Effects of dynamic longperiod ocean tides on changes in Earth's rotation rate
Abstract
As a generalization of the zonal response coefficient first introduced by Agnew and Farrell (1978), the authors define the zonal response function k of the solid earthocean system as the ratio, in the frequency domain, of the tidal change in Earth's rotation rate to the tidegenerating potential. Amplitudes and phases of k for the monthly, fortnightly, and 9day lunar tides are estimated from 2 1/2 years of very long baseline interferometry UTI observations (both 5day and daily time series), corrected for atmospheric angular momentum effects using NMC wind and pressure series. Using the dynamic ocean tide model of Dickman (1988a, 1989a), the authors predict amplitudes and phases of k for an elastic earthocean system. The predictions confirm earlier results which found that dynamic effects of the longerperiod ocean tides reduce the amplitude of k by about 1%. However, agreement with the observed k is best achieved for all three tides if the predicted tide amplitudes are combined with the much larger satelliteobserved ocean tide phases; in these cases the dynamic tidal effects reduce k by up to 8%. Finally, comparison between the observed and predicted amplitudes of k implies that anelastic effects on Earth's rotation at periods less than fortnightlymore »
 Authors:

 State Univ. of New York, Binghamton (United States)
 Publication Date:
 OSTI Identifier:
 5036069
 Resource Type:
 Journal Article
 Journal Name:
 Journal of Geophysical Research; (United States)
 Additional Journal Information:
 Journal Volume: 95:B5; Journal ID: ISSN 01480227
 Country of Publication:
 United States
 Language:
 English
 Subject:
 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; EARTH PLANET; ROTATION; TIDE; FLUID MECHANICS; AMPLITUDES; ANGULAR MOMENTUM; ATMOSPHERIC PRESSURE; GENERAL CIRCULATION MODELS; INTERFEROMETRY; OCEANIC CIRCULATION; RESPONSE FUNCTIONS; SEAS; VARIATIONS; WIND; FUNCTIONS; MATHEMATICAL MODELS; MECHANICS; MOTION; PLANETS; SURFACE WATERS; 540310*  Environment, Aquatic Basic Studies (1990); 580000  Geosciences
Citation Formats
Nam, Y S, and Dickman, S R. Effects of dynamic longperiod ocean tides on changes in Earth's rotation rate. United States: N. p., 1990.
Web. doi:10.1029/JB095iB05p06751.
Nam, Y S, & Dickman, S R. Effects of dynamic longperiod ocean tides on changes in Earth's rotation rate. United States. doi:10.1029/JB095iB05p06751.
Nam, Y S, and Dickman, S R. Thu .
"Effects of dynamic longperiod ocean tides on changes in Earth's rotation rate". United States. doi:10.1029/JB095iB05p06751.
@article{osti_5036069,
title = {Effects of dynamic longperiod ocean tides on changes in Earth's rotation rate},
author = {Nam, Y S and Dickman, S R},
abstractNote = {As a generalization of the zonal response coefficient first introduced by Agnew and Farrell (1978), the authors define the zonal response function k of the solid earthocean system as the ratio, in the frequency domain, of the tidal change in Earth's rotation rate to the tidegenerating potential. Amplitudes and phases of k for the monthly, fortnightly, and 9day lunar tides are estimated from 2 1/2 years of very long baseline interferometry UTI observations (both 5day and daily time series), corrected for atmospheric angular momentum effects using NMC wind and pressure series. Using the dynamic ocean tide model of Dickman (1988a, 1989a), the authors predict amplitudes and phases of k for an elastic earthocean system. The predictions confirm earlier results which found that dynamic effects of the longerperiod ocean tides reduce the amplitude of k by about 1%. However, agreement with the observed k is best achieved for all three tides if the predicted tide amplitudes are combined with the much larger satelliteobserved ocean tide phases; in these cases the dynamic tidal effects reduce k by up to 8%. Finally, comparison between the observed and predicted amplitudes of k implies that anelastic effects on Earth's rotation at periods less than fortnightly cannot exceed 2%.},
doi = {10.1029/JB095iB05p06751},
journal = {Journal of Geophysical Research; (United States)},
issn = {01480227},
number = ,
volume = 95:B5,
place = {United States},
year = {1990},
month = {5}
}