Uma análise do campo de vento de superfície sobre o Oceano Atlântico Tropical e Sul usando dados do escaterômetro do ERS / An analysis of the surface wind field over tropical and South Atlantic Ocean using ERS scatterome.er data

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

Monthly mean and standard deviation values of surface winds of the Atlantic Ocean sector from 20o N to 40o S were generated from the ERS 1/2 scatterometer data. The data was obtained from IFREMER and covers the period from December 1991 to November 1998. The objective of this effort was the analysis of the spatial and temporal variability of the wind field for the region. The original data (wind direction and speed) were first converted into zonal and meridional components. Three day blocks of scatterometer data were used for the interpolation into a regular 1ox1o geographic grid.. A simple spatial interpolation that uses an iteration procedure with a correction of mean value of weighted errors was implemented. An evaluation of this algorithm was done comparing the interpolated results with winds measured by the buoys of the PIRATA project array and the wind data from the NCEP reanalysis. The rms differences of buoyscatterometer (P-S) and buoy-NCEP (P-N) wind magnitudes for 1998 were: 0;35W (PS= 1.13 ms-1; P-N=1.11 ms-1); 10S;10W (P-S=0.72 ms-1; P-N=1.83 ms-1) and 15N;38W (P-S=0.99 ms-1). The resulting wind fields describe the main features of Southeast and Northeast trades, with the ITCZ and semi-permanent high pressure system in the subtropics clearly detected. A meridional and seasonal migration of the center of the wind divergence in the South Equatorial Current region was observed in the scatterometer data. This could imply in a seasonal migration of the Brazil Current formation region. The annual harmonic is the strongest signal present in the wind data in the tropics; the regions with highest annual harmonic are associated with the maximum seasonal meridional migration of the ITCZ.

ASSUNTO(S)

climatologia. wind measurement buoys medição de vento buoys interpolation oceanografia climatology interpolação oceano atlântico

ACESSO AO ARTIGO

Documentos Relacionados