# Presentation information

Poster

Symbol S (Solid Earth Sciences) » S-GD Geodesy

# [S-GD23] Geodesy General Contributions / Global Geodetic Observing System

Mon. May 23, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Koji Matsuo(Geospatial Information Authority of Japan), Takahito Kazama(Graduate School of Science, Kyoto University), Ryoji Kawabata(Geospatial Information Authority of Japan)

5:15 PM - 6:30 PM

# [SGD23-P01] A proposal to avoid a leap second

Keywords:leap scond, avoid leap seconds

The method is shown to avoid the leap second, which needs no special operation for almost persons.
1. Decrease of rotational angular velocity: The maximum rotational angular velocity of the earth at the origin of the earth, is expressed by the following formula, because the centrifugal force caused by the angular velocity ωo should be less than gravity.
(In the following, **: power)
r × ωo**2 = g
where Radius of the earth r = 6378100 m
Standard gravitational acceleration g = 9.80665 m/s**2
Substituting these into the above,
At this value the force balances with the gravity.
The present earth has
Where ωo decreases exponentially,
log (ωp / ωo) = - k t (1)
Substituting followings into the above,
ωo / ωp = 1.240×10**-3/7.292×10**-5
= 16.98
log (ωo / ωp ) = 2.833
and the earth's age
t = 4.55 bil. years = 1.436×10**17 secs
We get
k = 1.973×10**-17/sec = 6.226×10**-10/year
= 0.623/bil.year
In past 15 years, the leap second has been substituted five times. Where the present period is T0 , the period T after three years is expressed as follows:
T - T0 = 1 sec
T - T0 = 2π(1/ω - 1/ωo)=2π (ωo - ω)/(ω×ωo)
Substituting the following into the above,
ω = ωo×e**(-kt)
We get
2π / ω{1-e**(-kt)} = 1sec
i.e. ω /2π = 1-e**(-kt) = kt