Changeset 2197 for branches/DEV_r1826_DOC/DOC/TexFiles/Chapters/Chap_SBC.tex

Timestamp:

2010-10-10T15:44:41+02:00 (14 years ago)

Author:

gm

Message:

ticket:#658 in LDF, add the mixed lap-bilap doc see ticket:659

File:

• branches/DEV_r1826_DOC/DOC/TexFiles/Chapters/Chap_SBC.tex (modified) (4 diffs)

branches/DEV_r1826_DOC/DOC/TexFiles/Chapters/Chap_SBC.tex

@@ -373 +373 @@
 
 
-To do this we need to treat evaporation/precipitation fluxes and river runoff differently in the \mdl{tra\_sbc} module.  We decided to separate them throughout the code, so that the variable emp represented solely evaporation minus precipitation fluxes, and a new 2d variable rnf was added which represents the volume flux of river runoff (in kg/m2s to remain consistent with emp).  This meant many uses of emp and emps needed to be changed, a list of all modules which use emp or emps and the changes made are below:
+To do this we need to treat evaporation/precipitation fluxes and river runoff differently in the \mdl{tra\_sbc} module.  We decided to separate them throughout the code, so that the variable \textit{emp} represented solely evaporation minus precipitation fluxes, and a new 2d variable rnf was added which represents the volume flux of river runoff (in kg/m2s to remain consistent with emp).  This meant many uses of emp and emps needed to be changed, a list of all modules which use emp or emps and the changes made are below:
 
 
@@ -379 +379 @@
 
 It is convenient to introduce the river runoff in the model as a surface 
-fresh water flux. This is the defualt option within NEMO, and there is then
+fresh water flux. This is the default option within NEMO, and there is then
  the option for the user to increase vertical mixing in the vicinity of the rivermouth.
 
@@ -428 +428 @@
 }
 
+
+%>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+\begin{figure}[!t] \label{Fig_SBC_diurnal}  \begin{center}
+\includegraphics[width=0.8\textwidth]{./TexFiles/Figures/Fig_SBC_diurnal.pdf}
+\caption{Example of recontruction of the diurnal cycle variation of short wave flux  
+from daily mean values. The reconstructed diurnal cycle (red squares) is chosen 
+as the mid time step value of the analytically cycle (blue line), not as 
+the mean value of the analytical cycle over a time step (black line). 
+The misfit is however small and without systematic bias. From \citet{Bernie_al_CD07}.}
+\end{center}   \end{figure}
+%>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 % ================================================================
@@ -450 +461 @@
 in \NEMO by setting \np{ln\_dm2dc}=true (a \textit{namsbc} namelist parameter) when using 
 CORE bulk formulea (\np{ln\_blk\_core}=true) or the flux formulation (\np{ln\_flx}=true). 
-The algorithm used is detailed in the appendix~A of \cite{Bernie_al_CD07} 
-and illustrated on Fig.\ref{Fig_SBC_diurnal}. 
-
-Note that the reconstruction can change the daily mean value of SWF by a few tenth of 
-W/m$^2$ ($\pm 0.5$~W/m$^2$ with a 1~h sampling) but this is not a systematic bias. 
+The reconstruction is performed in the \mdl{sbcdcy} module. The detail of the algoritm used 
+can be found in the appendix~A of \cite{Bernie_al_CD07}. It is not a strictly conservative 
+algorithm as the mid time step analytical value is used instead of the mean value of 
+the analytical cycle over a time step (Fig.\ref{Fig_SBC_diurnal}). Nevertheless, the error is  
+quite small, reaching locally a maximum value of a few tenth of W/m$^2$ with a 2~h sampling, 
+the error decreasing with increasing the sampling. Moreover, the error is not a systematic, and 
+thus does not lead to seasonal bias. 
+           
+Fig.\ref{Fig_SBC_dcy} show an example of 12 reconstructed diurnal cycle, one every 2~hours 
+(from 1am to 11pm). The difference between the original daily mean and the daily mean 
+reconstructed diurnal cycle (not shown) is small (extrema of $\pm$0.4 W/m$^2$).
+
+%>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+\begin{figure}[!t] \label{Fig_SBC_dcy}  \begin{center}
+\includegraphics[width=0.7\textwidth]{./TexFiles/Figures/Fig_SBC_dcy.pdf}
+\caption{Example of recontruction of the diurnal cycle variation of short wave flux  
+from daily mean values on an ORCA2 grid with a time sampling of 2~hours (from 1am to 11pm). 
+The display is on (i,j) plane. }
+\end{center}   \end{figure}
+%>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
 Note also that the setting a diurnal cycle in SWF is highly recommended  when 
 the top layer thickness approach 1~m or less, otherwise large error in SST can 
 appear due to an inconsistency between the scale of the vertical resolution 
 and the forcing acting on that scale.
-
-%>>>>>>>>>>>>>>>>>>>>>>>>>>>>
-\begin{figure}[!t] \label{Fig_SBC_diurnal}  \begin{center}
-\includegraphics[width=1.0\textwidth]{./TexFiles/Figures/Fig_SBC_diurnal.pdf}
-\caption{Example of recontruction of the diurnal cycle variation of short wave flux  
-from daily mean values. From \citet{Bernie_al_CD07}.}
-\end{center}   \end{figure}
-%>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 % ================================================================