Revised June 1993 (Appendices revised March 1994)
A.H. Manson (Chairman) Institute of Space and Atmospheric Studies University of Saskatchewan 116 Science Place Saskatoon, Saskatchewan S7N 5E2 Canada J.M. Forbes (Co-Chairman) Department of Aerospace Engineering Campus Box 429 Boulder, Colorado. 80309-042 U.S.A. *SCOSTEP/STEP approved. **Document prepared 1989.
During the years of MAP/MAC 1982-8, radars capable of sounding the mesosphere and lower thermosphere (MLT ~80-110 km) made a considerable contribution to studies of the dynamics of the upper middle atmosphere. Although their data reached into the thermosphere, and so exceeded early definitions of the extent of the middle atmosphere (20-90 km), the radars provided insights into the processes by which energy is distributed among the many scales of motion in this complex transitional region. This proved important also for the lower atmosphere, e.g. tides and gravity waves in this MLT region are diagnostic of the dynamics and photochemistry of the troposphere and stratosphere.
The activities of WITS (1987-1990) and the related and ongoing CEDAR program, led to the re-organization of the radars active in the projects of MAP/MAC into the MLT Network. They have been most active in the CEDAR/WITS " Lower Thermosphere Coupling Study " (LTCS) project, but also GITCAD (which encompasses the whole thermosphere) and WAGS (a gravity wave study). As stated in the LTCS planning document " The Lower Thermosphere Coupling Study "(LTCS) is a coordinated investigation of the lower thermosphere (80-150 km) combining observational and numerical modelling efforts with the ultimate goal of better understanding the dynamic and electrodynamic processes coupling the mesosphere, lower thermosphere, and upper thermosphere atmospheric regions. ---- Emphasis will be placed on neutral winds, temperatures, electric fields, and electric currents determined during ---- coordinated measurement campaigns each consisting of a 30-day 'background' period and a 5-6 day 'core period'. The role of the MLT (Radar) Network has been to define, dynamically, the lower boundary and bottom (80-110 km) of the lower thermosphere (80-150 km) in terms of tides, and other planetary waves. LTCS is to be ongoing through CEDAR (1990-95).
It is considered highly desirable to formalise the status of the MLT network and the LTCS within STEP, as these community efforts engage in long term and campaign studies of an important and poorly understood region in the atmosphere, which includes the mesopause, the turbopause, large portions of the ionospheric D- and E-regions, including the dynamo region. It is the region through which the mesosphere and thermosphere are dynamically coupled, and hence bears relevance to the overall theme of STEP.
The Mesosphere Lower Thermosphere Coupling Study (MLTCS) of STEP is to be an investigation of the winds and waves (tidal, planetary, gravity) of the ~80-150 km region, and the coupling between the various scales of motion. The study will also necessarily involve some consideration of the electrodynamic mechanisms that lead to coupling between the magnetosphere, ionosphere and neutral atmosphere, and hence collaboration with GITCAD of STEP. It will principally involve radars as the observational systems, and will include numerical modelling efforts. It represents a merging of the LTCS and MLT network efforts. The LTCS will continue to operate as a U.S. national effort as part of the CEDAR program.
The MLT radar network includes over 35 systems distributed globally, with about 50 active scientists; because it includes very active and experienced aeronomers we prefer to call it the " MLT Network ". The radar types include: medium frequency (MF) systems (~11) employing spaced antenna and interferometer techniques; meteor systems (~17) which often allow height ranging, but otherwise assign Doppler winds to ~95 km; low frequency sounders (~2), one of which includes height ranging; and MST systems (~7), which although providing stratospheric and tropospheric data, may also provide complementary data to the other radars in the 70-110 km region. (The MST systems will also have their own network activity within the Middle Atmosphere (WG IV of STEP)). The updated list of P.I., and the Network Map are appended.
