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Asia-Pacific Advanced Network. 27 August 2003. The Cloud Resolving Storm Simulator: Large-scale Parallel Computations. HPC application to Meteorology in Japan. TSUBOKI Kazuhisa SAKAKIBARA Atsushi. Hydrospheric Atmospheric Research Center, Nagoya University, Japan. OUTLINE.

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the cloud resolving storm simulator large scale parallel computations

Asia-Pacific Advanced Network

27 August 2003

The Cloud Resolving Storm Simulator:Large-scale Parallel Computations

HPC application to Meteorology in Japan

TSUBOKI Kazuhisa

SAKAKIBARA Atsushi

HydrosphericAtmospheric Research Center, Nagoya University, Japan

slide3

OUTLINE

  • Description of the numerical model: the Cloud Resolving Storm Simulator(CReSS)
  • Numrical Experiment of tornado within supercell
  • Numerical Experiment of typhoon
  • Numerical experiment of snow cloud over the sea
  • Summary
introduction
Introduction
  • Convective clouds and storms are highly complicated

systems of flows and hydro-meteors. Their structure

and dynamics are determined by a nonlinear interaction

between the fluid dynamics and the cloud microphysics.

  • In order to simulate an evolution of a convective cloud

storm, it is essential to formulate cloud physical

processes as well as the fluid dynamic and thermo-

dynamic processes.

slide5
A detailed formulation of cloud physics requires many

prognostic variables even in a bulk method such as

cloud, rain, ice, snow, hail and so on.

  • It is impossible to perform this type of simulation of

cloud systems without a huge memory and parallel

computing.

purposes
Purposes
  • A thunderstorm produces many types of severe weather: heavy rain, hail storm, downburst, tornado and so on.
  • The purposes of this study are to develop a cloud

resolving model, the Cloud Resolving Storm Simulator

“CReSS” and its parallel computing to simulate cloud-

scale to storm-scale phenomena.

  • The simulation of the thunderstorm will clarify the

characteristics of dynamics and evolution and

contribute to the storm-scale prediction.

targets of cress are
Targets of CReSS are ...

to perform large-scale numerical experiments of mesoscale storms and prediction experiments of real severe weather systems

  • within a very large domain, ~500 km × 500 km
  • with very high resolution, 1 km ~10 m in horizontal
  • with detailed cloud microphysics and
  • with optimization for high performance parallel

computers (including the Earth Simulator)

characteristics of cress
Characteristics of CReSS
  • CReSS is formulated in the non-hydrostatic and

compressible equation system.

  • Coordinate system is a terrain-following in atwo or

three dimensional geometry.

  • Prognostic variables are:
    • three-dimensional velocity components
    • perturbation of pressure
    • perturbation of potential temperature
    • subgrid-scale turbulent kinetic energy, TKE
    • mixing ratios for water vapor and several types of

hydrometeors

slide9
Finite difference method for the spatial discretization.
  • Time integration is mode splitting method.
    • Large time step: the leap-frog with the Asselin time filter.
    • Small time step : explicit both in horizontal and vertical or explicit in horizontal and implicit in vertical.
  • Advection is a fourth order scheme.
  • Turbulence is the first order closure and 1.5 order

closure with TKE.

  • Numerical smoothing is the second or forth order

computational mixing.

slide10
Cloud physics is formulated by a bulk method of cold

rain.

  • Prognostic variables for mixing ratios are:
    • water vapor
    • cloud water
    • rain water
    • cloud ice
    • snow
    • graupel
slide12
Initial conditions are:
    • horizontally uniform field from upper air sounding or

theoretical function

    • three-dimensionally inhomogeneous data
  • Lateral boundary conditions are:
    • rigid wall, periodic, zero normal gradient
    • wave-radiating
    • externally forced time-dependent condition
  • Ground model and surface processes have been

implemented.

  • Parallel processing is performed by the Message Passing

Interface, MPI.

overview of the tornado tatsumaki
Overview of the tornado (TATSUMAKI)

The tornado occurred on 24

September 1999 was one of the most

Intense tornadoes in Japan. It

occurred during day time. They

took many pictures and videos.

