Distances and statistics of local molecular clouds in the first Galactic
  quadrant
  We present an analysis of local molecular clouds (-6 <VLSR< 30 km/s, i.e.,
<1.5 kpc) in the first Galactic quadrant (25.8{\deg} <l<49.7{\deg} and
|b|<5{\deg}), a pilot region of the Milky Way Imaging Scroll Painting (MWISP)
CO survey. Using the SCIMES algorithm to divide large molecular clouds into
moderate-sized ones, we determined distances to 28 molecular clouds with the
background-eliminated extinction-parallax (BEEP) method using the Gaia DR2
parallax measurements aided by AG and AV, and the distance ranges from 250 pc
to about 1.5 kpc. These incomplete distance samples indicate a linear
relationship between the distance and the radial velocity (VLSR) with a scatter
of 0.16 kpc, and kinematic distances may be systematically larger for local
molecular clouds. In order to investigate fundamental properties of molecular
clouds, such as the total sample number, the linewidth, the brightness
temperature, the physical area, and the mass, we decompose the spectral cube
using the DBSCAN algorithm. Post selection criteria are imposed on DBSCAN
clusters to remove the noise contamination, and we found that the separation of
molecular cloud individuals is reliable based on a definition of independent
consecutive structures in l-b-V space. The completeness of the local molecular
cloud flux collected by the MWISP CO survey is about 80%. The physical area, A,
shows a power-law distribution, dN/dA \propto A^{-2.20+/-0.18}, while the
molecular cloud mass also follows a power-law distribution but slightly
flatter, dN/dM \propto M^{-1.96+/-0.11}.
