地表温度分布定义——即 定义随时间变化的热流——太阳辐射（第二类边界条件） 定义随时间变化的外界温度——气温（第三条件）-The definition of surface temperature distribution- that is the definition of heat flow changes with time- solar radiation (the second boundary condition) is defined over time the outside temperature- air temperature (third condition)