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1.
相对辐射定标是获得各类光学遥感卫星传感器的高精度观测产品的必备条件,由于受发射震动、在轨空间环境变化等因素以及传感器自身衰减的影响,传感器在轨响应状态会随时间发生衰减和漂移,单一相对辐射定标方法无法保障卫星传感器在特定时间的探元响应一致性。本文以光学卫星传感器全生命周期影像辐射质量保障为目标,主要研究了光学卫星传感器在轨生命周期内高频率、高定标精度的常态化相对辐射定标方法,并总结了当前常用的相对辐射定标精度评估方法,评估了各定标方法的指标以及应用场景。利用珞珈一号01星(LJ1-01)夜光传感器获取的影像进行在轨暗电流、和在轨均匀场地定标实验和验证,珠海一号02组高光谱卫星影像被用来实施和验证统计定标和偏航辐射定标方法,并耦合多种定标方法实现常态化辐射定标。实验结果表明:各种定标方法处理后影像的条纹系数小于0.25%,图像相对标准差均优于3.00%;多种定标方法相互结合的常态化辐射定标方法实现了多种定标方法的优势最大化,完成常见传感器的高精度在轨标定。 相似文献
2.
2018年8月19日,在斐济东部海域563 km深处发生了一次MW8.2地震.我们首先挑选位于美国阿拉斯加地区的131个宽频带台站构成台阵,选用垂直分量0.5~2 Hz的高频信号,利用广义台阵反投影技术对这次地震的破裂过程进行了成像,然后基于破裂速度对地震的辐射效率进行了估计.结果表明,这次地震总体上呈单侧破裂,破裂方位在3.0°左右,破裂总长度约51 km,持续时间22 s,平均破裂速度为2.5 km·s-1.但能量释放有2次高峰,形成两次子事件.第一次为前10 s,峰值在7 s左右,破裂速度为2.9 km·s-1,辐射效率为45%.第二次为10~22 s,峰值在15 s左右,破裂速度为1.6 km·s-1,辐射效率为26%.结合震源位置、震源机制、破裂速度以及辐射效率,我们认为这次地震是由于俯冲板块前缘受到下部地幔物质上浮阻力引起的剪切失稳所致,起初板块内部的脆性破裂表现突出,致使辐射效率较高,后来震源处高温高压下的熔融耗散特征逐渐凸现,致使辐射效率下降. 相似文献
3.
为进一步研究WOFOST模型在河南省冬麦区的适用性,以河南省30个农业气象观测站1991—2014年冬小麦观测资料、历史气象资料和土壤资料为依据,对WOFOST模型进行逐站调参和验证,分别建立了30个站的冬小麦模型参数。其中1991—2010年为模型调参年份,2011—2014年为模型验证年份。各站开花期和成熟期调参模拟的归一化均方根误差NRMSE分别小于5%和3%,验证误差分别为3.7%和2.9%。除潢川和固始外,模型对其余各站产量模拟的归一化均方根误差NRMSE全省各站均小于20.0%,验证误差全省平均为15.2%,大部分站点观测值和模拟值相关系数r通过了显著检验。利用调参后的模型模拟2011—2014年冬小麦生长动态变化可知,模拟地上部总干物重与实测单株干物重、模拟LAI与单株叶面积有较一致的变化趋势,拟合度较高。因此,WOFOST模型对河南省冬小麦主要发育阶段、产量及干物质积累模拟能力较强,具有良好的应用前景。 相似文献
4.
Automated Extraction of a Five‐Year LA‐ICP‐MS Trace Element Data Set of Ten Common Glass and Carbonate Reference Materials: Long‐Term Data Quality,Optimisation and Laser Cell Homogeneity 下载免费PDF全文
LA‐ICP‐MS is increasingly applied to obtain quantitative multi‐element data with minimal sample preparation, usually achieved by calibration using reference materials (RMs). However, some ubiquitous RMs, for example the NIST SRM 61× series glasses, suffer from reported value uncertainties for certain elements. Moreover, no long‐term data set of analyses conducted over a range of ablation and tuning conditions exists. Thus, there has been little rigorous examination of the extent to which offsets between measured and reported values are the result of error in these values rather than analytically induced fractionation. We present new software (‘LA‐MINE’), capable of extracting LA‐ICP‐MS data with no user input, and apply this to our system, yielding over 5 years of data (~ 5700 analyses of ten glass and carbonate RMs). We examine the relative importance of systematic analytical bias and possible error in reported values through a mass‐specific breakdown of fourteen of the most commonly determined elements. Furthermore, these data, obtained under a wide range of different ablation conditions, enable specific recommendations of how data quality may be improved, for example the role of diatomic gas, the effect of differential inter‐glass fractionation factors and choice of transport tubing material. Finally, these data demonstrate that the two‐volume Laurin ablation cell is characterised by no discernible spatial heterogeneity in measured trace element ratios. 相似文献
5.
6.
