TY  - JOUR
AU  - Trinh, Quang Thai
AU  - Ern, Manfred
AU  - Doornbos, Eelco
AU  - Preusse, Peter
AU  - Riese, Martin
TI  - Satellite observations of middle atmosphere–thermosphere vertical coupling by gravity waves
JO  - Annales geophysicae
VL  - 36
IS  - 2
SN  - 1432-0576
CY  - Katlenburg, Lindau
PB  - Copernicus
M1  - FZJ-2018-02206
SP  - 425 - 444
PY  - 2018
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000427749900001
DO  - DOI:10.5194/angeo-36-425-2018
UR  - https://juser.fz-juelich.de/record/844855
ER  -