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Lee-Lueng Fu, Benny Cheng, and Bo Qiu

1. Introduction Intraseasonal variability of sea level, characterized by timescales ranging from a few days to a season and by spatial scales larger than 500 km (roughly the upper bound of the mesoscale), has not been well observed until the advent of precision altimetric missions such as TOPEX/Poseidon (T/P: Fu et al. 1994 ). In situ observations in the Tropics are an exception for several reasons, however. First, most island tide gauges are located in the Tropics, providing a database for

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M. S. McPhaden and R. A. Knox

currentspeed to wave phase speed. The shear flow alters low-frequency Kelvin waves only slightly, introducing a small meridional velocity and a Doppler shift which could affect the speed of baroclinic adjustments in the tropics. At higher frequencies, the Kelvin wave becomes more like an inertio-gravitywave and may appear in velocity records as varicose meanders of the background current.1. Introduction The theory of time-dependent motion in thetropics is distinguished from midlatitude theories bythe

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Alison R. Gray and Stephen C. Riser

profiles) compared to Reid (5932 ship-based stations). In addition, our results employ a direct estimate of the absolute velocities at the reference level, whereas Reid relied on a subjective examination of tracer data to estimate absolute flow. b. Sverdrup balance The wind-derived transport [ V Sv − V E in (5) ], averaged over the entire QuikSCAT period, exhibits the expected large-scale pattern of equatorward flow in the subtropics and tropics and poleward flow in the high latitudes ( Fig. 6

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Victoria J. Coles and Michele M. Rienecker

(e.g., Liu and Zhang 1999 ; Zhang et al. 1998 ; Zhang et al. 1999 ) have suggested that the source lies in linkages between the subtropical and tropical oceans. Near the equator, the oceans adjust rapidly to atmospheric forcing variability due to the rapid Rossby and Kelvin wave propagation speeds. This response timescale has led to the suggestion that decadal variability in the Tropics may have its origins in the subtropics where adjustment through wave processes is slower, and advective

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Annie P. S. Wong and Gregory C. Johnson

heading toward the equator in the South Equatorial Current. The eastern South Pacific is therefore a major formation area for water masses that ventilate the shallow and intermediate layers of the subtropical gyre, which makes this a climatically sensitive region. Some of the SPESTMW ventilation region actually lies within the Tropics ( Fig. 10 ). Even the edge of the Tropics shows considerable variability in sea surface temperature and surface winds on interannual ENSO timescales and on decadal

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Tong Lee, Ichiro Fukumori, Dimitris Menemenlis, Zhangfan Xing, and Lee-Lueng Fu

1. Introduction The Indonesian Throughflow (ITF) is widely known, on average, to carry warm and fresh Pacific waters through the Indonesian archipelago into the Indian Ocean. It is the only channel in the Tropics through which interocean exchange of water masses occurs. Gordon (1986) suggested that the ITF could be important to global ocean thermohaline circulation as it might return the North Atlantic Deep Water that upwelled and warmed in the Pacific back to the Atlantic. Godfrey (1996

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Julian P. McCreary Jr. and Peng Lu

of subtropical water that upwe!ls in thetropics is remotely forced by processes outside the tropics (along Ya). Second, two types of water contributeroughly equally to the STC: unventilated water from the lower-layer western boundary current and ventilatedwater subducted in the subtropical ocean. Third, an internally determined streamline xe(y) determines whetherthe subtropical water approaches the equator entirely in the western boundary current or partly through theinterior ocean. Fourth

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Jane O’Dwyer, Richard G. Williams, Joseph H. LaCasce, and Kevin G. Speer

Tropics, float trajectories have a strong meridional component. d. Defining Q coordinates In the following sections, float displacements are analyzed in terms of a coordinate system aligned along and across Q contours (rather than along lines of longitude, x, and latitude, y ). The coordinates are orientated according to the average ∇ Q over each float group (so variations in the Q gradient over the group are ignored). This simplification appears reasonable given the relatively limited

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Tangdong Qu, Humio Mitsudera, and Toshio Yamagata

properties of the subtropical surface waters will, in due course, first influence the equatorial thermocline and then the surface conditions in the Tropics that in turn affect the circulation in the global atmosphere. The rapid atmospheric links between the Tropics and subtropics, and the slow oceanic links in the reverse direction are hypothesized to be essential in determining the decadal climate variability ( Gu and Philander 1997 ). To further identify the mechanisms of decadal variability in the

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Detlef Stammer and Claus W. Böning

from thealtimeter noise level. Characteristic eddy length scales inferred from Geosat data are linearly related with thedeformation radius of the first baroclinic mode over the whole Atlantic Ocean, except for the equatorial regime( 10-S to 10-N). The data-model comparison indicates that the high-resolution model with horizontal grid size of 113- and2/5- in latitude and longitude is quite capable of simulating observed eddy characteristics in the tropics andsublropies. In mid- and high latitudes

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