= User-defined output quantities = [[TracNav(doc/userint/toc)]] A very typical request of users is the calculation and output of quantities which are not part of PALM's standard output. The basic user interface includes a number of subroutines which allow the calculation of user-defined quantities and output of these quantities as:\\ 1. [#a1.Outputofuser-definedverticalprofiles (horizontally averaged) vertical profiles] 2. [#a2.Outputofuser-definedtimeseries time series] 3. [#a3.Outputofuser-defined2dcrosssections3dvolumedataormaskeddata 2d cross section, 3d volume data or masked data] 4. [#a5.Outputofuser-definedspectra spectra] 5. [#a6.Outputofuser-definedflightmeasurements virtual flights]\\ In the following, the generation of such output quantities is explained step by step. Furthermore, the respective subroutines already contain sample code lines (written as comment lines) for defining, calculating and output of such quantities. Output times, averaging intervals, etc. are steered by the same variables as used for the standard PALM output quantities, e.g. [../../d3par#dt_data_output dt_data_output].\\\\ == 1. Output of user-defined vertical profiles This example shows the output of the quantity "turbulent resolved-scale horizontal momentum flux" (''u*v*''). If more than one user-defined quantity shall be output, the following steps have to be carried out in the same way for each of the quantities.\\ 1. The quantity has to be given a unique string identifier, e.g.'' 'u*v*'.'' This identifier must be different from the identifiers used for the PALM standard output (see list in description of parameter [../../d3par#data_output_pr data_output_pr]). The identifier must not contain more than '''20''' characters. In case that 2d cross section output is defined on one single level only (see chapter 3, paragraph 9, further below), the identifier string must contain an asterisk ({{{"*"}}}). To switch on output of the quantity, the user has to assign the string identifier to the parameter [../../userpar#data_output_pr_user data_output_pr_user], eg.:\\ {{{ data_output_pr_user = 'u*v*' }}}, \\ 2. For the quantity, an identification number, a physical unit, and the vertical grid on which it is defined (u- or w-grid), has to be assigned (subroutine [../int#user_check_data_output_pr user_check_data_output_pr]): \\\\ {{{CASE ( 'u*v*' )}}} \\ {{{user_pr_index = pr_palm +}}} [[span({{{1}}} ,style=color: red)]] {{{! identification number}}} \\ {{{dopr_index(var_count) = user_pr_index}}} \\ {{{dopr_unit =}}} [[span({{{'m2s2'}}},style=color: red)]] {{{! physical unit}}} \\ {{{unit = dopr_unit}}} \\ {{{hom(:,2,user_pr_index,:) = SPREAD(}}} [[span({{{zu}}},style=color: red)]]{{{, 2, statistic_regions+1 ) ! vertical grid }}} The identification number (user_pr_index) must be within the range [ {{{pr_palm+1 , pr_palm+max_pr_user}}} ], where {{{max_pr_user}}} is the number of user-defined profiles as given by parameter [../../userpar#data_output_pr_user data_output_pr_user] in the respective PALM run. The physical unit has to be given with respect to the netCDF conventions. If no unit is given, PALM will abort. The vertical grid has to be either {{{zu}}} ({{{u}}}-grid) or {{{zw}}} ({{{w}}}-grid). 3. The quantity has to be calculated for all grid points (subroutine user_statistics): \\\\ {{{!