Solar tiling and tracking extraction service using the VSO API as the backend

1. Solar tiling and tracking extraction service using the VSO API as the backend http://virtualsolar.org F. I. Suárez-Solá1, E. González-Suárez1, I. González-Hernández1, A.R. Davey2,J. Hourclé3, VSO Team 1National Solar Observatory, Tucson AZ – 2Harvard-Smithsonian Center for Astrophysics, Cambridge MA – 3NASA/GSFC, Greenbelt In solar research it is often necessary to isolate areas of the Sun for further studies.  Most scientists develop their own set of tools to extract the areas in which they are interested and build temporal series that include selected solar phenomena, however the overwhelming amount of available solar data, especially since the launch of SDO (Solar Dynamics Observatory), makes it difficult for researchers to access selected sets of data without downloading very large images.   With the help of one of the modules of the GONG (Global Oscillation Network Group) "ring-diagram'"pipeline and the VSO (Virtual Solar Observatory) API (Application Programming Interface), we built an asynchronous Solar data cube extraction service for GONG, SOLIS (Synoptic Optical Long-term Investigations of the Sun) and SDO data.  The service has a simple ad-hoc HTML front end for researchers to access it. The data cube extraction service takes as input as set of solar coordinates, a period of time, the size of the requested area, the spatial resolution needed, projection to use (cylindrical or postel) and the images to work on.  The service then tracks the sun and corrects for standard solar rotation effects.  The extracted files are saved to a staging area and the user is notified via email or a SOAP callback function that the processed images are available for download. Technical Overview Flare studies AIA 171 Å AIA 193 Å AIA 4500 Å 10-Mar-2011 20:00:08 Eruptive solar events such us solar flares are a mayor focus in solar studies. They are typically investigated at particular wavelengths due to data availability. The cube extraction service will provide simultaneous observations from different instruments and wavelengths seamlessly, given the solar scientist the opportunity to see a more complete picture. HMI Continuum VSO The GUI is in a simplified version of the VSO GUI plus the parameters the cube extraction needs: Cadence: Cube region: Latitude and longitude Patch size: In degrees Resolution: in pixels Projection type: Postel or Cylindrical. SOAP Interface The GUI can be as flexible as one need it to be. Thanks to the very versatile VSO SOAP interface. The GUI forms the initial query to the VSO (Query SOAP CALL), which returns meta-pointers to data. The second VSO call the VSO GetData gets the pointers to the actual data. The data gets downloaded with a simple wget and stored locally on disk. VSO GetData The fits headers need to be normalized to meet the cube extraction input requirements. HMI magnetogram GONG h-alpha Storage system The fits headers might get new keys and in same cases the data might need special pre-processing. Local helioseismology studies GONG Dopplergram HMI Dopplergram On the importance on best practices for FITS headers please see Joe Hourclé poster: 201.28 "Recommendation for FITS Headers” Local helioseismology infers subsurface properties of the Sun by studying the behavior of waves in localized areas. In typical analysis techniques, areas of different sizes are isolated from full disk Dopplergrams, re-projected, tracked for a period of time and analyzed independently. Helioseismology research focused on active region dynamics, for example, can clearly benefit from a service that provides data cubes. Fits header standardizer The cube extraction can reproject the data in postel or cylindrical projections. It can also work and extract multiple regions. In general the speed of reprojection and extraction proportional to the patch size and resolution chosen. In general is very CPU intensive. GONG Dopplergram Cube reprojection and extraction Data acknowledgments: This work utilizes HMI and AIA data supplied courtesy of the SDO/HMI and SDO/AIA consortia. SDO is the first mission to be launched for NASA's Living With a Star (LWS) Program and h-alpha data obtained by the NISP (NSO Integrated Synoptic Program) /GONG (Global Oscillation Network Group), managed by the National Solar Observatory, which is operated by AURA, Inc. under a cooperative agreement with the National Science Foundation. FTP Area HMI magnetogram HMI Dopplergram The data gets placed in an FTP area and the user gets notified