! $Id$ module regr_lat_time_climoz_m ! Author: Lionel GUEZ implicit none private public regr_lat_time_climoz contains subroutine regr_lat_time_climoz(read_climoz) ! "regr_lat_time_climoz" stands for "regrid latitude time ! climatology ozone". ! This procedure reads a climatology of ozone from a NetCDF file, ! regrids it in latitude and time, and writes the regridded field ! to a new NetCDF file. ! The input field depends on time, pressure level and latitude. ! If the input field has missing values, they must be signaled by ! the "missing_value" attribute. ! We assume that the input field is a step function of latitude ! and that the input latitude coordinate gives the centers of steps. ! Regridding in latitude is made by averaging, with a cosine of ! latitude factor. ! The target LMDZ latitude grid is the "scalar" grid: "rlatu". ! The values of "rlatu" are taken to be the centers of intervals. ! We assume that in the input file: ! -- Latitude is in degrees. ! -- Latitude and pressure are strictly monotonic (as all NetCDF ! coordinate variables should be). ! -- The time coordinate is in ascending order (even though we do ! not use its values). ! The input file may contain either values for 12 months or values ! for 14 months. ! If there are 14 months then we assume that we have (in that order): ! December, January, February, ..., November, December, January ! -- Missing values are contiguous, at the bottom of ! the vertical domain and at the latitudinal boundaries. ! If values are all missing at a given latitude and date, then we ! replace those missing values by values at the closest latitude, ! equatorward, with valid values. ! Then, at each latitude and each date, the missing values are replaced ! by the lowest valid value above missing values. ! Regridding in time is by linear interpolation. ! Monthly values are processed to get daily values, on the basis ! of a 360-day calendar. ! If there are 14 months, we use the first December value to ! interpolate values between January 1st and mid-January. ! We use the last January value to interpolate values between ! mid-December and end of December. ! If there are only 12 months in the input file then we assume ! periodicity for interpolation at the beginning and at the end of the ! year. use mod_grid_phy_lmdz, ONLY : nbp_lat use regr1_conserv_m, only: regr1_conserv use regr3_lint_m, only: regr3_lint use netcdf95, only: handle_err, nf95_close, nf95_get_att, nf95_gw_var, & nf95_inq_dimid, nf95_inq_varid, nf95_inquire_dimension, nf95_open, & nf95_put_var use netcdf, only: nf90_get_att, nf90_get_var, nf90_noerr, nf90_nowrite use assert_m, only: assert use regular_lonlat_mod, only : boundslat_reg, south use nrtype, only: pi use slopes_m, only: slopes integer, intent(in):: read_climoz ! read ozone climatology ! Allowed values are 1 and 2 ! 1: read a single ozone climatology that will be used day and night ! 2: read two ozone climatologies, the average day and night ! climatology and the daylight climatology ! Variables local to the procedure: integer n_plev ! number of pressure levels in the input data integer n_lat ! number of latitudes in the input data integer n_month ! number of months in the input data real, pointer:: latitude(:) ! (of input data, converted to rad, sorted in strictly ascending order) real, allocatable:: sin_lat_in_edg(:) ! (sine of edges of latitude intervals for input data, in rad, in strictly ! ascending order) real, pointer:: plev(:) ! pressure levels of input data, sorted in strictly ascending ! order, converted to hPa logical desc_lat ! latitude in descending order in the input file logical desc_plev ! pressure levels in descending order in the input file real, allocatable:: o3_in(:, :, :, :) ! (n_lat, n_plev, n_month, read_climoz) ! ozone