被动微波遥感积雪参数反演方法进展

雪深(snow depth,SD)和雪水当量(snow water equivalent,SWE)是气候水文研究中的重要参数,在雪灾监测中尤为重要。首先,简要介绍了被动微波遥感SD和SWE反演算法的物理基础——积雪微波辐射传输模型,分析了不同微波频段、不同特点的积雪微波辐射和散射特性。然后,根据前人的研究从数学角度将反演算法分为线性亮温梯度法和基于先验知识法,总结了2类算法的优势和局限性:线性亮温梯度法相对简单、速度快,一般只适用于特定的研究区;先验知识法需要获取研究区的样本数据,并反复训练才能达到较好的精度,但对样本的独立性及其均值差异显著性的要求较高。最后,重点介绍了我国风云三号微波成像仪(FY-3 MWRI)的全球SD和SWE反演算法和针对中国区域的改进算法,并对未来的研究热点进行了展望。     

Biomarker responses in flounder (Platichthys flesus) and mussel (Mytilus edulis) in the Klaipeda-Būtinge area (Baltic Sea)

During the EU project BEEP a battery of biomarkers was applied in flounder (Platichthys flesus) and the blue mussel (Mytilus edulis) collected at three locations off the Lithuanian coast (Baltic Sea) in June and September 2001 and 2002. The elevated biomarker responses in specimens sampled in September 2001 were apparently related to the extensive dredging activities in the Klaipeda port area and subsequent dumping of contaminated sediments. High concentrations of organic pollutants (organochlorines and PBDEs) were also measured in the tissues of both indicator species. In addition, response levels of genotoxicity, cytotoxicity, immunotoxicity as well as concentrations of PAH metabolites in the bile of flounder showed elevations in 2002 after an oil spill in the Būtinge oil terminal in November 2001. In flounder, biomarker measurements 10 months after the spill indicated recovery processes but in mussels a high level of genotoxicity could still be observed 22 months later. The present study illustrates the usefulness of the multi-biomarker approach in the detection of biological effects of pollution in this region of the Baltic Sea.     

The BEEP project in the Baltic Sea: overview of results and outline for a regional biological effects monitoring strategy

Field studies in the framework of the EU funded BEEP project (Biological Effects of Environmental Pollution in Marine Coastal Ecosystems, 2001-2004) aimed at validating and intercalibrating a battery of biomarkers of contaminant exposure and effects in selected indicator species in the Mediterranean, the North Atlantic and the Baltic Seas. Major strategic goals of the BEEP project were the development of a sensitive and cost-efficient biological effects monitoring approach, delivery of information and advice to end-user groups, and the implementation of a network of biomarker researchers around Europe. Based on the main results obtained in the Baltic Sea component of the BEEP the present paper summarises and assesses the applicability of biomarkers for different regions and species in this sea area. Moreover, a general strategy and some practical considerations for the monitoring of biological effects in the Baltic Sea are outlined.     

Liver histopathology in Baltic flounder (Platichthys flesus) as indicator of biological effects of contaminants

Results are presented of a study on liver histopathology in Baltic flounder (Platichthys flesus) carried out in 2001 and 2002 in four coastal sampling areas of the Baltic Sea: Kv?d?fj?rden (Swedish east coast, reference area), Klaipeda-Butinge (Lithuanian coast), Gulf of Gdansk (Polish coast), and Wismar Bay (German coast) within the framework of the EU-funded BEEP project. Liver lesions were diagnosed and categorised using standardised methodologies and, for a spatial and temporal assessment of the prevalence and types of lesions detected, a scoring system was applied, involving the calculation of mean histopathology lesion scores. 83.0% of the 436 female flounder examined (size range: 20-43 cm total length, age range: 2-8 years) were affected by liver lesions, out of which 74.3% were assigned to the category of non-specific, 3.4% to the category of early toxicopathic non-neoplastic, 4.6% to the category of pre-neoplastic and 0.7% to the category of neoplastic lesions. Mean lesions scores were highest in the areas at the Lithuanian and Swedish coast and there is indication of an impact of the age structure of the flounder populations studied, the sampling season as well as of contaminant effects.     

全新世呼伦湖区植被和气候变化的孢粉记录

文章详细分析了内蒙古呼伦湖HL06岩芯沉积的孢粉组合,基于AMS 14C年代标尺,恢复了全新世湖区植被演变过程;并根据我国北方和蒙古表土孢粉数据和气象资料,建立了孢粉-气候参数转换函数,定量重建了呼伦湖区降水和气温的变化历史.结果表明,11000～8000aB.P.,湖区植被以蒿、藜占优,为干草原景观,气候暖干;8000～6400aB.P.,湖区禾本植物扩张,山地桦林发育,降水显著增加,气温逐渐降低;6400～4400aB.P.,湖区早生草本植物增加,降水减少,气温继续下降;4400～3350aB.P.,耐旱藜科植物大量生长,湖区荒漠化,气候极端干旱;3350～2050aB.P.,湖区草原植被有所恢复,降水略有增加,气温有所回升;2050～1000aB.P.,湖区蒿属植物减少,山地松林发育,气温降至全新世最低;最近1000年,藜科、禾本科等伴人植物大量出现,反映出人类活动对湖区自然环境的影响.全新世呼伦湖区气温变化在轨道尺度上受控于北半球太阳辐射量的变化,而在亚轨道尺度上可能与东亚夏季风强度有关.距今8000年前湖区降水较弱可能因为早全新世北半球高纬残存冰盖抑制了东亚季风雨带的北上,季风降水的千年-百年尺度波动与热带西太平洋海气相互作用密切相关.     

