Paleoceanography

(top) El Niño and(bottom) La Niña skill error (1σ) as percentage of total skill for pseudoproxy data. Error was calculated using a Monte Carlo simulation (100 iterations) of pseudoproxy skill at each grid point, with random analytical uncertainty added to SST and SSS data sets prior to constructing the forward model. Areas that exceed 100% should not be interpreted, as the error level exceeds the skill level in that region.

The top - bottom age difference for (a) Simulation A-eq and (b) Simulation B-eq. Units in years.

Sea ice fraction and surface air temperature during the austral winter season for the Dop-1x, Dop-2x and Dop-3x simulations.

Location of core V21–30 with respect to annual SST anomalies (January through December) during the (top) 1997 El Niño and (bottom) 2007 La Niña (from Global Ocean Data Assimilation System, accessed at http://www.cpc.ncep.noaa.gov/products/GODAS/monthly.shtml).

Key steps in the marine N cycle typically recorded in the nitrogen isotopic composition of marine sediments. Estimates of isotopic enrichment factors for the individual transformations are noted. The green shaded area represents suboxic water columns where denitrification occurs (modified from Sigman et al. [2009]).