The importance of atmospheric measurements at Alert, Canada

Atmospheric Environment, 2002

Polar meteorology and …, 2003

The Arctic Airborne Measurement Program ,**, (AAMP *,) campaign was carried out in March ,**, as one of the sub programs of the project "Variations of atmospheric constituents and their climate impact in the Arctic". The main goal of the project was to investigate the transport, transformation and radiative e#ect of trace gases and aerosols, and their role in the global climate. An instrumented jet plane, Gulfstream II (G-II), was flown from Nagoya, Japan via Barrow, Alaska to Longyearbyen (12ῌN, +/ῌE), Svalbard, crossing the Arctic Ocean in the lower stratospher. Three local flights were made over the Greenland Sea around Svalbard and two profile flights near Barrow. The plane was equipped with CO, and ozone analyzers, gas and aerosol sampling systems, aerosol particle counter, nephelometer, absorption photometer, PMS particle probes, sunphotometer, dew point hygrometer and dropsonde system. During the campaign, intensitive surface operations were also conducted at Ny-A ÷lesund (13ῌN, +,ῌE), Svalbard. Vertical profiles of several trace gases gave information about transport, a new observation by sunphotometer derived an aerosol optical depth in the stratosphere, and another new observation by dropsonde gave information on the polar vortex.

Atmospheric Chemistry and Physics, 2010

Bulletin of the American Meteorological Society, 2016

International Arctic Systems for Observing the Atmosphere (IASOA) activities and partnerships were initiated as a part of the 2007–09 International Polar Year (IPY) and are expected to continue for many decades as a legacy program. The IASOA focus is on coordinating intensive measurements of the Arctic atmosphere collected in the United States, Canada, Russia, Norway, Finland, and Greenland to create synthesis science that leads to an understanding of why and not just how the Arctic atmosphere is evolving. The IASOA premise is that there are limitations with Arctic modeling and satellite observations that can only be addressed with boots-on-the-ground, in situ observations and that the potential of combining individual station and network measurements into an integrated observing system is tremendous. The IASOA vision is that by further integrating with other network observing programs focusing on hydrology, glaciology, oceanography, terrestrial, and biological systems it will be po...

2000

The ESMOS/Arctic II project addresses the issues of Arctic ozone depletion and its causes. Within the project changes in the composition of the Arctic stratosphere have been observed by a network of stations and analysed by performing long-term measurements, assuring instrumental quality standards, supplemented by analysing collected data sets, performing case studies, and stratospheric aerosol and chemical trajectory modelling. Collected data have been shared via European and international databases.

2003

The Atmospheric Chemistry Experiment (ACE) is a Canadian scientific satellite mission performing remote sensing measurements of the Earth's atmosphere. Three ACE Arctic validation campaigns have been conducted at Eureka (Canada) between February and April in 2004, 2005 and 2006. This period coincides with the most chemically active time of year in the Arctic and also, at this time, there are a significant number of ACE satellite measurements near Eureka. The polar vortex regularly passes over the campaign site so measurements both inside and outside the vortex region can usually be made from this location. A suite of ten ground-based and balloon-borne instruments made observations during the measurement campaigns. This paper discusses the ozone total column and profile comparisons from the 2004 and 2005 campaigns and presents preliminary results from the recently completed 2006 campaign.

