october 2016: current fesd projects at...
TRANSCRIPT
october 2016: current FESD projects at Columbia
a paper on metrics of tropical expansion in the Southern Hemisphere A Solomon, LM Polvani, DW Waugh and S. Davis: Contrasting upper and lower atmospheric metrics of tropical expansion in the Southern Hemisphere, GRL, in press
a paper the ozone depletion and AA surface energy balance
G. Chiodo, LM Polvani and M Previdi: Large surface radiative forcing due to the ozone hole offsetby high climatological albedo and snowfall trends over Antarctica, Env. Res. Lett., in review
a paper the coupled stratospheric ozone chemistry and jet shifts
G. Chiodo and L.M. Polvani: Significant impact of interactive stratospheric ozone chemistry on the response of the Southern Hemispheric circulation to increased greenhouse gases, GRL, in review
a paper on ozone depletion and carbon uptake in the Southern Ocean in the Large Ensemble runs (Lovenduski & Polvani, in preparation)
a paper on ozone depletion and AA sea ice in the Large Ensemble runs(Landrum, Holland & Polvani, in preparation)
Mark England is working on understanding the interplay betweenAntarctic sea ice and the Amundsen Sea Low
we have lost Ari Solomon, and we could use a new postdoc… suggestions?
FESD: Ozone and Climate JHU Activities October 2016
The Transient Response of the Southern Ocean to Ozone Depletion in GFDL model:
• Paper 1 published (Seviour et al. “The Transient Response of the Southern Ocean to Stratospheric Ozone Depletion”).
• Paper 2 revisions submitted (Seviour et al. “ … Regional responses and physical mechanisms”).
• New set of ozone perturbation runs started with configuration of GFDL model without
large convective cycles. – Just started.
• Analysis of influence of daily/monthly ozone on ocean response in WACCM and GFDL models.
Ocean Heat-Carbon-Biogeochemistry-Ice variability • Analysis of Heat and Carbon variability in series of GFDL runs being written up
(Thomas et al in prep.)
• Analysis of global impacts of changes in Southern Ocean convection (Cabre, Marinov and Gnanadesikan, subm.)
• Analysis of marginal change in anthropogenic carbon uptake associated with ozone change (Gnanadesikan et al., in prep., in conversations with Lovenduski about joint paper)
• Ragen,S., M.A. Pradal and Gnanadesikan, Impact of lateral tracer mixing on the transport
of the Circumpolar Current, in prep. for J. Phys. Oceanogr.
• The Arctic-Subarctic sea ice system is entering the seasonal regime, Haine & Martin, submitted to Scientific Reports.
SH Tropospheric Circulation
• Robustness of the simulated tropospheric response to ozone depletion – Seviour et al. paper to be resubmitted.
• Contrasting Upper and Lower Atmospheric Metrics of Tropical Expansion in the Southern Hemisphere (Columbia lead): A. Solomon et al in press.
Miscellaneous
• Stewart, K. D. and T. W. N. Haine. Thermobaricity in the transition zones between alpha and beta oceans. J. Phys. Oceanogr., 46, 1805–1821, 2016. 10.1175/JPO-D-16-0017.1.
October 2016 FESD Update – NCAR CGD Summary: Papers under review: Holland, Landrum, Kostov, Marshall, SensiLvity of AntarcLc sea ice to the SAM in coupled climate models, Climate Dynamics, accepted with minor revisions Papers in preparaLon – in the outline stage, geOng input from co-‐authors 1. Influence of winds on western Ross Sea ice cover: Seasonal lags and explained trends • Results discussed at June FESD meeLng • ObservaLonal analysis of factors driving ice variaLons in the western Ross Sea • Targeted for Nature Geosciences
2. The influence of ozone on regional and seasonal changes in AntarcLc sea ice (Landrum, Holland, Polvani) • Analysis of the regional and seasonal sea ice response in CESM-‐LE and fixed ozone runs • How this is related to ozone-‐driven Amundsen Sea Low changes • Targeted for GRL
Studies in progress: Sea ice response to SAM variaLons in CESM using models with difference ocean configuraLons
-‐ Talk to be given at model hierarchies meeLng in Princeton in 2 weeks
CESM-‐LE Ensemble Mean
Sea ice change that is a]ributable to changes in the Amundsen Sea Low.
