2023 International Geophysical Calendar (FINAL)

Cooperative programs pertaining to solar activity and the Earth's environment

Go to the Google Calendar.


The International Geophysical Calendar contains information about:

and recommended scientific programs for

EXPLANATIONS

This Calendar continues the series begun for the IGY years 1957-58, and is issued annually to recommend dates for solar and geophysical observations, which cannot be carried out continuously. Thus, the amount of observational data in existence tends to be larger on Calendar days. The recommendations on data reduction and especially the flow of data to World Data Centers (WDCs) in many instances emphasize Calendar days. The Calendar is prepared by the International Space Environment Service (ISES) with the advice of spokesmen for the various scientific disciplines.

The Calendar provides links to many international programs, giving an opportunity for scientists to become involved with data monitoring and research efforts. International scientists are encouraged to contact key people and to join the worldwide community effort to understand the Sun-Earth environment.

The definitions of the designated days remain as described on previous Calendars. Universal Time (UT) is the standard time for all world days. Regular Geophysical Days (RGD) are each Wednesday. Regular World Days (RWD) are three consecutive days each month (always Tuesday, Wednesday and Thursday). Priority Regular World Days (PRWD) are the RWD which fall on Wednesdays. World Geophysical Intervals (WGI) are 14 consecutive days in each season, beginning on Monday of the selected month, and normally shift from year to year. In 2021 the WGI are February, May, August, and November. Quarterly World Days (QWD) are one day each quarter and are the PRWD which fall in the WGI.

2023 Solar Eclipses:

  1. 20 April 2023, hybrid solar eclipse. Eclipse shadow extends from part of Antarctica and off the coast of Madagascar and ends in the Pacific Ocean, past Australia. As a hybrid solar eclipse, it starts out as annular before it changes to total and then back to annular before the path ends. The total eclipse can be seen from Exmouth in Western Australia at 11:30 Australian Time, with the totality lasting just under one minute. Partial phases can be observed from Australia, various islands in South East Asia and Oceania, and the Pacific Ocean. Perth, Australia, experiences a partial eclipse for a magnitude of 76% for almost hours between 10am-1pm AWST. Past that, Ende in Indonesia experiences 90% magnitude throughout late morning into earlier afternoon. In Port Moresby, Papua New Guinea, early afternoon has 67% magnitude and the eclipse continues northward before ending past Samoa.
  2. 14 October 2023, annular solar eclipse. Partial eclipse is visible from northeastern Canada and Alaska, moves over the rest of North America, through Central American before ending in South America, off the coast of Brazil and just along the western African coast. The annular eclipse can be seen thoughout Southern United Stats, Belize, Columbia, and Brazil. San Antonio in Texas, USA experiences 90% coverage of the sun through out its morning into early afternoon. Partial coverage can be seen in Vancouver, Canada in the morning with 75% coverage, Mexico City, Mexico in late morning for 70% coverage, and Iquitos, Peru, in the afternoon for 80% coverage. The partial eclipse ends over the horizon in Aracaju, Brazil in late afternoon at 78% coverage and only 6% in Bissau, Guinea-Bissau off the coast of Africa in the local evening.

See http://www.eclipses.info from the International Astronomical Union's Working Group on Solar Eclipses for links. Information assembled by Jay M. Pasachoff, Williams College (Williamstown, MA); Visitor at Carnegie Observatories (Pasadena, CA); Chair, International Astronomical Union's Working Group on Eclipses. Thanks to Fred Espenak (Arizona) (http://EclipseWise.com) and Xavier Jubier (Paris) (http://xjubier.free.fr/en/) for their data and maps; see also Michael Zeiler's http://eclipse-maps.com for maps and Jay Anderson's http://eclipsophile.com for weather and cloudiness discussions. Espenak's Thousand Year Canon of Solar Eclipses: 1501 to 2500 is available from www.astropixels.com/pubs, and is the successor to earlier Canons and the NASA website that he ran. It and other work of Espenak, much of it formerly on the NASA website, is now available at http://EclipseWise.com.

