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Possible Role of the Oceans in the Variations of Length of Day at High Frequencies

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At the U.S. Naval Observatory USNO, there are a few research studies as well as operational tasks that use data available from Global Geophysical Fluid Center GGFC web and ftp sites. This research includes investigating the excitation mechanisms of Earth rotation variability on all time scales, examining the global water budget and its role in exciting Earth rotation, researching the usefulness of ocean model nowcastforecast models in predicting Earth rotation, and investigating the role of geophysical fluids in gravity field variations on GPS satellites. This presentation briefly covers the USNOs ongoing research to examine high frequency variations in excess Length of Day LOD. It also will highlight the GGFC datasets used in the study as well as raise some issues with respect to the currently available GGFC datasets and what the author would like to see in the future to make this type of research easier. In closing, the author would like to make the following two suggestions on what the GGFC could do to improve the usefulness of the GGFC datasets. First, the GGFC must make sure that the special bureaus properly document their existing datasets. This includes correcting the dataset documentation that is clearly inaccurate and incomplete. Finally, the IERS GGFC could work on expanding the number of regularly updated atmospheric datasets that are currently available, adding near-real timedaily updated atmospheric AM datasets that use Non-IB, IB, and dynamic barometer corrections, and adding nowcastforecast global oceanic AM datasets. These improvements would greatly increase the usefulness of IERS GGFC datasets in addressing current and future research needs.

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  • Astronomy
  • Physical and Dynamic Oceanography

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