Changes between Version 16 and Version 17 of Branches/Driver_Improvements

Timestamp:

2016-05-27T09:13:47+02:00 (8 years ago)

Author:

jpolcher

Comment:

--

Branches/Driver_Improvements

@@ -52 +52 @@
 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 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.
+
+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 ==
 As described above, the driver of ORCHIDEE is relatively rigid because it makes strict assumptions one temporal specification for the forcing files. At first, we do not expect to develop a more flexible driver but we would like to add explicit time information in the driver in order to avoid misuse.