Using a coupled LES aerosol–radiation model to investigate the importance of aerosol–boundary layer feedback in a Beijing haze episode

2021 ◽  
Author(s):  
Jessica Slater ◽  
Juha Tonttila ◽  
Gordon McFiggans ◽  
Hugh Coe ◽  
Sami Romakkaniemi ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Urban Environment ◽  
Radiation Model ◽  
Haze Episode

In this study we use a coupled LES aerosol–radiation model (UCLALES-SALSA), which we have recently configured for the urban environment of Beijing.

Variations in CO, O3 and black carbon aerosol mass concentrations associated with planetary boundary layer (PBL) over tropical urban environment in India

2009 ◽  
Vol 62 (1) ◽  
pp. 73-86 ◽  
Author(s):  
K. V. S. Badarinath ◽  
Anu Rani Sharma ◽  
Shailesh Kumar Kharol ◽  
V. Krishna Prasad
Keyword(s):  
Boundary Layer ◽  
Urban Environment ◽  
Black Carbon ◽  
Planetary Boundary Layer ◽  
Aerosol Mass ◽  
Black Carbon Aerosol ◽  
Mass Concentrations

Experimental investigation of variations in morphology, composition and mixing-state of boundary layer aerosol: A balloon based study over urban environment (New Delhi)

2018 ◽  
Vol 185 ◽  
pp. 243-252 ◽  
Author(s):  
S.K. Mishra ◽  
A. Ahlawat ◽  
D. Khosla ◽  
C. Sharma ◽  
M.V.S.N. Prasad ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Urban Environment ◽  
New Delhi ◽  
Mixing State

Evaluation of boundary-layer and urban-canopy parameterizations for simulating wind in Miami during Hurricane Irma (2017)

2021 ◽  
Author(s):  
Eric A. Hendricks ◽  
Jason C. Knievel ◽  
David S. Nolan
Keyword(s):  
Boundary Layer ◽  
Urban Environment ◽  
Weather Prediction ◽  
Urban Canopy ◽  
Surface Velocity ◽  
Urban Region ◽  
Near Surface ◽  
Model Simulations ◽  
Closure Scheme ◽  
Hurricane Irma

AbstractThe simulated winds within the urban canopy of landfalling tropical cyclones are sensitive to the representation of the planetary-boundary and urban-canopy layers in numerical weather prediction models. In order to assess the sub-grid-scale parameterizations of these layers, mesoscale model simulations were executed and evaluated against near-surface observations as the outer wind field of Hurricane Irma (2017) interacted with the built-up region from downtown Miami northward to West Palm Beach. Four model simulations were examined, comprised of two different planetary boundary layer (PBL) parameterizations (a local closure scheme with turbulent kinetic energy prediction and a nonlocal closure scheme) and two different urban canopy models (UCMs) [a zeroth order bulk scheme and a multilayer Building Effect Parameterization (BEP) that mimics the three-dimensionality of buildings]. Overall, the simulated urban canopy winds were weakly sensitive to the PBL scheme and strongly sensitive to the UCM. The bulk simulations compared most favorably to an analyzed wind swath in the urban environment, while the BEP simulations had larger negative biases in the same region. There is uncertainty in magnitude of the urban environment biases due to the lack of many urban sheltered measurements in the wind swath analysis. Biases in the rural environment were similar among the bulk and BEP simulations. An improved comparison with the analyzed wind swath in the urban region was obtained by reducing the drag coefficient in BEP in one of the PBL schemes. The usefulness of BEP was demonstrated in its ability to predict realistic heterogeneous near-surface velocity patterns in urban regions.

scholarly journals Determination of the Atmospheric Boundary-Layer within the Urban Environment

