震后一分钟：强震图,有效震中和有效震级     

T.L.Deng  L.D.Wu  T.C.Shin  Y.B.Tsai  W.H.K.Lee  马维 《世界地震译丛》1998,(5):50-59

本文报道了台湾实时地震监测的最新进展,尤其是台湾中心气象局遥测地震台网(CWBSN)的实时强震监测。该项工作旨在大震发生后迅即速报。如果速报能在强振动到来之前完成,那么地震早期警报将成为可能。CWBSN已能在大震发生后一分钟内给出强度图、震中和震级。速报和早期警报主要适用于大震(M>>5);不限幅波形记录的需要促使CWBSN在1995年将强震探测仪(如力平衡加速度计)并入其遥测地震监测系统中。将时间域递归处理应用于多道输入地震信号,通过一组联网微机生成强度图。通过等值线,能迅速识别出位于强度图最大等值线(通常为100gal)中央的有效震中。有效震级也能迅速由最大等值线(通常为100gal)覆盖的表面积确定。对于具有有限破裂面的大震,如此得出的震中和震级是更适当的震源位置和破坏强度的估算值。有效震中给出了破坏区域的中心,与传统的震中定位比较,后者仅给出了破裂形成的初始位置。有效震级所反映的更接近地震破坏的潜能,而不是强调总能量释放的传统震级。CWBSN已能在一分钟内获取上述震源的关键信息。这一时间将会进一步缩短至30s以内,如本文中举例描述的那样,地震早期警报的确是一个可能达到的目标。速报和早期警报信息将电传给用户,以采取人为或无人干予的快速反应行动。  相似文献   

基于TM图像的塔盆周边地区主要地物亮度值分析   总被引：1，自引：1，他引：1  

阿不都海力力·肉孜  瓦哈甫·哈力克  塔西甫拉提·特依拜 《云南地理环境研究》2006,18(2):6-11

居民点、水体、植被、早地是组成干旱区的主要地物，在遥感图像上反射差异比较大，易于判读；研究这些地物在遥感影像上的亮度值变化规律，对于干旱区遥感监测分析，信息提取过程具有重要意义。利用5景南疆地区5市1县陆地卫星TM影像图，选择出能代表该地区水体、植被、居民地和早地等主要地物的720个样点，分析干旱区4种主要地物在TM影像不同波段上的变化规律以及产生辐射绝对亮度值（R）变化的地物光学性质和状态；揭示干旱区主要地物在TM影像中的亮度值变化的光学特征。研究表明，这种光学特征对水体来说遵循TM1〉TM2〉TM3〉TM4〉TM5〉TM7的规律，对植被来说，遵循TM4〉TM5〉TM1〉TM2〉TM7〉TM3的规律，对居民地来说，遵循TM5〉TM3〉TM1〉TM4〉TM2〉TM7的规律，对早地来说，遵循TM5〉TM3〉TM7〉TM1〉TM4〉TM2的变化规律。  相似文献   

A Diagnostic Study of Moist Potential Vorticity Generation in an Extratropical Cyclone     

Zuohao Cao  G.W.K. Moore Department of Physics  University of Toronto  Toronto  Ontario  Canada  MS A 《大气科学进展》1998,(2)

ＡＤｉａｇｎｏｓｔｉｃＳｔｕｄｙｏｆＭｏｉｓｔＰｏｔｅｎｔｉａｌＶｏｒｔｉｃｉｔｙＧｅｎｅｒａｔｉｏｎｉｎａｎＥｘｔｒａｔｒｏｐｉｃａｌＣｙｃｌｏｎｅ①ＺｕｏｈａｏＣａｏａｎｄＧ．Ｗ．Ｋ．ＭｏｒｅＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ,Ｕｎｉｖｅｒｓ...  相似文献   

