Analysis of physicochemical characteristics in the atmospheric boundary layer over the North Plain China based on large tethered balloon and Doppler wind lidar

2020 ◽  
Author(s):  
Haijiong Sun ◽  
Yu Shi ◽  
Fei Hu ◽  
Zhe Zhang ◽  
Weichen Ding
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Vertical Profile ◽  
Layer Structure ◽  
Physicochemical Characteristics ◽  
Transport Processes ◽  
Observation Data ◽  
Tethered Balloon ◽  
Wind Lidar ◽  
Doppler Wind Lidar

<p>Physicochemical characteristics of the atmospheric boundary layer over North Plain China during the comprehensive observation experiment from 10 to 21 December 2018 were investigated in this paper. The observation data are obtained from the large tethered balloon, Doppler wind lidar, ground-level instruments. The maximum concentration of PM<sub>2.5</sub> exceeded 200 µg m-3, and the ratio value of PM<sub>2.5</sub>/PM<sub>10</sub> was basically around 0.4 (maximum has reached approximately 0.8) during the whole observation period, indicating that explosive growth of fine ode dominant aerosols during the winter heating season. The peak solar irradiance was slightly larger on the clean day, compared with the value during the pollution process. The correlation coefficient between the concentration of PM<sub>2.5</sub> and CO was highest (0.725) among the gas pollutants, and the relationship between O<sub>3</sub> and PM<sub>2.5</sub> was basically negative correlated, not simple linear relationship. Three distinctly different vertical profile types of the PM<sub>2.5</sub> were categorized according to the vertical changes based on the total 33 vertical profiles obtained by the tethered balloon. Type 1 was mainly observed in the daytime, accounted for nearly 51.5%, the PM<sub>2.5</sub> concentration decreased nearly linearly as a function of height below approximate 600 m; Type 2 shows a sharp decreasing trend from the ground to about 200 m; Type 3 shows multi-layer structure of pollutants, some pollutants suspended aloft in upper air. The vertical profile of PM<sub>2.5</sub> was closely related to the atmospheric vertical structure such as the wind, temperature and turbulent kinetic energy, caused by the diurnal variation of the boundary layer. Small wind layer and the weak turbulence activities contributed to the accumulation of pollutants. Vertical patterns of the concentration of PM<sub>2.5</sub> were also greatly affected by the local ground emission sources and regional transport processes.</p>

scholarly journals Daytime Evolution of Lower Atmospheric Boundary Layer Structure: Comparative Observations between a 307-m Meteorological Tower and a Rotary-Wing UAV

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1142
Author(s):  
Kyung-Hwan Kwak ◽  
Seung-Hyeop Lee ◽  
A-Young Kim ◽  
Kwon-Chan Park ◽  
Sang-Eun Lee ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Relative Humidity ◽  
Atmospheric Boundary Layer ◽  
Layer Structure ◽  
Potential Temperature ◽  
Early Morning ◽  
Observation Data ◽  
Meteorological Tower ◽  
Aerial Vehicle ◽  
Rotary Wing

A 307-m tall meteorological tower was used to evaluate meteorological observation data obtained using a rotary-wing unmanned aerial vehicle (UAV). A comparative study between the tower and UAV observations was conducted during the daytime (06:00 to 19:00 local time (LT)) in the summer of 2017 (16–18th August). Hourly vertical profiles of air temperature, relative humidity, black carbon (BC), and ozone (O3) concentrations were obtained for up to 300 m height. Statistical metrics for evaluating the accuracy of UAV observations against the tower observation showed positive (potential temperature) and negative (relative humidity) biases, which were within acceptable ranges. The daytime evolution of the lower atmospheric boundary layer (ABL) was successfully captured by the hourly UAV observations. During the early morning, a large vertical slope of potential temperature was observed between 100 and 140 m, corresponding to the stable ABL height. The large vertical slope coincided with the large differences in BC and O3 concentrations between altitudes below and above the height. The transition from stable to convective ABL was observed at 10–11 LT, indicated by the ABL height higher than 300 m in the convective ABL. Finally, we provide several recommendations to reduce uncertainties of UAV observation.

scholarly journals Turbulence Detection in the Atmospheric Boundary Layer using Coherent Doppler Wind Lidar and Microwave Radiometer