climatologies from the input file ! "o3_in(j, k, :, :)" is at latitude "latitude(j)" and pressure ! level "plev(k)". ! Third dimension is month index, first value may be December or January. ! "o3_in(:, :, :, 1)" is for the day- night average, "o3_in(:, :, :, 2)" ! is for daylight. real missing_value real, allocatable:: o3_regr_lat(:, :, :, :) ! (nbp_lat, n_plev, 0:13, read_climoz) ! mean of "o3_in" over a latitude interval of LMDZ ! First dimension is latitude interval. ! The latitude interval for "o3_regr_lat(j,:, :, :)" contains "rlatu(j)". ! If "j" is between 2 and "nbp_lat - 1" then the interval is: ! [rlatv(j), rlatv(j-1)] ! If "j" is 1 or "nbp_lat" then the interval is: ! [rlatv(1), pi / 2] ! or: ! [- pi / 2, rlatv(nbp_lat - 1)] ! respectively. ! "o3_regr_lat(:, k, :, :)" is for pressure level "plev(k)". ! Third dimension is month number, 1 for January. ! "o3_regr_lat(:, :, :, 1)" is average day and night, ! "o3_regr_lat(:, :, :, 2)" is for daylight. real, allocatable:: o3_out(:, :, :, :) ! (nbp_lat, n_plev, 360, read_climoz) ! regridded ozone climatology ! "o3_out(j, k, l, :)" is at latitude "rlatu(j)", pressure ! level "plev(k)" and date "January 1st 0h" + "tmidday(l)", in a ! 360-day calendar. ! "o3_out(:, :, :, 1)" is average day and night, ! "o3_out(:, :, :, 2)" is for daylight. integer j, k, l,m ! For NetCDF: integer ncid_in, ncid_out ! IDs for input and output files integer varid_plev, varid_time, varid, ncerr, dimid character(len=80) press_unit ! pressure unit integer varid_in(read_climoz), varid_out(read_climoz) ! index 1 is for average ozone day and night, index 2 is for ! daylight ozone. real, parameter:: tmidmonth(0:13) = (/(-15. + 30. * l, l = 0, 13)/) ! (time to middle of month, in days since January 1st 0h, in a ! 360-day calendar) ! (We add values -15 and 375 so that, for example, day 3 of the year is ! interpolated between the December and the January value.) real, parameter:: tmidday(360) = (/(l + 0.5, l = 0, 359)/) ! (time to middle of day, in days since January 1st 0h, in a ! 360-day calendar) !--------------------------------- print *, "Call sequence information: regr_lat_time_climoz" call assert(read_climoz == 1 .or. read_climoz == 2, "regr_lat_time_climoz") call nf95_open("climoz.nc", nf90_nowrite, ncid_in) ! Get coordinates from the input file: call nf95_inq_varid(ncid_in, "latitude", varid) call nf95_gw_var(ncid_in, varid, latitude) ! Convert from degrees to rad, because we will take the sine of latitude: latitude = latitude / 180. * pi n_lat = size(latitude) ! We need to supply the latitudes to "regr1_conserv" in ! ascending order, so invert order if necessary: desc_lat = latitude(1) > latitude(n_lat) if (desc_lat) latitude = latitude(n_lat:1:-1) ! Compute edges of latitude intervals: allocate(sin_lat_in_edg(n_lat + 1)) sin_lat_in_edg(1) = - 1. forall (j = 2:n_lat) sin_lat_in_edg(j) = sin((latitude(j - 1) & + latitude(j)) / 2.) sin_lat_in_edg(n_lat + 1) = 1. deallocate(latitude) ! pointer call nf95_inq_varid(ncid_in, "plev", varid) call nf95_gw_var(ncid_in, varid, plev) n_plev = size(plev) ! We only need the pressure coordinate to copy it to the output file. ! The program "gcm" will assume that pressure levels are in ! ascending order in the regridded climatology so invert order if ! necessary: desc_plev = plev(1) > plev(n_plev) if (desc_plev) plev = plev(n_plev:1:-1) call nf95_get_att(ncid_in, varid, "units", press_unit) if (press_unit == "Pa") then ! Convert to hPa: plev = plev / 100. elseif (press_unit /= "hPa") then print *, "regr_lat_time_climoz: the only recognized units are Pa " & // "and hPa." stop 1 end if ! Create the output file and get the variable IDs: call prepare_out(ncid_in, n_plev, ncid_out, varid_out, varid_plev, & varid_time) ! Write