Seasonal, annual and inter-annual features of turbulence parameters over the tropical station Pune (18°32' N, 73°51' E) observed with UHF wind profiler

摘要

The present study is specifically focused on the seasonal, annual andinter-annual variations of the refractive index structure parameter (C_n2)using three years of radar observations. Energy dissipation rates(ε) during different seasons for a particular year are alsocomputed over a tropical station, Pune. Doppler spectral width measurementsmade by the Wind Profiler, under various atmospheric conditions, areutilized to estimate the turbulence parameters. The refractive indexstructure parameter varies from 10−17.5 to 10−13 m−2/3 underclear air to precipitation conditions in the height region of 1.05 to 10.35 km.During the monsoon months, observed C_n2 values are up to 1–2 ordersof magnitude higher than those during pre-monsoon and post-monsoon seasons.Spectral width correction for various non-turbulent spectral broadeningssuch as beam broadening and shear broadening are made in the observedspectral width for reliable estimation of ε undernon-precipitating conditions. It is found that in the lower troposphericheight region, values of ε are in the range of 10−6 to10−3 m2 s−3. In summer and monsoon seasons the observedvalues of ε are larger than those in post-monsoon and winterseasons in the lower troposphere. A comparison of C_n2 observed with thewind profiler and that estimated using Radio Sonde/Radio Wind (RS/RW) dataof nearby Met station Chikalthana has been made for the month of July 2003.