INTERMAGNET Technical Reference Manual

version : 30c8900

This document has been prepared by the INTERMAGNET Operations Committee and Executive Council. Every effort has been made to ensure that the information is accurate and current. The document is distributed in the hope that it will be a useful reference not only for those participating formally in INTERMAGNET, but also for the greater geomagnetic community.

ACKNOWLEDGMENTS

We gratefully acknowledge the many significant contributions and comments provided by our colleagues.

Cite as:

St-Louis, B. (Ed.), INTERMAGNET Operations Committee and Executive Council, 2024, INTERMAGNET Technical Reference Manual, Version 30c8900

The INTERMAGNET Office :

INTERMAGNET

c/o British Geological Survey

The Lyell Centre

Research Avenue South

Edinburgh EH14 4AP

UK

QUICK REFERENCES

• INTERMAGNET web site

  
  

  https://www.intermagnet.org/

  
  
• GIN internet addresses

  
  

  Ottawa: charles.blais@canada.ca

  Paris: par_gin@ipgp.fr

  Golden: aclaycomb@usgs.gov

  Edinburgh: e_gin@mail.nmh.ac.uk

  Kyoto: kyoto-gin@swdcdb.kugi.kyoto-u.ac.jp

  
  
• INTERMAGNET PHYSICAL MEDIA (IPM) distribution office

  
  

  INTERMAGNET Physical Media distribution office

  Observatoire Magnétique National

  Carrefour des 8 routes

  45340 Chambon la Forêt

  FRANCE

  TEL: 33 (0) 2-38-33-95-01

  INTERNET: intermagnet@ipgp.fr

  
  

• General inquiries

  
  

  Andrew Lewis

  INTERMAGNET Operations Committee

  c/o Geoscience Australia

  Cnr Jerrabomberra Avenue and Hindmarsh Drive Symonston ACT

  GPO Box 378

  Canberra ACT 2601

  Australia

  TEL: +61 2 6249 9764

  FAX: +61 2 6249 9999

  INTERNET: andrew.lewis@ga.gov.au

  
  

• INTERMAGNET membership application

  
  

  Information on how to apply for membership can be found in Chapter 8. The application form can be downloaded from https://intermagnet.org/membership.html

  
  

  More information can be obtained from the INTERMAGNET Observatories Subcommittee chair:

  
  

  Chris Turbitt

  INTERMAGNET

  c/o British Geological Survey

  The Lyell Centre

  Research Avenue South

  Edinburgh EH14 4AP

  United Kingdom

  TEL: 44-131-667-1000

  FAX: 44-131-667-1877

  INTERNET: c.turbitt@bgs.ac.uk

  
  

