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Evidence of long‐term change in zonal wind in the tropical lower mesosphere: Observations and model simulations
Author(s) -
Venkat Ratnam M.,
Kishore Kumar G.,
Venkateswara Rao N.,
Krishna Murthy B. V.,
Laštovička Jan,
Qian Liying
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/grl.50158
Subject(s) - mesosphere , atmospheric sciences , climatology , perturbation (astronomy) , environmental science , atmosphere (unit) , atmospheric dynamics , term (time) , general circulation model , geology , stratosphere , atmospheric circulation , gcm transcription factors , climate change , latitude , meteorology , physics , geodesy , oceanography , quantum mechanics
In recent years, the mesosphere (50 to 85–100 km) has evoked great scientific interest as long‐term changes due to global warming can be clearly captured due to the large perturbation amplitudes at these altitudes. In the present study, zonal wind observations between 70 and 80 km over the Indian region provided by rocketsonde (1977–1991), HRDI/UARS (1991–1999), and MST radar (1995–2010) are used to construct a long‐term data set from 1977 to 2010. Using this unprecedented data set, a decreasing trend of 2 m/s/yr is found, changing from strong eastward winds during the 1970s to weak westward winds in recent years. On the other hand, between 80 and 98 km using medium frequency radar observations during 1993–2009, no perceptible trend is found. Simulations of NCAR TIME‐GCM also showed a similar change in the circulation when CO 2 in the atmosphere is doubled, suggesting role of anthropogenic changes in the dynamics of the mesosphere.