SRTM15V2.0

SRTM15+V2.0 represents the newest iteration of the SRTM+digital elevation model (DEM), constructed using our latest compilation of shipboard soundings and satellite-derived predicted depths. This follows from SRTM30_PLUS (Becker et al., 2009) and SRTM15_PLUS (V1; Olson et al., 2016), where the “plus” represents the addition of the ocean bathymetry, our principal contribution to the model. Motivation for this update stems from the improvement in both accuracy and resolution achievable by including a wealth of new data that has been acquired over the past few years, in addition to the inclusion of a previously underutilized global shipboard sounding compilation. Currently, there are three satellite altimeters in non-repeat orbits from which we source data, and these have collected a substantial volume of new data over the past ∼4 years; data from AltiKa, which operates using the Ka-band, are of particular importance due to its superior range precision (e.g., Smith, 2015; Zhang & Sandwell, 2017). In addition, the National Geospatial-Intelligence Agency has provided a global shipboard sounding data set, which uniquely fills ∼18.8 million grid cells at 15-arc sec resolution. These data are further bolstered by data from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and three regional-scale high-resolution multibeam surveys that together provide an additional ∼14.8 million soundings. Collectively, SRTM15+V2.0 incorporates >33.6 million new ship-constrained grid cells and greater than six cumulative years of altimetry measurements relative to SRTM15_PLUS (Olson et al., 2016). Onshore elevations are also updated and are greatly improved in the high and low latitudes, owing to the inclusions of the recently released ArcticDEM (Porter et al., 2018) and Reference Elevation Model of Antarctica (REMA; Howat et al., 2018) models, respectively. Reference: Tozer, B., Sandwell, D. T., Smith, W. H. F., Olson, C., Beale, J. R., & Wessel, P. (2019). Global bathymetry and topography at 15 arc seconds: SRTM15+ , Earth and Space Science, https://doi.org/10.1029/2019EA000658 .