_RL delta
delta = (hbl(i) + zgrid(ki)) / (zgrid(ki) - zgrid(ki+1))
dstar = (1.- delta)**2 * dkm1(i,md)
& + delta**2 * dkmp5
blmc(i,ki,md) = (1.- delta)*diffus(i,ki,md)
& + delta*dstar
_RL delta, deltaTile(nSx,nSy)
delta = 0. _d 0
delta = sumPhi(2,1,1)
alpha = delta - cgBeta**2*alpha
_RL dayfrac, yday, delta
delta = (0.006918 _d 0
sun1 = -sin(delta)/cos(delta) * sin(lat)/cos(lat)
cosz = ( sin(delta)*sin(lat)+ !average zenith angle
& (cos(delta)*cos(lat)*sin(dayhrs)/dayhrs) )