Mau..... (1982), 33, 2, 189·196

551.55: 551.524(54 1.3)

Windchill at LehA. K. MUKHERJEE and T. RAMANA RAO

Meteorological Office, Pune(Received 14 November 1980)

Ill1: - '" '"" 'R'I, f.f;liT fill 'lll_.m'R'l~~.q~ 'Ifm.q 'll't t I t'l >il"Il'm if~ om oil~r JfISlIll'p:ffii"it 3S14>1to oiI~l(" 34° 09' ...mr .m 77 0 34' ~iff\'lo~ R>R ~ "" '" """'l'I'f oil 'l'RT.q 'rH 1~ 'l'f"{ 'll'ITfut 'l'< W'ld14" '" , f;riI S f.!;0 >It 0 mn~ ,.-;rit~ 'IT'I'f '" "'" mn~ "l'l'"fiI;lrr'IT ..-..aT t,1!Rr <WI '" ""AT '"'l Wm oilm;r.q 'l'RT .q "ta1 J 9 S8 it t 9 6 8"'" (1!rof ""'" r.".." fiI'IT'I rm~d) oil t,...t.q.m;, '" af.rl; '""'t 1m( 'lll i .m <rftmt" .m~ _ 'li1'I'T'l1iI oil'1"1'11 .q 'l{ ~ 1 t'lilFe'" F~F..d """"" f.A;A 'l1!t :

( r)~ <rftmt" _ <rnr ii <T<-<T<~~.m~ift'loi\lfli<rrnIT~~ ~ I

( 2)~~ d1'l1!t'I <rnr if "'" 0In:-<r<~~ 1~~ 'llilmdT 'I'l"'rtlii~ t I

( 3 )~ "" 4furTor~ _ <rnr if WlOllF<l~~~ I

( 4) 'R'I.m _ ""'"~a1 t'l """'I~" lffiI4T >ftd>rnq- m- if~ if~ oil"'Ifu ;rtf fffit~ I

( s) <rftmt"~ I 4 mil 110 ~ 41111 'l4T 1

(6)~~ ii, <rftmt" ~..-.1i:m 'l'I'f rnT.m~~.m;,_ mr~ &<it ~ I

ABSTRACT . Windchil l. a measure of cooling power of atmosphere for any given condition oftemperature and wind, has been calculated for the mountain station Leh, situated in the Himalayan

mountain range located at an altitude of 3514 m above mean sea level at Lat. 34 d eg, 09' andLong. 71 deg, 34'. Dared on this en equivalent temperature; which would be felt on exposed humanbody in a S kmph wind - the amount of ventilation in an otherwise calm co ndition, has beencalculated. '[be daily data for eleven year period of 1958 to 1968 (collected by India Met Dep ) weretak en anJ calculations have been done for maximum and minimum temperature epochs. The followingconclusions have been arrived at:

( J) Windchill is more frequent in maximum temperature epoc h with highest frequency inOctober.

(2) Windchill is less frequent in minimum temperature epoch with least frequency in January.

(l) Magnitude of windchill is greater in the minimum temperature epoch.

(4) Wind and temperature are independent so that there is no tendency to increase windchillon coldest month or on the coldest day.

(5) Maximum windchill was found to be 14 deg, C.

(6 ) In the annual variat ion, the coldes t windchill periods are controlled by wind and the leastwindchill period by temperature.

1. Introduction

Windcbill is an important aspect of Biorneteoro­logy. It is known tbat temperature alone wouldnot indicate as to bow cold ODe might Feel and manyother environmental factors are involved, Parti­cularly important witb regard to this aspect is thewind Factor which influences the buman body byalterin g its beat-transfer to environment and also itsrate of evaporative cooling, A measure of the

cooling power of tbe atmo sphere for aDY giventemperature and wind conditions was given bySiple and Passel (1945) after a number of experi­ments,The relation given by them is :

K =(1O.45 + lOy>- v)(33 - T.) (I)

where, K is the cooling power (kilocal m- 2 hr'), vis the wind speed (m Sec-I) and T. is the ambientair temperature (0C) UDder conditions of calm

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