%0 Journal Article
%T Coastal Boundary Layer Characteristics of Wind, Turbulence, and Surface Roughness Parameter over the Thumba Equatorial Rocket Launching Station, India
%A K. V. S. Namboodiri
%A Dileep Puthillam Krishnan
%A Rahul Karunakaran Nileshwar
%A Koshy Mammen
%A Nadimpally Kiran kumar
%J Journal of Climatology
%D 2014
%R 10.1155/2014/504178
%X The study discusses the features of wind, turbulence, and surface roughness parameter over the coastal boundary layer of the Peninsular Indian Station, Thumba Equatorial Rocket Launching Station (TERLS). Every 5£¿min measurements from an ultrasonic anemometer at 3.3£¿m agl from May 2007 to December 2012 are used for this work. Symmetries in mesoscale turbulence, stress off-wind angle computations, structure of scalar wind, resultant wind direction, momentum flux ( ), Obukhov length ( ), frictional velocity ( ), w-component, turbulent heat flux ( ), drag coefficient ( ), turbulent intensities, standard deviation of wind directions ( ), wind steadiness factor- relationship, bivariate normal distribution (BND) wind model, surface roughness parameter ( ), and wind direction ( ) relationship, and variation of with the Indian South West monsoon activity are discussed. 1. Introduction The lowest layers of the earth¡¯s atmosphere based on wind variation with height are categorized into different layers such as (1) laminar sublayer, (2) Prandtl layer, and (3) Ekman spiral layer. (1) and (2) are together called surface boundary layer (SBL) or surface layer (SL) or the tower layer or constant flux layer. SBL studies can find applications in wind power meteorology, aviation meteorology, aerospace meteorology, structural loading, air pollution, flow modeling, biometeorology, and weather forecast models. In the SBL, more specifically in Prandtl layer, the eddy stress (due to turbulence) is an order of magnitude larger than the horizontal pressure gradient force. Several approximations are available regarding SBL [1¨C3] about the height, vertical stress, heat flux, wind direction, turbulent diffusion, and insignificance of Coriolis effect. In a diabatic (nonadiabatic) atmosphere, the thermodynamic change of the state of the system is one in which there is transfer of heat across the boundaries of the system [4]. A general formula for the diabatic (nonadiabatic) wind profile in the SBL can be derived [3, 5] which provides the height above the earth¡¯s surface where the mean wind speed ( ) vanishes before the surface is called as the surface roughness parameter ( ): where is the wind measuring level, is the universal function of height relative to the Monin-Obukhov (MO) similarity theory [6], is the frictional velocity, is the von Karman constant ( 0.4), and is the Obukhov length. To determine the surface roughness parameter, stability corrected method proposed by Paulson [7] is used. The stability corrected Businger [5] method uses constants 4.7 and 15 instead of 5 and 16
%U http://www.hindawi.com/journals/jcli/2014/504178/