IBM demonstrates Deep Thunder
at the 1999 American Meteorological Society conference
The capabilities developed and utilized for a number of past experiments
were demonstrated and refined at the annual meeting of the American
Meteorological Society (AMS: January 10-15, 1998 in Dallas, TX).
Deep Thunder was replicated in the IBM booth as part of the conference's
technical exhibition. The system was adapted to the Dallas area as shown
below. For this and any of the subsequent images, you can view a
higher-resolution version by simply clicking on it. You can also
interact with this map via a scene in PanoramIX
or simplified VRML.
New 24-hour mesoscale forecasts were produced at 8 km resolution in
a region roughly 800x800 km in extent several times each day during the
conference. The computation took place on six 120 MHz P2SC thin nodes
on an SP that was in the booth. One 135 MHz P2SC wide node was used
for I/O. Three workstations (two IBM RS/6000 43P-260s and one IBM
Intellistation M-Pro) and two laptops (IBM RS/6000 860 and IBM Thinkpad
760E) were available in the booth to interact with the model and analyze
results. Due to a number of logistical difficulties, raw observations
and access to data assimilation via LAPS for the pre-processor step were
unavailable at the hotel where the AMS conference took place. Therefore,
RAMS was initialized with the results from the ETA synoptic scale model
from NCEP, which are computed
at 32 km resolution, but sampled at 80 km for public availability.
These same data were also used for boundary conditions for the model.
Output from RAMS every 10 minutes of forecast time were provided for
browsing visualization. Animations were produced routinely as the primary
mechanism to evaluate the model. The system also permitted simple
tracking of the simulation, so that the interactive tools could be utilized
while the model was running. If there were problems in the model run, then
the execution could be terminated and the model restarted with new input
observations. In addition, interactive visualization applications
for the analysis of post-processed model results
were available operationally, which are illustrated below.
The following image is from one of the animations
produced during the conference. The image shows a terrain map, overlaid
with color-filled contour bands of wind chill temperature for 9 AM on January
13. Coastline, state, county and river maps are draped over the topography
with the location of several cities marked by name and the wind chill temperature.
Predicted clouds are visualized as a white, translucent isosurface of cloud
water density. Surface winds are shown as streamlines with directional
arrows colored by speed. The 73-frame animation
shows a cold-front passing through central Texas. (The animation
can also be viewed at higher resolution, but the file is three times bigger.)
The location of the front as it moves in time can be seen where the wind
streamlines appear to be "bunched" together with narrower contours of wind
chill behind it. In the animation, the motion of clouds follows the
front. This particular time step can also be examined via a flyover
animation, simplified VRML geometry and
a PanoramIX scene. (The flyover
animation can also be viewed at higher resolution, but the file is
about two times bigger.)
Other visualizations of this same forecast are available
for viewing.
After each RAMS execution, all of the results
are collected and reorganized into a form that can be used by standard
meteorological analysis tools as provided by NWS (e.g., AWIPS), FSL and
others. These post-processed data were made available for two interactive
applications. This includes all of computed variables from the model,
but at hourly resolution unlike the browser application that worked with
a subset of variables but at six times the temporal resolution. Here
is a sample image and animation created
with this application for the previously discussed forecast run initiated
on January 13 at 0Z UTC (6 PM CST on January 12).
A surface variable (pressure) has been selected for display as pseudo-colored
filled contour bands, which are overlaid on a topographic map. Any
of the surface variables produced by the model may be presented in this
fashion. Coastlines (black), state boundaries (white) and rivers
(blue) are draped on the surface. An upper air variable (relative
humidity) has been selected for display via surface extraction. The
surface at 75% is requested in translucent tan, which corresponds roughly
to a cloud boundary. Another field (temperature) has been selected
to show as a vertical slice, which is pseudo-color contoured. Any
of the three-dimensional fields available from the model can be visualized
with either of these methods. The upper air wind data can be seen
along two vertical profiles, which are specified interactively, and via
streamribbons. The direction of the model wind field along these
"virtual sounding" is shown via vector arrows. Both the arrows and
ribbons are pseudo-colored by horizontal wind speed. The length of
the arrows also corresponds to the horizontal speed. Points along
the profile are used as seeds for the streamribbon integration. Each
profile is realized as a pseudo-colored tube, which is contoured by the
variable selected for isosurface realization (i.e., relative humidity).
The visualization for the profile toward the center of the domain can help
illustrate the three dimensional effects of the front moving through the
area as shown earlier.
The other application is a RAMS slicer, which provides two- and 2-1/2-dimensional
interaction with surface and upper layers of the model data. This
capability was introduced for the first time operationally
at the AMS 99 conference. Additional details about the application
is available in a paper that discusses the
visualization portion of Deep Thunder. Here is a sample image and
animation for the same forecast produced
by the slicer.
Five different surface variables have been selected in a combined visualization.
Mean sea level pressure is shown as pseudo-color. Wind velocity is
illustrated as streamlines with directional arrows arrows, colored by speed.
Colored line contours of relative humidity in increments of 10% are shown.
These planar representations are deformed vertically by lifted index to
create a shaded surface. A coastline map (black) and state boundaries
(white) are draped on the surface. Finally, temperature values at
discrete locations are also shown by value on the surface. Any of
the surface and upper air fields available from the model can be visualized
with any of these methods. Since lifted index can be used to indicate
the relative instability in the atmosphere, the peak in its surface illustrates
where the front is located. This representation is a very effective
method, especially in animation, of
showing the motion of a front.
Other visualizations of this same forecast are available
for viewing.
To evaluate these model results, it is useful to compare
them to actual observations as well as
other model results.
A paper that summarizes the visualization
work for this project and the results is available for you to read.
It was presented at the American Meteorological
Society (AMS) Conference, January 10-15, 1999 in Dallas, TX.
Alternatively, you can download a PDF copy
of this paper, L. Treinish, Creating Effective Visualizations for Operational
Weather Forecasting.
lloydt@watson.ibm.com
