Tropical Atlantic climate response to low-latitude and extratropical sea-surface temperature: A Little Ice Age perspective uri icon

abstract

  • Proxy reconstructions and model simulations suggest that steeper interhemispheric sea surface temperature (SST) gradients lead to southerly Intertropical Convergence Zone (ITCZ) migrations during periods of North Atlantic cooling, the most recent of which was the Little Ice Age (LIA; 100450 yBP). Evidence suggesting lowlatitude Atlantic cooling during the LIA was relatively small (<1C) raises the possibility that the ITCZ may have responded to a hemispheric SST gradient originating in the extratropics. We use an atmospheric general circulation model (AGCM) to investigate the relative influence of lowlatitude and extratropical SSTs on the meridional position of the ITCZ. Our results suggest that the ITCZ responds primarily to local, lowlatitude SST anomalies and that small cool anomalies (<0.5C) can reproduce the LIA precipitation pattern suggested by paleoclimate proxies. Conversely, even large extratropical cooling does not significantly impact lowlatitude hydrology in the absence of oceanatmosphere interaction.

published proceedings

  • GEOPHYSICAL RESEARCH LETTERS

altmetric score

  • 217.16

author list (cited authors)

  • Saenger, C., Chang, P., Ji, L., Oppo, D. W., & Cohen, A. L.

citation count

  • 9

complete list of authors

  • Saenger, Casey||Chang, Ping||Ji, Link||Oppo, Delia W||Cohen, Anne L

publication date

  • June 2009