Krishna Mohan Rao, M

Patnaik, J K

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Letters to the EditorInd'ktn J, Phys. 49, 63-64 (1975)Estimation o f condensation levels over VisakhapatnamM. K ktshna  M o han  R ao* and J. K. P a t n a ik  DepartmPMt of Meteorology and Oceanography, Andhra Universily, Waltair (Beceived 4 June 1974, revised 2 September 1974)WJion moi,st uneatAiratod air ascends adiabatically its temperature decreases. As the ascent proceeds, the air in question, will reach a temperature, at which ihe water vapour present is just sufficient to saturate the air. The height in the almosp]i,erp, at winch this occurs is known as the condensation level. This level (;an be computed from tli,e tephigram using Normands third proposition which states that the dry adiabat through the dry bulb ttmporature, the saturated arliabat through the wet-bulb temperature and the }\umidity mixing ratio line through the dew point intersect at a point. At this point of intersection con­densation begins.llewson & Longley (1951) have obtained an equation from thermodynamical means which is given asHH  =  125(TT-TD ) (1)Here H ff is the height of the condensation level in metres, TT  and TD are dry bull) temperature and dewpoint at the surface in degrees oentrigrade/absoluto, roHpoctivoly. This equation involves assumptions and approximations as such its validity is doubtful.In the present work a new equation is derived from statistical means for (istimating the height of condensation level in the atmosphere.This method involves in finding a relation, by the method of least squares, bcitwcen throe variables, HH  (height of condensation level), T T  (dry bulb tem­perature) and TD (dewpoint). The equation is given as,HH  =  P + Q TT+ R TD (2)Here P, Q and R are constants and their values are obtained by solving the normal equations.* Present address : Central Ground Water Board, Western Region, Jaipur.6364 M. Krishna Mohan Rao and J. K. PatnaikTho surface prossure, surface dry Imlb iomperaturo and surface dewpoint are noted for both the synoptic hoiu^s of each day for the months of June, July and August for fiv(^  years at Visakhapatnam.The dry bulb temperature and dewpoint are marked on the corresponding pressiue lino on t]i.e tephigram. dry adiabat through the dry bulb tem­perature and t]\G humidity mixing ration line iJu’ough the dewpoint intersect at a point and tJie lieight of the point of intersection is easily computed. For each set of observations th(^  corresponding heigJits are obtained. Thus a number (N) of sots of heigilts and tho corresjionding snri'acc temperatures are used to solve tlie throe normal ecpuitions for the tlu’eo constants.The values of th<i constants as obtained ar(^ ,3J5, 0 -^1 1 9  and -132 .Substituting th,eso values in eq. (3)H II =  335 f  119rT -132T Il ... (3)Here H ll  is lh(5 lieight of condiijisation level iji metres TT  and TV  arts surface dry bulb temptwaturt'. and smface dewpoint respectively in degrees centigrade/ absolute.Eq. (3) as obtained by the authors liy the method of least squares, ^ivos results eomparablt^ to those obtained from the ttqJiigrain quickly and easily.The authors are grateful to Prof. R. Ramanadham, Head of the Department of Meteorology and Oceanography, Andhra Univtu’sity, Waltair, and Project Manager, WMO/XMTR, Nairobi, Konya, for liis keen interest and constant guidance during the work.R e f e b e n o e sHew;=ioji B. W. & Loiigloy K. W. 19ril Meteorolor/y, Theoretical and Applied^ John Wiley &Sons, Inc., Now York.

Estimation of Condensation Levels over Visakhapatnam

http://arxiv.iacs.res.in:8080/jspui/bitstream/10821/6006/1/Estimation%20of%20condensation_J%20K%20Patnaik.pdf

Estimation of Condensation Levels over Visakhapatnam

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