The Environmental Working Group (EWG) of the Joint Planning and Development
Office (JPDO) is charged with modeling future NAS enhancements. Modeling must
consider a number of scenarios under which NAS enhancements will operate. One
important scenario is severe en route weather in the CONUS. Because of the complexity
of the simulation modeling and limited resources, only a few scenario days will be
selected to represent the impact on the NAS of severe weather. A challenge is how to
select the days for modeling. On one hand, one could argue that severe weather patterns
and movements are quite different each day, making each day unique—this makes
selection arbitrary and trivial.
However, there may be sufficient similarity of severe weather on certain days, and that
grouping of days is feasible. If groupings are feasible, then selection of sample days
could be more informed.
I was asked by the EWG to repeat an analysis I'd published regarding severe weather
from 1999 and 2000—apply cluster analysis to severe weather data, and produce groups
of days of 2004. These groupings, based purely on weather data, would then be further
analyzed, by Metron Aviation, with respect to NAS "responses", i.e., the characterization
of TFM actions, plus flight delays, cancellations, etc. The resultant days would be
selected to span the sample space (a year of severe weather in the CONUS) and become
the scenario days for the simulation modeling. Results from simulation modeling could
be annualized with the knowledge of how the selected days compared to the rest of the
year. Other conditions, such as mostly good weather, or CONUS airport weather are
considered separately from the analysis here.
This paper describes efforts in applying cluster analysis to 2004 data to find severe
weather day groupings.
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