$OMP DO}}} \\ {{{DO i = nxl, nxr}}} \\ {{{DO j = nys, nyn}}} \\ {{{DO k = nzb+1, nzt}}} \\ {{{sums_l(k,pr_palm+1,tn) = sums_l(k,pr_palm+1,tn) + & }}} \\ [[span({{{ ( 0.5*(u(k,j,i)+u(k,j,i+1))-hom(k,1,1,sr))*&}}},style=color: red)]] \\ [[span({{{ ( 0.5*(v(k,j,i)+v(k,j+1,i))-hom(k,1,2,sr)) &}}},style=color: red)]] \\ {{{* rmask(j,i,sr)}}} {{{ENDDO}}} \\ {{{ENDDO}}} \\ {{{ENDDO}}} \\ The turbulent resolved-scale momentum flux ''u*v*'' is defined as the product of the deviations of the horizontal velocities from their respective horizontally averaged mean values. These mean values are stored in array {{{hom(..,1,1,sr)}}} and {{{hom(..,1,2,sr)}}} for the u- and v-component, respectively. Since due to the staggered grid, u and v are not defined at the same grid points, they have to be interpolated appropriately (here to the center of the grid box). The result of the calculation is stored in array {{{sums_l}}}. The second index of this array is the identification number of the profile which must match the one given in the previous step 2. '''Attention:''' All quantities that are calculated here, need to be switched on via parameter {{{data_output_pr_user}}}, otherwise the run may crash, because the array {{{sums_l}}} is not allocated with its correct size. \\\\ == 2. Output of user-defined time series This example shows the output of two time series for the maxima of the absolute values of the horizontal velocities u and v. If more than one user-defined quantity shall be output, the following steps have to be carried out in the same way for each of the quantities.\\\\ 1. For each time series quantity you have to give a label and a unit in subroutine [../int#user_init user_init] (user_check_data_output_ts for newer versions), which will be used for the netCDF file. They must not contain more than '''13''' characters. The value of {{{dots_num}}} and {{{dots_num_user}}} have to be increased by the number of new time series quantities. The old value of {{{dots_num}}} has to be stored in {{{dots_num_palm}}}. {{{dots_num_palm = dots_num}}} \\ {{{dots_num = dots_num + 1}}} \\ {{{dots_num_user = dots_num_user + 1}}} \\ {{{dots_label(dots_num) = 'abs_umax'}}}' \\ {{{dots_unit(dots_num) = 'm/s'}}} \\ {{{dots_num = dots_num + 1}}} \\ {{{dots_num_user = dots_num_user + 1}}} \\ {{{dots_label(dots_num) = 'abs_vmax'}}} \\ {{{dots_unit(dots_num) = 'm/s'}}} \\ 2. These quantities are calculated and output in subroutine [../int#user_statistics user_statistics] for every statistic region {{{sr}}} defined by the user, but at least for the region "total domain": {{{ ts_value_l(1) = ABS( u_max ) }}} \\ {{{ ts_value_l(2) = ABS( v_max ) }}} \\ Subsequently, collect / send values to PE0, because only PE0 outputs the time series. However, collection is done by taking the sum over all processors. You may have to normalize this sum, depending on the quantity that you like to calculate. For serial runs, nothing has to be done: {{{#if defined( __parallel )}}}\\ {{{IF ( collective_wait ) CALL MPI_BARRIER( comm2d, ierr )}}} \\ {{{CALL MPI_ALLREDUCE( ts_value_l(1),ts_value(dots_num_palm+1,sr),dots_num_user, MPI_REAL, MPI_MAX, comm2d, ierr )}}} \\ {{{#else}}}\\ {{{ts_value(dots_num_palm+1:dots_num_palm+dots_num_user,sr) = ts_value_l}}}\\ {{{#endif}}} \\ '''HINT:''' If the time series value that you are calculating has the same value on all PEs, you can omit the MPI_ALLREDUCE call and assign {{{ts_value(dots_num_palm+1:dots_num_palm+dots_num_user,sr) = ts_value_l}}} directly.\\ == 3. Output of user-defined 2d cross sections, 3d volume data or masked data This example shows the output of the quantity "square of the u-component" ('''Note:''' this quantity could of course easily be calculated from the u-component by postprocessing the PALM output so that calculation within PALM is not necessarily required). If more than one user-defined quantity shall be output, the following steps have to be carried out in the same way for each of the quantities. 