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Detecting the movement of oceanic fronts using registered Tiros‐N imagery
Author(s) -
Clark J. R.,
LaViolette P. E.
Publication year - 1981
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl008i003p00229
Subject(s) - compositing , remote sensing , geology , geodesy , pixel , position (finance) , data set , standard deviation , movement (music) , landmark , front (military) , computer science , data archive , image (mathematics) , artificial intelligence , database , mathematics , physics , statistics , oceanography , finance , acoustics , economics
An examination of TIROS‐N AVHRR data distributed by NOAA Environmental Data Information Service (EDIS) shows that with these data one has greatly improved positioning capability in comparison with data gathered by earlier NOAA satellites. In four of five distinct TIROS‐N data sets, involving earth scenes approximately 500 km square, we obtained a mean positioning error of 3.7 km with a standard deviation of 1.7 km based on 32 landmark points. The fifth data set shows discrepancies apparently resulting from erroneous EDIS data coordinates, and accurate positioning of this specific scene could not be made. In general, TIROS‐N data can be reliably registered into geographic grids of various map projections by using two‐dimensional, third‐order polynomials. The resulting image projections can be used to monitor and to measure the movements of oceanic fronts accurately. Examples of such measurements are presented using data from the May 1979 phase of the Grand Banks Experiments. These examples include four consecutive days of registered TIROS‐N imagery that show detailed southeasterly movement of horizontal frontal waves traveling at an average speed of 70 cm/sec. The accurate registration also allows precise compositing of several days' imagery. A four‐day composite based on the highest daily temperature per pixel position shows that an oceanic front can often be monitored despite cloud conditions.