evaporation : two u . s . weather bureau class a pans are operated at king s park . the mean water temperature is taken to be the mean of the daily maximum and minimum surface water temperature 蒸發(fā):天文臺(tái)使用兩個(gè)美國(guó)氣象局甲級(jí)蒸發(fā)皿于京士柏氣象站量度蒸發(fā)量,以皿內(nèi)每日量得的最高及最低水面溫度之平均數(shù)作為當(dāng)日的平均水溫。