Changes between Version 18 and Version 19 of Branches/Driver_Improvements

Timestamp:

2016-05-27T09:24:14+02:00 (8 years ago)

Author:

jpolcher

Comment:

--

Branches/Driver_Improvements

@@ -50 +50 @@
 
 
-The figure is especially meant to illustrate that the interpolation for fluxes assumes that the interval of validity of the fluxes at index ''n'' is assumed implicitly by readim2.f90 to be between ''n-1/2'' and ''n+1/2''.
+The upper panel of the figure is meant to illustrate that the interpolation for fluxes in all generality (here for fluxes valid over the forcing time step before the instantaneous values) will not produce an interpolated value at the same time as the scalar field. readdim2.f90 assumes implicitly that the interval of validity of the fluxes at index ''n'' are between ''n-1/2'' and ''n+1/2'' else the flux and scalar interpolations give results at different physical times.
 
 The following explanations will probably help understand the meaning of the interpolated values in physical time. Let us suppose ''itauin'' is exactly the middle of the interval ''n-1'' and ''n''.
-From figure 1 we can deduce the following :
-- ''Tair(itauin) = (Tair(n-1)+Tair(n))/2'' which will be valid at ''t(itauin) = (t(n-1)+t(n))/2'' thus the interpolated value is also exactly in the middle of the physical time interval.
-- ''LWdown(itauin) = (LWdown(n-1)+LWdown(n))/2'' which will be valid at ''t(itauin) = (t(n-2)+t(n))/2 = t(n-1)''. This is thus different from the time at which ''Tair(itauin)'' is valid. Exactly half a forcing time step away.
+From the upper panel of the figure we can deduce the following :
+- ''Tair(itauin) = (Tair(n-1)+Tair(n))/2'' will be valid at ''t(itauin) = (t(n-1)+t(n))/2'' thus the interpolated value is exactly in the middle of the physical time interval.
+- ''LWdown(itauin) = (LWdown(n-1)+LWdown(n))/2'' will be valid at ''t(itauin) = (t(n-2)+t(n))/2 = t(n-1)''. This is thus different from the time at which ''Tair(itauin)'' is valid. Exactly half a forcing time step away.
 
-This error does not occur only if the fluxes are averages centred on the time corresponding at which the scalars are valid. 
+The lower panel will show that this error '''does not occur''' only if, the fluxes are averages centred on the time corresponding at which the scalars are valid. 
 
 == Add an explicit time information within the forcing files ==