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Huang N.E.,National Central University | Chen X.,First Institute of Oceanography | Lo M.-T.,National Central University | Wu Z.,Florida State University
Advances in Adaptive Data Analysis | Year: 2011

As the original definition on Hilbert spectrum was given in terms of total energy and amplitude, there is a mismatch between the Hilbert spectrum and the traditional Fourier spectrum, which is defined in terms of energy density. Rigorous definitions of Hilbert energy and amplitude spectra are given in terms of energy and amplitude density in the time-frequency space. Unlike Fourier spectral analysis, where the resolution is fixed once the data length and sampling rate is given, the time-frequency resolution could be arbitrarily assigned in Hilbert spectral analysis (HSA). Furthermore, HSA could also provide zooming ability for detailed examination of the data in a specific frequency range with all the resolution power. These complications have made the conversion between Hilbert and Fourier spectral results difficult and the conversion formula is elusive until now. We have derived a simple relationship between them in this paper. The conversion factor turns out to be simply the sampling rate for the full resolution cases. In case of zooming, there is another additional multiplicative factor. The conversion factors have been tested in various cases including white noise, delta function, and signals from natural phenomena. With the introduction of this conversion, we can compare HSA and Fourier spectral analysis results quantitatively. © 2011 World Scientific Publishing Company.

Lu C.-H.,Fuzhou University | Zhu C.-L.,First Institute of Oceanography | Li J.,Fuzhou University | Liu J.-J.,Fuzhou University | And 3 more authors.
Chemical Communications | Year: 2010

We have proved that functionalized nanoscale graphene oxide can protect oligonucleotides from enzymatic cleavage and efficiently deliver oligonucleotides into cells. © The Royal Society of Chemistry 2010.

Li Z.,First Institute of Oceanography | Yu W.,First Institute of Oceanography | Li T.,University of Hawaii at Manoa | Murty V.S.N.,National Institute of Oceanography of India | Tangang F.,National University of Malaysia
Journal of Climate | Year: 2013

The annual cycle of tropical cyclone (TC) frequency over the Bay of Bengal (BoB) exhibits a notable bimodal character, different from a single peak in other basins. The causes of this peculiar feature were investigated through the diagnosis of a genesis potential index (GPI) with the use of the NCEP Reanalysis I dataset during the period 1981-2009. A methodology was developed to quantitatively assess the relative contributions of four environmental parameters. Different from a conventional view that the seasonal change of vertical shear causes the bimodal feature, it was found that the strengthened vertical shear alone from boreal spring to summer cannot overcome the relative humidity effect. It is the combined effect of vertical shear, vorticity, and SST that leads to the GPI minimum in boreal summer. It is noted that TC frequency in October-November is higher than that in April-May, which is primarily attributed to the difference of mean relative humidity between the two periods. In contrast, more supercyclones (category 4 or above) occur in April-May than in October-November. It is argued that greater ocean heat content, the first branch of northward-propagating intraseasonal oscillations (ISOs) associated with the monsoon onset over the BoB, and stronger ISO intensity in April-May are favorable environmental conditions for cyclone intensification. © 2013 American Meteorological Society.

Zhu C.-L.,First Institute of Oceanography | Lu C.-H.,Fuzhou University | Song X.-Y.,First Institute of Oceanography | Yang H.-H.,Fuzhou University | Wang X.-R.,First Institute of Oceanography
Journal of the American Chemical Society | Year: 2011

This communication describes the design of a novel and general bioresponsive controlled-release mesoporous silica (MS) nanoparticles system based on aptamer-target interactions. In this system, the pores of MS were capped with Au nanoparticles modified with aptamer (ATP aptamer in this case). By a competitive displacement reaction, the Au nanoparticles were uncapped in the presence of ATP molecule, and the cargo was released. Our results demonstrated that the aptamer-target interaction may be a promising route for the design of custom-made controlled-release nanodevices specifically governed by target biomolecules. Since aptamers have been obtained for a broad range of targets, including several cancer biomarkers, we believe that this aptamer-based controlled-release system should have an equally broad spectrum of applications. © 2011 American Chemical Society.

