campaign

Earth System Science Data ◽

10.5194/essd-13-3539-2021 ◽

2021 ◽

Vol 13 (7) ◽

pp. 3539-3549

Author(s):

Miguel Sanchez Gomez ◽

Julie K. Lundquist ◽

Petra M. Klein ◽

Tyler M. Bell

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Dissipation Rate ◽

Unmanned Aircraft ◽

Lapse Rate ◽

Diurnal Variability ◽

Field Campaign ◽

University Of Oklahoma ◽

Remotely Piloted Aircraft ◽

The University

Abstract. The International Society for Atmospheric Research using Remotely-piloted Aircraft (ISARRA) hosted a flight week in July 2018 to demonstrate unmanned aircraft systems' (UASs) capabilities in sampling the atmospheric boundary layer. This week-long experiment was called the Lower Atmospheric Profiling Studies at Elevation – a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE) field campaign. Numerous remotely piloted aircraft and ground-based instruments were deployed with the objective of capturing meso- and microscale phenomena in the atmospheric boundary layer. The University of Oklahoma deployed one Halo Streamline lidar, and the University of Colorado Boulder deployed two WindCube lidars. In this paper, we use data collected from these Doppler lidars to estimate turbulence dissipation rate throughout the campaign. We observe large temporal variability of turbulence dissipation close to the surface with the WindCube lidars that is not detected by the Halo Streamline. However, the Halo lidar enables estimating dissipation rate within the whole boundary layer, where a diurnal variability emerges. We also find a higher correspondence in turbulence dissipation between the WindCube lidars, which are not co-located, compared to the Halo and WindCube lidar that are co-located, suggesting a significant influence of measurement volume on the retrieved values of dissipation rate. This dataset has been submitted to Zenodo (Sanchez Gomez and Lundquist, 2020) for free and is openly accessible (https://doi.org/10.5281/zenodo.4399967).

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Evidence of Sea-State Dependence of Aerosol Concentration in the Marine Atmospheric Boundary Layer

Journal of Physical Oceanography ◽

10.1175/jpo-d-16-0058.1 ◽

2017 ◽

Vol 47 (1) ◽

pp. 69-84 ◽

Cited By ~ 9

Author(s):

Luc Lenain ◽

W. Kendall Melville

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Wave Breaking ◽

State Dependence ◽

Aerosol Concentration ◽

Sea Spray ◽

Marine Atmospheric Boundary Layer ◽

Sea State ◽

Wave Parameters ◽

Interaction Experiment

AbstractSea spray aerosols represent a large fraction of the aerosols present in the maritime environment. Despite evidence of the importance of surface wave– and wave breaking–related processes in coupling the ocean with the atmosphere, sea spray source generation functions are traditionally parameterized by the 10-m wind speed U10 alone. It is clear that unless the wind and wave field are fully developed, the source function will be a function of both wind and wave parameters. This study reports primarily on the aerosol component of an air–sea interaction experiment, the phased-resolved High-Resolution Air–Sea Interaction Experiment (HIRES), conducted off the coast of northern California in June 2010. Detailed measurements of aerosol number concentration in the marine atmospheric boundary layer (MABL) at altitudes ranging from as low as 30 m up to 800 m above mean sea level (MSL) over a broad range of environmental conditions (significant wave height Hs of 2 to 4.5 m and U10 from 10 to 18 m s−1) collected from an instrumented research aircraft are presented. Aerosol number densities and volume are computed over a range of particle diameters from 0.1 to 200 μm, while the sea surface conditions, including Hs, moments of the breaker length distribution Λ(c), and wave breaking dissipation, were measured by a suite of electro-optical sensors that included the NASA Airborne Topographic Mapper (ATM). The sea-state dependence of the aerosol concentration in the MABL is evident, stressing the need to incorporate wave parameters in the spray source generation functions that are traditionally parameterized by surface winds alone.

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