Reconstruction of 20th century North American droughts reveals a key role for Atlantic basin temperatures
Here we adopt a statistical approach rooted in a new spatiotemporal analysis of 20th century SST variations and related drought links, which leads to remarkable reconstruction of the major dry and wet episodes over North America; attesting to the extent of the SST influence and facilitating evaluation of the basin contributions.
We find the Atlantic SSTs, tropical and extratropical, to be particularly influential; more than previously indicated, and often, more than the Pacific ones. Statistical drought reconstruction is provided a dynamical foundation from the extraction of SST-circulation links from a nearly century-long circulation record based, in part, on the recent upper-air meteorological analysis of the 1908-1948 period. The links show modulation of moisture transports to be important for drought generation, particularly in the fall. Rudimentary decadal projections based on phase-persistence of multidecadal SST variability suggest wetness over the central-northern Plains in spring-summer and drought conditions in fall.
Pacific and Atlantic SSTs evidently exert a profound influence on North American hydroclimate on decadal timescales, especially, in spring and fall; an influence not fully represented in present-day dynamical models of the atmosphere.