Observational emphasis of the MLT radars will be placed upon regular campaigns of moderate length (10d), operating in alternate months, October, December 1989; February, April, etc., 1990; January, March --- 1991. Radars which can operate continuously will be encouraged to do so. This will allow the existing climatologies of prevailing winds, tides and gravity waves to be expanded to include years of maximum and minimum solar activity. The 10d intervals are chosen to include the World Geophysical Interval(WGI)/Priority Regular World Day (PRWD)/Quarterly World Day (QWD), etc. of each month and hence to encourage the maximum possibility of collaborative detailed studies of particular events using optical and I.S. radar systems. (There are few other instruments which provide winds in this height range, but those few which do, FPI (OH, green line) and lidars, will be encouraged to participate in the campaigns and MLTCS activities.) The radars will also operate during the shorter campaigns of LTCS (CEDAR) and GITCAD (CEDAR; new project of STEP also) which include other instruments. Finally the Network has applied to NASA-UARS for formal comparative studies in 1991/2 with their WINDII and HRDI instruments.
There also exists an incoherent scatter (IS) radar network consisting of facilities at Sondrestrom, Millstone Hill, Arecibo, Jicamarca, and EISCAT. These radars are capable of inferring neutral temperatures and winds and other thermosphere/ionosphere properties between 100 and 140 km, as well as at higher altitudes. The IS radar network will participate in one to two 5- 6 day campaigns per year jointly with the MLT network. The main purpose of these campaigns will be to study the dynamical behaviour and coupling throughout the 80-130 km region, to provide direction to modelling and theoretical studies involving mesosphere/thermosphere coupling, and to test the performance of such models in this regime.
The focus of the whole study will be to better understand the dynamic coupling mechanisms which operate within the MLT regions: as such the study will be complementary to the LTCS (CEDAR) program. The extensive campaign activity of MLTCS will encourage existing MLT radar systems to continue their operations, into a period (1990-1995) when new systems at equatorial, sub-tropical, and polar latitudes are also functional, and when UARS is in orbit. The existance of such expanded climatologies will be of great value for thermospheric campaign-studies such as LTCS (CEDAR) and GITCAD (CEDAR, STEP), as they will enable the lower boundary of the thermosphere to be defined for all months of the year and for a variety of solar/magnetospheric conditions, and not just for a few campaigns of limited duration. The work of the MLTCS project will also be of significance for the development of Middle Atmosphere dynamical projects (WG IV), e.g. a tidal project would focus upon better defining the forcing of the various tidal modes in the lower and middle atmosphere, but also upon the resulting tides in the MLT region and above.
The IS radars have already been very active in the WAGS(WITS) project, which has focussed upon the propagation of gravity waves from high latitudes during auroral disturbances. An assessment of the more ubiquitous background flux of waves from the middle atmosphere, will allow comparisons to be made between IS and MLT radar data, and hence provide information on gravity wave propagation from 80-140 km.
The MST radars, but only a few of the more powerful MF radars, are capable of studying individual gravity wave events, and of measuring wave propagation characteristics. Such studies will naturally be focussed within WG IV, but there will be opportunities for collaboration between MLTCS and those activities.
Regarding workshops: CEDAR has regular annual workshops where LTCS activity and coordination occurs, and at which the IS radar community is very active. Workshops for the MLT network are best held under the umbrella of regular and continuing MST Radar Workshops. These began during MAP, and include the major radar types (MF, Meteor) in the MLT Network. Also the important GLOBMET Network has regular meetings where techniques and data analysis are discussed.
1991 Update. A wide variety of study groups have been set up as described in Appendix B. Initial results will be presented at COSPAR 1992, but their activities will go on for several years.
Alan Manson (Canada, Convenor). Bob Vincent (Australia, WG 4 of STEP; ICMUA (IAMAP); MF radars; Southern Hemiphere). Susan Avery (U.S.A., CEDAR; ST/Meteor radars). Yu. Portnyagin (Russia, GLOBMET Secretary; Meteor radars). Edward Kazimirovsky (Russia; WG 3 of STEP; LF radars).
It is proposed that this committee, plus co-chairman Jeff Forbes, who is the convenor of LTCS (CEDAR, WITS), and Joseph Salah (U.S., CEDAR; WITS; IS radar convenor) form the steering committee of the MLTCS Project of WG 3 STEP.
We are optimistic for the success of this project. The scientists involved have worked productively and creatively during MAP/MAC and WITS(CEDAR). The project stresses, naturally, coupling within the mesosphere and lower thermosphere, with thermospheric and magnetospheric regions above, and with the middle atmosphere (WG 4) below. As such it appears philosophically consistent with the goals of STEP.