Testing an approach to OSL dating of Late Devensian glaciofluvial sediments of the British Isles

In the British and Irish Isles, the understanding of expansion and retreat of the last ice sheet in Marine Isotope Stage (MIS) 2 has been hindered by a lack of chronological control for the timing of its maximum extent and subsequent retreat stages. In this research, a suite of lithofacies from a former distal ice marginal sandur at Orrisdale, Isle of Man, were identified and selected for optically stimulated luminescence dating. Different‐size fractions of quartz grains were extracted from selected lithofacies types with the aim of identifying which depositional environments and grain size fractions are best suited for optical dating. Tests have been undertaken to identify the luminescence properties of this quartz, including preheat dose recovery and constant‐wave optically stimulated luminescence (OSL) decay curve fitting. Equivalent dose distributions for all samples were wide and positively skewed, indicative of heterogeneous bleaching. A comprehensive statistically based decision‐making protocol has been defined in order to find the appropriate statistical model for burial dose estimation. Ages in the range of 17–14 ka have been obtained which agree with the expected geologically constrained chronology. The Orrisdale Formation is contemporaneous with Heinrich Event 1 and the Killard Point Stadial identified in eastern Ireland ca. 16.4 ka. The suggested approach for OSL dating of glaciofluvial sediments has the potential for much wider application to high latitude or temperate areas where there is an abundance of such sediments and where improved chronological control is much needed. Copyright © 2009 John Wiley & Sons, Ltd.     

Assessing global Sentinel-2 coverage dynamics and data availability for operational Earth observation (EO) applications using the EO-Compass

ABSTRACT

Sentinel-2 scenes are increasingly being used in operational Earth observation (EO) applications at regional, continental and global scales, in near-real time applications, and with multi-temporal approaches. On a broader scale, they are therefore one of the most important facilitators of the Digital Earth. However, the data quality and availability are not spatially and temporally homogeneous due to effects related to cloudiness, the position on the Earth or the acquisition plan. The spatio-temporal inhomogeneity of the underlying data may therefore affect any big remote sensing analysis and is important to consider. This study presents an assessment of the metadata for all accessible Sentinel-2 Level-1C scenes acquired in 2017, enabling the spatio-temporal coverage and availability to be quantified, including scene availability and cloudiness. Spatial exploratory analysis of the global, multi-temporal metadata also reveals that higher acquisition frequencies do not necessarily yield more cloud-free scenes and exposes metadata quality issues, e.g. systematically incorrect cloud cover estimation in high, non-vegetated altitudes. The continuously updated datasets and analysis results are accessible as a Web application called EO-Compass. It contributes to a better understanding and selection of Sentinel-2 scenes, and improves the planning and interpretation of remote sensing analyses.     

Sikhote Alin' meteoroid: A contribution to the story of its fragmentation and fragment scattering

The correlation of the size and spatial distribution of fragments from the Sikhote Alin' meteoroid, 1947, was examined.With Frost's logarithmic rule of spatial sorting of meteorite fragments, supported by an ad hoc developed averaging procedure, a new approach to the size distribution was made possible.It was found that the meteoroid has been originally broken into several - presumably 5–6 - large fragments unequal in size, which further fragmented with various efficiency and speed.The conclusions are compatible with the reports of the witnesses of the fall of the meteorite.     

乌拉山金矿113含金石英脉围岩蚀变地球化学特征初步研究

本文研究了乌拉山金矿带１１３含金石英脉的围岩蚀变类型，蚀变分带及各带的常量元素（Ｋ、Ｎａ、Ｆｅ、Ｓｉ），成矿元素（Ａｕ、Ｃｕ、Ｐｂ、Ｚｎ）的分布特征，用聚类分析，Ｒ型因子分析讨论了元素组合特征和蚀变与矿化的关系。研究结果在乌拉山地区具有重要找矿意义。     

Devolution vs. regionalization of power in Britain and the USA: The consequences for citizen participation

The failure of experiments with both neighborhood government and regional government has led to attempts to weld these two administrative formats. The result is the federated local authority. The urban planning function in London, England, is utilized as an example to show the failure of the federated authority concept due to its dependence on a metropolitan spirit among its citizens and on a strict division in decision-making between area and local concerns. Neither is attainable so the experiment fails at least in regard to citizen expectations concerning involvement. The proposed solution involves a weaker role for the borough or neighborhood units in the federation and an effort to support and encourage citizen involvement in decision-making via the political process. Disparities in political resources are rectified by recourse to watchdog groups to balance the growing power of technocratic planners.