2006 ◽  
Vol 49 (3) ◽  
pp. 556-566
Author(s):  
Lionel ELLIOTT ◽  
Derek Binns INGHAM ◽  
Stephen David WRIGHT
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Urban Environment

scholarly journals Rapid formation of intense haze episode in Beijing

2018 ◽  
Author(s):  
Yonghong Wang ◽  
Yuesi Wang ◽  
Guiqian Tang ◽  
Tao Song ◽  
Putian Zhou ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
Particulate Matter ◽  
Kinetic Energy ◽  
Air Pollutants ◽  
Mixing Layer ◽  
Feedback Mechanism ◽  
Quality Models ◽  
Rapid Formation ◽  
Haze Episode

Abstract. Although much efforts have been put on studying air pollution, our knowledge on the mechanisms of frequently occurred intense haze episodes in China is still limited. In this study, using three years of measurements of air pollutants at three different height levels on a 325-meter Beijing meteorology tower, we found that a positive particulate matter-boundary layer feedback mechanism existed at three vertical observation heights during intense haze polluted periods within the mixing layer. This feedback was characterized by a higher loading of PM2.5 with a shallower mixing layer. Measurements showed that the feedback was related to the decrease of solar radiation, turbulent kinetic energy and thereby suppression of the mixing layer. The feedback mechanism can explain the rapid formation of intense haze episodes to some extent, and we suggest that the feedback mechanism should be considered in air quality models for better predictions.

scholarly journals High resolution vertical distribution and sources of HONO and NO<sub>2</sub> in the nocturnal boundary layer in urban Beijing, China

2019 ◽  
Author(s):  
Fanhao Meng ◽  
Min Qin ◽  
Ke Tang ◽  
Jun Duan ◽  
Wu Fang ◽  
...  
Keyword(s):  
Boundary Layer ◽  
High Resolution ◽  
Vertical Distribution ◽  
Heterogeneous Reaction ◽  
Ground Surface ◽  
Ground Level ◽  
Urban Atmosphere ◽  
Surface Measurement ◽  
Enhanced Absorption ◽  
Haze Episode

Abstract. The production of HONO on aerosol surfaces and ground surfaces in urban atmosphere is of interests. However, ground surface measurement commonly in our society is not able to distinguish these two parts. Here, for the first time, we reported high-resolution vertical profile measurements of HONO and NO2 in urban Beijing at night using an incoherent broadband cavity enhanced absorption spectrometer (IBBCEAS) amounted on a movable container which attached to a meteorological tower of 325 m high. The mixing ratios of HONO during one haze episode (E1), the clean episode (C2) and another haze episode (E3) were 4.26 ± 2.08, 0.83 ± 0.65, and 3.54 ± 0.91 ppb, respectively. High-resolution vertical profiles revealed that the vertical distribution of HONO is consistent with stratification and layering in the nocturnal urban atmosphere below 250 m. Direct emissions from combustion processes contributed 51.1 % to ambient HONO concentration at night. The HONO production from the heterogeneous conversion of NO2 on the aerosol surfaces cannot explain HONO vertical measurements at night, indicating that the heterogeneous reaction of NO2 on ground surfaces dominated the nocturnal HONO production. The nocturnal HONO in the boundary layer is primarily derived from the heterogeneous conversion of NO2 at ground level and direct emissions; it is then transported throughout the column by vertical convection. ϕNO2 → HONO, the HONO yield from deposited NO2, is used to evaluate HONO production from the heterogeneous conversion of NO2 at night. The derived ϕNO2 → HONO values on 9 (C2), 10 (C2) and 11 December (E3) were 0.10, 0.08, and 0.09, respectively, indicating a significant production of HONO from heterogeneous reaction of NO2 at ground level. The similar ϕNO2 → HONO values measured during clean and haze episodes suggest that the heterogeneous conversion potential of NO2 at ground level is consistent at night. Furthermore, the dry deposition loss of HONO to the ground surface and vertical mixing effects associated with convection reached a near steady state at midnight on 11–12 December, indicating that significant quantities of HONO are deposited to the ground surface at night, and the ground surface is the source and sink of HONO at night.

scholarly journals Rapid formation of intense haze episodes via aerosol–boundary layer feedback in Beijing

