RADIAT VARIABLES

D(k,j):   Fraction of downward diffuse radiation in total radiation
          above the canopy in wavelength band k and layer j.

U(k,j):   Fraction of upward diffuse radiation in total radiation
          above the canopy in wavelength band k and layer j.

DSTRAD (k,i,j):  Total radiation incident in layer j and angle class
                 j of wavelength k (diffuse+direct beam).

FRAREA (i,j):    Fraction of leaf area of angle class i in sunlit
                 area of layer j (FRAREA of one layer add up to SUNLIT).

FR(i):      Fraction of LAI in angle class i in LAI of one layer.
            A spherical distribution is assumed.

TBEAM(j):   Fraction of direct beam in direct beam above the canopy 
            passing through layer j.

FBEAM(k):   Fraction of direct beam radiation of wavelengths k in total
            radiation of those wavelengths above canopy (horiz.sensor).

SUP(j):     Fraction of upward diffuse radiation in total radiation above
            the canopy that originated in that layer from direct beam
            interception.

SDN(j):     Fraction of downward diffuse radiation in total radiation 
            above the canopy that originated in that layer from
            direct beam interception.

TLAYER:     Transmittance factor of one layer.

RLAYER:     Reflectance factor of one layer.

DOWN:       Fraction of downward diffuse radiation into one layer in total
            radiation above the canopy for that wavelength band (used in 
            convergence).

UP:         Fraction of upward diffuse radiation into one layer in total
            radiation above the canopy for that wavelength band (used in 
            convergence).

SUNLIT:     LAI of a layer that is sunlit.

BEAM(k):    Flux density of direct beam of wavelengths in a plane
            perpendicular to incident sunlight.

RADABV(k):  Total radiation flux density above the canopy in 
            wavelength band k.

BMFLX(k,j): Direct beam flux density incident in layer j of
            wavelength band k.

CT(i):      Fraction of beam flux density into angle class i in beam flux
            as would be measured perpendicular to the incidence angle.

ITOT:       Number of angle classes.

ITOTP1:     Index number for all values averaged over all angle classes
            in a layer.

DSTRAD(k,ITOTP1,J):   Average total radiation flux density over all leaf
                      angle classes incident in layer j of wavelength k.

EMIS:       Thermal emissivity of leaf.

SIGMA:      Constant used in calculation of blackbody radiation.

TEMPLF(ITOTP1,j):  Average leaf temperature over all angle classes
                   in layer j.

TEMPLF(i,j): Leaf temperature in angle class i and layer j.

KSTRT:      Index indicating if IHR before or after sunrise/sunset:
            (=3 for daytime and =1 for nighttime).

TSFC:       Soil surface temperature.

ESOIL:      Soil thermal radiation flux density

CLAI(j):    Cumulative LAI in layer j.

RNLAM(k,j): Net radiation flux density into layer j of wavelength k
            diffuse and direct beam.  (+) downward.

RNET(j):    Net total radiation flux density into layer j of all
            wavelengths.

RNDIV(j):   Net total radiation flux density of all wavelengths
            lost in layer j.

DSTNET(i,j):  Net total radiation of all wavelengths into layer j
              and angle class i.

ALEAF:      Leaf absorption factor.

PRAREA:     FAREA in percent.

SHADE(k,j): Fraction of LAI of LAI of layer j that is shaded from
            wavelength band k.

DAVE(k,j):  Average downward flux density from layer j in wavelength
            band k.

FRAREA(ITOTP1,j):  Shaded LAI of layer j

SOURCE

EMIS:       Thermal emissivity of leaf

EMISOL:     Thermal emissivity of soil