Skip to content

Implement MPAS init-atmosphere case 11 + 12 for model-level IFS and ERA5 with lapse-rate vinterp #1413

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
mrixlam wants to merge 6 commits into
base: develop
Choose a base branch
from
Open

Implement MPAS init-atmosphere case 11 + 12 for model-level IFS and ERA5 with lapse-rate vinterp #1413

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
fa48c91
Fix lapse-rate vinterp for EC
Feb 12, 2026
a2fd267
bugfix vinterp
mrixlam Apr 29, 2026
86845cb
Merge branch 'develop' into bugfix-vinterp-lapse-rate
mrixlam Apr 29, 2026
924b456
Add function for least square slope estimation
mrixlam Apr 29, 2026
ef43c50
Merge branch 'bugfix-vinterp-lapse-rate' of https://github.com/mrixla…
mrixlam Apr 29, 2026
34306d3
Add ECMWF model level initialization
mrixlam May 3, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 5 additions & 3 deletions src/core_init_atmosphere/mpas_init_atm_cases.F
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6882,6 +6882,7 @@ real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surf
integer :: k, lm, lp
real (kind=RKIND) :: wm, wp
real (kind=RKIND) :: slope
real (kind=RKIND) :: lapse_rate

integer :: interp_order, extrap_type
real (kind=RKIND) :: surface, sealevel
Expand Down Expand Up @@ -6933,9 +6934,9 @@ real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surf
slope = (zf(2,nz) - zf(2,nz-1)) / (zf(1,nz) - zf(1,nz-1))
vertical_interp = zf(2,nz) + slope * (target_z - zf(1,nz))
else if (extrap_type == 2) then
call mpas_log_write('extrap_type == 2 not implemented for target_z >= zf(1,nz)', messageType=MPAS_LOG_ERR)
if (present(ierr)) ierr = 1
return
! Lapse-rate extrapolation: calculate lapse rate from top two levels
lapse_rate = (zf(2,nz) - zf(2,nz-1)) / (zf(1,nz) - zf(1,nz-1))
vertical_interp = zf(2,nz) + lapse_rate * (target_z - zf(1,nz))
Copy link

Copilot AI Feb 12, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

For extrap_type == 2 (lapse-rate) at the upper boundary, this change computes lapse_rate from the top two levels, which makes it effectively the same as extrap_type == 1 linear extrapolation. In this same function, the lower-boundary lapse-rate branch uses a fixed 0.0065 K/m (line 6926), so the upper and lower implementations are now inconsistent. Please align the two (either both fixed-lapse-rate or both gradient-derived) and ensure linear vs lapse-rate remain meaningfully different options.

Suggested change
! Lapse-rate extrapolation: calculate lapse rate from top two levels
lapse_rate = (zf(2,nz) - zf(2,nz-1)) / (zf(1,nz) - zf(1,nz-1))
vertical_interp = zf(2,nz) + lapse_rate * (target_z - zf(1,nz))
! Lapse-rate extrapolation: use fixed lapse rate (0.0065 K/m)
vertical_interp = zf(2,nz) - (target_z - zf(1,nz))*0.0065

Copilot uses AI. Check for mistakes.
end if
return
end if
Expand Down Expand Up @@ -7522,3 +7523,4 @@ end function read_text_array


end module init_atm_cases

24 changes: 23 additions & 1 deletion src/core_init_atmosphere/mpas_init_atm_vinterp.F
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ module init_atm_vinterp
!
! Purpose:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surface_val, sealev_val)
real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surface_val, sealev_val, ierr)

implicit none

Expand All @@ -33,10 +33,12 @@ real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surf
integer, intent(in), optional :: extrap
real (kind=RKIND), intent(in), optional :: surface_val
real (kind=RKIND), intent(in), optional :: sealev_val
integer, intent(out), optional :: ierr ! error code: 0 = success, 1 = invalid extrapolation type

integer :: k, lm, lp
real (kind=RKIND) :: wm, wp
real (kind=RKIND) :: slope
real (kind=RKIND) :: lapse_rate

integer :: interp_order, extrap_type
real (kind=RKIND) :: surface, sealevel
Expand Down Expand Up @@ -66,6 +68,11 @@ real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surf
sealevel = 201300.0
end if