1. For output of '''2d cross sections''' and '''3d volume data''', the quantity has to be given a unique string identifier, e.g.'' 'u2'.'' This identifier must be different from the identifiers used for the PALM standard output (see list in description of parameter [../../d3par#data_output data_output]). The identifier must not contain more than '''20''' characters. To switch on output of this quantity, the user has to assign the string identifier to the parameter [../../userpar#data_output_user data_output_user], eg.: \\ {{{ data_output_user = 'u2', 'u2_xy_av' }}} The pure string'' 'u2' ''switches on the output of instantaneous 3d volume data. Output of cross section data and time averaged data is switched on by additionally appending the strings'' '_xy', '_xz', '_yz', ''and/or'' '_av' ''(for a detailed explanation see parameter [../../d3par#data_output data_output]).\\ 2. For output of '''masked data''', the quantity has to be given a unique string identifier, e.g.'' 'u2'.'' This identifier must be different from the identifiers used for the PALM standard output (see list in description of parameter [../../d3par#data_output_masks data_output_masks]). To switch on output of this quantity, the user has to assign the string identifier to the parameter [../../userpar#data_output_masks_user data_output_masks_user], eg.: \\ {{{ data_output_masks_user(1,:) = 'u2', }}} 3. In order to store the quantities' data within PALM, a 3d data array has to be declared in module [../int#user user] (user_module.f90): \\ {{{ REAL(wp), DIMENSION(:,:,:), ALLOCATABLE :: u2, u2_av }}} // The second array {{{u2_av}}} is needed in case that output of time averaged data is requested. It is used to store the sum of the data of the respective time levels over which the average has to be carried out. \\ 4. [=#Allocate]The data array has to be allocated in subroutine [../int#user_init user_init]: \\ {{{ALLOCATE( u2(nzb:nzt+1,nysg:nyng,nxlg:nxrg) ) }}} 5. The quantity has to be given a unit (subroutine [../int#user_check_data_output user_check_data_output]): \\ {{{ CASE ( 'u2' )}}} \\ {{{ unit = 'm2/s2' }}} \\ Otherwise, PALM will abort. \\ 6. The vertical grid on which the quantity is defined (given by the levels '{{{zu}}}' or '{{{zw}}}', on which the u- or w-component of the velocity are defined) has to be specified for the netCDF output files in subroutine [../int#user_define_netcdf_grid user_define_netcdf_grid]: {{{ CASE ( 'u2', 'u2_xy', 'u2_xz', 'u2_yz' ) }}} \\ {{{ grid = 'zu' }}} \\ As the example shows, this grid has to be defined for the 3d volume data as well as for all of the three cross sections. \\ 7. After each time step, the quantity has to be calculated at all grid points and to be stored. This has to be done in subroutine [../int#user_actions user_actions] at location 'after_integration': \\ {{{ CASE ( 'after_integration' ) }}} \\ {{{!}}} \\ {{{!-- Enter actions to be done after every time integration (before}}} \\ {{{!-- data output) }}} \\ {{{!-- Sample for user-defined output: }}} \\ {{{ DO i = nxlg, nxrg }}} \\ {{{ DO j = nysg, nyng }}} \\ {{{ DO k = nzb, nzt+1 }}} \\ {{{ u2(k,j,i) = u(k,j,i)**2 }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ 8. In case that output of time-averaged data is requested, the sum- and average-operations as well as the allocation of the sum-array have to be carried out in subroutine [../int#user_3d_data_averaging user_3d_data_averaging]: \\ {{{ IF ( mode == 'allocate' ) THEN }}} \\ {{{ ... }}} \\ {{{ CASE ( 'u2' ) }}} \\ {{{ IF ( .NOT. ALLOCATED( u2_av ) ) THEN }}} \\ {{{ ALLOCATE( u2_av(nzb:nzt+1,nysg:nyng,nxlg:nxrg) ) }}} \\ {{{ ENDIF }}} \\ {{{ u2_av = 0.0 }}} \\ {{{ ... }}} \\ {{{ ELSEIF ( mode == 'sum' ) THEN }}} \\ {{{ ... }}} \\ {{{ CASE ( 'u2' ) }}} \\ {{{ IF ( ALLOCATED( u2_av ) ) THEN }}} \\ {{{ DO i = nxlg, nxrg }}} \\ {{{ DO j = nysg, nyng }}} \\ {{{ DO k = nzb, nzt+1 }}} \\ {{{ u2_av(k,j,i) = u2_av(k,j,i) + u2(k,j,i) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDIF}}} \\ {{{ ... }}} \\ {{{ ELSEIF ( mode == 'average' ) THEN }}} \\ {{{ ... }}} \\ {{{ CASE ( 'u2' ) }}} \\ {{{ IF ( ALLOCATED( u2_av ) ) THEN }}} \\ {{{ DO i = nxlg, nxrg }}} \\ {{{ DO j = nysg, nyng }}} \\ {{{ DO k = nzb, nzt+1 }}} \\ {{{ u2_av(k,j,i) = u2_av(k,j,i) / REAL( average_count_3d, KIND=wp ) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDIF}}} \\ {{{ ... }}} \\ 9. For output of '''2d cross sections''', the data of the quantity has to be resorted to array {{{local_pf}}} in subroutine [../int#user_data_output_2d user_data_output_2d]. Also the vertical grid, on which the quantity is defined, has to be set again: \\ {{{ CASE ( 'u2_xy', 'u2_xz', 'u2_yz' ) }}} \\ {{{ IF ( av == 0 ) THEN }}} \\ {{{ DO i = nxl, nxr }}} \\ {{{ DO j = nys, nyn }}} \\ {{{ DO k = nzb_do, nzt_do }}} \\ {{{ local_pf(i,j,k) = u2(k,j,i) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ELSE }}} \\ {{{ IF ( .NOT. ALLOCATED( u2_av ) ) THEN }}} \\ {{{ ALLOCATE( u2_av(nzb:nzt+1,nysg:nyng,nxlg:nxrg) ) }}} \\ {{{ u2_av = REAL( fill_value, KIND = wp ) }}} \\ {{{ ENDIF }}} \\ {{{ DO i = nxl, nxr }}} \\ {{{ DO j = nys, nyn }}} \\ {{{ DO k = nzb_do, nzt_do }}} \\ {{{ local_pf(i,j,k) = u2_av(k,j,i) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDIF }}} \\ {{{ grid = 'zu' }}} \\ The {{{ELSE}}} case is only needed in case that output of time-averaged data is requested. \\ As a special case, ''xy'' cross section output can also be defined at one single level at height {{{k=nzb+1}}} on the u-grid. This features is useful for output of surface data (e.g. heat fluxes). In this case, the corresponding 2d data has to be resorted to the array {{{local_pf(i,j,nzb+1)}}}. In addition to this, the grid in [../int#user_define_netcdf_grid user_define_netcdf_grid] as well as in [../#user_data_output_2d user_data_output_2d] must be set to {{{grid = 'zu1'}}}. Furthermore, the identifier string must contain an asterisk ({{{'*'}}}). {{{ CASE ( 'u2*_xy' ) }}} \\ {{{ IF ( av == 0 ) THEN }}} \\ {{{ DO i = nxlg, nxrg }}} \\ {{{ DO j = nysg, nyng }}} \\ {{{ local_pf(i,j,nzb+1) = u2(j,i) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ELSE }}} \\ {{{ DO i = nxlg, nxrg }}} \\ {{{ DO j = nysg, nyng }}} \\ {{{ local_pf(i,j,nzb+1) = u2_av(j,i) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDIF }}} \\ {{{ grid = 'zu1' }}} \\ {{{ two_d = .TRUE. }}} \\ Note that {{{two_d = .TRUE.}}} is necessary for output of a 2d data slice. \\ 10. For output of '''3d volume data''', the data of the quantity has to be resorted to {{{array local_pf}}} in subroutine [../int#user_data_output_3d user_data_output_3d].: {{{ CASE ( 'u2' ) }}} \\ {{{ IF ( av == 0 ) THEN }}} \\ {{{ DO i = nxlg, nxrg }}} \\ {{{ DO j = nysg, nyng }}} \\ {{{ DO k = nzb, nz_do }}} \\ {{{ local_pf(i,j,k) = u2(k,j,i) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ELSE }}} \\ {{{ DO i = nxlg, nxrg }}} \\ {{{ DO j = nysg, nyng }}} \\ {{{ DO k = nzb, nz_do }}} \\ {{{ local_pf(i,j,k) = u2_av(k,j,i) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDIF }}} \\ The {{{ELSE}}} case is only needed in case that output of time-averaged data is requested. 