TY - JOUR
T1 - Seasonal and geographic variations of methanesulfonic acid in the arctic troposphere
AU - Li, S. M.
AU - Barrie, L. A.
AU - Talbot, R. W.
AU - Harriss, R. C.
AU - Davidson, C. I.
AU - Jaffrezo, J. L.
N1 - Funding Information:
Acknowledoement--SML acknowledges support of the National Center for Atmospheric Research, Boulder, Colorado in obtaining the MSA data from Barrow, Alaska and the Atmospheric Environment Service in data analyses. RWT and RCH acknowledge support from the NASA Global Tropospheric Chemistry program and thank the personnel of the Wallops Flight Facility for supporting operations aboard the NASA Electra research aircraft during ABLE3B.
PY - 1993/12
Y1 - 1993/12
N2 - Measurements in the Arctic troposphere over several years show that MSA concentrations in the atmospheric boundary layer, 0.08-6.1 parts per trillion (ppt, molar mixing ration), are lower that those over mid-latitude oceans. The seasonal cycle of MSA at Alert, Canada (82.5°N, 62.3°W), has two peaks of 6 ppt in March-April and July-August and minima of 0.3 ppt for the rest of the year. At Dye 3 (65°N, 44°W) on the Greenland Ice Sheet, a similar seasonal MSA cycle is observed although the concentrations are much lower with a maximum of 1 ppt. Around Barrow, Alaska (71.3°N, 156.8°W), MSA is between 1.0 and 25 ppt in July, higher than 1.5 ± 1.0 ppt in March-April. The mid-tropospheric MSA level of 0.6-1 ppt in the summer Arctic is much lower than about 6 ppt in the boundary layer. At Alert, the ratio of MSA to non-sea-salt (nss) SO42- ranges from 0.02 to 1.13 and is about 10 times higher in summer than in spring. The summer ratios are higher than found over mid-latitude regions and, when combined with reported sulfur isotope compositions from the Arctic, suggest that on average a significant fraction (about 16-23%) of Arctic summer boundary layer sulfur is marine biogenic. The measurements show that the summer Arctic boundary layer has a significantly higher MSA/nss-SO42- ratio than aloft.
AB - Measurements in the Arctic troposphere over several years show that MSA concentrations in the atmospheric boundary layer, 0.08-6.1 parts per trillion (ppt, molar mixing ration), are lower that those over mid-latitude oceans. The seasonal cycle of MSA at Alert, Canada (82.5°N, 62.3°W), has two peaks of 6 ppt in March-April and July-August and minima of 0.3 ppt for the rest of the year. At Dye 3 (65°N, 44°W) on the Greenland Ice Sheet, a similar seasonal MSA cycle is observed although the concentrations are much lower with a maximum of 1 ppt. Around Barrow, Alaska (71.3°N, 156.8°W), MSA is between 1.0 and 25 ppt in July, higher than 1.5 ± 1.0 ppt in March-April. The mid-tropospheric MSA level of 0.6-1 ppt in the summer Arctic is much lower than about 6 ppt in the boundary layer. At Alert, the ratio of MSA to non-sea-salt (nss) SO42- ranges from 0.02 to 1.13 and is about 10 times higher in summer than in spring. The summer ratios are higher than found over mid-latitude regions and, when combined with reported sulfur isotope compositions from the Arctic, suggest that on average a significant fraction (about 16-23%) of Arctic summer boundary layer sulfur is marine biogenic. The measurements show that the summer Arctic boundary layer has a significantly higher MSA/nss-SO42- ratio than aloft.
KW - Aerosol
KW - Arctic
KW - Greenland ice
KW - biogeochemical cycle
KW - methanesulfonic acid
KW - organic sulfur
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U2 - 10.1016/0960-1686(93)90333-T
DO - 10.1016/0960-1686(93)90333-T
M3 - Article
AN - SCOPUS:0027769640
SN - 0960-1686
VL - 27
SP - 3011
EP - 3024
JO - Atmospheric Environment Part A, General Topics
JF - Atmospheric Environment Part A, General Topics
IS - 17-18
ER -