Influence of chemical aging on physico-chemical properties of mineral dust particles: A case study of 2016 dust storms over Delhi

Goel, Vikas; Mishra, Sumit; Pal, Prabir; Ahlawat, Ajit; Jain, Srishti; Sharma, C.

doi:10.1016/j.envpol.2020.115338

Cited by 24 publications

(11 citation statements)

References 51 publications

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“…The aerosol type identified by CALIPSO for dust-dominated cases is mostly dusty marine (dust + marine) and not pure dust. Under such situations where the dust particles are far away from their source regions, their microphysical properties may change because of either ageing or chemical or cloud processing (Kim and Park, 2012;Ansmann et al, 2019;Goel et al, 2020). Also, three-quarters of the CALIPSO retrieval for dust-dominated cases are daytime retrievals.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of aerosol number concentrations from CALIPSO with ATom airborne in situ measurements

2022

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Abstract. The present study aims to evaluate the available aerosol number concentration (ANC) retrieval algorithms for spaceborne lidar CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) aboard the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) satellite with the airborne in situ measurements from the ATom (Atmospheric Tomography Mission) campaign. We used HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory model) to match both the measurements in space and identified 53 cases that were suitable for comparison. Since the ATom data include the dry aerosol extinction coefficient, we used kappa parameterization to adjust the ambient measurements from CALIOP to dry conditions. As both the datasets have a different vertical resolution, we regrid them to uniform height bins of 240 m from the surface to a height of 5 km. On comparing the dry extinction coefficients, we found a reasonable agreement between the CALIOP and ATom measurements with Spearman's correlation coefficient of 0.715. Disagreement was found mostly for retrievals above 3 km altitude. Thus, to compare the ANC, which may vary by orders of magnitude in space and time, we further limit the datasets and only select those height bins for which the CALIOP-derived dry extinction coefficient is within ±50 % of the ATom measurements. This additional filter further increases the probability of comparing the same air parcel. The altitude bins which qualify the extinction coefficient constraint are used to estimate ANC with a dry radius >50 nm (n50,dry) and >250 nm (n250,dry). The POLIPHON (Polarization Lidar Photometer Networking) and OMCAM (Optical Modelling of CALIPSO Aerosol Microphysics) algorithms were used to estimate the n50,dry and n250,dry. The POLIPHON estimates of n50,dry and n250,dry were found to be in good agreement with the in situ measurements, with a correlation coefficient of 0.829 and 0.47, root mean square error (RMSE) of 234 and 13 cm−3, and bias of −97 and 4 cm−3, respectively. The OMCAM estimates of n50,dry and n250,dry were also in reasonable agreement with the in situ measurements, with a correlation coefficient of 0.823 and 0.463, RMSE of 247 and 13 cm−3, and bias of 44 and 4 cm−3, respectively. However, we found that the OMCAM-estimated n50,dry were about an order of magnitude less than the in situ measurements for marine-dominated cases. We propose a modification to the OMCAM algorithm by using an AERONET-based marine model. With the updated OMCAM algorithm, the n50,dry agrees well with the ATom measurements. Such concurrence between the satellite-derived ANC and the independent ATom in situ measurements emboldens the use of CALIOP in studying the aerosol–cloud interactions.

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Section: Discussionmentioning

confidence: 99%

Evaluation of aerosol number concentrations from CALIPSO with ATom airborne in situ measurements

2022

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“…The potential source regions contributing to the BC concentration at the receptor site were identified with the help of the Concentration Weighted Trajectories (CWT) analysis ( Goel et al., 2020 ; Jain et al., 2017 ). Potential source regions surrounding the receptor site were divided into ij th gridded array.…”

Section: Methodsmentioning

confidence: 99%

“…Black Carbon (BC) strongly absorbs solar radiation and causes positive radiative forcing due to the high value of the imaginary part of its refractive index ( Bond et al., 2013 ; Goel et al., 2020 ). It affects the Earth’s radiation budget through direct, semidirect, and indirect effects.…”

