scholarly journals New Altimetric Estimates of Mode-1 M2 Internal Tides in the Central North Pacific Ocean

2009 ◽  
Vol 39 (7) ◽  
pp. 1669-1684 ◽  
Author(s):  
Zhongxiang Zhao ◽  
Matthew H. Alford
Keyword(s):  
Pacific Ocean ◽  
Spatial Resolution ◽  
North Pacific ◽  
Numerical Models ◽  
North Pacific Ocean ◽  
Internal Tide ◽  
Internal Tides ◽  
New Technique ◽  
The North ◽  
Central North Pacific

Abstract New estimates of mode-1 M2 internal tide energy flux are computed from an extended Ocean Topography Experiment (TOPEX)/Poseidon (T/P) altimeter dataset that includes both the original and tandem tracks, improving spatial resolution over previous estimates from O(500 km) to O(250 km). Additionally, a new technique is developed that allows separate resolution of northward and southward components. Half-wavelength features previously seen in unseparated estimates are shown to be due to the superposition of northward and southward wave trains. The new technique and higher spatial resolution afford a new view of mode-1 M2 internal tides in the central North Pacific Ocean. As with all altimetric estimates, only the coherent or phase-locked signals are detectable owing to the long repeat period of the tracks. Emanating from specific generation sites consistent with predictions from numerical models, internal tidal beams 1) are as narrow as 200 km and 2) propagate a longer distance than previously observed. Two northward internal tidal beams radiating from the Hawaiian Ridge, previously obscured by coarse resolution and the southward Aleutian beam, are now seen to propagate more than 3500 km across the North Pacific Ocean to reach the Alaskan shelf. The internal tidal beams are much better resolved than in previous studies, resulting in better agreement with moored flux estimates.

Development of a Long-Range Lightning Detection Network for the Pacific: Construction, Calibration, and Performance*

2009 ◽  
Vol 26 (2) ◽  
pp. 145-166 ◽  
Author(s):  
Antti T. Pessi ◽  
Steven Businger ◽  
K. L. Cummins ◽  
N. W. S. Demetriades ◽  
M. Murphy ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Long Range ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Cloud Microphysics ◽  
Lightning Flash ◽  
Central Pacific ◽  
The North ◽  
Lightning Detection ◽  
Central North Pacific

Abstract The waveguide between the earth’s surface and the ionosphere allows very low-frequency (VLF) emissions generated by lightning, called sferics, to propagate over long distances. The new Pacific Lightning Detection Network (PacNet), as a part of a larger long-range lightning detection network (LLDN), utilizes this attribute to monitor lightning activity over the central North Pacific Ocean with a network of ground-based lightning detectors that have been installed on four widely spaced Pacific islands (400–3800 km). PacNet and LLDN sensors combine both magnetic direction finding (MDF) and time-of-arrival (TOA)-based technology to locate a strike with as few as two sensors. As a result, PacNet/LLDN is one of the few observing systems, outside of geostationary satellites, that provides continuous real-time data concerning convective storms throughout a synoptic-scale area over the open ocean. The performance of the PacNet/LLDN was carefully assessed. Long-range lightning flash detection efficiency (DE) and location accuracy (LA) models were developed with reference to accurate data from the U.S. National Lightning Detection Network (NLDN). Model calibration procedures are detailed, and comparisons of model results with lightning observations from the PacNet/LLDN in correlation with NASA’s Lightning Imaging Sensor (LIS) are presented. The daytime and nighttime flash DE in the north-central Pacific is in the range of 17%–23% and 40%–61%, respectively. The median LA is in the range of 13–40 km. The results of this extensive analysis suggest that the DE and LA models are reasonably able to reproduce the observed performance of PacNet/LLDN. The implications of this work are that the DE and LA model outputs can be used in quantitative applications of the PacNet/LLDN over the North Pacific Ocean and elsewhere. For example, by virtue of the relationship between lightning and rainfall rates, these data also hold promise as input for NWP models as a proxy for latent heat release in convection. Moreover, the PacNet/LLDN datastream is useful for investigations of storm morphology and cloud microphysics over the central North Pacific Ocean. Notably, the PacNet/LLDN lightning datastream has application for planning transpacific flights and nowcasting of squall lines and tropical storms.

scholarly journals Neural Network Approach to Retrieving Ocean Subsurface Temperatures from Surface Parameters Observed by Satellites

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 388
Author(s):  
Hao Cheng ◽  
Liang Sun ◽  
Jiagen Li
Keyword(s):  
Neural Network ◽  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Sea Surface ◽  
Satellite Measurements ◽  
Surface Parameters ◽  
The North ◽  
The North Pacific ◽  
Bpnn Model

The extraction of physical information about the subsurface ocean from surface information obtained from satellite measurements is both important and challenging. We introduce a back-propagation neural network (BPNN) method to determine the subsurface temperature of the North Pacific Ocean by selecting the optimum input combination of sea surface parameters obtained from satellite measurements. In addition to sea surface height (SSH), sea surface temperature (SST), sea surface salinity (SSS) and sea surface wind (SSW), we also included the sea surface velocity (SSV) as a new component in our study. This allowed us to partially resolve the non-linear subsurface dynamics associated with advection, which improved the estimated results, especially in regions with strong currents. The accuracy of the estimated results was verified with reprocessed observational datasets. Our results show that the BPNN model can accurately estimate the subsurface (upper 1000 m) temperature of the North Pacific Ocean. The corresponding mean square errors were 0.868 and 0.802 using four (SSH, SST, SSS and SSW) and five (SSH, SST, SSS, SSW and SSV) input parameters and the average coefficients of determination were 0.952 and 0.967, respectively. The input of the SSV in addition to the SSH, SST, SSS and SSW therefore has a positive impact on the BPNN model and helps to improve the accuracy of the estimation. This study provides important technical support for retrieving thermal information about the ocean interior from surface satellite remote sensing observations, which will help to expand the scope of satellite measurements of the ocean.

scholarly journals Nursery origin and population connectivity of swordfish Xiphias gladius in the North Pacific Ocean

2021 ◽  
Author(s):  
R. J. David Wells ◽  
Veronica A. Quesnell ◽  
Robert L. Humphreys ◽  
Heidi Dewar ◽  
Jay R. Rooker ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Population Connectivity ◽  
The North ◽  
Xiphias Gladius ◽  
The North Pacific

scholarly journals Direct observations of basin-wide acidification of the North Pacific Ocean

2010 ◽  
Vol 37 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Robert H. Byrne ◽  
Sabine Mecking ◽  
Richard A. Feely ◽  
Xuewu Liu
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
The North ◽  
Direct Observations ◽  
The North Pacific
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