GTP
and
TNT
Boulder, January 26, 2009
1

• GTP has been in existence almost since the beginning of NCAR
(Deardorff, Gilman, Herring, Leith, Lilly, Lorenz, McWilliams, Orszag, Patterson, Thompson, …)
History: see Herring, in IUTAM Symposium, Kerr & Kimura Eds, Kluwer (2000 )
• 40+ members across all divisions and labs at NCAR + a few external universities
(CU, Dartmouth, LANL, Nagoya, Penn State, UCLA, Warwick)
• GTP, @ $50k, is ~ 10% of the GTP+TNT combined budgets
Imperative: cross-cutting research with outreach
• Support research on turbulent flows in a variety of contexts , with focused topics drawing on GTP seed funds
• Short-term (3day) visitors, with a ``monthly’’ seminar program
• Long-term visitors , for one week [to one year, very rarely possible]
• Workshops [and schools, 2 in 20 years]
• For the last two years: small partial support for graduate students
URGENCY: TO INVOLVE THE YOUNGER GENERATION 2

Peter Sullivan (ESSL/MMM - GTP):
Boundary layers
``The atmospheric and oceanic boundary layers may be the most crucial ingredients in hurricane dynamics despite their small vertical extent’’ (K. Emanuel, 2004)
SST
.
. .
.
.
High wind atmospheric PBL 25m/s
Cold water hurricane wake generated by ocean turbulence and surface wave effects
.
.
Storm track
Large eddy simulations and modeling of turbulent flows and of boundary layers in complex geophysical flows, with multi-scale dynamics and physical processes.
Transition wave - turbulence
3
Breaking waves, spray, bubbles, turbulence?

Joe Tribbia (ESSL-CGD & GTP), with Jim McWilliams (UCLA-GTP)
Pathway to dissipation in the atmosphere and ocean
Thermal / mechanical driving on planetary scale
Thin instabilities (baroclinic, frontal) drive inertial cascades to non-rotational scales
Further instabilities (K-H, convective) needed to get to 3D isotropic turbulence and dissipation, and transport processes
No complete GFD simulation to date. It must span a 2D range from 10 6 m to 10-100m
(3D Turbulence), waves and anisotropy (rotation and/or stratification and/or magnetic fields and/or bottom topography …)
4

• The Geophysical Turbulence Program at NCAR investigates nonlinear multi-scale eddy-wave interactions for a wide range of geophysical and astrophysical flows. It also develops, analyzes and validates analytical and phenomenological models, numerical methods and experiments as tools for UCAR and for the university community, here and abroad.
• Retreat
+ meeting of GTP to be organized in 2009
(Joe Tribbia)
• To be followed by a meeting of a small advisory board (as per the request of the NCAR review panel many years ago …)
5

J. Baerenzung (NCAR): Spectral modeling of utrbulent fluids
G. Boffetta (LANL): Two-dimensional turbulence.
C. Bustamante (U. Warwick): Singularities of the Euler equations.
P. Hamlington (U. Mich.:, Reynolds stress anisotropy and vorticity alignment.
S. Heinz (U. Wyoming): Unified stochastic and deterministic turbulence models (07).
J. Liu (CSU): Characteristic methods for fluid transport problems .
D. Stanescu (U. Wyoming): Discontinuous Galerkin methods (07).
A. Tuck (NOAA): A molecular view of vorticity and turbulence.
V. Uritsky (U. Calgary): Self-organized criticality.
…
… MHD (WC Müller, W-H Matthaeus, …)
6

