Patterns of Convective Influence and Temperatures in the Tropical Tropopause Layer during the Airborne Tropical TRopopause EXperiment (ATTREX)

Abstract:

The Tropical Tropopause Layer, a zonal torus of air around 13-18km altitude and -30 to 30 latitude,
is the gatekeeper for air entering the stratosphere from the troposphere. The overall speed of the upward motion affects the input of all the trace constituents, but how the upward transfer is distributed
between convective injection and slow ascent indirectly driven by breaking waves
has a critical effect on both water and some short-lived species (e.g., bromine compounds). Convection's
potential ability to bypass the cold trap in the center of the TTL torus can contribute to stratospheric
hydration. Convection can also quickly move short-lived tracers to higher altitudes (and higher ozone
values), and contribute to ozone destruction.

This presentation focusses on the relationship of convectively influenced air to temperature in the TTL, with
an emphasis on the qualitative evolution during ATTREX. We use a technique of obtaining global, high
resolution distributions of convective cloud tops at 3-hourly intervals to derive distributions of
convectively influenced air in the TTL, and examine its relationship to TTL temperature. TTL temperature
distributions are often affected directly by convection, but equatorial and other gravity waves having a variety
of space and time scales are also important. The relationship of these temperature patterns to output
from convection will determine whether hydrated air remains in the TTL, or whether it is stripped of its
water soon after injection.