simplified code and allowed for TOA alt

photochem/cython/Atmosphere.pyx

@@ -518,9 +518,9 @@ cdef class Atmosphere:
     if len(err.strip()) > 0:
        raise PhotoException(err.decode("utf-8").strip())
 
-  def update_vertical_grid(self, double TOA_pressure):
+  def update_vertical_grid(self, TOA_alt = None, TOA_pressure = None):
     """Re-does the vertical grid so that the pressure at the top of the
-    atmosphere is at `TOA_pressure`. If the TOA needs to be raised above the current
+    atmosphere is at `TOA_alt` or `TOA_pressure`. If the TOA needs to be raised above the current
     TOA, then the function constantly extrapolates mixing ratios, temperature,
     eddy diffusion, and particle radii.
 
@@ -531,6 +531,19 @@ cdef class Atmosphere:
     """
     cdef char err[ERR_LEN+1]
 
-    a_pxd.atmosphere_update_vertical_grid_wrapper(&self._ptr, &TOA_pressure, err)
+    cdef double TOA_alt_ = 0.0
+    cdef bool TOA_alt_present = False
+    if TOA_alt != None:
+      TOA_alt_present = True
+      TOA_alt_ = TOA_alt
+
+    cdef double TOA_pressure_ = 0.0
+    cdef bool TOA_pressure_present = False
+    if TOA_pressure != None:
+      TOA_pressure_present = True
+      TOA_pressure_ = TOA_pressure
+
+    a_pxd.atmosphere_update_vertical_grid_wrapper(&self._ptr, &TOA_alt_, &TOA_alt_present, 
+                                                  &TOA_pressure_, &TOA_pressure_present, err)
     if len(err.strip()) > 0:
       raise PhotoException(err.decode("utf-8").strip())

photochem/cython/Atmosphere_pxd.pxd

@@ -49,4 +49,5 @@ cdef extern void atmosphere_set_temperature_wrapper(void *ptr, int *nz, double *
 
 cdef extern void atmosphere_set_rate_fcn_wrapper(void *ptr, char *species_c, time_dependent_rate_fcn fcn, char *err)
 
-cdef extern void atmosphere_update_vertical_grid_wrapper(void *ptr, double *toa_pressure, char *err)
+cdef extern void atmosphere_update_vertical_grid_wrapper(void *ptr, double *toa_alt, bool *toa_alt_present,
+                                                         double *toa_pressure, bool *toa_pressure_present, char *err)

photochem/fortran/Atmosphere_wrapper.f90

@@ -503,17 +503,30 @@ subroutine atmosphere_set_rate_fcn_wrapper(ptr, species_c, fcn_c, err) bind(c)
     endif 
   end subroutine
 
-  subroutine atmosphere_update_vertical_grid_wrapper(ptr, TOA_pressure, err) bind(c)
+  subroutine atmosphere_update_vertical_grid_wrapper(ptr, TOA_alt, TOA_alt_present, &
+                                                     TOA_pressure, TOA_pressure_present, err) bind(c)
     type(c_ptr), intent(in) :: ptr
+    real(c_double), intent(in) :: TOA_alt
+    logical(c_bool), intent(in) :: TOA_alt_present
     real(c_double), intent(in) :: TOA_pressure
+    logical(c_bool), intent(in) :: TOA_pressure_present
     character(kind=c_char), intent(out) :: err(err_len+1)
 
     character(:), allocatable :: err_f
     type(Atmosphere), pointer :: pc
 
     call c_f_pointer(ptr, pc)
 
-    call pc%update_vertical_grid(TOA_pressure, err_f)
+    if (TOA_alt_present .and. .not.TOA_pressure_present) then
+      call pc%update_vertical_grid(TOA_alt=TOA_alt, err=err_f)
+    elseif (.not.TOA_alt_present .and. TOA_pressure_present) then
+      call pc%update_vertical_grid(TOA_pressure=TOA_pressure, err=err_f)
+    elseif (TOA_alt_present .and. TOA_pressure_present) then
+      call pc%update_vertical_grid(TOA_alt=TOA_alt, TOA_pressure=TOA_pressure, err=err_f)
+    elseif (.not.TOA_alt_present .and. .not.TOA_pressure_present) then
+      call pc%update_vertical_grid(err=err_f)
+    endif
+
     err(1) = c_null_char
     if (allocated(err_f)) then
       call copy_string_ftoc(err_f, err)

src/atmosphere/photochem_atmosphere.f90

@@ -295,12 +295,13 @@ module subroutine set_rate_fcn(self, species, fcn, err)
     end subroutine
 
     !> Re-does the vertical grid so that the pressure at the top of the
-    !> atmosphere is at `TOA_pressure`. If the TOA needs to be raised above the current
+    !> atmosphere is a `TOA_alt` or `TOA_pressure`. If the TOA needs to be raised above the current
     !> TOA, then the function constantly extrapolates mixing ratios, temperature,
     !> eddy diffusion, and particle radii.
-    module subroutine update_vertical_grid(self, TOA_pressure, err)
+    module subroutine update_vertical_grid(self, TOA_alt, TOA_pressure, err)
       class(Atmosphere), target, intent(inout) :: self
-      real(dp), intent(in) :: TOA_pressure !! New top of atmosphere pressure (dynes/cm^2)
+      real(dp), optional, intent(in) :: TOA_alt !! New top of atmosphere altitude (cm)
+      real(dp), optional, intent(in) :: TOA_pressure !! New top of atmosphere pressure (dynes/cm^2)
       character(:), allocatable, intent(out) :: err
     end subroutine