hansen et al., 2010 reviews of...
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Hansen et al., 2010 Reviews of Geophysics
Hansen et al., 2010 Reviews of Geophysics
Global surface temperature anomalies, 1861-2000.!
data gaps, random errors!
urbanization!
thermometer exposure!
SST bias correction!
Anomalies relative to 1961-1990!
Shading! - dark: distribution! - intermediate: distribution, SST bias-correction, ! !urban bias!
- light: all!
Shading showing uncertainties ! - light (including temp. exposure)! - dark (excluding temp. exposure) !
annual!
21-year smooth!
1950-2004
Upper-air data
Upper-air data
Importance: • interest in entire troposphere • eliminating land-surface influence
Upper-air data Challenges: sensor changes
solar heating warm wake height of balloon burst
Gaffen et al., JGR
Mears et al., 2003 J. of Climate!
Challenges for satellite temperature measurement!• Drift in local equator cross-over times (LECT)!• Orbit decay (falling)!• Instrument body temp.!
Santer et al., 2013 PNAS
Santer et al., 2013 PNAS
1979-2005
Precipitation changes more spatially and seasonally variable than temperature changes!
Tropospheric water vapor increasing!
~ 4% since 1970!
T12 changes with increasing water vapor!T2 remains constant (sensitive to O2)!
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Cryosphere changes!• Snow cover!
• Sea-ice!
• Freeze extent and dates!
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Largest decreases at threshold temperatures (snow-albedo feedback)!
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Snow melt and temperature
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Arctic Sea Ice
Serreze and Francis, 2006 Climatic Change
• general warming in all seasons!!• lengthened melt season!!• initial retreat and thinning of sea ice!
• thermal inertia still mitigates major feedbacks!
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1979-2000 Sept. mean
2007 2008
2009
animation
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Feedbacks
Additional factors
Circulation: • Inflow of Atlantic/
Pacific waters
• Outflow of sea-ice
Is the Dipole Anomaly a major driver to record lows in Arctic summer sea ice extent?
2008 animation
Wang et al. Geophysical Research Letters ���Volume 36, Issue 5, L05706, 6 MAR 2009 DOI: 10.1029/2008GL036706���http://onlinelibrary.wiley.com/doi/10.1029/2008GL036706/full#grl25555-fig-0004
27 Copenhagen Diagnosis, 2009
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Systematic retreat of most mountain glaciers
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Increasing active layer depth over permafrost
Decreasing freeze depth
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Max. extent of seasonally frozen ground
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