Example LAPS visualization
As part of the effort in developing forecasts during the Olympics, the
results from the LAPS pre-processing, assimilation step are analyzed as
well as RAMS output. Tools similar to those for RAMS were not developed
for study of LAPS results during the Olympics. But since this step is critical
to the application of RAMS as well as other mesoscale models, the approach
used for RAMS visualizations is now being applied to LAPS. An example of
this is illustrated at the bottom of this page, which shows assimilated
data for the same time period as shown with the RAMS data below.
This image showing RAMS data is a full-resolution workstation screen
capture of a Data Explorer-based application that was used by the forecasters
at NWS to examine RAMS output for the Olympics. It shows surface humidity
as pseudo-colored topography. Surface winds are visualized as vector arrows
indicating direction, which are warped onto the local terrain and pseudo-colored
by speed. A cloud boundary is represented by a translucent white isosurface
of total cloud water density (both liquid and ice) at 10-4 kg/kg.
Inside the cloud isosurface is a translucent cyan isosurface of RAMS-derived
reflectivity (at 30 dBz). The reflectivity corresponds to internal rain
shafts. Several options for selecting data and how they are presented are
available via various control panels, some of which are visible in the
figure. In addition, there are some ancilliary controls (going from left
to right in the image), for creating output (animations produced interactively
or in the background, creating image snapshots, or saving the geometry
rendered in an image for subsequent processing), the selection of which
model run to study (enumerated by the date and start time of the run),
a VCR-like widget for specifying time steps of interest, and optional annotation.
Click on the image to see a full-size image of the same data. There is
an MPEG animation related to these data.
Now consider the LAPS image. Looking toward the northwest, there is
an isosurface of specific humidity at 0.001 kg/kg, which is pseudo-colored
by temperature. A depression corresponding to the coastal region is visible.
The terrain is also colored by a heat index scale, which is derived from
temperature and humidity data. Three virtual wind profilers can be seen.
Click on the image to see a full-size image of the same data. There is
an MPEG animation for this example.
These profiles are derived from the ability of a user to interactively
probe the atmospheric volume from LAPS with the mouse as a virtual met-station.
That same probe can be used to define a virtual sounding, a graphical analogue
to a meteorologist placing a collection of instruments at a specific location
to observe the real atmosphere. In this case, one can derive the same information
from the simulated or analyzed atmosphere (i.e., measurements of specific
physical quantities at locations of interest). Such a probe can then be
extruded into a profile tube. In this case, each extruded profile is pseudo-colored
by specific humidity. Vector arrows and streamribbons of wind velocity
from each profiler are also visible, which are pseudo-colored by wind speed.
The streamribbons are twisted according to a derived wind vorticity. The
terrain is overlaid with state (white), and river (blue) and coastline
(black) maps. A 70-frame MPEG animation will illustrate
these techniques and data over time.
You can see additional images
and learn more about this project, and the visualization work being done.
You can learn more the regional weather model and the parallelized
implementation on an IBM SP.
lloydt@watson.ibm.com
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