Validation of Landslide Susceptibility Maps; Examples and Applications from a Case Study in Northern Spain

A procedure for validating landslide susceptibility maps wasapplied in a study area in northern Spain and the results obtained compared. Validationwas used to carry out sensitivity analysis for individual variables and combinationsof variables. The validity of different map-making methods was tested, as well as theutility of different types of Favourability Functions. The results obtained show thatvalidation is essential to determine the predictive value of susceptibility maps. Italso helps to better select the most suitable function and significant variables, thus improving the efficiency of the mapping process. Validation based on a temporal strategy makes it possible to derive hazard maps from susceptibility maps.     

基于客观分析的多源卫星叶绿素a浓度产品融合方法研究

本文基于Aqua/MODIS、Terra/MODIS和Envisat/MERIS多源卫星叶绿素a浓度产品,研究了客观分析融合方法,制作了西北太平洋海域(0°~50°N,100°~150°E)叶绿素a浓度融合产品,并从有效数据空间覆盖率和产品精度两个方面对融合方法进行了评价。与单传感器以及欧洲太空局发布的GSM模型业务化融合产品相比,客观分析融合产品空间覆盖率明显提高;与收集的2002-2012年间叶绿素a浓度实测数据比较,GSM模型业务化融合产品的匹配数据点为578个,偏差为-0.20 mg/m3,均方根误差为0.37 mg/m3,客观分析法融合产品的匹配数据点为1432个,偏差为-0.21 mg/m3,均方根误差为0.36 mg/m3。结果表明:本文研究的客观分析融合方法在保证融合产品精度的同时可显著提高产品的空间覆盖率,在海洋水色融合应用前景广阔。     

Global Statistical Assessment and Cross-Calibration with Jason-2 for Reprocessed HY-2 A Altimeter Data

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.     

黔北遵义团溪铝土矿勘探网密度探讨

以黔北遵义团溪铝土矿后槽矿区一矿块为例,用50m×50m工程间距进行施工成果与100m×50m和100m×100m工程间距施工成果,对其矿体厚度、矿体形态、主要化学成分含量及储量变化进行分析对比,以探寻此类矿床应如何选择工程间距,才能更合理准确地对矿体进行圈定控制,以满足矿山开采设计的要求。通过资料分析对比认为,对黔北喀斯特型沉积铝土矿进行勘查而言,以≤50m×50m工程间距控制矿体并求取储量,效果较为理想。     

基于AMSR-E的北疆地区积雪深度反演

利用北疆地区2007/2008-2009/2010年度积雪季(12月至次年2月)的AMSR-E降轨19 GHz与37 GHz波段的水平极化亮温数据, 结合北疆地区45个气象台站的实测雪深数据, 建立了北疆地区基于AMSR-E亮度温度数据的雪深反演模型, 并对模型的精度进行评价. 结果显示: 雪深在3~10 cm时, 模型反演的雪深值负向平均误差为-5.1 cm, RMSE值为6.1 cm; 雪深在11~30 cm时, 模型反演雪深值的平均误差仅为2.6 cm, RMSE、 正向平均误差、 绝对平均误差均较小; 雪深大于30 cm时, 模型反演的各项误差较大. 用合成方法反演北疆地区2006/2007-2010/2011年度5个积雪季的平均雪深分布和最大雪深分布, 结果显示北疆地区积雪主要分布于北部阿尔泰山和南部天山一带, 其中阿勒泰地区所占比重最大, 中部的准噶尔盆地腹地、 克拉玛依地区雪层较浅.     

Is Prediction of Future Landslides Possible with a GIS?

This contribution explores a strategy for landslide hazard zonation inwhich layers of spatial data are used to represent typical settings inwhich given dynamic types of landslides are likely to occur. Theconcepts of assessment and prediction are defined to focus on therepresentation of future hazardous events and in particular on themyths that often provide obstacles in the application of quantitativemethods. The prediction rate curves for different applications describethe support provided by the different data layers in experiments inwhich the typical setting of hazardous events is approximated bystatistically integrating the spatial information.     

Age and growth of Cape stumpnose Rhabdosargus holubi (Pisces: Sparidae) in the Eastern Cape,South Africa

Rhabdosargus holubi is a small (maximum weight=2.4?kg) yet important fishery species in the estuaries of the south-east coast of South Africa. Little is known of its biology and specifically its growth rate, which is essential for sustainable management of the fishery. We examined and counted the opaque zones in the sectioned otoliths of 134 R. holubi to determine its age and growth parameters. The otoliths from two recaptured fish marked with oxytetracycline confirmed that one opaque zone was deposited annually. The species reached a maximum age of 18 years and growth was adequately described by a von Bertalanffy growth function of the form: L_t = 358.1 (1 – e^{?0.24(t+0.77)}) mm fork length. There were no significant differences between any of the male and female growth parameters (likelihood ratio test: p = 0.3). The growth was slow (omega index: ω = 86.56); however, despite this, the unique life history of R. holubi may provide a degree of resilience to heavy fishing pressure in estuaries.     

Estimation of the temporal autocorrelation structure by the collocation technique with an emphasis on soil moisture studies

Abstract

The collocation technique has become a popular tool in oceanography and hydrology for estimating the error variances of different data sources such as in situ sensors, models and remote sensing products. It is also possible to determine calibration constants, for example to account for an off-set between the data sources. So far, the temporal autocorrelation structure of the errors has not been studied, although it is known that it has detrimental effects on the results of the collocation technique, in particular when calibration constants are also determined. This paper shows how the (triple) collocation estimators can be adapted to retrieve the autocovariance functions; the statistical properties as well as the structural deficencies are described. The coupling between the autocorrelation of the error and the estimation of calibration constants is studied in detail, due to its importance for analysing temporal changes. In soil moisture applications, such time variations can be induced, for example, by seasonal changes in the vegetation cover, which affect both models and remote sensing products. The limitations of the proposed technique associated with these considerations are analysed using remote sensing and in situ soil moisture data. The variability of the inter-sensor calibration and the autocovariance are shown to be closely related to temporal patterns of the data.

Editor D. Koutsoyiannis

Citation Zwieback, S., Dorigo, W., and Wagner, W., 2013. Estimation of the temporal autocorrelation structure by the collocation technique with an emphasis on soil moisture studies. Hydrological Sciences Journal, 58 (8), 1729–1747.     

High‐resolution seismic monitoring of instrumented buildings using a model‐based state observer

This paper proposes a model‐based state observer to perform high‐definition response estimation in partially instrumented building structures. The proposed estimator is verified in a simulated five‐story shear‐building structure and validated using measurements from a seven‐story reinforced concrete building slice tested at the NEES‐University of California at San Diego shake table. In both cases the proposed estimator yielded satisfactory results by estimating the time history of shear forces, bending moments, displacements, and strains at various points/sections of interest. The proposed algorithm can be used in instrumented buildings for various practical applications such as post‐earthquake damage assessment, structural control, and building code calibration. Copyright © 2016 John Wiley & Sons, Ltd.