An analysis of large HNO_3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000
Large (>2 μm diameter) HNO_3-containing polar stratospheric cloud (PSC) particles were measured in situ by the NOAA NO_y instrument on board the NASA ER-2 aircraft during seven flights in the 1999/2000 Arctic winter vortex. Here we discuss the detection of these large PSC particles, their spatia...
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2002
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Online Access: | https://doi.org/10.1029/2001JD001079 |
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ftcaltechauth:oai:authors.library.caltech.edu:06v0z-mw456 2024-09-09T19:23:22+00:00 An analysis of large HNO_3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000 Northway, M. J. Gao, R. S. Popp, P. J. Holecek, J. C. Fahey, D. W. Carslaw, K. S. Tolbert, M. A. Lait, L. R. Dhaniyala, S. Flagan, R. C. Wennberg, P. O. Mahoney, M. J. Herman, R. L. Toon, G. C. Bui, T. P. 2002-10-27 https://doi.org/10.1029/2001JD001079 unknown American Geophysical Union https://doi.org/10.1029/2001JD001079 oai:authors.library.caltech.edu:06v0z-mw456 eprintid:59681 resolverid:CaltechAUTHORS:20150818-100656143 info:eu-repo/semantics/openAccess Other Journal of Geophysical Research. Atmospheres, 107(D20), Art. No. 8298, (2002-10-27) polar stratospheric clouds particles denitrification HNO_3 NAT NO_y info:eu-repo/semantics/article 2002 ftcaltechauth https://doi.org/10.1029/2001JD001079 2024-08-06T15:35:04Z Large (>2 μm diameter) HNO_3-containing polar stratospheric cloud (PSC) particles were measured in situ by the NOAA NO_y instrument on board the NASA ER-2 aircraft during seven flights in the 1999/2000 Arctic winter vortex. Here we discuss the detection of these large PSC particles, their spatial distribution, the ambient conditions under which they were detected, and our methods for interpreting NO_y time series with respect to particle sizes and number concentrations. The particles were observed through the use of two NO_y inlets on a particle separator extending below the ER-2 aircraft. The particle phase is assumed to be nitric acid trihydrate (NAT) or nitric acid dihydrate (NAD). Over a 48-day period, particles were sampled in the Arctic vortex over a broad range of latitudes (60–85°N) and altitudes (15–21 km). Typically, regions of the atmosphere up to 4 km above the observed large particle clouds were saturated with respect to NAT. Occasionally, large particles were measured in air subsaturated with respect to NAT, suggesting ongoing particle evaporation. Vortex minimum temperatures in the observation period suggest that synoptic-scale ice saturation conditions are not required for the formation of this type of particle. Three analytical methods are used to estimate size and number concentrations from the NO_y time series. Results indicate particle sizes between 5 and 20 μm diameter and concentrations from 10^(−5) to 10^(−3) cm^(−3). These low number concentrations imply a selective nucleation mechanism. Particle sizes and number concentrations were greater during the midwinter flights than the late winter flights. Knowledge of the geographical extent of large particles, actual sampling conditions, and particle size distributions offers multiple constraints for atmospheric models of PSC formation, which will lead to a better understanding of the process of denitrification and improvements in modeling future ozone loss. © 2002 American Geophysical Union. Received 9 July 2001; revised 28 ... Article in Journal/Newspaper Arctic Caltech Authors (California Institute of Technology) Arctic Midwinter ENVELOPE(139.931,139.931,-66.690,-66.690) Journal of Geophysical Research: Atmospheres 107 D20 |
institution |
Open Polar |
collection |
Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
unknown |
topic |
polar stratospheric clouds particles denitrification HNO_3 NAT NO_y |
spellingShingle |
polar stratospheric clouds particles denitrification HNO_3 NAT NO_y Northway, M. J. Gao, R. S. Popp, P. J. Holecek, J. C. Fahey, D. W. Carslaw, K. S. Tolbert, M. A. Lait, L. R. Dhaniyala, S. Flagan, R. C. Wennberg, P. O. Mahoney, M. J. Herman, R. L. Toon, G. C. Bui, T. P. An analysis of large HNO_3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000 |
