Laserfiche WebLink
<br />Where IIOre detailed infonnation is available. a nUlllber of energy- <br />budget relationships can be used. Particularly useful are the following <br />two sfmp1ified relationships: <br />M . 2.3C2 + C2 (1.33 + .51W + .013R) (T - TO) (2) <br /> <br />M . O.5C3S(1 - A) + C3(.11W + 6.6) (T - TO) + .4OW(D-TO) (3) <br /> <br />in which: <br />C2 . Calibration constant <br /> <br />C3 . Calibration constant <br /> <br />W . Wind speed in llIl!ters per second 15 .eters above the <br />snow surface <br />R . Rainfall milliMeters <br />S . Solar radiation in 1angl81s <br />D · Dewpoint in degrees centigrade <br /> <br />Precipitation that occurs during the snowmelt season occurs as <br />snowfall and is added to the snowpack when and where temperatures are <br />below 1 or 2 degrees centigrade. Otherwise it occurs as rain and is <br />absorbed by the snowpack until saturation and melting temperatures are <br />reached and the excess is added to the snowmelt for that computation <br />i nterva 1 . <br />Temperature sequences that Might be used in the computation of <br />hypothetical snCMllelt floods are very difficult to derive. because <br />critical condftions are not usually related to ..ximum temperatures <br />throughout the melt season. Often the most critical conditions are <br />those where early temperatures remain low in order to preserve the <br />snowpack l.IItil the season of higher teIlperature potential. Maximum <br />temperatures for various durations at any particular time of year can <br />be derived through frequency studies of temperatures recorded at that <br />time each year. These temperatures are a function of elevation. <br />Critical temperature sequences should not exceed ..ximum selected <br />amounts for any specified time of year. and can be derived through a <br /> <br />2-13 <br />