1,720,991 research outputs found
Momentum and modelling. (Book review: Wind stress over the ocean, ed. S.F. Jones and Y. Toba, 2001, Cambridge University Press, 307pp. ISBN 0-521-66243-5)
No full textRole of the Indian Ocean on the southern oscillation, atmospheric circulation indices and monsoon rainfall over India
No full textThe relationship between the sea surface temperature (SST) in a small region (0-5 N; 80-85 E) in the Eastern Equatorial Indian Ocean and Indian monsoon rainfall and monsoon Indices (M1, U200) has been examined. The role of SSTA in the Southern Oscillation and ENSO is also examined. Indian monsoon rainfall is strongly and positively correlated with the SST of November month (0.77; statistically significant at 99% level) of the preceding calendar year. Monsoon indices (M1, U200) are strongly correlated (0.70 and -0.76) with the February SST of the previous year. Summer OLR anomaly field over south Indian Ocean is negatively and strongly (-0.68) correlated with January SST of the previous calendar year. OLR anomalies over south Asian and North African sectors are strongly correlated with the November SST of the previous year. The influence of SST anomalies in the study area on SOI is seen at a lag of 25 months. A sharp fall in SST from September to December in the Eastern Equatorial Indian Ocean is noticed several months before the mature phase of ENSO. The study indicates that the remote forcing from the SST in the eastern equatorial Indian Ocean is playing an important role in the ocean-atmosphere coupling over Pacific and north Australia Indonesia regions, through the eastward propagating low frequency convective systems and the Walker circulation in the zonal wind fiel
Surface heat fluxes in the Western Equatorial Pacific Ocean
No full textEstimates of the components of the surface heat flux in the Western Equatorial Pacific Ocean are presented for a 22-day period, together with a critical analysis of the errors. It is shown that the errors in latent heat, and solar and longwave radiation fluxes, dominate the net heat flux for this period. It is found that the net heat flux into the ocean over the 22-day period is not significantly different from zero. It is also demonstrated that because of the variability in daily averaged values of solar radiation and the latent heat of evaporation, a large number of independent flux measurements will be required to determine with confidence the climatological net heat flux in this region. The variability of latent fluxes over the 22-day period suggest that climatological estimates based on monthly mean observations may lead to a significant underestimate of the latent heat flux
Global changes in mean tidal high water, low water and range
No full textImpacts of extreme sea levels are increasing as the population and infrastructure in coastal zones increases. Extreme high sea levels generally increased at a similar rate to mean sea level through the twentieth century at most sites around the world, suggesting that the same mechanisms are driving both increases. However, the simplicity of this conclusion belies the fact that many mechanisms known to act on the different components of sea level, have been observed to change in local and regional studies. Using a ‘quasi-global’ dataset of sea level records, this paper investigates changes in the tidal component of sea level and shows that changes in mean high and low waters, and hence tidal range, are occurring over long-time scales at many sites around the world. Over half of the selected sites show significant trends in tidal range datums, but no clear spatial patterns of change exist, suggesting that mechanisms are affecting the tide on local scales. Trends are dependent on the tidal datum selected which has wide-ranging practical applications given the variety of uses of tidal datums
Seiches induced by storms in the English Channel
No full textInvestigation of an extreme storm surge event revealed the presence of an oscillation in sea level with a period of 2–6?h. The English Channel is well known for its quarter- and sixth-diurnal tides, and it was expected that these oscillations were simply the result of tide-surge interactions. However, results of model experiments permitted the reproduction of oscillations from wind forcing alone. The forcing used was from an extreme wind event in December 1989. In this article we describe these oscillations, and in particular their spatial characteristics. It is shown that the dominant response is a transverse mode of the English Channel, with minimum amplitude in the central Channel and maximum amplitude in the Baie de Seine and the Golfe de St Malo
Comparison of N. Atlantic heat storage estimates during the Argo period (1999–2010)
No full textOcean heat storage is an essential component of the climate system and there is considerable interest in its accurate evaluation. There are a number of heat storage products produced by many different groups. These products are derived from Argo as well as other platforms, for example XBT and CTD, in the last decade. Here we compare two heat storage estimates for the North Atlantic 0–2000 m from 10° to 70° N. One derived solely from Argo data whilst the other is derived from Argo and other platforms. It is found that there is a positive trend in heat storage over the period 1999–2010. This trend is influenced by a strong air–sea interaction event in 2009–2010, and this reduces the upward trend 1999–2008 identified previously. Both data sets are consistent with each other for the layer 0–1000 m on a timescale of beyond 1 yr. There are significant differences at sub-annual time scales and in the layer 1000–2000 m
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