应用AMSR-E 89 GHz遥感数据反演北极多年冰密集度

被动微波辐射计AMSR-E在89GHz频段的空间分辨率几乎是其它低频段的2倍。到目前为止,已经有成熟的算法采用AMSR-E 89GHz频段的数据来反演整体海冰的密集度,而本文根据89GHz频段亮温数据针对一年冰、多年冰以及无冰水面的不同特性,提出了一种反演多年冰密集度的方法(AC)。计算了2007年北极的整体海冰和多年冰密集度,并与NASA TEAM算法(NT)的结果作了比较。对于整体海冰密集度,两种算法反演的结果基本一致。从日平均上来看,AC算法得到的整体海冰覆盖面积只比NT算法多25万km2。但是对于多年冰的反演结果,AC算法得到的结果比NT的结果要多出146万km2,冬季差别尤其大。造成这种差别的原因可能是AC算法对于北极表面气温的变化比较敏感。另外,AC算法计算得到2007年最大海冰覆盖面积为1400万km2,最小海冰覆盖面积为400万km2,这与其它研究结果一致。     

基于北极多源卫星数据的海冰厚度时空变化对比与评估

海冰厚度作为海冰的重要变量之一,相较于海冰密集度、海冰漂移速度、海冰范围等,数据时空完整性仍然不足。当前获取北极海冰厚度的主要手段为卫星遥感,除之前的CryoSat-2、SMOS等卫星,2018年11月又新增了ICESat-2卫星。目前,针对北极多源卫星海冰厚度的时空变化差异性对比以及数据精度评估的工作较少,因此,本研究通过选取最近的完整两年(2019—2020年)内的ICESat-2、CryoSat-2以及CS2SMOS(CryoSat-2和SMOS融合产品)海冰厚度数据进行对比分析,量化其时空差异。结果显示,整体上CryoSat-2卫星数据的平均海冰厚度最大, ICESat-2其次, CS2SMOS最小。三种卫星数据间的差异具有明显的时空变化特征,在海冰厚度高值区ICESat-2数据的厚度最大, CryoSat-2与CS2SMOS数据的厚度相近,而在海冰边缘区CryoSat-2数据的厚度最大, CS2SMOS最小。从区域来看,不同卫星数据反演的海冰厚度在东西伯利亚海和波弗特海区域差异较小,在巴伦支海区域差异较大。在此基础上,利用研究时段内的“冰桥行动”实地观测数据对多源卫星数据进行...     

一个北极区域冰海耦合模式的设置与应用

介绍了一个北极区域冰-海耦合数值模式的设置与应用。海洋模式基于MIT海洋环流数值模式,海冰动力学过程由Hibler的粘-塑模型发展而来。海冰的热力过程基于Winton提出的三层热力学模型。给出了耦合模式的基本框架,重点介绍了区域冰-海耦合系统中较为重要的程序包,如正交网格生成技术,中尺度涡的参数化,冰-海耦合及开边界处理等。以NCEP再分析资料为大气强迫场,模拟研究了北极夏季海冰范围异常的变化特征(1992—2007),模拟得到的海冰面积变化趋势与SSM/I观测资料进行了对比,两者相关系数达到0.88,模式基本反映了海冰的年际变化特征。以2007年为例,对比分析了9月份海冰密集度分布特征,模式结果得到的海冰范围略大于观测,但基本反映了2007年夏季海冰范围的衰减形态。     

北极海冰密集度遥感数据产品对比及航道关键区验证研究

为分析并评价海冰边缘区海冰密集度数据产品,选取北冰洋区域8种公开发布的产品,基于平均偏差和标准差(Standard Deviation, SD)展开分析,结果表明:Bremen/ASI(ARCTIC Sea Ice)、Bremen/BT (Bootstrap)、NSIDC(National Snow and Ice Data Center)/BT和NSIDC/CDR(Climate Data Record)四种数据全年平均偏差整体高于平均值,在夏季偏差高于冬季; Hamburger/ASI全年平均偏差低于平均值,冬春季偏差为负,夏季梢高于均值; NSIDC/NT(NASA Team)、NOAA OI SIC(National Oceanic and Atmospheric Administration Optimum Interpolation Sea Ice Concentration)和OSISAF(The Ocean and Sea Ice Satellite Application Facility)三种数据全年平均偏差为负,夏季负向增加;夏季和秋季标准差较大区域主要分布在东北航道薄冰区,东西伯利亚、拉普捷夫海和喀拉海区域标准差变化较大,从3%增加到10%～15%。围绕航道区,以MODIS(Moderate Resolution Imaging Spectroradiometer)影像作为参考,对8种数据的对比评估结果表明:在25km空间分辨率下,Bremen发布的两种数据相关性较高,均为0.80;NOAAOISIC数据相关性最低,为0.63; Bremen/BT平均偏差较小,为7.11%;基于ASI算法的Bremen/ASI数据和Hamburger/ASI数据平均偏差较大,分别为14.38%和14.99%,且在夏季和秋季偏差波动较大,对应标准差分别为12.16%和11.01%。该项研究对于提升遥感数据产品在海冰边缘或航道区的应用及进一步的算法研发具有指导意义。     

