Liu, J. P., X. J. Yuan, D. G. Martinson and D. Rind, 2004: Re-evaluating Antarctic sea-ice variability and its teleconnections in a GISS global climate model with improved sea ice and ocean processes. International Journal of Climatology, 24(7): 841-852.
This study re-evaluated simulated Antarctic sea-ice variability and its teleconnections in a NASA Goddard Institute for Space Studies (GISS) coupled global climate model (CGCM) with improved sea-ice and ocean processes. With the improvements to the parameterizations of sea-ice dynamics and thermodynamics and of sub-grid-scale ocean processes, the new version of the GISS/CGCM does indeed do a better job in the representations of the local/regional ice-ocean interactions with regard to (1) the seasonal distributions of the Antarctic sea-ice edges (SIE), and (2) the vertical temperature and salinity structure in the upper Southern Ocean and surface air temperature (SAT) climatology in the southern high latitudes compared with the control version. However, these encouraging local/regional improvements do not extend to the simulations of the polar and extrapolar climate teleconnections. There is no obvious change to the simulations of the dominant spatial covarying patterns of the SAT variability on either the regional (southern high latitudes) or global scales. The simulated teleconnections between Antarctic SIE and global SAT still show the weak El Nino-southern oscillation like correlation pattern in the eastern tropical Pacific, though the new version generates a stronger tropical Indian component. Some dominant observed teleconnection patterns in the western extreme of the tropical Pacific and over the tropical continents (in-phase relationship between tropical South America and Africa) are still not well represented or are missed in the Antarctic SIE and global SAT lead/lag correlation maps and the empirical orthogonal function analysis on those correlation maps. The possible causes of the weak teleconnections in the improved GISS/CGCM are briefly discussed. Copyright (C) 2004 Royal Meteorological Society.
Yuan, X. J., D. G. Martinson and Z. Q. Dong, 2004: Upper ocean thermohaline structure and its temporal variability in the southeast Indian Ocean. Deep-Sea Research Part I-Oceanographic Research Papers, 51(2): 333-347.
We examine the upper ocean thermohaline structure in the southeast Indian Ocean and its temporal variability based on XBT/XCTD observations from four cruises across the Southern Ocean from Fremantle, Australia to Prydz Bay, Antarctica. The transects were occupied in March 1998, November 1998, March 2000 and March 2002. Three major fronts-the subtropical front, subantarctic front and polar front-are clearly identified from our surveys and compared with earlier studies. Particularly, two polar fronts, separated by a few degrees of latitude, appear southeast the Kerguelen Plateau. The primary polar front is characterized by a strong horizontal thermal gradient extending deep in the water column, while the secondary polar front is identified by the 2degreesC isotherm at T-min depth and has a relatively shallow frontal expression. Dynamic height across the Antarctic Circumpolar Current (ACC) was calculated for the transects in 2000 and 2002. With a negligible yearly variation in the total transport across the ACC, the higher sample density in 2002 reveals more detailed structure of the ACC: two jets associated with the SAF and primary polar front are embedded within the broad ACC.
The database was updated today.