Microscale Modelling Workshop. 27^th March 2003, room 401B, UK Met Office , Bracknell, 10:30 for 11:00 start. Lunch ~ 12:30-13:15, and 16:00 finish.

Programme.

For more detailed discussions see the background web page on http://www.env.leeds.ac.uk/~alan/microscale/workshop1a.html

Workshop Outline:

The (outline) objectives of the microscale model project are:
1. To carry out a thorough review of current capability to model atmospheric flows and processes down to the building scale, including the modelling of building-scale flows themselves.
2. To adapt or build from scratch a core dry dynamics and thermodynamics code capable of addressing the research objectives of UWERN within the orographic flow and boundary layer areas (including urban flows). This will inevitably involve addressing the problem of very steep orography (i.e. cliffs).
3. In due course, to add to (2) physical and chemical models for a wide range of processes.
4. Provide support to UWERN for the modelling system.
5. Run workshops on the development and usage of the system.

The first workshop will be principally concerned with the first two objectives. The outcomes of the workshop should be:
1. A plan for which models, which test problems and which contributors will be involved in the review.
2. A plan for who will contribute, and on what timescale, to answering the following three questions:
a. Which equation set(s) should be used.
b. What type of grid system should be used (e.g. terrain following, boundary fitted, terrain intersecting...)
c. What solution method should be adopted (e.g. finite volume, etc)

The focus initially will be on the science of the problem, and what areas the model will be aimed at addressing. The analysis of test problems could be a guide for the development.

Draft Programme: 1^st Microscale Modelling workshop: A review

Each talk should include 5 minutes for comments and questions at the end.
10:30 Meeting room (Coffee)
11:00 Introduction: Stephen Mobbs: Background to the project
11:15 Alan Gadian: " Structure of the workshop. What we are trying to achieve? "
11:20 Andy White: "Equation sets"
11:35 Nigel Wood: " Validity of anelastic and other equation sets as inferred from normal-mode analysis"
11:50 Andy Brown: " Blasius and orography issues "
12:00 Tito Toro: "High order non-oscillatory schemes for advection-reaction equations"
12:10 Ian Roulstone: "Data Assimilation"
Short discussion to highlight outstanding issues. To be continued over ...

12:30 to 13:15 Sandwich lunch

13:15 Rex Britter & Bill Dawes: " Microscale Modelling from an Engineering perspective"
13:35 Mike Cullen: " Issues about a fine scale model " (presented by Alan Gadian)
13:50 Christiane Montavon & Alan Burns: " Experience of modelling atmospheric flows with a commercial CFD package"

14:10 Further questions on presentations and final questions relevant to individual talks.

With specific attention to the General Comments and Specific Issues raised below, the following issues need addressing.
What are the specific and achievable goals?
What strategy should we employ, and what is a good strategy?
How are we to achieve the objectives?

15:20 Summary and outcomes?.
15:30 Tea
16:00 Close

Specific Issues that need addressing:

Grids and grid structures.

Equation sets e.g. compressible, anelastic etc… LES capability? Discretisation of equations.

Vertical co-ordinate systems and representation of orography

Horizontal co-ordinate systems, e.g. variable, 2 way nested grids.

Compatibility with other models and Data Assimilation issues

Pressure solvers, numerical advection and time stepping schemes

Turbulence closure and 1+ order schemes

Structure of the initial tests.

General Comments:

Engineering codes with unstructured grids are the ways forward. Why not develop a "relevant equation set"? What about microphysics and moisture?

Why not develop a currently existing compressible model, e.g the M.O. Unified Model New Dynamics for small scales?

Why not develop one of the good anelastic models currently available?

We want something designed that is easy to run and can be used on a variety of platforms. A research rather than a forecasting tool is required.

How "steep" is steep terrain? Should we even be aiming at street canyon type flow?

With only limited resources, what "new" can be achieved?

How can we maximise current UK knowledge and experience to make informed decisions about the advantages and disadvantages of current schemes?

Should we conduct any inter-comparisons /experiments on current models to test limitations, and if so what?

Attendees:

Stephen Belcher , Alan Burns , Rex Britter , Andy Brown , Xiaoming Cai , Ken Carslaw ? , Ian Castro ? , Peter Clark , Terry Davies , Bill Dawes , Alan Gadian , Sue Gray , Brian Golding , Martin Juckes , Roy Kershaw , Paul Mason , Christiane Montavon , Stephen Mobbs , Martin Miller , Ian Roulstone , Chris Smith , Piotr Smolarkiewicz , Andrew Staniforth , Glenn Shutts ? , John Thuburn , Tito Toro , Simon Vosper , Neils Wedi , Andy White , Nigel Wood.

Unable to attend:

Mike Cullen , Doug Parker , Ian Renfrew.

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Further details email Alan Gadian