In episode analysis we look in detail at a period
(episode) of high regional or subregional aerosol component concentrations
or high light extinction. The goal is to understand the emissions and
meteorology that result in the high extinction values. By considering
a substantial number of episodes covering each location, we can form
conceptual models of causes of haze.
We use whatever information
is available to help understand the episode. The analysis may include
Weather radar for precipitation and frontal locations
National Weather Service textual information
Anecdotal information from observers and news media
To help in the analysis we
created animated maps of IMPROVE and protocol measurements for the entire
network and coined the term “Hazagon” to indicate the relative amounts of
six major components of light extinction for that sample. We then choose episodes based on sites classified with 20%
worst light extinction.
During our analysis we note duration, frequency,
regional extent, season and components that contributed to the 20% worst light extinction.
Case studies completed by
COHA staff are located in the
We are working on a way to
query the episodes that we have investigated. The episode query page is not
operational but shows a potential product if it will be useful to users of
the COHA web site.