2021 ◽  
Author(s):  
Pu Jiang ◽  
Jinlong Yuan ◽  
Kenan Wu ◽  
Lu Wang ◽  
Haiyun Xia
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Spatial Resolution ◽  
Microwave Radiometer ◽  
Structure Constant ◽  
New Method ◽  
Index Structure ◽  
Wind Lidar ◽  
Temporal And Spatial ◽  
Doppler Wind Lidar

Abstract. The refractive index structure constant (Cn2) is a key parameter in describing the influence of turbulence on laser transmission in the atmosphere. A new method for continuous Cn2 profiling with both high temporal and spatial resolution is proposed and demonstrated. Under the assumption of the Kolmogorov “2/3 law”, the Cn2 profile can be calculated by using the wind field and turbulent kinetic energy dissipation rate (TKEDR) measured by coherent Doppler wind lidar (CDWL) and other meteorological parameters derived from microwave radiometer (MWR). In the horizontal experiment, a comparison between the results from our new method and measurements made by a large aperture scintillometer (LAS) is conducted. Except for the period of stratification stabilizing, the correlation coefficient between them in the six-day observation is 0.8389, the mean error and standard deviation is 1.09 × 10−15 m−2/3 and 2.14 × 10−15 m−2/3, respectively. In the vertical direction, the continuous observation results of Cn2 and other turbulence parameter profiles in the atmospheric boundary layer (ABL) are retrieved. More details of the atmospheric turbulence can be found in the ABL owe to the high temporal and spatial resolution of MWR and CDWL (spatial resolution of 26 m, temporal resolution of 147 s).

The Relationship Between Atmospheric Boundary Layer Structure, Brown Haze, and Air Pollution in Auckland, New Zealand

2021 ◽  
Author(s):  
Hannah Marley ◽  
Kim Dirks ◽  
Andrew Neverman ◽  
Ian McKendry ◽  
Jennifer Salmond
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
New Zealand ◽  
Atmospheric Boundary Layer ◽  
Boundary Layers ◽  
Layer Structure ◽  
High Surface ◽  
Residual Layer ◽  
Pollution Levels ◽  
Haze Formation

<p><span><span>A brown air pollution haze that forms over some international cities during the winter has been found to be associated with negative health outcomes and high surface air pollution levels. Previous research has demonstrated a well-established link between the structure of the atmospheric boundary layer (ABL) and surface air quality; however, the degree to which the structure of the ABL influences for formation of local-</span></span><span><span>scale</span></span><span><span> brown haze is unknown. Using continuous ceilometer data covering seven consecutive winters, we investigate the influence of the structure of the ABL in relation to surface air pollution and brown haze formation over an urban area of complex coastal terrain in the Southern Hemisphere city of Auckland, New Zealand. Our results suggest the depth and evolution of the ABL has a strong influence on severe brown haze formation. When days with severe brown haze are compared with those when brown haze is expected but not observed (based on favorable meteorology and high surface air pollution levels), days with severe brown haze are found to coincide with significantly shallower daytime convective boundary layers (~ 48% lower), and the nights preceding brown haze formation are found to have significantly shallower nocturnal boundary layers (~ 28% lower). On severe brown haze days the growth rate during the morning transition phase from a nocturnal boundary layer to a convective daytime boundary layer is found to be significantly reduced (70 m h</span></span><sup><span><span>-1</span></span></sup><span><span>) compared to days on which brown haze is expected but not observed (170 m h</span></span><sup><span><span>-1</span></span></sup><span><span>). Compared with moderate brown haze, severe brown haze conditions are found to be associated with a significantly higher proportion of days with a distinct residual layer present in the ceilometer profiles, suggesting the entrainment of residual layer pollutants may contribute to the severity of the haze. This study illustrates the complex interaction between the ABL structure, air pollution, and the presence of brown haze, and demonstrates the utility of a ceilometer instrument in understanding and predicting the occurrence of brown haze events. </span></span></p>

scholarly journals Validation of farm-scale methane emissions using nocturnal boundary layer budgets

2015 ◽  
Vol 15 (15) ◽  
pp. 21765-21802 ◽  
Author(s):  
J. Stieger ◽  
I. Bamberger ◽  
N. Buchmann ◽  
W. Eugster
Keyword(s):  
Boundary Layer ◽  
Nocturnal Boundary Layer ◽  
Methane Emissions ◽  
Emission Factors ◽  
Transport Processes ◽  
Tethered Balloon ◽  
Near Surface ◽  
Time Space ◽  
Farm Scale ◽  
Balloon System

