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81.
Eddy Shedding from the Kuroshio Bend at Luzon Strait 总被引:16,自引:1,他引:16
TOPEX/POSEDIENT-ERS satellite altimeter data along with the mean state from the Parallel Ocean Climate Model result have been used to investigate the variation of Kuroshio intrusion and eddy shedding at Luzon Strait during 1992–2001. The Kuroshio penetrates into the South China Sea and forms a bend. The Kuroshio bend varies with time, periodically shedding anticyclonic eddies. Criteria of eddy shedding are identified: 1) When the shedding event occurs, there are usually two centers of high Sea Surface Height (SSH) together with negative geostrophic vorticity in the Kuroshio Bend (KB) area. 2) Between the two centers of high SSH there usually exists positive geostrophic vorticity. These criteria have been used to determine the eddy shedding times and locations. The most frequent eddy shedding intervals are 70, 80 and 90 days. In both the winter and summer monsoon period, the most frequent locations are 119.5°E and 120°E, which means that the seasonal variation of eddy shedding location is unclear. 相似文献
82.
Whether or not there are extensional detachment faults in the Alboran basement can be tested directly because a part of the Alboran Basin is now emerged. These detachments, related to crustal thinning beneath the Alboran Basin, occurred from the Aquitanian to Tortonian. The resulting extensional geometries can be described in general terms. During the Serravalian a considerable southwest extension of the basin took place, accompanied by south-southeast extension in the northern Gibraltar Arc. Other detachments affected by Serravalian extension can be found. The spreading of the Alboran was nearly coeval with roughly westward migration of the Gibraltar mountain front. 相似文献
83.
In this paper we analyze seismic regime and earthquake depth distribution and correlation of seismicity and mud volcanism in the Azerbaijan and the Caspian Sea region. For the present region we have calculated accurate source locations, seismic activity, earthquake repetition and released earthquake energy parameters. It is shown that the active tectonic processes in the region are concentrated within the thick sedimentary cover that we consider as a general source of contemporary stress and a main structural element responsible for the origin of regional earthquakes. The correlation of seismicity and mud volcanism is of paragenetic character. 相似文献
84.
The underwater acoustic image transmission system based on the high-speed DSP device TMS320C549 has been studied.We use Goertzel algorithm for source decoding and MFSK for modulation.Turbo code is used for channel coding and decoding.The purpose is to implement underwater video image data transmission. 相似文献
85.
最近,由欧盟(则资助的研究项目(Parforce)研究人员发现了海洋藻类与气候变化之间的联系。项目研究人员发现,从海洋藻类及浮游生物释放的碘蒸汽,在海面上浓缩,形成对抗地球变暖的悬浮微粒。此悬浮微粒对地球气候变化及降 相似文献
86.
Participatory fisheries management has been increasingly proposed as a useful management approach to address fisheries problems. However, the criteria regarding its applicability and measures of success still seem unclear. This study reviews the main concepts and theory behind two participatory resource-management approaches and compares them to the reality of fisheries management in Costa Rica. The analysis shows that while the implementation of a participatory approach in fisheries management should be encouraged, it is essential to keep in mind the possible limitations these approaches have. Furthermore, it seems important to improve institutional coordination and develop social, legal and economic policies that will allow the state, together with coastal communities, to contribute in an effective way to fisheries management. 相似文献
87.
88.
Knowledge of marine geological environments in which shallow gas is accumulating is becoming increasingly important in global
studies of climate change because a measurable proportion of the total methane source comes from continental margins. Previous
studies have revealed that coastal environments represent important geological environments where microbial methane is being
generated, is accumulating, and is being released. In the Ría de Pontevedra, at least 4.5 km2 of seafloor in the innermost part of the ría is underlain by sediments containing natural gas. Seismic interpretation contributes
new findings for the definition of periods and geological environments in which the gas could have been generated, and is
accumulating and released in the Ría de Pontevedra. Groundtruthing the seismic data (facies, environments) makes it possible
to identify favourable geological environments for gas generation in the sedimentary infill of the Ría de Pontevedra. Sequence
stratigraphy based on high-resolution seismic profiles and post-Last Glacial Maximum sea-level records makes it possible to
establish the stratigraphic architecture of the ría and to define the periods in which gas could have been generated. The
results of this study show that the sedimentary infill is composed of a fifth-order sequence developed since the Last Glacial
Maximum. Within this sequence, gas appears to have accumulated in the Holocene deposits associated with the latest transgressive
and highstand system tracts. Seismic analysis shows that gas could have been generated in different geological environments
in the Ría de Pontevedra. If coastal environments at times of lower sea level were similar to those of the present, organic-rich
mud deposits (deposited mainly in lakes, estuaries and floodplains) could have survived transgression and remained buried
as potential gas sources in the inner part of the ría. 相似文献
89.
A comparative analysis of spotless and spot group flares recorded at Hvar and Kanzelhöhe Observatories during the 21st cycle of solar activity is presented. The rate of occurrence of two-ribbon flares was found to be significantly higher for the spotless flares. In comparison with spot group flares of corresponding H importance, the soft X-ray peak values have been systematically lower for the spotless flares. The highest peak values and the energy released in soft X-rays was found for flares with a H ribbon protruding over a major spot umbra. It was found that the effective plasma temperatures in spotless flares have been considerably lower than the temperatures in spot group flares. 相似文献
90.
Spin rate estimation of sounding rockets using GPS wind-up 总被引:2,自引:1,他引:1
Carrier phase wind-up is a well-known effect that arises from the relative rotation between a transmitting and receiving antenna.
In GPS measurements at L1 frequency, this effect translates into an error of 19.029 cm per full relative rotation of antennas.
Since this effect is independent of the satellite elevation for pure rotation about the antenna boresight axis, it is usually
absorbed by the clock estimation in navigation algorithms. Therefore, the impact of wind-up is usually neglected for applications
that do not require accuracies to the cm level like RTK. However, in receiving platforms with high rotation rate, the accumulated
wind-up value can be important and actually be larger than receiver noise or even ionospheric variations. Therefore, in such
scenarios, the wind-up contribution can be isolated and used as a source of information to compute the spin rate of such platforms
using an appropriate combination of GPS observables. This work shows some results of a coarse, yet simple, approach to monitor
the rotation angle and spin-rate of spin stabilized sounding rockets flown by DLR. 相似文献