S. Avery, Platteville, Col. (U.S.A.) 40oN, 104oW. ST/Meteor. 80-100 km. Operating in 1988. Xmas Island (2oN, 157oW. ST/Meteor 80-110 km. Operating in 1988. V. Belikovich, Gorky (Russia) 55oN, 44oE. M.F. 60-110 km. Operating in 1988. G. Cevolani, Bologna (Italy). 45oN, 12oW. Meteor. 75-115 km. Continuous. A.J. Chen, Chung-Li (Taiwan, Republic of China) 25oN, 121oE. MST/VHF. ~80 km (interim) campaigns. R. Clark, Durham (U.S.A.) 43oN, 71oW. Meteor. 80-110 km. Continuous. G. Fraser, Christchurch (New Zealand) 44oN, 173oE. M.F. 60-110 km; Scott Base 78oS, 167oE, M.F. 70-110 km. Continuous. D. Fritts, Boulder/Hawaii (U.S.A.) 22oN, 158#W. M.F. 60-100 km. Operating continuously from Sept. 1990. K. Greisiger, Kuhlungsborn (G.D.R.) 54oN, 12oE. Meteor. ~95 km. Continuous. T. Hansen,/A. Manson, C. Meek, Tromso (Norway) 70oN, 19oE. M.F. 80-110 km. 1987/8 continuous. (with Saskatoon M.F. system group). K. Igarashi, Yamagama (Japan) 31N, 131E, M.F. 60-110 km. Continuous S. Fukao, Shigaraki (Japan) 35oN, 136oE. MST/VHF. 60-90 km campaigns. E. Kazimirovsky, Irkutsk (Russia) 52oN, 105oE. L.F. ~95 km. Continuous. J. Lastovicka, Prague (Czechoslovakia) 44o-54oN, 7o-24oE. Multi-frequency absorption. 80-100 km. Continuous. S. Franke, Urbana (U.S.A.) 40oN, 88oW. MST. 75-95 km campaign/MF. 60-110 km. Operating in 1988. A. Manson/C. Meek, Saskatoon (Canada) 52oN, 107oW. M.F. 60-110 km. Continuous. Robsart 49N, 109W; Sylvan Lake 52N, 114W, MF 60-110 km. Continuous. J. MacDougall/W. Hocking London (Canada) 43N, 81W MF radar. 60-100 km continuous fron 1993. H. Monroy, Arecibo (Puerto Rico) 18oN, 67oW. M.F. 60-100 km. Campaigns since 1989. H. Muller, Sheffield (U.K.) 53oN, 2oW, Meteor. 80-110 km. Continuous. Also Aberdeen (M. Gadsden) 57oN, 2oW. D. Pancheva, Sofia (Bulgaria) 43oN, 24oE. Meteor/Absorption. 80-100 km. Continuous since 1990. L. Poole, Grahamstown (S. Africa) 33oS, 27oE. Meteor. Continuous. C. Reddi, Trivandrum (India) 9oN, 77oE. Meteor. R. Roper, Atlanta (U.S.A.) 18oN, 67oW. IDI/HF. 70-110 km. R. Ruster, Sousy (F.R.G.) Harz, 52oN, 10oE or Andenes (Norway) 69oN, 16oE. MST/VHF 75-95 km campaign (with P. Czechowsky). R. Schminder, Collm (G.D.R.) 51oN, 13oE. L.F. profiler. 85-110 km. Continuous (with D. Kurschner). W. Singer, Juliusruh (G.D.R.) 55oN, 13oE. M.F. (FM-CW). 50-90 km. Continuous since 1988. T. Tsuda/H. Wiryosumarto Kyoto/Jakarta (Japan/Indonesia) 6oS, 107oE. Meteor at Jakarta. 80-110 km. Continuous 1993-94. (with T. Nakamura: and Mrs. Sri Woro Harijono of Indonesia). T. Tsuda/T. Nakamura, Shigaraki (Japan) 35 N, 136 E. MST (Meteor Detection) 75-100 km campaigns R. Vincent, Adelaide (Australia) 35oS, 138oE. M.F. 60-98 km. Continuous (with I. Reid); Mawson, 68oS, 63oE. M.F. 70-108 km; Xmas Island 2oN, 157oW. M.F. 60-100 km. Continuous since 1990. V. Vlaskov, Murmansk (Russia) 69oN, 33oE. M.F. 60-100 km. Campaigns since 1990. R. Woodman, Jicamarca (Peru) 12oS, 74oW. MST/VHF (Meteor mode, I.S. mode also). ~50-85 km. Campaigns.
