Dataset: SeaWIFS Images
Deployment: 61TG_3052

This dataset contains images of the SOIREE bloom, as described in


Abraham, E.R., Law, C.S., Boyd, P.W., Lavender, S.J., Maldonado, M.T.,


and Bowie, A.R. (2000) Importance of stirring in the development of

an iron-fertilized bloom. Nature 407, 727-730.



The SeaWiFS data were provided by the NASA/DAAC GSFC and are copyright


of Orbital Imaging Corps and the NASA SeaWiFS project. The data were

processed at CCMS-PML by Samatha Lavender.



The images are in PNG format. Chlorophyll values can be extracted

from the imagery by applying the conversion equation:



log10(chl)=((Pixel value)*slope)+log10(intercept)



where slope = 0.015 and intercept = 0.01.



The images are in a non-standard Mercator projection and the following

formulae may be used to convert latitude/longitude (lat/lon) positions

to x/y pixel co-ordinates or vica-versa.



Given lat and lon

Calculate x position:

FractX = (lon - minlon) / (maxlon - minlon)

x = cols * FractX



Calculate y position:

Ymin=logn(tan(DEGTORAD*(45.0+(lat/2.0))))

Ymax=logn(tan(DEGTORAD*(45.0+(maxlat/2.0))))

y=(cols *(Ymax-Ymin))/(DEGTORAD*(maxlon-minlon))



Given x and y

Calculate Longitude:

Fractx=(x-1)/(cols-1)

lon=Fractx*(maxlon-minlon)+minlon



Calculate Latitude:

Ymax=logn(tan(DEGTORAD*(45.0+(maxlat/2.0))));

Ymin=Ymax-(y-1)*DEGTORAD*(maxlon-minlon)/(cols-1);

lat= 2*(atan(exp(Ymin))/DEGTORAD - 45);





Where rows = 431 cols = 445 minlon =137.0 maxlon = 145.0 maxlat = -59.001762

DEGTORAD - conversion from degrees to radians (PI/180.0)



Queries and permission to use the images should be addressed to

Edward Abraham (e.abraham@niwa.cri.nz)