remaining coordinate variables: call nf95_put_var(ncid_out, varid_plev, plev) call nf95_put_var(ncid_out, varid_time, tmidday) deallocate(plev) ! pointer ! Get the number of months: call nf95_inq_dimid(ncid_in, "time", dimid) call nf95_inquire_dimension(ncid_in, dimid, nclen=n_month) allocate(o3_in(n_lat, n_plev, n_month, read_climoz)) call nf95_inq_varid(ncid_in, "tro3", varid_in(1)) ncerr = nf90_get_var(ncid_in, varid_in(1), o3_in(:, :, :, 1)) call handle_err("regr_lat_time_climoz nf90_get_var tro3", ncerr, ncid_in) if (read_climoz == 2) then call nf95_inq_varid(ncid_in, "tro3_daylight", varid_in(2)) ncerr = nf90_get_var(ncid_in, varid_in(2), o3_in(:, :, :, 2)) call handle_err("regr_lat_time_climoz nf90_get_var tro3_daylight", & ncerr, ncid_in, varid_in(2)) end if if (desc_lat) o3_in = o3_in(n_lat:1:-1, :, :, :) if (desc_plev) o3_in = o3_in(:, n_plev:1:-1, :, :) do m = 1, read_climoz ncerr = nf90_get_att(ncid_in, varid_in(m), "missing_value", & missing_value) if (ncerr == nf90_noerr) then do l = 1, n_month ! Take care of latitudes where values are all missing: ! Next to the south pole: j = 1 do while (o3_in(j, 1, l, m) == missing_value) j = j + 1 end do if (j > 1) o3_in(:j-1, :, l, m) = & spread(o3_in(j, :, l, m), dim=1, ncopies=j-1) ! Next to the north pole: j = n_lat do while (o3_in(j, 1, l, m) == missing_value) j = j - 1 end do if (j < n_lat) o3_in(j+1:, :, l, m) = & spread(o3_in(j, :, l, m), dim=1, ncopies=n_lat-j) ! Take care of missing values at high pressure: do j = 1, n_lat ! Find missing values, starting from top of atmosphere ! and going down. ! We have already taken care of latitudes full of ! missing values so the highest level has a valid value. k = 2 do while (o3_in(j, k, l, m) /= missing_value .and. k < n_plev) k = k + 1 end do ! Replace missing values with the valid value at the ! lowest level above missing values: if (o3_in(j, k, l, m) == missing_value) & o3_in(j, k:n_plev, l, m) = o3_in(j, k-1, l, m) end do end do else print *, "regr_lat_time_climoz: field ", m, & ", no missing value attribute" end if end do call nf95_close(ncid_in) allocate(o3_regr_lat(nbp_lat, n_plev, 0:13, read_climoz)) allocate(o3_out(nbp_lat, n_plev, 360, read_climoz)) ! Regrid in latitude: ! We average with respect to sine of latitude, which is ! equivalent to weighting by cosine of latitude: if (n_month == 12) then print *, & "Found 12 months in ozone climatologies, assuming periodicity..." call regr1_conserv(o3_in, xs = sin_lat_in_edg, & xt = (/- 1., sin(boundslat_reg(nbp_lat - 1:1:- 1, south)), 1./), & vt = o3_regr_lat(nbp_lat:1:- 1, :, 1:12, :), & slope = slopes(o3_in, sin_lat_in_edg)) ! (invert order of indices in "o3_regr_lat" because "rlatu" is ! in descending order) ! Duplicate January and December values, in preparation of time ! interpolation: o3_regr_lat(:, :, 0, :) = o3_regr_lat(:, :, 12, :) o3_regr_lat(:, :, 13, :) = o3_regr_lat(:, :, 1, :) else print *, "Using 14 months in ozone climatologies..." call regr1_conserv(o3_in, xs = sin_lat_in_edg, & xt = (/- 1., sin(boundslat_reg(nbp_lat - 1:1:- 1, south)), 1./), & vt = o3_regr_lat(nbp_lat:1:- 1, :, :, :), & slope = slopes(o3_in, sin_lat_in_edg)) ! (invert order of indices in "o3_regr_lat" because "rlatu" is ! in descending order) end if ! Regrid in time by linear interpolation: o3_out = regr3_lint(o3_regr_lat, tmidmonth, tmidday) ! Write to file: do m = 1, read_climoz call nf95_put_var(ncid_out, varid_out(m), o3_out(nbp_lat:1:-1, :, :, m)) ! (The order of "rlatu" is inverted in the output file) end do call nf95_close(ncid_out) end subroutine regr_lat_time_climoz !