德国南部地区Love波相速度分布          下载免费PDF全文

黄忠贤 Fried.  W 《地球物理学报》1998,41(6):788-794

在利用远震面波资料研究小区域内的地壳上地幔速度结构时,传统的面波层析成象所依据的大圆路径和平面波入射假设不能成立．本文利用德国区域地震台网记录的Love波资料,根据Friederich和Wielandt提出的面波波场和速度结构联合反演方法,对德国南部地区的Love波相速度横向不均匀分布作了初步研究．反演得到各个周期面波相速度分布的主要特征是稳定的,不随资料选取而改变．30s左右Love波相速度主要受地壳厚度控制,反演得到的相速度分布与该区域已知的莫霍面深度分布有很好的对应关系．39-66s周期的Love波相速度图像随周期逐渐改变,过渡到一个主要受岩石圈下部上地幔构造活动控制的格局．在75-113s周期范围内的相速度分布图像表明,莱茵地堑等构造活动区为明显的低速区．在研究区域东北部的构造稳定地区,从20-113s周期始终显示为高速区．  相似文献   

A sophisticated lander for scientific exploration of Mars: scientific objectives and implementation of the Mars-96 Small Station     

Linkin V  Harri AM  Lipatov A  Belostotskaja K  Derbunovich B  Ekonomov A  Khloustova L  Kremnev R  Makarov V  Martinov B  Nenarokov D  Prostov M  Pustovalov A  Shustko G  Jarvinen I  Kivilinna H  Korpela S  Kumpulainen K  Lehto A  Pellinen R  Pirjola R  Riihela P  Salminen A  Schmidt W  McKay CP 《Planetary and Space Science》1998,46(6-7):717-737

A mission to Mars including two Small Stations, two Penetrators and an Orbiter was launched at Baikonur, Kazakhstan, on 16 November 1996. This was called the Mars-96 mission. The Small Stations were expected to land in September 1997 (Ls approximately 178 degrees), nominally to Amazonis-Arcadia region on locations (33 N, 169.4 W) and (37.6 N, 161.9 W). The fourth stage of the Mars-96 launcher malfunctioned and hence the mission was lost. However, the state of the art concept of the Small Station can be applied to future Martian lander missions. Also, from the manufacturing and performance point of view, the Mars-96 Small Station could be built as such at low cost, and be fairly easily accommodated on almost any forthcoming Martian mission. This is primarily due to the very simple interface between the Small Station and the spacecraft. The Small Station is a sophisticated piece of equipment. With the total available power of approximately 400 mW the Station successfully supports an ambitious scientific program. The Station accommodates a panoramic camera, an alpha-proton-x-ray spectrometer, a seismometer, a magnetometer, an oxidant instrument, equipment for meteorological observations, and sensors for atmospheric measurement during the descent phase, including images taken by a descent phase camera. The total mass of the Small Station with payload on the Martian surface, including the airbags, is only 32 kg. Lander observations on the surface of Mars combined with data from Orbiter instruments will shed light on the contemporary Mars and its evolution. As in the Mars-96 mission, specific science goals could be exploration of the interior and surface of Mars, investigation of the structure and dynamics of the atmosphere, the role of water and other materials containing volatiles and in situ studies of the atmospheric boundary layer processes. To achieve the scientific goals of the mission the lander should carry a versatile set of instruments. The Small Station accommodates devices for atmospheric measurements, geophysical and geochemical studies of the Martian surface and interior, and cameras for descent phase and panoramic views. These instruments would be able to contribute remarkably to the process of solving some of the scientific puzzles of Mars.  相似文献   

The population composition of Brunei     

Neville W 《Singapore journal of tropical geography》1990,10(1):27-42

Population characteristics of Brunei are examined, including ethnic composition, age and sex distribution, labor force participation, and occupational status. The author relates the population structure to the economic conditions in Brunei and discusses future implications for economic and social policy.  相似文献   

Evidence for methane and ammonia in the coma of comet P/Halley     

Allen M  Delitsky M  Huntress W  Yung Y  Ip WH  Schwenn R  Rosenbauer H  Shelley E  Balsiger H  Geiss J 《Astronomy and Astrophysics》1987,187(1-2):502-512

