Influence of Atlantic sea surface temperatures on persistent drought in North America
- 556 Downloads
This study investigates the relationship between North Atlantic sea surface temperatures (SST) and persistent drought in North America using modern observations, proxy paleo-data, and simulations from multiple climate models. The observational results show that persistent droughts in the Great Plains and the southwest North America are closely related to multidecadal variations of North Atlantic SST (Atlantic Multidecadal Oscillations, AMO). During the AMO warm (cold) phases, most of North America is dry (wet). This relationship is persistent since at least 1567 AD, as based on proxy SST for the North Atlantic and the reconstructed drought index for North America. On centennial timescales, proxy SST records from the North Atlantic and proxy drought records for North America suggest that major periods of AMO-like warm (cold) SST anomalies during the last 7.0 ka correspond to dry (wet) conditions in the Great Plains. The influence of North Atlantic SST on North American droughts is examined using simulations made by five global climate models. When forced by warm North Atlantic SST anomalies, all models captured significant drying over North America, despite some regional differences. Specifically, dry summers in the Great Plains and the southwest North America are simulated by all models. The precipitation response to a cold North Atlantic is much weaker and contains greater disagreement among the models. Overall, the ensemble of the five models could well reproduce the statistical relationship between the dry/wet fluctuations in the North America and North Atlantic SST anomalies. Our results suggest that North Atlantic SSTs are likely a major driver of decadal and centennial timescale circulation, including droughts, in North America. Possible mechanisms that connect North Atlantic SST with North American drought, as well as interactions between North Atlantic and tropical Pacific SST and their relative roles on drought are also discussed.
KeywordsGreat Plain North Atlantic Ocean Palmer Drought Severity Index Southern Great Plain Persistent Drought
We thank the editors, Dr. Ben Kirtman, Dr. Zhunzai Wang and one anonymous reviewer for their comments, which have led to improvement of this manuscript. The model simulations used in this study were carried out as part of a US-CLIVAR drought working group activity supported by NASA, NOAA, and NSF to coordinate and compare climate model simulations forced with a common set of idealized SST patterns. The authors would like to thank NASA’s Global Modeling and Assimilation Office (GMAO) for making the NSIPP1 runs available, the Lamont-Doherty Earth Observatory of Columbia University for making their CCM3 runs available, NOAA’s Climate Prediction Center (CPC)/Climate Test Bed (CTB) for making the GFS runs available, NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) for making the AM2.1 runs available, the National Center for Atmospheric Research (NCAR) for making the CAM3.5 runs available. This work was supported by USDA Cooperative Research Project NEB-40-040, Office of Research at University of Nebraska-Lincoln project WBS 26-6238-0437-001, NASA grant NNG06GE64G and NOAA grant NA09OAR4310188.
- Bacmeister J, Pegion PJ, Schubert SD, Suarez MJ (2000) An atlas of seasonal means simulated by the NSIPP 1 atmospheric GCM, NASA Tech. Memo. No. 104606, volume 17, Goddard Space Flight Center, Greenbelt, MD 20771, 2000Google Scholar
- Campana K, Caplan P (2005) Technical Procedure Bulletin for T382 Global Forecast System. (http://www.emc.ncep.noaa.gov/gc_wmb/Documentation/TPBoct05/T382.TPB.FINAL.htm). Accessed 30 December 2009
- Egan T (2006) The worst hard time. Mariner Books/Houghton Mifflin Company, BostonGoogle Scholar
- Enfield DB, Cid-Serrano L (2010) Secular and multidecadal warmings in the North Atlantic and their relationship with major hurricanes. Int J Climatol 30:174–184Google Scholar
- Hu Q, Feng S (2008) Variation of North American summer monsoon regimes and the Atlantic multidecadal oscillation. J Clim 21:2373–2383Google Scholar
- Kushnir Y, Seager R, Ting M, Naik N, Nakamura J (2010) Mechanisms of tropical Atlantic SST influence on North American hydroclimate variability. J Clim. doi: 10.1175/2010JCLI3172.1