Studies of vertical and interhemispheric coupling during sudden stratospheric warmings (SSWs) suggest that gravity wave (GW) momentum ﬂux divergence plays a key role in forcing the middle atmosphere, although observational validation of GW forcing is limited. We present a whole atmosphere view of zonal winds from the surface to 100 km during the January 2013 major SSW, together with observed GW momentum ﬂuxes in the mesopause region derived from uninterrupted high resolution meteor radar observations from a SKiYMET system located at Trondheim, Norway (63◦N, 10◦11 E). Observations show GW momentum ﬂux divergence six days prior to the SSW onset producing an eastward forcing with peak values of ∼+145±60 ms−1day−1. As the SSW evolves, GW forcing turns westward, reaching a minimum of ∼-240±70 ms−1day−1 ∼+18 days after the SSW onset. These results are discussed in light of previous studies and simulations using the Whole Atmosphere Community Climate Model with Speciﬁed Dynamics (WACCM-SD).
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