|Faculty of Physics and Earth Science||
Middle and Upper Atmosphere
The mesosphere/lower thermosphere (MLT) is one of the scientifically
most challenging regions of the atmosphere.
The MLT is the region where wave-wave and wave-mean flow interaction processes
lead to a mean circulation regime
that is extremely far from radiative equilibrium.
Although radar measurements of MLT winds are possible since more than half a
century, our current knowledge on MLT dynamics
is still far from complete, mostly due to incomplete coverage of the global wind
field by ground-based remote sensing system.
As a contribution to our knowledge of MLT dynamics a SKiYMET meteor radar is operated at Collm Observatory (51.3°N, 13°E) continuously since August 2004. The measurements deliver hourly wind information in the height range 80-100 km and daily mean temperatures near the mesopause. Together with the earlier LF wind measurements peformed at Collm 1959-2008 a unique MLT circulation parameter dataset is available.
Recently, the MMARIA (Multi-static, Multifrequency Agile Radar for Investigations of the Atmosphere) concept of a multi-static VHF meteor radar network to derive horizontally resolved wind fields in the mesosphere–lower thermosphere was introduced, using two transmitters located at Juliusruh and Collm, and several receiving links (Stober et al., 2018). This allows to retrieve horizontally resolves winds over Eastern Germany.
Two antennas, as part of the interferometer of the Collm radar
6-year mean zonal prevailing winds over Collm (from Jacobi, 2012)
Horizontally resolved winds from the MMARIA network (from Stober et al., 2018)
Jacobi, Ch., C. Geißler, F. Lilienthal, and A. Krug, 2018: Forcing mechanisms of the 6-hour tide in the mesosphere/lower thermosphere, Adv. Radio Sci., 16, 141-147, https://doi.org/10.5194/ars-16-141-2018.
Stober, G., J.L. Chau, J. Vierinen, J., Ch. Jacobi, and S. Wilhelm, 2018: Retrieving horizontally resolved wind fields using multi-static meteor radar observations, Atmos. Meas. Tech., 11, 4891-4907, https://doi.org/10.5194/amt-11-4891-2018.
Jacobi, Ch., A. Krug, and E. Merzlyakov, 2017: Radar observations of the quarterdiurnal tide at midlatitudes: Seasonal and long-term variations, J. Atmos. Sol.-Terr. Phys., 163, 70-77, https://doi.org/10.1016/j.jastp.2017.05.014.
Jacobi, Ch., T. Ermakova, D. Mewes, and A.I. Pogoreltsev, 2017: El Niño influence on the mesosphere/lower thermosphere circulation at midlatitudes as seen by a VHF meteor radar at Collm (51.3°N, 13°E), Adv. Radio Sci., 15, 199-206, https://doi.org/10.5194/ars-15-199-2017.
Stober, G., V. Matthias, Ch. Jacobi, S. Wilhelm, J. Höffner und J. L. Chau, 2017: Exceptionally strong summer-like zonal wind reversal in the upper mesosphere during winter 2015/16, Ann. Geophys., 35, 711-720, doi:10.5194/angeo-35-711-2017
Wu, Q., A. Maute, V. Yudin, L. Goncharenko, J. Noto, R. Kerr, and C. Jacobi, 2016: Observations and Simulations of Mid Latitude Ionospheric and Thermospheric Response to the January 2013 Stratospheric Sudden Warming Event, J. Geophys. Res. Space Physics, 121, 8995–9011, doi:10.1002/2016JA023043.
Jacobi, Ch., F. Lilienthal, C. Geißler, and A. Krug, 2015: Long-term variability of mid-latitude mesosphere-lower thermosphere winds over Collm (51°N, 13°E), J. Atmos. Sol.-Terr. Phys., 136, B, 174–186, doi:10.1016/j.jastp.2015.05.006.
Lilienthal, F., and Ch. Jacobi, 2015: Meteor radar quasi two-day wave observations over 10 years at Collm (51.3°N, 13.0°E), Atmos. Chem. Phys., 15, 9917-9927, doi:10.5194/acp-15-9917-2015.
Jacobi, Ch., 2014: Meteor heights during the recent solar minimum, Adv. Radio Sci., 12, 161-165.
Jacobi, Ch., C. Arras, and J. Wickert, 2013: Enhanced sporadic E occurrence rates during the Geminid meteor showers 2006-2010, Adv. Radio Sci., 11. 313-318.
Stober, G., Ch. Jacobi, V. Matthias, P. Hoffmann, and M. Gerding, 2012: Neutral air density variations during strong planetary wave activity in the mesopause region derived from meteor radar observations. J. Atmos. Sol.-Terr. Phys., 74, 55-63, doi:10.1016/j.jastp.2011.10.007
Jacobi, Ch., 2012: 6 year mean prevailing winds and tides measured by VHF meteor radar over Collm (51.3°N, 13.0°E). J. Atmos. Solar-Terr. Phys., 78–79, 8–18, doi:10.1016/j.jastp.2011.04.01.
Placke, M., P. Hoffmann, E. Becker, Ch. Jacobi, W. Singer, and M. Rapp, 2011: Gravity wave momentum fluxes in the MLT – Part II: Meteor radar investigations at high and midlatitudes in comparison with modeling studies. J. Atmos. Solar–Terr. Phys., 73, 911-920, doi:10.1016/j.jastp.2010.05.007.
Placke, M., G. Stober, and Ch. Jacobi, 2011: Gravity wave momentum fluxes in the MLT—Part I: Seasonal variation at Collm (51.3°N, 13.0°E). J. Atmos. Solar–Terr. Phys., 73, 904-910, doi:10.1016/j.jastp.2010.07.012.
Stober, G., Ch. Jacobi, and W. Singer, 2011: Meteoroid mass determination from underdense trails. J. Atmos. Solar-Terr. Phys., 73, 895-900, doi:10.1016/j.jastp.2010.06.009.
Arras, C., Ch. Jacobi, and J. Wickert, 2009: Semidiurnal tidal signature in sporadic E occurrence rates derived from GPS radio occultation measurements at midlatitudes. Ann. Geophys. 27, 2555–2563.
Jacobi, Ch., C. Arras, D. Kürschner, W. Singer, P. Hoffmann, and D. Keuer, 2009: Comparison of mesopause region meteor radar winds, medium frequency radar winds and low frequency drifts over Germany. Adv. Space. Res., 43, 247-252.
Last update 11 September 2018 by Ch. Jacobi