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Title: Effects of dynamic long-period 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 earth-ocean system as the ratio, in the frequency domain, of the tidal change in Earth's rotation rate to the tide-generating potential. Amplitudes and phases of k for the monthly, fortnightly, and 9-day lunar tides are estimated from 2 1/2 years of very long baseline interferometry UTI observations (both 5-day 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 earth-ocean system. The predictions confirm earlier results which found that dynamic effects of the longer-period 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 satellite-observed 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 » cannot exceed 2%.« less

Authors:
;  [1]
  1. 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 0148-0227
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 long-period 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 long-period 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 long-period ocean tides on changes in Earth's rotation rate". United States. doi:10.1029/JB095iB05p06751.
@article{osti_5036069,
title = {Effects of dynamic long-period 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 earth-ocean system as the ratio, in the frequency domain, of the tidal change in Earth's rotation rate to the tide-generating potential. Amplitudes and phases of k for the monthly, fortnightly, and 9-day lunar tides are estimated from 2 1/2 years of very long baseline interferometry UTI observations (both 5-day 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 earth-ocean system. The predictions confirm earlier results which found that dynamic effects of the longer-period 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 satellite-observed 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 = {0148-0227},
number = ,
volume = 95:B5,
place = {United States},
year = {1990},
month = {5}
}