Structure, variability, and mean-flow interactions of the January 2015 quasi-two-day wave at middle and high southern latitudes

The structure, variability, and mean-flow interactions of the quasi-2-day wave (Q2DW) in the mesosphere and lower thermosphere during January 2015 were studied employing meteor and medium-frequency radar winds at eight sites from 23 degrees S to 76 degrees S and Microwave Limb Sounder (MLS) temperature and geopotential height measurements from 30 degrees S to 80 degrees S. The event had a duration of 20-25 days, dominant periods of 44-52 hr, temperature amplitudes as large as 16 K, and zonal and meridional wind amplitudes as high as 40 and 80 m/s, respectively, at middle and lower latitudes. MLS measurements enabled definition of balance winds that agreed well with radar wind amplitudes and phases at middle latitudes where amplitudes were large and quantification of the various Q2DW modes contributing to the full wave field. The Q2DW event was composed primarily of the westward zonal wavenumber 3 (W3) mode but also had measurable amplitudes in other westward modes W1, W2, and W4; eastward modes E1 and E2; and stationary mode S0. Of the secondary modes, W1, W2, and E2 had the larger amplitudes. Inferred MLS balance winds enabled estimates of the Eliassen-Palm fluxes for each mode, and cumulative zonal accelerations that were found to be in reasonable agreement with radar estimates from 35 degrees S to 70 degrees S at the lower altitudes at which radar winds were available

Statistics of sporadic iron and relation to atmospheric dynamics

At Rothera Research Station (67.3°S, 68.1°W), Antarctica, 296 h of day and nighttime Fe-Boltzmann temperature lidar data were accumulated in 2003. During this time, sporadic iron layers (FeS) were observed with an annual average occurrence probability of 14%. The peak altitude of the FeS layers was highest during the summer, with a fitted value of 103 km while during the winter the layer decreased in height to 90 km with an annual average of 97 km. The atmospheric temperature perturbations and potential energy density profiles computed from the same lidar data exhibited increased temperature but constant-with-height potential energy density when sporadic Fe layer occurred. Once sporadic Fe layers disappeared, the potential energy density decreased with height, indicating an energy loss due to atmospheric gravity wave breaking. These results suggest a link between FeS and atmospheric dynamics

The 2-day wave during the boreal summer of 1994

Copyright 2004 by the American Geophysical Union.The 2-day wave during the boreal summer of 1994 was observed using stratospheric analyses from the British Met Office and at mesospheric heights using medium-frequency (MF) radars and the microwave limb sounder (MLS) and high-resolution Doppler imager (HRDI) satellite instruments. Most of the evidence from our study points to a high latitude source for the boreal 2-day wave event we observed. We found little evidence for a connection between the 2-day wave event in the mesosphere and activity at lower altitudes. Instead we contend that the 2-day wave observed at upper mesospheric heights was excited in-situ. This event was predominantly zonal wave number 2, was highly localized in time, and the disturbance propagated equatorially from high northern latitudes. At stratopause and lower mesospheric heights the largest 2-day wave amplitudes were seen at high Southern Hemisphere latitudes (i.e., in the winter hemisphere). However, the austral winter 2-day wave was trapped and did not penetrate to upper mesospheric heights

磁気嵐時におけるグローバルな地磁気変動と電離圏擾乱ダイナモについて

第2回極域科学; 会場・会期: 2011年11月14日（月）-18日（金）: 国立極地研究所2階大会議室および国立国語研究所２階講

Equatorial dynamics observed by rocket, radar and satellite during the CADRE/MALTED campaign, 2: Mean and wave structures, coherence, and variability

We present an analysis of the wind and temperature measurements made by rocket, radar, and satellite instrumentation in the equatorial and subtropical middle atmosphere accompanying the MALTED/CADRE campaign conducted at Alcantara, Brazil during August 1994. Measured mean winds and temperatures extended from similar to 10 to 110 km, exhibited general consistency between instruments, and revealed an oscillatory nature of the mean zonal wind with altitude at equatorial latitudes. MF radar measurements of tidal structures showed these to exhibit variability on similar to 8- and 16-day periods, but to be largely uncorrelated in time. Two-day wave structures displayed the same periodicities, but were well correlated among sites at northern and equatorial latitudes. Rocket and radar measurements at smaller scales of motion revealed inertia-gravity waves having significant temporal coherence, quadrature correlations between components indicating clear directions of propagation, and momentum flux and mean wind correlations indicative of gravity wave filtering processes. Rochet estimates of diurnal tidal amplitudes suggest that the diurnal tide achieves convectively unstable amplitudes in the upper equatorial mesosphere.Fritts, DC; Hitchman, MH; Lieberman, RS; Reid, IM; Vincent, RA; Garten, JF; Riggin, DM; Goldberg, RA; Lehmacher, GA; Schmidlin, FJ; McCarthy, S; Kudeki, E; Fawcett, C