LIMA, E. A.; http://lattes.cnpq.br/6245822021636784; LIMA, Edivania de Araújo.
Résumé:
We analyzed the behavior of 311 Upper-Tropospheric Cyclonic Vortex
(UTCV) observed from january 1980 to december 2009, the region Northeast Brazil
(NEB) and adjacent South Atlantic. Was used data from Anomalies of Sea Surface
Temperature (SST) and Atlantic Oceans Pacific, the zonal (u) and meridional wind (v),
precipitation and Index of the Pacific Decadal Oscillation (IODP). From the
components of wind was calculated fields of relative vorticity, horizontal divergence
and the rotational and divergent components of the wind. The methodology consisted of
graphics and Principal Component Analysis (PCA), which allowed the verification of
the influence of SSTA in the occurrences of vortex. The results showed that during all
stages of VCAN was noticeable in 90% of cases the presence of the Bolivian high (BH)
and the anticyclonic vorticity from this center served a decisive maintenance of the
vortex. The preferred area for training was VCAN over the tropical Atlantic and under
normal conditions of the waters of Pacific (45.7% of events). In El Niño events, it was
noticed that the maximum VCAN occurred in regions where the SST Niño 1 +2 and
Niño 3.4 were more heated than the other regions of the Niños. Also concerning the
SSTA Pacific observed that when the IODP was positive and the El Niño was set were
recorded more VCAN than when the IODP was negative and had setting of La
Niña. Observing the rotational components and divergent wind, it was seen how these
two antagonistic components. The total pluviometric over NEB observed during the
events followed showed a great variability due to VCAN positioning. The PCA were
found two Principal Components (PC) that explained more than 50% of the variability
in the number of occurrences of VCAN according to the SSTA in the Atlantic and
Pacific. So it follows that the coupled ocean-atmosphere phenomena act in a
decisive VCAN dynamics of operating in northeast Brazil.
