Seasonal Sea Surface Temperature Variability Research Articles

On the processes that control seasonal variations of sea surface temperatures in the tropical Pacific Ocean

In the tropical Pacific Ocean, the cold phase of both interannual and seasonal sea surface temperature variations is characterized by cold waters off the coast of South America and a pronounced equatorial tongue of cold surface waters in the eastern Pacific. The warm phase, in both cases, is marked by the weakening or complete absence of these features. Despite these striking similarities, very different physical processes are dominant on seasonal and interannual time scales. Interannually, a horizontal redistribution of warm surface waters, the dynamical response of the ocean to changes in the winds, is of primary importance. What matters most seasonally are two local processes: seasonal upwelling associated with a divergence of surface 0. currents, and the seasonal modulation of mixing processes, by heat fluxes, that control to what extent upwelling induced by the mean winds influences sea surface temperatures. These results shed light on the different requirements that coupled ocean-atmosphere models should meet if they are to reproduce both seasonal and interannual variability. The results also make a case for measurements, along a meridian in the eastern tropical Pacific, that focus on the relations between sea surface temperature changes, heat flux variations and mixing processes. DOI: 10.1034/j.1600-0870.1994.00011.x

Sea-Surface Temperature from Coral Skeletal Strontium/Calcium Ratios

Seasonal records of tropical sea-surface temperature (SST) over the past 10(5) years can be recovered from high-precision measurements of coral strontium/calcium ratios with the use of thermal ionization mass spectrometry. The temperature dependence of these ratios was calibrated with corals collected at SST recording stations and by (18)O/(16)O thermometry. The results suggest that mean monthly SST may be determined with an apparent accuracy of better than 0.5 degrees C. Measurements on a fossil coral indicate that 10,200 years ago mean annual SSTs near Vanuatu in the southwestern Pacific Ocean were about 5 degrees C colder than today and that seasonal variations in SST were larger. These data suggest that tropical climate zones were compressed toward the equator during deglaciation.

Sea surface temperature variations at coastal sites around New Zealand

Abstract Sea surface temperature (SST) observations from 16 coastal sites around New Zealand are analysed along with some corresponding air temperatures. Day‐to‐day variations in SST show weak periodicity over an 8–16 day range. Air temperatures are generally cooler and short‐term fluctuations have 3–4 times the standard deviation of the SSTs. Seasonal SST variations are described and coastal SSTs are compared with offshore SST data. At Farewell Spit the coastal SSTs were always cooler than offshore SSTs which supports the view that upwelling is persistent in the Cape Farewell region. Inter‐annual variations in SST are found to be correlated with Southern Oscillation atmospheric pressure anomalies. In particular we find that the El Nino phenomenon which is accompanied by warm SSTs in the central and eastern tropical Pacific is also accompanied by lowered SSTs throughout New Zealand's coastal waters.

Simulation of Seasonal Sea Surface Temperature Variations In the North Pacific

North Pacific sea surface temperature variations during the cooling season are simulated using climatological surface boat flux data in conjunction with a deepening mixed layer as determined by a convective adjustment model. Climatological oceanic initial conditions are constructed from the mechanical bathy-thermograph file of the National Oceanographic Data Center. The accuracy of the 90-day simulation depends on the accuracy of the initial and boundary conditions and on the ability to model the deepening of the mixed layer. The neglect of horizontal advection is most critical in the western boundary current region. The ability of such a model to accurately simulate SST changes over a large portion of the North Pacific indicates that the climatological surface heat fluxes computed by Clark (1967) are compatible with the decrease in the heat content of the upper, ocean during this period.

Reproduction in spirorbis (spirorbella) marioni Caullery & Mesnil (polychaeta: Serpulidae)

Reproductive activity in Spirorbis marioni Caullery & Mesnil living on the alga Earegia laevigata Setchell in offshore beds was monitored for thirteen months by collecting freshly beached wrack at La Jolla, California, in 1968–1969. There was production of eggs and brooded embryos throughout the year. An average of 82 % of adults larger than 1 mm greatest diameter were reproductively active at all times. A low but significant correlation was observed between seasonal sea surface temperature variation and seasonal fluctuations in breeding activity. Short term fluctuations in breeding activity were monitored with daily samples for seven months. There were periodic peaks in the spawning of eggs and release of larvae which coincided to a high degree with tidal extremes.