Institute of Marine Sciences, National Research Council (ISMAR-CNR), Venice

Transcription

1 Overview of the esurge-venice project Marco Bajo Institute of Marine Sciences, National Research Council (ISMAR-CNR), Venice Istituto di Scienze Marine (ISMAR-CNR), National Research Council of Italy, Venice, Italy (Georg Umgiesser, Marco Bajo) Istituto di Scienze dell'atmosfera e del Clima (ISAC-CNR), National Research Council of Italy, Padova, Italy (Stefano Zecchetto, Francesco De Biasio, Antonio della Valle) Istituto di Biofisica (IBF-CNR), National Research Council of Italy, Pisa, Italy (Stefano Vignudelli) I Istituzione Centro Previsioni e Segnalazioni Maree (ICPSM) of the Venice Municipality, Venice, Italy (Alvise Papa) esurge, Delft, January

2 esurge-venice project: main objectives from SoW The esurge-venice project was focussed on four aspects: 1) Selection and data mining of a number of Storm Surge Events occurred in the Venice lagoon during the period 1999-present day 2)Making relevant EO and other data related to the Storm Surge Events available to the user community (including satellite wind, altimetry, in-situ data and model forecasts) 3)Providing a demonstration NRT service (esurge-venice live) of EO data products and services in support of operational and experimental forecasting and warning services 4)Running a number of re-analysis cases, both for historical and contemporary storm surge events, to demonstrate the usefulness of EO data within the Venetian storm surge community esurge, Delft, January

3 Selection and data mining of a number of Storm Surge Events occurred in the Venice lagoon during the period 1999-present day The selection is based exclusively on in-situ data, water level time series at the Acqua Alta CNR platform (AAPTF). The criteria of selection are the following: 1) The SEV occurs when the total water level is 110 cm and the surge component 40 cm 2) temporal window of a SEV is 72 hours before the event and 120 hours after the SEV occurrence: 72 hours before is the estimated time to produce the sea level rise, while 120 hours after have been taken to follow the seiches produced by the SEV events. 3 esurge-venice Final Presentation, ESRIN 9 December 2014 esurge, Delft, January 2015

4 Selection and data mining of a number of Storm Surge Events occurred in the Venice lagoon during the period 1999-present day Selection criterion: SSL=Total level height - astronomical component Total level height > 110 cm AND SSL > 40 cm esurge, Delft, January

5 Making relevant EO and other data related to the Storm Surge Events available to the user community (including satellite wind, altimetry, in-situ data and model forecasts) EO Ocean Wind Vector over the Adriatic Sea Altimeter TWLE SST Sampling time: SST 1 per day; scatterometer/altimeter variable In-situ total water level atmospheric pressure wind speed and direction. Sampling time: 10 minutes. NWP derived model related quantities Sea surface stress Inverse Barometer effect IB Sampling time: analysis: every 6 hours; Forecast: 3 hours SSM quantities Astronomical tide time series at AAPTF SSL and the barotropic transports in all the nodes of the computational grid over the Mediterranean Sea SSL and the barotropic transports interpolated into a regular grid of 0.05 degree over the Adriatic Sea Sampling time: 1 hour esurge, Delft, January

6 Making relevant EO and other data related to the Storm Surge Events available to the user community (including satellite wind, altimetry, in-situ data and model forecasts) All the NetCDF files, written in the NetCDF Climate and Forecast (CF) Metadata Convention v. 1.4, are available through the esurge SEARS and stored in the OpenDAP server at ISMAR Satellite wind, SST and NWP quantities esv_sevyyyymmdd_aaabbbbb_yyyymmddthhmmss+nnn.nc yyyymmdd: is the SEV date; AAA: three characters referring to the source of the data [QKS ASC OSC]: QuikSCAT ASCAT OCEANSAT satellite winds; [GCM]: model wind stress and drag coefficient; [MDS GHR]: satellite-derived sea surface temperature. BBBBB: 5 characters depending on AAA : AAA = [QKS ASC OSC], BBBBB is the orbit number; AAA = [GCM LAM], BBBBB is the declared model grid spacing (in km); AAA = [MDS GHR], BBBBB is set to SST00. yyyymmddthhmmss: is the base date+time for the data contained in the file NNN: number of hours lapsed to obtain valid data in the file are valid used (only for forecast, 000 otherwise) Altimeter data esv_sev date _ mission orbit _ date T time +000.nc Mission is the name of the satellite (TOP for TOPEX/Poseidon; JA1 for Jason 1; JA2 for Jason-2 and ENV for Envisat); Date is in the form yyyymmdd Orbit is the number of the satellite ground track in four digits; Time is in the form hhmmss Reading software esurge, Delft, January

