GATDAT - Global Airglow Transition Detection and Tracking

A new PSMOS campaign (approved by PSMOS Steering Committee, June 2001):
GATDAT - Global Airglow Transition Detection and Tracking

Dramatic airglow transitions close to the equinoxes, but also at other times of the year have been observed occasionally during the last decade (G. Shepherd et al. 1999; M. Shepherd et al. 2002; see refs given below).

First results indicate a relation to transients due to the seasonal shifting of planetary scale patterns (Liu and Roble 2001), but the details and the behaviour of transients in other seasons are still far from being well understood.

The small number of cases studied so far makes enhanced observational efforts mandatory. Therefore, a Global Airglow Transition Detection and Tracking (GATDAT) campaign is proposed for the next 2+ years, from 2001 to 2003. This campaign will exploit the recent creation of many new optical observation facilities, and the availability of others that are already in operation. The recent radar detection of zonal wind reversals related to airglow transitions at sites with varying separations (Manson et al. 2002; and unpublished results by Scheer, Reisin and Batista) suggest the need to also use the growing global network of radars, as well as satellite observations.

The collaboration by specialists who focus on different aspects of the data and their theoretical interpretation is encouraged.

Background and Details:

Known phenomena that are targets of the study include:

Sudden spring transitions in the high and midlatitude Northern Hemisphere (G. Shepherd et al. 1999; K. Shiokawa and Kiyama 2000; A. Manson et al. 2002; M. Shepherd et al. 2002),
Sudden autumn transitions in the high and midlatitude Northern Hemisphere (M. Taylor et al. 2001),
Prominent airglow bursts in the midlatitude Southern Hemisphere (Scheer and Reisin 2002).

We need to:

analyze more examples from previous STEP and PSMOS years 1991 - 2000, at low to high latitudes, equatorial, and especially Southern Hemisphere phenomena,
investigate the role of dynamics in these cases by performing additional modeling experiments with the TIME-GCM and CMAM models.

For those observations that cannot be operated continuously, it is desirable to suggest the following order of priority for focussed campaign time spans (depending on altitude):

         1. March to April (95 km)
         2. June to July (85 km)
         3. September to October (95 km)
         4. December (85 km)

These dates may be modified to include other Southern Hemisphere equinoxial transition intervals.

Strategy:

create a Campaign Committee (A. Manson, J. Scheer, M. Shepherd, M. Taylor)
acquisition of new data 2001-2003
identification of events (old data and new) in consultation with the local operators, or by the local operators themselves,
identification of study groups and principal investigators for each substantial event.

Preparation of reports:

Progress report 2002 (about spring/autumn 2001/2 results)
Paper development through 2003.

Boulder CO, June 23, 2001
A. Manson, J. Scheer

References:

Liu, H.-L., Roble, R.G., Taylor, M.J., and Pendleton, W.R.Jr.
Mesospheric planetary waves at northern hemisphere fall equinox, Geophys. Res. Lett. 28, 1903-1906, 2001.

Manson, A.H., Meek, C.E., Stegman, J., Espy, P.J., Roble, R.G., Hall, C.M., Hoffmann, P., and Jacobi, Ch.
Springtime transitions in mesopause airglow and dynamics: photometer and MF radar observations in the Scandinavian and Canadian sectors, J. Atmos. Solar-Terr. Phys. 64(8-11), 1131-1146, 2002.

Scheer, J., and Reisin, E.R.
Most prominent airglow night at El Leoncito, J. Atmos. Solar-Terr. Phys. 64(8-11), 1175-1181, 2002.

G.G. Shepherd, Stegman, J., Espy, P., McLandress, C., Thuillier, G., and Wiens, R.H.
Springtime transition in lower thermospheric atomic oxygen, J. Geophys. Res. 104, 213-223, 1999.

M.G. Shepherd, P.J. Espy, C.Y. She, W. Hocking, P. Keckhut, G. Gavrilyeva, G.G. Shepherd, B. Naujokat
Springtime transition in upper mesospheric temperature in the northern hemisphere, J. Atmos. Solar-Terr. Phys. 64(8-11), 1183-1199, 2002.

Shiokawa, K., and Kiyama, Y.
A search for the springtime transition of lower thermospheric atomic oxygen using long-term midlatitude airglow data, J. Atmos. Solar-Terr. Phys. 62, 1215-1219, 2000.

Taylor, M.J., Pendleton, W.R.Jr., Liu, H.-L., She, C.Y., Gardner, L.C., Roble, R.G., and Vasoli, V.
Large amplitude perturbations in mesospheric OH Meinel and 87-km Na lidar temperatures around the autumnal equinox, Geophys. Res. Lett. 28, 1899- 1902, 2001.

updated: 14 June 2002

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