Changeset 9393 for branches/2017/dev_merge_2017/DOC/tex_sub/chap_OBS.tex
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- 2018-03-13T15:00:56+01:00 (6 years ago)
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branches/2017/dev_merge_2017/DOC/tex_sub/chap_OBS.tex
r9392 r9393 4 4 % Chapter observation operator (OBS) 5 5 % ================================================================ 6 \chapter{Observation and model comparison (OBS)}6 \chapter{Observation and Model Comparison (OBS)} 7 7 \label{OBS} 8 8 … … 24 24 The OBS code is called from \mdl{nemogcm} for model initialisation and to calculate the model 25 25 equivalent values for observations on the 0th timestep. The code is then called again after 26 each timestep from \mdl{step}. The code is only activated if the namelist logical \np{ln _diaobs}26 each timestep from \mdl{step}. The code is only activated if the namelist logical \np{ln\_diaobs} 27 27 is set to true. 28 28 … … 34 34 Some profile observation types (e.g. tropical moored buoys) are made available as daily averaged quantities. 35 35 The observation operator code can be set-up to calculate the equivalent daily average model temperature fields 36 using the \np{nn _profdavtypes} namelist array. Some SST observations are equivalent to a night-time36 using the \np{nn\_profdavtypes} namelist array. Some SST observations are equivalent to a night-time 37 37 average value and the observation operator code can calculate equivalent night-time average model SST fields by 38 setting the namelist value \np{ln _sstnight} to true. Otherwise the model value from the nearest timestep to the38 setting the namelist value \np{ln\_sstnight} to true. Otherwise the model value from the nearest timestep to the 39 39 observation time is used. 40 40 … … 88 88 89 89 Options are defined through the \ngn{namobs} namelist variables. 90 The options \np{ln _t3d} and \np{ln_s3d} switch on the temperature and salinity90 The options \np{ln\_t3d} and \np{ln\_s3d} switch on the temperature and salinity 91 91 profile observation operator code. The filename or array of filenames are 92 specified using the \np{cn _profbfiles} variable. The model grid points for a92 specified using the \np{cn\_profbfiles} variable. The model grid points for a 93 93 particular observation latitude and longitude are found using the grid 94 94 searching part of the code. This can be expensive, particularly for large 95 numbers of observations, setting \np{ln _grid_search_lookup} allows the use of95 numbers of observations, setting \np{ln\_grid\_search\_lookup} allows the use of 96 96 a lookup table which is saved into an ``xypos`` file (or files). This will need 97 97 to be generated the first time if it does not exist in the run directory. 98 98 However, once produced it will significantly speed up future grid searches. 99 Setting \np{ln _grid_global} means that the code distributes the observations99 Setting \np{ln\_grid\_global} means that the code distributes the observations 100 100 evenly between processors. Alternatively each processor will work with 101 101 observations located within the model subdomain (see section~\ref{OBS_parallel}). … … 556 556 NEMO therefore has the capability to specify either an interpolation or an averaging (for surface observation types only). 557 557 558 The main namelist option associated with the interpolation/averaging is \np{nn _2dint}. This default option can be set to values from 0 to 6.558 The main namelist option associated with the interpolation/averaging is \np{nn\_2dint}. This default option can be set to values from 0 to 6. 559 559 Values between 0 to 4 are associated with interpolation while values 5 or 6 are associated with averaging. 560 560 \begin{itemize} 561 \item \ forcode{nn_2dint= 0}: Distance-weighted interpolation562 \item \ forcode{nn_2dint= 1}: Distance-weighted interpolation (small angle)563 \item \ forcode{nn_2dint= 2}: Bilinear interpolation (geographical grid)564 \item \ forcode{nn_2dint= 3}: Bilinear remapping interpolation (general grid)565 \item \ forcode{nn_2dint= 4}: Polynomial interpolation566 \item \ forcode{nn_2dint= 5}: Radial footprint averaging with diameter specified in the namelist as \np{rn\_???\_avglamscl} in degrees or metres (set using \np{ln\_???\_fp\_indegs})567 \item \ forcode{nn_2dint= 6}: Rectangular footprint averaging with E/W and N/S size specified in the namelist as \np{rn\_???\_avglamscl} and \np{rn\_???\_avgphiscl} in degrees or metres (set using \np{ln\_???\_fp\_indegs})561 \item \np{nn\_2dint}\forcode{ = 0}: Distance-weighted interpolation 562 \item \np{nn\_2dint}\forcode{ = 1}: Distance-weighted interpolation (small angle) 563 \item \np{nn\_2dint}\forcode{ = 2}: Bilinear interpolation (geographical grid) 564 \item \np{nn\_2dint}\forcode{ = 3}: Bilinear remapping interpolation (general grid) 565 \item \np{nn\_2dint}\forcode{ = 4}: Polynomial interpolation 566 \item \np{nn\_2dint}\forcode{ = 5}: Radial footprint averaging with diameter specified in the namelist as \np{rn\_???\_avglamscl} in degrees or metres (set using \np{ln\_???\_fp\_indegs}) 567 \item \np{nn\_2dint}\forcode{ = 6}: Rectangular footprint averaging with E/W and N/S size specified in the namelist as \np{rn\_???\_avglamscl} and \np{rn\_???\_avgphiscl} in degrees or metres (set using \np{ln\_???\_fp\_indegs}) 568 568 \end{itemize} 569 569 The ??? in the last two options indicate these options should be specified for each observation type for which the averaging is to be performed (see namelist example above). 570 The \np{nn _2dint} default option can be overridden for surface observation types using namelist values \np{nn\_2dint\_???} where ??? is one of sla,sst,sss,sic.570 The \np{nn\_2dint} default option can be overridden for surface observation types using namelist values \np{nn\_2dint\_???} where ??? is one of sla,sst,sss,sic. 571 571 572 572 Below is some more detail on the various options for interpolation and averaging available in NEMO. … … 956 956 957 957 The above namelist will result in feedback files whose first 12 hours contain 958 the first field of \ifile{foo}and the second 12 hours contain the second field.958 the first field of foo.nc and the second 12 hours contain the second field. 959 959 960 960 %\begin{framed} … … 988 988 989 989 %\begin{framed} 990 \textbf{Note: ln\_cl4} must be set to \ emph{.TRUE.} in \textbf{namobs}990 \textbf{Note: ln\_cl4} must be set to \forcode{.true.} in \textbf{namobs} 991 991 to use class 4 outputs. 992 992 %\end{framed} … … 998 998 \noindent 999 999 \linebreak 1000 \ ifile{\textbf{\$\{prefix\}\_\$\{yyyymmdd\}\_\$\{sys\}\_\$\{cfg\}\_\$\{vn\}\_\$\{kind\}\_\$\{nproc\}}}1000 \textbf{\$\{prefix\}\_\$\{yyyymmdd\}\_\$\{sys\}\_\$\{cfg\}\_\$\{vn\}\_\$\{kind\}\_\$\{nproc\}}.nc 1001 1001 1002 1002 \noindent … … 1182 1182 \newpage 1183 1183 1184 \section{Observation Utilities}1184 \section{Observation utilities} 1185 1185 \label{OBS_obsutils} 1186 1186 … … 1331 1331 \end{cmds} 1332 1332 1333 \subsection{ building the obstools}1333 \subsection{Building the obstools} 1334 1334 1335 1335 To build the obstools use in the tools directory use ./maketools -n OBSTOOLS -m [ARCH].
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