7 Providing a demonstration NRT service (esurge-venice live) of EO data products and services in support of operational and experimental forecasting and warning services The NRT system started in December 2013 The constraints triggering the NRT processes are: sea surface level >= 110 cm OR SSL >= 40 cm This choice was to guarantee at least some NRT SEVs, given the short time to the end of the project. For the non-nrt (historical) SEVs they were: sea surface level >= 110 cm AND SSL >= 40 cm esurge, Delft, January

8 Providing a demonstration NRT service (esurge-venice live) of EO data products and services in support of operational and experimental forecasting and warning services Time window for new SEVs: 3 days before and 5 days after the forecast day of SEV occurrence (nine days in total) esurge, Delft, January

9 Providing a demonstration NRT service (esurge-venice live) of EO data products and services in support of operational and experimental forecasting and warning services Esurge Venice data for old and new SEVs are available at the esurge web-page: And in Near Real Time at the web-page: esurge, Delft, January 2015

10 Running a number of re-analysis cases (3 to 5), both for historical and contemporary SEVs, to demonstrate the usefulness of EO data within the Venetian storm surge community Twenty two SEVs have been selected for re-analysis, according to the availability of the EO data esurge-venice Final Presentation, ESRIN 9 December 2014 esurge, Delft, January 2015

11 Running a number of re-analysis cases, both for historical and contemporary SEVs, to demonstrate the usefulness of EO data within the Venetian storm surge community Summary Figure reports the modulus of the skew Obs-model SSL ordered by crescent values. With respect to the reference (REF) line, the scatterometer mitigated ECMWF winds bring the main improvement, while the assimilation of altimeter TWLE* still needs a refinement. In principle the two methods are perfectly compatible, since the altimeter assimilation should decrease the error of the initial state of the dynamical system, while the wind tuning decreases the error on the forcing. The first is often necessary, due to the wind underestimation, which is higher during extreme storm events. The second can be particularly important in case of seiches, triggered by previous storm surge events. TWLE* = TWLE-astronomical tide 11 esurge-venice Final Presentation, ESRIN 9 December 2014 esurge, Delft, January 2015

12 User's feedback and recommendations User's feedback The main user of the esv project is ICPSM, that considers very important the results obtained but preliminary for an operational use. The results coming from application of scatterometer data seem already established and in line with the past activities using scatterometer data for the subjective analysis of sea level forecast, and then possibly usable in an operative context; those related to altimetry, despite the results indicating good potentialities, need further analysis, development and the involvement of all the countries bordering the Adriatic Sea. The ICPSM activity is at present significantly affected by difficulties related to the administration of the city of Venice, but the hope is to move forward to a transition phase in which methods and techniques developed by the project can be turned into operation for daily forecast. Other potential user can be ISPRA Venezia or other Countries bordering the Adriatic Sea (e.g., Slovenia). 12 esurge-venice Final Presentation, ESRIN 9 December 2014 esurge, Delft, January 2015

13 Scientific roadmap Scientific roadmap as esv follow-up a) to keep the NRT service operational b) to find statistically more robust calculation of the scatterometer correction factor to model wind c) to test the wind tuning method with forecast wind d) to make a better pre-processing of altimeter data e) to find a common reference between tide gauge and altimeter data (bias correction) f) to specify better variances and covariances of errors for the altimeter data g) to increase the number of data that can be potentially assimilated (extension to the Mediterranean Sea, try the tide gauge-altimeter merging method) 13 esurge-venice Final Presentation, ESRIN 9 December 2014 esurge, Delft, January 2015

14 Thank you for your attention! esurge, Delft, January 2015