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1.
Amery冰架DEM及其海洋冰分布研究 总被引：1，自引：0，他引：1
Amery冰架是东南极最大的冰架。利用克里格插值法对Amery冰架地区的ICESat激光高度计数据进行空间插值,建立该地区的DEM。依据流体静力学平衡原理构建Amery冰架的冰厚度图,结合冰雷达测厚数据,获得了海洋冰的空间分布。结果显示Amery冰架下的海洋冰主要位于西北部,体积为2.38×1012m3,约占冰架总体积的5.6%,冰架最大厚度为230 m。 相似文献
2.
Erich Heucke 《Geografiska Annaler: Series A, Physical Geography》1999,81(4):603-609
The purpose of this contribution is to explain the characteristics of a newly developed ice drill which is particularly geared to the needs of glaciologists. It is primarily designed for drilling holes for ablation stakes and for measuring water levels or temperatures in firn areas. Its distinguishing features are its light weight, making it easy to carry even over long distances, and the variety of tasks to which it can be adjusted. Furthermore, it is easy to operate even by one person.
Water is heated in a boiler by two gas flames to produce steam, which flows through an insulated hose to a nozzle. When the valve is opened the issuing steam condenses, and the heat released in the process melts the ice. The heater is constructed in such a way that it can easily be adapted to any form of gas supply locally available. It can be used for drilling in ice as well as in firn. The maximum drilling depth is 13 m in ice and 30 m in firn; hole diameters range from 25 to 45 mm. Mean drilling time is 16 min for 6 m, 35 min for 12 m in ice. The total weight is somewhat less than 16 kg, including all parts needed for drilling holes of 10 m in depth as well as the gas supply for one day. In recent years, devices of this type have been used successfully by scientists in various glaciated regions. 相似文献
Water is heated in a boiler by two gas flames to produce steam, which flows through an insulated hose to a nozzle. When the valve is opened the issuing steam condenses, and the heat released in the process melts the ice. The heater is constructed in such a way that it can easily be adapted to any form of gas supply locally available. It can be used for drilling in ice as well as in firn. The maximum drilling depth is 13 m in ice and 30 m in firn; hole diameters range from 25 to 45 mm. Mean drilling time is 16 min for 6 m, 35 min for 12 m in ice. The total weight is somewhat less than 16 kg, including all parts needed for drilling holes of 10 m in depth as well as the gas supply for one day. In recent years, devices of this type have been used successfully by scientists in various glaciated regions. 相似文献
3.
<正> The reconstruction of air trapped in ice cores provides us the most di-rect information about atmospheric CH_4 variations in the past history.Ice corerecords from the“Three Poles(Antarctica,Greenland and Tibetan Plateau)”re-veal the detailed fluctuations of atmospheric CH_4 concentration with time and areallowed to quantify the CH_4 differences among latitudes.These data are indis-pensably in the farther study of the relationship between greenhouse gases andclimatic change,and of the past changes in terrestrial CH_4 emissions.Ice coresreconstruction indicates that atmospheric CH_4 concentration has increased quicklysince industrialization,and the present day's level of atmospheric CH_4(1800 pp-by)is unprecedented during the past Glacial-Interglacial climate cycles. 相似文献
4.
The Antarctic climate system involves many complex interactions between the atmosphere, oceans and ice and is sensitive to variations in these components. Ice shelves represent the ice–ocean–atmosphere interface of the Antarctic continent and are therefore very important indicators of climate change in the region. The Amery Ice Shelf is the largest ice shelf in East Antarctica and has been the focus of many scientific research projects over the past 50 years. This paper presents a history of the use of spatial science techniques from basic survey equipment to satellite systems in Australian research projects based on the Amery Ice Shelf (and surrounding glaciers) since 1955. The application of these spatial data to projects based primarily in the fields of geodesy, glaciology, climatology, and oceanography has allowed the measurement and monitoring of the physical, dynamic and environmental characteristics of this large and remote region. This new information provides scientists with a better understanding of the ice shelf/ocean/atmosphere system allowing future monitoring to observe the effects of global climate change. 相似文献
5.
A. K. Tulokhonov E. Zh. Garmaev Yu. B. Bashkuev Yu. L. Lomukhin V. B. Khaptanov M. G. Dembelov M. V. Slipenchuk B. Ch. Dorzhiev O. N. Ochirov 《Geography and Natural Resources》2018,39(1):39-45
Presented are the results of the winter 2014 radiophysical expedition, within the framework of which the Baikal ice cover was investigated by electromagnetic methods. The primary objectives the expedition were to detect irregularities in the ice cover, such as cracks and thawing steamed holes in the ice, and to determine the ice thickness and structure in the area of the thawing holes by the GPR sounding method. We used in the experiments the OKO-2 ground-penetrating radar (GPR) of the decimeter band and the nanosecond radar with the wavelength of 3 cm. The measurements were made carried out from the Khivus hovercraft and from the UAZ automobile. The ice thickness of Lake Baikal was determined by non-contact electromagnetic measurement methods. Radargrams of reflected signals from the ice cover are presented. Radar patterns of reflected signals from artificial irregularities of the ice cover were obtained by the short-pulse radar method. The concept of radiophysical monitoring is suggested, which provides a means of determining the ice cover parameters of a water body with high spatial resolution. We present an integral approach to investigating the conditions of the ice cover in order to integrate different physicochemical methods for diagnosing the objects studied. A further development of the concept of integrated ice cover research, and the creation of the monitoring network involves solving a number of scientific and engineering tasks that include developing physical models and information and measurement systems as well as the rationale for an integrated monitoring network. 相似文献
6.