Table of Contents

• 1. INTERMAGNET
  • 1.1. Introduction
  • 1.2. INTERMAGNET Vision, Mission and Objectives
  • 1.3. History and Status of INTERMAGNET
  • 1.4. The INTERMAGNET Principles and Conditions
  • 1.5. Participation
  • 1.6. Products
  • 1.7. Conditions of Use
  • 1.8. INTERMAGNET Management
• 2. INTERMAGNET Magnetic Observatories - One Minute IMOs
  • 2.1. Description
  • 2.2. Environment/Location
  • 2.3. Instrumentation/Specifications
    • 2.3.1. Definitive Data
    • 2.3.2. Absolute Measurements
    • 2.3.3. Vector Magnetometer
    • 2.3.4. Scalar Magnetometer
    • 2.3.5. Clock Timekeeping
    • 2.3.6. Recorder
    • 2.3.7. Transmission
    • 2.3.8. Other
    • 2.3.9. Proton Gyromagnetic Ratio
  • 2.4. Data Sampling and Filtering
  • 2.5. Missing Data
  • 2.6. Data Quality Control
• 3. INTERMAGNET Magnetic Observatories - One Second IMOs
  • 3.1. Description
  • 3.2. Environment/Location
  • 3.3. Instrumentation/Specifications
    • 3.3.1. Definitive Data
    • 3.3.2. Absolute Measurements
    • 3.3.3. Vector Magnetometer
      • 3.3.3.1. General Specifications
      • 3.3.3.2. Pass Band Specifications [DC to 8mHz (120s)]
      • 3.3.3.3. Pass Band Specifications [8mHz (120s) to 0.2Hz]
      • 3.3.3.4. Stop Band Specifications [0.5 Hz]
    • 3.3.4. Scalar Magnetometer
    • 3.3.5. Auxiliary Measurements
    • 3.3.6. Recorder
    • 3.3.7. Transmission
    • 3.3.8. Other
  • 3.4. Data Sampling and Filtering
  • 3.5. Missing Data
  • 3.6. Data Quality Control
• 4. Absolute Measurements
  • 4.1. Definition and Frequency
  • 4.2. Instrumentation/Specifications
  • 4.3. Measurement Method
  • 4.4. Data Quality Control
  • 4.5. Observatory Operations
  • 4.6. Variometer Operations
  • 4.7. Baseline Calculation
  • 4.8. Calculation of the Difference Between F Pillar and Absolute Pillar
  • 4.9. Training
  • 4.10. References
• 5. Processing Data
  • 5.1. Introduction
  • 5.2. Data Quality Control & Processing Tasks
    • 5.2.1. Daily Data Quality Tasks
    • 5.2.2. Weekly Data Quality Tasks
    • 5.2.3. Monthly Data Quality Tasks
    • 5.2.4. Annual Data Quality Tasks
    • 5.2.5. Despiking and Removal of Artificially Disturbed Data
    • 5.2.6. Absolute Quality Control
  • 5.3. Computation of Baseline Values
  • 5.4. Baseline Adoption
  • 5.5. The Computation of Total Field Differences
  • 5.6. Producing Quasi-Definitive Data
  • 5.7. Summary
• 6. Submitting Data
  • 6.1. Introduction
    • 6.1.1. Data Formats
      • 6.1.1.1. IMFV1.23 GIN Dissemination Format
      • 6.1.1.2. IMFV2.83 Satellite Transmission Format
      • 6.1.1.3. IAGA-2002
      • 6.1.1.4. INTERMAGNET Archive Format
      • 6.1.1.5. ImagCDF
      • 6.1.1.6. IYF INTERMAGNET Year-Mean File
      • 6.1.1.7. IBF INTERMAGNET Baseline File
    • 6.1.2. Data Types
    • 6.1.3. Geomagnetic Components (or Elements)
    • 6.1.4. Near Real-Time Preliminary Data
    • 6.1.5. Geomagnetic Information Nodes
      • 6.1.5.1. GIN Manager Addresses
      • 6.1.5.2. GIN Email Addresses
      • 6.1.5.3. INTERMAGNET GIN Types
  • 6.2. Submission of Preliminary Data
    • 6.2.1. Update Frequencies and Formats for Preliminary Data
    • 6.2.2. Types of Preliminary Data
    • 6.2.3. Submission via WEB Service
    • 6.2.4. Submission via Email
    • 6.2.5. Satellite Transmission
      • 6.2.5.1. Geostationary Satellites
      • 6.2.5.2. METEOSAT
      • 6.2.5.3. GOES
      • 6.2.5.4. Transmission Access
      • 6.2.5.5. Satellite Operators
      • 6.2.5.6. Satellite Services
    • 6.2.6. Transferring Data from GINs to WEB Site
    • 6.2.7. How to Check if Your Data Has Been Received
    • 6.2.8. Common Problems with Data Transmission
    • 6.2.9. Data Publication Delays
  • 6.3. Submission of Quasi-Definitive Data
    • 6.3.1. Update Frequencies and Formats for Preliminary Data
    • 6.3.2. Submission via WEB Service
    • 6.3.3. Submission via Email
    • 6.3.4. How to Check if Your Data Has Been Received
    • 6.3.5. References
  • 6.4. Definitive 1-Minute Data
    • 6.4.1. Checking Procedure
    • 6.4.2. Obtaining the Checking Software
    • 6.4.3. Data Encoding for Publication
      • 6.4.3.1. General Features
      • 6.4.3.2. IAF INTERMAGNET Archive Format
        • 6.4.3.2.1. IAFV2.11 (2014 and after)
      • 6.4.3.3. INTERMAGNET Reference Data Set and Physical Media Directory Structure
      • 6.4.3.4. INTERMAGNET Reference Data Set and Physical Media Software
  • 6.5. Definitive Data Calculation Based on Most Common Orientations
  • 6.6. Standards for Calculating Hourly, Daily and Annual Means
    • 6.6.1. Hourly Mean Values
    • 6.6.2. Daily Mean Values
    • 6.6.3. Annual Mean Values
    • 6.6.4. Rule for Missing 1-minute Values
  • 6.7. Definitive 1-Second Data
• 7. Using INTERMAGNET Data
  • 7.1. INTERMAGNET WEB Site
    • 7.1.1. WEB Site Address
    • 7.1.2. Online Technical Reference Manual
    • 7.1.3. Downloading Data
      • 7.1.3.1. Downloading Data Using DOIs
      • 7.1.3.2. Downloading Data Using the WEB Interface
    • 7.1.4. Geomagnetic Activity
  • 7.2. Data Viewer
  • 7.3. Condition Use
    • 7.3.1. Acknowledgment of Data from Observatories Participating in INTERMAGNET
• 8. How to Apply for Membership
  • 8.1. Application
  • 8.2. INTERMAGNET Participation Policy
    • 8.2.1. Observatory Application to the INTERMAGNET Network
    • 8.2.2. Ongoing Participation in the INTERMAGNET Network
    • 8.2.3. Withdrawal of INTERMAGNET Status