北极多源积雪深度数据对比评估及其对海冰厚度估算的影响

积雪深度是估算海冰厚度重要的参数之一,目前对不同积雪深度产品精度及其可适用范围的评估研究较少,也缺乏系统性的认知。本研究选取了11种北极积雪深度产品,根据产品的不同时间范围,分为2013—2018年和2018—2019年2个评估时间段。根据上述时间段,对比分析了各产品之间的差异性,然后将这些产品与“冰桥行动”和海冰质量平衡浮标的现场观测结果进行了评估。所有产品都显示格陵兰岛和加拿大北极群岛的北部积雪深度较厚,而在东西伯利亚海、拉普捷夫海、喀拉海、巴伦支海沿线区域的积雪深度较薄,不过,部分产品在时空变化上仍存在较大差异。与“冰桥行动”的观测数据对比发现,大部分产品数据雪深都较厚, AMSR2B和IS2/CS2分别在2013—2018年和2018—2019年的评估时间段内差异较小,拟合度较好。与海冰质量平衡浮标的对比结果显示,绝大部分产品数据雪深都较薄,并且差异性较大,其中NESOSIM在整个时期拟合度较好。利用不同产品的积雪深度反演海冰厚度的结果差异显著,与“冰桥行动”观测的海冰厚度对比发现, FY3B/MWRI和IS2/CS2分别在2013—2018年和2018—2019年的评估时间段...     

船载卫星遥感图象处理系统在南北极科学考察中的应用

船载卫星遥感图象处理系统是针对南极考察气象航线预报、冰区航行的海冰预报和导航需要而研制的船陆两用多功能软件系统。采用了最新的 DEL PHI可视化软件开发工具 ,开发了用于 WINDOWS98环境下的 32位的程序 ,并针对接收系统开发了 WINDOWS设备驱动程序 ,提高了在 WIND0 WS98多任务环境下 ,接收程序的实时性和可靠性 ;采用面向对象的程序开发方法和开放式的体系结构 ,便于功能的更新和提高 ;采用 SGP4/SDP4轨道模式及两行元素的轨道参数计算出卫星星下点的位置 ,实现了在 1 A图象上计算逐点经纬度的快速动态定位和图象显示的功能 ;采用迭代法利用电子地图网格数据 ,在接收的卫星云图上迭代套上地形及海岸线。组成了适合船陆两用的多功能快速灵活的图象处理系统 ,可以在 1～ 2分钟瞬间内完成一幅图的定位套网格和套地形线的工作。解决了南极海冰监测和冰缝、水道预报的难点。可以使图象上下滚动、左右移动、任意放大、缩小和剪取 ;可以随着鼠标的移动显示出图上任意一点的经纬度 ;能够在图上标出任意目标物 ,如船位、站位、岛屿等等 ;能够方便地在图上画出航线 ,直观地判断船所处的位置和航线周围的气象和海洋环境状况 ;解决了在茫茫海洋和冰区中航行找不到参照物时的困惑 :能够输出任意大小的 2 4位真     

区域发展规划风险生成与经营理论及应用

风险型区域发展规划 (简称风险规划 )是面向新世纪我国市场经济条件下为根治规划编制与实施病理 ,最大限度地提高规划编制与实施质量以及实施的经济、社会和生态环境效益而推行的新兴规划生成与经营形式。本文从风险规划的概念界定与兴起缘由入手 ,尝试探讨了风险规划的竞标、契约、盲审、决策、保险、营销、保值和增值等生成与经营模式 ,为确保风险规划顺利运行 ,建议建立风险规划立法保障制度、风险规划投资基金制度、风险规划公众征询与听证制度和风险规划执业制度。最后以珠江源头第一县沾益县经济社会发展规划为例 ,分析了沾益县风险规划生成与经营的具体过程。     