基于一维综合孔径微波辐射计的海面温度反演研究 总被引:1,自引:0,他引:1
Due to the low spatial resolution of sea surface temperature(T_S) retrieval by real aperture microwave radiometers,in this study, an iterative retrieval method that minimizes the differences between brightness temperature(T_B)measured and modeled was used to retrieve sea surface temperature with a one-dimensional synthetic aperture microwave radiometer, temporarily named 1 D-SAMR. Regarding the configuration of the radiometer, an angular resolution of 0.43° was reached by theoretical calculation. Experiments on sea surface temperature retrieval were carried out with ideal parameters; the results show that the main factors affecting the retrieval accuracy of sea surface temperature are the accuracy of radiometer calibration and the precision of auxiliary geophysical parameters. In the case of no auxiliary parameter errors, the greatest error in retrieved sea surface temperature is obtained at low T_S scene(i.e., 0.710 6 K for the incidence angle of 35° under the radiometer calibration accuracy of0.5 K). While errors on auxiliary parameters are assumed to follow a Gaussian distribution, the greatest error on retrieved sea surface temperature was 1.330 5 K at an incidence angle of 65° in poorly known sea surface wind speed(W)(the error on W of 1.0 m/s) over high W scene, for the radiometer calibration accuracy of 0.5 K. 相似文献
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8.
HY-2 A (Haiyang-2 A) satellite was launched on August 16, 2011 and radar altimeter is one of its main payloads. We reprocessed two years of HY-2 A altimeter sensor geophysical dataset records (SGDR) data. This paper presents the main results in terms of reprocessed HY-2 A altimeter data quality: verification of data availability and validity, monitoring several relevant altimeter parameters, and assessment of the HY-2 A altimeter system performances. A cross-calibration analysis of reprocessed HY-2 A altimeter data with Jason-2 was conducted. The reprocessed HY-2 A altimeter data show good quality and have a low level of noise with respect to Jason-2. The same geophysical correction methods were used to calculate the sea surface height (SSH) for the two missions. The mean standard deviations of the crossover differences for HY-2 A and Jason-2 are 5.24 cm and 5.34 cm, respectively. The mean standard deviation of the crossover differences between HY-2 A and Jason-2 is 5.37 cm. These show that HY-2 A can provide SSH measurements at almost the same level of accuracy as Jason-2. The relative SSH bias between HY-2 A and Jason-2 due to the Ultra Stable Oscillator (USO) drift is obviously observed, and it can affect the calculation of mean sea level and should be further studied and corrected. 相似文献
9.
本文运用CloudSat卫星上搭载的雷达探测数据和AQUA卫星搭载的辐射光谱仪探测数据,选择2007年1月至2010年12月期间,地理位置位于(15°~45°N,145°~165°E)区域内(远海)发生的云场数据开展分析,研究云的物理结构特征与其光谱辐射特性的相互关系。不同光谱波段对云物理结构变化的响应情况各有不同,首先从MODIS光谱仪22个云相关光谱波段中分析并选择出与云物理结构特征密切相关的光谱组合(包含13个波段),而后开展了这些光谱波段的云辐射特性与云物理结构特征的相互变化关系研究。统计分析表明,在外部大气、地表条件以及太阳入射辐射变化不大情况下,云的结构变化与其光谱辐射变化之间总体存在单调相关关系,物理结构变化不大的云廓线之间其光谱辐射的变化也小,反之也成立,即光谱辐射变化小的云廓线之间物理结构变化也小。从而,对于某些内部物理结构特征未知的云,利用与其光谱辐射特性相近的云结构数据可实现自身垂直结构信息的重建。基于光谱辐射相近则云物理结构很可能相近的特点,本文对未知云场的物理结构重建开展了模拟试验,试验结果表明光谱相近原则匹配物理结构的方法一定程度上能够实现云物理结构的构建,为利用被动遥感数据推测云物理结构特征研究提供参考。 相似文献
10.
Emission reductions improve the chances that dangerous anthropogenic climate change will be averted, but could also cause some firms financial distress. Corporate failures, especially if they are unnecessary, add to the social cost of abatement. Social value can be permanently destroyed by the dissolution of organizational capital, deadweight losses paid to liquidators, and unemployment. This article proposes using measures of corporate solvency as an objective tool for policy makers to calibrate the optimal stringency of climate change policies, so that they can deliver the least loss of corporate solvency for a given level of emission reductions. They could also be used to determine the generosity of any compensation to address losses to corporate solvency. We demonstrate this approach using a case study of the UK’s Carbon Price Support (a carbon tax).
Key policy insights
Solvency metrics could be used to empirically calibrate the optimal stringency of climate policies.
An idealized solvency trajectory for firms affected by climate change policy would cause corporate solvency to initially decline – approaching but not exceeding ‘distressed’ levels – and then gradually improve to a new ‘steady state’ once the low-carbon transition had been achieved.
In terms of the UK’s Carbon Price Support, corporate solvency of energy-intensive industries was found to be stable subsequent to its introduction. Therefore, the available evidence does not support its later weakening.