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IPCC AR4
Klimawandel in den Polargebieten
Peter Lemke
Alfred-Wegener-Institut für Polar- und MeeresforschungBremerhaven
Institut für UmweltphysikUniversität Bremen
IPCC AR4
1. Polargebiete2. Arktis (& Antarktis)3. Neumayer
Inhalt
IPCC AR4
1. Polargebiete2. Arktis (& Antarktis)3. Neumayer
Inhalt
IPCC AR4
Permafrost
Eisschilde
Meereis
Die Polargebiete
IPCC AR4
KlimasystemHohe AlbedoLatente WärmePlastisches MaterialEffektiver Deckel
IPCC AR4
Polargebiete � Globales KlimaNiedere Breiten sind Energie-KollektorenHohe Breiten sind Energie-RadiatorenAusgleich durch Energietransport in Ozean und AtmosphäreEnergietransport wird durch Temperaturgegensätze Äquator – Pol gesteuert
IPCC AR4
Meereis ist eine wichtige Süßwasser-Quelle (Nord-Atlantik, Weddellmeer) und beeinflusst
die
� globale ozeanische Tiefenzirkulation
Polargebiete � Globales Klima
IPCC AR4
Meereis behindert den Wärmeaustausch
IPCC AR4
Tiefen- und Bodenwasserbildung
IPCC AR4
Polargebiete � Globales KlimaGrößte Erwärmung in CO2–Klimaszenarien in Polargebieten (Oberflächen-Energiebilanz; Temperatur – Eisalbedo Feedback)
IPCC AR4
Erwärmung bei CO2 Verdopplung mit konstanter Albedo (FA) und mit Eis-Albedo Feedback (VA) (Hall, 2004)
GFDL model12 IPCC AR4 models
Erwärmung bei CO2 Verdopplung (Jahre 61-80) (Winton, 2006)
Verstärkte Reaktion in Polargebieten
Polargebiete � Globales Klima
IPCC AR4
1. Polargebiete2. Arktis (& Antarktis)3. Neumayer
Inhalt
IPCC AR4
Global gemittelte Temperaturen steigen schneller mit der Zeit
100 0.074�0.018
50 0.128�0.026
Die wärmsten 13 Jahre:1998,2005,2003,2002,2004,2006,
2001,2007,1997,1995,1999,1990,2000
Periode Rate
Jahre �C/Dekade
IPCC AR4
Meereis-Ausdehung
NH Trend: -2.7% pro Dekade
SH Trend: nicht signifikant
IPCC AR4
Temperaturen in den Polargebieten
Trend (letzten 50 Jahre)
TArktis = 1,1°CTglobal = 0,6°C
IPCC AR4
Temperatur von Neumayer
?
IPCC AR4
A Synthesis of Antarctic Temperatures
Linear trends of annual mean surface temperature for the period 1958 and 2002 (Chapmann&Walsh,2005)
Neumayer
Faraday
IPCC AR4
Warme Arktis – kalte Antarktis
IPCC AR4
Ocean Temperatures in Fram Strait
Depth: 250mBased on
monthly means
1997
2008
Time
(years)
IPCC AR4
Atlantic Water (T>2°C) temperature measured by moorings and from summer CTD sections
IPCC AR4
Sept 2007
Arctic Minimum Sea Ice Extent
Summer Minimum Decline(-7.4% per decade)
2008
1978 2007 IPCC AR4
Arctic Minimum Sea Ice Extent
IPCC AR4
Current Arctic Sea Ice Extent30 November 2008
IPCC AR4
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Airborne EM sea ice thickness sounding
EM bird
IPCC AR4
EM induction sea ice thickness sounding
�Ice << �Sea t
Zi = dEM – dLaser
(snow + ice)dEM
dLaser
IPCC AR4
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{C2D3AFE7-85A0-48B7-8490-34E9647EB008}
Beaufort Sea
2007, 2008, 2009
{DB06D91E-9329-4840-81BC-5A09E3713DAE}
Laptev S
2008
{C66EEEFB-2CF0-455B-8486-340E0E634009}
Central Artic/Transpolar drift
{4F889437-29B4-4015-A7EC-96FB9CD7B1F7}
1991, 1996, 1998, 2001, 2004, 2007
{B5600C65-C727-46E9-9A6F-47AA25B8712D}
Lincoln Sea
2004, 2005, 2006, 2008
{556D417A-2DB1-485C-898A-2DE1476232E1}
Svalbard
2003, 2006
{CD0D59E3-7F75-48CD-8B6B-D262C1D1EB79}
Baltic Sea
{661E4FDF-0C59-4ECA-8449-540904B8C5BB}
2003, 2004, 2005, 2007
{06162AEB-1572-44B8-AA58-7E83D52BA2BE}
Framstrait
{35796FC2-4983-48AE-AAD6-FF9F54C7CA06}
2005, 2008
IPCC AR4
2004
Rabenstein, Hendricks,Leinweber, 2007
Ice thickness variability in the Transpolar Drift:1991, 1996, 1998, 2001, 2004 & 2007
Haas, 2004
2007
IPCC AR4
Sea Ice Thickness Lincoln Sea 2004 - 2008
