Open AccessAnomalous Wind Circulation Observed during 1997/98 El Niño Using Indian MST Radar
Author(s) -
V. Ramgopal Rao,
A. Narendra Babu,
S. Vijaya Bhaskara Rao,
D. Narayana Rao
Publication year - 2007
Publication title -
journal of applied meteorology and climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.079
H-Index - 134
eISSN - 1558-8432
pISSN - 1558-8424
DOI - 10.1175/jam2443.1
Subject(s) - climatology , jet stream , stratosphere , atmospheric sciences , troposphere , hadley cell , atmospheric circulation , geology , circulation (fluid dynamics) , monsoon , zonal and meridional , jet (fluid) , general circulation model , climate change , physics , oceanography , thermodynamics
Unique facility of measuring vertical winds using Indian mesosphere–stratosphere–troposphere (MST) radar along with horizontal winds enables the study of the atmospheric circulation over Gadanki, India. Several important features are noted while analyzing the wind field. A tropical easterly jet stream of 35 m s−1 strength is seen around 16 km during monsoon season. Relatively strong jetlike northward motion (southerlies) of 5–7 m s−1 is seen around 14 km during winter months. These two maxima in zonal and meridional wind patterns, even though they differ in strength greatly, occur in two contrasting seasons. Downward motion combined with upper-level northward and lower-level southward motion observed during winter in normal years indicates the signature of tropical Hadley circulation over the study region. During the 1997/98 El Niño event, however, an anomalous pattern of winds is seen and Hadley circulation is observed to be weakened.