Carollo C.,First Institute of Oceanography | Reed D.J.,First Institute of Oceanography
Marine Policy | Year: 2010

We present a case study of the organizational framework of the Gulf of Mexico Alliance (GOMA), which was implemented to promote the use of ecosystem-based management (EBM) at a regional level. GOMA is a state-led initiative formed to protect and restore coastal and marine resources of the Gulf of Mexico. Representatives of the US Gulf States, together with their federal partners, clearly defined ecological, social, and economic short- and long-term objectives to be reached through regional collaborations. The aim of this paper is to show how GOMA, and particularly the Ecosystem Integration and Assessment Priority Issue Team, in its attempt to apply ecosystem approaches to manage marine resources, modified the common organizational scheme by implementing partnerships at various governmental (federal, state, local) and nongovernmental levels. We address the following major points considered to be of importance for EBM implementation: (1) multilevel cooperation, (2) stakeholders' involvement, (3) sharing of information, (4) bridging science and policy, and (5) consensus-based decision making. © 2009 Elsevier Ltd. All rights reserved.

Song Z.,Ocean University of China | Song Z.,First Institute of Oceanography | Qiao F.,First Institute of Oceanography | Song Y.,First Institute of Oceanography
Journal of Geophysical Research: Oceans | Year: 2012

[1] One of the common problems of the coupled atmosphere-ocean general circulation models (AOGCMs) without flux correction is that the simulated sea surface temperature (SST) deviates noticeably from the observation especially in the tropics, such as the too cold tongue in the eastern Pacific and a reversed SST zonal gradient in the equatorial Atlantic. The coupled atmosphere-wave-ocean general circulation model, which incorporates the non-breaking surface wave-induced mixing into the CCSM3 through a coupler, can improve the simulation of the tropical SST. On the ocean-basin scale, the wave-induced vertical mixing can generate "West-Positive and East-Negative" pattern for the equatorial SST that much alleviates the tropical bias. The formation mechanism for this basin-wide response to the wave-induced mixing is analyzed through sensitive experiments of AOGCMs and stand-alone ocean general circulation models (OGCMs). First, in each basin, the SST becomes colder under the direct effect of the wave-induced mixing, and the SST in the eastern part of each basin is colder due to the shallower ocean mixed layer than that of the western part. The SST in the western basin (or central basin in the Pacific Ocean) increases due to the weakened eastward zonal current. Then, the pattern of warm SST in the west and cold SST in the east is amplified due to the Bjernkes feedback in a climate system. The net heat flux feedback plays a negative role in this kind of SST response. © 2012. American Geophysical Union. All Rights Reserved.

Yuan Y.,First Institute of Oceanography | Huang N.E.,First Institute of Oceanography | Huang N.E.,Research Center for Adaptive Data Analysis
Journal of Geophysical Research: Oceans | Year: 2012

A reappraisal of wave theory from the beginning to the present day is made here. On the surface, the great progress in both theory and applications seems to be so successful that there would be no great challenge in wave studies anymore. On deeper examination, we found problems in many aspects of wave studies starting from the definition of frequency, the governing equations, the various source functions of wave models, the directional development of wind wavefield, the wave spectral form and finally the role of waves as they affect coastal and global ocean dynamics. This is a call for action for the wave research community. For future research, we have to consider these problems seriously and also to examine the basic physics of wave motion to determine their effects on other ocean dynamic processes quantitatively, rather than relying on parameterization in oceanic and geophysical applications. © 2012. American Geophysical Union. All Rights Reserved.