11. For output of '''masked data''', the data of the quantity has to be resorted to {{{array local_pf}}} in subroutine [../int#user_data_output_mask user_data_output_mask].: {{{ CASE ( 'u2' ) }}} \\ {{{ IF ( av == 0 ) THEN }}} \\ {{{ DO i = 1, mask_size_l(mid,1) }}} \\ {{{ DO j = 1, mask_size_l(mid,2) }}} \\ {{{ DO k = 1, mask_size_l(mid,3) }}} \\ {{{ local_pf(i,j,k) = u2(mask_k(mid,k), & }}} \\ {{{ mask_j(mid,j),mask_i(mid,i)) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ELSE }}} \\ {{{ DO i = 1, mask_size_l(mid,1) }}} \\ {{{ DO j = 1, mask_size_l(mid,2) }}} \\ {{{ DO k = 1, mask_size_l(mid,3) }}} \\ {{{ local_pf(i,j,k) = u2_av(mask_k(mid,k), & }}} \\ {{{ mask_j(mid,j),mask_i(mid,i)) }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDDO }}} \\ {{{ ENDIF }}} \\ The {{{ELSE}}} case is only needed in case that output of time-averaged data is requested. 12. In case of job chains, the sum array has to be written to the (binary) restart file (local filename [../../iofiles#BINOUT BINOUT]) in subroutine [../int#user_last_actions user_last_actions]: {{{ IF ( ALLOCATED( u2_av ) ) THEN }}}\\ {{{ WRITE ( 14 ) 'u2_av' }}}\\ {{{ WRITE ( 14 ) u2_av }}}\\ {{{ ENDIF }}}\\ Otherwise, the calculated time-average may be wrong. In the restart run, this quantity has to be read from the restart file by including the following code in subroutine [../int#user_read_restart_data user_read_restart_data]: {{{ IF ( initializing_actions == 'read_restart_data' ) THEN }}}\\ {{{ READ ( 13 ) field_char }}}\\ {{{ DO WHILE ( TRIM( field_char ) /= '*** end user ***' ) }}}\\ {{{ DO k = 1, overlap_count }}}\\ {{{ nxlf = nxlfa(i,k) }}}\\ {{{ nxlc = nxlfa(i,k) + offset_xa(i,k)}}}\\ {{{ nxrf = nxrfa(i,k)}}}\\ {{{ nxrc = nxrfa(i,k) + offset_xa(i,k)}}}\\ {{{ nysf = nysfa(i,k)}}}\\ {{{ nysc = nysfa(i,k) + offset_ya(i,k)}}}\\ {{{ nynf = nynfa(i,k)}}}\\ {{{ nync = nynfa(i,k) + offset_ya(i,k)}}}\\\\ {{{ SELECT CASE ( TRIM( field_char ) ) }}}\\ {{{ CASE ( 'u2_av' ) }}}\\ {{{ IF ( .NOT. ALLOCATED( u2_av ) ) THEN }}}\\ {{{ ALLOCATE( u2_av(nzb:nzt+1,nysg:nyng,nxlg:nxrg) ) }}}\\ {{{ ENDIF }}}\\ {{{ IF ( k == 1 ) READ ( 13 ) tmp_3d }}}\\ {{{ u2_av(:,nysc-nbgp:nync+nbgp,nxlc-nbgp:nxrc+nbgp) = & }}}\\ {{{ tmp_3d(:,nysf-nbgp:nynf+nbgp,nxlf-nbgp:nxrf+nbgp) }}}\\ {{{ CASE DEFAULT }}}\\ {{{ WRITE( message_string, * ) 'unknown variable named "', &}}}\\ {{{ TRIM( field_char ), '" found in', &}}}\\ {{{ '&data from prior run on PE ', myid}}}\\ {{{ CALL message('user_read_restart_data', 'UI0012', 1, 2, 0, 6, 0) }}}\\ {{{ END SELECT }}}\\ {{{ ENDDO }}}\\ {{{ READ ( 13 ) field_char }}}\\ {{{ ENDDO }}}\\ {{{ ENDIF }}} == 4. Output of user-defined spectra This example shows the output of the quantity "turbulent resolved-scale horizontal momentum flux" ''(u*v*).'' If more than one user-defined quantity shall be output, the following steps have to be carried out in the same way for each of the quantities. 1. The calculation of user-defined spectra is closely linked with the calculation of [#part_1 part 1. (user-defined vertical profiles)] and [#part_3 part 3. (user-defined 3d volume data)]. Therefore, the following prerequisites apply for each user-defined spectra quantity:\\\\ A. From [#part_1 part 1. (user-defined vertical profiles)] steps 2 and 3. See the sample code (as comment lines) for'' 'u*v*' ''and ustvst, respectively. (Actual output of vertical profiles - step 1 - is not required.) B. From [#part_3 part 3. (user-defined 3d volume data)] steps 2, 3, 4, 5, and 6. See the sample code (as comment lines) for'' 'u*v*' ''and {{{ustvst}}}, respectively. (Actual output of 3d volume data - step 1 - is not required.) C. The quantity has to be given a unique string identifier, e.g.'' 