Can arctic sea ice summer melt be accelerated by changes in spring cloud properties
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Can Arctic Sea Ice Summer Melt be Accelerated by Changes in Spring Cloud Properties?. I. Gorodetskaya 1 , B. Tremblay 1,2 , B. Liepert 1 , M. Cane 1. 1 Lamont-Doherty Earth Observatory, New York. 2 McGill University, Montreal. yes. surface radiative fluxes. atmosphere.

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Can arctic sea ice summer melt be accelerated by changes in spring cloud properties

Can Arctic Sea Ice Summer Melt be Accelerated by Changes in Spring Cloud Properties?

I. Gorodetskaya1, B. Tremblay1,2, B. Liepert1, M. Cane1

1Lamont-Doherty Earth Observatory, New York

2McGill University, Montreal


Can arctic sea ice summer melt be accelerated by changes in spring cloud properties
yes Spring Cloud Properties?


Surface radiative fluxes
surface Spring Cloud Properties?radiative fluxes

atmosphere

Data: SHEBA Atmospheric

Surface Fluxes Group


Cloud phase and long wave

February Spring Cloud Properties?

March

April

Cloud phase and long-wave:

WINTER->SPRING


Cloud phase and long wave1
Cloud phase and long-wave: Spring Cloud Properties?

SPRING->SUMMER

May

June

July


Cloud lw forcing cfl as a function of cloud properties
Cloud LW forcing (CFL) as a function of cloud properties Spring Cloud Properties?

Chen, Aires, Francis, Miller, J Climate 2006


Liquid water path data and models
Liquid water path: data and models Spring Cloud Properties?

Gorodetskaya et al, accepted to J Climate


Total variance in the perennial ice edge attributable to anomalies in forcing parameters 1980 2004
Total variance in the perennial ice edge attributable to anomalies in forcing parameters, 1980-2004

J. A. Francis and E Hunter

also see: Francis, Hunter, Key, Wang, JRL 2005


Spring large positive trend

Cloud cover over the Arctic Ocean: anomalies in forcing parameters, 1980-2004

- Spring: large positive trend

- Summer: no trend …

Schweiger, GRL 2004



Changes in arctic white bars annual mean sea ice extent at the end of the 21st century
Changes in Arctic (white bars) fluxannual mean sea ice extent at the end of the 21st century

Arzel, Fichefet, Goosse, Ocean Modelling 2006


Ccsm3 predicts a large increase in the arctic annual mean downwelling lw flux in the 21 st century
CCSM3: predicts a large increase in the Arctic annual mean downwelling LW flux in the 21st century


Ccsm3 predicts a large increase in the arctic annual mean downwelling lw flux in the 21 st century1
CCSM3: predicts a large increase in the Arctic annual mean downwelling LW flux in the 21st century


Winter spring
Winter& downwelling LW flux SPRING!

increase in

cloud liquid

water path:

increase in

LW flux down:


Total downwelling flux difference between the last and first decades of 21 st century
Total downwelling flux downwelling LW flux difference between the last and first decades of 21st century


0 layer thermodynamics model sea ice thickness and concentration evolution
0-layer thermodynamics model: downwelling LW flux sea ice thickness and concentration evolution

Ta - from NP drifting stations (Lindsay, J Climate 1998)

LW, SW

LW, SW, Fsens, Flat

Fsens(Ta-Ti),

Flat

Ti

Fc

ice: A,h

Tb=-1.8



Sea ice thickness change
Sea ice thickness change: downwelling LW and SW fluxes


Conclusions and outlook
conclusions and outlook downwelling LW and SW fluxes

  • Clouds increase: Apr 21%, May 12% (1980-2004) => Arctic Ocean gains ~15 W/m2 more

    LW radiation (TOVS data)

  • NCAR CCSM3:

  • Arctic - more liquid clouds in 2xCO2 world

  • spring cloud LW warming overwhelms SW cooling

  • with the above cloud response alone (LW forcing strongest in winter and spring), a 1D ice model reduces an equilibrium sea ice thickness from 4.5 to 2.5 m

  • positive feedbacks not included!

    e.g., snow(T) -> surface albedo


Arctic sea ice summer melt can be accelerated by an increase in spring cloud liquid water path

Photo from Peter Minnett downwelling LW and SW fluxes

Arctic Sea Ice Summer Melt can be accelerated by an increase inSpring cloud liquid water path...

Big Thanks: Yonghua Chen, Jennifer Francis,

Kirstie Stramler, Martin Vancoppenolle,

Richard Cullather