Tropical Internal Variability and its Reflection on the Global Climate System
Kyle Swanson [kswanson@uwm.edu], Atmospheric Sciences Program, University of
Wisconsin-Milwaukee
Variability internal to the climate system presents a significant challenge to the detailed
attribution of climate change, as well as to usefulness of cyclic variability, most notably the
solar cycle, as a means to study the climate response. Here, we will focus on how variability
in the tropical climate system, primarily due to changes in the character of the El
Niño/Southern Oscillation, impacts the global climate system. Emphasis will be on: (i)
bounding the magnitude of internal variability and its reflection in radiative/precipitation
subsystems, using both satellite and surface observations; (ii) extending those results to the
climate shift of the 1970’s, as well as more recent climate shifts; and (iii) the character of
apparent recent wild variability in the tropical hydrologic cycle and its ramifications for nearterm global climate variability.