  The CO(1-0) line has been carefully calibrated as a tracer of molecular gas
mass. However, recent studies often favor higher J transitions of the CO
molecule which are brighter and accessible for redshift ranges where CO(1-0) is
not. These lines are not perfect analogues for CO(1-0), owing to their more
stringent excitation conditions, and must be calibrated for use as molecular
gas tracers. Here we introduce the Arizona Molecular ISM Survey with the SMT
(AMISS), a multi-CO line survey of z~0 galaxies conducted to calibrate the
CO(2-1) and CO(3-2) lines. The final survey includes CO(2-1) spectra of 176
galaxies and CO(3-2) spectra for a subset of 45. We supplement these with
archival CO(1-0) spectra from xCOLD GASS for all sources and additional CO(1-0)
observations with the Kitt Peak 12m Telescope. Targets were selected to be
representative of the galaxy population in the stellar mass range of $10^9$ to
$10^{11.5}$ M$_\odot$. Our project emphasized careful characterization of
statistical and systematic uncertainties to enable studies of trends in CO line
ratios. We show that optical and CO disk sizes are on average equal, for both
the CO(1-0) and CO(2-1) line. We measure the distribution of CO line luminosity
ratios, finding medians (16th-84th percentile) of 0.71 (0.51-0.96) for the
CO(2-1)-to-CO(1-0) ratio, 0.39 (0.24-0.53) for the CO(3-2)-to-CO(1-0) ratio,
and 0.53 (0.41-0.74) for the CO(3-2)-to-CO(2-1) ratio. A companion paper
presents our study of CO(2-1)'s applicability as a molecular gas mass tracer
and search for trends in the CO(2-1)-to-CO(1-0) ratio. Our catalog of CO line
luminosities will be publicly available with the published version of this
article.
