Changes between Version 19 and Version 20 of OMI_observation_modules


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Timestamp:
Nov 28, 2020, 9:57:39 AM (3 months ago)
Author:
lnerger
Comment:

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  • OMI_observation_modules

    v19 v20  
    8989`thisobs%doassim`.
    9090
    91 The main steps performed in this routine are
    92  1. `thisobs%doassim`: Specify whether this observation type is assimilated
    93  1. `thisobs%disttype`: Specify the type of distance computation
    94  1. `thisobs%ncoord`: Specify the number of dimensions used to compute distances
    95  1. `dim_obs_p`: Count the number of available observations
    96  1. `obs_p`: Fill the vector of observations
    97  1. `ocoord_p`: store the coordinates of the observations
    98  1. `ivar_obs_p`: store the inverse error variance of each observation
    99  1. `thisobs%id_obs_p`: store the indices of state vector elements that correspond to an observation (A single value for observation at grid points, or multiple values for derived quantities or interpolation)
    100 
    101 When the observation operator performs interpolation, one further needs to initialize an array of interpolation coefficients (`thisobs%icoeff_p`). For Cartesian distance computation with periodicity one also needs to set `thisobs%domainsize`.
     91The main variables that the filled in this routine are
     92 1. [wiki:OMI_observation_modules#thisobsdoassim thisobs%doassim]: Specify whether this observation type is assimilated
     93 1. [wiki:OMI_observation_modules#thisobsdisttype thisobs%disttype]: Specify the type of distance computation
     94 1. [wiki:OMI_observation_modules#thisobsncoord thisobs%ncoord]: Specify the number of dimensions used to compute distances
     95 1. [wiki:OMI_observation_modules#dim_obs_p dim_obs_p]: Count the number of available observations
     96 1. [wiki:OMI_observation_modules#obs_p obs_p]: Fill the vector of observations
     97 1. [wiki:OMI_observation_modules#ocoord_p ocoord_p]: store the coordinates of the observations
     98 1. [wiki:OMI_observation_modules#ivar_obs_p ivar_obs_p]: store the inverse error variance of each observation
     99 1. [wiki:OMI_observation_modules#thisobsid_obs_p thisobs%id_obs_p]: store the indices of state vector elements that correspond to an observation (A single value for observation at grid points, or multiple values for derived quantities or interpolation)
     100
     101When the observation operator performs interpolation, one further needs to initialize an array of interpolation coefficients ([wiki:OMI_observation_modules#thisobsicoeff_p thisobs%icoeff_p]). For Cartesian distance computation with periodicity one also needs to set [wiki:OMI_observation_modules#thisobsdomainsize thisobs%domainsize].
    102102
    103103When parallel model with domain decomposition is used, the variables with suffix `_p` need to describe the observation information for a particular process domain. The following routine will perform the necessary operations to ensure that the parallelization is taken into account by PDAF.
     
    207207See `/models/lorenz96_omi/` for an example using case 1 with periodicity in one dimension.
    208208
    209 === `thisobs%domainsize` ===
    210 
    211 This array has to be allocated as
    212 {{{
    213    ALLOCATE(thisobs%domainsize(thisobs%ncoord))
    214 }}}
    215 Here one has to specify the size of the domain in each of its thisobs%ncoord dimensions. The information is used to compute the Cartesian distance with periodicity.
    216 
    217 Setting one dimension to 0 or a negative value indicates that there is no periodicity in this direction.
     209
     210=== `dim_obs_p` ===
     211
     212This is a single integer value giving the number of observations. With a parallel model using domain-decomposition this will be the number of observations  for the process sub-domain. For observation files holding all observations one can read these and then check which observation redice within the process sub-domain. `dim_obs_p` will be used to allocate further arrays and as input argument to `PDAFomi_gather_obs`.
     213
     214=== `obs_p` ===
     215
     216This should be a vector of real values. It will be used as an argument to `PDAFomi_gather_obs`. The order of the entries has to be consistent in the arrays `thisobs%id_obs_p`, `obs_p`, `ivar_obs_p`, and `ocoord_p`.
     217
     218
     219=== `ocoord_p` ===
     220
     221This should be a rank-2 array of real values with size (thisobs%ncoord, dim_obs_p). It will be used as an argument to `PDAFomi_gather_obs`. The order of the entries has to be consistent in the arrays `thisobs%id_obs_p`, `obs_p`, `ivar_obs_p`, and `ocoord_p`.
     222
     223The coordinates of the observation with index `k` are given by `ocoord_p(:,k)`.
     224
     225
     226=== `ivar_obs_p` ===
     227
     228This should be a vector of real values. It will be used as an argument to `PDAFomi_gather_obs`. The order of the entries has to be consistent in the arrays `thisobs%id_obs_p`, `obs_p`, `ivar_obs_p`, and `ocoord_p`.
    218229
    219230
     
    234245
    235246
     247=== `thisobs%domainsize` ===
     248
     249This array has to be allocated as
     250{{{
     251   ALLOCATE(thisobs%domainsize(thisobs%ncoord))
     252}}}
     253Here one has to specify the size of the domain in each of its thisobs%ncoord dimensions. The information is used to compute the Cartesian distance with periodicity.
     254
     255Setting one dimension to 0 or a negative value indicates that there is no periodicity in this direction.
     256
     257
    236258=== `thisobs%icoeff_p` ===
    237259