OVERVIEW

FOR MORE INFORMATION ON THE DEVELOPMENT OF ACE2 PLEASE SEE THE GENERATING ACE2 PAGE

The new ACE2 Dataset has been created by synergystically merging the SRTM dataset with Satellite Radar Altimetry within the region bounded by ±60N.
Over the areas lying outside the SRTMs latitude limits other sources have been used such as including GLOBE and the original ACE DEM, together with new matrices derived from reprocessing the ERS1 Geodetic Mission dataset with an enhanced retracking system, and the inclusion of data from other satellites.
The main altimetry dataset used in the generation of the dataset was the ERS-1 Geodetic mission; which due to its small across track spacing presents a uniquely dense spatial distribution of tracks of Radar Altimeter data over land surfaces. Data from ERS-2 and EnviSat Ku-band are included where appropriate. All of the altimeter data have been reprocessed using the Berry Expert System to retrack the waveforms.
Over 11,000,000,000 pixels have been adjusted from the SRTM dataset using this unique network of control arcs of altimeter derived height data. In addition to this over the rainforests extensive investigaion has shown that the Altimetry data are returning gound values where the SRTM signal is bouncing off somewhere within the canopy. Therefore over both the Amazon and the Congo the areas of rainforest have been completely replaced by an altimetry defined surface.

15 degree tile with bottom left pixel located at 15° South 75° West
In addition to warping the dataset and replacing where applicable with altimetry data an effort has been made to fill in the voids present within the SRTM dataset.

15 degree tile located at 60° North 75° East from GLOBE

15 degree tile located at 60° North 75° East from ACE2
Over areas where the base dataset is not available at the high resolution, 3" data have been supersampled from a newly created 30"matrix derived from multi-mission altimeter data combined with the best available ground truth. This has reduced the 'tiling' effect present in the ground truth datasets and brought the heights in line with the altimeter derived surface. Due to the orbits of the satellites used there was much more data available at higher latitudes and therefore higher warping factors have been permitted.

15 degree tile located at 60° North 75° East from GLOBE

15 degree tile located at 60° North 75° East from ACE2