Journal of Geophysical Research, 1994

Concentrations of 7Be and 21øpb in 2 years of weekly high-volume aerosol samples collected at Alert, Northwest Territories, Canada, showed pronounced seasonal variations. We observed a broad winter peak in 2•øpb concentration and a spring peak in 7Be. These peaks were similar in magnitude and duration to previously reported results for a number of stations in the Arctic Basin. Beryllium 10 concentrations (determined only during the first year of this study) were well correlated with those of 7Be; the atom ratio •øBe/7Be was nearly constant at 2.2 throughout the year. This relatively high value of XøBe/7Be indicates that the stratosphere must constitute an important source of both Be isotopes in the Arctic troposphere throughout the year. A simple mixing model based on the small seasonal variations of •øBe/7Be indicates an approximately twofold increase of stratospheric influence in the free troposphere in late summer. The spring maxima in concentrations of both Be isotopes at the surface apparently reflect vertical mixing in rather than stratospheric injections into the troposphere. We have merged the results of the Be-based mixing model with weekly 03 soundings to assess Arctic stratospheric impact on the surface 03 budget at Alert. The resulting estimates indicate that stratospheric inputs can account for a maximum of 10-15% of the 03 at the surface in spring and for less during the rest of the year. These estimates are most uncertain during the winter. The combination of Be isotopic measurements and 03 vertical profiles could allow quantification of the contributions of 03 from the Arctic stratosphere and lower latitude regions to the 03 budget in the Arctic troposphere. Although at present the lack of a quantitative understanding of the temporal variation of 03 lifetime in the Arctic troposphere precludes making definitive calculations, qualitative examples of the power of this approach are given.

ARCTIC, 2013

Atmospheric Environment, 2002

Oxygenated hydrocarbons, including for the first time alcohols, in the atmosphere and snow-pack interstitial air were measured at Alert, Nunavut, Canada from 15 February to 5 May 2000. Unexpectedly high concentrations of oxygenated hydrocarbons were observed. Acetone, acetaldehyde and methanol represent about 90% of all oxygenated hydrocarbons measured in this work, and together with formaldehyde their total concentration was higher than the sum of measured NMHCs. During sunlit hours, concentrations in the snow-pack interstitial air were higher than those measured in the gas-phase, implying a positive flux from the snow-pack to the Arctic boundary layer. Fluxes of acetaldehyde, acetone and methanol at that time were estimated to be 26, 7.5 and 3.2 Â 10 8 molecules cm À2 s À1 , respectively. These rates would deplete the local snow of acetaldehyde and acetone in about 2 days if degassing was driving the flux. Additional evidence suggests that photochemical production in the snow-pack could explain these fluxes, especially for acetaldehyde. Diel variations were observed at Alert after polar sunrise in the snow-pack interstitial air and in ambient air. During decreasing O 3 conditions, positive correlation with acetaldehyde was observed which is interpreted as implying local Br driven chemistry, but acetone mixing ratios showed a strong negative correlation. Crown

Journal of Geophysical Research: Atmospheres

Observations from 1980 to 2013 of 20 aerosol constituents, ozone and mercury at Alert, Canada (82.50°N, 62.35°W), were analyzed for trends and dominant factors of the Arctic haze during winter and spring. Trends reflect changing emissions in Eurasia, the main source region for surface pollution in the high Arctic. SO 4 2− , H + , NH 4 + , K + , Cu, Ni, Pb, Zn, nonsoil V, nonsoil Mn, and equivalent black carbon decreased between 23% and 80% as emissions declined rapidly in northern Eurasia during the early 1990s. NO 3 − increased by 20% as aerosol acidity declined. Metals were linked to emissions from smelting and fossil fuel combustion. In winter, ozone increased by 5% over 23 years, consistent with other observations and global modeling. Twelve PMF factors emerged for the dark period (November to February) and 13 for the light period (March to May). Eleven PMF factors are common to both dark and light, a twelfth factor was associated with sulfate in the dark and nitrate in the light, and the thirteenth (light period) was related to ozone and gaseous mercury depletion near Alert. IODINE and NITRATE factors, important for Arctic chemistry, changed with sunlight. In the light, 50% of all NO 3 − was on the NITRATE factor, while in the dark, most was associated with MODIFIED SEA SALT and equivalent black carbon. In the dark (light), 90% (28%) of iodine were found on the factor IODINE and 58% associated with SEA-SALT and MODIFIED SEA-SALT. These results help in understanding the role of atmospheric chemistry in weather and climate processes. 1. Introduction Anthropogenic aerosol constituents and gases in the Arctic lower troposphere are most abundant in the colder half of the year (November to May). Lower wet and dry removal in winter/spring relative to summer results in longer aerosol lifetimes (