A comparison of two paradigms: The relative global roles of moist convective versus nonconvective transport

Here MOZART-2 is driven by input meteorological fields from the National Center for Environmental Prediction/ National Center for Atmospheric Chemistry (NCEP/NCAR) reanalysis data set during 2001 - 2002 filtered at approximately 2.8 degrees latitude by 2.8 degrees longitude. Idealized tracers are used to identify deep moist convectively processed airmasses in MOZART-2, where the convection is parameterized using the Zhang and McFarlane scheme.

The simulations show that the troposphere can be divided into a convectively processed regime where deep moist convective transport is predominantly responsible for the transport of trace species from the boundary layer and a nonconvectively processed regime. The boundary between the convectively processed and nonconvectively processed regimes lies between approximately 300 and 310 K. The interplay between moist convective and nonconvective transport explains many aspects of the global tropospheric distribution of trace species, including seasonal, latitudinal and longitudinal changes in species distribution.