应用风云三号D星微波数据估算北极海冰面积和边缘线的精度评估

风云三号D星搭载的微波成像仪(microwave radiation imager,MWRI)可提供被动微波数据以实现全北极尺度的海冰面积和海冰边缘线研究。基于MWRI数据获取北极海冰面积和海冰边缘线的相关研究较少,且精度验证工作不足。使用基于6种算法的MWRI数据的海冰密集度结果,提取北极的海冰面积和海冰边缘线,将专用传感器微波成像仪/探测仪(special sensor microwave imager/sounder, SSMIS)和先进微波扫描辐射计(advanced microwave scanning radiometer2,AMSR2)数据作为对比,使用中分辨率成像光谱仪(Moderate-Resolution Imaging Spectroradiometer, MODIS)融合产品(2019年8月26日—12月31日)评估精度。结果表明, MWRI数据的海冰面积随时间变化的趋势与MODIS融合产品基本保持一致。MWRI提取的海冰边缘线相比SSMIS更接近MODIS融合产品获得的结果,均方根误差约为20～30 km。这些差异主要和数据间时空分辨率有关。总之, MWRI具...     

应用遥感方法估算区域蒸散量的制约因子分析

遥感方法估算区域蒸散量应用比较广泛的有两种,一种是完全以地表热量平衡方程为基础．用遥感方法估算出净辐射、土壤热流量和显热通量,然后用余项法求出蒸散量;另一种是以Penman—Monteith方程为基础．结合地表热量平衡方程,直接估算出蒸散量。本文根据国内外的研究现状,对应用遥感方法估算区域蒸散量的制约因子进行了深入的分析,这些制约因子包括(1)图像信息源;(2)反照率、比辐射率和表面温度等地表参数的遥感反演精度;(3)空气动力学阻抗和表面阻抗模型;(4)估算结果的验证方法(5)时间尺度的扩展问题。分析结果表明：长期以来由于这些因子中所涉及到的许多关键技术和难点问题都没得到很好的解决,因而极大地制约着应用遥感方法估算区域蒸散量的发展。通过对制约因子的分析．可以有助于高精度遥感蒸散模型的建立。     

《遥感图像应用处理与分析》评介

人类已经进入信息社会。作为获取地球资源与环境信息 ,揭示地球奥秘新手段的卫星遥感技术受到世界各国广泛重视。新的遥感卫星陆续升空 ,遥感仪器不断更新换代。然而遥感应用的发展相对滞后 ,地面站接收处理出的海量遥感数据未能快速及时转化为真正能够满足各行各业实际需要 ,可供决策依据的有用信息 ,以致遥感数据爆炸的局面 ,随着遥感技术的发展而日趋严重。为了促进遥感应用赶上遥感技术的发展步伐 ,国内外许多科学家从不同角度开展试验研究 ,陆续取得不少有意义的进展。其中戴昌达及其同事在发展遥感图像应用处理与分析技术 ,提高遥感应用水平 ,扩展遥感应用新领域方面取得的丰硕成果特别引人关注。他们在长期从事遥感应用     

A fast,free-form rubber-sheet algorithm for contiguous area cartograms

This article presents a fast, free-form rubber-sheet (Carto3F) algorithm for the construction of contiguous area cartograms. Rubber-sheet algorithms are influential and popular because of their conceptual simplicity. Existing rubber-sheet algorithms, however, tend to be algorithmically inefficient and computationally slow. More critically, they cannot completely preserve topology. Carto3F specifically improves rubber-sheet algorithms in these two aspects. First, with a spatial structure of quadtree and a mathematical condition for topological equivalence, Carto3F can prevent topological errors and guarantees topological integrity. Second, Carto3F is designed with efficiency as a priority. Its efficiency is primarily gained through using the auxiliary quadtree to reduce the number of points to be transformed. Furthermore, Carto3F allows parallel computation and can fully take advantage of the increasingly common multi-core, multi-thread processors. Based on the mathematical analysis, Carto3F also mitigates the effect of force cancellation that is inherent in rubber-sheet algorithms. On a computer equipped with a 2.4-GHz quad-core CPU, Carto3F can produce quality population cartograms of the United States, China, and the world within 1 second, 18 seconds, and 8 minutes, respectively. Quantitative measures show that Carto3F outperforms the optimized rubber-sheet algorithm and the diffusion algorithm in both transformation effectiveness and computational efficiency.     