All 21st-century eclipses are shown on a solar-eclipse globe from Michael Zeiler and Sky & Telescope . It includes 68 total solar eclipses and 7 annular-total (hybrid) solar eclipses.

2023 Meteor Showers

(Selected from data compiled by Jürgen Rendtel for the International Meteor Organization Shower Calendar):

  1. Annual meteor showers liable to have geophysical effects:
  2. Dates Peak Time (UT in 2023) Name
    December 28-January 12 January 04, 3:40 Quadrantids (QUA)
    January 31-February 20 February 08 α-Centaurids (ACE)
    April 14-30 April 23, 1:00 Lyrids (LYR)
    April 19-May 28 May 061 η-Aquariids (ETA)
    May 14-June 24 June 07 Daytime Arietids (ARI)2
    May 20-July 05 June 10 Daytime ζ-Perseids (ZPE)
    June 05-July 17 June 28 Daytime β-Taurids (BTA)
    July 12-August 23 July 30 Southern δ-Aquariids (SDA)
    July 17-August 24 August 13, 7:00-14:00 Perseids (PER)
    September 09-October 09 September 27 Daytime Sextantids (DSX)
    October 02-November 07 October 21 Orionids (ORI)
    November 06-November 30 November 18, 5:00 Leonids (LEO)
    December 01-December 15 December 073 Puppid-Velids (PUP)
    December 04-December 20 December 14, 19:00 Geminids (GEM)
    December 17-December 26 December 23, 4:00 Ursids (URS)

    1Observations of the maximum will be badly affected by the full moon on May 5

    2Daytime Arietids and Daytime ζ-Perseids tend to blend into one another, producing a strong radio signature for several days in early to mid June. The shower maxima dates are not well established.

    3Reference date for the radiant only, not necessarily a true maximum.

  3. Annual meteor showers which may have geophysical effects:
  4. Dates Peak Time (UT in 2022) Name
    April 15-April 28 April 24, 06:00 π-Puppids (PPU)
    June 22-July 02 June 27, 22:00 June Boötids (JBO)
    August 28-September 05 September 01 α-Aurigids (AUR)1
    September 05-September 21 September 09, 23:00 September ε-Perseids (SPE)
    October 06-October 10 October 09, 07:00 Draconids (DRA)
    November 15-November 25 November 22 α-Monocerotids (AMO)

    1This northern-hemisphere shower has produced short, unexpected, outbursts at times, with peak ZHRs of ∼ 30−50 recorded in 1935, 1986, 1994 and 2019. Other events may have been missed because the shower has not been monitored regularly.

  5. Additional activity of note: Dates (based on UT in year 2023) are:

Meteor Shower Websites:

Meteor Shower References:

Real Time Space Weather and Earth Effects

The occurrence of unusual solar or geophysical conditions is announced or forecast by ISES through various types of geophysical "Alerts" (which are widely distributed via the internet on a current schedule). Stratospheric warmings (STRATWARM) were also designated for many years. The meteorological telecommunications network coordinated by the World Meteorological Organization (WMO) carries these worldwide Alerts once daily soon after 0400 UT. For definitions of Alerts see ISES URSIgram Codes.

RECOMMENDED SCIENTIFIC PROGRAMS (FINAL EDITION)

(The following material was reviewed in 2021 by the ISES committee with the advice of representatives from the various scientific disciplines and programs represented as suitable for coordinated geophysical programs in 2022.)

Airglow and Aurora Phenomena.

Airglow and auroral observatories operate with their full capacity around the New Moon periods. However, for progress in understanding the mechanism of many phenomena, such as low latitude aurora, the coordinated use of all available techniques, optical and radio, from the ground and in space is required. Thus, for the airglow and aurora 7-day periods on the Calendar, ionosonde, incoherent scatter, special satellite or balloon observations, etc., are especially encouraged. Periods of approximately one weeks' duration centered on the New Moon are proposed for high resolution of ionospheric, auroral and magnetospheric observations at high latitudes during northern winter.

Atmospheric Electricity.

