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subroutine da_find_layer_tl(layer,tv,pre,pre_ma,tv_ma,ks,ke,TGL_tv,TGL_pre_ma,TGL_tv_ma) 2,2
!-----------------------------------------------------------------------
! Purpose: tangent-linear routine for da_find_layer
!-----------------------------------------------------------------------
implicit none
integer, intent(in) :: ks, ke
integer, intent(out) :: layer
real, intent(in) :: tv_ma(ks-1:ke+1)
real, intent(inout) :: pre_ma(ks-1:ke+1)
real, intent(in) :: TGL_tv_ma(ks-1:ke+1)
real, intent(inout) :: TGL_pre_ma(ks-1:ke+1)
real, intent(in) :: pre
real, intent(out) :: tv
real, intent(out) :: TGL_tv
real :: TGL_alpha
integer :: k
real :: alpha, coef1, coef2
if (trace_use_frequent) call da_trace_entry
("da_find_layer_tl")
! coef1, coef2 are temporarily used in this routine
if (pre >= pre_ma(ks)) then
! Below model bottom
layer = ks
coef1=log(pre/pre_ma(ks+1))/(pre_ma(ks)* &
(log(pre_ma(ks)/pre_ma(ks+1)))**2)
coef2=log(pre_ma(ks)/pre)/(pre_ma(ks+1)* &
(log(pre_ma(ks)/pre_ma(ks+1)))**2)
TGL_alpha = coef1 * TGL_pre_ma(ks) + coef2 * TGL_pre_ma(ks+1)
alpha = log(pre_ma(ks)/pre)/log(pre_ma(ks)/pre_ma(ks+1))
TGL_tv = (1.0-alpha)*TGL_tv_ma(ks) + &
(tv_ma(ks+1)-tv_ma(ks))*TGL_alpha + &
alpha*TGL_tv_ma(ks+1)
TGL_pre_ma(ks-1) = 0.0
tv = tv_ma(ks) * (1.0-alpha) + tv_ma(ks+1) * alpha
pre_ma(ks-1) = pre
else if (pre <= pre_ma(ke)) then
! Above model top
layer = ke+1
coef1=log(pre/pre_ma(ke))/(pre_ma(ke-1)* &
(log(pre_ma(ke-1)/pre_ma(ke)))**2)
coef2=log(pre_ma(ke-1)/pre)/(pre_ma(ke)* &
(log(pre_ma(ke-1)/pre_ma(ke)))**2)
TGL_alpha = coef1 * TGL_pre_ma(ke-1) + coef2 * TGL_pre_ma(ke)
alpha = log(pre_ma(ke-1)/pre)/log(pre_ma(ke-1)/pre_ma(ke))
TGL_tv = (1.0-alpha)*TGL_tv_ma(ke-1) + &
(tv_ma(ke)-tv_ma(ke-1))*TGL_alpha + &
alpha*TGL_tv_ma(ke)
TGL_pre_ma(ke+1) = 0.0
tv = tv_ma(ke-1) * (1.0-alpha) + tv_ma(ke) * alpha
pre_ma(ke+1) = pre
else
! Between model layers
do k=ks,ke-1
if (pre>=pre_ma(k+1) .and. pre<pre_ma(k)) then
layer = k+1
coef1=log(pre/pre_ma(k+1))/(pre_ma(k)* &
(log(pre_ma(k)/pre_ma(k+1)))**2)
coef2=log(pre_ma(k)/pre)/(pre_ma(k+1)* &
(log(pre_ma(k)/pre_ma(k+1)))**2)
TGL_alpha = coef1 * TGL_pre_ma(k) + coef2 * TGL_pre_ma(k+1)
alpha = log(pre_ma(k)/pre)/log(pre_ma(k)/pre_ma(k+1))
TGL_tv = (1.0-alpha)*TGL_tv_ma(k) + &
(tv_ma(k+1)-tv_ma(k))*TGL_alpha + &
alpha*TGL_tv_ma(k+1)
tv = tv_ma(k) * (1.0-alpha) + tv_ma(k+1) * alpha
exit
end if
end do
end if
if (trace_use_frequent) call da_trace_exit("da_find_layer_tl")
end subroutine da_find_layer_tl