M-E Brachet, ENS-Paris: codes with symmetries in MHD , RK4 and Euler flow with helicity.
J.F. Cossette ( grad. student , U. Montreal, with Piotr Smolarkiewicz): Semi-Lagrangian schemes.
M. Damron ( grad. student , U. Arizona, with Larry Winter): a non-Markovian model of rill erosion.
J. Finnigan (Commonwealth Scient.): Canopy turbulence in roughness sub-layers
D. Jarecka ( grad. student , U. Warsaw, with Wojciech Grabowski): Impact of entrainment and mixing on cloud dynamics and microphysics.
H. Jonker, U. Delft: A refined view of vertical transport by cumulus convection.
P. Ortiz, U. Granada: Coupled dynamics of boundary layers & evolutionary landforms like dunes.
Z. Piotrowski, U. Warsaw: Numerical realizability of thermal convection.
L-P Wang, U. Delaware: Turbulent collision-coalescence of cloud droplets and impact on warm rain initiation.
7

Wang, Franklin, Ayama & Grabowski - ESSL/MMM-GTP
• PDF of angle of approach of colliding droplets: dominance of inward relative motion due to turbulence
• Solid line: model with turbulence black dots: Direct Numerical
Simulation (DNS)
8

08 Theme of year: 3-wks Summer School & 3 wkshps (K. Julien @CU, CISL-EOL-ESSL-RAL)
* Theory and modeling of Geophysical Turbulence: LANL (B. Wingate) + Wisconsin (L. Smith)
* Petascale computing for Geophysical Turbulence: CORA (J. Werne) + UCLA (B. Stevens)
* Observations and sensors: RAL (L. Cornman) + EOL (S. Oncley) + ESSL (R. Lenschow)
(J. Fernando [AZ] in charge of the Observation week of the summer school)
No magnetic field in TOY08 …
2009?: Turbulent mixing in the upper ocean & boundary layers (W. Large, ESSL-CGD)
2010: Rotating stratified flows (V. Zeitlin, Paris et al.)
Past workshops:
• Turbulence and Dynamos at Petaspeed ( 2007)
• Turbulence and Scalar Transport in Roughness Sub-layers (2006)
• Modeling MHD turbulence with applications to planetary and stellar dynamos (2006)
• Theme of the Year (TOY-06) on Multi-scale modeling (one workshop sponsored)
• Coherent Structures in the Atmosphere and Ocean (2005)
• Atmospheric Turbulence and Mesoscale Meteorology (2005)
•
Cumulus Parameterization in the Context of Turbulence Studies (2004)
9

• G. Branstator (ESSL-CGD) & J. Berner (now in MMM): distinct signatures of nonlinearity in climate dynamics
• W. Grabowski (ESSL-MMM): Parameterization of small-scale and micro-scale processes in models resolving larger scales
• J. Herring (ESSL-MMM): Stratified turbulence
• R. Lenschow (ESSL-MMM): Analysis of C-HATS experiment
(Horizontal Array Turbulence Studies, + Oceans, Canopies, Anisotropy)
• C-H Moeng (ESSL-MMM) with J. McWilliams (UCLA), R. Rotunno
(MMM), P. Sullivan (MMM) & J. Weil (CIRES/CU) : Evaluation of twodimensional Planetary Boundary Layer ( PBL ) models using Large Eddy
Simulations (LES)
10

Peter Sullivan, ESSL-MMM -& GTP :
Passive versus active scalar in the dry
PBL using LES in a large domain 1000 2 X128 or 50 2 km X 6km
(comparable to a field campaign)
Passive scalar is at large scales Dynamically active scalar is at

• M. Rast (CU): Convection + ionisation in the solar convection zone
• P. Sullivan (ESSL-MMM) et al.: wind-wave interactions ;
• J. Tribbia (ESSL-CGD): Multi-scale and climate
New!
• J. Berner (ESSL-MMM) et al .: stochastic parametrization for numerical weather prediction (NWP) with flow-dependent formulation of unresolved processes
12

Stochastic parameterization of spectral backscatter for
NWP and climate model-error
 Stream function perturbations with a prescribed kinetic energy spectrum:
J. Berner, A. Fournier, S-Y. Ha, J. Hacker & C. Snyder
 Successfully applied to probabilistic NWP
(ECMWF pseudo-spectral model) by Shutts
(2005), and Berner et al. (2009).
 Ongoing: Implementation into WRF limited-area ensemble model using 2D planar Fourier analysis.
 Preliminary Result: the Brier score of u is improved (shown is score for events 0 < u <

( p ) , where

( p ) is climatological standard deviation at
13 pressure p ), but more samples are needed.

