基于遥感影像的北极海冰厚度和密集度分析方法

基于2003年7月至9月中国第二次北极科学考察所获取的大量海冰影像资料,完成了走航期间74.11°N-79.56°N,144.17°W-169.95°W范围内海冰厚度和密集度的提取。本文总结了从船侧录像中提取冰/雪厚度以及从航拍图像中提取冰密集度的方法,并描述了提高所取参数可靠性应采取的分析技术和现场调查的处理措施。本文方法具有一定的普适性,可以应用到渤海海冰和极地海冰的研究中。     

沙地渗灌系统的自动监测与控制

通过沙地渗灌系统的应用实践以及与沟灌、漫灌进行的比较研究,着重介绍了其对水分实行自动监测与控制的功能;分析了其可向植物根群区直接供给水分和养分,减少水分蒸发,保持沙地良好水分状态的优越性。     

极区海洋锚碇观测系统的设计和布放

中国第2次北极科学考察(2003年7月-9月)期间,在白令海峡和北冰洋楚科奇海布放了一套潜标和两套明标,在该次考察结束前成功回收了潜标和1套明标,获得了最长为45天的连续观测资料。通过介绍这次布放过程,对极区锚碇系统的相关技术问题进行了讨论,包括观测站位和层次的选择,锚碇系统的设计、布放步骤等,为有海冰存在的低温海域布放锚碇系统提供参考。     

极地海冰浮标的现状与应用综述

海冰是气候系统的一个重要组成要素,原位观测是获取海冰特征参数以及开展海冰变化研究的重要手段.本文主要对以海冰为目标和平台的极地浮标的发展与应用进行综合阐述,简述了国际北极浮标计划和国际南极浮标计划的发展情况,以七种常用的浮标对极区海冰、大气和上层海洋等物理参数的监测为例归纳总结了海冰浮标的系统特性和技术特点,最后结合近...     

极地海冰浮标的现状与应用综述

海冰是气候系统的一个重要组成要素,原位观测是获取海冰特征参数以及开展海冰变化研究的重要手段.本文主要对以海冰为目标和平台的极地浮标的发展与应用进行综合阐述,简述了国际北极浮标计划和国际南极浮标计划的发展情况,以七种常用的浮标对极区海冰、大气和上层海洋等物理参数的监测为例归纳总结了海冰浮标的系统特性和技术特点,最后结合近年海冰浮标的应用情况,从技术发展和研究目标等方面讨论了极地海冰浮标未来发展的方向与趋势.     

自动变形监测系统在地铁结构变形监测中的应用分析

在此次研究中,将TCA自动全站仪作为重要基础,构建自动变形监测系统,针对某城市非地铁施工阶段的地铁结构变形监测项目展开优化设计。根据实践应用结果证实,此系统稳定性与可靠性理想,能够在地铁结构变形监测中发挥作用。     

极区冰下浅表层声学监测浮标系统研发与应用

北冰洋海域的水声学研究在冰下通讯、导航定位、目标探测以及海洋环境参数反演等方面起着重要作用。而研发集成极区冰下浅表层声学监测浮标系统,获取长期连续气-冰-海界面的主要环境参数数据及冰下声学特性信息,是开展冰下水文和声学环境特性研究的重要手段。本文研究了一种极区冰下浅表层声学监测浮标系统的设计,该系统主要由主控制模块、供电模块、数据采集模块、数据远程传输模块、远程监控中心五部分组成,通过各个模块的开发与集成测试、数据的采集与传输测试、野外试验等,实现了对极区气-冰-海界面主要环境参数以及冰下浅表层声学特性参数数据的持续观测。本系统于2021年8月在中国第12次北极科学考察任务中完成现场应用,在极地低温恶劣环境下运行可靠稳定,实现了包括水声数据在内的极区各项环境观测参数的远程传输。     

一种基于特征点的无人机影像自动拼接方法

论述了当前无人机影像快速拼接可选用的方法及可行性,将稳健的SIFT算法引入无人机影像自动拼接中,分析了该算法各阶段所消耗的时间.结合无人机自身的特点对算法进行改进,在进行特征点提取前通过估算相邻影像间的重叠度缩小了搜索范围;进行尺度空间极值点探测时通过实验获取了适应于无人机影像的最优高斯核尺寸,克服了传统SIFT算法采用固定核尺寸方法的缺陷,既减少了时间消耗,又尽可能多地获得了特征点,最后应用LM方法求得精确变换矩阵,完成了影像镶嵌.实验结果表明,该算法对无人机影像拼接具有较好的适应性,在保证算法鲁棒性的同时,提高了精度和效率.     