Glacial and palaeoenvironmental history of the Cape Chelyuskin area, Arctic Russia

Quaternary glacial stratigraphy and relative sea-level changes reveal at least two glacial expansions over the Chelyuskin Peninsula, bordering the Kara Sea at about 77°N in the Russian Arctic, as indicated from tills interbedded with marine sediments, exposed in stratigraphic superposition, and from raised-beach sequences mapped to altitudes of at least up to ca. 80 m a.s.l. Chronological control is provided by accelerator mass spectrometry ¹⁴C dating, electron-spin resonance and optically stimulated luminescence geochronology. Major glaciations, followed by deglaciation and marine inundation, occurred during marine oxygen isotope stages 6–5e (MIS 6–5e) and stages MIS 5d–5c. These glacial sediments overlie marine sediments of Pliocene age, which are draped by fluvial sediment of a pre-Saalian age, thereby forming palaeovalley/basin fills in the post-Cretaceous topography. Till fabrics and glacial tectonics record expansions of local ice caps exclusively, suggesting wet-based ice cap advance, followed by cold-based regional ice-sheet expansion. Local ice caps over highland sites along the perimeter of the shallow Kara Sea, including the Byrranga Mountains and the Severnaya Zemlya archipelago, appear to have repeatedly fostered initiation of a large Kara Sea ice sheet, with the exception of the Last Glacial Maximum (MIS 2), when Kara Sea ice neither impacted the Chelyuskin Peninsula nor Severnaya Zemlya, and barely touched the northern coastal areas of the Taymyr Peninsula.     

南极菌Pseudoalteromonas sp．S-15-13产胞外多糖的研究及其分子鉴定

本文对影响南极细菌S-15-13生长和胞外多糖产量的主要环境因子进行了研究,同时采用16S rDNA序列分析及系统发育分析方法对其进行了分子鉴定。结果表明：菌株S-15-13最佳产糖条件为：培养时间,56h；培养温度,8℃；碳源,1．0%葡萄糖；NaCl浓度,3．0%；pH,6．0-7．0。16S rDNA序列分析和系统发育分析表明,菌株S-15-13属于假交替单胞菌属(Pseudoaltero- monas)。     

A sub-surface eddy at inertial current layer in the Canada Basin,Arctic Ocean

An Arctic Ocean eddy in sub-surface layer is analyzed in this paper by use of temperature,salinity and current profiles data obtained at an ice camp in the Canada Basin during the second Chinese Arctic Expedition in summer of 2003.In the vertical temperature section,the eddy shows itself as an isolated cold water block at depth of 60 m with a minimum temperature of-1.5℃,about 0.5℃ colder than the ambient water.Isopycnals in the eddy form a pattern of convex,which indicates the eddy is anticyclonic.Although maximum velocity near 0.4 m s-1 occurs in the current records observed synchronously,the current pattern is far away from a typical eddy.By further analysis,inertial frequency oscillations with amplitudes comparable with the eddy velocity are found in the sub-surface layer currents.After filter the inertial current and mean current,an axisymmetric current pattern of an eddy with maximum velocity radius of 5 km is obtained.The analysis of the T-S characteristics of the eddy core water and its ambient waters supports the conclusion that the eddy was formed on the Chukchi Shelf and migrated northeastward into the northern Canada Basin.     

Meteorological inventory of rain-on-snow events in the Canadian Arctic Archipelago and satellite detection assessment using passive microwave data

The spatial and temporal distributions of rain-on-snow (ROS) events across the Canadian Arctic Archipelago (CAA) remain poorly understood owing to their sporadic nature in time and space. This situation motivated the development of remote sensing detection algorithms. This paper uses a large meteorological dataset across the CAA to adapt an existing ROS-detection algorithm developed in a previous study by our group. Results highlight the spatial distribution and evolution of ROS occurrences reported since 1985 at 14 weather stations across the CAA. Results show that >600 ROS events were inventoried since 1985, for which >70% were classified as pure rain (liquid form) and 30% as mixed precipitation (solid/liquid). Of the pure rain events, 75% occurred during spring, 14% during fall, 8% during summer and <1% during winter. Such events can have significant impacts on ungulate grazing conditions through the creation of ice layers, causing serious problems for caribou calf survival, especially during the migration period. This paper introduces an adaptation for larger scale Arctic application of a detection algorithm (sensitivity analysis on the detection threshold) with an error of ~5%. The validation, however, remains limited due to a short study period and limited number of sites.     

