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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 15:48:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 15:48:51 +0000
commit4f01be51e0a45f022198d4286d4375636a29b714 (patch)
treed99dab2786b89a9ca35f59f4c88749649ad859e7 /leap-seconds.list
parentInitial commit. (diff)
downloadtzdata-4f01be51e0a45f022198d4286d4375636a29b714.tar.xz
tzdata-4f01be51e0a45f022198d4286d4375636a29b714.zip
Adding upstream version 2024a.upstream/2024aupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+# ATOMIC TIME.
+# The Coordinated Universal Time (UTC) is the reference time scale derived
+# from The "Temps Atomique International" (TAI) calculated by the Bureau
+# International des Poids et Mesures (BIPM) using a worldwide network of atomic
+# clocks. UTC differs from TAI by an integer number of seconds; it is the basis
+# of all activities in the world.
+#
+#
+# ASTRONOMICAL TIME (UT1) is the time scale based on the rate of rotation of the earth.
+# It is now mainly derived from Very Long Baseline Interferometry (VLBI). The various
+# irregular fluctuations progressively detected in the rotation rate of the Earth lead
+# in 1972 to the replacement of UT1 by UTC as the reference time scale.
+#
+#
+# LEAP SECOND
+# Atomic clocks are more stable than the rate of the earth rotation since the latter
+# undergoes a full range of geophysical perturbations at various time scales: lunisolar
+# and core-mantle torques, atmospheric and oceanic effetcs, etc.
+# Leap seconds are needed to keep the two time scales in agreement, i.e. UT1-UTC smaller
+# than 0.9 second. Therefore, when necessary a "leap second" is applied to UTC.
+# Since the adoption of this system in 1972 it has been necessary to add a number of seconds to UTC,
+# firstly due to the initial choice of the value of the second (1/86400 mean solar day of
+# the year 1820) and secondly to the general slowing down of the Earth's rotation. It is
+# theorically possible to have a negative leap second (a second removed from UTC), but so far,
+# all leap seconds have been positive (a second has been added to UTC). Based on what we know about
+# the earth's rotation, it is unlikely that we will ever have a negative leap second.
+#
+#
+# HISTORY
+# The first leap second was added on June 30, 1972. Until yhe year 2000, it was necessary in average to add a
+# leap second at a rate of 1 to 2 years. Since the year 2000 leap seconds are introduced with an
+# average interval of 3 to 4 years due to the acceleration of the Earth rotation speed.
+#
+#
+# RESPONSABILITY OF THE DECISION TO INTRODUCE A LEAP SECOND IN UTC
+# The decision to introduce a leap second in UTC is the responsibility of the Earth Orientation Center of
+# the International Earth Rotation and reference System Service (IERS). This center is located at Paris
+# Observatory. According to international agreements, leap seconds should only be scheduled for certain dates:
+# first preference is given to the end of December and June, and second preference at the end of March
+# and September. Since the introduction of leap seconds in 1972, only dates in June and December were used.
+#
+# Questions or comments to:
+# Christian Bizouard: christian.bizouard@obspm.fr
+# Earth orientation Center of the IERS
+# Paris Observatory, France
+#
+#
+#
+# COPYRIGHT STATUS OF THIS FILE
+# This file is in the public domain.
+#
+#
+# VALIDITY OF THE FILE
+# It is important to express the validity of the file. These next two dates are
+# given in units of seconds since 1900.0.
+#
+# 1) Last update of the file.
+#
+# Updated through IERS Bulletin C (https://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat)
+#
+# The following line shows the last update of this file in NTP timestamp:
+#
+#$ 3913697179
+#
+# 2) Expiration date of the file given on a semi-annual basis: last June or last December
+#
+# File expires on 28 December 2024
+#
+# Expire date in NTP timestamp:
+#
+#@ 3944332800
+#
+#
+# LIST OF LEAP SECONDS
+# NTP timestamp (X parameter) is the number of seconds since 1900.0
+#
+# MJD: The Modified Julian Day number. MJD = X/86400 + 15020
+#
+# DTAI: The difference DTAI= TAI-UTC in units of seconds
+# It is the quantity to add to UTC to get the time in TAI
+#
+# Day Month Year : epoch in clear
+#
+#NTP Time DTAI Day Month Year
+#
+2272060800 10 # 1 Jan 1972
+2287785600 11 # 1 Jul 1972
+2303683200 12 # 1 Jan 1973
+2335219200 13 # 1 Jan 1974
+2366755200 14 # 1 Jan 1975
+2398291200 15 # 1 Jan 1976
+2429913600 16 # 1 Jan 1977
+2461449600 17 # 1 Jan 1978
+2492985600 18 # 1 Jan 1979
+2524521600 19 # 1 Jan 1980
+2571782400 20 # 1 Jul 1981
+2603318400 21 # 1 Jul 1982
+2634854400 22 # 1 Jul 1983
+2698012800 23 # 1 Jul 1985
+2776982400 24 # 1 Jan 1988
+2840140800 25 # 1 Jan 1990
+2871676800 26 # 1 Jan 1991
+2918937600 27 # 1 Jul 1992
+2950473600 28 # 1 Jul 1993
+2982009600 29 # 1 Jul 1994
+3029443200 30 # 1 Jan 1996
+3076704000 31 # 1 Jul 1997
+3124137600 32 # 1 Jan 1999
+3345062400 33 # 1 Jan 2006
+3439756800 34 # 1 Jan 2009
+3550089600 35 # 1 Jul 2012
+3644697600 36 # 1 Jul 2015
+3692217600 37 # 1 Jan 2017
+#
+# A hash code has been generated to be able to verify the integrity
+# of this file. For more information about using this hash code,
+# please see the readme file in the 'source' directory :
+# https://hpiers.obspm.fr/iers/bul/bulc/ntp/sources/README
+#
+#h 9dac5845 8acd32c0 2947d462 daf4a943 f58d9391