Commonality of issues in fundamental multi-scale dynamics for the Earth’s atmosphere and ocean, and for solar and solarterrestrial physics
• Request for a quadrupling of the funds (50k 200k):
– Create a GTP Post-doctoral fellow
– Create a GTP Graduate student position
– Create a sabbatical GTP visitor
The over-arching goal is to investigate and model turbulent

Commonality of issues in fundamental multiscale dynamics for the Earth’s atmosphere and ocean, and for solar and solar-terrestrial physics
• Request for a quadrupling of the funds (50k 200k):
– Create a GTP Post-doctoral fellow
– Create a GTP Graduate student position
– Create a sabbatical GTP visitor
Decision making process: annual meeting of GTP members
(+)
The over-arching goal is to investigate and model turbulent flows in weather, climate, solar physics and space weather
15


And now, the Turbulence Numerics Team
16

Aimé Fournier
Project Sc.
@1 FTE
Pablo Mininni
Scientist 1 @ 0.25
AP @ 0.6
Duane Rosenberg,
Software Eng. III,
@ 1 FTE
QuickTime™ and a
decompressor are needed to see t his picture.
Julien Baerenzung,
Post-doc, 1 FTE
(until June 2009)
Ed Lee, GRA, 0.5 FTE
(until January 22, 2009)

yesterday
Core of 2.85 FTE

75% at Buenos Aires 40% deputy director of ESSL
Aimé Fournier
Project Sc.
@1 FTE
Pablo Mininni
Scientist 1 @ 0.25
AP @ 0.6
Duane Rosenberg,
Software Eng. III,
@ 1 FTE
QuickTime™ and a
decompressor are needed to see t his picture.
Julien Baerenzung,
Post-doc
(until June 2009)
Ed Lee, GRA, 0.5 FTE
(until January 22, 2009)

yesterday
Core of 2.85 FTE

No GRA and no post-doc
Two NSF gants submitted in 2008
19

•
Investigate the basic properties of multi-scale flows
•
Exploit their commonality multi-scale interactions, nonlinear phenomena, geophysical turbulence, eddies and waves
* Analyze data and implement a variety of turbulence models
•
Seed the applications for the Earth and beyond: atmosphere, ocean, PBL, solar physics and space weather
•
To that effect, develop, test and make available a suite of tools and data sets @ petascale and beyond
(computing, and also accessing, visualizing, analyzing & sharing the data)
20

•
Investigate the basic properties of multi-scale flows
At the highest possible Reynolds number(s)
•
Exploit their commonality multi-scale interactions, nonlinear phenomena, geophysical turbulence, eddies and waves
* Analyze data and implement a variety of turbulence models
•
Seed the applications for the Earth and beyond: atmosphere, ocean, PBL, solar physics and space weather
•
To that effect, develop, test and make available a suite of tools and data sets @ petascale and beyond
(computing, and also accessing, visualizing, analyzing & sharing the data)
21

3
thanks to BTS and ASD allocations
I. 2006: Magnetohydrodynamics
(MHD), without rotation
• First evidence of a dual direct energy cascade: isotropic k -3/2 at large scale, anisotropic k

-2 weak turbulence at small scale in the highest-ever Reynolds MHD run
• First numerical evidence of rolling up of vorticity & current sheets

Pablo Mininni et al.
R

~ 1700 GHOST
22

• First evidence of lack of universality in decaying MHD without a uniform magnetic field (2048 3 equiv. grid):
Taylor-Green flow, 3 runs, 3 different energy spectra
Collision of two current sheets
(viz.: VAPOR, CISL)
Ed Lee et al.
Phys. Rev. E 2008/12 kaleidoscope
23
MAYTAG

