Rs. Keir, ARE ATMOSPHERIC CO2 CONTENT AND PLEISTOCENE CLIMATE CONNECTED BY WIND-SPEED OVER A POLAR MEDITERRANEAN-SEA, Global and planetary change, 8(1-2), 1993, pp. 59-68
Dust and sea-salt records in polar ice cores indicate that the climate
has been windier during ice-ages, and therefore the rate of gas excha
nge between the atmosphere and ocean should be greater in glacial peri
ods. Increased gas exchange between the atmosphere and poleward-advect
ed, sinking cold water due to higher wind speeds could make the solubi
lity pump more efficient, and this would decrease atmospheric CO2. To
illustrate how this might contribute to atmospheric CO2 change over th
e last 150 kyr, the marine Na-concentration in the Vostok ice core is
used as a logarithmic proxy for relative wind speed, from which gas pi
ston velocities relative to the present are estimated. The effect of t
he cold water piston velocity on atmospheric CO2 is then calculated ac
cording to an atmosphere-surface ocean box model. As a result, the sol
ubility pump lowers atmospheric CO2 about 50 ppm during oxygen isotope
stages 2-4 and about 40 ppm during stage 5a-d. Unlike various nutrien
t rearranging mechanisms, the solubility pump produces little fraction
ation of carbon isotopes between the surface and deep ocean. Combining
wind-induced solubility and nutrient-based effects, using DELTAdeltaC
-13 in deep-sea core V19-30 as a proxy of the latter, produces a recor
d of atmospheric CO, which is similar to that observed in the Vostok i
ce core.