February 2019 Altimeter Corrected Elevations (ACE2), v2 (1994-2005) PURPOSE To provide satellite altimeter corrected digital elevation data for environmental, socioeconomic, climate and other related research, such as flood risk assessment, land deformations, landslide modelling, urban planning, and sea level rise impacts. DESCRIPTION The Altimeter Corrected Elevations, Version 2 (ACE2) data set, is the Global Digital Elevation Model (GDEM) created by using multi-mission Satellite Radar Altimetry with the Shuttle Radar Topography Mission (SRTM). It was created by synergistically merging the SRTM data set with Satellite Radar Altimetry within the region bounded by 60°N and 60°S. Over the areas lying outside the SRTM latitude limits, other sources have been used including Global Observations to Benefit the Environment (GLOBE) and the original Altimeter Corrected Elevations (ACE) Digital Elevation Model (DEM), together with new matrices derived from reprocessing the European Remote Sensing (ERS-1) Geodetic Mission data set with an enhanced re-tracking system, and the inclusion of data from other satellites. ACE2 was developed at resolutions of 3, 9 and 30 arc-seconds, and 5 arc-minutes. The data are distributed in little-endian format as 15 degree by 15 degree tiles, with the name referring to the southwestern edge of the southwestern most pixel. ACCESSING THE DATA The data may be downloaded at http://sedac.ciesin.columbia.edu/data/set/dedc-ace-v2/data-download DATA FORMAT This archive contains the data in little-endian format. The data files are compressed zipfiles. Downloaded files need to be uncompressed in a single folder using either WinZip (Windows file compression utility) or similar application. Users should expect an increase in the size of downloaded data after decompression. DATA VALUES Data values are in meters. SPATIAL EXTENT Global 3, 9 and 30 arc-seconds, and 5 arc-minutes. DISCLAIMER CIESIN follows procedures designed to ensure that data disseminated by CIESIN are of reasonable quality. If, despite these procedures, users encounter apparent errors or misstatements in the data, they should contact SEDAC User Services at ciesin.info@ciesin.columbia.edu. Neither CIESIN nor NASA verifies or guarantees the accuracy, reliability, or completeness of any data provided. CIESIN provides this data without warranty of any kind whatsoever, either expressed or implied. CIESIN shall not be liable for incidental, consequential, or special damages arising out of the use of any data provided by CIESIN. USE CONSTRAINTS Users are free to use, copy, distribute, transmit, and adapt the work for commercial and non-commercial purposes, without restriction, as long as clear attribution of the source is provided. RECOMMENDED CITATION(S) Data Set: Berry, P. A. M., R. Smith, and J. Benveniste. 2019. Altimeter Corrected Elevations, Version 2 (ACE2). Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC). https://doi.org/10.7927/H40G3H78. Accessed DAY MONTH YEAR. Scientific Publication: Berry, P. A. M., R. Smith, and J. Benveniste. 2010. ACE2: The New Global Digital Elevation Model. In: Merrltika, S. (eds) Gravity, Geoid and Earth Observation, International Association of Geodesy Symposia 135: 231-237. Berlin, Heidelberg: Springer. https://doi.org/10.1007/978-3-642-10634-7_30.