Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy with the WRF-Hydro modeling system Alfonso Senatore • CeSMMA - Centro Studi per il Monitoraggio e la Modellazione Ambientale • Dept. of Environmental and Chemical Engineering, University of Calabria Padua, September 23, 2015
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Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy with the WRF-Hydro modeling system
Alfonso Senatore
• CeSMMA - Centro Studi per il Monitoraggio e la Modellazione Ambientale • Dept. of Environmental and Chemical Engineering, University of Calabria
Padua, September 23, 2015
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Objectives / Outline 1. Reliability of stand-‐alone WRF-‐Hydro hydrological model in a Mediterranean catchment (comparison of observed and simulated streamflow)
2. Parameterization and evaluation of stand-‐alone WRF mesoscale model, with particular reference to precipitation
3. Comparison of stand-‐alone WRF modeling system with fully coupled WRF/WRF-‐Hydro modeling system
� Evaluating potential of fully coupled modeling, both for hydrometeorological forecasts (short-‐medium range) and hydrological impacts due to climate change (long-‐range)
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Scientific motivation
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Atlantic weather fronts
~ 2000 mm ~ 500 mm
~ 35 km
Study area
Crotone
Soverato Vibo
Sybaris
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
5 hours
160 mm
Study area
Crotone
Soverato Vibo
Sybaris Corigliano/Rossano 12.08.2015
Platì 106 mm
Reggio C. province
09.09.2015
San Luca 115 mm
Sant’Agata 113 mm
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
“Crati @ S. Sofia” gauging station 1281 km2 250 m horizontal resolution Hmax = 1856 m Hmean = 672 m Hmin = 49 m
mean precipitation 1200 mm mean temperature 11.9 °C
• Flexible coupling architecture designed to be extensible to new hydrological parameterizations
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Subsurface routing • Quasi steady-‐state, Boussinesq flow model •Exfiltration from fully-‐saturated soil columns •Anisotropy in vertical and horizontal Ksat •No ‘perched’ flow •Soil depth is uniform • Critical initialization value: water table depth
WRF-Hydro
Credits: D
avid J. Goc
his, NCAR
Basic concepts • Linking the column structure of land surface models with the ‘distributed’ structure of hydrological models
• Flexible coupling architecture designed to be extensible to new hydrological parameterizations
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
WRF-Hydro
Credits: D
avid J. Goc
his, NCAR
Channel routing • Solution Methods: –Gridded: 1-‐d diffusive wave: fully-‐unsteady, explicit, finite-‐difference –Reach: Muskingam, Muskingam-‐Cunge • A priori function of Strahler order • Trapezoidal channel (bottom width, side slope)
Basic concepts • Linking the column structure of land surface models with the ‘distributed’ structure of hydrological models
• Flexible coupling architecture designed to be extensible to new hydrological parameterizations
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Methodology
Stand-‐alone WRF-‐HYDRO with observed forcing
Oct,1s
t 2
002
Nov
,1st
Dec,1s
t
Feb,1st
Mar,1s
t
Apr,1s
t
May,1s
t
Jun,1st
Jul,1
st
Aug
,1st
Sep,1st
Jan,1st 200
3
Oct,1s
t 2
003
Jan, 6
WRF-‐only
Fully-‐coupled WRF-‐HYDRO
Oct,1st 2005
Oct,1st 2005
1.
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Stand-alone WRF-Hydro Noah LSM
2.5 km res
à 250 m
à 2.5 km
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
� Calibration procedure
Stand-alone WRF-Hydro
www.pesthomepage.org
Minimization of the objective function Φ, given by the sum of squared deviations between model-‐generated observations and experimental observations, by means of the Gauss-‐Marquardt-‐Levenberg method (non-‐linear estimation technique)
Hourly streamflow � Experimental observations?
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Stand-alone WRF-Hydro � Parameters involved in the calibration process
Several (dozens!) preliminary simulations in order to understand sensitivity of the model to single parameters and stepwise approach for the calibration of the parameters controlling water volume (1st step) and hydrograph shape (2nd step)
• 4 Manning roughness coefficients (CHANPARM.TBL) • Bucket model exponent (GWBUCKPARM.TBL ) • Slope coefficient modifying the drainage out the bottom of the last soil layer (GENPARM.TBL)
• Ksat for sandy loam (most diffused texture in the basin) (SOILPARM.TBL) • depth of the bottom of the first soil layer (namelist.hrldas, hydro.namelist) • gridded values of the overland flow roughness scaling factor (OVROUGHRTFAC)
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
� Jul 26, 2004 Results - precipitation
WRF WRF-‐Hydro
Western station
Eastern station
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
� Jul 26, 2004 Results - precipitation
IWV (kgm-‐2), sea level pressure (contours; hPa), and 10-‐m winds (barbs; ms-‐1) on 26 Jul 2004, 0900 UTC with a) WRF-‐only and b) fully-‐coupled WRF/WRF-‐Hydro simulations. c) Ts differences in the skin temperature for the two models (WRF-‐only minus fully-‐coupled WRF/WRF-‐Hydro) at the same date and time
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Results � Surface runoff (a) and deep drainage (b)
1068 mm
641 mm
893 mm
723 mm
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
� Soil moisture Results
ZSOIL(1) 0-‐0.05 m
ZSOIL(4) 0.7-‐1.5 m
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
H WRF (W m-‐2) 49.6 -‐1.0 50.6 102.0 43.6 WRF-‐Hydro (W m-‐2) 46.7 -‐1.2 49.2 95.5 40.0
λE WRF (W m-‐2) 49.8 22.0 72.9 70.9 24.0 WRF-‐Hydro (W m-‐2) 53.6 23.3 74.8 78.6 28.4
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Results � LE -‐ Aug 31, 2003, 13:00
WRF-‐only WRF-‐Hydro
Shannon enthropy (as a measure of spatial variability): • WRF = 0.83
• WRF-‐Hydro = 0.91
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Results � Soil moisture and fluxes validation?
Bonis FLUXNET
station Soil moisture Sensible heat flux
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Results � Soil moisture feedback on precipitation
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Results � Models vs. MODIS LST – Aug 31, 2003
WRF WRF-‐H
MODIS
Inland cells
WRF WRF-‐H MODIS µ 307.3 306.4 306.1 c.v. 0.0120 0.0124 0.0144 E 0.69 0.72 0.77
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Results � Streamflow
Total volumes at the outlet: 1426×106m3 1334×106m3 Observed WRF-‐Hydro
Ratio to precipitation: 0.36 0.34
Nash-‐Sutcliffe 0.27
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Conclusions (1/2)
� Reliability of stand-‐alone WRF-‐Hydro hydrological model in a Mediterranean catchment
� WRF vs. fully-‐coupled WRF-‐Hydro à differences due to soil water lateral redistribution and re-‐infiltration: � Largest differences for surface runoff and deep drainage � Soil moisture and heat fluxes differences (summertime λE 8 Wm-‐2)
� Slightly better performance for precipitation
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Conclusions (2/2)
� An answer not only to the question “if”, but also “to what extent” does the fully coupled modeling alter mesoscale model performance in terms of land surface variables and precipitation, at least in the analyzed region
� More evident improvements for continental interior regions (no flat areas / not too humid climate)?
� Results achieved mainly relevant to long-‐range simulations (short-‐term under investigation…)
Towards fully coupled atmosphere-hydrology model systems: long-range simulation in Southern Italy A. Senatore, University of Calabria
Acknowledgements: G. Mendicino (Unical), D.J. Gochis, Wei Yu, D.N. Yates (NCAR), H. Kunstmann, B. Fersch, T. Rummler (IMK-IFU)