HR: 08:45h
AN: U41B-04    [Abstracts]
TI: Simulation of ENSO Forcings on U.S. Drought by the HadCM3 Coupled Climate Model
AU: * Busby, S J
EM: s.busby@uea.ac.uk
AF: Climatic Researh Unit University of East Anglia, Norwich, NR4 7TJ, United Kingdom
AU: Briffa, K
EM: k.briffa@uea.ac.uk
AF: Climatic Researh Unit University of East Anglia, Norwich, NR4 7TJ, United Kingdom
AU: Osborn, T
EM: t.osborn@uea.ac.uk
AF: Climatic Researh Unit University of East Anglia, Norwich, NR4 7TJ, United Kingdom
AB: The ability of the HadCM3 coupled ocean - atmosphere general circulation model to represent the mechanisms linking the El Niño Southern Oscillation (ENSO) and drought in the U.S. is investigated. Rotated principal components analyses of a self-calibrating Palmer Drought Severity Index (scPDSI) data are used to identify the dominant modes of summer drought variability in the observed climate record (1901-2002), and in a 250-year period of a HadCM3 control run. A similar mode of drought variability is identified in both data sets that is correlated with ENSO variability: a monopolar pattern across the continental interior, centred in the southern states. HadCM3 successfully reproduces the displacement of the mid-latitude jet streams during ENSO events, a mechanism related to U.S. drought variability, but the model appears to be less realistic in its simulation of the influence of Rossby wave teleconections on drought, possibly due to errors in its simulation of ENSO in the equatorial Pacific. Despite this, we conclude that HadCM3's simulation of the link between ENSO and U.S. drought is sufficiently realistic for it to be used in further studies of U.S. drought variability.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 3337 Global climate models (1626, 4928)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4922 El Nino (4522)
DE: 4928 Global climate models (1626, 3337)
SC: Union [U]
MN: 2007 Joint Assembly