Scale-size calculations, energy dissipation rates and height coverage of a 404 MHz wind profiler at IMD, Pune

• Published in: Current science (Bangalore) Vol. 96; no. 9; pp. 1176 - 1181
• Main Authors: Joshi, R. R., Singh, Narendra, Damle, S. H., Pant, G. B.
• Format: Journal Article
• Language: English
• Published: Current Science Association 10.05.2009
• Subjects: Energy dissipation; Kinematics; Light beams; Radar; Radial velocity; Spectral methods; TECHNICAL NOTE; Turbulence; Viscosity; Wavelengths; Wind; India, Maharashtra, Pune; India
• ISSN: 0011-3891

The 404 MHz wind profiler at the India Meteorological Department, Pune, is the first wind profiler of this frequency in India. Therefore, it is necessary to achieve maximum possible height to get valuable data. UHF wind profilers have better height and time resolution, which enables us to make reliable and correct estimations of the wind at various altitudes at regular spacing above the observational site. The height coverage of the profiler depends upon various factors like power aperture product and the operating wavelength via-a-vis scale sizes available in the atmosphere. In this study, daily averaged second moment data archived during clear-air conditions have been used to estimate the scale-size parameters in terms of eddy dissipation rates, which explicitly indicates that more height coverage of a profiler depends only on the availability of the scale sizes in the atmosphere to which the radar is sensitive, and that in turn depends on where in the inertial subrange the operating wavelength resides. Power aperture product at various ${\mathrm{C}}_{\mathrm{n}}^{2}$ values has been estimated. This note explicitly explains why the height coverage of the wind profiler at Pune is limited to 6–8 km under clear-air conditions.