> July 25, 2000

ACTS Workshop Committee

Lawrence Berkeley National Laboratory

National Energy Research Scientific Computing Center

One Cyclotron Rd

Berkeley, CA 94720

Re: ACTS Workshop Application

Dear Committee Members:

I am writing to you to apply for the position to participate in the ACTS
Workshop. Currently, I am a postdoctoral fellow at Marine Modeling and
Analysis Program, Costal Survey Development Lab at NOAA. The project I
am working on includes developing a real-time version of CH3D (a 3D
Curvilinear Hydrodynamics Model) to generate nowcasts and forecasts of
surface salinity and temperature fields in order to predict the
distribution of noxious biota in the Chesapeake Bay in real time.

CH3D is a finite difference model with boundary-fitted curvilinear grids
in the horizontal and Cartesian coordinate in the vertical. The current
version of the model has 2129 horizontal cells and a maximum of 20
vertical layers, resulting in a total of 10,657 computational cells. The
horizontal resolution ranges from 1 km in tributaries to 5 km in
continental shelf. The vertical layer is 1.52m. After compiling the code
using the *O4* optimization level on a Dec-Alpha 500 MHz work station, a
one year simulation with a time step of 5 minutes takes about 9 hours to
finish. However, given that Chesapeake Bay has many steep channels, a
higher resolution grid is needed to resolve the bathymetry in order to
reduce errors in the salinity and temperature forecasts. For example, if
the horizontal cells are to be reduced by half, the time step has to be
reduced by half in order to satisfy CFL criteria; the overall
computation time is likely to increase to 5 times that of the current
grid, if the I/O time required by Dec-Alpha is also added. This implies
that one year simulation on a Dec-Alpha 500 MHz workstation will take
about 45 hours. To accurately map the bathymetry of the Chesapeake Bay,
the resolution needs to be much finer than the example given here, which
will make running CH3D in real-time impossible on the Dec-Alpha
workstation. Hence, the future task for me is to parallelize the CH3D
code and run the code on an 8cpu SGI Origin in our lab or run the code
on a Beawolf Clusters (an ongoing project in our lab).

Besides the need to make CH3D run more efficiently in a high performing
computing environment, I am also interested in what types of software
that ACTS toolkits offer to analyze and visualize large volume of data.
Currently, I am using Matlab to handle the data manipulation and
visualization. Matlab is very efficient in data analysis, but for
graphic generation, Matlab is not flexible enough especially in a batch
mode. I hope that ACTS toolkits will provide a better solution.

Meanwhile, it is worth mentioning that I went to a Parallel Computing
Workshop earlier this year at University of Kentucky. I have obtained
basic knowledge about parallel computing and had hands-on experience
using Message Passing Interface, Domain Decomposition Algorithms, Krylov
solvers, Preconditioners, Parallel Software Libraries (PETSc), Grid
Partitioning Techniques and Profiling. Through the interaction with
other participants of the workshop, I have learned that parallel
computing has wide applications in many scientific fields.

I am very interested in this unique opportunity to learn the ACTS
toolkits for parallel computing and to use these tools in my research in
the future. Enclosed please find my short CV with a list of publication.
Your favorite consideration is highly appreciated. I am looking forward
to hearing from you.

Sincerely,

Zhen (Jean) Li

Ph. D.

NOAA/NOS/CS/CSDL/MMAP

1315 East-West Hwy

Silver Spring, MD 20910