秸秆饲料加工处理与利用工程可行性研究报告.pdf

GEOPHYSICAL RESEARCH LETTERS, VOL. 37, L09803, doi:, 2010
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Responses of mesosphere and lower thermosphere temperatures
to gravity wave forcing during stratospheric sudden warming
Chihoko Yamashita,1,2 Han‐Li Liu,1 and Xinzhao Chu2
Received 4 January 2010; revised 29 March 2010; accepted 2 April 2010; published 6 May 2010.
[1] We examine the responses of the mesosphere and lower Mesosphere‐Electrodynamics General Circulation Model
thermosphere (MLT) temperatures to gravity waves (GWs) (TIME‐GCM), the Navy‐Operational Global Atmospheric
during stratospheric sudden warming (SSW) using TIME‐ Prediction System ‐ Advanced Level Physics and High
GCM through modifying GW parameters. Our study Altitude (NOGAPS‐ALPHA), and the Canadian Middle
confirms that the height of GW forcing region is mainly Atmosphere Model Data Assimilation System (CMAM‐
determined by GW amplitude and wavelength, and its DAS) [Liu and Roble, 2002; Coy et al., 2005; Ren et al.,
vertical depth is closely tied to the spectral width of GW 2008]. The importance of GW forcing for capturing MLT
phase speed. The GW forcing controls the pattern and cooling has been examined using the NOGAPS‐ALPHA
strength of residual circulation and thereby the characteristics model with and without Rayleigh friction and the CMAM‐
of the MLT cooling and warming regions. The ary DAS model with and without a non‐orographic GW param-
wave (PW) forcing in the MLT also affects the vertical depth eterization [Coy et al., 2005; Ren et al., 2008]. In general,
and magnitude of MLT temperature anomalies through simulations with GWs considered gave more realistic results
further modifying the residual circulation. These PWs in in the MLT region than without the parameterization.
MLT are likely generated in‐situ by the GW forcing at high However, discrepancies still exist between simulations and
latitudes. Therefore, the mechanisms of GW controlling observations in