Tan M.,CAS Institute of Geology and Geophysics
Climate Dynamics | Year: 2014
Inter-annual variation in the ratio of 18O to 16O of precipitation (δ18Op) in the monsoon regions of China (MRC, area approximately east of 100°E) has not yet been fully analyzed. Based on an analysis of the relationships between the time series of amount-weighted mean annual δ18O in precipitation (δ18Ow) and meteorological variables such as temperature, precipitation as well as atmospheric/oceanic circulation indices, it is recognized that the El Niño-Southern Oscillation (ENSO) cycle appears to be the dominant control on the inter-annual variation in δ18Op in the MRC. Further analysis shows that the trade wind plays a role in governing δ18Ow through affecting the intensity of the different summer monsoon circulations which are closely linked to the weakening (weaker than normal) and strengthening (stronger than normal) of the trade wind and gives the δ18Ow different values at or over inter-annual timescales. The southwest monsoon (SWM) drives long-distance transport of water vapor from Indian Ocean to the MRC, and along this pathway increasing rainout leads to more negative δ18Ow via Rayleigh distillation processes. In contrast, the southeast monsoon (SEM), which is consistent with the changes in the strength of the West Pacific subtropical high, drives short-distance water vapor transport from the West Pacific Ocean to the MRC and leads to less negative δ18Ow. Therefore, the δ18Ow value directly reflects the differences in influence between the SWM, which is strong when the SE trade wind is strong, and the SEM, which is strong when the SE trade wind is weak. In addition, the South China Sea Monsoon also transports local water vapor as well as plays a role in achieving the synchronization between the δ18Ow and ENSO. The author thus terms the δ18Op rhythm in the MRC the "circulation effect". In turn, the δ18Op variation in the MRC has the potential to provide information on atmospheric circulation and the signal of δ18Op recorded in natural archives can then be used to deduce a long-term behavior of the tropical climate system. © 2013 Springer-Verlag Berlin Heidelberg. Source
CAS Institute of Geology and Geophysics | Date: 2015-07-14
A symmetrical MEMS accelerometer. The accelerometer includes a top half and a bottom half bonded together to form the frame and the mass located within the frame. The frame and the mass are connected through resilient beams. A plurality of hollowed parts and the first connecting parts are formed on the top and bottom side of the mass, respectively. The second connecting parts are formed on the top and bottom side of the frame, respectively. The resilient beams connect the first connecting part with the second connecting part. Several groups of comb structures are formed on top of the hollowed parts. Each comb structure includes a plurality of moveable teeth and fixed teeth. The moveable teeth extend from the first connecting part and the fixed teeth extend from the second connecting part. Capacitance is formed between the movable teeth and the fixed teeth. Since the accelerometer is symmetrical with a large mass, it has a large capacitance with a low damping force.
CAS Institute of Geology and Geophysics | Date: 2012-11-05
It is provided a method and a device for acquiring optimization coefficients, and a related method and device for simulating a wave field. Determining whether the values of a discrete variable K
CAS Institute of Geology and Geophysics | Date: 2012-06-15
A million channel-class digital seismometer based on a computer network, the hardware thereof consisting of seven major units: a central control operating system (CCOS), a root unit (RU), a network unit (NU), a power unit (PU), an acquisition link (AS), a fiber line (FL), and a network line (NL); wherein the CCOS is a control center and a data retrieving center for the entire instrument, the RU is a connection interface between the COOS and a field device; a plurality of NUs are serially connected via the FL to form a network unit link NUS, and the RU is connected to one or more NUS; the PU and the AS are randomly and serially connected to form an acquisition line (AL), and any PU on the AL is connected to the NU via a 100-Mbit/s NL.
CAS Institute of Geology and Geophysics | Date: 2013-09-19
An accelerometer has E-shaped resilient beams to isolate stress and reduce deformation. A top cap silicon wafer and a bottom cap silicon wafer are both coupled with a measurement mass to form a capacitor. The measurement mass has a mass, range-of-motion stops, and resilient beams located within a support frame. The range-of-motion stops are coupled to the support frame by connection beams, and the mass is coupled with the range-of-motion stops by groups of E-shaped resilient beams. The ends of each resilient beam are connected to the range-of-motion stops, and the middle of each resilient beam is connected to the mass.