A new global bathymetry map at 15 arcsecond resolution for resolving seafloor fabric: SRTM15_PLUS

Abstract:

Abyssal hills are the most common topographic features on the

Earth yet they are not well resolved in the currently available global

topography/bathymetry maps at 30 arcsecond resolution (e.g.,

SRTM30_PLUS and GEBCO_08). To provide an improved mapping

of the seafloor fabric globally, we have used available sounding data

along with an improved global marine gravity model to develop at grid

at 15 arcsecond resolution (~500 m). Land elevations are based on

the best available data from SRTM, ASTER digital elevation models

while the ice topography of Greenland and Antarctica is based on

CryoSat-2 and IceSat. Ocean bathymetry is based on bathymetric

predictions from the latest global gravity model from CryoSat-2 and

Jason-1 along with 494 million carefully edited depth soundings at

15 arcsecond resolution. Bathymetry of the Arctic seafloor is based

on the IBCAO grid with improved resolution in areas of multibeam

coverage. We have used the bathymetry grid along with the

improved gravity to construct a global map of abyssal hill amplitude

and orientations and compare the orientations with predictions

from seafloor age gradient analysis. Areas of disagreement reveal

propagating rifts, microplates, and tectonic reorganizations. This

SRTM15_PLUS provides the foundational bathymetry layer for

Google Earth and is freely available at our ftp site (topex.ucsd.edu).