Time and Space Scale Interactions in the Climates System: Implications
for Climate Variability and Predictability
Gerald A. Meehl, Matthew Wheeler
National Center for Atmospheric Research, Boulder, Colorado
Poger Lukas
University of Hawaii, U.S.A.
George N. Kiladis
NOAA Aeronomy Lab, U.S.A.
Klaus M. Weickmann
NOAA climate Diagnostics Center, U.S.A.
Adrian J. Matthews
University of East Anglia, Norwich, U.K.
Interactions involving various time and space scales, both within the tropics
and between the tropics and midlatitudes, are ubiquitous in the climate system.
The concept of longer time scales and larger space scales setting the base state
for processes on shorter time scales and smaller space scales is explored.
Decadal time scale base states of the coupled climate system set the context for
the manifestation of interannual time scales (El Nio/Southern Oscillation,
ENSO and tropospheric biennial oscillation, TBO) which are influenced by and
interact with the annual cycle and seasonal time scales. Those base states in
turn influence the large-scale coupled processes involved with intraseasonal and
submonthly time scales, tied to tropical-tropical and tropical-midlatitude
teleconnections. All of these set the base state for processes on the synoptic
and mesoscale and regional/local space scales. Events at those relatively short
time scales and small space scales may then affect the longer time scale and
larger space scale processes in turn, reaching back out to submonthly,
intraseasonal, seasonal, annual, TBO, ENSO and decadal. Global coupled models
can capture some elements of the decadal, ENSO, TBO, annual and seasonal time
scales with the associated global space scales. However, coupled models are less
successful at simulating phenomena at subseasonal and shorter time scales with
hemispheric and smaller space scales. Due to the synergistic interactions of the
time and space scales, a high priority must be placed on improved simulations of
all of the time and space scales in the climate system (particularly the
subseasonal time scales and hemispheric and smaller space scales which are not
well simulated at present) if we hope to successfully forecast phenomena beyond
the synoptic scales.
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Hongjun Zhang:
zhangho@ucar.edu