Non-continuous measurements and data reduction for continuous measurements of atmospheric electric current density, field, conductivities, space charges, ion number densities, ionosphere potentials, condensation nuclei, etc.; both at ground as well as with radiosondes, aircraft, rockets; should be done with first priority on the RGD each Wednesday, beginning on 05 January 2022 at 0000 UT, 12 January at 0600 UT, 19 January at 1200 UT, 26 January at 1800 UT, etc. (beginning hour shifts six hours each week, but is always on Wednesday). Minimum program is at the same time on PRWD beginning with 26 January at 1200 UT. Data reduction for continuous measurements should be extended, if possible, to cover at least the full RGD including, in addition, at least 6 hours prior to indicated beginning time. Measurements prohibited by bad weather should be done 24 hours later. Results on sferics and ELF are wanted with first priority for the same hours, short-period measurements centered around minutes 35-50 of the hours indicated. Priority Weeks are the weeks that contain a PRWD; minimum priority weeks are the ones with a QWD. The World Data Centre for Atmospheric Electricity, 7 Karbysheva, St. Petersburg 194018, USSR, is the collection point for data and information on measurements.

Geomagnetic Phenomena.

It has always been a leading principle for geomagnetic observatories that operations should be as continuous as possible and the great majority of stations undertake the same program without regard to the Calendar.

Stations equipped for making magnetic observations, but which cannot carry out such observations and reductions on a continuous schedule are encouraged to carry out such work at least on RWD (and during times of MAGSTORM Alert).

Ionospheric Phenomena.

Special attention is continuing on particular events that cannot be forecast in advance with reasonable certainty. The importance of obtaining full observational coverage is therefore stressed even if it is only possible to analyze the detailed data for the chosen events. In the case of vertical incidence sounding, the need to obtain quarter-hourly ionograms at as many stations as possible is particularly stressed and takes priority over recommendation (a) below when both are not practical.

For the vertical incidence (VI) sounding program, the summary recommendations are:

  1. All stations should make soundings on the hour and every quarter hour;
  2. On RWDs, ionogram soundings should be made at least every quarter hour and preferably every five minutes or more frequently, particularly at high latitudes;
  3. All stations are encouraged to make f-plots on RWDs; f-plots should be made for high latitude stations, and for so-called "representative" stations at lower latitudes for all days (i.e., including RWDs and WGIs) (Continuous records of ionospheric parameters are acceptable in place of f-plots at temperate and low latitude stations);
  4. Copies of all ionogram scaled parameters, in digital form if possible, be sent to WDCs;
  5. Stations in the eclipse zone and its conjugate area should take continuous observations on solar eclipse days and special observations on adjacent days. See also recommendations under Airglow and Aurora Phenomena.

For the incoherent scatter observation program, every effort should be made to obtain measurements at least on the Incoherent Scatter Coordinated Observation Days, and intensive series should be attempted whenever possible in WGIs, on Dark Moon Geophysical Days (DMGD) or the Airglow and Aurora Periods. The need for collateral VI observations with not more than quarter-hourly spacing at least during all observation periods is stressed.

Special programs are described by the 2022 World Day Schedule which lists Incoherent Scatter coordinated observation days tabulated below. Data collection on such days starts by 1300 UT on the indicated start date and ends no later than 2000 UT the ending day (i.e., a 1 day experiment runs for at least 31 hours).

Start Date Length Experiment
Alert window from January 5-February 15 7 Stratwarm, Descending Layers1
March 19 7 Equinox Transition, CONGSS-232
June 19 5 Descending Layers
September 21 5 Descending Layers, CONGSS-233

1The experiments want broadly similar measurements therefore we can combine them. All will have a reduction in time. Operators have made it clear that a December start is problematic. If no Stratwarm alert occurs 5 days will run at the end of the period. Period = 5 January-15 February.

2CONGS-23 and Equinox transition can be combined since they are observing the same period and want similar measurements

3CONGS-23 and Descending layers can be combined since they want similar observations. However, this requires Descending layers to occur in late September rather than October.