With FAO irrigation and drainage series books 56th part Penman-Monteith formula, computation program of ET0 had been developed about day and month as time unit, and ET value would be known while giving crop coefficient Kc.

• 运用FAO灌溉排水丛书第56 分册提供的Penman-Monteith公式,编制了以日和月为时间单位的计算ET0 程序,通过调用Kc参数表,可计算出ET;