• First evidence of lack of universality in decaying MHD without a uniform magnetic field (2048 3 equiv. grid):
Taylor-Green flow, 3 runs, 3 different energy spectra
Ed Lee et al., in preparation
Collision of two current sheets
(viz.: VAPOR, CISL)
Ed Lee et al.
kaleidoscope
24
MAYTAG

Developing , testing, or using models for fluid & MHD turbulence:
* Chollet-Lesieur model
* Lagrangian averaged model (D. Holm, …)
* Spectral model based on EDQNM (two-point turbulence closure)
^ with eddy viscosity incorporating helical terms
^ with eddy noise incorporating phase information
^ for any energy spectrum
(Julien Baerenzung et al.)
Applications to Navier-Stokes (including rotation) and MHD
25

II. 2008: Rotation with helical forcing, without magnetic field
R

~ 1100 , Ro = 0.05 GHOST
• First evidence of a non-intermittent and non-Kolmogorovian direct energy cascade at low Rossby number , governed by the direct cascade of helicity (h+e=4), together with an inverse cascade of energy
• First evidence of the persistence of strong cyclonic events in rotating turbulence in the presence of helicity , together with strongly turbulent columnar structures

Pablo Mininni et al.

Vorticity magnitude (zoom), above a threshold
26

II. In 2009:
* Analysis and modeling of the large run with rotation and helical forcing
R

~ 1100 , Ro = 0.05
• Parametric study using the model TBD
Thanks to a special
CISL 5 mo. post-doc allocation for JB

Closer look of vorticity magnitude, above a threshold: cohabitation
27


Model: Eddy viscosity and eddy noise with variable index energy spectrum

Tests on non-helical flows down to Rossby numbers of 0.02
Fig.: Build-up of anisotropy over time
Julien Baerenzung et al., in preparation
QuickTime™ and a
decompressor are needed to see this picture.
Taylor-Green flow
GHOST + X
28

2D-Navier-Stokes
Aimé Fournier et al., 2008
• Decay for long times
(incompressible)
• Formation of dipolar vortex structures
• Gain in the number of degrees of freedom (~ 4) with
AMR, compared to an equivalent pseudo-spectral code (periodic boundary conditions)
GASPAR 29


The need for accuracy in adaptive mesh refinement, when looking at max. norms (Fig.: current in 2D-MHD reconnection)
Duane Rosenberg et al (2007)
Also: Development of optimized Schwarz preconditioning, in collaboration with Amik
St Cyr
New: Implementation of a conservative energy scheme (AF +DR)
30
GASPAR

• GASpAR : High-order adaptive Mesh Refinement code for turbulent flow, and a PDE framework for adaptive mesh solutions
* Future : Boussinesq equations, 3D-MHD, Planetary Boundary Layer
• GHOST : Primary production pseudo-spectral code for turbulent flows
Modular numerics and physics : 2D/ 3D; compressibility; (Hall)-MHD; rotation
* Plans : * Stratification, and implementation of (several) LES
* Upgrade for petascale and beyond (today: up to ~ 4000 proc.)
^^^^^^^^^^
• Other code: MAYTAG: MA gnetoh Y drodynamics TA ylorG reen code with enforced symmetries leading to a gain of 32 in CPU / storage
Code developed in F’08 by M-E Brachet (ENS Paris)
31

(runs performed at NCAR, NERSC and Pittsburgh)
• Navier-Stokes: ^ Taylor-Green (TG) flows, 2048 3 grids
^ ABC flows, 2048 3 grids
• Navier-Stokes with rotation: ABC, decay,1536 3 grid
• MHD: ^ 1024 3 forced dynamo runs;
^ 1536 3 grid, decaying flow;
^ 2048 3 equivalent grids with imposed TG symmetries
Taylor Reynolds numbers of 1100 or above 32

