Unexpected high levels of NO observed at South Pole

Davis, Douglas D.; Nowak, John B.; Chen, G.; Buhr, M. P.; Arimoto, R.; Hogan, Austin W.; Eisele, F.; Mauldin, L.; Tanner, David J.; Shetter, R. E.; Lefer, B. L.; McMurry, Peter H.

doi:10.1029/2000gl012584

Cited by 201 publications

(206 citation statements)

References 20 publications

(5 reference statements)

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“…This daily cycle atop the East Antarctic ice sheet was attributed to: (i) an intense oxidation of Hg(0) in the atmospheric boundary layer due to the high level of oxidants present there (Davis et al, 2001;Grannas et al, 2007;Eisele et al, 2008;Kukui et al, 2014), (ii) Hg(II) dry deposition onto the snowpack, and (iii) increased emission of Hg(0) from the snowpack around midday as a response to daytime heating following photoreduction of Hg(II) in the upper layers of the snowpack. Even if DDU is located on snow free bedrock for most of the summer season, the same mechanism could apply since the station is surrounded by vast snow-covered areas.…”

Section: (A) Role Of Penguin Emissionsmentioning

confidence: 99%

Multi-year record of atmospheric mercury at Dumont d'Urville, East Antarctic coast: continental outflow and oceanic influences

et al. 2016

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Abstract. Under the framework of the Global Mercury Observation System (GMOS) project, a 3.5-year record of atmospheric gaseous elemental mercury (Hg(0)) has been gathered at Dumont d'Urville (DDU, 66 • 40 S, 140 • 01 E, 43 m above sea level) on the East Antarctic coast. Additionally, surface snow samples were collected in February 2009 during a traverse between Concordia Station located on the East Antarctic plateau and DDU. The record of atmospheric Hg(0) at DDU reveals particularities that are not seen at other coastal sites: a gradual decrease of concentrations over the course of winter, and a daily maximum concentration around midday in summer. Additionally, total mercury concentrations in surface snow samples were particularly elevated near DDU (up to 194.4 ng L −1 ) as compared to measurements at other coastal Antarctic sites. These differences can be explained by the more frequent arrival of inland air masses at DDU than at other coastal sites. This confirms the influence of processes observed on the Antarctic plateau on the cycle of atmospheric mercury at a continental scale, especially in areas subject to recurrent katabatic winds. DDU is also influenced by oceanic air masses and our data suggest that the ocean plays a dual role on Hg (0) concentrations. The open ocean may represent a source of atmospheric Hg(0) in summer whereas the sea-ice surface may provide reactive halogens in spring that can oxidize Hg(0). This paper also discusses implications for coastal Antarctic ecosystems and for the cycle of atmospheric mercury in high southern latitudes.

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Section: (A) Role Of Penguin Emissionsmentioning

confidence: 99%

Multi-year record of atmospheric mercury at Dumont d'Urville, East Antarctic coast: continental outflow and oceanic influences

et al. 2016

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“…Crawford et al, 2001;Davis et al, 2001Davis et al, , 2004Oncley et al 2004;Jones et al, 2008). Furthermore, the precise role that global circulation patterns play in the seasonal cycles of some trace species in Antarctica continues to challenge the global modelling community (Zhang et al, 2011(Zhang et al, , 2008Josse et al, 2004;Taguchi et al, 2002;Heinmann et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

Characterising terrestrial influences on Antarctic air masses using Radon-222 measurements at King George Island

et al. 2014

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Abstract. We report on one year of high-precision direct hourly radon observations at King Sejong Station (King George Island) beginning in February 2013. Findings are compared with historic and ongoing radon measurements from other Antarctic sites. Monthly median concentrations reduced from 72 mBq m −3 in late-summer to 44 mBq m −3 in late winter and early spring. Monthly 10th percentiles, ranging from 29 to 49 mBq m −3 , were typical of oceanic baseline values. Diurnal cycles were rarely evident and local influences were minor, consistent with regional radon flux estimates one tenth of the global average for ice-free land. The predominant fetch region for terrestrially influenced air masses was South America (47-53 • S), with minor influences also attributed to aged Australian air masses and local sources. Plume dilution factors of 2.8-4.0 were estimated for the most terrestrially influenced (South American) air masses, and a seasonal cycle in terrestrial influence on tropospheric air descending at the pole was identified and characterised.

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“…Argentini et al, 2005), reactive species interacting with the snow (e.g. Davis et al, 2001) and astronomical site quality (e.g. Tremblin et al, 2011).…”

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confidence: 99%

Genesis of diamond dust, ice fog and thick cloud episodes observed and modelled above Dome C, Antarctica

Ricaud¹,

Bazile²,

Guasta³

et al. 2017

Atmos. Chem. Phys.

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Abstract. Episodes of thick cloud and diamond dust/ice fog were observed during 15 March to 8 April 2011 and 4 to 5 March 2013 in the atmosphere above Dome C (Concordia station, Antarctica; 75 • 06 S, 123 • 21 E; 3233 m a.m.s.l.). The objectives of the paper are mainly to investigate the processes that cause these episodes based on observations and to verify whether operational models can evaluate them. The measurements were obtained from the following instruments: (1) a ground-based microwave radiometer (HAM-STRAD, H 2 O Antarctica Microwave Stratospheric and Tropospheric Radiometers) installed at Dome C that provided vertical profiles of tropospheric temperature and absolute humidity every 7 min; (2) daily radiosoundings launched at 12:00 UTC at Dome C; (3) a tropospheric aerosol lidar that provides aerosol depolarization ratio along the vertical at Dome C; (4) down-and upward short-and long-wave radiations as provided by the Baseline Surface Radiation Network (BSRN) facilities; (5) an ICE-CAMERA to detect at an hourly rate the size of the ice crystal grains deposited at the surface of the camera; and (6) space-borne aerosol depolarization ratio from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) lidar aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) platform along orbits close to the Dome C station. The time evolution of the atmosphere has also been evaluated by considering the outputs from the mesoscale AROME and the global-scale ARPEGE meteorological models. Thick clouds are detected during the warm and wet periods (24-26 March 2011 and 4 March 2013) with high depolarization ratios (greater than 30 %) from the surface to 5-7 km above the ground associated with precipitation of ice particles and the presence of a supercooled liquid water (depolarization less than 10 %) clouds. Diamond dust and/or ice fog are detected during the cold and dry periods (5 April 2011 and 5 March 2013) with high depolarization ratios (greater than 30 %) in the planetary boundary layer to a maximum altitude of 100-300 m above the ground with little trace of precipitation. Considering 5-day back trajectories, we show that the thick cloud episodes are attributed to air masses with an oceanic origin whilst the diamond dust/ice fog episodes are attributed to air masses with continental origins. Although operational models can reproduce thick cloud episodes in the free troposphere, they cannot evaluate the diamond dust/ice fog episodes in the planetary boundary layer because they require to use more sophisticated cloud and aerosol microphysics schemes.

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Unexpected high levels of NO observed at South Pole

Cited by 201 publications

References 20 publications

Multi-year record of atmospheric mercury at Dumont d'Urville, East Antarctic coast: continental outflow and oceanic influences

Multi-year record of atmospheric mercury at Dumont d'Urville, East Antarctic coast: continental outflow and oceanic influences

Characterising terrestrial influences on Antarctic air masses using Radon-222 measurements at King George Island

Genesis of diamond dust, ice fog and thick cloud episodes observed and modelled above Dome C, Antarctica

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