North Pacific and North Atlantic sea-surface temperature variability during the Holocene

Abstract

Holocene climate variability is investigated in the North Pacific and North Atlantic realms, using alkenone-derived sea-surface temperature (SST) records as well as a millennial scale simulation with a coupled atmosphere-ocean general circulation model (AOGCM). The alkenone SST data indicate a temperature increase over almost the entire North Pacific from 7 cal kyr BP to the present. A dipole pattern with a continuous cooling in the northeastern Atlantic and a warming in the eastern Mediterranean Sea and the northern Red Sea is detected in the North Atlantic realm. Similarly, SST variations are opposite in sign between the northeastern Pacific and the northeastern Atlantic. A 2300 year long AOGCM climate simulation reveals a similar SST seesaw between the northeastern Pacific and the northeastern Atlantic on centennial time scales. Our analysis of the alkenone SST data and the model results suggests fundamental inter-oceanic teleconnections during the Holocene. r

The origin of the European "Medieval Warm Period"

“…Therefore, on long time-scales as well, the summer temperatures and seasonal contrast of European temperatures has been decreasing. This simulated summer temperature decrease is in good agreement with previous modelling studies (e.g., Masson et al, 1999) and with available proxy records over the European continent which generally exhibit a decrease of summer temperature over the last 6000 years, except for the areas close to the Mediterranean regions (e.g., Davies et al, 2003;Kim et al, 2004).…”

Tropical climate variability from the last glacial maximum to the present

“…Our finding that SSTs throughout the basin were cooler than present at 8 ka is corroborated by two Arabian Sea sites with Holocene alkenone-SST records that demonstrate that SSTs were cooler at 7 ka than they are today (Kim et al, 2004). While the Arabian Sea warmed from the early Holocene to today, sites throughout the subtropical North Atlantic and Mediterranean regions cooled (Marchal et al, 2002;Kim et al, 2004, and references therein).…”

Evidence for Two Distinct Modes of Large-Scale Ocean Circulation Changes over the Last Century

“…The antiphase relation between SST anomalies, in the North Atlantic and the coastal areas in the North Pacific sector, of mode G (Fig. 2d) was associated with the dominant mode of the Northern Hemisphere SST variability over the Holocene (Kim et al 2004) and with THC changes over the last glacial period (Kiefer et al 2001). Furthermore, it was presented as evidence of anoxia events over the past 60 000 years, linked to less upwelling and warmer conditions in the Santa Barbara Basin (Behl and Kennett 1996) that correspond to cold periods recorded in the Greenland ice cap, in agreement with the structure of the G mode (Fig.…”