RADIN4 VARIABLES

AVERAD:  Total visible radiation measured with a horizontal sensor above
         the canopy. Identical with RADSOL and RADTOP(2,IHR) in MAIN.

AIRMAS:  A measure of the pathway length that solar radiation travels
         through the atmosphere.

POTBM1:  Potential direct beam visible radiation at the earth's surface.

POTDIF:  Potential diffuse visible radiation at the earth's surface.

POTVIS:  Potential total visible radiation at the earth's surface.

POTBM2:  Potential direct beam NIR radiation at the earth's surface.

WATABS:  Solar NIR radiation absorbed by atmospheric water.

EVAL:    Potential diffuse NIR radiation at the earth's surface.

POTNIR:  Potential total NIR radiation at the earth's surface.

RATIO:   Ratio of actual total NIR radiation over the potential
         total visible and NIR radiation.

RADABV(1,IHR):  Ratio of the actual total visible radiation over
                the potential total visible radiation.

RADABV(2,IHR):  Ratio of the actual total NIR radiation over the
                potential total NIR radiation.

IPOT:    Index indicating method of calculation for RATIO(IHR),=1: fixed
         input of RATION and RATIOD,=0: calc in RADIN4 for every hour.

RATIOD:  Input variable for the ratio of actual total radiation
         in the NIR over the potential total visible and NIR radiation
         during the day.

RATION:  Input variable for the ratio of actual total NIR radiation over
         potential total radiation during the night.

FB1:     Ratio of potential direct beam visible radiation over
         potential total visible radiation.

FB2:     Ratio of potential direct beam NIR radiation over the
         potential total NIR radiation.

FBEAM1(1,IHR):  Ratio of the actual direct beam visible radiation
                over the actual total visible radiation.

FBEAM1(2,IHR):  Ratio of the actual direct beam NIR radiation 
                over the total NIR radiation.