The PREVAH-Modelling-System
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Massimiliano Zappa - WSL Daniel Viviroli - GIUB Joachim Gurtz - IACETH PowerPoint PPT Presentation


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The PREVAH-Modelling-System P recipitation- R unoff- Eva potranspiration H RU related Model (1993-2012). Massimiliano Zappa - WSL Daniel Viviroli - GIUB Joachim Gurtz - IACETH. Current developers: Dr. Massimiliano Zappa, [email protected]

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Massimiliano Zappa - WSL Daniel Viviroli - GIUB Joachim Gurtz - IACETH

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The PREVAH-Modelling-System

Precipitation-Runoff-Evapotranspiration HRU related Model (1993-2012)

Massimiliano Zappa - WSL

Daniel Viviroli - GIUB

Joachim Gurtz - IACETH

Current developers:

Dr. Massimiliano Zappa, [email protected]

Dipl. Geogr. Daniel Viviroli, [email protected]


The PREVAH-Modelling-System

Precipitation-Runoff-Evapotranspiration HRU related Model

PREVAH is / has ...

... a spatially distributed hydrological response units related watershed model

... a strongly conceptual description of the processes governing runoff generation

... flexibly manageable from the computational viewpoint

... designed to have modular structure allowing the use of different sub-models with different degree of complexly according to the avaialbility of input data.


The PREVAH-Modelling-System

Precipitation-Runoff-Evapotranspiration HRU related Model

PREVAH ...

... offers a users friendly set of tools for the pre-processing of the required physiogeographical, meteorological and hydrological data

...can provide a continuous simulation of discharge hydrographs including low flows and floods

...is able to provide spatially distributed data of runoff generation and of the most relevant storage elements of the surface hydrological cycle

...can be used at different spatial scales and can be coupled to different kinds of numerical models


The PREVAH-Modelling-System

Precipitation-Runoff-Evapotranspiration HRU related Model

Interpolated meteorology

precipitation, air temperature, global radiation, water vapour pressure,sunshine duration

Spatial information

Elevation, Aspect, Landuse, Slope, Soil Properties, ...

PREVAH

HRU-Table

Precipitation correction

Sevruk (1986)

Schulla (1997)

Monteith (1975)

Wendling (1975)

Zappa et al. (2003)

Menzel (1997)

Gurtz et al. (2003)

Site adjustment of radiation and temperature

Evapotranspiration

1 hour

or

1 day

GIS - Grids

Snowmelt / Icemelt

Interception

Soil moisture

Runoff generation

Calibration and Verification


The PREVAH-Modelling-System

Viviroli et al., 2007


VIEWOPTIM / DOTTYPLOT - Evaluation of calibration runs

PREVAH built-in semi automatic calibration

PREVAH built-in MONTE-CARLO calibration routine


Required meteorological variables - data availability in Switzerland

Precipitation[mm]

Air temperature[°C]

Global radiation[W/m2]

Wind speed[m/s]

Sunshine duration[-]

Relative humidity [-]


WINMET - Interpolation of meteorological data

Processing of data from Datawizard and generation of the meteorological input as required by PREVAH

Results: Tables with meteorological information for each defined meteorological sub-unit. Data are assimilated and processed by PREVAH during each model run


WINMET - Selection of stations


WINMET - Selection of stations

ANETZ

Climatological

Pluvimeters

hourly

2–3 × daily

1 × daily


WINMET - Selection of stations

ANETZ

Climate

Pluvios


Radar precipitation measurement in the AlpsCourtesy from Urs Germann, MeteoSwiss

Red hues >40mm/h

138 Gauges

1 Radar

300 km


701-1250-00Hydrological processes and modelling

PREVAH - calibration and verification

Massimiliano Zappa

Swiss Federal Research Institute WSL (Switzerland)


Calibration of PREVAH

MODEL PARAMETERS

Viviroli 2007


Initial

Period

(IP)

Calibration period

Validation period

Validation period (VP)

Calibration period

IP

VP1

Calibration period

Validation period 2

IP

1 yr

Basics on calibration (and verification)

  •  hydrological models contain sets of parameters (k!) which might be adjusted:

    • to adapt the model to the area under investigation

    • to fit empirical concepts

  • available data sets should be divided into two not overlapping periods called:

    • calibration period (adjustment of parameters)

    • validation period (no further adjustment – only verification)

  • Some models request a starting period (initial period):

    - to fill up the initially empty storages (reservoirs) and

    - to reach a first equilibrium between all its components

GIUB 2008


Automatic calibration of PREVAH

Viviroli 2007


Automatic calibration of PREVAH - search strategy

Viviroli 2007


Automatic calibration of PREVAH - recursive

...

