Representative scales of LASPEX wind data

Abstract

In this study, an attempt is made to identify the appropriate scales for the wind data over the stations covered in the LASPEX experiment, which can be considered to represent the large-scale wind pattern, representative of the whole area, covered by the field experiment. The divergence field was chosen for this purpose. The mean of the latitudes and longitudes of all the five stations was calculated and this represented the latitude and longitude respectively, of the central point. The wind components at each of the five stations were arbitrarily represented by a trigonometric function of wavelength and distance from the central point, which was considered as the origin. The divergence values at each station were computed and the mean value over all the stations was found. The same values of winds were used to compute the large scale divergence field over the area, by applying the method devised by Yanai et al. (1973). It was seen that for wavelengths greater than 2830 km, the ratio of the two divergences was greater than 0.9, suggesting that this was the limiting value of the wavelength which can be considered as representative of the entire area.