湖冰遥感监测方法综述 总被引：4，自引：2，他引：2
本文综述了多光谱和微波数据监测湖冰冻结、消融及冰厚的方法,并比较了各种方法的优缺点,最后运用MODIS和AMSR-E监测了纳木错2007/2008冬半年冰情.湖冰监测方法主要有阈值法和指数法.阈值法是根据冰水反射率、温度、后向散射系数等特征因子的不同直接区分冰水.精度较高,误差在5天以内.指数法主要是根据冰水波谱特性和极化特性.做波段运算后间接区分冰水.冰厚监测常采用经验公式法,用实测数据与反射率、极化比、亮温等建立关系式反演整个湖泊冰厚,此方法适用于特定的某个湖泊.冰厚识别是湖冰监测的难点,主动微波比多光谱数据更适合监测冰厚.从数据本身来讲,热红外、被动微波等高时间分辨率数据比可见光、主动微波等高空间分辨率影像更适合监测大面积湖泊冰情.基于多源遥感数据,发展自动反演算法将是湖冰遥感监测发展趋势之一. 相似文献
7.
JAN LUNDQVIST 《Polar research》1989,7(2):109-117
Knowledge about the Quarternary geology of the Australian sector of Antarctica is very incomplete. Scattered observations of glacial deposits in that area, made during the ANARE 6 expedition in 1987, indicate that the inland ice had formerly a considerably wider extension than today. The ice was more than 200 m thicker, probably of the order 1, 000m. This maximum stage cannot yet be dated, but conditions seem to favour a late Wisconsin-Weichselian maximum age. However, a much higher age cannot be excluded. 相似文献
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This paper reviews the evidence and history of glacier fluctuations during the Little Ice Age (LIA) in the Canadian Rockies. Episodes of synchronous glacier advance occurred in the 12th–13th, early 18th and throughout the 19th centuries. Regional ice cover was probably greatest in the mid-19th century, although in places the early 18th century advance was more extensive. Glaciers have lost over 25% of their area in the 20th century. Selective preservation of the glacier record furnishes an incomplete chronology of events through the 14th–17th centuries. In contrast, varve sequences provide continuous, annually resolved records of sediments for at least the last millennium in some highly glacierized catchments. Such records have been used to infer glacier fluctuations. Evaluation of recent proxy climate reconstructions derived from tree-rings provides independent evidence of climate fluctuations over the last millennium. Most regional glacier advances follow periods of reduced summer temperatures, reconstructed from tree rings particularly ca. 1190–1250, 1280–1340, 1690s and the 1800s. Reconstructed periods of higher precipitation at Banff, Alberta since 1500 are 1515–1550, 1585–1610, 1660–1680 and the 1880s. Glacier advances in the early 1700s, the late 1800s and, in places, the 1950–1970s reflect both increased precipitation and reduced summer temperatures. Negative glacier mass balances from 1976 to 1995 were caused by decreased winter balances. The glacier fluctuation record does not contain a simple climate signal: it is a complex response to several interacting factors that operate at different timescales. Evaluation of climate proxies over the last millennium indicates continuous variability at several superimposed timescales, dominated by decade–century patterns. Only the 19th century shows a long interval of sustained cold summers. This suggests that simplistic concepts of climate over this period should be abandoned and replaced with more realistic records based on continuous proxy data series. The use of the term LIA should be restricted to describing a period of extended glacier cover rather than being used to define a period with specific climate conditions. 相似文献
10.
Surface melt has great impacts on the Greenland Ice Sheet （GrlS） mass balance and thereby has become the focus of significant GrlS research in recent years. The production, transport, and release processes of surface meltwater are the keys to understanding the poten- tial impacts of the GrlS surface melt. These hydrological processes can elucidate the following scientific questions： How much melt- water is produced atop the GrlS？ What are the characteristics of the meltwater-formed supraglacial hydrological system？ How does the meltwater influence the GrlS motion？ The GrlS supraglacial hydrology has a number of key roles and yet continues to be poorly understood or documented. This paper summarizes the current understanding of the GrlS surface melt, emphasizing the three essential supraglacial hydrological processes： （1） meltwater production： surface melt modeling is an important approach to acquire surface melt information, and areas, depths, and volumes of supraglacial lakes extracted from remotely sensed imagery can also provide surface melt information; （2） meltwater transport： the spatial distributions of supraglacial lakes, supraglacial sarams, moulins, and crevasses demonstrate the characteristics of the supraglacial hydrological system, revealing the meltwater transport process; and （3） meltwater release： the release of meltwater into the englacial and the subglacial ice sheet has important but undetermined impacts on the GrlS motion. The correlation between surface runoff and the GrlS motion speed is employed to understand these influences. 相似文献
11.