'u*v*'.'' This identifier must be different from the identifiers used for the PALM standard output (see list in description of package parameter [../../sppar#data_output_sp data_output_sp]). To switch on output of this quantity, the user has to assign the string identifier to the package parameter [../../sppar#data_output_sp data_output_sp], eg.: {{{ data_output_sp = 'u*v*' }}} Item A. and item B. as prerequisites for C. require a naming convention of identical identifiers, e.g. [../../userpar#data_output_pr_user data_output_pr_user]='' 'u*v*','' [../../userpar#data_output_user data_output_user] ='' 'u*v*' ''and [../../sppar#data_output_sp data_output_sp]='' 'u*v*'.'' This naming convention applies only in case of user-defined spectra. 2. Edit the subroutine as follows: {{{ IF ( mode == 'preprocess' ) THEN }}} \\ {{{ SELECT CASE ( TRIM( data_output_sp(m) ) ) }}} \\ {{{ CASE ( 'u', 'v', 'w', 'pt', 'q' ) }}} \\ {{{ !-- Not allowed here since these are the standard quantities used in }}} \\ {{{ !-- preprocess_spectra. }}} \\ [[span({{{CASE ( 'u*v*' )}}},style=color: red)]] \\ [[span({{{pr = pr_palm+1}}},style=color: red)]] \\ [[span({{{d(nzb+1:nzt,nys:nyn,nxl:nxr) = ustvst(nzb+1:nzt,nys:nyn,nxl:nxr)}}},style=color: red)]] \\ {{{ CASE DEFAULT }}} \\ {{{ message_string = 'Spectra of ' // &}}}\\ {{{ TRIM( data_output_sp(m) ) // ' can not be calculated'}}}\\ {{{ CALL message( 'user_spectra', 'UI0010', 0, 0, 0, 6, 0 )}}}\\ {{{ END SELECT }}} \\ {{{ ELSEIF ( mode == 'data_output' ) THEN }}} \\ {{{ SELECT CASE ( TRIM( data_output_sp(m) ) ) }}} \\ {{{ CASE ( 'u', 'v', 'w', 'pt', 'q' ) }}} \\ {{{ !-- Not allowed here since these are the standard quantities used in }}} \\ {{{ !-- data_output_spectra. }}} \\ [[span({{{CASE ( 'u*v*' )}}},style=color: red)]] \\ [[span({{{pr = 6}}},style=color: red)]] \\ {{{ CASE DEFAULT }}} \\ {{{ message_string = 'Spectra of ' // &}}}\\ {{{ TRIM( data_output_sp(m) ) // ' are not defined'}}}\\ {{{ CALL message( 'user_spectra', 'UI0011', 0, 0, 0, 6, 0 )}}}\\ {{{ END SELECT }}} \\ {{{ ENDIF }}} \\ Note that spectra output requires an additional namelist [wiki:doc/app/sppar &spectra_parameters]. == 5. Output of user-defined flight measurements This example shows the output of two user-defined quantities for the absolute values of the horizontal velocities u and v captured by virtual flight measurements. The given quantities will be captured for each leg. \\\\ 1. At first, the number of user-defined quantities has to be given in [../int#user_init_flight user_init_flight] by {{{num_var_fl_user = num_var_fl_user + 2}}} 2. In the following, for each user-defined quantity you have to give a label and a unit (subroutine [../int#user_init_flight user_init_flight]), which will be used for the netCDF file. They must not contain more than '''13''' characters. {{{CASE ( 1 )}}} {{{dofl_label(k) = TRIM(label_leg) // '_' // 'abs_u'}}}\\ {{{dofl_unit(k) = 'm/s'}}}\\ {{{k = k + 1}}} \\\\ {{{CASE ( 2 )}}} {{{dofl_label(k) = TRIM(label_leg) // '_' // 'abs_v'}}}\\ {{{dofl_unit(k) = 'm/s'}}}\\ {{{k = k + 1}}}\\ 3. The user-defined quantities are calculated in subroutine [../int#user_flight user_flight] at every timestep. Note, the identifier in the {{{CASE()}}} argument must be set accordingly to the settings used in [../int#user_init_flight user_init_flight]. {{{CASE ( 1 )}}} {{{DO i = nxl-1, nxr+1}}} {{{DO j = nys-1, nyn+1}}} {{{DO k = nzb, nzt}}} {{{var(k,j,i) = ABS( u(k,j,i )}}} {{{ENDDO}}} {{{ENDDO}}} {{{ENDDO}}} {{{CASE ( 2 )}}} {{{DO i = nxl-1, nxr+1}}} {{{DO j = nys-1, nyn+1}}} {{{DO k = nzb, nzt}}} {{{var(k,j,i) = ABS( v(k,j,i )}}} {{{ENDDO}}} {{{ENDDO}}} {{{ENDDO}}} \\\\ Flight measurements as well as data output of the respective user-defined quantities is done automatically.