• INTERMAGNET Terminology
• Observatories Participating in INTERMAGNET
• Archive Data Formats
  • INTERMAGNET Archive Format : IAF
    • IAFV2.11 Binary Data Structure Format-32 Bit Words
    • IAFV2.10 Binary Data Structure Format-32 Bit Words
      • IAFV2.10 (2010 to 2013)
    • IAFV2.00 Binary Data Structure Format-32 Bit Words
      • IAFV2.00 (2009)
    • IAFV1.10 Binary Data Structure Format-32 Bit Words
      • IAFV1.10 (2008)
    • IAFV1.00 Binary Data Structure Format-32 Bit Words
      • IAFV1.00 (2007 and before)
  • INTERMAGNET Physical Media Directory Structure
    • Structure of the USB (2014)
    • Structure of (2011) DVD
    • Structure of first (1991) CD-ROM
    • INTERMAGNET Physical Media Directory Structure
    • List of Changes to the Structure since the first (1991) CD-ROM
  • INTERMAGNET Format for Yearmean File : IYF V1.02
    • Description of the Header Block
    • Description of the Footer
    • Sample of a Yearmean File
    • Sample of Missing Values
  • INTERMAGNET CD-ROM Software
• Contacts
  • INTERMAGNET Executive Council Addresses
  • INTERMAGNET Operations Committee Addresses
• Data Formats
  • INTERMAGNET Satellite Transmission Format : IMFV2.83
    • IMFV2.83 Header Encoding
    • IMFV2.83 Data Value Encoding
  • Satellite Coding Examples
    • Coding Example for Goes Satellite
    • Coding Example for Meteosat Satellite
    • Coding Example for GMS Satellite
    • Time Framing for GMS
      • Base-44 Coding for GMS
  • INTERMAGNET Gin Dissemination Format for Minute Values : IMFV
    • IMFV1.23
      • Description of the Header Block (64 characters including CrLf)
      • Description of Data Space (64 characters per line including CrLf)
    • IMFV1.22
      • Description of the Header Block (64 characters including CrLf)
      • Description of Data Space (64 characters per line including CrLf)
  • INTERMAGNET Baseline Format : IBF
    • IBFV2.00 (2009 and after)
    • IBFV1.20 (2008 and before)
  • IAGA2002 INTERMAGNET Exchange Format (Spreadsheet compatible)
    • The 12 Mandatory File Header Records
    • The Optional Comment Header Records
    • The Mandatory Data Header Record
    • The Data Records
    • Recommended File Name Procedure
    • Sample of IAGA-2002 Format July 2003 Revision
      • Sample Data Header and Data Record for 1-minute Values
      • Sample Data Header and Data Record for Hourly Values
      • Sample Data Header and Data Record for Monthly Values
      • Sample Data Header and Data Record for 1-second Values
      • Sample Data Header and Data Record for 5-Millisecond Values
  • IMAGCDFV1.2 INTERMAGNET Exchange Format
    • Design Details and CDF Concepts
      • General Design Details
      • Data Types Used for Variables and Attributes
        • Real Numbers
        • Dates / Times
        • Strings
      • Compression
    • Where to Obtain the CDF Software
    • ImagCDF Data
    • ImagCDF Global Attributes
      • Attributes that Describe the Data Format
      • Attributes that Uniquely Identify the Data
      • Attributes that Describe the Observatory
      • Attributes that Relate to Data Standards and Quality
      • Attributes that Relate to Publication of the Data
      • Valid Codes for Elements Recorded
      • Relevant Data Standards
    • ImagCDF Variable Attributes
    • ImagCDF File Names
      • ISO 8601 Duration Strings for Common Geomagnetic Sample Periods
      • Format of Date/Time Portion of Filename and Examples
    • Tools to Look at CDF Data
    • Example Data File
• Filter Coefficients
  • Filter Coefficients to Produce One Minute Values
  • Filter Coefficients to Produce One Second Values
• Acknowledgements