******************************************** subroutine prepare_out(ncid_in, n_plev, ncid_out, varid_out, varid_plev, & varid_time) ! This subroutine creates the NetCDF output file, defines ! dimensions and variables, and writes one of the coordinate variables. use mod_grid_phy_lmdz, ONLY : nbp_lat use netcdf95, only: nf95_create, nf95_def_dim, nf95_def_var, & nf95_put_att, nf95_enddef, nf95_copy_att, nf95_put_var use netcdf, only: nf90_clobber, nf90_float, nf90_global use nrtype, only: pi use regular_lonlat_mod, only : lat_reg integer, intent(in):: ncid_in, n_plev integer, intent(out):: ncid_out, varid_plev, varid_time integer, intent(out):: varid_out(:) ! dim(1 or 2) ! "varid_out(1)" is for average ozone day and night, ! "varid_out(2)" is for daylight ozone. ! Variables local to the procedure: integer ncerr integer dimid_rlatu, dimid_plev, dimid_time integer varid_rlatu !--------------------------- print *, "Call sequence information: prepare_out" call nf95_create("climoz_LMDZ.nc", nf90_clobber, ncid_out) ! Dimensions: call nf95_def_dim(ncid_out, "time", 360, dimid_time) call nf95_def_dim(ncid_out, "plev", n_plev, dimid_plev) call nf95_def_dim(ncid_out, "rlatu", nbp_lat, dimid_rlatu) ! Define coordinate variables: call nf95_def_var(ncid_out, "time", nf90_float, dimid_time, varid_time) call nf95_put_att(ncid_out, varid_time, "units", "days since 2000-1-1") call nf95_put_att(ncid_out, varid_time, "calendar", "360_day") call nf95_put_att(ncid_out, varid_time, "standard_name", "time") call nf95_def_var(ncid_out, "plev", nf90_float, dimid_plev, varid_plev) call nf95_put_att(ncid_out, varid_plev, "units", "millibar") call nf95_put_att(ncid_out, varid_plev, "standard_name", "air_pressure") call nf95_put_att(ncid_out, varid_plev, "long_name", "air pressure") call nf95_def_var(ncid_out, "rlatu", nf90_float, dimid_rlatu, varid_rlatu) call nf95_put_att(ncid_out, varid_rlatu, "units", "degrees_north") call nf95_put_att(ncid_out, varid_rlatu, "standard_name", "latitude") ! Define the primary variables: call nf95_def_var(ncid_out, "tro3", nf90_float, & (/dimid_rlatu, dimid_plev, dimid_time/), varid_out(1)) call nf95_put_att(ncid_out, varid_out(1), "long_name", & "ozone mole fraction") call nf95_put_att(ncid_out, varid_out(1), "standard_name", & "mole_fraction_of_ozone_in_air") if (size(varid_out) == 2) then call nf95_def_var(ncid_out, "tro3_daylight", nf90_float, & (/dimid_rlatu, dimid_plev, dimid_time/), varid_out(2)) call nf95_put_att(ncid_out, varid_out(2), "long_name", & "ozone mole fraction in daylight") end if ! Global attributes: ! The following commands, copying attributes, may fail. ! That is OK. ! It should just mean that the attribute is not defined in the input file. call nf95_copy_att(ncid_in, nf90_global, "Conventions", ncid_out, & nf90_global, ncerr) call handle_err_copy_att("Conventions") call nf95_copy_att(ncid_in, nf90_global, "title", ncid_out, nf90_global, & ncerr) call handle_err_copy_att("title") call nf95_copy_att(ncid_in, nf90_global, "institution", ncid_out, & nf90_global, ncerr) call handle_err_copy_att("institution") call nf95_copy_att(ncid_in, nf90_global, "source", ncid_out, nf90_global, & ncerr) call handle_err_copy_att("source") call nf95_put_att(ncid_out, nf90_global, "comment", "Regridded for LMDZ") call nf95_enddef(ncid_out) ! Write one of the coordinate variables: call nf95_put_var(ncid_out, varid_rlatu, lat_reg(nbp_lat:1:-1) / pi * 180.) ! (convert from rad to degrees and sort in ascending order) contains subroutine handle_err_copy_att(att_name) use netcdf, only: nf90_noerr, nf90_strerror character(len=*), intent(in):: att_name !---------------------------------------- if (ncerr /= nf90_noerr) then print *, "regr_lat_time_climoz_m prepare_out nf95_copy_att " & // att_name // " -- " // trim(nf90_strerror(ncerr)) end if end subroutine handle_err_copy_att end subroutine prepare_out end module regr_lat_time_climoz_m