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2014
Ying, YZ, Bean CJ, Bromirski PD.  2014.  Propagation of microseisms from the deep ocean to land. Geophysical Research Letters. 41:6374-6379.   10.1002/2014gl060979   AbstractWebsite

Ocean-generated microseisms are faint Earth vibrations that result from pressure fluctuations at the sea floor generated by the interaction between ocean surface gravity waves, and are continuously recorded as low frequency seismic noise. Here we investigate microseism propagation away from deep-ocean source regions using the spectral element method for an oceanic model that contains realistic northeast Atlantic Ocean irregular-layered structure composed of water, sediment, and upper crust. It also includes structural heterogeneities and continental slope and shelf bathymetry. Numerical simulations of coupled acoustic and elastic wave propagation in both simplified models and the full realistic model show that most microseism energy is confined to sediment and water column waveguides. We also show that a significant portion of microseism energy is reflected back to the deep ocean by the continental slope, while only a small fraction of deep-ocean-generated microseism energy reaches land. We conclude that terrestrially observed microseisms are largely generated in shallow water on continental shelves.

Vose, RS, Applequist S, Bourassa MKA, Pryor SC, Barthelmie RJ, Blanton B, Bromirski PD, Brooks HOE, DeGaetano AT, Dole RM, Easterling DR, Jensen RE, Karl TR, Katz RW, Klink K, Kruk MC, Kunkel KE, MacCracken MC, Peterson TSC, Shein K, Thomas BR, Walsh JE, Wang XLL, Wehner MF, Wuebbles DJ, Young RS.  2014.  Monitoring and understanding changes in extremes: Extratropical storms, winds, and waves. Bulletin of the American Meteorological Society. 95:377-386.   10.1175/bams-d-12-00162.1   AbstractWebsite

This scientific assessment examines changes in three climate extremesextratropical storms, winds, and waveswith an emphasis on U.S. coastal regions during the cold season. There is moderate evidence of an increase in both extratropical storm frequency and intensity during the cold season in the Northern Hemisphere since 1950, with suggestive evidence of geographic shifts resulting in slight upward trends in offshore/coastal regions. There is also suggestive evidence of an increase in extreme winds (at least annually) over parts of the ocean since the early to mid-1980s, but the evidence over the U.S. land surface is inconclusive. Finally, there is moderate evidence of an increase in extreme waves in winter along the Pacific coast since the 1950s, but along other U.S. shorelines any tendencies are of modest magnitude compared with historical variability. The data for extratropical cyclones are considered to be of relatively high quality for trend detection, whereas the data for extreme winds and waves are judged to be of intermediate quality. In terms of physical causes leading to multidecadal changes, the level of understanding for both extratropical storms and extreme winds is considered to be relatively low, while that for extreme waves is judged to be intermediate. Since the ability to measure these changes with some confidence is relatively recent, understanding is expected to improve in the future for a variety of reasons, including increased periods of record and the development of climate reanalysis projects.