topic_facet |
polar stratospheric clouds particles denitrification HNO_3 NAT NO_y |
description |
Large (>2 μm diameter) HNO_3-containing polar stratospheric cloud (PSC) particles were measured in situ by the NOAA NO_y instrument on board the NASA ER-2 aircraft during seven flights in the 1999/2000 Arctic winter vortex. Here we discuss the detection of these large PSC particles, their spatial distribution, the ambient conditions under which they were detected, and our methods for interpreting NO_y time series with respect to particle sizes and number concentrations. The particles were observed through the use of two NO_y inlets on a particle separator extending below the ER-2 aircraft. The particle phase is assumed to be nitric acid trihydrate (NAT) or nitric acid dihydrate (NAD). Over a 48-day period, particles were sampled in the Arctic vortex over a broad range of latitudes (60–85°N) and altitudes (15–21 km). Typically, regions of the atmosphere up to 4 km above the observed large particle clouds were saturated with respect to NAT. Occasionally, large particles were measured in air subsaturated with respect to NAT, suggesting ongoing particle evaporation. Vortex minimum temperatures in the observation period suggest that synoptic-scale ice saturation conditions are not required for the formation of this type of particle. Three analytical methods are used to estimate size and number concentrations from the NO_y time series. Results indicate particle sizes between 5 and 20 μm diameter and concentrations from 10^(−5) to 10^(−3) cm^(−3). These low number concentrations imply a selective nucleation mechanism. Particle sizes and number concentrations were greater during the midwinter flights than the late winter flights. Knowledge of the geographical extent of large particles, actual sampling conditions, and particle size distributions offers multiple constraints for atmospheric models of PSC formation, which will lead to a better understanding of the process of denitrification and improvements in modeling future ozone loss. © 2002 American Geophysical Union. Received 9 July 2001; revised 28 ... |
format |
Article in Journal/Newspaper |
author |
Northway, M. J. Gao, R. S. Popp, P. J. Holecek, J. C. Fahey, D. W. Carslaw, K. S. Tolbert, M. A. Lait, L. R. Dhaniyala, S. Flagan, R. C. Wennberg, P. O. Mahoney, M. J. Herman, R. L. Toon, G. C. Bui, T. P. |
author_facet |
Northway, M. J. Gao, R. S. Popp, P. J. Holecek, J. C. Fahey, D. W. Carslaw, K. S. Tolbert, M. A. Lait, L. R. Dhaniyala, S. Flagan, R. C. Wennberg, P. O. Mahoney, M. J. Herman, R. L. Toon, G. C. Bui, T. P. |
author_sort |
Northway, M. J. |
title |
An analysis of large HNO_3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000 |
title_short |
An analysis of large HNO_3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000 |
title_full |
An analysis of large HNO_3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000 |
title_fullStr |
An analysis of large HNO_3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000 |
title_full_unstemmed |
An analysis of large HNO_3-containing particles sampled in the Arctic stratosphere during the winter of 1999/2000 |
title_sort |
analysis of large hno_3-containing particles sampled in the arctic stratosphere during the winter of 1999/2000 |
publisher |
American Geophysical Union |
publishDate |
2002 |
url |
https://doi.org/10.1029/2001JD001079 |
long_lat |
ENVELOPE(139.931,139.931,-66.690,-66.690) |
geographic |
Arctic Midwinter |
geographic_facet |
Arctic Midwinter |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Journal of Geophysical Research. Atmospheres, 107(D20), Art. No. 8298, (2002-10-27) |
op_relation |
https://doi.org/10.1029/2001JD001079 oai:authors.library.caltech.edu:06v0z-mw456 eprintid:59681 resolverid:CaltechAUTHORS:20150818-100656143 |
op_rights |
info:eu-repo/semantics/openAccess Other |
op_doi |
https://doi.org/10.1029/2001JD001079 |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
107 |
container_issue |
D20 |
_version_ |
1809763780248207360 |