Arctic Climate: Past and Present

3,24

MB

40

stron

2363

ID

Intergovernmental Panel on Climate Change

2005

rok

Contents

Summary . .22

2.1. Introduction . .22

2.2.Arctic atmosphere .23

2.2.1. Climatology .24

2.2.2.Variability modes .24

2.2.2.1.Arctic/North Atlantic Oscillation . .24

2.2.2.2. Pacific Decadal Oscillation .26

2.3. Marine Arctic . .26

2.3.1. Geography . .26

2.3.2. Influence of temperate latitudes . .27

2.3.3.Arctic Ocean . .29

2.3.4. Sea ice .30

2.4.Terrestrial water balance . .31

2.4.1. Permanent storage of water on land . .31

2.4.2. Hydrology of freshwater in the Arctic . .31

2.5. Influence of the Arctic on global climate .32

2.5.1. Marine connections . .32

2.5.1.1. Ice-albedo feedback to warming and cooling . .33

2.5.1.2. Freshwater feedback to poleward transport of heat and

freshwater .33

2.5.2. Sea level .33

2.5.3. Greenhouse gases . .34

2.6.Arctic climate variability in the twentieth century .34

2.6.1. Observing systems and data sources .34

2.6.2.Atmospheric changes .35

2.6.2.1. Land-surface air temperature .35

2.6.2.2. Precipitation . .39

2.6.2.3. Sea-level pressure . .42

2.6.2.4. Other variables .42

2.6.3. Marine Arctic .44

2.6.4.Terrestrial system . .45

2.7.Arctic climate variability prior to 100 years BP . .46

2.7.1. Pre-Quaternary Period . .46

2.7.2. Quaternary Period .47

2.7.3. Last interglacial and glaciation . .48

2.7.3.1. Last interglacial:The Eemian . .48

2.7.3.2. Last glaciation:Wisconsinan/ Weichselian .48

2.7.4. Last glacial/interglacial transition through to mid-Holocene .49

2.7.4.1. Last glacial/interglacial transition . .49

2.7.4.2. Early to mid-Holocene . .50

2.7.5. Last millennium . .52

2.7.6. Concluding remarks . .54

2.8. Summary and key findings .54

Acknowledgements . .55

References . . .55