2020 ◽  
Vol 20 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Yonghong Wang ◽  
Miao Yu ◽  
Yuesi Wang ◽  
Guiqian Tang ◽  
Tao Song ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollutants ◽  
Mixing Layer ◽  
Feedback Mechanism ◽  
Field Observations ◽  
Layer Height ◽  
Rapid Formation ◽  
Mixing Layer Height ◽  
Haze Episode ◽  
Reduced Surface

Abstract. Although much effort has been put into studying air pollution, our knowledge of the mechanisms of frequently occurring intense haze episodes in China is still limited. In this study, using 3 years of measurements of air pollutants at three different height levels on a 325 m Beijing meteorology tower, we found that a positive aerosol–boundary layer feedback mechanism existed at three vertical observation heights during intense haze polluted periods within the mixing layer. This feedback was characterized by a higher loading of PM2.5 with a shallower mixing layer. Modelling results indicated that the presence of PM2.5 within the boundary layer led to reduced surface temperature, relative humidity and mixing layer height during an intensive haze episode. Measurements showed that the aerosol–boundary layer feedback was related to the decrease in solar radiation, turbulent kinetic energy and thereby suppression of the mixing layer. The feedback mechanism can explain the rapid formation of intense haze episodes to some extent, and we suggest that the detailed feedback mechanism warrants further investigation from both model simulations and field observations.

scholarly journals Comparison of four different types of planetary boundary layer heights during a haze episode in Beijing

2020 ◽  
Vol 711 ◽  
pp. 134928 ◽  
Author(s):  
Yu Shi ◽  
Fei Hu ◽  
Zhisheng Xiao ◽  
Guangqiang Fan ◽  
Zhe Zhang
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Different Types ◽  
Haze Episode

scholarly journals The effect of black carbon on aerosol-boundary layer feedback: Potential implications for Beijing haze episodes

2021 ◽  
Author(s):  
Jessica Slater ◽  
Hugh Coe ◽  
Gordon McFiggans ◽  
Juha Tonttila ◽  
Sami Romakkaniemi
Keyword(s):  
Boundary Layer ◽  
High Resolution ◽  
Black Carbon ◽  
Lower Atmosphere ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Resolution Model ◽  
Haze Episode ◽  
High Resolution Model ◽  
The Impact

Abstract. Beijing suffers from poor air quality particularly during wintertime haze episodes when concentrations of PM2.5 can peak at > 400 ug/m3. Black carbon (BC), an aerosol which strongly absorbs solar radiation can make up to 10 % of PM2.5 in Beijing. Black carbon is of interest due to its climatic and health impacts. Black carbon has also been found to impact planetary boundary layer (PBL) meteorology. Through interacting with radiation and altering the thermal profile of the lower atmosphere, BC can either suppress or enhance PBL development to various degrees depending on the properties and altitude of the BC layer.Previous research assessing the impact of BC on PBL meteorology has been investigated through the use of regional models which are limited both by resolution and the chosen boundary layer schemes. In this work, we apply a high resolution coupled large eddy simulation-aerosol-radiation model (UCLALES-SALSA) to quantify the impact of black carbon at different altitudes on PBL dynamics using conditions from a specific haze episode which occurred from 1st–4th Dec 2016 in Beijing. Results presented in this paper quantify the heating rate of BC at various altitudes to be between 0.01 and 0.016 K/h per μg/m3 of BC, increasing with altitude but decreasing across the PBL. Through utilising a high resolution model which explicitly calculates turbulent dynamics, this paper showcases the impact of BC on PBL dynamics both within and above the PBL. These results show that BC within the PBL increases maximum PBL height by 0.4 % but that the same loading of BC above the PBL can suppress PBL height by 6.5 %. Furthermore, when BC is present throughout the column the impact of BC suppressing PBL development is further maximised, with BC causing a 17 % decrease in maximum PBL height compared to only scattering aerosols. Combining these results in this paper, we present a mechanism through which BC may play a prominent role in the intensity and longevity of Beijing’s pollution episodes.

Sign in / Sign up

Export Citation Format

Share Document