Changeset 11577 for NEMO/trunk/doc/latex/NEMO/subfiles/chap_OBS.tex
- Timestamp:
- 2019-09-19T19:01:38+02:00 (5 years ago)
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NEMO/trunk/doc/latex/NEMO/subfiles/chap_OBS.tex
r11567 r11577 32 32 The OBS code is called from \mdl{nemogcm} for model initialisation and to calculate the model equivalent values for observations on the 0th time step. 33 33 The code is then called again after each time step from \mdl{step}. 34 The code is only activated if the \nam{obs} namelist logical \np{ln \_diaobs} is set to true.34 The code is only activated if the \nam{obs} namelist logical \np{ln_diaobs}{ln\_diaobs} is set to true. 35 35 36 36 For all data types a 2D horizontal interpolator or averager is needed to … … 42 42 Some profile observation types (\eg\ tropical moored buoys) are made available as daily averaged quantities. 43 43 The observation operator code can be set-up to calculate the equivalent daily average model temperature fields using 44 the \np{nn \_profdavtypes} namelist array.44 the \np{nn_profdavtypes}{nn\_profdavtypes} namelist array. 45 45 Some SST observations are equivalent to a night-time average value and 46 46 the observation operator code can calculate equivalent night-time average model SST fields by 47 setting the namelist value \np{ln \_sstnight} to true.47 setting the namelist value \np{ln_sstnight}{ln\_sstnight} to true. 48 48 Otherwise (by default) the model value from the nearest time step to the observation time is used. 49 49 … … 93 93 94 94 Options are defined through the \nam{obs} namelist variables. 95 The options \np{ln \_t3d} and \np{ln\_s3d} switch on the temperature and salinity profile observation operator code.96 The filename or array of filenames are specified using the \np{cn \_profbfiles} variable.95 The options \np{ln_t3d}{ln\_t3d} and \np{ln_s3d}{ln\_s3d} switch on the temperature and salinity profile observation operator code. 96 The filename or array of filenames are specified using the \np{cn_profbfiles}{cn\_profbfiles} variable. 97 97 The model grid points for a particular observation latitude and longitude are found using 98 98 the grid searching part of the code. 99 99 This can be expensive, particularly for large numbers of observations, 100 setting \np{ln \_grid\_search\_lookup} allows the use of a lookup table which101 is saved into an \np{cn \_gridsearch} file (or files).100 setting \np{ln_grid_search_lookup}{ln\_grid\_search\_lookup} allows the use of a lookup table which 101 is saved into an \np{cn_gridsearch}{cn\_gridsearch} file (or files). 102 102 This will need to be generated the first time if it does not exist in the run directory. 103 103 However, once produced it will significantly speed up future grid searches. 104 Setting \np{ln \_grid\_global} means that the code distributes the observations evenly between processors.104 Setting \np{ln_grid_global}{ln\_grid\_global} means that the code distributes the observations evenly between processors. 105 105 Alternatively each processor will work with observations located within the model subdomain 106 106 (see \autoref{subsec:OBS_parallel}). … … 565 565 (for surface observation types only). 566 566 567 The main namelist option associated with the interpolation/averaging is \np{nn \_2dint}.567 The main namelist option associated with the interpolation/averaging is \np{nn_2dint}{nn\_2dint}. 568 568 This default option can be set to values from 0 to 6. 569 569 Values between 0 to 4 are associated with interpolation while values 5 or 6 are associated with averaging. 570 570 \begin{itemize} 571 \item \np{nn \_2dint}\forcode{ = 0}: Distance-weighted interpolation572 \item \np{nn \_2dint}\forcode{ = 1}: Distance-weighted interpolation (small angle)573 \item \np{nn \_2dint}\forcode{ = 2}: Bilinear interpolation (geographical grid)574 \item \np{nn \_2dint}\forcode{ = 3}: Bilinear remapping interpolation (general grid)575 \item \np{nn \_2dint}\forcode{ = 4}: Polynomial interpolation576 \item \np{nn \_2dint}\forcode{ = 5}: Radial footprint averaging with diameter specified in the namelist as571 \item \np{nn_2dint}{nn\_2dint}\forcode{ = 0}: Distance-weighted interpolation 572 \item \np{nn_2dint}{nn\_2dint}\forcode{ = 1}: Distance-weighted interpolation (small angle) 573 \item \np{nn_2dint}{nn\_2dint}\forcode{ = 2}: Bilinear interpolation (geographical grid) 574 \item \np{nn_2dint}{nn\_2dint}\forcode{ = 3}: Bilinear remapping interpolation (general grid) 575 \item \np{nn_2dint}{nn\_2dint}\forcode{ = 4}: Polynomial interpolation 576 \item \np{nn_2dint}{nn\_2dint}\forcode{ = 5}: Radial footprint averaging with diameter specified in the namelist as 577 577 \texttt{rn\_[var]\_avglamscl} in degrees or metres (set using \texttt{ln\_[var]\_fp\_indegs}) 578 \item \np{nn \_2dint}\forcode{ = 6}: Rectangular footprint averaging with E/W and N/S size specified in578 \item \np{nn_2dint}{nn\_2dint}\forcode{ = 6}: Rectangular footprint averaging with E/W and N/S size specified in 579 579 the namelist as \texttt{rn\_[var]\_avglamscl} and \texttt{rn\_[var]\_avgphiscl} in degrees or metres 580 580 (set using \texttt{ln\_[var]\_fp\_indegs}) … … 582 582 Replace \texttt{[var]} in the last two options with the observation type (sla, sst, sss or sic) for 583 583 which the averaging is to be performed (see namelist example above). 584 The \np{nn \_2dint} default option can be overridden for surface observation types using584 The \np{nn_2dint}{nn\_2dint} default option can be overridden for surface observation types using 585 585 namelist values \texttt{nn\_2dint\_[var]} where \texttt{[var]} is the observation type. 586 586
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