Cooperative programs pertaining to solar activity and the Earth's environment
The International Geophysical Calendar contains information about:
and recommended scientific programs for
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 2024 the WGI are January, May, August, and November. Quarterly World Days (QWD) are one day each quarter and are the PRWD which fall in the WGI.
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.
(Selected from data compiled by Jürgen Rendtel for the International Meteor Organization Shower Calendar):
| Dates | Peak Time (UT in 2024) | Name |
|---|---|---|
| December 28-January 12 | January 04, 09:00 | Quadrantids (QUA) |
| January 31-February 20 | February 09 | α-Centaurids (ACE) |
| April 14-30 | April 22, 07:00 | Lyrids (LYR) |
| April 19-May 28 | May 05, 21:00 | η-Aquariids (ETA) |
| May 14-June 24 | June 07 | Daytime Arietids (ARI) |
| May 30-June 20 | June 09 | Daytime ζ-Perseids (ZPE) |
| June 15-July 05 | June 25 | Daytime β-Taurids (BTA) |
| July 12-August 23 | July 31 | Southern δ-Aquariids (SDA) |
| July 17-August 24 | August 12, 13-16 | Perseids (PER) |
| September 09-October 09 | September 27 | Daytime Sextantids (DSX) |
| October 02-November 07 | October 21 | Orionids (ORI) |
| November 06-November 30 | November 17, 04:00 | Leonids (LEO) |
| December 01-December 15 | December 071 | Puppid-Velids (PUP) |
| December 04-December 20 | December 14, 01:00 | Geminids (GEM) |
| December 17-December 26 | December 22, 10:00 | Ursids (URS) |
1Reference date for the radiant only, not necessarily a true maximum.
| Dates | Peak Time (UT in 2024) | Name |
|---|---|---|
| April 15-April 28 | April 23 | π-Puppids (PPU) |
| June 22-July 02 | June 27, 22:00 | June Boötids (JBO) |
| August 28-September 05 | August 31, 11:00 | α-Aurigids (AUR) |
| September 05-September 21 | September 09, 06:00 | September ε-Perseids (SPE) |
| October 06-October 10 | October 18, 13:00 | Draconids (DRA) |
| November 15-November 25 | November 21 | α-Monocerotids (AMO) |
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.
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.
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 03 January 2024 at 0000 UT, 10 January at 0600 UT, 17 January at 1200 UT, 24 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 09 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.
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).
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:
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 2024 World Day Schedule which lists Incoherent Scatter coordinated observation days. 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).
For the ionospheric drift or wind measurement by the various radio techniques, observations are recommended to be concentrated on the weeks including RWDs.
For travelling ionosphere disturbances, propose special periods for coordinated measurements of gravity waves induced by magnetospheric activity, probably on selected PRWDs and RWDs.
For the ionospheric absorption program half-hourly observations are made at least on all RWDs and half-hourly tabulations sent to WDCs. Observations should be continuous on solar eclipse days for stations in the eclipse zone and in its conjugate area. Special efforts should be made to obtain daily absorption measurements at temperate latitude stations during the period of Absorption Winter Anomaly, particularly on days of abnormally high or abnormally low absorption (approximately October-March, Northern Hemisphere; April-September, Southern Hemisphere).
For back-scatter and forward scatter programs, observations should be made and analyzed at least on all RWDs.
For synoptic observations of mesospheric (D region) electron densities, several groups have agreed on using the RGD for the hours around noon.
For ELF noise measurements of earth-ionosphere cavity resonances any special effort should be concentrated during WGIs.
It is recommended that more intensive observations in all programs be considered on days of unusual meteor activity.
Particular efforts should be made to carry out an intensified program on the RGD -- each Wednesday, UT. A desirable goal would be the scheduling of meteorological rocketsondes, ozone sondes and radiometer sondes on these days, together with maximum-altitude rawinsonde ascents at both 0000 and 1200 UT.
During WGI and STRATWARM Alert Intervals, intensified programs are also desirable, preferably by the implementation of RGD-type programs (see above) on Mondays and Fridays, as well as on Wednesdays.
The World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) integrates many monitoring and research activities involving measurement of atmospheric composition, and serves as an early warning system to detect further changes in atmospheric concentrations of greenhouse gases, changes in the ozone layer and in the long range transport of pollutants, including acidity and toxicity of rain as well as of atmospheric burden of aerosols (dirt and dust particles).
Observatories making specialized studies of solar phenomena, particularly using new or complex techniques, such that continuous observation or reporting is impractical, are requested to make special efforts to provide to WDCs data for solar eclipse days, RWDs and during PROTON/FLARE ALERTS. The attention of those recording solar noise spectra, solar magnetic fields and doing specialized optical studies is particularly drawn to this recommendation.
