Changes between Version 31 and Version 32 of Branches/Driver_Improvements

Timestamp:

2016-06-03T11:40:39+02:00 (8 years ago)

Author:

jpolcher

Comment:

--

Branches/Driver_Improvements

@@ +1 @@
+
+[[PageOutline]] 
+
 = Improvements of the Driver of ORCHIDEE =
 
@@ -102 +105 @@
 
  
+= Comparison of the old and new drivers =
+
+ORCHIDEE has now 2 drivers which are quite different in their conception. As discussed above the temporal interpolation is a little of a challenge so it is worth verifying how well it is done bu both driver and how important the differences are. This effort is undertaken here.
+
+The issue is particularly critical with the global forcing which are available at 3 or 6 hour interval and any shift in the date attributed to them impacts the interpolation in time and the variables given to ORCHIDEE. This issue is largely attenuated for point forcing where atmospheric conditions are available at a frequency higher than hourly. Thus the test here are carried out over the 5 global forcing data sets which are currently available to the community :
+
+- CRU-NCEP : This is the NCEP re-analysis corrected by Nicolas Viovy using CRU data. The version 5.4 which is used here only has data all the 6 hours.
+- CSWP : is the forcing prepared by U Tokyo for the international GSWP excise and is based on C20C re-analysis of ECMWF.
+- PGF : Is the Princeton forcing prepared which combines the NCEP re-analysis, CRU and GPCC data.  
+- WFD : Based on ERA-40 an corrected in the same way as WFDEI (This is the WATCH data set).
+- WFDEI : Based on ERA-I and corrected by the UKMO using the independent CRU information (An evolution of the WATCH data set)
+
+== Modelling set-up ==
+
+The ORCHIDEE trunk version of May 2016 is used for these tests. All forcing are used at a 900s time-step and the model is configured to output through XIOS at this same time step. This ensures that all the post-processing done XIOS on the forcing variables ORCHIDEE outputs is negligible compared to the assumptions on the time axis in the forcing.
+
+From the forcing files a small region (lon=-10.3:5.3 lat=35.3:45.3) was extracted to reduce computing time and ensure that the original data set could easily be compared to the model output.
+
+CRU-NCEP, WFD and WFDEI came already with the attributes describing the time averaging of the fluxes set. Two cases are distinguished there and they are :
+- Fluxes : time: mean(end) (SWdown LWdown Rainf Snowf)
+- Scalar : time: instantaneous (Tair Qair PSurf Wind)
+
+For GSWP and PGF this information was added after extracting the region of interest with the following commands :
+- GSWP Fluxes : 
+{{{
+        for v in $FLUX ; do
+            ncatted -h -a cell_methods,$v,o,c,"time: mean(center)" ES_GSWP3_${i}.nc
+        done
+}}}
+ 
+- GSWP Scalar : 
+
+{{{
+        for v in $SCALAR ; do
+            ncatted -h -a cell_methods,$v,o,c,"time: instantaneous" ES_GSWP3_${i}.nc
+        done
+}}}
+
+- PGF Fluxes :
+
+{{{
+        for v in $FLUX ; do
+            ncatted -h -a cell_methods,$v,o,c,"time: mean(start)" ES_PGF_${i}.nc
+        done
+}}}
+
+- PGF Scalar : 
+
+{{{
+        for v in $SCALAR ; do
+            ncatted -h -a cell_methods,$v,o,c,"time: instantaneous" ES_PGF_${i}.nc
+        done
+}}}
+
+Furthermore for the fluxes in GSWP we tested all three possible hypothesis :
+- GSWPe : "time: mean(end)"
+- GSWPc : "time: mean(center)"
+- GSWMs : "time: mean(start)"
+
+== Analysis ==
+
+== Results ==
+
+- WFDEI
+- WFD
+- CRU-NCEP
+- GSWP
+- PGF
+
+== Conclusions ==
 
 
-