Changeset 11314
 Timestamp:
 20190719T19:04:20+02:00 (4 years ago)
 Location:
 NEMO/branches/2019/dev_r11233_obsasm_docfixes/doc/latex/NEMO/subfiles
 Files:

 2 edited
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NEMO/branches/2019/dev_r11233_obsasm_docfixes/doc/latex/NEMO/subfiles/chap_ASM.tex
r11311 r11314 100 100 \label{sec:ASM_div_dmp} 101 101 102 The velocity increments may be initialized by the iterative application of a divergence damping operator. 103 In iteration step $n$ new estimates of velocity increments $u^{n}_I$ and $v^{n}_I$ are updated by: 102 It is quite challenging for data assimilation systems to provide nondivergent velocity increments. 103 Applying divergent velocity increments will likely cause spurious vertical velocities in the model. This section describes a method to take velocity increments provided to \NEMO ($u^0_I$ and $v^0_I$) and adjust them by the iterative application of a divergence damping operator. The method is also described in \citet{dobricic.pinardi.ea_OS07}. 104 105 In iteration step $n$ (starting at $n=1$) new estimates of velocity increments $u^{n}_I$ and $v^{n}_I$ are updated by: 106 104 107 \begin{equation} 105 108 \label{eq:asm_dmp} … … 113 116 \right., 114 117 \end{equation} 118 115 119 where the divergence is defined as 120 116 121 \[ 117 122 % \label{eq:asm_div} … … 120 125 +\delta_j \left[ {e_{1v}\,e_{3v}\,v^{n1}_I} \right]} \right). 121 126 \] 127 122 128 By the application of \autoref{eq:asm_dmp} the divergence is filtered in each iteration, 123 129 and the vorticity is left unchanged. 
NEMO/branches/2019/dev_r11233_obsasm_docfixes/doc/latex/NEMO/subfiles/chap_OBS.tex
r11311 r11314 677 677 \item The standard gridsearching code is used to find the nearest model grid point to the observation location 678 678 (see next subsection). 679 \item The maximum number of grid points is calculated in the local grid domain for which 680 the averaging is likely need to cover. 679 \item The maximum number of grid points required for that observation in each local grid domain is calculated. Some of these points may later turn out to have zero weight depending on the shape of the footprint. 681 680 \item The longitudes and latitudes of the grid points surrounding the nearest model grid box are extracted using 682 681 existing MPI routines.
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