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subroutine da_epsalt_tl(f,t,ssw,epsr,epsi,TGL_t, TGL_epsr, TGL_epsi) 1,2
!-----------------------------------------------------------------------
! Purpose: returns the complex dielectric constant of sea water, using the
! model of Klein and Swift (1977)
!
! Input f = frequency (GHz)
! t = temperature (C)
! ssw = salinity (permil) (if ssw < 0, ssw = 32.54)
! Output epsr,epsi = real and imaginary parts of dielectric constant
! Input : TGL_t (ssw is treated as a constant now)
! Output : TGL_epsr, TGL_epsi, epsr, epsi
!-----------------------------------------------------------------------
implicit none
real, intent(in) :: f, t, TGL_t
real, intent(inout) :: ssw
real, intent(out) :: TGL_epsr, TGL_epsi, epsr, epsi
complex :: cdum1,cdum2,cdum3
complex :: TGL_cdum1,TGL_cdum2,TGL_cdum3
real :: ssw2,ssw3,t2,t3,es,a,esnew,tau,b,sig,taunew
real :: delt,delt2,beta,signew,om
real :: TGL_t2,TGL_t3,TGL_es,TGL_a,TGL_esnew,TGL_tau,TGL_b,TGL_taunew
real :: TGL_delt,TGL_delt2,TGL_beta,TGL_signew
if (trace_use) call da_trace_entry
("da_epsalt_tl")
if (ssw .lt. 0.0) ssw = 32.54
ssw2 = ssw*ssw
ssw3 = ssw2*ssw
t2 = t*t
TGL_t2 = 2.0*t*TGL_t
t3 = t2*t
TGL_t3 = TGL_t2*t + t2*TGL_t
es = 87.134 - 1.949e-1*t - 1.276e-2*t2 + 2.491e-4*t3
TGL_es = - 1.949e-1*TGL_t - 1.276e-2*TGL_t2 + 2.491e-4*TGL_t3
a = 1.0 + 1.613e-5*ssw*t - 3.656e-3*ssw + 3.21e-5*ssw2 - &
4.232e-7*ssw3
TGL_a = 1.613e-5*ssw*TGL_t
esnew = es*a
TGL_esnew = TGL_es*a + es*TGL_a
tau = 1.768e-11 - 6.086e-13*t + 1.104e-14*t2 - 8.111e-17*t3
TGL_tau = - 6.086e-13*TGL_t + 1.104e-14*TGL_t2 - 8.111e-17*TGL_t3
b = 1.0 + 2.282e-5*ssw*t - 7.638e-4*ssw - 7.760e-6*ssw2 + &
1.105e-8*ssw3
TGL_b = 2.282e-5*ssw*TGL_t
taunew = tau*b
TGL_taunew = TGL_tau*b + tau*TGL_b
sig = ssw*(0.182521 - 1.46192e-3*ssw + 2.09324e-5*ssw2 - &
1.28205e-7*ssw3)
delt = 25.0 - t
TGL_delt = - TGL_t
delt2 = delt*delt
TGL_delt2 = 2.0*delt*TGL_delt
beta = 2.033e-2 + 1.266e-4*delt + 2.464e-6*delt2 &
- ssw*(1.849e-5 - 2.551e-7*delt + 2.551e-8*delt2)
TGL_beta = 1.266e-4*TGL_delt + 2.464e-6*TGL_delt2 &
- ssw*(-2.551e-7*TGL_delt + 2.551e-8*TGL_delt2)
signew = sig*exp(-beta*delt)
TGL_signew = - signew*(TGL_beta*delt+beta*TGL_delt)
om = 2.0e9*pi*f
cdum1 = cmplx(0.0,om*taunew)
TGL_cdum1 = cmplx(0.0,om*TGL_taunew)
cdum2 = cmplx(0.0,signew/(om*8.854e-12))
TGL_cdum2 = cmplx(0.0,TGL_signew/(om*8.854e-12))
cdum3 = 4.9 + (esnew-4.9)/(1.0 + cdum1) - cdum2
TGL_cdum3 = TGL_esnew/(1.0 + cdum1) &
- TGL_cdum1*(esnew-4.9)/((1.0 + cdum1)*(1.0 + cdum1)) &
- TGL_cdum2
epsr = real(cdum3)
TGL_epsr = real(TGL_cdum3)
epsi = -aimag(cdum3)
TGL_epsi = -aimag(TGL_cdum3)
if (trace_use) call da_trace_exit("da_epsalt_tl")
end subroutine da_epsalt_tl