Determination of atmospheric nitrate particulate size distribution and dry deposition velocity for three distinct areas

Abstract. The possible minimal range of reduction in snow surface albedo due to dry deposition of black carbon (BC) in the pre-monsoon period (March–May) was estimated as a lower bound together with the estimation of its accuracy, based on atmospheric observations at the Nepal Climate Observatory-Pyramid (NCO-P) sited at 5079 m a.s.l. in the Himalayan region. We estimated a total BC deposition rate of 2.89 μg m−2 day−1 providing a total deposition of 266 μg m−2 for March–May at the site, based on a calculation with a minimal deposition velocity of 1.0×10−4 m s−1 with atmospheric data of equivalent BC concentration. Main BC size at NCO-P site was determined as 103.1–669.8 nm by correlation analysis between equivalent BC concentration and particulate size distribution in the atmosphere. We also estimated BC deposition from the size distribution data and found that 8.7% of the estimated dry deposition corresponds to the estimated BC deposition from equivalent BC concentration data. If all the BC is deposited uniformly on the top 2-cm pure snow, the corresponding BC concentration is 26.0–68.2 μg kg−1 assuming snow density variations of 195–512 kg m−3 of Yala Glacier close to NCO-P site. Such a concentration of BC in snow could result in 2.0–5.2% albedo reductions. From a simple numerical calculations and if assuming these albedo reductions continue throughout the year, this would lead to a runoff increases of 70–204 mm of water drainage equivalent of 11.6–33.9% of the annual discharge of a typical Tibetan glacier. Our estimates of BC concentration in snow surface for pre-monsoon season can be considered comparable to those at similar altitude in the Himalayan region, where glaciers and perpetual snow region starts in the vicinity of NCO-P. Our estimates from only BC are likely to represent a lower bound for snow albedo reductions, since a fixed slower deposition velocity was used and atmospheric wind and turbulence effects, snow aging, dust deposition, and snow albedo feedbacks were not considered. This study represents the first investigation about BC deposition on snow from atmospheric aerosol data in Himalayas and related albedo effect is especially the first track at the southern slope of Himalayas.

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Vertical Flux Measurements of the Submicronic Aerosol Particles and Parametrisation of the Dry Deposition Velocity

Biosphere-Atmosphere Exchange of Pollutants and Trace Substances ◽

10.1007/978-3-662-03394-4_30 ◽

1997 ◽

pp. 381-390 ◽

Cited By ~ 3

Author(s):

J. Fontan ◽

A. Lopez ◽

E. Lamaud ◽

A. Druilhet

Keyword(s):

Dry Deposition ◽

Aerosol Particles ◽

Deposition Velocity ◽

Vertical Flux ◽

Dry Deposition Velocity ◽

Flux Measurements

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Determining PM2.5 dry deposition velocity on plant leaves: An indirect experimental method

Urban Forestry & Urban Greening ◽

10.1016/j.ufug.2019.126467 ◽

2019 ◽

Vol 46 ◽

pp. 126467 ◽

Cited By ~ 2

Author(s):

Shan Yin ◽

Xuyi Zhang ◽

Annie Yu ◽

Ningxiao Sun ◽

Junyao Lyu ◽

...

Keyword(s):

Experimental Method ◽

Dry Deposition ◽

Deposition Velocity ◽

Plant Leaves ◽

Dry Deposition Velocity

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Profile measurements of particle dry deposition velocity at an air-land interface

Atmospheric Environment (1967) ◽

10.1016/0004-6981(82)90446-2 ◽

1982 ◽

Vol 16 (2) ◽

pp. 301-306 ◽

Cited By ~ 50

Author(s):

Herman Sievering

Keyword(s):

Dry Deposition ◽

Deposition Velocity ◽

Dry Deposition Velocity

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Aerosol dry deposition measured with eddy-covariance technique at Wasa and Aboa, DronningMaud Land, Antarctica

Annals of Glaciology ◽

10.3189/172756402781816519 ◽

2002 ◽

Vol 35 ◽

pp. 355-361 ◽

Cited By ~ 23

Author(s):

Anna Grönlund ◽

Douglas Nilsson ◽

Ismo K. Koponen ◽

Aki Virkkula ◽

Margareta E. Hansson

Keyword(s):

Eddy Covariance ◽

Dry Deposition ◽

Transfer Functions ◽

Deposition Velocity ◽

Ice Core ◽

Brownian Diffusion ◽

Wind Component ◽

Surface Boundary ◽

Surface Boundary Layer ◽

Dry Deposition Velocity

AbstractInterpretation of ice-core records in terms of changes in atmospheric concentrations requires understanding of the various parameters within air–snow transfer functions. the dry-deposition velocity is one of these parameters, dependent on local meteorological conditions and thereby also affected by climate changes. We have determined aerosol dry-deposition velocities by measurements of aerosol particle-number concentration and the vertical wind component with an eddy-covariance system close to the Swedish and Finnish research stations Wasa and Aboa in Dronning Maud Land, Antarctica. Measurements were performed over a smooth, snow-covered area and over moderately rough, rocky ground during 4 and 19 days, respectively, in January 2000. the median dry-deposition velocity determined 5.25 mabove the surface was 0.33 and 0.80 cm s–1, respectively. the large difference between the two sites was mainly due to the stratification of the surface boundary layer, the surface albedo and the surface roughness height. the dry-deposition number fluxes were dominated by the particle-size modes defined as ultrafine and Aitken, withmean diameters around 14 and 42 nm, respectively. A larger dry-deposition velocity, owing to stronger Brownian diffusion, for the smaller ultrafine mode was verified by the measurements.

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