Accession Number : ADA194505

Title :   Atmospheric Angular Momentum and Length of Day.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Benedict, William L

PDF Url : ADA194505

Report Date : Mar 1988

Pagination or Media Count : 63

Abstract : Changes in the globally integrated absolute angular momentum of the atmosphere were computed from the Fleet Numerical Oceanography Center NOGAPS wind analyses and compared to astronomically measured changes in length of day (LOD) obtained from the U.S. Naval Observatory, Washington D.C. The two time series were subjected to both time and frequency domain analysis. In the time domain, digital filters were used to isolate seasonal and subseasonal components. In the frequency domain, energy density, coherence and phase were computed over periods from 2 days to 1000 days. Over 90% of the total variance in astronomically determined LOD can be explained by meteorological phenomena. Fluctuations in LOD are coherent and in phase with fluctuations in the globally integrated angular momentum of the Earth's shell (crust, mantle and oceans; liquid core is excluded) at almost all periods less than 365 days. Annual fluctuations in LOD appear to originate in the midlatitudes and propagate equatorward. Subseasonal fluctuations (30 to 100 day periods) appear to be a tropical phenomena. Keywords: Length of Day; Atmospheric angular momentum; Theses; Computer programs.

Descriptors :   *ANGULAR MOMENTUM, *ATMOSPHERES, *LENGTH, *TIME SERIES ANALYSIS, COMPUTER PROGRAMS, DAY, DENSITY, DIGITAL FILTERS, EARTH(PLANET), ENERGY, INTEGRATED SYSTEMS, LIQUIDS, METEOROLOGICAL PHENOMENA, OCEANS, SHELLS(STRUCTURAL FORMS), THESES, TIME DOMAIN, VARIATIONS, WIND, EARTH CORE

Subject Categories : Atmospheric Physics
      Astronomy

Distribution Statement : APPROVED FOR PUBLIC RELEASE