Program within the SCOSTEP (Scientific Committee on Solar-Terrestrial Physics): 2020-2024. PRESTO's goals are to "address the predictability of 1) space weather on timescales from seconds to days and months, including processes at the Sun, in the heliosphere and in the Earth’s magnetosphere, ionosphere and atmosphere, and 2) sub-seasonal to decadal and centennial variability of the Sun-Earth system, with a special focus on climate impacts and a link to the World Climate Research Program (WCRP) Grand Challenge Near-Term Climate Predictions as well as the IPCC". PRESTO has three pillars: 1) Sun, interplanetary space, and geospace. 2) Space Weather and the Earth's atmosphere. 3) Solar activity and its influence on the climate of the Earth System. Detailed information on the PRESTO program is available at https://scostep.org/presto/.
ILWS (International Living With a Star) International effort to stimulate, strengthen, and coordinate space research to understand the governing processes of the connected Sun-Earth System as an integrated entity.
ISWI (International Space Weather Initiative) -- a program of international cooperation to advance space weather science by a combination of instrument deployment, analysis and interpretation of space weather data from the deployed instruments in conjunction with space data, and communicate the results to the public and students. The goal of the ISWI is to develop the scientific insight necessary to understand the science, and to reconstruct and forecast near-Earth space weather. ISWI runs science workshops, capacity building activities, and space science schools.
Experimenters should take into account that observational efforts in other disciplines tend to be intensified on the days marked on the Calendar, and schedule balloon and rocket experiments accordingly if there are no other geophysical reasons for choice. In particular it is desirable to make rocket measurements of ionospheric characteristics on the same day at as many locations as possible; where feasible, experimenters should endeavor to launch rockets to monitor at least normal conditions on the Quarterly World Days (QWDs) or on RWDs, since these are also days when there will be maximum support from ground observations. Also, special efforts should be made to assure recording of telemetry on QWDs and Airglow and Aurora Periods of experiments on satellites and of experiments on spacecraft in orbit around the Sun.
Of particular interest are both predicted and unexpected showers from the encounter with recent dust ejecta of comets (meteor outbursts). The period of activity, level of activity, and magnitude distributions need to be determined in order to provide ground truth for comet dust ejection and meteoroid stream dynamics models. Individual orbits of meteoroids can also provide insight into the ejection circumstances. If a new (1-2 hour duration) shower is observed due to the crossing of the 1-revolution dust trail of a (yet unknown) Earth threatening long-period comet, observers should pay particular attention to a correct determination of the radiant and time of peak activity in order to facilitate predictions of future encounters. Observations of meteor outbursts should be reported to the I.A.U. Minor Planet Center (mpc@cfa.harvard.edu) and International Meteor Organization (visual@imo.net). The activity curve, mean orbit, and particle size distribution of minor annual showers need to be characterised in order to understand their relationship to the dormant comets among near-Earth objects. Annual shower observations should be reported to national meteor organizations, or directly to the International Meteor Organization. Meteoroid orbits are collected by the IAU Meteor Data Center.
The International Space Environment Service (ISES) is a space weather service organization currently comprised of globally distributed Regional Warning Centers, Associate Warning Centers, and one Collaborative Expert Center (European Space Agency). ISES collaborates with the World Meteorological Organization (WMO) and other international organizations, including the Committee on Space Research (COSPAR), the UN Committee on the Peaceful Uses of Outer Space (COPUOS), the International Union of Radio Science (URSI), and the International Union of Geodesy and Geophysics (IUGG). ISES works in close cooperation with the WMO and other international organizations to benefit from complementary activities that enhance the availability of data, the exchange of information, and the improvement and dissemination of services, recognizing the mutual interest in global data acquisition and information exchange, in common application sectors, and in understanding and predicting the coupled Earth-Sun environment.
The mission of ISES is to deliver, coordinate and improve operational space weather services. This is accomplished through the rapid exchange of space environment information; the sharing of best practices for data analysis and product development; and the open dissemination of products and services. ISES is organized and operated for the benefit of the international space weather user community.
Through its members, ISES shares data and forecasts and provides space weather products and services to users in their regions. Products and services include but are not limited to: forecasts, watches, warnings, and alerts of solar, magnetospheric, geomagnetic and ionospheric conditions; extensive space environment data; customer-focused event analyses; and long-range predictions of the solar cycle.
This Calendar for 2024 has been drawn up by Dr. R. A. D. Fiori of the ISES Steering Committee. Similar Calendars are issued annually beginning with the IGY, 1957-58, and are published in various widely available scientific publications. PDF versions of the past calendars are available online.
Published for the International Council of Scientific Unions and with financial assistance of UNESCO for many years.
The website for the International Geophysical Calendar, including recent versions, can be found here.