Continental Scale hydro model inter-comparison for SWOT
Teleconference summary 2016 10 03by Cédric H. DavidIn attendance
Ed Beighley,
Rodrigo Paiva,
Ayan Santos Fleischmann,
Walter Collischonn,
Christine Lion,
Guy Schumann,
George Allen,
Dai Yamazaki,
Cedric David
Meeting minutes
Cedric: presented the website for the project http://rapid-hub.org/intercomparison.html
Ed: looks great!
Ed: presented the preliminary HRR simulations over the Mississippi. The hydrographic
network was re-derived from the HydroSHEDS conditioned DEM with a 100 grid cells (of15 arc-seconds each) threshold and matches perfectly with the HydroSHEDS vector
network. At this scale some actual river channels are not included and this has an influenceon the parameters to use in modeling. Channel and land surface roughness coefficientsused differ from experimental design table. Width and discharge data from Andreadis et al.
(2013). Mean slope from preconditioned DEM. Total basin area in Andreadis et al. differsfrom HydroSHEDS, but this may not be an issue since the dataset was calibrated to match
observations and since we’re not using the area from Andreadis et al. for simulations.
Length and areas computed using North America Albers Equal Area Conic. Correlations
and bias computed. Missouri Basin is an issue: model overestimates reality which is also
tampered by reservoirs.
Dai: Cedric, please add link to processed runoff data on website.
Cedric: Ed, what time zone did you use?
Ed: I wasn’t sure, so I ended up using Universal Time.
Cedric: it isn’t clear what the best approach is.
Rodrigo: presented the preliminary MGB simulations over the Mississippi that was done
along with Ayan Fleischmann and Walter Collischonn. Summarized the existingcapabilities of MGB. The land surface processes were not used for this particular study, per
the proposed experimental design. 16,000 catchments and associated river reaches(average size 10 km) were derived from HydroSHEDS preconditioned DEM. This meansthat some of the HydroSHEDS river reaches are not currently simulated by MGB. There ismore runoff in the east than the west of the Mississippi Basin. Runoff is predominantly
surface to the west, and subsurface to the east. Bankful width and depth from Andreadis etal. (2013). Bed elevation from HydroSHEDS DEM minus the bankful depth. Roughness inrivers is 0.03. Surface and baseflow parameters determined using Kirpich formula using
slope and length of major tributaries. Two types of equations used: Inertial model of Bateset al. (2010), and constant parameter Muskingum Cunge. With inertial equations, default
widths and depths from Andreadis et al. lead to flat hydrographs and enhanced flooding
mechanisms. However, using the 95 percentile values leads to more meaningful results.
With Muskingum Cunge, the problem is less evident. Also tried different time constants forrouting.
Guy: without flood defenses and reservoirs your inundation results are not bad, that’s what
you would expect naturally. Since it seems the group decided to go for a more "natural"simulation, i.e. no reservoirs, to make everyone's life easier as Cedric noted, I think for thisparticular test case we don't need to worry about this but I agree that it is a very importantissue. So in brief, does well also for inundation.
Action items
Cedric: add link to Dai’s preprocessed runoff data on experimental design table.
Cedric: next phone call ~ Monday November 07.
Dai: will present CaMa-Flood results.