1Basic research in rotating turbulent flows (in progress):
Numerical simulations, phenomenological approach, and spectral modeling (with helicity and with eddy noise)
2 - Stratified turbulent flows (GHOST)
(with/without rotation, boundaries, passive tracer; & numerical adaptivity)
Potential targeted applications to the stable planetary boundary layer
(with Peter Sullivan, ESSL; & Rod Frechlich, RAL) and to aircraft safety (with Larry Cornman, RAL)
3 - Bottom topography using non-uniform mesh (GASPAR)
33

1- Basic research in rotating turbulent flows (in progress): Numerical simulations, phenomenological approach, and spectral modeling
2 - Stratified turbulent flows (with/without rotation, boundaries, passive tracer; and numerical adaptivity). Potential targeted applications to the stable planetary boundary layer and to aircraft safety (with ESSl and RAL)
3 - Bottom topography, using mesh adaptivity
A- Tools for the community (GASPAR, GHOST), going to petascale and beyond
B- High-Reynolds number data sets for the community, and how to handle these data sets
• A- Sustain the TNT team at its present level
• B- Recruit in TNT a Scientist 1 or Scientist 2 in weather/climate turbulence and its modeling
C- Obtain substantial computer resources including in the team
34

TNT collaborations at NCAR, past and present:
Tom Bogdan (now at NOAA), Paul Charbonneau (now at Montreal), John Clyne (CISL),
Larry Cornman (RAL), Rod Frehlich (RAL and CU), Jack Herring ( emeritus , ESSL-M 3 ),
Han-Li Liu (ESSL-HAO), Alan Norton (CISL), Amik St Cyr (IMAGE-CISL),
Peter Sullivan (ESSL-MMM), Joe Tribbia (ESSLCGD), …
TNT collaborations outside NCAR, past and present:
A. Alexakis (Paris), F. Baer (U. Md), A. Bhattacharjee (UNH), M-E Brachet (Paris),
B. Breech (U Del.), M. Bustamante (Dublin), V. Carbone (Calabria),
C. Cartes (Santiago), S. Cowley (UCLA), P. Dmitruk (Buenos Aires),
P. Fisher (Argonne), S. Galtier (Orsay), K. Germaschewski (UNH), J. Graham (Lindau),
D. Holm (Imperial, LANL), G. Krstulovic (Paris), D. Lathrop (U. Md), W-H Matthaeus
(Bartol), D. Montgomery (Dartmouth), C-S Ng (Alaska), J-F Pinton (Lyon), H. Politano
(Nice), Y. Ponty (Nice), J. Toomre (CU), M. Rast (CU), R. Reddy (PSC), J. Riley (U.
Washington), M. Taylor (Sandia), L. Turner (Cornell), V. Uristsky (Calgary), H.
Wang (U. Md), …
35