Abstract. This study provides the first experimental validation of Swiss agricultural methane emission estimates at the farm scale. We measured CH4 concentrations at a Swiss farmstead during two intensive field campaigns in August 2011 and July 2012 to (1) quantify the source strength of livestock methane emissions using a tethered balloon system, and (2) to validate inventory emission estimates via nocturnal boundary layer (NBL) budgets. Field measurements were performed at a distance of 150 m from the nearest farm buildings with a tethered balloon system in combination with gradient measurements at eight heights on a 10 m tower to better resolve the near-surface concentrations. Vertical profiles of air temperature, relative humidity, CH4 concentration, wind speed and wind direction showed that the NBL was strongly influenced by local transport processes and by the valley wind system. Methane concentrations showed a pronounced time course, with highest concentrations in the second half of the night. NBL budget flux estimates were obtained via a time–space kriging approach. Main uncertainties of NBL budget flux estimates were associated with instationary atmospheric conditions and the estimate of the inversion height zi (top of volume integration). The mean NBL budget fluxes of 1.60 ± 0.31 μg CH4 m-2 s-1 (1.40 ± 0.50 and 1.66 ± 0.20 μg CH4 m-2 s-1 in 2011 and 2012, respectively) were in good agreement with local inventory estimates based on current livestock number and default emission factors, with 1.29 ± 0.47 and 1.74 ± 0.63 μg CH4 m-2 s-1 for 2011 and 2012, respectively. This indicates that emission factors used for the national inventory reports are adequate, and we conclude that the NBL budget approach is a useful tool to validate emission inventory estimates.

scholarly journals Integrated System for Atmospheric Boundary Layer Height Estimation (ISABLE) using a ceilometer and microwave radiometer

2020 ◽  
Vol 13 (12) ◽  
pp. 6965-6987
Author(s):  
Jae-Sik Min ◽  
Moon-Soo Park ◽  
Jung-Hoon Chae ◽  
Minsoo Kang
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Layer Structure ◽  
Microwave Radiometer ◽  
Accurate Determination ◽  
Integrated System ◽  
Lapse Rate ◽  
High Temporal Resolution ◽  
Near Surface ◽  
Boundary Layer Structure

Abstract. Accurate boundary layer structure and height are critical in the analysis of the features of air pollutants and local circulation. Although surface-based remote sensing instruments provide a high temporal resolution of the boundary layer structure, there are numerous uncertainties in terms of the accurate determination of the atmospheric boundary layer heights (ABLHs). In this study, an algorithm for an integrated system for ABLH estimation (ISABLE) was developed and applied to the vertical profile data obtained using a ceilometer and a microwave radiometer in Seoul city, Korea. A maximum of 19 ABLHs were estimated via the conventional time-variance, gradient, wavelet, and clustering methods using the backscatter coefficient from the ceilometer. Meanwhile, several stable boundary layer heights were extracted through near-surface inversion and environmental lapse rate methods using the potential temperature from the microwave radiometer. The ISABLE algorithm can find an optimal ABLH from post-processing, such as k-means clustering and density-based spatial clustering of applications with noise (DBSCAN) techniques. It was found that the ABLH determined using ISABLE exhibited more significant correlation coefficients and smaller mean bias and root mean square error between the radiosonde-derived ABLHs than those obtained using the most conventional methods. Clear skies exhibited higher daytime ABLH than cloudy skies, and the daily maximum ABLH was recorded in summer because of the more intense radiation. The ABLHs estimated by ISABLE are expected to contribute to the parameterization of vertical diffusion in the atmospheric boundary layer.

Comparison of Atmospheric Boundary Layer Structure Mesured with a Microwave Temperature Profiler and a Mie Scattering Lidar

1996 ◽  
Vol 35 (Part 1, No. 4A) ◽  
pp. 2168-2169
Author(s):  
Ichiro Matsui ◽  
Nobuo Sugimoto ◽  
Shamil Maksyutov ◽  
Gen Inoue ◽  
Evgeny Kadygrov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Layer Structure ◽  
Mie Scattering ◽  
Boundary Layer Structure ◽  
Temperature Profiler
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