Zheng X.-T.,Ocean University of China | Xie S.-P.,Ocean University of China | Xie S.-P.,University of Hawaii at Manoa | Xie S.-P.,University of California at San Diego | And 4 more authors.
Journal of Climate | Year: 2013

The response of the Indian Ocean dipole (IOD) mode to global warming is investigated based on simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5). In response to increased greenhouse gases, an IOD-like warming pattern appears in the equatorial Indian Ocean, with reduced (enhanced) warming in the east (west), an easterly wind trend, and thermocline shoaling in the east. Despite a shoaling thermocline and strengthened thermocline feedback in the eastern equatorial Indian Ocean, the interannual variance of the IOD mode remains largely unchanged in sea surface temperature (SST) as atmospheric feedback and zonal wind variance weaken under global warming. The negative skewness in eastern Indian Ocean SST is reduced as a result of the shoaling thermocline. The change in interannual IOD variance exhibits some variability among models, and this intermodel variability is correlated with the change in thermocline feedback. The results herein illustrate that mean state changes modulate interannual modes, and suggest that recent changes in the IOD mode are likely due to natural variations. © 2013 American Meteorological Society.

Qing S.,Inner Mongolia Normal University | Zhang J.,First Institute of Oceanography | Cui T.,First Institute of Oceanography | Bao Y.,Inner Mongolia Normal University
Remote Sensing of Environment | Year: 2013

A simple multi-linear regression model was developed for sea surface salinity, and tested against in situ measurements. The algorithm can be applied to in situ measured reflectance data with a root mean square error of 0.833psu (R2=0.64). The model was recalibrated based on remote sensing reflectance data derived from MERIS and from in situ salinity data, yielding a RMSE in modeled salinity (relative to in situ data) of 1.311psu. This recalibrated model can be applied to MODIS data following a linear correction. The spatio-temporal changes in sea surface salinity and in the influence of freshwater flow were analyzed using MERIS, MODIS and river discharge data. Sea surface salinity in Laizhou Bay, Bohai Bay and Liaodong Bay was fresher than that in Qinhuangdao, the central Bohai Sea and Bohai Strait. During 2004-2009, the temporal trends in sea surface salinity varied between sites. Salinity in most parts of the Bohai Sea was increasing. The Yellow River discharge was found to have the greatest influence on sea surface salinity near the river estuary, whereas it had only a weak impact on the salinity far from river mouth. More independent datasets are needed to improve the model and to gain a better understanding of processes controlling changes in sea surface salinity. © 2013 Elsevier Inc.

Chiang J.C.H.,University of California at Berkeley | Fang Y.,University of California at Berkeley | Fang Y.,First Institute of Oceanography
Journal of Climate | Year: 2010

Model evidence is presented to make the case that the midlatitude North Pacific wintertime transient eddy activity may have been significantly weaker during the mid-Holocene (~6000 yr BP). A simulation of the midHolocene climate in an atmospheric general circulation model coupled to a reduced gravity ocean model showed significant reduction to transient eddy activity, up to 30% in the main storm-track region. The reduced baroclinic eddy activity is associated with basinwide climate changes over the northern and tropical Pacific, including a deepening of the Aleutian low, colder SSTs in the western and central North Pacific, a strengthening and southward shift of the subtropical jet, and a strengthened South Pacific convergence zone. These associated climate changes are consistently simulated across a range of Paleoclimate Modeling Inter comparison Project Phase II (PMIP2) coupled models forced with mid-Holocene climate forcings, suggesting they are a robust response to mid-Holocene orbital forcing. The authors link the mid-Holocene climate changes to two related modern-day analogs: (i) interannual variations in wintertime North Pacific storminess and (ii) the phenomenon of midwinter suppression whereby North Pacific transient eddy activity in today's climate is reduced in midwinter. In both instances, the associated North Pacific climate conditions resemble those seen in the mid-Holocene simulations. While it remains to be seen which analog is dynamically more appropriate, the latter link-midwinter suppression-offers the simple physical interpretation that the mid Holocene reduction in storminess is a consequence of a "more winterlike" climate resulting from the mid Holocene precessional forcing. © 2010 American Meteorological Society.

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