The Mekong from satellite imagery: A quick look at a large river

Physical datasets on rivers, thousands of kilometres long, can be efficiently and rapidly acquired through satellite imagery. As large rivers commonly cross several tectonic and climatic zones, their channels are composed of a number of units, each with characteristic morphology and behaviour. Separating a large river into such units provides a framework for understanding the geomorphology of the river concerned, allowing acquisition of information for environmental impact analysis and river management.About 2500 km of the Mekong River, from the China border to the sea, has been examined with SPOT satellite images with a selection of MODIS and IKONOS scenes in support. Hydrological data of the Mekong River Commission, hydrographic maps of the Commission, and field observations have been used to verify and extend the findings from the satellite imagery. The technique provides a rapid and holistic conceptualisation of forms and functions along the derived eight-unit classification of the Mekong River. Such a framework is valuable for (1) determining selected aspects of the geomorphological behaviour of a large river system, (2) rapidly analysing project-related environmental impacts, and (3) examining the geological evolution of the river. Investigating large rivers is difficult and resource consuming, but satellite imagery provides an easy and rapid tool. The cost of the images, however, may be high as a number of them are required for this type of analysis.     

Using high resolution satellite imagery to estimate cropped area in Guatemala and Haiti

Guatemala and Haiti are two of the most food insecure nations in the Western Hemisphere. Measurements of food availability and access are instrumental in developing targeted hunger reduction strategies yet no estimates of cropped area (a critical input in the calculation of food production) at either a national or sub-national-level exist. The purpose of this research is to produce estimates of cropped area for Guatemala and Haiti using an area frame sampling approach and very high resolution (∼1 m) satellite imagery. Related research has combined livelihood data with topographic information to construct cropped area estimates in other settings using generalized additive models. We expand this approach with the inclusion of specific population variables in place of the livelihood data. We produce estimates of cropped area for the two countries and sub-national units and our results highlight the significance and complexity of incorporating explicit population characteristics into models of cropped area.     

国家需求结构演变理论及其应用——以中俄北极合作为例

首先,提出国家需求概念,在总结国家需求结构及其演变特点的基础上,提出双边关系中国家需求结构演变的三个模型：相对稳定型、合作优化型、关系紧张型。认为国家需求和人的需求一样,存在由低层次向高层次跃升的演变趋势。“低层次需求得到满足”是需求层次升级的前提条件,但这种满足具有方向性、主观性、阶段性。其次,运用国家需求结构演变模型分析了中俄北极开发合作的地缘政治环境,提出了维持中俄北极合作良好态势的对策建议：美国是中俄北极合作发生变数的能动力量,妥善处理好中美关系是重中之重;政治互信是中俄北极合作的决定性因素,加强双方在国际关系理论研究领域的合作是行之有效的政策工具;提高合作项目的透明度,向国际社会分享项目对生态环境和原住民影响的相关数据;加强战略沟通扩大共同利益,维持与美国盟友的合作伙伴关系;作为非北极国家,中国应该坚持对北极事务“有所为有所不为”的原则。最后,本研究得出如下几点结论：国家需求结构演变理论能够解释西方国际关系理论三大学派的核心观点;双边国家需求结构演变模型关注国际关系发生突变的规律性;国家需求结构演变理论能够为不同层次不同规模国家制定外交政策提供理论参考。     

A survey of SO 2, NO 2 and NH 3 concentrations in atmosphere at high latitudes and in Arctic

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Beach Ridge Geomorphology at Cape Grinnell,northern Greenland: A Less Icy Arctic in the Mid-Holocene

Geografisk Tidsskrift—Danish Journal of Geography 110(2):337–355, 2010

In northern Greenland, the Cape Grinnell beach ridge plain offers a 9,000year multi-proxy record for isostatic recovery, storm history, and the hydrological changes related to precipitation and slope evolution. The chronology of uplifted beach ridges is constrained by ten geological 14C ages on shell and sea mammal bones and eleven upper limiting ages from archaeological sites that span the last 3,000 years. Beach ridges formed under the influence of open water storms with renewed frequency and intensity ca. 3 ka and 1 ka ago. A lack of shell may reflect cooler sea surface temperatures. The presence and absence of ice can be inferred by push-features. Three intervals of heightened precipitation produced extensive fan deltas: (a) after 9 ka BP (b) prior to 4.5 ka BP and (c) during the Little Ice Age (AD 1350–1900). Active solifluction lobes and colluvia cover beach ridge deposits that are between 9 and 7 ka old.