Some observations of possible Stratospheric-Tropospheric

Exchange (STE) on 4/1-3/2008

Kurt Kebschull

CTDEP

4/15/2008

STE in the Northeastern US

• Could naturally formed ozone from the stratosphere play a role in enhancing surface monitored ozone?

• Will it cause an interraction with updated ozone standards?

• STE occurs behind strong frontal systems

Surface weather for 4/2/2008 00z, 8pm 4/1/08

Stratospheric intrusions can be involved w/ very dry air circulated out of the stratosphere

1715Z 4/1/08 Water vapor image highlights dry air folding into strong weather

systems

Whiteface Mt, NY el ~1500m

16Z

21Z

FROPA

http://www.dec.ny.gov/airmon/index.php/

CNW el. ~500m

Wind direction goes N, O3 goes up-counterintuitive

Missing wd data

Waterbury wd record for missing wd data

Note the “tongue” of TOMS total column ozone moving across the NE US. 400 du ~ 400ppb at max elev.

Near tropopause level analysis

jet

9000m (near tropopause) 120 hr back trajectory from GFS model analysis to Cornwall,CT and Saranac Lake, NY

Very deep mixing

Very strong subsidence inversion at 600mb, wind jet max at the break, very dry air! Stratospheric intrusion?

Some links on the state-of the-art science on STE (must be in slideshow mode to

activate links)• http://cimss.ssec.wisc.edu/goes/misc/99032

9.html

• http://www.atmos.umd.edu/~dkuhl/documents/Kuhl_Tropopause_Folding.ppt

• http://science.jrank.org/pages/4973/Ozone-Layer-Depletion-Stratospheric-ozone.html

tropfoldlooop4-1-3-80.gif

Double click link (in edit mode) for water vapor loop from 1715z 4/1- 0315z 4/3 at 30 min intervals, some images missing on 4/1. Ozone seems to be brought down in the dry air mass, but can linger aloft for a couple of days

Animation1.gif

Double click link below for GOES Ozone Sounder loop from 4/1- 4/3 at 30 min intervals, Early morning images are dark. High column ozone shows in red and green. Red area lingers for several hours

Link

When in slide show mode single click object

Double click link for water vapor loop from 1715z 4/1- 0315z 4/3 at 30 min intervals, some images missing on 4/1. Ozone is brought down in the dry air mass, but can linger aloft for a couple of days

Ex7.htm

GOES Ozone Sounder loop from 4/1- 4/3/08 at 60 min intervals, High column ozone shows in red and green. Red area lingers for several hours. Heavy cloud cover masks total column ozone (Images courtesy of SSEC, U. Wisconsin)

When in slide show mode single click object

Ex6.htm

A time series of ozone at some high elevation sites (and W Buxton, ME). W. Buxton has fresh NO knocking down O3 each day, but reaches near 60 on a “clean” day. Ozone lingers at high elevation sites.

WFC MT, NY MOMO,CT

MTW, NH UNDERHILL, VT

W BUXTON, ME

60 60

6060

60

STE Observation conclusions

• In this instance, the ozone approached but did not exceed the standard of 75 ppb/8hr and is likely not to do so.

• It may, however, may be worth watching, when ozone anomalously increases.

• At high elevation sites, naturally occurring ozone may linger and unintentionally affect non-attainment designations for places like Whiteface Mt, Mohawk Mt, Mt Washington and Cadillac Mt)

References and Abstracts• Akadémiai Kiadó - Journal of Radioanalytical and Nuclear Chemistry - Journal Article, Beryllium-7 as a

tracer of stratospheric ozone: A case study Authors : J. Tremblay1, R. Servranckx11Environment Canada Atmospheric Environment Service 100 Alexis-Nihon H4M 2N8 Saint-Laurent Quebec (Canada)

• By using the7Be/ozone upper atmosphere ratio, the study concludes that, over these two days, the convective mixing of the atmosphere could have been responsible for a recorded 48 hour average 18% increase in ground-level ozone concentrations.

