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?

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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


Surface radiative fluxes

surface radiative fluxes

atmosphere

Data: SHEBA Atmospheric

Surface Fluxes Group


Cloud phase and long wave

February

March

April

Cloud phase and long-wave:

WINTER->SPRING


Cloud phase and long wave1

Cloud phase and long-wave:

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

Chen, Aires, Francis, Miller, J Climate 2006


Liquid water path data and models

Liquid water path: data and models

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:

- Spring: large positive trend

- Summer: no trend …

Schweiger, GRL 2004


April and may have the largest trends in both cloud and lw flux

April and May have the largest trends in both Cloud % and LW flux

R(LW,CLT)=0.6

TOVS


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

Changes in Arctic (white bars) annual 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&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 fluxdifference between the last and first decades of 21st century


0 layer thermodynamics model sea ice thickness and concentration evolution

0-layer thermodynamics model: 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


Scale the forcing with the ccsm predicted changes in downwelling lw and sw fluxes

Scale the forcing with the CCSM-predicted changes in downwelling LW and SW fluxes


Sea ice thickness change

Sea ice thickness change:


Conclusions and outlook

conclusions and outlook

  • 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

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


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