Viviroli 2007


Automatic calibration of PREVAH

Default parameter-pairs for automatic calibration of PREVAH for Swiss glaciated catchments.


Automatic calibration of PREVAH - scores

Nine scores are derived from the application of equations determining E2, E2log, DV

to observed (Oi) and simulated (Si) data. The first three scores are determined by computing equations the three equations for the full calibration period. Six additional scores are introduced to improving the identification of robust parameter sets that provide a similar agreement for all the different seasons of the year and for all the years of the calibration period. Three scores are obtained by determining the standard deviation in the agreement between the single calibration years. Three more scores are determined by computing the standard deviation in the agreement of the twelve scores from the monthly sub-samples.

All nine scores are reduced to a dimensionless index ranging between zero and one. The nine indexes are finally combined by adopting a weighted geometric mean. The weights can be defined by the user, who can for instance decide if the calibration procedure as to be more focused on achieving high E2, a low DVor a well balanced mixture of all nine indexes.


Automatic calibration of PREVAH - animation

Viviroli 2007


Automatic calibration of PREVAH - evaluation

Discharge, linear

(MQ, HQ)

Discharge, logarithmic

(NQ)

Error in water balance

Total skill of the model


Automatic calibration of PREVAH - scores

Total skill of the model


Previous to each model run all tunable parameters a selected randomly.

Parameter distribution functions or parameter ranges are defined in order to constict the random sampling

Scores (likelihoods) are computed as for the automatic (iterative) calibration.

Advantages:

Objective method

Optima can be found in the whole parameter space.

The "global optimum" can be identified

Uncertainty in the parameter estimation is well declared

Drawbacks:

Very inneficient (non realistic parameter combinations

are tested as-well)

Large CPU-reqirments needed (10param runs!)

Monte-Carlo simulations

Viviroli 2007


Monte-Carlo simulations - examples

Allenbach–Adelboden, 50'000 model runs with random sampling of the tunable parameters

Viviroli 2007


Monte-Carlo simulations - examples

"Very inefficient" (Example Allenbach–Adelboden):

49% of the parameter sets have Nash-Values < 0

86% of the parameter sets have Nash-Values < 0.5

Viviroli 2007


Multiple response verification

The comparison of different outputs of a model run with selected observed variables allows a multiple-response verification of the model capabilities.

Watershed models can be verified against

...soil moisture observations (Time Domain Reflectory) -> local

...water balance components from a weighting lysimeter -> local

...latent heat flux (Bowen Ratio, eddy correlation) -> local

...snow depth and snow water equivalent data -> local

...discharge data -> integral

...remotely sensed data of snow cover patterns -> 2D

...tracers, Natural Isotopes -> integral

...qualitative und quantitative 'Soft-Data' -> integral/local


Hochwassersteuerung Sihlsee

MODUL 1 – Zuflussstatistik, PREVAH-Simulationen

Sihlsee-Staumauer, www.sihlsee.ch.vu, Markus Bernet


Kalibration Seezufluss – Auflösung 100x100 m

Landnutzung Gefälle


Kalibration Seezufluss – Auflösung 100x100 m

Teilgebiete Hohenstufen


Kalibration Seezufluss – Basis Zuflüsse ScherrerAG, Tageswerte

Input: MCH Stundenwerte/Tageswerte, 1999-2005

Aug - 2005


Kalibration Seezufluss – Basis Zuflüsse ScherrerAG, Tageswerte

Input: MCH Stundenwerte/Tageswerte, 1999-2011

2007

Okt -2011


Zuflussstatistik – Tagessummen Mio m3

ScherrerAG

PREVAH


Zufluss in Mio m3- Extremwertstatistik

72-Stundensummen

120-Stundensummen

ScherrerAG

PREVAH

ScherrerAG

PREVAH

Grössenordnung: 888.7 bis 888.34 ~ 7 Mio m3


Zuflussstatistik – Tagessummen Mio m3

ScherrerAG

PREVAH


Niederschlag und direkten Abfluss in Mio m3-

gleitenden 72-Stundensummen


Niederschlag und direkten Abfluss in Mio m3-

gleitenden 72-Stundensummen mit Abflusskoeffizient


Niederschlag und direkten Abfluss in Mio m3- Extremwertstatistik

72-Stundensummen

24-Stundensummen

Grössenordnung: 888.7 bis 888.34 ~ 7 Mio m3


Ereginis 2005, Stundenwerte


Ereginis 2005, Stundenwerte


Ereginis 1999, Stundenwerte (PREVAH) und Mix (Scherrer)


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