The PrecipAreaFrac needs to be updated when there is sprinkler irrigation water intercepted by crop canopy but no rain. CUrrently, PrecipAreaFrac will be zero for no rain days even there is sprinkler irrigation, which leads to zero intercepted water by crop canopy for sprinkler irrigation.
https://github.com/NCAR/noahmp/blob/fa2d2098bac1e437a21ccc15494b152996d5bc84/src/CanopyWaterInterceptMod.F90#L86C60-L86C74
The PrecipAreaFrac needs to be updated when there is sprinkler irrigation water intercepted by crop canopy but no rain. CUrrently, PrecipAreaFrac will be zero for no rain days even there is sprinkler irrigation, which leads to zero intercepted water by crop canopy for sprinkler irrigation.