! Initialize ierr to 0 (success)
if (present(ierr)) then
ierr = 0
end if

!
! Extrapolation required
!
Expand All @@ -75,6 +82,13 @@ real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surf
else if (extrap_type == 1) then
slope = (zf(2,2) - zf(2,1)) / (zf(1,2) - zf(1,1))
vertical_interp = zf(2,1) + slope * (target_z - zf(1,1))
else if (extrap_type == 2) then
! Lapse-rate extrapolation: calculate lapse rate from bottom two levels
lapse_rate = (zf(2,2) - zf(2,1)) / (zf(1,2) - zf(1,1))
vertical_interp = zf(2,1) + lapse_rate * (target_z - zf(1,1))
Copy link

Copilot AI Feb 12, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

extrap_type == 2 (lapse-rate) is implemented here using the same formula as extrap_type == 1 (linear), i.e., a slope computed from the bottom two levels. That makes the new lapse-rate option behaviorally identical to linear extrapolation. If lapse-rate is intended to be a fixed temperature lapse rate (as in the other vertical_interp implementation in mpas_init_atm_cases.F), please apply that constant lapse rate here (or otherwise document/rename the option so it’s not indistinguishable from linear).

Copilot uses AI. Check for mistakes.
else
vertical_interp = zf(2,1)
if (present(ierr)) ierr = 1
end if
Comment on lines 84 to 88
Copy link

Copilot AI Apr 29, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The PR description focuses on adding missing upper-boundary support for extrap_type==2, but this diff also changes the lower-boundary extrap_type==2 behavior from a fixed 0.0065 K/m to a least-squares fitted slope from the lowest levels. Please update the PR description (and any user-facing docs for config_extrap_airtemp='lapse-rate') to reflect this broader behavior change.

Copilot uses AI. Check for mistakes.
return
end if
Expand All @@ -84,6 +98,13 @@ real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surf
else if (extrap_type == 1) then
slope = (zf(2,nz) - zf(2,nz-1)) / (zf(1,nz) - zf(1,nz-1))
vertical_interp = zf(2,nz) + slope * (target_z - zf(1,nz))
Comment on lines 78 to 96
Copy link

Copilot AI Apr 29, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

In the extrapolation branches, the linear extrapolation path assumes nz >= 2 (accesses zf(:,2) / zf(:,nz-1)). If the caller provides only a single vertical level (e.g., nz==1), this becomes an out-of-bounds access. Please add an explicit nz < 2 fallback (e.g., treat as constant extrapolation and/or set ierr + log an error) before computing the slope for extrap_type == 1.

Copilot uses AI. Check for mistakes.
else if (extrap_type == 2) then
! Lapse-rate extrapolation: calculate lapse rate from top two levels
lapse_rate = (zf(2,nz) - zf(2,nz-1)) / (zf(1,nz) - zf(1,nz-1))
vertical_interp = zf(2,nz) + lapse_rate * (target_z - zf(1,nz))
Copy link

Copilot AI Feb 12, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Upper-boundary extrap_type == 2 uses a lapse rate computed from the top two levels, which is mathematically equivalent to the existing extrap_type == 1 linear extrapolation. If lapse-rate is meant to behave differently from linear (e.g., fixed -6.5 K/km), this should be adjusted so the two extrapolation modes are not duplicates.

Copilot uses AI. Check for mistakes.
else
vertical_interp = zf(2,nz)
if (present(ierr)) ierr = 1
end if
Comment on lines +78 to 101
Copy link

Copilot AI Apr 29, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The extrapolation if/else if chain has no final else to handle unexpected extrap_type values. If a caller passes something other than {0,1,2}, vertical_interp can be returned uninitialized while ierr remains 0. Please add a default branch that logs an error and sets ierr (and/or falls back to constant extrapolation).

Copilot uses AI. Check for mistakes.
return
end if
Expand All @@ -109,3 +130,4 @@ real (kind=RKIND) function vertical_interp(target_z, nz, zf, order, extrap, surf
end function vertical_interp

end module init_atm_vinterp

Loading