The University of Southampton
University of Southampton Institutional Repository

Time variability of sea surface parameters in the tropical Atlantic using satellite and in situ data

Time variability of sea surface parameters in the tropical Atlantic using satellite and in situ data
Time variability of sea surface parameters in the tropical Atlantic using satellite and in situ data
The influence of the tropical Atlantic Ocean over the climate of Europe, Africa and America is well known today. However, several questions about high-frequency processes in this region remain open. This thesis addresses the characterisation of the diurnal and other short timescale variability of the meteo-ocean variables measured in the tropical Atlantic Ocean by the PIRATA array, as well as derived air-sea heat fluxes. By combining the complementarity and mitigating the disadvantages of using the high temporal resolution of in situ data in conjunction with the excellent spatial coverage of satellite based data, this work also aims to investigate the characteristics of the Tropical Instability Waves in the tropical Atlantic. The satellite data validation process used in this study assesses each of the buoys individually, to take into account possible regional biases.
A complete picture of the mean diurnal cycle and the seasonal variability of the diurnal signal is performed for the first time for the whole tropical Atlantic basin. The SST diurnal signal presents strong characteristics during the respective summer in both hemispheres. However, through the wavelet technique used in this analysis, a significant diurnal signal at the equator could be noticed during the second half of each year, indicating a possible modulation of the diurnal signal by processes with different timescales. It is suggested that Tropical Instability Waves could be one of these processes. The results presented here show that the TIW clearly vary their position and time of activity, depending on the degree of development of the equatorial cold tongue. The most active year analysed in this study was 2001, when the spectral characteristics could be observed as far north as 4oN. The imprints of the TIW are well marked in the wind fields, showing that clearly there are coupled mechanisms associated with the TIW. Moreover, this study confirms that a coupling mechanism suggested for the Pacific Ocean is also applicable to the tropical Atlantic basin. The measurements made by the TMI sensor, in conjunction with the Qscat wind data showed that the atmospheric fields are highly correlated with the SST fields at the timescale associated with the TIW.
The analysis of the cross-scale relationship suggests that the passage of instability waves might affect the diurnal amplitude of SST, skin-SST and latent heat flux. The mechanisms that interact on the eastern and western side of the equatorial Atlantic tend to be distinct, especially due to the local oceanographic and meteorological conditions, and due to the different level of TIW activity.
Caltabiano, A.C.V.
a1390f57-6d8a-4152-94e7-27a0d11fa0b7
Caltabiano, A.C.V.
a1390f57-6d8a-4152-94e7-27a0d11fa0b7

Caltabiano, A.C.V. (2004) Time variability of sea surface parameters in the tropical Atlantic using satellite and in situ data. University of Southampton, Faculty of Engineering Science and Mathematics, School of Ocean and Earth Science, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

The influence of the tropical Atlantic Ocean over the climate of Europe, Africa and America is well known today. However, several questions about high-frequency processes in this region remain open. This thesis addresses the characterisation of the diurnal and other short timescale variability of the meteo-ocean variables measured in the tropical Atlantic Ocean by the PIRATA array, as well as derived air-sea heat fluxes. By combining the complementarity and mitigating the disadvantages of using the high temporal resolution of in situ data in conjunction with the excellent spatial coverage of satellite based data, this work also aims to investigate the characteristics of the Tropical Instability Waves in the tropical Atlantic. The satellite data validation process used in this study assesses each of the buoys individually, to take into account possible regional biases.
A complete picture of the mean diurnal cycle and the seasonal variability of the diurnal signal is performed for the first time for the whole tropical Atlantic basin. The SST diurnal signal presents strong characteristics during the respective summer in both hemispheres. However, through the wavelet technique used in this analysis, a significant diurnal signal at the equator could be noticed during the second half of each year, indicating a possible modulation of the diurnal signal by processes with different timescales. It is suggested that Tropical Instability Waves could be one of these processes. The results presented here show that the TIW clearly vary their position and time of activity, depending on the degree of development of the equatorial cold tongue. The most active year analysed in this study was 2001, when the spectral characteristics could be observed as far north as 4oN. The imprints of the TIW are well marked in the wind fields, showing that clearly there are coupled mechanisms associated with the TIW. Moreover, this study confirms that a coupling mechanism suggested for the Pacific Ocean is also applicable to the tropical Atlantic basin. The measurements made by the TMI sensor, in conjunction with the Qscat wind data showed that the atmospheric fields are highly correlated with the SST fields at the timescale associated with the TIW.
The analysis of the cross-scale relationship suggests that the passage of instability waves might affect the diurnal amplitude of SST, skin-SST and latent heat flux. The mechanisms that interact on the eastern and western side of the equatorial Atlantic tend to be distinct, especially due to the local oceanographic and meteorological conditions, and due to the different level of TIW activity.

Text
Caltabiano_2004_PhD_Thesis.pdf - Other
Download (14MB)

More information

Published date: 2004
Organisations: University of Southampton

Identifiers

Local EPrints ID: 17741
URI: http://eprints.soton.ac.uk/id/eprint/17741
PURE UUID: 91f3b112-8a9e-4c24-86dd-5493db61eee0

Catalogue record

Date deposited: 27 Oct 2005
Last modified: 15 Mar 2024 06:01

Export record

Contributors

Author: A.C.V. Caltabiano

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×