机载微波辐射计测云中液态水含量 (I):仪器和标定   总被引：1，自引：0，他引：1  

雷恒池  魏重  沈志来  张晓庆  金德镇  谷淑芳  李茂伦  张景红 《高原气象》2003,(6)

简要介绍为研制机载对空测云微波辐射计所做的预研究,结果确认了研制这样的单频机载微波辐射计的可行性,并明确了仪器的技术难点,给出了针对技术难点提出的设计方案和技术指标。本文还介绍了对仪器进行灵敏度测试的实验方法和结果。实验室测试和晴空飞行测试表明,在一定的条件下,仪器灵敏度指标达到0.2K;还较详细地介绍了几种实用的标定方法,并讨论了它们的适用范围和不确定性。  相似文献   

遥感影像定标最佳样区的自动搜索方法     

沈焕锋  李平湘  汪志明 《测绘信息与工程》2004,29(3):32-34

提出了在遥感影像定标过程中自动搜索样区的算法,以窗口内像元灰度值的标准差作为衡量该窗口内像元灰度均匀性的测度,并以此确定用于定标的最佳样区,实验验证了其实效性.  相似文献   

Calibration of GOCE SGG data using high–low SST, terrestrial gravity data and global gravity field models     

J. Bouman  R. Koop  C. C. Tscherning  P. Visser 《Journal of Geodesy》2004,78(1-2):124-137

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荣成市石岛湾镆鎁岛港的潮汐     

蓝淑芳  丁宗信 《海洋科学》1995,19(3):55-59

１９９２年６～７月，中国科学院海洋研究所在镆岛港建立临时验潮站。计 算得到该港调和常数及潮位特征值。分析表明，镆　岛港属于非正规半日潮港。根 据镆岛港和同期及３年石岛港测得资料（二港符合潮汐相似性条件）进行相关分 析和统计计算，获得镆　岛港的设计水位和校核水位等。  相似文献   

Revised ΔR values for the Barents Sea and its archipelagos as a pre-requisite for accurate and robust marine-based 14C chronologies     

《Quaternary Geochronology》2022

The calibration of marine ¹⁴C dates requires the incorporation of regionally specific marine reservoir offsets known as ΔR, essential for accurate and meaningful inter-archive comparisons. Revised, regional ΔR (‘ΔR_R’) values for the Barents Sea are presented for molluscs and cetaceans for the two latest iterations of the marine calibration curve, based on previously published pre-bomb live-collected and radiocarbon-dated samples (‘ΔR_L’; molluscs: n = 16; cetaceans: n = 18). Molluscan ΔR_R, determined for four broad regional oceanographic settings, are: western Svalbard (including Bjørnøya), −61 ± 37 ¹⁴C yrs (Marine20), 94 ± 38 ¹⁴C yrs (Marine13); Franz Josef Land, −277 ± 57 ¹⁴C yrs (Marine20), −122 ± 38 ¹⁴C yrs (Marine13); Novaya Zemlya, −156 ± 73 ¹⁴C yrs (Marine20), 0 ± 76 ¹⁴C yrs (Marine13); northern Norway, −86 ± 39 ¹⁴C yrs (Marine20), 74 ± 24 ¹⁴C yrs (Marine13). Molluscan ΔR_R values are considered applicable to other marine carbonate materials (e.g., foraminifera, ostracods). Cetacean ΔR_R are determined for toothed (n = 10) and baleen (n = 8) whales, and a combined toothed-baleen group (n = 18): toothed, −161 ± 41 ¹⁴C yrs (Marine20), 1 ± 41 ¹⁴C yrs (Marine13); baleen, −158 ± 43 ¹⁴C yrs (Marine20), 8 ± 41 ¹⁴C yrs (Marine13); combined baleen-toothed whales, −160 ± 41 ¹⁴C yrs (Marine20), 4 ± 49 ¹⁴C yrs (Marine13). Where identification and separation of baleen and toothed whales is impossible the combined ΔR_R term may be used. However, we explicitly discourage the application of existing cetacean ΔR_R terms to other marine mammals. Our new ΔR_R values are applicable for as long as those broad oceanographic conditions (circulation and ventilation) have persisted, i.e., through the Holocene. We recommend using the latest iteration of the marine calibration curve, Marine20, which seems to better capture the time-variant nature of R compared to Marine13. More ΔR_L datapoints for both molluscs and cetaceans would improve the accuracy and precision of ΔR_R. In the meantime, our new ΔR terms facilitate the calibration of marine ¹⁴C dates across the region, paving the way for meaningful and accurate late Quaternary histories and inter-regional comparisons.  相似文献   

甘肃地区近震震级的量规函数研究     

陈继锋  尹欣欣  董宗明  姚海东  蒲举 《中国地震研究》2014,28(3):370-379

To calculate the deviations between single station magnitudes and average ones by the magnitude residual statistical method, the paper selects 13086 seismic events recorded by the Gansu broadband digital seismic network from January 2009 to December 2012. The frequency distribution and quantitative statistics of the deviations of earthquake magnitude are analyzed. The M L calibration function is modified and a uniform local magnitude system characteristic of the Gansu region, is obtained.  相似文献   