R. Chebotarjov, Dushanbe, Tajikistan 39oN, 69oE, 95 km, no height ranging. K. Karimov, Frunze, Kirgiz Rep. 43oN, 73oE, 95 km, no height ranging. B. Kashcheyev, Kharkov, Ukraine 50oN, 36oE, 80-110 km V. Nechitailenko Vice-Chairman (see Portnyagin, Secretary) of N.G.C. (data centre) O. Ovezgeldyev, Ashkhabad, Turkmenia 37oN, 59oE, 95 km, no height ranging Yu. Portnyagin Obninsk, Russia 55oN, 38oE; Volgograd, Russia 49oN, 44oE; Khabarovsk, Siberia 48oN, 135oE; Heiss Island, Russia 81oN, 58oE; Molodezhnaya, 67oS, 46oE. All 95 km, no height ranging. V. Sidorov, Kazan, Russia (Chairman of Meteor Research Section of N.G.C.) 56oN, 49oE, 80-110 km. key: M.F.: Medium Frequency (often spaced antenna). Meteor: VHF systems with height - ranging as marked. MST: VHF systems.
Arecibo (Puerto Rico) 18oN, 67oW J. Rottger/P. Williams, EISCAT (Tromso, Kiruna) 70oN, 20oE J. Salah, Millstone Hill (U.S.A.) 43oN, 71oW R. Johnson, Sondrestrom (Greenland) 67oN, 51oW
M.-L. Chanin/A. Hauchecorne, Verri‚res-le-Buisson (France) Lidars, stratosphere and mesosphere. OHP 44#N, 6#E; CEL 44#N, 7#W; LIMA 48#N, 4#W; LIRA (mobile lidar) variable. C. Gardner, Urbana (U.S.A.) 40oN, 88oW plus other locations. Lidars. Stratosphere and or mesosphere campaigns. A. Manson/D. McEwen, Saskatoon (Canada) 52oN, 107oW. FPI (OI 558, OH). 85, 98 km. Continuous. I. Reid/I. Bruce, Adelaide (Australia) 35#S, 138#E. FPI (OI 558, OH-724). 85, 98 km. Continuous. D. Rees, London (U.K.) FPI systems (standard instrument OI 630; new generation observes all useful mesospheric/thermospheric emissions and winds). Kiruna (Sweden) 67oN, 20oE; Kilpisjarvi (Finland) 68oN, 22oE; Bear Lake (Utah, USA) 42oN, 111oW; Svalbard (Norway) 78oN, 18oE. V. Wickwar, Logan, (U.S.A.) 42oN, 110oW (Bear Lake) FPI systems (OI 630, OI 558, OH) G. Witt/J. Stegman, Stockholm (Sweden) 59oN, 18oE Photometers (OI 557, OH 724, O2864, continuous); high resolution spectrometer (O2 UV airglow). Approximately 98, 85 km (airglow) continuous. B. Lowe, London (Canada) 43oN, 81oW FTS (1000-1700 nm, OH, O21D); scanning photometer (1200- 1700 nm). Also campaigns. Systems also at OHP 44oN, 5oE; Eureka 80oN, 85oW. R. Wiens, North York (Canada) 44oN, 80oW Emission rates, rotational temperatures of 02 atmosphericband (94 km); all-sky imager measures 4 airglow species (e.g. 94, 97 km); Michelson interferometer for winds (OI 630, 220 km; OI 558, 97 km, OH, 85 km). Also campaigns. Systems also at Bear Lake (42oN, 111oW). L. Cogger/G. Garbe, Calgary (Canada) 51oN, 114oW FPI (OI 630, OH) 220, 85 km, continuous; imaging monochromatic airglow camera (OI 558, OI 630, OH), continuous.
