National Marine Environment Forecasting Center

Beijing, China

National Marine Environment Forecasting Center

Beijing, China
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Wei H.,Tianjin University of Science and Technology | Yuan C.,Tianjin University of Science and Technology | Lu Y.,Bedford Institute of Oceanography | Zhang Z.,National Marine Environment Forecasting Center | Luo X.,Tianjin University of Science and Technology
Journal of Geophysical Research: Oceans | Year: 2013

Forcing mechanisms of heat content variations in the Yellow Sea (YS) are studied through analysis of a hindcast simulator for 1958-2007 using a two-way nested global - Northwest Pacific model. During the cooling season (September to February of next year), changes in heat content integrated over the YS are primarily caused by variations in latent and sensible heat fluxes at surface, which can be further related to variations of the East Asian Winter Monsoon and the Arctic Oscillation. The lateral heat transport by the Yellow Sea Warm Current (YSWC) contributes to heat content variation in the deep region. Variation of the YSWC can be related to wind variation over the YS. During the warming season (March to August), variation in the changes of heat content in the upper layer is primarily caused by variation in shortwave radiation at surface, which can be related to variation in the atmospheric pressure system of the Western Pacific Subtropical High that influences the YS in summer. © 2013. American Geophysical Union. All Rights Reserved.


Wang P.-T.,National Marine Environment Forecasting Center | Wang P.-T.,State Oceanic Administration | Yu F.-J.,National Marine Environment Forecasting Center | Yu F.-J.,State Oceanic Administration | And 6 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2016

Fast and correctly characterizing tsunami source is crucial to accurate early warning of near-field tsunami. Although there is no way to implement forward quantitative calculation directly, a tsunami source can be inverted using real-time tsunami or seismic waveform records which are detected by Dart buoys, GPS buoys, tidal gauges and seismometers, respectively, and also by joint inversion using different sources data. Because different typical tsunami source models may come to different conclusions, it is important for tsunami early warning and tsunami research to learn about the applicability of different tsunami sources and assess the impacts of tsunami source characteristics differences of near-field tsunami. This study analyzed the effects of six different coseismic fault models on near-field numerical forecasting to the tsunami triggered by the March 11, 2011 Tohoku-oki earthquake. A variable nested algorithm was used to increase spatial resolution in the target region. The finest bathymetric grid resolution was 3 arcsec (approx. 90m). The present work focused on assessing the performance of the finite fault model and uniform slip model in near-field tsunami generation, propagation, inundation and their respective characteristic errors by comparing the simulated data with the measured data. From observed data of the Deep-Ocean Assessment and Reporting for Tsunamis (DART) network, Japan GPS buoys, we selected tide gauges along the coastline of Japan and post-even survey. The measured data were compared with forecasts to assess the sensitivity of the six different sources using error analysis. The results show that the characteristics of the energy distribution of near-field tsunami is much dependent on tsunami source geometry. In particular, the strike angle and slip are the most sensitive parameters for the energy distribution of near-field tsunami. Comparison indicates that finite fault models are more reasonable than uniform slip models in fitting maximum tsunami run-up height south of 39 °N coastal areas, where occurred the most serious tsunami disaster. A total of 32 sea level monitors including Dart buoys, GPS buoys and tide gauges were used to verify the errors of model data. The simulation results of finite fault models fit the observed records better than uniform slip models as a whole. They have the relatively lower mean absolute/relative error. Fujii's source has the lowest absolute/relative error (0.56 m and 26.71%). UCSB tsunami source also has a better accuracy. At the same time USGSCMT source has the highest precision among three uniform slip models. This paper also suggests that using finite fault models can attain obviously higher precision at tide gauges than uniform slip models with respect to DART buoys and GPS buoys stations, and the errors of tsunami sources have significant orientations. The comparison of tsunami wave spectra was carried out with Fujii's source and UCSB source simulated data. Modeling results from Fujii's source show the better agreement with the spectral energy at wave periods between 12 and 60min than UCSB source. Comparison of tsunami sources inferred from different indirect methods shows the crucial importance of tsunami waveforms for initial seafloor deformation inversion. The joint inversion of tsunami waveform data especially using the deep-ocean tsunami signal can determine the tsunami source quickly and reduce the errors caused by the uncertainty of earthquake rupture processes, which can aid understanding of tsunami generation from earthquakes and nonseismic processes. © 2016, Science Press. All right reserved.


Wang P.-T.,National Marine Environment Forecasting Center | Yu F.-J.,National Marine Environment Forecasting Center | Yu F.-J.,State Oceanic Administration | Zhao L.-D.,National Marine Environment Forecasting Center | And 3 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2012

The Mw=9.0 megathrust earthquake rocked off the northeast coast of Honshu Japan (38.3°N, 142.4°E) on March 11, 2011 at 13:46 Beijing time, which was the most strong earthquake for the past 1200 years in Japan history. A teletsunami was triggered by the huge earthquake and then propagated across the entire Pacific in less than 23 hrs. Tsunami waves were subsequently recorded by a large number of tide gauges throughout the Pacific Ocean and Deep-ocean Assessment and Reporting of Tsunami (DART) buoys in the Pacific Ocean. Tsunami not only caused tremendous damage to the northeast coast of Japan, but also impacted a certain extent of some nations and regions which are located on the east Pacific Coast. The initial tsunami wave arrived in the east coast of Taiwan 4 hours later and the southeast coast of Mainland China about 6~8 hours later. The first Tsunami Warning (Phase: Blue) was issued for the event in China. The aim of the present work is to simulate the tsunami generating, propagating throughout the Pacific Ocean, to attain the tsunami energy spatial distribution in the Pacific region and China offshore. We mainly focus on tsunami wave propagation scenarios around Japan and China coastal areas. The simulation results fit well with the observational data. Impact of this event on China coasts was represented quantitatively based on the simulation results and also evaluation of potential risk from Honshu Japan tsunami was implemented.


Yu F.-J.,National Marine Environment Forecasting Center | Wang P.-T.,National Marine Environment Forecasting Center | Zhao L.-D.,National Marine Environment Forecasting Center | Yuan Y.,National Marine Environment Forecasting Center
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2011

On February 27 2010,06 : 34 UTC, a subduction earthquake of magnitude Mw8. 8 occurred at the southern-central Coastal Chile,generating a tsunami spreading to the entire Pacific Ocean. The epicenter is located at(36. 1°S,72. 6°W). An ocean-wide tsunami was triggered soon after the earthquake, which is recorded by tide gauge networks and Deep-ocean Assessment and Reporting of Tsunami (DART) buoys in the Pacific Ocean. The tsunami leading waves arrived in China coasts 25 hours later. The quantitative analysis of this ocean-wide tsunami was studied in detail with numerical tsunami model in this paper. We mainly focus on tsunami propagation scenarios around Chile and China s coastal areas. The simulation results fit well with the observations. Based on the simulation results, the impact of Chile tsunami on China coasts was discussed quantitatively. The evaluation of potential risk along the China coasts was given.


Xu C.,National Marine Environment Forecasting Center | Yang Q.-H.,National Marine Environment Forecasting Center | Xue Z.-H.,National Marine Environment Forecasting Center
Journal of Natural Disasters | Year: 2011

Based on the observed data from Great Wall Station and NCEP (National Center for Environment Prediction) reanalysis data from 1985 to 2006, the meteorological and hydrological characteristics of sea fog was analyzed and three typical synoptic patterns were found out. Finally a forecast system for sea fog at Great Wall Station in summer was developed and the forecasting experiments show a rather nice result.

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