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MM5 Simulation of Hurricane Diana Genesis

In a key step toward improving the prediction of hurricanes, NCAR scientists have reproduced in a computer model the fine-scale structure that drives the birth and strengthening of tropical cyclones. The simulation marks the first time a cloud-resolving simulation has been able to reproduce the formation of a tropical cyclone, given only information about atmospheric conditions on a scale much larger than that of the cyclone.

To resolve the eyewall and precipitation bands within a tropical cyclone, the MM5 model was used. With a horizontal distance as small as 1.2 km between the model's computation points, MM5 is one of the world's highest-resolution models for reproducing storm-scale weather across a large area. Diana was chosen because of ample surface data and because a well-defined nontropical low preceded its formation.

 

Variables Visualized  
CLW:
Cloudwater mixing ratio in g/kg
RNW:
Rainwater mixing ratio in g/kg
U, V, W:
Wind vectors in m/s
Model  
Model Type:
Atmospheric
Model:
MM5
Data  
Data Size:
100 GB
Horizontal Resolution:
1.2 km x 1.2 km
Time Evolution:
2 days (00 UTC 8 September to 00 UTC 10 September 1984)
Timesteps:
49
Supercomputer:
IBM SP 9076 "Blackforest", NCAR. 552 CPUs employed  (138 4-processor Winterhawk nodes. A Compaq 4100 cluster (8 nodes) was employed for MM5 preprocessing and two 8-processor SGI Origin 2000 systems were used for data post-processing.
CPU Time:
34 hours
Visualization  
Atmosphere Layer:
Troposphere
Horizontal Resolution:
499 x 499 m
Vertical Resolution:
37 levels
Software:
Vis5D
Hardware:
Onyx with Infitinite Reality Graphics
CPU Time:
6 hours
Research Project
Subject:
Severe Weather
Scientists:
Dr. Jordan Powers, NCAR/MMM
Dr. Chris Davis, NCAR/MMM
Visualization:
Don Middleton, NCAR/SCD
Other Collaborators:
George Fuentes, NCAR/SCD
Al Bourgeois, NCAR/MMM
John Michalakes, NCAR/MMM
Date Catalogued:
2002-08-05
Rights:
© 2002, UCAR, All rights reserved.


 

Rainwater at .65g/kg is shown as a yellow isosurface and Cloudwater at .35g/kg is shown in white. Because of the course time resolution, the structures jump around a lot, but the clear definition of the eye just off the coast is visible at the end of the time sequence which is 49 hours long.