COSTA An Introduction Nils van Velzen email: [email protected]

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Data Assimilation Summer School, Sibiu, 6 th August 2009 Common Set of Tools for Assimilation of Data COSTA COSTA An Introduction Nils van Velzen email: [email protected] www.costapse.org

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www.costapse.org. COSTA An Introduction Nils van Velzen email: [email protected]. www.costapse.org. Outline. Data assimilation and calibration Existing software and programming issues COSTA Application of COSTA with WAQUA/TRIWAQ Conclusions. Data assimilation and calibration. - PowerPoint PPT Presentation

Transcript of COSTA An Introduction Nils van Velzen email: [email protected]

Page 1: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

COSTA

An Introduction

Nils van Velzen email: [email protected]

www.costapse.org

Page 2: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Outline

• Data assimilation and calibration• Existing software and programming issues• COSTA• Application of COSTA with

WAQUA/TRIWAQ• Conclusions

www.costapse.org

Page 3: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Data assimilation and calibration

• (Dynamic) simulation models– Weather forecast– Air quality– Shallow water (storm surge)– Ocean modelling– Reservoir

• Predictions are not perfect!

Page 4: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Data assimilation and calibration

• Measurements:– Satellites– Buoy– Radar– Weather stations

Page 5: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Data assimilation and calibration

– Make model perform better using the available observations:

• Calibration: change model parameters in order to reduce the difference between the model predictions and observations

• Data assimilation: combine the model forecast and observations into a mixed forecast

Page 6: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Existing software and programming issues

• Simulation software is complex• More complex is combined with Data

assimilation and/or Calibration methods• Expensive to develop and maintain• Splitting up software is in general a

good idea– Less complex– Possible to reuse (parts of) the code

Page 7: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Existing software and programming issues

• Why people think they have to develop a custom implementation of a DA method:– Computational efficient– Need to handle model specific issues

• Are these assumptions correct? Issues are:– Which method to implement?– Expensive– Incompatible– Potentially full of bugs

Page 8: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

COSTA• A problem solving environment for data

assimilation and calibration– Components and their interface– Data assimilation methods– Platform for exchanging models and methods

• Free software (LGPL)

Page 9: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Steps to prepare model codes for implementing data assimilation

• Identify the state-vector of your model and those parameters and forcing (you think) you want to use

• Isolate the model time step--This is 90% of the work and has to be done

for a custom data assimilation implementation as well

--COSTA provides tools to simplify this work

Page 10: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

COSTA• A generic environment where user can

easily try out different DA-methods to their models

• A generic environment where method developers can easily implement their method to different models

Page 11: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

COSTA• Most data assimilation actually only requires

information about model state and observation at the same time.

• This makes it possible to implement model, observation and data assimilation methods separately as independent components.

Page 12: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

COSTA componentsModel, observations and DA-method

Page 13: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Model Component

• Model component in COSTA (formal)

• State of a model instance• Methods to get or change the state of

model instance

, , ,d t

M t t tdt

x

x p u w

, , , , tx u p w

Page 14: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Model Component• Propagate the model state-vector

• Get, set, axpy for

• GetObsValues:

, , ,t t

t

t M t t t dt

x x p u w

y t H t x

, , ,t t tx p u w

Page 15: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Using COSTA

Page 16: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Using COSTA

• Use the “costawb” program to combine a model with a DA-method without any programming

• Model components are dynamic libraries and are linked to the “costawb” program

Page 17: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

WAQUA/TRIWAQ

• Simulation model for shallow water• Used operational by the Dutch

Rijkswaterstaat• Long history of data assimilation

– Too expensive– Inflexible

Page 18: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

WAQUA/TRIWAQ

• Domain decomposition and parallel computing

• COSTAmodel component

• RRSQRTFilter

Page 19: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

The WAQUA/TRIWAQ model Deterministic model:

Stochastic model:

or

φ ti+ 1=A [ φ t i ,u t i ,g ]

φt t i+1 pu t i+ 1p A t i+ 1 = A [ φ t t i ,u f t i +W u pu t i ,g ]+W A p A t i

diag α A p A t i diag α u pu t i 0

η u t i η A t i

x t t i+1 =M i [ x t i ]+η t i

Page 20: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Page 21: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Page 22: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Deterministic and Stochastic We want a separation between

deterministic and stochastic model Use deterministic model for other applications Play with alternative

noise models

Page 23: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Deterministic and Stochastic WAQUA/TRIWAQ uses ADI-scheme:

One time step consist of two half time steps Time correlation applied each half time step

New approach: Time correlation

each whole time step

Different results!

Page 24: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Challenge Can we:

Separate filter and method Method?

have same results? Similar performance?

Is the COSTA modelinterface sufficientfor this task?

Page 25: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Page 26: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Conclusions

• COSTA offers a flexible framework for using and developing data assimilation methods.

• Successful coupling with “real” models:– WAQUA/TRIWAQ– Lotos-Euros– Chimere

Page 27: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Conclusions

• Easy to use• Complete basic functionality available:

– Implementation available for all basic building blocks

– Growing number of available methods• Support for parallel computing

Page 28: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Thank you!

Page 29: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Existing software and programming issues

Page 30: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Tools for creating COSTA models

• Simple model builder– Handles the “object oriented” aspects of the model– You only need to implement 4 functions

• Model combiner– Combine multiple COSTA models in one composite

model– Create a stochastic model from a deterministic model

• Black Box model builder– Create a COSTA component for a model without

changing the model code

• Support for parallel models

Page 31: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Automatic parallelization

Page 32: COSTA An Introduction  Nils van Velzen  email: c.vanvelzen@tudelft.nl

Data Assimilation Summer School, Sibiu, 6th August 2009

Common Set of Tools for Assimilation of DataCOSTA

Using parallel models