  The James Webb Space Telescope (JWST) is nearing its launch date of 2018, and
will undoubtedly revolutionize our knowledge of exoplanet atmospheres. While
several studies have explored what the limits of the telescope will be in terms
of exoplanet characterization, less has been done to specifically identify
which observing modes will be most useful for characterizing a diverse range of
exoplanetary atmospheres. We use an information content based approach commonly
used in the studies of Solar System atmospheres. We develop a system based upon
these information content methods to trace the instrumental and atmospheric
model phase space in order to identify which observing modes are best suited
for particular classes of planets, focusing on transmission spectra.
Specifically, the atmospheric parameter space we cover is T=600-1800 K,
C/O=0.55-1, [M/H]=1-100$\times$Solar for a R=1.39 R$_J$, M=0.59 M$_J$ planet
orbiting WASP-62-like star. We find that obtaining broader wavelength coverage
over multiple modes is preferred over higher precision in a single mode given
the same amount of observing time. Regardless of the planet temperature and
composition, the best modes for constraining terminator temperatures, C/O
ratios, and metalicity are NIRISS SOSS+NIRSpec G395. If the target's host star
is dim enough such that the NIRSpec prism can be used, then it cam be used
instead of NIRISS SOSS+NIRSpec G395. Lastly, observations that use more than
two modes, should be carefully analyzed because sometimes the addition of a
third mode results in no gain of information. In these cases, higher precision
in the original two modes is favorable.