These are samples of the pictures

of the tornado. A dark funnel

reached to the ground from the

cloud. The horizontal diameter of

the tornado was about 500 m.

doppler radar observation of the tornado producing super cell
Doppler radar observation of the tornado-producing super-cell
  • Horizontal displays of radar echo of the

super-cell with a trace of the tornado

(tatsumaki) observed on 24 September 1999

in the Tokai District, Japan. The tornado

occurred at the central part of the a hook-

shaped echo.

  • Vertical cross-section of radar echo of the

super-cell. A vault structure is significant.

  • Horizontal display of Doppler velocity. A

signature of mesoscale cyclone was observed.

experimental design of simulation supercell and tornado
Experimental design of simulation- Supercell and Tornado
  • domain 48km × 48km × 12km
  • horizontal grid size 75m
  • vertical grid size 25 ~200m
  • grid numbers 603 × 603 × 63
  • integration time 4 hours
  • time increment large: 0.5s, small: 0.1s
  • microphysics the bulk cold rain type
  • initial condition Shionomisaki soundingdata at 09JST, 24 Sept.
  • initial disturbance warm bubble
  • boundary condition the wave-radiating type
  • platform SR8000, 8nodes
the 2 dimensional horizontal display of the simulated super cell
The 2-dimensional horizontal display ofthe simulated super-cell

CReSS successfully simulated the

super-cell observed in the Tokai

District. The simulated super-cell

was in quasi-steady state around

1.5 hours after the initial time.

The 2-dimensional horizontal display will show its evolution and

movement. The color level is the mixing ratio of precipitation, the

thick red lines are intense vorticity and white lines are vertical

velocity at a height of 1000 m. The thick blue lines indicate the

surface gust front. Arrows are the surface horizontal velocity.

close view of the simulated tornado in horizontal
Close view of the simulated tornado in horizontal
  • Vertical vorticity at a height of

100m (a) when the tornado was

generated and (b) in the mature

stage.

  • Pressure perturbation at a

height of 100m (a) when the

tornado was generated and (b)

in the mature stage.

The velocity field is in the cyclostrophic balance with

the pressure field.

close view of the simulated tornado in vertical
Close view of the simulated tornado in vertical
  • Vertical vorticity and pressure

perturbation.

  • Vertical vorticity and vertical

velocity.

the 3 dimensional movies of the tornado
The 3-dimensional movies of the tornado

Since the tornado within the super-

cell has a highly 3-dimensional

structure, we made the 3-dimensional

movies of the tornado obtained from

the simulation experiment.

The movies shows vertical vorticity

larger than 0.15 /s and the surface

temperature perturbation within the

box of 13 km in horizontal and

12 km in vertical. The period of

display is about 2 hours.

the 2 dimensional movie of vertical vorticity
The 2-dimensional movie of vertical vorticity

In order to examine a detailed process of the development of the

tornado, we will show a 2-dim. movies of vertical vorticity which

focus on the stage of the tornado genesis. The display is a

projection of the tornado on the west-east vertical plane.

The movies shows that the

tornado developed from the lower

level to the upper level.

experimental design of typhoon 0111
Experimental Design of - Typhoon 0111 -
  • domain 400km × 400km × 14km
  • horizontal grid size 4000m
  • vertical grid size 400m
  • grid numbers 103 × 103 × 35
  • integraion time 12 hours
  • time increment large: 3s, small: 1.5s
  • topographyincluded
  • surface processincluded
  • sea surface temp.contant at 300.16 K
  • micropysics the bulk cold rain type
  • initial condition JMA RSM analysis at 03Z Aug.05 2001
  • boundary condition JMA RSM analysis
  • platform VPP5000, 1node
the 3d animation of typhoon 0111
The 3D animation of Typhoon 0111

The simulation of Typhoon 0111 is

visualized in 3-dims. All calculation

domain is displayed. The color levels

show surface pressure perturbation.

