Influence of the boreal spring Southern Annular Mode on summer surface air temperature over northeast China

2014 ◽  
Vol 16 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Fei Zheng ◽  
Jianping Li ◽  
Robin T. Clark ◽  
Ruiqing Ding ◽  
Fei Li ◽  
...  
Keyword(s):  
Air Temperature ◽  
Northeast China ◽  
Surface Air Temperature ◽  
Southern Annular Mode ◽  
Annular Mode ◽  
Boreal Spring

scholarly journals Influence of the Southern Annular Mode on the sea ice-ocean system: the role of the thermal and mechanical forcing

Ocean Science ◽  
2005 ◽  
Vol 1 (3) ◽  
pp. 145-157 ◽  
Author(s):  
W. Lefebvre ◽  
H. Goosse
Keyword(s):  
Sea Ice ◽  
Air Temperature ◽  
Wind Stress ◽  
Southern Annular Mode ◽  
Weddell Sea ◽  
The Other ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Annular Mode ◽  
The Antarctic

Abstract. The global sea ice-ocean model ORCA2-LIM is used to investigate the impact of the thermal and mechanical forcing associated with the Southern Annular Mode (SAM) on the Antarctic sea ice-ocean system. The model is driven by idealized forcings based on regressions between the wind stress and the air temperature at one hand and the SAM index the other hand. The wind-stress component strongly affects the overall patterns of the ocean circulation with a northward surface drift, a downwelling at about 45° S and an upwelling in the vicinity of the Antarctic continent when the SAM is positive. On the other hand, the thermal forcing has a negligible effect on the ocean currents. For sea ice, both the wind-stress (mechanical) and the air temperature (thermal) components have a significant impact. The mechanical part induces a decrease of the sea ice thickness close to the continent and a sharp decrease of the mean sea ice thickness in the Weddell sector. In general, the sea ice area also diminishes, with a maximum decrease in the Weddell Sea. On the contrary, the thermal part tends to increase the ice concentration in all sectors except in the Weddell Sea, where the ice area shrinks. This thermal effect is the strongest in autumn and in winter due to the larger temperature differences associated with the SAM during these seasons. The sum of the thermal and mechaninal effects gives a dipole response of sea ice to the SAM, with a decrease of the ice area in the Weddell Sea and around the Antarctic Peninsula and an increase in the Ross and Amundsen Seas during high SAM years. This is in good agreement with the observed response of the ice cover to the SAM.

scholarly journals The Impact of Tropical Indian Ocean Variability on Summer Surface Air Temperature in China

2011 ◽  
Vol 24 (20) ◽  
pp. 5365-5377 ◽  
Author(s):  
Kaiming Hu ◽  
Gang Huang ◽  
Ronghui Huang
Keyword(s):  
Indian Ocean ◽  
Air Temperature ◽  
South China ◽  
Northeast China ◽  
Surface Air Temperature ◽  
Vertical Motion ◽  
Tropical Indian Ocean ◽  
Ocean Basin ◽  
Sst Anomalies ◽  
Anomalous Cyclone

Abstract Evidence is presented that the boreal summer surface air temperature over south China and northeast China is remotely influenced by the Indian Ocean Basin mode (IOBM) sea surface temperature (SST) anomalies. Above-normal temperature in south China and below-normal temperature in northeast China correspond to a simultaneous Indian Ocean Basin warming. The teleconnection from Indian Ocean SST anomalies to China summer surface air temperature is investigated using observations and an atmospheric general circulation model (AGCM). The results herein indicate that the tropical Indian Ocean Basin warming can trigger a low-level anomalous anticyclone circulation in the subtropical northwest Pacific and an anomalous cyclone circulation in midlatitude East Asia through emanating a baroclinic Kelvin wave. In south China, the reduced rainfall and downward vertical motion associated with the anomalous low-level anticyclone circulation lead to above-normal summer surface air temperature. In northeast China, by contrast, upward vertical motion associated with the anomalous cyclone leads to below-normal summer surface air temperature.

