Prediction and estimation of effects on coastal oceanof climate variation ----- abnormal sea level, Kyucho

High-resolution coastal ocean modelnested in a basin-scale ocean model

Prediction of maritime disaster ----- oil spill

Nesting Ocean Model for parallel vector processors

Miyazawa, Y. (IGCR/FRSGC) et al.

Contents

1. Nesting Model for Kuroshio simulation

2. The Earth Simulator

3. Modification of the model code for the Earth Simulator

High-resolutionmodel

1/12 deg.(10km)

Low-resolutionmodel

1/4 deg.(30km)

Nesting POM

driven by the NCAR daily data

Nesting grid

3x3 grids

Bilinearinterpolation

One-waynesting

Eddy kinetic energy

(initialized by DA of T/P in 1993.01) Observation (1993.03-1993.04)

Prediction of Kuroshio path

Simulation

1/48 deg.(2.5km) grid

Part of the Kuroshio intrudes the Tokyo Bay

Nesting of another coastal model (by a TIT group)

Earth Simulator

Developed by JAERI/JAMSTEC/NASDA

8 vector processors(8x8Gflops) share main memory(16GB) 1node

640 nodes are connected by a single-stage crossbar network

Earth Simulator

Earth Simulator

Speed up of the POM code

• Vectorization: 99.7 %• Parallelization by MPI (SPMD)• domain decomposition method ----- latitudinal direction• initialization for MPI and subroutines for communication are inserted in the POM

Efficiency of the code

Numberof PE

4MPI 4

8MPI8

8SMP8

16MPI 8SMP2

Speedup

3.87 7.30 6.47 12.4

Efficiency 98.9% 98.6% 96.7% 98.1%

Low-resolution model: 543x282x21

On NEC/SX-5

Efficiency of the code

Numberof PE

4MPI 4

8MPI8

8SMP8

16MPI 8SMP2

Speedup

3.95 7.65 6.80 14.4

Efficiency 99.6% 99.4% 97.4% 99.2%

High-resolution model: 758x530x35

On NEC/SX-5

Nesting by MPI

Low-resolution model

mkbnd

send_nestbuf

Network

High-resolution model

set_openbnd

recv_nestbuf

MPI MPI

Problems

• More tests for the nesting ocean model

• Asynchronous coding of MPI

• Development of higher-resolution ocean models for Earth Simulator

Another POM codes for Earth Simulator ES-OGCM (by T. Kagimoto)

• Global Model

• Atmosphere/Ice/Ocean Couple Model

• Fortran 90/95

• Parallelization by MPI: asyncronous communication