Sea ice drift pattern 2007
Thinner Sea ice in the Lincoln Sea in May 2008 despite 2007 ice dynamics
GREENICE (EU)CryoVEx
IPCC AR4
Simulated Arctic Sea Ice Volume 1990 - 2007
Rüdiger Gerdes (NAOSIM)
1. Polargebiete2. Arktis (& Antarktis)3. Neumayer
Inhalt
IPCC AR4
Neumayer „im Ozonloch“
Neumayer
König-Langlo, AWI IPCC AR4
Ozonprofile 2006
IPCC AR4
IPCC AR4
Zeit-Höhenschnitt von Ozon
König-Langlo, AWI
IPCC AR4
Stratosphärische Ozonabnahme
König-Langlo, AWI IPCC AR4
Zunahme der Globalstrahlung?
Martin Wild et al.
Science 308 2005
From Dimming to Brightening
Decadal Changes in Solar Radiation at Earth´s Surface
IPCC AR4
LWD Trend at Neumayer
König-Langlo, AWI IPCC AR4
Sonnenscheindauer
König-Langlo, AWI
IPCC AR4
Sunshine Duration & no clouds detected
König-Langlo, AWI IPCC AR4
Temperatur unverändert,Globalstrahlung steigt,Gegenstrahlung sinkt,Sonnenscheindauer steigt dramatisch,Wolken werden weniger,
� These: Zirkulationsänderung in der Antarktis kompensiert Effekte der globalen
Trends bei Neumayer
König-Langlo, AWI
Heavy Precipitation and Strong Wind Events on the Antarctic Plateau: Observations from
Kohnen Station, Dronning Maud Land
2nd Antarctic Meteorological Observation, Modeling, and Forecasting Workshop, Rome, Italy, 26-28 June 2007
G. Birnbaum, J. Freitag, G. König-Langlo Alfred Wegener Institute for Polar and Marine Research, Bremerhaven
R. Brauner Deutscher Wetterdienst, Hamburg
C. Tijm-Reijmer Institute for Marine and Atmospheric Research, Utrecht University
Kohnen (75°S, 0°E, 2892 m)
Novo
Neumayer
European Project for Ice Coring in Antarctica (EPICA)
Motivation
High precipitation and strong wind events significantly influence accumulation pattern on the Antarctic Plateau.
Synoptic classification of visually observed high precipitation events at Kohnen Station during summer campaigns from 2001 to 2006
Synoptic ClassificationCategory I: Occluding fronts of eastward moving lows reach the plateau. Category II: Lows or secondary lows which form east of the Greenwich Meridian move to the west (retrograde movement) and frontal clouds influence the plateau.Category III: Large-scale lifting processes due to an upper air low west of Kohnen Station cause snowfall on the plateau.
Frequency
61% of events
30% of events
9% of events
Birnbaum et al. (2006)
Strong Wind Events
Barchan Dune
Impact on snow surface structure
Category IV: Lows which move first from the Antarctic Peninsula / northern Weddell Sea southeastwards, then turn to southwest, and die close to Halley or the Filchner Ice Shelf
Category I: Lows which move first from the Antarctic Peninsula / northern Weddell Sea southeastwards to a position close to Neumayer and then continue moving to the east or northeast
Category II: Lows initially situated off the coast east of the Greenwich Meridian which move to the west (retrograde movement) along the shelf ice edge
Category III: Lows which move from the Antarctic Peninsula / northern Weddell Sea southeastwards to a position close to Neumayer and become stationary there
Synoptic classification of strong wind events Frequency
42% of events
14% of events
12% of events
12% of events
Pattern
TT
TT
T TT
TT
T
T TT
Period 1998-2006: 10 typical synoptic situations identified
Conclusions
Typical synoptic mechanisms for the occurrence of high precipitation and strong wind events could be identified.
Unexpected high number of events due to retrograde moving lows
Number of snow dunes formed per year and conserved in the firn could be explained by a combined analysis of atmospheric observations and model data.
IPCC AR4
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