H214-04
Global Reach-level River Flood Reanalysis (1980-2019)
Wednesday, 16 December 2020: 19:12
Virtual
Ming Pan1, Yuan Yang2, Peirong Lin3, Hylke Beck1, Cedric H David4, Dai Yamazaki5, Hui Lu6, Kun Yang7, Yang Hong8 and Eric F Wood1, (1)Princeton University, Civil and Environmental Engineering, Princeton, NJ, United States, (2)Tsinghua University, Department of Hydraulic Engineering, Beijing, China, (3)Princeton University, Civil & Environmental Engineering, Princeton, NJ, United States, (4)Jet Propulsion Laboratory, Pasadena, CA, United States, (5)The University of Tokyo, Institute of Industrial Sciences, Tokyo, Japan, (6)Tsinghua University, Department of Earth System Science, Beijing, China, (7)Tsinghua University, Beijing, China, (8)School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, United States
Abstract:
Flood is the extreme upper tail of river hydrology that can happen within a much shorter time (hours to days) and smaller area (a few river reaches) than other hydroclimatic hazards like droughts and hurricanes. Plus, flood has a wide geographic distribution globally. These natures make it harder to capture and study floods. The lack of global long-term fine-scale (in both time and space) river discharge records has been the major hurdle for large scale flood research.
Building upon a series of recent breakthroughs in (a) long-term climate model reanalysis, (b) optimal precipitation estimation, (c) quantifying hydrology over ungauged basins, (d) global high-resolution hydrography, (e) hydrologic model calibration/bias correction, and (e) vector-based river routing, we develop a 3-hourly river discharge record globally for 2.94 million river reaches (median length 6.8 km) derived from 90-m topography during 1980-2019. The modeling chain consists of the VIC land surface model (5-km, 3-hourly) and RAPID routing model (2.94 million river/catchment vectors) with precipitation input from MSWEPv2 and meteorological fields downscaled from ERA5. VIC model calibration and bias-correction (post-processing) are conducted against the GSCD database. Flood events (above 2-year return period) and their characteristics are extracted. The estimated discharge and flood events are evaluated against 3-hourly flow records from 6000+ gauges in CONUS and daily records from 14000+ gauges globally. Analysis is performed on the breakdown of errors in model parameterization and precipitation forcing.
