SOI Data Sets


The browsers provided for selecting and exporting data from the SOI Data Storage and Distribution System (DSDS) need to make multiple queries to the database, depending on the particular datasets selected. It may take a while for the first search page to come up. This is not a problem with your internet connection! After that, the queries should be very fast until you make your final selection. Because most of the data archive is off-line, delays in actual data export can be up to a day or more, depending on the number of other pending requests. You will be informed by mail at the time your request is logged and again when it has been satisfied (or when it has failed for some reason).

Data Requests by Source

MDI Data

Available under conditions of the SOI data policy
Data derived from observations with the MDI instrument on SOHO in space.
Quick-look data derived from observations with the MDI instrument on SOHO in space as captured in near-real time from the Experiment Operations Facility (EOF).
Data derived from ground-based (test) observations with the MDI flight instrument.
Data derived from (test) observations with the MDI simulator.
Ancillary data from the SOHO spacecraft.
Quick-look data processed into Datasets corresponding to Campaign Sequences.

Imported Data

Available under conditions set by the original providers
Data from the upgraded Global Oscillations Network Group
Data from the Taiwan Oscillations Network
Mt Wilson MOF
Data from the Mt. Wilson 60-ft tower MOF instrument
Data derived from observations with the High-L Helioseismometer at Kitt Peak National Observatory
Data derived from observations with the High-L Helioseismometer operating at the South Pole
Data derived from observations with the Low-L instrument operated by the High Altitude Observatory
Simulations by Stein et al.
Simulations of solar hydrodynamic convection on supergranulation scales (48 Mm wide by 20 Mm deep)

Data Requests by Dataset Name

(if you know the exact SOI dataset names of the data you want)

Data Export Mechanisms

SOI data sets are available for export via the following mechanisms (click for explanations): Details of the required information for each export mechanism are provided in the export help page and on the export request forms themselves. Please note that many SOI datasets are large. Data storage requirements will be posted prior to final submission of your request. Check them!

Organization of SOI Data

Data sets contained in the Solar Oscillations Investigation (SOI) master database fall into three classes: This document is a brief overview of the entire contents of the SSSC database and is intended to help people get started in using the database. If you already know the name or attributes of the data series you are interested in, you may use a form provided to query the database directly. Be aware, however, that for historical reasons the dataset names available for user queries are not necessarily the same as the identifiers used internally in the database. (No description of the actual names in use in the database, including entitities other than scientific data, is available.)

Types of SSSC Data

Datasets are described in the SSSC database by Program, Processing Level and Series Name. A dataset described by a unique combination of these attributes (which consist of both a name and a sequence number) is a set of data files with a common organization together with any ancillary data files providing information about the whole collection. A dataset can physically occupy a single directory in a disc file system.

The SSSC Database

There are two database tables with information about SOI data. One, the dataset table, contains a line for each unique data series, i.e., each unique combination of Program name (and number), Level name (and number), and Series name (and number). The other provides information about a subset of these data series specified by some (not all) unique combinations of the names, ignoring different numbers. The second database contains the information needed by certain analysis modules to gather together multiple datasets from a data series, so entries in it are only required for those data series whose component sets are to be collected this way.

Observing Programs

Datasets are organized by program according to the instrumental origin of the original observational data. (When high-level analyzed data are based on datasets from multiple original programs, as for example with correlative or comparative studies, they will be cross-referenced from each program. So far there is no such case.) The program determines the data rights and, in the case of MDI data, the likely scientific utility of the derived datasets. Separate pages describe the organization of the datasets within each program, and the associated data rights.

Processing Levels

Data products are organized within the SOI project according to their level of processing as follows:
Instrumental data in their original format. As a rule, raw data are not suitable for direct analysis.
Raw data which have been converted to the format of a standard external storage protocol, usually FITS files. Level-0 data are preumed uncalibrated and stored in instrument units.
Level-1 (Calibrated)
Level-0 data which have been calibrated into physical units of the observable and time and location of the observation. Level-1 data are intended to be suitable for science data analysis and may be the final data product for some observing programs.
Collections of Level-1 data which have been assembled together with certain descriptive and ancillary data products (files) for use in SOI pipeline processing. Level-1.5 data products are stored as self-contained sets of files using standard storage protocols such as FITS and CDF, along with easily readable text information in straight ASCII formatted files.
Level-1 data which have been somehow reorganized by e.g. projection, smoothing, sampling, filtering, transforms, etc. Examples of Level-2 data products are spherical harmonic amplitude time series and frequencies of solar oscillation modes for various intervals of time.
When data are initially acquired at Level-2 (this is sometimes the case for imported data products) it may be necessary to assemble them for use in further SOI pipeline processing with the same kinds of descriptive and ancillary data products (files) as with the Level-1.5 data.
Descriptions of the different levels of processing as applied specifically to SOI data are given elsewhere (SOI Data Availability).

Level names take the following forms:

Data Series

There is no consistency to data series names except occasionally within individual programs and levels. Data within the mdi program at the raw level are named with reference to the originating telemetry stream; at the level-0 level they are named by the relevant Data Product Code (DPC), a hexadecimal representation of a 32-bit pattern. (A Data Product Decoder is available here for interpreting the meaning of individual DPC's.) Series names at level-1 and higher may or may not be more meaningful. The main data selection page for each program should contain a description of the associated series names.

Tables Connecting Lev0,1 To Lev1.5

Oracle Forms for Querying the SOI Database

Page last revised Thursday, 14-Sep-2006 16:00:35 PDT
Please address comments and questions to Rick Bogart, SOI Data Scientist

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