Climate

1
Climate Atmospheric history from the Vostok ice
core, Antarctica

• Marianne den Ouden
• Polar Meteorology 2004

2
Overview

• Introduction
• Paleoclimatology
• Ice cores
• Results from the Vostok ice core
• Summary

3
Introduction

• Vostok research
• Paper
• Records cover gt400 kyr
• Features 4 climate cycles
• Change in
• Local temperature
• Dust content
• Natrium concentration
• Greenhouse gasses CO2 and CH4

4
Paleoclimatology

• Timescales/Nomeclature
• Climate Records
• Orbital Forcing (Milankovitch cycles)
• Precession
• Obliquity
• Eccentricity
• Glacial-interglacial Cycles

5
Geological Time scale
6
Paleoclimatology

• Timescales/Nomeclature
• Climate Records
• Orbital Forcing (Milankovitch cycles)
• Precession
• Obliquity
• Eccentricity
• Glacial-interglacial Cycles

7
Milankovitch Cycles
8
Paleoclimatology

• Timescales/Nomeclature
• Climate Records
• Orbital Forcing (Milankovitch cycles)
• Precession
• Obliquity
• Eccentricity
• Glacial-interglacial Cycles

9
Ice Cores

• Drilling
• Processing
• Obtained Data
• Deuterium/Oxygen 18
• Aerosols (dust/Sodium)
• Greenhouse gasses
• Interpretation
• timescale

10
Vostok ice core

• Ice record
• Four climate cycles in a sample gt400 kyr at a
  depth of 3310m
• Variations in deuterium (local temperature),
  dust content, Natrium concentration, greenhouse
  gasses CO2 and CH4, oxygen 18 isotope (global ice
  volume)
• Climate and Atmospheric trends
• Temperature
• Aerosols
• Greenhouse gasses

11
Temperature

• Amplitude of glacial-interglacial is 12C
• Sawtooth sequence

12
Vostok time series and insolation
13
Spectral properties of the Vostok time series
14
Aerosols

• Sodium/dust
• Maximum aerosols during glacial periods
• Cyclonic activity
• Continental aridity

15
Vostok time series and ice volume
16
Spectral properties of the Vostok time series
17
Greenhouse gases

• Main trend CO2 and CH4 similar for each cycle
• Temperature and CH4 decrease are in phase
• CO2 decrease lags
• Strong correlation between CO2 and CH4 and
  temperature records

18
Vostok time series and insolation
19
Spectral properties of the Vostok time series
20
Conclusions

• Climate in constantly in state of change
• Same sequence of climate forcings during each
  termination
• Orbital forcing
• Two amplifiers
• Greenhouse gases
• Deglaciation via ice-albedo feedback
• Current conditions unprecedented