基于海冰密集度的南极威德尔冰间湖监测与评价

海冰密集度产品在冰间湖的监测与研究中应用广泛。本文使用8种典型的被动微波遥感海冰密集度产品(NSIDC-BT-25km、NSIDC-NT2-25km、NSIDC-NT2-12.5km、NSIDC-NTBT-25km、EUMETSAT-BTBR-25km、EUMETSAT-BTBR-10km、UH-ASI-12.5km和UB-ASI-6.25km)以及5种常用的海冰密集度阈值(15%、40%、50%、60%和70%)对南极威德尔海2016—2017年出现的冰间湖进行监测,并使用形态学后处理操作对监测结果进行优化;在此基础上,对比不同阈值条件、海冰密集度反演算法以及空间分辨率差异对冰间湖面积和范围的影响,并进一步探究形态学操作对监测结果的影响。结果表明:NSIDC-NTBT-25km产品对阈值的敏感性最高,NASATeam2(NT2)算法反演的海冰密集度产品对阈值的敏感性最低,并且其监测的冰间湖面积和范围相较于Bootstrap(BT)和ARTIST Sea Ice(ASI)算法产品的监测结果整体偏小;高空间分辨率产品监测到的冰间湖开放时间更早,面积和范围更大,持续时间也更长;空间分辨率对...     

基于高分辨率遥感影像的矿山开发监测研究

矿产资源是一种不可再生的自然资源,传统的矿山监测方法已不再满足当今矿山发展的需要,遥感技术的发展为矿山的开发和管理提供了有力的技术支撑.文中以国土资源部整顿和规范矿产资源开发秩序的重点矿区——宜昌磷矿区为研究区,通过对QuickBird高分辨率遥感影像进行数据处理,分析矿山开发的标志地物并建立解译标志,将解译结果进行野外调查验证,得出该研究区矿山种类共有11类,优势矿种是磷矿,有221个开采点或开采面,其中界内开采159个,越界开采17个,无证开采28个,以采代探17个,停产或关闭76个.将解译结果和历年参考数据进行对比显示,宜昌磷矿区矿山开发秩序良好,矿山数量有所减少,但界外开采和以采代探的情况仍然存在,需要进一步加强对研究区矿山的监管,以保证矿山的可持续发展.     

The relationship between polar sea ice and the precipitation and temperature over China revealed by using SVD method

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利用高支链类异戊二烯(HBIs)重建极地海冰的研究进展

海冰的准确重建对反演气候和环境变化具有重要意义。近期研究表明,有机指标高支链类异戊二烯(HBIs)具有重建极地海冰状况的潜质,海洋沉积物中具有海冰特异性的单烯HBI(IP_(25))和双烯HBI(IPSO_(25))指标已分别成为研究北极和南极海冰变化的有力工具。本文综述了IP_(25)、IPSO_(25)的提出和验证,分析了影响HBIs生成、迁移和埋藏的诸多因素,总结了为实现精细化区分海冰状况和定量化重建海冰密集度而提出的新指标的发展及应用,并就目前存在的问题和未来研究方向进行了探讨和展望。     

Improving sea ice type discrimination by the simultaneous use of SSM/I and scatterometer data

The multi-year sea ice (MY) concentration as determined with the NASA Team algorithm (NTA) shows an increase during winter. This unrealistic feature can be reduced using combined active and passive remote sensing data, leading to a more realistic estimation of MY area. Our joint analysis of SSM/I, QuikSCATterometer (QSCAT) and meteorological data reveals events (i.e. intervals in space and time) where increased surface roughness and volume scattering, after a melt-refreezing episode, alters the passive microwave signature of the undisturbed sea ice surface. In these events, the calculation of MY and FY areas employing the NTA leads to false estimations of their amounts. It is shown that when such events occur, QSCAT backscatter values increase by more than 3 dB. This backscatter variation can be easily detected and the FY and MY area determination of the NTA can be corrected accordingly within defined event-regions. Using this method, called Simultaneous NTA, we found that in May 2000 12% of the area detected by the NTA as MY has to be corrected to FY. As a consequence, a detailed reanalysis of the 20-year passive microwave data set is suggested to more precisely compute the MY area.     

