Changeset 11314

Timestamp:

2019-07-19T19:04:20+02:00 (5 years ago)

Author:

djlea

Message:

#2297 Updates in response the P Mathiot's review

Location:

NEMO/branches/2019/dev_r11233_obsasm_docfixes/doc/latex/NEMO/subfiles

Files:

• chap_ASM.tex (modified) (3 diffs)
• chap_OBS.tex (modified) (1 diff)

NEMO/branches/2019/dev_r11233_obsasm_docfixes/doc/latex/NEMO/subfiles/chap_ASM.tex

@@ -100 +100 @@
 \label{sec:ASM_div_dmp}
 
-The velocity increments may be initialized by the iterative application of a divergence damping operator.
-In iteration step $n$ new estimates of velocity increments $u^{n}_I$ and $v^{n}_I$ are updated by:
+It is quite challenging for data assimilation systems to provide non-divergent velocity increments.
+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}.
+
+In iteration step $n$ (starting at $n=1$) new estimates of velocity increments $u^{n}_I$ and $v^{n}_I$ are updated by:
+
 \begin{equation}
   \label{eq:asm_dmp}
@@ -113 +116 @@
   \right.,
 \end{equation}
+
 where the divergence is defined as
+
 \[
   % \label{eq:asm_div}
@@ -120 +125 @@
       +\delta_j \left[ {e_{1v}\,e_{3v}\,v^{n-1}_I} \right]} \right).
 \]
+
 By the application of \autoref{eq:asm_dmp} the divergence is filtered in each iteration,
 and the vorticity is left unchanged.

NEMO/branches/2019/dev_r11233_obsasm_docfixes/doc/latex/NEMO/subfiles/chap_OBS.tex

@@ -677 +677 @@
 \item The standard grid-searching code is used to find the nearest model grid point to the observation location
   (see next subsection).
-\item The maximum number of grid points is calculated in the local grid domain for which
-  the averaging is likely need to cover.
+\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.
 \item The longitudes and latitudes of the grid points surrounding the nearest model grid box are extracted using
   existing MPI routines.