Section: Introductionmentioning

confidence: 99%

Variations in Black Carbon concentration and sources during COVID-19 lockdown in Delhi

et al. 2021

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A nationwide lockdown was imposed in India due to COVID-19 pandemic in five phases from 25th March to May 31, 2020. The lockdown restricted major anthropogenic activities, primarily vehicular and industrial, thereby reducing the particulate matter concentration. This work investigates the variation in Black Carbon (BC) concentration and its sources (primarily Fossil Fuel (ff) burning and Biomass Burning (bb)) over Delhi from 18th February to July 31, 2020, covering one month of pre-lockdown phase, all the lockdown phases, and two months of successive lockdown relaxations. The daily average BC concentration varied from 0.22 to 16.92 μg/m 3 , with a mean value of 3.62 ± 2.93 μg/m 3 . During Pre-Lockdown (PL, 18th Feb-24th March 2020), Lockdown-1 (L1, 25th March-14th April 2020), Lockdown-2 (L2, 15th April-3rd May 2020), Lockdown-3 (L3, 4th-17th May 2020), Lockdown-4 (L4, 18th-31st May 2020), Unlock-1 (UN1, June 2020), and Unlock-2 (UN2, July 2020) the average BC concentrations were 7.93, 1.73, 2.59, 3.76, 3.26, 2.07, and 2.70 μg/m 3 , respectively. During the lockdown and unlock phases, BC decreased up to 78% compared to the PL period. The BC source apportionment studies show that fossil fuel burning was the dominant BC source during the entire sampling period. From L1 to UN2 an increasing trend in BC ff contribution was observed (except L3) due to the successive relaxations given to anthropogenic activities. BC ff contribution dipped briefly during L3 due to the intensive crop residue burning events in neighboring states. CWT analysis showed that local emission sources were the dominant contributors to BC concentration over Delhi.

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“…The 48 h backward trajectories at hourly intervals were plotted at an altitude of 50 m throughout the observation period. The concentration-weighted trajectory (CWT) analysis method is based on the identification of potential sources of BC and the weighted average of trajectories of relevant concentrations to identify the contribution of potential source regions to BC [53,54]. CWT was calculated with ZeFir, a programming plug-in based on Igor Pro (Wavemetrics, USA).…”

Section: Air Mass Back-trajectory Analysismentioning

confidence: 99%

One-Year Real-Time Measurement of Black Carbon in the Rural Area of Qingdao, Northeastern China: Seasonal Variations, Meteorological Effects, and the COVID-19 Case Analysis

et al. 2021

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In this paper, we report the results obtained from one year of real-time measurement (i.e., from December 2019 to November 2020) of atmospheric black carbon (BC) under a rural environment in Qingdao of Northeastern China. The annual average concentration of BC was 1.92 ± 1.89 μg m−3. The highest average concentration of BC was observed in winter (3.65 ± 2.66 μg m−3), followed by fall (1.73 ± 1.33 μg m−3), spring (1.53 ± 1.33 μg m−3), and summer (0.83 ± 0.56 μg m−3). A clear weekend effect was observed in winter, which was characterized by higher BC concentration (4.60 ± 2.86 μg m−3) during the weekend rather than that (3.22 ± 2.45 μg m−3) during weekdays. The influence of meteorological parameters, including surface horizontal wind speed, boundary layer height (BLH), and precipitation, on BC, was investigated. In particular, such BLH influence presented evidently seasonal dependence, while there was no significant seasonality for horizontal wind speed. These may reflect different roles of atmospheric vertical dilution on affecting BC in different seasons. The △BC/△CO ratio decreased with the increase of precipitation, indicative of the influence of below-cloud wet removal of BC, especially during summertime where rainfall events more frequently occurred than any of other seasons. The bivariate-polar-plot analysis showed that the high BC concentrations were mainly associated with low wind speed in all seasons, highlighting an important BC source originated from local emissions. By using concentration-weighted trajectory analysis, it was found that regional transports, especially from northeastern in winter, could not be negligible for contributing to BC pollution in rural Qingdao. In the coronavirus disease 2019 (COVID−19) case analysis, we observed an obvious increase in the BC/NO2 ratio during the COVID-19 lockdown, supporting the significant non-traffic source sector (such as residential coal combustion) for BC in rural Qingdao.

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Influence of chemical aging on physico-chemical properties of mineral dust particles: A case study of 2016 dust storms over Delhi

Cited by 24 publications

References 51 publications

Evaluation of aerosol number concentrations from CALIPSO with ATom airborne in situ measurements

Evaluation of aerosol number concentrations from CALIPSO with ATom airborne in situ measurements

Variations in Black Carbon concentration and sources during COVID-19 lockdown in Delhi

One-Year Real-Time Measurement of Black Carbon in the Rural Area of Qingdao, Northeastern China: Seasonal Variations, Meteorological Effects, and the COVID-19 Case Analysis

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