Continental Scale hydro model inter-comparison for SWOT
Teleconference summary 2016 11 07
by Konstantinos M. Andreadis and Cédric H. DavidIn attendance
Ed Beighley,
Rodrigo Paiva,
Augusto Getirana,
George Allen,
Christine Lion,
Etienne Gaborit,
Colby Fisher,
Guy Schumann,
Dai Yamazaki,
Aaron Boone,
Patrick Lemoigne,
Kostas Andreadis,
Cedric David
Meeting minutes
Dai: presented the preliminary CaMa-FLOOD simulations over the Mississippi. CaMa-flood
has no treatment for lakes nor reservoirs. The framework is similar to that of MGB-IPH.
HydroSHEDS DEM data were used after hydrologic adjustment presented in Dai’s paper(2012, JoH). The 15-sec conditioned HydroSHEDS is actually not conditioned (manynegative slopes), this is why it needed to be smoothed (it is shared with the team on thewebsite). Quasi-2D river network (with channel bifurcation) is possible although not used
here. CaMa-FLOOD uses OpenMP for parallelization, 8 cores were used for thesesimulations. The same USGS gauges as Ed were used for comparison of results andobservations. VIC model outputs from NLDAS2 were used as input. Two types ofsimulations were run: one at 0.25 degrees, one at 0.1 degrees.
Cedric: I haven’t yet heard back from Bernhard Lehner about the 15-sec DEM inHydroSHEDS.
Augusto: How is the river depth obtained?
Dai: The river depth is extracted from conditioned DEM
Cedric: Are you simulating all rivers within a given grid box or just the largest one?
Dai: Only the largest river is simulated (so this is resolution-dependent).
Cedric: Could it be that your higher resolution shows slower flow wave propagation
because it seems that hydrographs are delayed at high resolution?Dai: My understanding is that there's more flooding at higher spatial resolution due tobetter resolving of floodplain.
Dai: what is the format for sharing model outputs with the team?
Cedric: Let’s use a CSV file to share simulation results. One row per daily value, one columb
per station, header with USGS gauge number and HydroSHEDS ARCID. I will make atemplate.
Dai: Shall we all use the same modified DEM?
Rodrigo: That’s probably a good idea, but let’s wait for everybody to have performed theirsimulations just in case we need to make further modifications to the DEM before running
new simulations.
Dai: There is possible uncertainty in different routines for hillslope routing. Perhaps needto assess these?
Cedric: the operational version of NLDAS uses Lohman routing model. Probably ok to lump
all water from the surface and subsurface directly in the rivers without accounting forhorizontal surface/subsurface routing outside of the river network. Ed might be able toswitch this option on and off on HRR, but not all of us can.
Ed: That’s correct, HRR can do that.
Dai: Other news from the Univ. of Tokyo: we have developed a global data assimilation
scheme for CaMa-flood (see poster at AGU), and we have developed a new global DEM (talkat AGU). New DEM data will become available in the near future.
Cedric: You showed a lot of flooding downstream, which is not apparent in observations
probably due to existing man-made structures. This is similar to what Rodrigo presented.
Did you look at the discharge hydrographs to see if they are similarly dampened comparedto observations?
Dai: I haven’t looked into that yet.
Augusto: NLDAS land surface models are quite old, runoff results will change considerablywith new LSMs.
Cedric: We’ll be happy to leverage new NLDAS data when they become available.
Augusto: How are USGS stations selected? There are many others that could be used.
Cedric: The stations selected mirror that used in my 2015 WRR paper (choice was based on
full daily data availability, and gauges selected upstream and downstream of major
confluences).

Cedric: Hyungjun proposes to host our Working Group meeting in Tokyo, parallel toanother ongoing meeting (HESSS-4: Hydrology delivers Earth System Science to Society, 4thmeeting) on 15-19 May 2017, which will happen the week before the joint AGU Spring
Meeting/JPGU meeting.
Aaron: This is likely being co-organized with GLASS/GEWEX and ISI-MIP. I’ll be there but
I’m not sure I’ll be available because of my other commitments to that meeting.
Cedric: Actually, that meeting is scheduled for the mornings, and we would have side
sessions the three afternoons.
Cedric: We look forward to seeing everybody at AGU. I will use some of your graphs for theposter, thank you in advance for your contribution! Let’s have a Happy Hour meeting atAGU: Wed Dec 14 at 6pm.
Cedric: Volunteers for next time? How about Augusto and Kostas?
Kostas/Augusto: I should be able to show some very preliminary results.
Action items
Cedric: reach out to Bernhard Lehner again.
Cedric: provide a template of how model outputs should be shared by all people runningmodels.
Cedric: next phone call ~ Monday December 05.
Cedric: plan happy: hour: Wed Dec 14, 6pm, Owl Tree - 601 Post St San Francisco, CA94109.
Augusto: will present preliminary HyMAP results.
Kostas: will present preliminary LISFLOOD results.