J. Forbes, Boston University (U.S.A.) (Co-Chairman MLTCS) F. Vial, Lab. de Meteorologie Dynamique, CNRS, France T. Aso, Kyoto University, Kyoto, JAPAN S. Miyahara, Kyushu University, Fukuoka, Japan R. Roble, NCAR-HAO, Boulder (U.S.A.) A. Richmond, NCAR-HAO, Boulder (U.S.A.) D. Rees, University College London (U.K.) T. Fuller-Rowell, NOAA/ERL/SEL, Boulder (U.S.A.) C. Fesen, Dartmouth College, New Hampshire (U.S.A.) R. Walterscheid, Aerospace Corp., Los Angeles, California (U.S.A.) R. Stening, University of New South Wales, Australia
John Holt, Millstone Hill, U.S.A. MIT Haystack Observatory, U.S.A. Belah Fejer, Jicamarca, Peru Utah State University, U.S.A. Craig Tepley, Arecibo, Puerto Rico NAIC/Arecibo Observatory, P.R. P.J.S. Williams, EISCAT, Norway/Sweden/Finland University College of Wales, Aberystwyth, U.K. Roberta Johnston, Sondrestrom, Greenland University of Michigan/Space Physics Research Laboratory, U.S.A.
Xmas Is 2N - Avery*/Vincent Puerto Rico 18N - Monroy Hawaii 22N - Fritts Adelaide 35S - Vincent Grahamstown - 33S - Poole Jakarta 6S - Wiryosumarto/Tsuda
Globmet radars Portnyagin* (regional leader) Sofia 43N - Pancheva Juliusruh 55N - Singer Collm 52N - Schminder Bologna 45N - Cevolani Saskatoon 52N - Manson/Meek Irkutsk 52N - Kazimirovsky Sylvan Lake 52N - Manson/Meek Urbana 40N - Liu/Franke Robsart 49N - Manson/Meek Jakarta 6S - Wiryosumarto/Tsuda Tromso 69N - Manson/Meek Kyoto 35N -Tsuda/Nakamura Harz 52N - Ruster
Durham 43N - Clark* Saskatoon 52N - Manson/Meek Irkutsk 52N - Kazimirovsky Tromso 69N - Manson/Meek Urbana 40N - Liu/Franke Sylvan Lake - Manson/Meek Hawaii 22N - Fritts Robsart - Manson/Meek Xmas Is 2N - Avery, Vincent Adelaide 35S - Vincent/Reid Christchurch 44S - Fraser Mawson 68S - Vincent/Reid Scott Base 78S - Fraser Sofia 43N - Pancheva Jakarta 6S - Wiryosumarto/Tsuda Kyoto 35N -Tsuda/Nakamura Harz 52N - Ruster
Tromso 69N - Manson/Meek Saskatoon 52N - Manson/Meek Juliusuruh 55N - Singer* Globmet - Portnyagin (regional leader) Irkutsk 52N - Kazimirovsky Mawson 68S - Vincent/Phillips Scott Base 78S - Fraser Sofia 43N - Pancheva
ISR Millstone Hill 43N - Salah* Eiscat 69N - Williams/Virdi Sondrestrom 69N - Johnson Arecibo 18N - Tepley MLT Durham 43N - Clark Tromso 69N - Manson/Meek Puerto Rico 18N - Monroy
7. LTCS 1-4 and MLTCS (#1 = LTCS 5 also in internal numbering) campaign studies including ISR and MLT data (Data from ISR, MLT ready, models exist)ISR/MLT communities/Forbes, Vial, Hagan models/Johnson* Note: ISR community have their own organization and data analysis plans, so 6. and 7. are subject to discussion with Joseph Salah. (MLTCS Working Group and ISR) and colleagues.
8. Long term variations in winds and tides; (QBO/ENSO) and solar cycle.Saskatoon 52N - Manson/Meek Irkutsk 52N - Kazimirovsky Collm 52N - Schminder
9. Gravity wave/tidal interactionsA research project has been established between Kyoto MU (Tsuda, Nakamura), Adelaide MF (Vincent, Reid), Saskatoon, Sylvan Lake, Robsart MF (Manson, Meek), Jakarta Meteor (Wiryosumarto, Tsuda), to explore latitudinal, hemispheric and seasonal variations.
Some global study may follow, and would be most desirable.
10. GW - Tide Modelling - Forbes/Miyahara.
11. GCM experiments - Forbes/Miyahara/Ebel.
12. 24-h Solar tide model (12 month) - Forbes/Vial/Hagan.
(10. - 12. were mentioned, proposed at Vienna IUGG by Forbes)
13. WINDII. MLTCS is collaborating in a series of radar comparisons.This isbeing co-ordinated by Marvin Geller of RSMA (STEP). Activity on this should begin in 1992.
........................ A.H. Manson *(leader)