Version: 1 Gridded 18-year average height-change rate for Antarctic ice shelves. The complete description of processing steps is described by Paolo et al. (2016). Rates [m/year] were derived from a polynomial fit to 18 years (1994-2012) of continuous satellite radar-altimeter measurements of changes in ice-shelf surface height (European Space Agency (ESA) ERS-1, ERS-2 and Envisat missions). The rates have been corrected for for ocean tides, atmospheric pressure (inverse barometer), regional sea-level trends, and surface scattering variation. The spatial field has been filtered and gap filled using a Gaussian kernel (with standard deviation of 1-pixel). Values are only available for ice-shelf areas north of the maximum latitude (-81.5 degrees) of the altimeter satellites. Error bars [m/year] in the rates are two standard errors (95% confidence intervals) derived from 500 bootstrap samples. The dataset is a rectangular grid (480 points in x, 80 points in y) with x- and y-axes being longitude and latitude, respectively. Longitude/latitude coordinates refer to the center of the grid cells. The grid has a resolution of lon x lat: 0.75 x 0.25 deg (~27 km at latitude -71). Files are (two options: HDF5 and ASCII): ice_shelf_dhdt_v1.h5 # Gridded product in HDF5 format ice_shelf_dhdt_v1.txt # Grid-cell values in ASCII format ice_shelf_dhdt_v1.png # Figure with grid domain Data are (grids in HDF5 or columns in ASCII): lon # x-coordinate [degrees east; range 0/360] lat # y-coordinate [degrees north; range -82/-62] dhdt # Gaussian-filtered height-change rate [m/year] error # Height-change rate two standard error [m/year] Notes: Due to the wide radar altimeter (pulse-limited) footprint (~3-5 km), there is limited coverage near the grounding lines. This can potentially underestimate changes near some of the rapidly-changing grounding lines (e.g. Pine Island); see references for detailed information. References: Paolo F.S, H.A. Fricker, L. Padman, Constructing improved decadal records of Antarctic ice-shelf height change from multiple satellite radar altimeters, Remote Sensing of Environment, vol.177, pp.192-205 (2016). doi:10.1016/j.rse.2016.01.026 Paolo F.S., H.A. Fricker, L. Padman, Volume loss from Antarctic ice shelves is accelerating, Science, vol.348, pp.327-331 (2015). doi:10.1126/science.aaa0940 Fernando Paolo Jan 26, 2017