@InProceedings{PariseFari:2010:ShWaVa,
author = "Parise, Claudia Klose and Farina, L",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and Mathematics
Institute, UFRGS, Porto Alegre, Brazil",
title = "Short-scale wave variability in the South Atlantic ocean based on
empirical orthogonal function and singular value decomposition",
booktitle = "Posters",
year = "2010",
organization = "The Meeting of the Americas.",
publisher = "AGU",
keywords = "ocean predictability, prediction.",
abstract = "The availability of observational ocean wave data in the South
Atlantic Ocean (SAO) is still very limited. Due to this shortage
of data obtained in situ, numerical modeling has become the most
used tool for the investigation of wave climate in whole world.
Here, the global model WAM was used to simulate waves from June
2006 to July 2007 in order to better understand the wave
variability in short-scale. For this was applied the EOF and SVD
analysis which have found the leading modes of the significant
wave height (Hs), swell, velocity of the wind at height 10 meters
(U10) and peak period (Tp) in the SAO. The large share of wave
variability was explained by the first four modes, where a strong
correlation was found between Tp and swell (68%) and also that
with Hs (61%). The cross-correlation functions of the 1st and 2nd
PCs time series were calculated and compared to Southern Annular
Mode (SAM). The results have led us to conclude that the leading
potential mechanism that drives the short-scale variability of
ocean surface wave in the SAO is the extratropical cyclone amount
variability. It could be noticed that the first modes of U10 and
Hs were significantly related, as well as their second modes. The
spatial pattern of the EOF3 of U10 started appearing in the EOF3
of Hs, but became really similar to the fourth mode of the Hs,
what outpoint the known time lag of ocean surface response to the
atmospheric forcing. The EOF1 of swell has exhibited positive
anomalies in southeast of grid and lowering of them toward
northeast, showing that there is a correspondence between the
propagation directions of swell and the dominant directions of
storms. From spatial patterns were noticed contributions of swell
from Pacific, Indian and North Atlantic Oceans. The anomalies (+)
observed in the first and second Hs modes showed a contribution of
swell from the Indic Ocean modifying the wave climate in the SAO.
The application of cross-correlation function of PCs time series
has provided the information that one maximum oscillation happened
in each two day. We guess that this short and synoptic scale can
have some relation to the extratropical cyclone variability. A
clear seasonal fluctuation could be noted, particularly for the
summer months, but the period studied is much short for a deep
seasonal analyze. The negative tendency of SAM added with its also
negative correlation coefficient with all variables analyzed
indicate that the storms have shifted toward midlatitudes, and,
consequently, larger is the chance to occur swell events. In this
way, the results obtained here lead us to conclude that the
leading potential mechanism that drives the short-scale
variability of Hs and swell in the SAO is the extratropical
cyclone amount variability. The application of EOF and SVD methods
for obtaining leading modes of short-scale spatial temporal
variability of oceanic waves, apart from appearing pioneer in the
South Hemisphere, provided a better understanding of the ocean
waves behavior in the South Atlantic Ocean and the relationship to
local process, to other Oceans and to the high latitudes
process.",
conference-location = "Foz do Igua{\c{c}}u",
conference-year = "8-12 Aug. 2010",
language = "en",
targetfile = "AGU_Parise\&Farina.pdf",
urlaccessdate = "19 abr. 2024"
}