用多通道AD分级采集扩展地震数据采集器的动态范围   总被引：2，自引：1，他引：1       下载免费PDF全文

滕云田  胡星星  王喜珍  王晓美  卢红娅  王喆  张旸 《地球物理学报》2016,59(4):1435-1445

地震数据采集是地震信号数字化必不可少的环节,动态范围是其一个重要的性能指标.实际地震信号的动态范围在160dB以上,而目前普遍使用的24位地震数据采集器动态范围相对较小且在50 Hz采样率时最大只达到135dB,致使24位地震数据采集器在实际使用中对小信号分辨率不够,不能有效提取地震信息;在大地震时又容易使数据采集器出现饱和限幅失真的现象而失去地震监测记录功能.本文针对在地震监测和地震研究中需要具有高分辨率和高动态范围的地震数据采集器这个亟待解决的问题,提出一种采用多通道AD转换器并行分级采集的方法,讨论了通道间失配及其标定.对研制实验样机的测试表明,其动态范围在50Hz采样时可以达到157dB以上,线性度优于0.005%.  相似文献   

Geological calibration of spallation production rates in the CRONUS-Earth project     

《Quaternary Geochronology》2016

Models of the production of cosmogenic nuclides typically incorporate an adjustable production rate parameter that is scaled for variations in production with latitude and altitude. In practice, this production rate parameter is set by calibration of the model using cosmogenic nuclide data from sites with independent age constraints. In this paper, we describe a calibration procedure developed during the Cosmic-Ray Produced Nuclide Systematics on Earth (CRONUS-Earth) project and its application to an extensive data set that included both new CRONUS-Earth samples and samples from previously published studies. We considered seven frameworks for elevation and latitude scaling and five commonly used cosmogenic nuclides, ³He, ¹⁰Be, ¹⁴C, ²⁶Al, and ³⁶Cl. In general, the results show that the calibrated production rates fail statistical tests of goodness-of-fit. One conclusion from the calibration results is that two newly developed scaling frameworks and the widely used Lal scaling framework provide qualitatively similar fits to the data, while neutron-monitor based scaling frameworks have much poorer fit to the data. To further test the fitted models, we computed site ages for a number of secondary sites not included in the primary calibration data set. The root-mean-square percent differences between the median computed ages for these secondary sites and independent ages range from 7.1% to 27.1%, differences that are much larger than the typical uncertainties in the site ages. The results indicate that there are substantial unresolved difficulties in modeling cosmogenic nuclide production and the calibration of production rates.  相似文献   

四分量钻孔应变观测的实地绝对标定   总被引：17，自引：1，他引：16  

邱泽华  石耀霖  欧阳祖熙 《地震》2005,25(3):27-34

钻孔应变观测的实地标定问题有二层涵义: 在第一个层面上, 可以认为实地标定是相对室内标定而言的, 是对仪器(元件)灵敏度的标定, 称为相对标定; 在第二个层面上, 由测值换算出孔径相对变化以后, 还要利用理论固体潮等依据对与钻孔周围介质的弹性有关的参数进行标定, 从而给出应变变化, 称为绝对标定。 文中提出了四分量钻孔应变观测的绝对标定的新方法, 并以昌平台RZB-1型钻孔应变观测为例进行实际应用, 取得了相当好的结果。  相似文献   

LIDAR strip adjustment: Application to volcanic areas     

Massimiliano Favalli  Alessandro Fornaciai  Maria Teresa Pareschi 《Geomorphology》2009,111(3-4):123-135

DEMs derived from LIDAR data are nowadays largely used for quantitative analyses and modelling in geology and geomorphology. High-quality DEMs are required for the accurate morphometric and volumetric measurement of land features. We propose a rigorous automatic algorithm for correcting systematic errors in LIDAR data in order to assess sub-metric variations in surface morphology over wide areas, such as those associated with landslide, slump, and volcanic deposits. Our procedure does not require a priori knowledge of the surface, such as the presence of known ground control points. Systematic errors are detected on the basis of distortions in the areas of overlap among different strips. Discrepancies between overlapping strips are assessed at a number of chosen computational tie points. At each tie point a local surface is constructed for each strip containing the point. Displacements between different strips are then calculated at each tie point, and minimization of these discrepancies allows the identification of major systematic errors. These errors are identified as a function of the variables that describe the data acquisition system. Significant errors mainly caused by a non-constant misestimation of the roll angle are highlighted and corrected. Comparison of DEMs constructed using first uncorrected and then corrected LIDAR data from different Mt. Etna surveys shows a meaningful improvement in quality: most of the systematic errors are removed and the accuracy of morphometric and volumetric measurements of volcanic features increases. These corrections are particularly important for the following studies of Mt. Etna: calculation of lava flow volume; calculation of erosion and deposition volume of pyroclastic cones; mapping of areas newly covered by volcanic ash; and morphological evolution of a portion of an active lava field over a short time span.  相似文献