Changeset 2207 for branches/DEV_r2191_3partymerge2010/DOC/TexFiles/Chapters/Chap_SBC.tex

Timestamp:

2010-10-11T18:51:54+02:00 (14 years ago)

Author:

acc

Message:

#733 DEV_r2191_3partymerge2010. Merged in changes from devukmo2010 branch

File:

• branches/DEV_r2191_3partymerge2010/DOC/TexFiles/Chapters/Chap_SBC.tex (modified) (4 diffs)

branches/DEV_r2191_3partymerge2010/DOC/TexFiles/Chapters/Chap_SBC.tex

@@ -36 +36 @@
 term to observed SST and/or SSS (\np{ln\_ssr}=true); the modification of fluxes 
 below ice-covered areas (using observed ice-cover or a sea-ice model) 
-(\np{nn\_ice}=0,1, 2 or 3); the addition of river runoffs as surface freshwater 
-fluxes (\np{ln\_rnf}=true); the addition of a freshwater flux adjustment in 
+(\np{nn\_ice}=0,1, 2 or 3); the addition of river runoffs (\np{ln\_rnf}=true);
+ the addition of a freshwater flux adjustment in 
 order to avoid a mean sea-level drift (\np{nn\_fwb}= 0, 1 or 2); and the 
 transformation of the solar radiation (if provided as daily mean) into a diurnal 
@@ -163 +163 @@
 j-component of the surface current  & ssv\_m & $m.s^{-1}$   & V \\   \hline
 Sea surface temperature          & sst\_m & \r{}$K$      & T \\   \hline
-Sea surface salinty              & sss\_m & $psu$        & T \\   \hline
+Sea surface salinity             & sss\_m & $psu$        & T \\   \hline
 \end{tabular}
 \caption{Ocean variables provided by the ocean to the surface module (SBC). 
@@ -571 +571 @@
 %-------------------------------------------------------------------------------------------------------------
 
-The river runoffs 
-
 It is convenient to introduce the river runoff in the model as a surface 
-fresh water flux. 
-
+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.\\
 
 %Griffies:  River runoff generally enters the ocean at a nonzero depth rather than through the surface. Many global models, however, have traditionally inserted river runoff to the top model cell. Such can become problematic numerically and physically when the top grid cells are reÞned to levels common in coastal modelling. Hence, more applications are now considering the input of runoff throughout a nonzero depth. Likewise, sea ice can melt at depth, thus necessitating a mass transport to occur within the ocean between the liquid and solid water masses.
 
-\colorbox{yellow}{Nevertheless, Pb of vertical resolution and increase of Kz in vicinity of }
-
-\colorbox{yellow}{river mouths{\ldots}}
+%\colorbox{yellow}{Nevertheless, Pb of vertical resolution and increase of Kz in vicinity of }
+
+%\colorbox{yellow}{river mouths{\ldots}}
 
 %IF( ln_rnf ) THEN                                     ! increase diffusivity at rivers mouths
@@ -587 +585 @@
 %ENDIF
 
+However, this method is not very appropriate for coastal modelling.  As such its also possible
+ to specify, in a netcdf input file, the temperature and salinity of the river, along with the 
+depth (in metres) which the river should be added to.  This enables to river to be correctly 
+added through all or some of the water column, instead of as a surface flux, and also means 
+the temperature and salinity (for low salinity outflow) of the river impacts the surrounding ocean.
+
+For the river temperature variable, -999 is the missing data value and this causes river temperature 
+to be taken as the surface temperature at the river point.  For the depth parameter a value of -1 means the 
+river is added to the surface box only, and a value of -999 means the river is added through 
+the entire water column.
+
+Namelist options, \np{ln\_rnf\_depth}, \np{ln\_rnf\_sal} and \np{ln\_rnf\_temp} control whether 
+the river attributes (depth, salinity and temperature) are read in and used.  If these are set 
+as false the river is added to the surface box only, assumed to be fresh (0psu), and/or taken 
+as surface temperature respectively.
+
+It is also possible for runnoff to be specified as a negative value for modelling flow through 
+straits, ie, modelling the Baltic flow in and out of the north sea.  When the flow is out of the 
+domain there is no change in temperature and salinity, regardless of the namelist options used.
+
+The runoff value and attributes are read in in sbcrnf.  The mass/volume addition is added to the 
+divergence term in sbc\_rnf\_div.  The dilution effect of the river is automatically applied through 
+the vertical tracer advection, and the direct flux of tracers into the domain is done in trasbc.