%0 Journal Article
%A Trinh, Quang Thai
%A Ern, Manfred
%A Doornbos, Eelco
%A Preusse, Peter
%A Riese, Martin
%T Satellite observations of middle atmosphere–thermosphere vertical coupling by gravity waves
%J Annales geophysicae
%V 36
%N 2
%@ 1432-0576
%C Katlenburg, Lindau
%I Copernicus
%M FZJ-2018-02206
%P 425 - 444
%D 2018
%X Atmospheric  gravity  waves  (GWs)  are  essentialfor  the  dynamics  of  the  middle  atmosphere.  Recent  stud-ies have shown that these waves are also important for thethermosphere/ionosphere (T/I) system. Via vertical coupling,GWs  can  significantly  influence  the  mean  state  of  the  T/Isystem. However, the penetration of GWs into the T/I sys-tem  is  not  fully  understood  in  modeling  as  well  as  obser-vations. In the current study, we analyze the correlation be-tween GW momentum fluxes observed in the middle atmo-sphere (30–90 km) and GW-induced perturbations in the T/I.In the middle atmosphere, GW momentum fluxes are derivedfrom  temperature  observations  of  the  Sounding  of  the  At-mosphere using Broadband Emission Radiometry (SABER)satellite instrument. In the T/I, GW-induced perturbations arederived from neutral density measured by instruments on theGravity field and Ocean Circulation Explorer (GOCE) andCHAllenging Minisatellite Payload (CHAMP) satellites. Wefind generally positive correlations between horizontal dis-tributions at low altitudes (i.e., below 90 km) and horizontaldistributions of GW-induced density fluctuations in the T/I(at 200 km and above). Two coupling mechanisms are likelyresponsible for these positive correlations: (1) fast GWs gen-erated in the troposphere and lower stratosphere can propa-gate directly to the T/I and (2) primary GWs with their ori-gins in the lower atmosphere dissipate while propagating up-wards  and  generate  secondary  GWs,  which  then  penetrateup to the T/I and maintain the spatial patterns of GW dis-tributions in the lower atmosphere. The mountain-wave re-lated hotspot over the Andes and Antarctic Peninsula is foundclearly in observations of all instruments used in our analy-sis. Latitude–longitude variations in the summer midlatitudesare also found in observations of all instruments. These vari-ations and strong positive correlations in the summer midlat-itudes suggest that GWs with origins related to convectionalso propagate up to the T/I. Different processes which likelyinfluence the vertical coupling are GW dissipation, possiblegeneration of secondary GWs, and horizontal propagation ofGWs. Limitations of the observations as well as of our re-search approach are discussed.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000427749900001
%R 10.5194/angeo-36-425-2018
%U https://juser.fz-juelich.de/record/844855