• Determination of stratospheric ozone at ground level using Be-7/ozone ratios, Publication: Geophysical Research Letters, vol. 6, Mar. 1979, p. 171-174. (GeoRL Homepage) Publication Date: 03/1979 Authors: Dutkiewicz, V. A.; Husain, L. Affiliation: AA(New York State, Dept. of Health, Div. of Laboratories and Research, Albany, N.Y.), AB(New York State, Dept. of Health, Div. of Laboratories and Research, Albany, N.Y)

• Abstract Several studies have demonstrated the viability of using Be-7 as a natural radioactive tracer to identify upper atmospheric air at ground level. Elevated ozone concentrations are observed to correlate with periods of high Be-7 activity. Although correlations between Be-7 and O3 identify the presence ofstratospheric air, such data are not sufficient to quantify the stratospheric contributions, as ozone is also produced at ground level. To accurately determine the stratospheric contributions from Be-7 and O3 studies it is essential to know the Be-7/O3 concentration ratios in the stratosphere and the behavior of Be-7 aerosol and O3 during the descent through the troposphere. A description is in this connection presented of the first direct measurements of Be-7/O3 ratios in the stratosphere and upper troposphere.

References and Abstracts• Summertime ozone at Mount Washington: Meteorological controls at the highest peak in the northeast

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, D24303, doi:10.1029/2004JD004841, 2004, Emily V. Fischer, Climate Change Research Center, Institute for the Study of Earth Oceans and Space, University of New Hampshire, Durham, New Hampshire, USA, Robert W. Talbot, Climate Change Research Center, Institute for the Study of Earth Oceans and Space, University of New Hampshire, Durham, New Hampshire, USA, Jack E. Dibb Climate Change Research Center, Institute for the Study of Earth Oceans and Space, University of New Hampshire, Durham, New Hampshire, USA

• Most enhanced (90th percentile) and depleted (10th percentile) O3 events were short-lived and spread out over the summer months. Enhanced O3 events at Mount Washington were generally associated with westerly transporwhile depleted events corresponded to northwesterly transport. Periods of O3 greater than 80 ppbv during nighttime periods coincided with westerly (71%) and southwesterly (29%) transport. Periods of elevated O3 commonly occurred during regional warm sector flow or on the western edge of a surface anticyclone. Our analysis also identified a stratospheric contribution to a small percentage (5%) of extreme O3 events at the site, but more evidence is required to establish the significance of the contribution to background O3 levels in this region

References and AbstractsVol 450: 8 November 2007|, doi,10.1038/Nature 60312

Detection of stratospheric ozone intrusions by windprofiler radars

W. K. Hocking1, T. Carey-Smith 1,2, D. W. Tarasick2, P. S. Argall1, K. Strong3, Y. Rochon2, I. Zawadzki4,& P. A. Taylor5

1Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 3K7 Canada.,2Environment Canada, 4905 Dufferin Street, Downsview, Ontario, M3H5T4 Canada.,3Department of Physics, University of Toronto, 60 St George Street, Toronto, Ontario, M5S 1A7 Canada.,4Department of Atmospheric and Oceanic Sciences, McGill University, 805 Sherbrooke Street W., Montreal, Quebec, H3A 2K6 Canada.5Department of Earth and Science and Engineering, York University, 4700 Keele Street, Toronto, Ontario

Back-trajectory calculations and meteorological analyses indicated that a significant part of this ozone enhancement was stratospheric in origin. Ozone had entered the troposphere both above Montreal and as much as 1,000 km upstream to the west and northwest on 3 May, and the whole ozone enhancement moved downward and downstream as a layer. An initially upstream component reached the ground in Montreal on7 May. Ground-level values at these stations before and after the two events of 30 April–2 May and 6–9 May to were typically 15 p.p.b. at night and 30 p.p.b. during the day, but during the event of 6–9 May were typically 30 p.p.b. (night-time) to 50 p.p.b. (daytime). Stratospheric ozone had a large impact on the surface ozone densities, even in a large city in which photochemical effects might have been expected to dominate

• nature06312.pdf