Methane and ammonia abundances in the coma of Halley are derived from Giotto IMS data using an Eulerian model of chemical and physical processes inside the contact surface to simulate Giotto HIS ion mass spectral data for mass-to-charge ratios (m/q) from 15 to 19. The ratio m/q = 19/18 as a function of distance from the nucleus is not reproduced by a model for a pure water coma. It is necessary to include the presence of NH3, and uniquely NH3, in coma gases in order to explain the data. A ratio of production rates Q(NH3)/Q(H2O) = 0.01-0.02 results in model values approximating the Giotto data. Methane is identified as the most probable source of the distinct peak at m/q = 15. The observations are fit best with Q(CH4)/Q(H2O) = 0.02. The chemical composition of the comet nucleus implied by these production rate ratios is unlike that of the outer planets. On the other hand, there are also significant differences from observations of gas phase interstellar material.  相似文献   

1991-2020年新疆降水的时空变化特征     

李晔曼吾拉·卡德尔 《广东气象》2022,(3):42-45

利用新疆35个观测站1991—2020年逐日降水量资料,采用降水变差系数、线性趋势分析、Morlet小波分析等方法研究了新疆天山南、北坡与山区的降水时空变化特征。结果表明:新疆降水量空间分布差异大,从北向南减少的梯度明显且西部多于东部。夏季降水量占全年降水量45%,山区降水量相对稳定,北坡降水四季分布更均衡,南坡降水量主要在夏、春两季。近30年降水量总体呈显著增加趋势,而且秋季降水量增加更明显,降水量具有准10和准20年的周期。  相似文献   

Crabs,leeches and trypanosomes: an unholy trinity?     

Hemmingsen W  Jansen PA  Mackenzie K 《Marine pollution bulletin》2005,50(3):336-339

The red king crab Paralithodes camtschaticus was deliberately introduced to the Barents Sea in the 1960s and 1970s from its native area in the North Pacific. The carapace of these crabs is a favoured substrate for the leech Johanssonia arctica to deposit its eggs, and the leech is a vector for a trypanosome blood parasite of marine fish, including cod. We examined cod for trypanosome infections during annual cruises along the coast of Finnmark in North Norway over three successive years from stations along a gradient of over 1000 km. In every year the level of trypanosome infection in cod was significantly highest in the area with the greatest density of king crabs. We propose the hypothesis that the burgeoning population of red king crabs in this area is indirectly responsible for increased transmission of trypanosomes to cod by promoting an increase in the population of the leech vector.  相似文献   

Water quality assessment for sustainable agriculture in the Wet Tropics--a community-assisted approach     

Faithful J  Finlayson W 《Marine pollution bulletin》2005,51(1-4):99-112

A number of studies in north Queensland over the past two decades have concluded that large amounts of nutrients and sediments are exported from agricultural watersheds, particularly during wet season rainfall events. With the co-operation of a number of growers, runoff from Queensland Wet Tropics banana and cane farm paddocks in two distinct tropical river catchments was examined to provide an estimate of nutrient and sediment concentrations and export, with comparison to water quality of flow through a small urban lakes system. Median total nitrogen concentrations in cane drainage runoff (3110 microg N/L) were higher than for banana paddock drainage (2580 microg N/L), although the maximum concentration was recorded from a banana paddock (20,900 microg N/L). Nitrogen losses during post-event drainage flow were supplemented by high proportions of NO(X) (nitrate + nitrite) sourced from groundwater inputs. Banana paddocks had the highest maximum and median total phosphorus and TSS concentrations (5120 and 286 microg P/L, and 7250 and 75 mg/L respectively) compared to the cane farms (1430 and 50 microg P/L, and 1840 and 14 mg/L respectively). The higher phosphorus and TSS concentrations in the banana runoff were attributed to higher paddock slopes and a greater proportion of exposed ground surface during the wet season. Highest nutrient and TSS concentrations corresponded with samples collected near the peak discharge periods; however, the rising stage of the drainage flows, where the highest nutrient and TSS concentrations are often reported, were difficult to target because of the manual sampling strategy used. This study shows that high concentrations of nutrients and TSS occur in the runoff from cane and banana paddocks. Median total nitrogen, total phosphorus and TSS concentrations in flow through the urban lakes were 369 microg N/L, 16 microg P/L and 11 mg/L, respectively. Flux estimates of 9.2 kg N, 0.8 kg P and 126 kg TSS/ha were determined for drainage runoff from a banana paddock during a single intensive storm event.  相似文献