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

2009 ◽  
Vol 22 (13) ◽  
pp. 3751-3768 ◽  
Author(s):  
Alexey Yu Karpechko ◽  
Nathan P. Gillett ◽  
Gareth J. Marshall ◽  
James A. Screen
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Temperature Response ◽  
Coupled Model ◽  
Surface Air Temperature ◽  
Southern Annular Mode ◽  
Climate Impacts ◽  
Sea Ice Concentration ◽  
Annular Mode ◽  
Simulated Precipitation

Abstract The southern annular mode (SAM) has a well-established impact on climate in the Southern Hemisphere. The strongest response in surface air temperature (SAT) is observed in the Antarctic, but the SAM’s area of influence extends much farther, with statistically significant effects on temperature and precipitation being detected as far north as 20°S. Here the authors quantify the ability of the Coupled Model Intercomparison Project, phase 3 (CMIP3) coupled climate models to simulate the observed SAT, total precipitation, sea surface temperature (SST), and sea ice concentration responses to the SAM. The models are able to simulate the spatial pattern of response in SAT reasonably well; however, all models underestimate the magnitude of the response over Antarctica, both at the surface and in the free troposphere. This underestimation of the temperature response has implications for prediction of the future temperature changes associated with expected changes in the SAM. The models possess reasonable skill in simulating patterns of precipitation and SST response; however, some considerable regional deviations exist. The simulated precipitation and SST responses are less constrained by the observations than the SAT response, particularly in magnitude, as significant discrepancies are detected between the responses in the reference datasets. The largest problems are identified in simulating the sea ice response to the SAM, with some models even simulating a response that is negatively correlated with that observed.

scholarly journals Quantifying Southern Annular Mode paleo-reconstruction skill in a model framework

2021 ◽  
Vol 17 (5) ◽  
pp. 1819-1839
Author(s):  
Willem Huiskamp ◽  
Shayne McGregor
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Surface Air Temperature ◽  
Southern Annular Mode ◽  
Network Size ◽  
Model Framework ◽  
Annular Mode ◽  
The Impact ◽  
Broad Region

Abstract. Past attempts to reconstruct the Southern Annular Mode (SAM) using paleo-archives have resulted in records which can differ significantly from one another prior to the window over which the proxies are calibrated. This study attempts to quantify not only the skill with which we may expect to reconstruct the SAM but also to assess the contribution of regional bias in proxy selection and the impact of non-stationary proxy–SAM teleconnections on a resulting reconstruction. This is achieved using a pseudoproxy framework with output from the GFDL CM2.1 global climate model. Reconstructions derived from precipitation fields perform better, with 89 % of the reconstructions calibrated over a 61 year window able to reproduce at least 50 % of the inter-annual variance in the SAM, as opposed to just 25 % for surface air temperature (SAT)-derived reconstructions. Non-stationarity of proxy–SAM teleconnections, as defined here, plays a small role in reconstructions, but the range in reconstruction skill is not negligible. Reconstructions are most likely to be skilful when proxies are sourced from a geographically broad region with a network size of at least 70 proxies.

The Importance of Atmospheric Dynamics in the Northern Hemisphere Wintertime Climate Response to Changes in the Earth’s Orbit

2005 ◽  
Vol 18 (9) ◽  
pp. 1315-1325 ◽  
Author(s):  
Alex Hall ◽  
Amy Clement ◽  
David W. J. Thompson ◽  
Anthony Broccoli ◽  
Charles Jackson
Keyword(s):  
Northern Hemisphere ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Atmospheric Dynamics ◽  
Orbital Forcing ◽  
Last Interglacial ◽  
Cold Temperatures ◽  
Annular Mode ◽  
Northern Annular Mode ◽  
Orbital Excitation

Abstract Milankovitch proposed that variations in the earth’s orbit cause climate variability through a local thermodynamic response to changes in insolation. This hypothesis is tested by examining variability in an atmospheric general circulation model coupled to an ocean mixed layer model subjected to the orbital forcing of the past 165 000 yr. During Northern Hemisphere summer, the model’s response conforms to Milankovitch’s hypothesis, with high (low) insolation generating warm (cold) temperatures throughout the hemisphere. However, during Northern Hemisphere winter, the climate variations stemming from orbital forcing cannot be solely understood as a local thermodynamic response to radiation anomalies. Instead, orbital forcing perturbs the atmospheric circulation in a pattern bearing a striking resemblance to the northern annular mode, the primary mode of simulated and observed unforced atmospheric variability. The hypothesized reason for this similarity is that the circulation response to orbital forcing reflects the same dynamics generating unforced variability. These circulation anomalies are in turn responsible for significant fluctuations in other climate variables: Most of the simulated orbital signatures in wintertime surface air temperature over midlatitude continents are directly traceable not to local radiative forcing, but to orbital excitation of the northern annular mode. This has paleoclimate implications: during the point of the model integration corresponding to the last interglacial (Eemian) period, the orbital excitation of this mode generates a 1°–2°C warm surface air temperature anomaly over Europe, providing an explanation for the warm anomaly of comparable magnitude implied by the paleoclimate proxy record. The results imply that interpretations of the paleoclimate record must account for changes in surface temperature driven not only by changes in insolation, but also by perturbations in atmospheric dynamics.

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