Rotated Power Spectra of Microseisms

Cross-power and coherency as a function of period and azimuth have been calculated for several seismic stations during the course of a microseismic storm in the north Pacific. These data indicate that in addition to the predicted Rayleigh waves, a large fraction of the observed ground motion must be due to other wave types, most of which have predominantly vertical motion. The data indicate that the angle subtended by the source of the waves increases with distance, suggesting that wave interactions at the coastline may be a major factor in the observed disturbances on the continent.

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Longer Time-Scale Variability of Atmospheric Vertical Motion over the Tibetan Plateau and North Pacific and the Climate in East Asia

Atmosphere ◽

10.3390/atmos12050630 ◽

2021 ◽

Vol 12 (5) ◽

pp. 630

Author(s):

Rongxiang Tian ◽

Yaoming Ma ◽

Weiqiang Ma ◽

Xiuyi Zhao ◽

Duo Zha

Keyword(s):

Tibetan Plateau ◽

East Asia ◽

Negative Correlation ◽

North Pacific ◽

Maximum Velocity ◽

Vertical Motion ◽

The Tibetan Plateau ◽

Upward Movement ◽

The North ◽

The North Pacific

The vertical motion of air is closely related to the amount of precipitation that falls in a particular region. The Tibetan Plateau and the North Pacific are important determinants of the East Asian climate. We use climate diagnosis and statistical analysis to study the vertical motion of the air over the North Pacific and Tibetan Plateau and the relationship between the vertical motion of air over them and the climate in East Asia. Here we show that there is a downward movement of air over the Tibetan Plateau during the winter, with a maximum velocity of downward movement at 500 hPa, whereas there is an upward movement of air with a maximum velocity of upward movement at 600 hPa during the summer. Precipitation in East Asia has a significant negative correlation (The correlation coefficient exceeds −0.463 and confidence level is greater than 99%) with the vertical motion of air over the Tibetan Plateau and the North Pacific during both the winter and summer. There is also a negative correlation of precipitation in the region south of the Yangtze River with the vertical motion of air over the Tibetan Plateau in winter, whereas the area of negative correlation to the vertical motion of air over the North Pacific in winter is located to the east of the Tibetan Plateau and the Yangtze–Huaihe river basin. The research results provide a climatic framework for the vertical motion of air over both the Tibetan Plateau and the North Pacific.

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On dispersion of Rayleigh waves from the North Pacific earthquake of November 10, 1938*

Bulletin of the Seismological Society of America ◽

10.1785/bssa0310040303 ◽

1941 ◽

Vol 31 (4) ◽

pp. 303-307

Author(s):

J. F. De Lisle

Keyword(s):

Crustal Structure ◽

Bering Sea ◽

North Pacific ◽

Rayleigh Waves ◽

Great Circle ◽

Average Thickness ◽

Crustal Layer ◽

The North ◽

The North Pacific ◽

Hypothetical Structure

Abstract Rayleigh waves from the North Pacific earthquake of November 10, 1938, have been investigated in different azimuths for dispersion. Using dispersion curves of Jeffreys based on the hypothetical structure of a single crustal layer, the average thickness of this layer along great circle paths from Bering Sea to each observatory has been calculated. The values found give a comparison between Pacific and continental crustal structure which affords confirmation of other evidence on this point.

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Running into Whales: The History of the North Pacific from below the Waves

The American Historical Review ◽

10.1093/ahr/118.2.349 ◽

2013 ◽

Vol 118 (2) ◽

pp. 349-377 ◽

Cited By ~ 11

Author(s):

Ryan Tucker Jones

Keyword(s):

North Pacific ◽

The North ◽

History Of ◽

The Waves ◽

The North Pacific

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Accumulation reconstruction and water isotope analysis for 1735–1997 of an ice core from the Ushkovsky volcano, Kamchatka, and their relationships to North Pacific climate records

Climate of the Past Discussions ◽

10.5194/cpd-9-2153-2013 ◽

2013 ◽

Vol 9 (2) ◽

pp. 2153-2181 ◽

Cited By ~ 5

Author(s):

T. Sato ◽

T. Shiraiwa ◽

R. Greve ◽

H. Seddik ◽

E. Edelmann ◽

...

Keyword(s):

North Pacific ◽

North Pacific Ocean ◽

Ice Core ◽

Power Spectra ◽

Ice Age ◽

Northwest Pacific ◽

Accumulation Rates ◽

The North ◽

Decadal Scale ◽

The North Pacific

Abstract. To investigate past climate change in the Northwest Pacific region, an ice core was retrieved in June 1998 from the Gorshkov crater glacier at the top of the Ushkovsky volcano, in central Kamchatka. Hydrogen isotope (δD) analysis and past accumulation reconstructions were conducted to a depth of 140.7 m, dated to 1735. Two accumulation reconstruction methods were applied with the Salamatin and the Elmer/Ice ice flow models. Reconstructed accumulation rates and δD were significantly correlated with North Pacific surface temperature. This, and a significant correlation of δD with the North Pacific Gyre Oscillation (NPGO) index implies that NPGO data is contained in this record. Wavelet analysis shows that the ice core records have significant multi-decadal power spectra up to the late 19th century. The multi-decadal periods of reconstructed accumulation rates change at around 1850 in the same way as do Northeast Pacific ice core and tree ring records. The loss of multi-decadal scale power spectra of δD and the 6‰ increase in its average value occurred around 1880. Thus the core record confirms that the periodicity of precipitation for the entire North Pacific changed between the end of the Little Ice Age through the present due to changes in conditions in the North Pacific Ocean.

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