Publications with reviewers, 2007-2009
[1]
•
Alexakis, A., P. D. Mininni, A. Pouquet, 2007: Turbulent cascades, transfer, and scale interactions in magnetohydrodynamics. New J. Phys.
, 9 , 298, doi: 10.1088/1367-2630/9/8/298 .
• Baerenzung, J., H. Politano, Y. Ponty, A. G. Pouquet, 2008: Spectral modeling of turbulent flows and the role of helicity.
Phys. Rev. E , 77 , 046303, doi: 10.1103/PhysRevE.77.0463033
• J. Baerenzung, H. Politano, Y. Ponty and A. Pouquet,, `Spectral Modeling of Magnetohydrodynamic Turbulent Flows,'’
Phys. Rev. E 78, 026310 (2008).
• Carbone, V., A. G. Pouquet, 2008: An introduction to fluid and MHD turbulence for astrophysical flows: Theory, observational and numerical data and modeling. Invited set of Lectures EEC School on Astrophysical Plasmas , L Vlahos and P Cargill, Ed., Springer-Verlag, 69-131
• Carlos Cartes, Miguel D. Bustamante, Annick Pouquet, Marc E. Brachet,Generalized Eulerian-Lagrangian description of
Navier-Stokes and resistive MHD dynamics,'' Fluid Dyn. Res, 41, 011404 (2009).
• Clyne, J., P. Mininni, A. Norton, M. Rast, 2007: Interactive desktop analysis of high resolution simulations: Applications to turbulent plume dynamics and current sheet formation. New J. Phys.
, 9 , 301, doi: 10.1088/1367-2630/9/8/301 .
• Cowley, S., J.-F. Pinton, A. Pouquet, 2007: Focus on magnetohydrodynamics and the dynamo problem. New J. Phys.
, 9 ,
E04, doi: 10.1088/1367-2630/9/8/E04
•
A. Fournier, D. Rosenberg and A. Pouquet, ``Dynamically adaptive spectral-element simulations of 2D incompressible
NavierStokes vortex decays,'' to appear, GAFD, Special issue `` Vortex dynamics from quantum to geophysical scales,'’
Guest Editors: C. Barenghi, D. Dritschel and A. Gilbert (2008).
• Graham Pietarila, J., D. D. Holm, P. Mininni, A. G. Pouquet, 2008: Three regularization models of the Navier-Stokes
• equations. Phys. Fluids , 20 , 035107, doi: 10.1063/1.2880275
.
•
Graham Pietarila, J., D. Holm, P. Mininni, A. G. Pouquet, 2008: Highly turbulent solutions of the Lagrangian-averaged
Navier-Stokes alpha model and their large-eddy-simulation potential. Phys. Rev. E , 75 , 056310, doi:
10.1103/PhysRevE.76.056310
.
J. Pietarila Graham, P.D. Mininni, and A. Pouquet, The Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottleneck, Phys. Rev. E, to appear (2009).
• E. Lee, M.E. Brachet, A. Pouquet, P.D. Mininni and D. Rosenberg,``A paradigmatic flow for small-scale magnetohydrodynamics,'’ Phys. Rev. E 78, 066401 (2008).
• Matthaeus, W. H., A. G. Pouquet, P. Mininni, P. Dmitruk, B. Breech, 2008: Rapid directional alignment of velocity and magnetic field in magnetohydrodynamic turbulence. Physical Review Letters , 100 , 085003, doi:
10.1103/PhysRevLett.100.085003
.
36