The brightly white parts indicate

clouds and gray parts are rain.

The animation shows the typhoon which was located to the

west of the domain at the initial time moved into the domain

smoothly through the west boundary.

observation of snow clouds
Observation of Snow Clouds

Visible satellite image (GMS) at

15 JST

JMA radar at a height of 2 km

experimental design of snow cloud bands japan sea case on 5 january 2003
Experimental Design of Snow Cloud Bands- Japan Sea Case on 5 January 2003 -
  • domain 1080km × 720km × 10km
  • horizontal grid size 2000m
  • vertical grid size 300m
  • grid numbers 543 × 363 × 35
  • integraion time 18 hours
  • time increment large: 3s, small: 1s
  • topographyincluded
  • surface processincluded
  • sea surface temp.NCEP 1 week average
  • micropysics the bulk cold rain type
  • initial condition JMA RSM at 00Z Jan.05 2003
  • boundary condition JMA RSM
  • platform SR8000, 8node
result of the simulation
Result of the Simulation

Animation of horizontal display of

cloud mixing ratio (g/kg) and the

horizontal wind vectors at a height of

1350 m.

Animation of horizontal display of

precipitation mixing ratio (g/kg) and

horizontal wind vectors at a height of

450m.

slide29
Animation of horizontal display of

vorticity (10e-3/s) and the horizontal

wind vectors at a height of 1350 m.

Animation of horizontal display of

vertical velocity (m/s) and the

horizontal wind vectors at a height of

1350 m.

summary
Summary
  • We are developing the Cloud Resolving Storm

Simulator, CReSSfor simulations of cloud-scale to

storm-scale phenomena.

  • Parallel computing is essentially important for this

type of large simulations.

  • CReSS characteristic features and some result obtained

in dry experiments were presented.

  • The result suggested that CReSS is capable to simulate a

thunderstorm and a related phenomenon.

slide31
The result of the simulation experiment of the supercell

and the associated tornado was presented. CReSS

simulated both disturbances with a uniformly fine grid

spacing.

  • Prediction experiment of snow cloud over the sea showed that the

detailed structure of roll convections and mesoscale disturbances of snow clouds.

  • The result suggested that CReSS is capable to simulate a

thunderstorm and a related phenomenon.

future plans of cress
Future Plans of CReSS
  • Detailed cloud microphysical processes which resolve size distributions of hydrometeors
  • Parameterization of turbulence
  • Nesting in a coarse-grid model
  • Data assimilation of Doppler radar
  • Radiation of cloud
summary35
Summary
  • We are developing CReSSfor simulations of clouds and storms with parallel computation.
  • CReSS simulated the tornado within the supercell with the uniformly fine grid spacing (75m) in the large domain.
  • The simulation shows that successive formation of tornado vortex within the maximum updraft of the supercell.
  • The tornado develops from the surface and extends to the upper level.
  • We infer that the tornado is caused by stretching of the lower-level vortex resulted from shear instability.
experimental design of snow cloud bands labrador sea case on 8 february 1997
Experimental Design of Snow Cloud Bands- Labrador Sea Case on 8 February 1997 -
  • domain 250km × 120km × 12km
  • horizontal grid size 500m
  • vertical grid size 200m
  • grid numbers 503 × 243 × 63
  • integraion time 6 hours
  • time increment large: 2s, small: 0.5s
  • topographyincluded
  • surface processincluded
  • sea surface temp.constatnt at 3 C
  • micropysics the bulk cold rain type
  • initial condition NCEP analysis
  • boundary condition NCEP analysis
  • platform SX-6, 4node
the result of the simulation
The Result of the Simulation

Horizontal displays at height of 500m

  • vertical velocity
  • cloud mixing ratio (g/kg)
  • precipitation mixing ratio (g/kg)

Vertical cross-sections in zonal direction

  • vertical velocity
  • cloud mixing ratio (g/kg)
  • precipitation mixing ratio (g/kg)
  • zonal velocity (m/s)
  • pressure (hPa)
  • mixing ratio of water vapor (g/kg)
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