EOP Combination and Analysis Center

EOP Combination and Analysis Center  (EOP CAC)  of the Main Merological Center of the State Service for Time, Frequency and Earth rotation parameters (MMC SSTF) provides the functioning of MMC SSTF as EOP combination and analysis center.

State Service for Time, Frequency and Earth orientation parameters  (SSTF)  is permanently functioning system of Russian facilities and organization incorporated in common scientific, technical and metrological activity, which includes continuous reproduction, keeping and dissemenation of the precise values of time and frequency, national time scale UTC (SU)  as well as combination and dissemenation SSTF EOP.

Federal Agency on Technical Regulating and Metrology (ROSSTANDART) is responcible of SSTF activity.

The Main Merological Center of the State Service for Time, Frequency and Earth rotation parameters (MMC SSTF) - structure unit of the SSTF which is responcible of science, methodical and operative providing of SSTF activity.

This MMC SSTF activity has been charged by governmental decree №225 which aproved the provision "About State Service for Time, Frequency and Earth rotation parameters".

Nowdays, the role of MMC SSTF plays research division №7 (RD-7) of federal state unitary enterprise "National research institute of physicotechnical and radio engineering measurements" (FSUE "VNIIFTRI").

 

27.03.2026

 

What happens with the rotation of the Earth?

 

In recent publications, articles have begun to appear about the slowing down of the Earth's rotation due to melting glaciers.

While we note that approximately over the last 70 years, the Earth's rotation has accelerated, and the length of the day has decreased.

Where do such contradictions come from and what is the point here?

If we smooth out the behavior of the angular velocity of the Earth's rotation over all paleodata by a polynomial of the fourth degree, it turns out that the Earth's rotation slows down, and the duration of the day increases.

Let's name the nature of the change in the angular velocity of the Earth's rotation, corresponding to this polynomial, is the main trend of variation in the angular velocity of the Earth's rotation.

In this case, the section of the polynomial corresponding to the present time gives the rate of deceleration of rotation.

The Earth takes about 1.5 ms per century.

From observations of satellite laser ranging, we have about 1.73 ms per hundred years.

If we combine the individual paleo-results with a smooth curve, it turns out that the Earth's rotation speed fluctuated relative to a smooth polynomial curve.

Considering that the rate of deceleration was much higher before that, compared to the average value of 1.5 ms per century, it is not surprising that the Earth has been accelerating for the last 70 years (considering that the true rate of increase in the length of the day tends to fluctuate near its average value).

But it is also true that its acceleration will eventually give way to deceleration.

These arguments are the result of considering behavior the rotation of the Earth as a whole, without dividing its causes into separate influencing factors, of which there are many. Those who are interested in this issue in more detail are recommended to read the article posted on our website.

MMC SSTF, Mendeleevo, Moscow reg.