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Wind profiler observations of a monsoon low-level jet over a tropical Indian station

Kalapureddy, MCR and Rao, DN and Jain, AR and Ohno, Y (2007) Wind profiler observations of a monsoon low-level jet over a tropical Indian station. Annales Geophysicae, 25 (10). pp. 2125-2137.

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Abstract

Three-year high-resolution wind observations of the wind profiler have been utilized to characterize the diurnal and seasonal features of the monsoon Low-Level Jet (LLJ) over a tropical station, Gadanki (13.5° N, 79.2° E), with a focus on the diurnal variability of low-level winds. The Boreal summer monsoon winds show a conspicuously strong westerly LLJ with average wind speed exceeding 20 m s−1. The L-band wind profiler measurements have shown an advantage of better height and time resolutions over the conventional radiosonde method for diurnal wind measurements. An interesting diurnal oscillation of LLJ core has been observed. It is varying in the height range of 1.8±0.6 km with the maximum and minimum intensity noticed during the early morning and afternoon hours, respectively. The jet core (wind maxima) height is observed to coincide with the inversion height. Strong wind shears are normally located beneath the LLJ core. The sole wind profiler observations are capable of identifying the monsoon phases, such as onset, break and active spells, etc. The mutual influence between the LLJ and the boundary layer has been discussed. One notices that the observed LLJ diurnal structures depend on the local convective activity, wind shears and turbulence activity associated with boundary layer winds. The day-to-day change in the LLJ structure depends on the latitudinal position of the LLJ core.

Item Type: Article
Additional Information: Copyright of this article belongs to European Geosciences Union
Uncontrolled Keywords: boundary layer; diurnal variation; monsoon; observational method; radiosonde; tropical environment; wind measurement; wind shear; wind velocity, Asia; Eurasia; Gadanki; India; South Asia; Tamil Nadu
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 22 Feb 2015 06:43
Last Modified: 22 Feb 2015 06:43
URI: http://moeseprints.incois.gov.in/id/eprint/1872

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