! source file: /Users/nadinemengis/Documents/UVic_ESCM/2.10/source/mom/bcest.F
subroutine bcest (tlat, ulat, bcval)
!=======================================================================
! this routine linearly interpolates global, zonal mean values of
! ocean model surface boundary conditions (SST, salinity, WSX, WSY)
! having 4.5 deg spacing, to the requested latitude.
!=======================================================================
implicit none
integer nbc, nolat, nolatp, n, nn, i
parameter (nbc=4, nolat=40, nolatp=nolat+1)
real c1, c0, p5, phione, phitwo, phithree, phifour, pi, radulat
real ulat, radtlat, tlat, dolat, rdolat, olatt, olatv, ylatt, d
real ylatv
parameter (c1=1.0, c0=0.0, p5=0.5)
common /cbcest/ olatt(nolat), olatv(nolatp), dolat, rdolat
real sstobs(nolat), salobs(nolat)
real wsxobs(nolatp), wsyobs(nolatp)
real bcval(nbc)
! bcval = estimated boundary condition values ( wsx, wsy,t,s)
! bcval(1) and bcval(2) units = dynes per square centimetre
! bcval(3) units = degrees C
! bcval(4) units = parts per thousand
! nbc = number of boundary conditions
! olatt = latitude points for observed data
! olatv = latitude points for observed data
! dolat = latitude spacing for observed data
! ylatt = latitude where t,s boundary conditions are desired
! ylatv = latitude where windstress boundary conditions are desired
! "observed" temperature and salinity data are based on global,
! annual mean zonally averaged values from the Levitus Atlas (1982).
! "observed" windstress data are based on global, annual mean,
! zonally averaged values from Hellerman and Rosenstein (1981).
! some smoothing was done.
! references:
! Hellerman, S, and M. Rosenstein, normal monthly wind stress
! over the world ocean with error estimates, J. Phys, Oceanogr., 13,
! 1093-1104,1983.
! Levitus, S., Climatological atlas of the world ocean, NOAA
! Prof. Paper 13, US Gov`t printing Office, Washington, DC, 1982.
data sstobs / -1.75, -1.75, -1.50, -1.50, -1.28,
& -0.55, 0.90, 2.92, 5.45, 8.62,
& 12.27, 15.49, 18.30, 20.67, 22.64,
& 24.14, 25.27, 26.37, 26.52, 26.16,
& 26.85, 27.27, 26.82, 26.42, 25.53,
& 24.03, 22.07, 19.73, 17.02, 12.77,
& 8.93, 7.25, 6.22, 4.67, 4.57,
& 3.03, -0.01, -1.05, -1.75, -1.75/
data salobs / 34.30, 34.30, 34.30, 34.13, 33.98,
& 33.97, 33.97, 33.98, 34.03, 34.24,
& 34.61, 35.02, 35.37, 35.61, 35.72,
& 35.68, 35.51, 35.22, 35.05, 35.12,
& 34.80, 34.56, 34.71, 34.90, 35.27,
& 35.67, 35.56, 35.49, 35.23, 34.28,
& 33.57, 33.57, 33.60, 33.80, 34.04,
& 34.05, 32.65, 32.30, 32.10, 32.00/
data wsxobs / 0.00,
& 0.00, 0.00, -0.02, 0.15, 0.31,
& 0.50, 0.82, 1.08, 1.23, 1.16,
& 0.84, 0.41, 0.02, -0.35, -0.55,
& -0.67, -0.64, -0.46, -0.29, -0.19,
& -0.16, -0.33, -0.52, -0.59, -0.55,
& -0.32, 0.09, 0.42, 0.56, 0.76,
& 0.81, 0.65, 0.29, 0.06, -0.10,
& -0.05, -0.03, 0.05, 0.10, 0.01/
data wsyobs / .000,
& .000, .009, .032, .005, -.023,
& -.075, -.155, -.202, -.230, -.179,
& -.049, .093, .214, .294, .344,
& .383, .364, .269, .189, .178,
& .125, -.122, -.213, -.251, -.259,
& -.202, -.189, -.179, -.183, -.009,
& .023, .053, -.048, -.185, -.225,
& -.097, -.050, -.023, -.006, .000/
!---------------------------------------------------------------------
! set latitudes of sst and salinity observations
! and set latitudes of windstress observations
!---------------------------------------------------------------------
dolat = 180.0/nolat
rdolat = c1/dolat
do n=1,nolat
olatt(n) = -90.0 + (n-p5)*dolat
olatv(n) = -90.0 + (n-1.0)*dolat
enddo
olatv(nolatp) = -90.0 + (nolat)*dolat
!---------------------------------------------------------------------
! use linear interpolation to produce the estimated surface boundary
! condition values for temperature and salinity at t,s row j
!---------------------------------------------------------------------
ylatt = tlat
if (ylatt .le. olatt(1)) then
nn = 1
d = c0
elseif (ylatt .ge. olatt(nolat)) then
nn = nolat-1
d = dolat
else
do i=2,nolat
if (ylatt .le. olatt(i)) then
nn = i - 1
d = ylatt - olatt(nn)
goto 201
endif
enddo
endif
201 continue
bcval(3) = (sstobs(nn)*(dolat - d) + sstobs(nn+1)*d)*rdolat
bcval(4) = (salobs(nn)*(dolat - d) + salobs(nn+1)*d)*rdolat
!---------------------------------------------------------------------
! use linear interpolation to produce the estimated surface boundary
! condition values for wind stress components at u,v row j
!---------------------------------------------------------------------
ylatv = ulat
if (ylatv .le. olatv(1)) then
nn = 1
d = c0
elseif (ylatv .ge. olatv(nolatp)) then
nn = nolatp - 1
d = dolat
else
do i=2,nolatp
if (ylatv .le. olatv(i)) then
nn = i - 1
d = ylatv - olatv(nn)
goto 301
endif
enddo
endif
301 continue
bcval(1) = (wsxobs(nn)*(dolat - d) + wsxobs(nn+1)*d) *rdolat
bcval(2) = (wsyobs(nn)*(dolat - d) + wsyobs(nn+1)*d) *rdolat
return
end