Remote monitoriug ice velocities of the polar record and the Dark Glaciers

Measurement of ice velocities of the Antarctic glaciers is very important for studies on Antarctic ice and snow mass balance. The polar area environmental change and its influences on the global environment. Conventional methods may be used for measuring the ice velocities, but they suffer from severe weather conditions in the Polar areas. Use of satellite multi-spectral and muki-temporal images makes it easier to measure the velocities of the glacier movements. This paper discusses a new method for monitoring the glacial change by means of multi-temporal satellite images. Temporal remotely sensed images in the Ingrid Christensen coast were processed with respect to geometric rectification, registration and overlay, The average ice velocities of the Polar Record Glacier and the Dark Glacier were then calculated, with the changing characteristics analyzed and evaluated. The advantages of the method reported here include promise of all-weather operation and potentials of dynamic monitoring through suitabl     

Role of sea ice in air-sea exchange and its relation to sea fog

Synchronous or quasi-synchronous stereoscopic sea-ice-air comprehensive observation was conducted during the First China Arctic Expedition in summer of 1999. Based on these data, the role of sea ice in sea-air exchange was studied. The study shows that the kinds, distribution and thickness of sea ice and their variation significantly influence the air-sea heat exchange. In floating ice area, the heat momentum transferred from ocean to atmosphere is in form of latent heat; latent heat flux is closely related to floating ice concentration; if floating ice is less, the heat flux would be larger. Latent heat flux is about 21 23 6 W·m -2, which is greater than sensible heat flux. On ice field or giant floating ice, heat momentum transferred from atmosphere to sea ice or snow surface is in form of sensible heat. In the floating ice area or polynya, sea-air exchange is the most active, and also the most sensible for climate. Also this area is the most important condition for the creation of Arctic vapor fog. The heat exchange of a large-scale vapor fog process of about 500000 km 2 on Aug. 21 22,1999 was calculated; the heat momentum transferred from ocean to air was about 14 8×10 9 kW. There are various kinds of sea fog, radiation fog, vapor fog and advection fog, forming in the Arctic Ocean in summer. One important cause is the existence of sea ice and its resultant complexity of both underlying surface and sea-air exchange.     

Summer sea ice characteristics of the Chukchi Sea

During August 1999, we investigated sea ice characteristics; its distribution, surface feature, thickness, ice floe movement, and the temperature field around inter-borders of air/ice/seawater in the Chukchi Sea. Thirteen ice cores were drilled at 11 floe stations in the area of 72°24′ 77°18′N, 153°34′ 163°28′W and the ice core structure was observed. From field observation, three melting processes of ice were observed; surface layer melting, surface and bottom layers melting, and all of ice melting. The observation of temperature fields around sea ice floes showed that the bottom melting under the ice floes were important process. As ice floes and open water areas were alternately distributed in summer Arctic Ocean; the water under ice was colder than the open water by 0.4 2.8℃. The sun radiation heated seawater in open sea areas so that the warmer water went to the bottom when the ice floes move to those areas. This causes ice melting to start at the bottom of the ice floes. This process can balance effectively the temperature fluctuating in the sea in summer. From the crystalline structure of sea ice observed from the cores, it was concluded that the ice was composed of ice crystals and brine-ice films. During the sea ice melting, the brine-ice films between ice crystals melted firstly; then the ice crystals were encircled by brine films; the sea ice became the mixture of ice and liquid brine. At the end of melting, the ice crystals would be separated each other, the bond between ice crystals weakens and this leads to the collapse of the ice sheet.     

Decadal decrease of Antarctic sea ice extent inferred from whaling records revisited on the basis of historical and modern sea ice records

In previous work, whaling catch positions were used as a proxy record for the position of the Antarctic sea ice edge and mean sea ice extent greater than the present one spanning 2.8° latitude was postulated to have occurred in the pre-1950s period, compared to extents observed since 1973 from microwave satellite imagery. The previous conclusion of an extended northern latitude for ice extent in the earlier epoch applied only to the January (mid-summer) period. For this summer period, however, there are also possible differences between ship and satellite-derived measurements. Our work showed a consistent summer offset (November-December), with the ship-observed ice edge 1 - 1.5° north of the satellite-derived ice edge. We further reexamine the use of whale catch as an ice edge proxy where agreement was claimed between the satellite ice edge (1973-1987) and the ship whale catch positions. This examination shows that, while there may be a linear correlation between ice edge position and whale catch data, the slope of the line deviates from unity and the ice edge is also further north in the whale catch data than in the satellite data for most latitudes. We compare the historical (direct) record and modern satellite maps of ice edge position accounting for these differences in ship and satellite observations. This comparison shows that only regional perturbations took place earlier, without significant deviations in the mean ice extents, from the pre-1950s to the post-1970s. This conclusion contradicts that previously stated from the analysis of whale catch data that indicated Antarctic sea ice extent changes were circumpolar rather than regional in nature between the two periods.