[2]
* P.D. Mininni, A. Alexakis and A. Pouquet, Scale interactions and scaling laws in rotating flows at moderate Rossby numbers and large Reynolds numbers,'' Phys. Fluids 21, 015108 (2009).
• P.D. Mininni and A. Pouquet, ``Helicity cascades in rotating turbulence,'' to appear, Phys. Fluids (2009), arxiv:0809.0869.
•
Mininni, P., A. Alexakis, A. G. Pouquet, 2008: Non-local interactions in hydrodynamic turbulence at high Reynolds numbers: The slow emergence of scaling laws. Phys. Rev. E , 77 , 036306, doi: 10.1103/PhysRevE.77.036306
.
• Mininni, P., A. G. Pouquet, 2008: Energy spectra stemming from interactions of Alfven waves and turbulent eddies.
Physical Review Letters , 99 , 254502, doi: 10.1103/PhysRevLett.99.254502
.
• Mininni, P. D., D. C. Montgomery, L. Turner, 2007: Hydrodynamic and magnetohydrodynamic computations inside a rotating sphere. New J. Phys.
, 9 , 303, doi: 10.1088/1367-2630/9/8/303
• .Mininni, P. D., 2007: Inverse cascades and alpha effect at a low magnetic Prandtl number. Phys. Rev. E , 76 , 026316, doi:
10.1103/PhysRevE.76.026316
.
1
•
Mininni, P., A.. Alexakis, A. Pouquet, 2007: Energy transfer in Hall-MHD turbulence, cascades, backscatter and dynamo action. J. Plasma Phys.
, 73 , 377-401, doi: 10.1017/S0022377806004624 .
1
•
Mininni, P., A. Alexakis, A. G. Pouquet, 2008: Scale interactions in hydrodynamic turbulence at large Reynold numbers.
IUTAM Book Series: IUTAM Symp. Comput. Phys. And New Perspectives in Turb.
, Kaneda, Y, Eds., Springer-Verlag, 4,
125-130, doi: 978 1-4020-6471-5 .
• P.D. Mininni, E. Lee, A. Norton, and J. Clyne, Flow visualization and field line advection in computational fluid dynamics: application to magnetic fields and turbulent flows, New J. Phys. 10(12), 125007/1-23 (2008).
•
P. Mininni, P. Sullivan and A. Pouquet,``Two examples from geophysical and astrophysical turbulence on modeling disparate scale interactions,'’ Summer school on mathematics in geophysics, Roger Temam and Joe Tribbia Eds.,
Springer Verlag, to appear (2009).
• C. S. Ng, D. Rosenberg, K. Germaschewski, A. Pouquet and A. Bhattacharjee,``A comparison of spectral element and finite difference simulations with adaptive mesh refinement for the MHD island coalescence instability problem,'’ to appear,
Astrophys. J. Suppl. (2009).
• Yannick Ponty, Pablo D. Mininni, Jean-Philipe Laval, Alexandros Alexakis, Julien Baerenzung,Francois Daviaud,
Berengere Dubrulle, Jean-Fran cois Pinton, Helene Politano and Annick Pouquet, ``Linear and non linear features of the
TaylorGreen Dynamos,'’ Comptes Rendus de l'Academie des Sciences (Paris), 9, 749 (2008).
•
Ponty, Y., P. D. Mininni, J.-F. Pinton, H. Politano, A. Pouquet, 2007: Dynamo action at low magnetic Prandtl numbers:
Mean flow versus fully turbulent motions. New J. Phys.
, 9 , 296, doi: 10.1088/1367-2630/9/8/296 .
3
•
Pouquet, A. G., A. Alexakis, P. Mininni, D. Montgomery, 2008: Dynamics of the small scales in magnetohydrodynamic turbulence. IUTAM Book Series: IUTAM Symp. Comput. Phys. And New Perspectives in Turb.
, Kaneda, Y, Eds., Springer-
Verlag, 4, 305-312, doi: 978 1-4020-6471-5 .
•
Rosenberg, D., A. Pouquet, P. D. Mininni, 2007: Adaptive mesh refinement with spectral accuracy for MHD in two space dimensions. New J. Phys.
, 9 , 304, doi: 10.1088/1367-2630/9/8/304 37
•
Wang, H., J. J. Tribbia, F. Baer, A. Fournier, M. A. Taylor, 2007: A spectral element version of CAM2. Mon. Wea. Rev.
, 135 ,
3825-3840.

38

39

As an example: Summary of the GTP workshop on
Turbulence & Scalar Transport in Roughness Sub-layers (RSLs)
Jielun Sun et al., ESSL-MMM
• Types of roughness elements considered include:
– Vegetated canopies
– Urban and suburban environments
– Underwater plant communities
– Ocean waves
– Wind farms
• Although there are similarities, profound differences in turbulence structures are found among these RSLs depending on rigidity and porosity of roughness elements
– Over-ocean RSLs are strongly affected by speed and direction of swell and can impact the entire PBL.
– Imprint of urban geometry greatly impacts turbulence structures in
RSL due to building shapes and distributions.
– Underwater RSLs due to aquatic vegetation can fill entire channel depth.

Past, present & future experiments : e.g., HATS, OHATS, CHATS, AHATS
(Horizontal Array Turbulence Studies, + Oceans, Canopies, Anisotropy)
40