Climate Impacts of the Southern Annular Mode Simulated by the CMIP3 Models

Karpechko, Alexey Yu.; Gillett, Nathan P.; Marshall, Gareth J.; Screen, James A.

doi:10.1175/2009jcli2788.1

Cited by 37 publications

(30 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The correlation is largely zonally symmetric and generally positive in the Southern Ocean, while negative further north and in the interior of Antarctica. This is consistent with the simulated pattern of precipitation anomalies during the SAM's positive phase (Boer Karpechko et al 2009). The correlation is generally positive in the Antarctic Peninsula, especially in the western part, consistent with previous work that the Antarctic Peninsula is generally wetter during the SAM's positive phase.…”

Section: Links To the Samsupporting

confidence: 89%

Why does the Antarctic Peninsula Warm in climate simulations?

Hall

Boé

2011

Clim Dyn

View full text Add to dashboard Cite

The Antarctic Peninsula has warmed significantly since the 1950s. This pronounced and isolated warming trend is collectively captured by 29 twentiethcentury climate hindcasts participating in the version 3 Coupled Model Intercomparison Project. To understand the factors driving warming trends in the hindcasts, we examine trends in Peninsula region's atmospheric heat budget in every simulation. We find that atmospheric latent heat release increases in nearly all hindcasts. These increases are generally anthropogenic in origin, and account for about 60% of the ensemble-mean warming trend in the Peninsula. They are driven primarily by wellunderstood features of the anthropogenic intensification of global hydrological cycle. As sea surface temperature increases, moisture contained in atmospheric flows increases. When such flows are forced to ascend the Peninsula's topography, enhanced local latent heat release results. The mechanism driving the warming of the Antarctic Peninsula is therefore clear in the models. Evidence for a similar mechanism operating in the real world is seen in the increasing snow accumulation rates inferred from ice cores drilled in the Peninsula. However, the relative importance of this mechanism and other processes previously identified as potentially causing the observed warming, such as the recent sea ice retreat in the Bellingshausen Sea, is difficult to assess. Thus the relevance of the simulated warming mechanism to the observed warming is unclear, in spite of its robustness in the models.

show abstract

Section: Links To the Samsupporting

confidence: 89%

Why does the Antarctic Peninsula Warm in climate simulations?

Hall

Boé

2011

Clim Dyn

View full text Add to dashboard Cite

show abstract

“…Such changes alter synoptic weather and the wind forcing of the ocean by the atmosphere, introducing another way for winds to generate multi-decadal changes in sea-ice. Therefore, in addition to the ways in which the occurrence and strength of SAM 37 , ENSO 38 and ice-sheet melt 39 may change, one must also consider how changes in the synoptic weather patterns may alter the future nature of winter sea-ice in the Southern Hemisphere.…”

Section: Discussionmentioning

confidence: 99%

Sources of heterogeneous variability and trends in Antarctic sea-ice

et al. 2015

View full text Add to dashboard Cite

While the Northern Hemisphere sea-ice has uniformly declined over the past several decades, the observed sea-ice in the Southern Hemisphere has exhibited regions of increase and decrease. Here we use a comprehensive set of ocean-sea-ice simulations (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) to elucidate the drivers of the observed heterogeneous sea-ice trends. We show wind variability is an important determinant of the heterogeneous pattern of the variability and trends in Southern Hemisphere sea-ice. Only in the West Pacific region does Southern Annular Mode wind forcing contribute significantly to the trend in sea-ice duration. El Niño Southern Oscillation wind forcing contribution to the sea-ice duration trend is confined to the Atlantic and Pacific. In the Indian Ocean, weather is a significant driver of the sea-ice duration trend. Only in the East Pacific region is wind forcing alone insufficient to give rise to the observed sea-ice decline and must be augmented by warming to reproduce the observations.

show abstract

“…As this cooling is not seen in the historical and historicalGHG models for surface temperature, it is unsurprising that the agreement between the observations and historical experiments is not as good in this region. Jones et al (2013) note that this cooling may be the result of the Southern Annular Mode (Trenberth et al, 2007) but also suggest that there may be forcing contributions to these changes (Karpechko et al, 2009). A further complication is whether low cloud cover plays a role as this is naturally associated with humidity close to the land surface but also with aerosols.…”

Section: Summary Of Temporal Behaviourmentioning

confidence: 99%

Comparison of land surface humidity between observations and CMIP5 models

Dunn¹,

Willett²,

Ciavarella³

et al. 2017

Earth Syst. Dynam.

View full text Add to dashboard Cite

Abstract.We compare the latest observational land surface humidity dataset, HadISDH, with the latest generation of climate models extracted from the CMIP5 archive and the ERA-Interim reanalysis over the period 1973 to present. The globally averaged behaviour of HadISDH and ERA-Interim are very similar in both humidity measures and air temperature, on decadal and interannual timescales.The global average relative humidity shows a gradual increase from 1973 to 2000, followed by a steep decline in recent years. The observed specific humidity shows a steady increase in the global average during the early period but in the later period it remains approximately constant. None of the CMIP5 models or experiments capture the observed behaviour of the relative or specific humidity over the entire study period. When using an atmosphere-only model, driven by observed sea surface temperatures and radiative forcing changes, the behaviour of regional average temperature and specific humidity are better captured, but there is little improvement in the relative humidity.Comparing the observed climatologies with those from historical model runs shows that the models are generally cooler everywhere, are drier and less saturated in the tropics and extra-tropics, and have comparable moisture levels but are more saturated in the high latitudes. The spatial pattern of linear trends is relatively similar between the models and HadISDH for temperature and specific humidity, but there are large differences for relative humidity, with less moistening shown in the models over the tropics and very little at high latitudes. The observed drying in mid-latitudes is present at a much lower magnitude in the CMIP5 models. Relationships between temperature and humidity anomalies (T -q and T -rh) show good agreement for specific humidity between models and observations, and between the models themselves, but much poorer for relative humidity. The T -q correlation from the models is more steeply positive than the observations in all regions, and this over-correlation may be due to missing processes in the models.The observed temporal behaviour appears to be a robust climate feature rather than observational error. It has been previously documented and is theoretically consistent with faster warming rates over land compared to oceans. Thus, the poor replication in the models, especially in the atmosphere-only model, leads to questions over future projections of impacts related to changes in surface relative humidity. It also precludes any formal detection and attribution assessment.

show abstract

Climate Impacts of the Southern Annular Mode Simulated by the CMIP3 Models

Cited by 37 publications

References 54 publications

Why does the Antarctic Peninsula Warm in climate simulations?

Why does the Antarctic Peninsula Warm in climate simulations?

Sources of heterogeneous variability and trends in Antarctic sea-ice

Comparison of land surface humidity between observations and CMIP5 models

Contact Info

Product

Resources

About