实际伽利略搜救信号参数估计的Cramer-Rao界

考虑调制不对称度和信息位宽的不确定度,研究了实际伽利略搜救信号信息位宽、到达频率(FOA)、到达时间(TOA)估计的Cramer-Rao界(CRB).推导了伽利略搜救信号Fisher信息矩阵中各元素的计算表达式,利用单位冲激函数的性质和Parseval定理,将单位冲激函数的平方和转换到频域进行计算,得到了信息位宽、FOA和TOA估计的CRB的解析结果.数值分析和Monte Carlo仿真结果表明,CRB具有有效性,可以用于评估上述参数估计算法的性能.     

一阶脉宽调制型负载

针对目前负载模拟器动态和时变特性的局限性,提出了一种新的一阶电气负载设计方法。该方法借助调节负载开关管的导通时间实现电气负载的切换,以模拟一定参数范围内的任意一阶目标负载,通过单位周期内负载响应曲线的“函数距离”在负载曲线面积中所占的比例评判负载的模拟程度。对任意给定的实际负载使用其截止频率信号作为输入进行仿真,结果显示：对截止频率分别为20、50、80Hz的3个负载进行模拟,PWM的周期T为1 ms,占空比δ分别为9.9%、39.4%、69.1%,模拟偏差为1.48%、3.92%、3.57%,可见其负载模拟程度很高。仿真实验表明用该方法设计的一阶电气负载能够模拟一定参数范围内的任意一阶负载。     

Sea surface temperature records of core ZY2 from the central mud area in the South Yellow Sea during last 6200 years and related effect of the Yellow Sea Warm Current

Sea surface temperature (SST) records in the South Yellow Sea during the last 6200 years are reconstructed by the unsaturation index of long-chain alkenones (K 37 U ’) in sediment core ZY2 from the central mud area.The SST records varied between 14.1 and 16.5°C (15.6°C on average),with 3 phases:(1) A high SST phase at 6.2-5.9 cal ka BP;(2) A low and intensely fluctuating SST phase at 5.9-2.3 cal ka BP;and (3) A high and stable SST phase since 2.3 cal ka BP.Variation of the SST records is similar to intensity of the Kuroshio Current (KC),and corresponds well in time to global cold climate events.However,the amplitude of the SST response to cooling events was significantly different in different phases.The SST response to global cooling event was weak while the KC was strong;and the SST response was strong while the KC was weak.The difference in amplitude of the SST response is possibly caused by the modulation effect of the Yellow Sea Warm Current which acts as a shelf branch of the KC and a compensating current induced by the East Asia winter monsoon.The warm waters brought by the Yellow Sea Warm Current cushion the SST decrease induced by climate cooling,and both the Kuroshio and East Asian winter monsoon play important roles in the modulation mechanism.The SST records display a periodicity of 1482 years.The same period was found in the KC records,indicating that variation of the SST records in the central South Yellow Sea is strongly affected by KC intensity.The same period was also found in Greenland ice cores and North Atlantic and Arabian Sea sediment cores,showing a regional response of marine environmental variability in the East China Seas to that in the global oceans.     

Forced response of atmospheric oscillations during the last millennium simulated by a climate system model

Variations in global atmospheric oscillations during the last millennium are simulated using the climate system model FGOALS_gl. The model was driven by reconstructions of both natural forcing (solar variability and volcanic aerosol) and anthropogenic forcing (greenhouse gases and sulfate aerosol). The model results are compared against proxy reconstruction data. The reconstructed North Atlantic Oscillation (NAO) was out of phase with the Pacific Decadal Oscillation (PDO) in the last millennium. During the ...     

The methodology of quantitative assess economic output of climate change

A method is introduced in this paper to study the effect of future climatic change on the economy. The researchers determine the economic output of climate change from historical data, and provide a method to quantitatively predict economic output of climate change by an economic-climatic model. A historical reciprocating examination is used to analyze output data for various crops in eight agricultural areas in China and meteorological data from 160 observatories in China from 1980 to 2000. The results show that the methods used are reasonable to a certain extent and good in application.     

Changes in physical features of Glacier No. 1 of the Tianshan Mountains in response to climate change

This study analyzes the changes in glacier zones and snow composition of Glacier No.1 in the Tianshan Mountains of China since 1961,and their possible relations with climate.It is found that precipitation dominated the snow composition and that air temperature and precipitation controlled the distribution of glacier zones,but interannual change in precipitation had a relatively large effect on glacier zones and snow composition during 1963–1981 (P10) and 1963–1989 (P11).However,during 1982–2007 (P20) and 19...     

楚雄市气候变化及对水资源的影响

利用楚雄市1961～2010年50 a的气候和水资源等资料,分析了楚雄市近半个世纪以来气候的变化及其对径流、水资源变化的影响.分析结果表明:50 a来楚雄市各季和年平均气温均呈上升趋势,年平均气温以0.33℃/10 a速率上升,冬季平均气温增暖速率最为显著;近50 a来楚雄市年降水量有增多的趋势,以21.26mm/10 a的速度在递增.春季和夏季降水量增加较多;而冬季和秋季平均降水量则呈缓慢增多的趋势.水资源总量、地表水径流量、地下水呈减少趋势.     

（F,F）-数据离散矩形区域在数据辨识中的应用

应用新数学模型P-集合,提出数据传输中三种异常数据的概念：F-异常数据、F-异常数据与（F,F）-异常数据;提出（F,F）-数据离散矩形区域概念;给出丢失-侵入数据发现定理、系统输出数据分离定理、系统输出数据类型辨识定理、（F,F）-异常数据在（F,F）-数据离散矩形区域的定位定理;给出（F,F）-数据离散矩形区域在系统输出数据类型辨识中的应用。丢失-侵入数据发现定理与系统输出数据分离定理是系统输出数据类型辨识的基础,（F,F）-数据离散矩形区域的提出,为系统数据的几何辨识和系统出现异常数据的预警提供了一种新的理论与方法。     

温室气体稳定目标下部门减排责任分解方法

为了探讨气候变化背景下温室气体排放权分摊机制这一研究难点,综述了温室气体减排责任分解方法的研究现状,遵循"共同但有区别的责任"思想并利用WRE稳定性廓线和IEA/SMP交通模型,开发了SMP-WRE模型。应用该模型建立了一种产业部门具体减排责任的分解方法,并以中国轻型车部门为例,展示了该方法的实现过程。结果表明:全球轻型车的基准排放是目标排放的2~4倍,说明轻型车部门实现450×10-6和550×10-6的CO2稳定水平难度很大。目标分解后的地区排放变化率欧美国家较小、中国较大,原因是欧美汽车市场规模饱和,而中国汽车正爆发式增加,排放增加不可避免。     

多层次降尺度方法对安徽省月降水量预测的研究

 利用1961～2004年多层次的NCEP环流资料初选出与台站月降水量的显著相关区,通过最优子集回归模型对各初选因子进行筛选和组合,形成了安徽省35个台站的月降水量回归模型,并分别利用NCEP资料和月动力延伸模式环流预报作为输入场对2005～2009年安徽省月降水量进行了回报.结果表明,该降尺度模型包含高低层的多种资料,各因子组合起来可以从统计上反映出一些影响降水的环流配置型,较传统的仅用500hPa资料的降尺度模型内容更为丰富.从回报的效果来看,预测值与实况值平均距平符号一致率为63%,PS评分为75分,其中对涝月的预测效果要好于旱月.