On the optimum time of integration for estimation of momentum flux from VHF radar data

[1] VHF radar at Gadanki (13.5°N, 79.2°E) was operated continuously for 24 hours to obtain a unique set of high resolution (150 m in height and 2.5 min. in time) wind data in the troposphere and lower stratosphere. This high quality wind data have been used to estimate momentum flux of short period (<2 hr) wind fluctuations and the associated uncertainties. Error analysis has been carried out by varying the length of integration time. We show that an optimal time of averaging of about 15–16 hrs minimizes the error at a value nearly equal to the irreducible error observed by an ideal anemometer measuring u, v and w at a point.