乾宁古冰帽于1982年被作者发现,发育于大雪山顶部的夷平面上,海拔高度为4300～4400 m,地理坐标为101°14′～101°30′E,30°20′～30°38′N,是青藏高原位置最东、海拔最低的一个更新世古冰帽,生成环境独特。它还具有中心区缺少冰蚀过程遗迹的独特性质,其机理在于冰帽中心区冰层太薄、动能低、冰体侵蚀力弱,而边缘带冰层增厚。侵蚀力也增强。它的发现对进一步探讨青藏高原第四纪冰川问题具有重要意义。 相似文献
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It is well known that varying of the sea ice not only in the Antarctic but also in the Arctic has an active influence on the globe atmosphere and ocean. In order to understand the sea ice variation in detail, for the first time, an objective index of the Arctic and Antarctic sea ice variation is defined by projecting the monthly sea ice concentration anomalies poleward of 20°N or 20°S onto the EOF (empirical orthogonal function)-1 spatial pattern. Comparing with some work in former studies of polar sea ice, the index has the potential for clarifying the variability of sea ice in northern and southern high latitudes. 相似文献
14.
小冰期气候的研究进展 总被引：18，自引：5，他引：13
小冰期是近2ka来的一个重要气候事件,又是目前全球变暖的背景事件,已成为古气候和古环境研究的热点。对此,科学工作者已经做了大量的研究。本文广泛综合前人研究的成果,介绍了小冰期的概况,认为1450-1890年是小冰期的时限,在此期间有三次冷期和两次暖期。冷期发生在1450-1510年、1560-1690年和1790-1890年,其中第二次冷期表现最甚;暖期发生在1510-1560年和1690-1790年。太阳活动和火山活动是小冰期气候变化的主要因素。并重点从冰芯、树轮、湖泊沉积、历史文献和沙漠地层等方面综述了近年来国内外对小冰期气候变化的研究现状。 相似文献
15.
This paper outlines the fundamental roles sea ice plays during the spring Arctic climate, and it demonstrates the use of passive microwave remote sensing in measuring climatically important sea ice variables during the spring transitional period. It discusses the theoretical concepts underlying passive microwave remote sensing of sea ice, and it summarizes the historical use of satellite microwave radiometry in the Arctic region. In addition, this paper discusses the derivation of climatically important sea ice variables, including sea ice extent, concentration, multiyear ice fraction, and snow melt onset, with additional comments on the precision and accuracy of the remote sensing estimates. It also discusses interannual trends in sea ice extent and presents interannual trends in snow melt onset dates. Finally, this paper provides a brief discussion on the future directions in passive microwave remote sensing of climatically important sea ice variables during the spring transitional period. 相似文献
16.
《The Professional geographer》2013,65(2):315-322
This paper outlines the fundamental roles sea ice plays during the spring Arctic climate, and it demonstrates the use of passive microwave remote sensing in measuring climatically important sea ice variables during the spring transitional period. It discusses the theoretical concepts underlying passive microwave remote sensing of sea ice, and it summarizes the historical use of satellite microwave radiometry in the Arctic region. In addition, this paper discusses the derivation of climatically important sea ice variables, including sea ice extent, concentration, multiyear ice fraction, and snow melt onset, with additional comments on the precision and accuracy of the remote sensing estimates. It also discusses interannual trends in sea ice extent and presents interannual trends in snow melt onset dates. Finally, this paper provides a brief discussion on the future directions in passive microwave remote sensing of climatically important sea ice variables during the spring transitional period. 相似文献
17.
This paper briefly reviews the cause of the striping and then develops a tapered (Chebwin & Kaiser) window finite impulse response (FIR) filter and a constrained least squares FIR filter by reason of the striping of ASTER satellite data . Both filters minimize the stripes in the visible data and simultaneously minimize any distortion in the filtered data. Finally, the results obtained by using these new filtering methods are quantitatively compared with those produced by other destriping methods. 相似文献
18.
中国热带西部的小冰期 总被引：2，自引：1，他引：1
中国热带以约105°E为界分为东部和西部。热带西部主要是滇南地区。按照史书记载的25个冷冬降雪年份,小冰期为1498-1896年,期间有3个寒冷阶段(1498-1550年、1694-1826年、1868-1896年)和2个相对温暖阶段。热带西部的小冰期比东部地区历时短,寒冷阶段滞后,影响范围较小。小冰期时水旱灾害频仍。小冰期的寒冷阶段与太阳黑子活动的平静期有一定的相关性。热带东、西部小冰期的差异,主要是由于东部受东亚季风影响,西部受南亚季风影响。 相似文献
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