Trajectory Optimization for Balloon
Flight Forecasting
Considering the fact that trajectory methods are used
extensively in the planning and execution stages of long-range
balloon flights (Wetzel et al., 1995), it would be interesting
to evaluate if such a process can be automated to provide
a variety of pathways to take advantage of the balloon's
variable altitude capabilities. |
(c) 1995 Softkey International Inc.
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Research Results
Conceptually one would compute trajectories at several different
altitudes. Then after some period of travel, new trajectories
would be started at each of the trajectory positions, again at
several different altitudes. This process could be repeated as
frequently as computational resources permit. The final matrix
of trajectory positions with time and altitude could be used
to construct a pathway to a specific location within a specified
time interval. The method could be employed using archival data
to perform a complete evaluation to select optimal seasons or
starting locations. Or the computations can be performed operationally
using forecast meteorological fields to guide the balloon in
flight.
The example below illustrates the recent choice available to
the Solo-Challenger around the world flight team, which could
either take a northern or southern route. They decided to go
south.
The latest version of the HYSPLIT
trajectory optimization program is now available through
the READY website for registered HYSPLIT users. The example below
shows a recent forecast using the MRF meteorological forecast
data with three initial trajectories (5000, 8000, and 10000 MAGL)
originating in central New York. The isobaric trajectories show
very little horizontal shear during the first 48 hours when the
trajectories crossed the central Atlantic Ocean; ideal conditions
for long-range balloon travel. However, after the trajectories
split at 48 hours they show considerable horizontal and some
vertical shear as a results of a pair of deep low pressure systems
move through Europe and thus providing considerable uncertainty
for the balloon forecaster.
Further Information
HYSPLIT trajectory optimization
online.
NOAA press release for the
Steve Fossett successful around the world attempt.
NOAA press release for the
J. Renee solo around the world attempt by Kevin Uliassi.
HYSPLIT on-line publications.
References
Due to copyright restrictions, some articles are
not available directly on-line, but can be requested by Email.
You will be prompted, the article file name will appear in the
subject line, and no additional message is necessary.
Trajectory
Verification - Draxler, R.R. 1996, Trajectory Optimization
for Balloon Flight Planning, Weather and Forecasting, Vol 11,
March, pp. 111-114.
Wetzel, M., R. Borys, D. Lowenthal, and S. Brown, 1995: Meteorological
support to the Earthwinds Transglobal Balloon project, Bull.
Amer. Meteor. Soc., 76:477-487.
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