Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

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Storm Surge Network Forum Venice, 18-20 November 2013 Storm Surge modelling in Venice and the Mediterranean Sea: Improving the forecast tuning ECMWF wind fields Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2) (1) - ISMAR-CNR, Venezia (2) - ISAC-CNR, Padova

description

Storm Surge modelling in Venice and the Mediterranean Sea: Improving the forecast tuning ECMWF wind fields. Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2) (1) - ISMAR-CNR, Venezia (2) - ISAC-CNR, Padova. Operational SHYFEM-based systems. - PowerPoint PPT Presentation

Transcript of Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Page 1: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Storm Surge modelling in Venice and the Mediterranean Sea:

Improving the forecast tuning ECMWF wind fields

Marco Bajo(1), Stefano Zecchetto(2), Georg Umgiesser(1), Francesco De Biasio(2)

(1) - ISMAR-CNR, Venezia(2) - ISAC-CNR, Padova

Page 2: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Operational SHYFEM-based systems

Storm surge + total sea level inside the Venice lagoon:- ICPSM model (since 2003) : neural network post-processing- ISPRA model (since 2011): data assimilation (4D-PSAS) with data from 9 stations

Total sea level + waves on Mediterranean and Black Sea:- Kassandra (since 2010)

Page 3: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Storm Surge Forecast System for the Mediterranean Sea

The models is operational from May 2010. Information, results and forecasts can be found under:

http://www.ismar.cnr.it/kassandra

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Storm Surge Network Forum Venice, 18-20 November 2013

80002 nodes143286 elements

Resolution:• open sea 15-20 km• coast 5 km• Italian coast 1 km

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Storm Surge Network Forum Venice, 18-20 November 2013

eSurge Venice

eSurge-Venice (ESA Storm Surge for Venice) is a project funded by the European Space Agency, part of its Data User Element (DUE) programme. It aims to increase the usage of Earth Observation (EO) satellite data, from both ESA and other spacecraft, within the storm surge community.

www.esurge-venice.eu

Introduction

Page 6: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Storm surges in Venice

Introduction

Sea level Flooded pavement ratio

190 cm 88%

140 cm 59%

130 cm 46%

120 cm 28%

110 cm 12%

100 cm 5%

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Storm Surge Network Forum Venice, 18-20 November 2013

Satellite data

ALTIMETER DATA: to improve the initial state of the storm surge model, using data assimilation techniques or other methods.

SCATTEROMETER DATA: to improve the wind forcing of the storm surge model, looking for a tuning of the modelled wind.

Introduction

Page 8: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Correction of the wind fields

wc = we + (Δw/ws) we

θc = θe + Δθ

ECMWF wind speed (we) was tuned using

scatterometer data (ws):

(ws-we)/ws, averaged

over a specific time window around each SEV.

A similar method was used to obtain a field Δθ, for the directions:

Methods

Page 9: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

SEV list12 SEVs recorded in Venice from 2010 to 2012 were considered.

Methods

SEV 2010-02-28SEV 2010-11-10SEV 2010-11-19SEV 2010-11-21SEV 2010-11-26SEV 2010-12-23

SEV 2011-02-16

SEV 2012-10-27SEV 2012-10-31SEV 2012-11-02SEV 2012-11-11SEV 2012-11-28

Venice

Acqua AltaPlatform

Page 10: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Methods

Wind forcing

From the 0.125 degree wind and pressure fields, 0.25 and 0.5 degree fields were sub-sampled, in order to investigate the importance of the resolution.

For each SEV the original and the tuned fields were tested.

A total of 6 simulations were carried on for each SEV. First 10 days are considered spin-up time.

Page 11: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

The model uses the wind stress (Liu et al., 1979), which was computed using the ECMWF air density fields, the wind fields and the drag coefficient C

d fields. These depend also on the

wind correction.

Hydrodynamic model

A finite element model, solving the shallow water equations (SHYFEM) was used to run the hydrodynamic simulations.This model runs operationally every day at the storm surge forecasting and warning Centre in Venice (ICPSM).

Methods

Page 12: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Methods

Computational grid used by the model:- open boundary in the Gibraltar Strait;- only wind and pressure forcings;- sea level in the Acqua Alta Platform are used to run a second simulation inside the Venice Lagoon.

Acqua AltaPlatform

Mediterranean Sea

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Storm Surge Network Forum Venice, 18-20 November 2013

CASE 1: SEV 2010-11-26Results

Page 14: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Normalised bias Δw/wscat between ASCAT and ECMWF related to a selected SEV for the Mediterranean Sea.

Quickscat vs ECMWF

Results

SEV 2010-11-26

Page 15: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Statistics of the tuned data shows more directionality and higher wind speeds.

Speed Direction

Results

SEV 2010-11-26Quickscat vs ECMWF

Page 16: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Results

SEV 2010-11-26

OriginalTuned

Page 17: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Results

CASE 2: SEV 2012-11-11

Page 18: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Results

SEV 2012-11-11

OriginalTuned

Page 19: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Results

Statistics

OriginalTuned

Errors on maximum peaks

Page 20: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Skew surge

ObservedOriginalTuned

Page 21: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Results

Average statistics

Resolution RMSE [m] Correlation Peak error [m]

Original data

0.125 0.072 0.908 -0.102

0.25 0.072 0.906 -0.102

0.5 0.073 0.904 -0.104

Tuned data

0.125 0.066 0.918 -0.062

0.25 0.066 0.917 -0.063

0.5 0.067 0.915 -0.067

Page 22: Marco Bajo (1) , Stefano Zecchetto (2) , Georg Umgiesser (1) , Francesco De Biasio (2)

Storm Surge Network Forum Venice, 18-20 November 2013

Conclusions

Spatial wind resolution seems to have a low importance in the storm surge forecast in the Adriatic Sea. Until 0.5 degree grid size the performances are similar.

Tuned wind fields improve statistics

What about temporal resolution?

Better reproduction of the storm surge peaks. The improvement is higher with storm conditions.

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Storm Surge Network Forum Venice, 18-20 November 2013

Thank you for your attention!