ALTA, the APERTIF Long Term Archive, hosts science data-products generated by the imaging and time-domain science teams for APERTIF. APERTIF is the upgrade of the Westerbork Synthesis Radio Telescope resulting in the transformation to a survey instrument in the radio domain. APERTIF science surveys start in July 2019. The APERTIF science teams will generate data releases on a regular basis, the first of which is to be based on the Science Verification Campaign (SVC) that has been performed in preparation for the scientific surveys in Spring 2019. SVC data is planned to be released September 2019, resulting in first public use of ALTA. The ALTA system is designed to host a twenty petabyte data archive and integrates a tape-based scalable data storage, a 1.7 petabyte disk based online storage component, a database, and a web-based user portal providing data discovery and -retrieval functionality. The online storage component provides low latency access to science data products and a cache for the tape-backed data in the archive. The LTA storage services build on iRODS providing rule-based data management in a tiered distributed storage system. The database schema supports registration of full data provenance of archived products and is compliant with VO standards. Data products of all levels in the science analysis workflow can be stored, linked, and made available for discovery and retrieval through the user interface. In this contribution we will provide details of the ALTA system and share experiences of the first public data release.