(Relevant since ozone loss
contributes to ASL deepening)
The influence of ozone on regional and seasonal
changes in AntarcLc sea ice Regional and Seasonal Changes in Sea
Ice
(1996-‐2005) minus (1955-‐1964)
CESM Ozone Influence
(CESM-‐LE minus fO3)
CESM-‐LE Ensemble Mean
Sea ice change that is a]ributable to changes in the Amundsen Sea Low.
(Relevant since ozone loss
contributes to ASL deepening)
The influence of ozone on regional and seasonal
changes in AntarcLc sea ice
Zonal Asymmetry in the Regional and Seasonal Changes in Sea Ice
(1996-‐2005) minus (1955-‐1964)
CESM
Ozone Influence (CESM-‐LE minus fO3)
InvesLgaLng the spaLal and Lme-‐lagged sea ice response to the SAM in CESM simulaLons
SOM Impulse Response
0 100 200 300Longitude
-2
0
2
4
6
8
10
Lag
PI Impulse Response
0 100 200 300Longitude
-2
0
2
4
6
8
10
Lag
PI-SOM Impulse Response
0 100 200 300Longitude
-2
0
2
4
6
810
Lag
Imp Response % Explained by SOM
0 100 200 300Longitude
-2
0
2
4
6
810
Lag
-2.0-2.0
-2.0-1
.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0 0.00.0
0.0 0.00.
0 0.0 0.0 0.
0
0.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
2.0
2.0
3.04.0
• IniLal ice change in response to SAM has some similariLes regardless of ocean component • When ocean dynamics is present, there are indicaLons that ice loss anomalies are
advected eastward; speed is consistent with mean ocean circulaLon • What gives rise to iniLal ice loss around 80-‐180E and 300-‐360E? How do ocean dynamics
modify the iniLal anomalies? Why do posiLve ice anomalies have shorter lifespan?
Regression of ice area on DJF SAM Slab Ocean Model IntegraLons
Regression of ice area on DJF SAM Fully Coupled Model IntegraLons
October 2016 FESD Update – NCAR ACOM Summary: Papers in preparaLon – in the outline stage, geOng input from co-‐authors 1. Several paper with the Solomon group (see their update).
Studies in progress: RevisiLng Southern Hemisphere Polar Stratospheric Temperature Trends in WACCM: the Role of Dynamical Forcing (N. Calvo, R. Garcia, D. Kinnison).
Background • Aher the SPaRC CCMVal2 Model intercomparison, there was a significant effort to
improve the representaLon of polar chemical processes in WACCM (Wegner et al., JGR, 2013). Specifically the processes that form polar stratospheric clouds (STS SAD, de-‐hydraLon, and de-‐nitrificaLon) were improved. The evaluaLon of polar ozone depleLon was later conducted and published in Solomon et al., JGR. 2015.
• IniLal simulaLon for SPaRC/IGAC CCMI with this new chemical package showed that the model ozone depleLon was more sensiLve to the absolute temperature in winter/spring (work shown at the Columbia FESD meeLng).
• A new orographic parameterizaLon was developed for WACCM-‐CCMI which reduced the cold temperature bias and the resulLng ozone depleLon was well represented (Garcia et al., JAS, in press).
(a) trend T 65-90S REF-ORO 1969-1998 (b) trend O3 65-90S REF-ORO 1969-1998(a) trend T 65-90S REF 1969-1998 (b) trend O3 65-90S REF 1969-1998
Without addiLonal orographic forcing. With addiLonal orographic forcing.
-‐4.4±2.8 K per decade -‐6.2±2.5 K per decade
<= Young et al., 2013, ObservaLon: -‐4.1±2.4 K per decade.
Conclusion: ExaminaLon of the terms of the thermodynamic balance reveal that the reduced trend is due to enhanced Brewer-‐Dobson circulaLon of the SH polar cap. Thus larger adiabaLc warming in Nov. and Dec. associated with enhanced orographic GW forcing.