Relationships between Froze Damaged and Tree-measuring Factors of Huodendron biaristatum Species in Damingshan

[Objective] The aim was to provide a reference for studying the resistant ability of subtropical forest to freeze disaster and detecting the recovery and evolution of Huodendron biaristatum species after freeze disaster.[Method] Effects of the damage caused by the southern ice storm in early 2008 on Huodendron biaristatum,dominant species of evergreen broad-leaved forest on the Damingshan,were studied in the aspect of population ecology.[Result] Among the 1 090 Huodendron biaristatum individuals （DBH ≥ 1 cm）,697 individuals were victims,accounting for 63.9%.The largest part of the victims was crown breakdown,which took up 37.6%.13.0% of the victims were bent,and 10.2% of the victims were trunk broken.The least part of the victims were uprooted,accounting for only 3.1%.Different types and extent of forestry damage had remarkable differences in diameter class,tree height,crown and taper.Rates of damage and crown breakdown increased with the increase of DBH,while bent rate decreased.Rates of damage,bent and trunk broken declined slowly with the increase of tree height,while crown breakdown rate followed the normal distribution.As the crown level increased,rates of damage and crown breakdown increased,while the rate of trunk broken decreased.Individuals with high taper were more susceptible to crown damage,bending,breaking and uprooted.[Conclusion] The resistant ability of Huodendron biaristatum species to freeze disaster is affected by many factors like DBH,tree height,crown,taper,etc..Huodendron biaristatum species in Damingshan affected by those factors show various kinds of damaged types dominant by mechanical damage,but there is few individual to die.

难忘东南极

There are no national boundaries or local dwellers here. There is but a world in pure white and deep blue, enlivened only by care-free and leisurely wondering penguins, seals and whales. Here is indeed a fairy land attracting more and more tourists, and scientific investigation groups from different countries who have set up research stations to explore this unknown world. They have chosen the most severe environment to enjoy their best time of life. Among them, Bai Shanshan, a staff reporter with Sichuan Broadcasting & TV Journal is lucky enough to be the first female journalist who has twice been to the Antarctic Circle with China’s Antarctic Expedition Team. In addition to her maiden voyage along with China’s 3rd Antarctic Expedition Team in 1987 to the Antarctic Circle, she joined the team the second time in 1996 and stayed to work there for over 50 days at the Zhongshan Station from December, 1996 to February, 1997. Included in this article are the sidelights written by Bai Shanshan during her stay

Interannual and Seasonal Changes in the Ice Cover of Glacial Lakes in the Snowy Mountains of Australia

Seasonal ice cover is uncommon on Australian lakes. In the Snowy Mountains, there are five natural, seasonally ice-covered lakes including Lake Cootapatamba, the highest lake in Australia. Blue Lake is the only one of the five lakes with sufficient volume to be relatively independent of short-term changes in ambient temperature, and therefore is the lake most likely to be of use in tracking long-term regional climate change. Ice forms on Blue Lake near the winter solstice and ice-breakup occurs from late September to November. Timing of breakup is related to spring temperature and, as such, mirrors the timing of general snow thaw in the mountains. The existence of historic photographs taken of the lake at about the time of ice breakup allows for the possibility of reconstructing a history of alpine climate and in 1905 ice breakup was probably as late as mid-December.

Atmospheric Methane over the Past 2000 Years from a Sub-tropical Ice Core, Central Himalayas

A high-resolution 2ooo-year methane record has been constructed from an ice core recovered at 7200 m a.s.1, on the Dasuopu Glacier in the central Himalayas. This sub-tropical methane record reveals an increasing trend in the concentration of methane during the industrial era that is similar to observations from polar regions. However, we also observed the differences in the atmospheric methane mixing ratio between this monsoon record and those from polar regions during pre-industrial times. In the time interval o N 1850 A.D., the average methane concentration in the Dasuopu ice core was 782±40 ppbv and the maximum temporal variation exceeded 200 ppbv. The difference gradient of methane concentration in Dasuopu ice core with Greenland and Antarctica cores are 66±40 ppbv and 107±40 ppbv, respectively. This suggests that the tropical latitudes might have acted as a major global methane source in preindustrial times. In addition, the temporal fluctuation of the pre-industrial methane records suggests that monsoon evolution incorporated with high methane emission from south Asia might be responsible for the relatively high methane concentration observed in the Dasuopu ice core around A.D. 800 and A.D. 1600. These results provide a rough understanding of the contribution of tropical methane source to the global methane budget and also the relationship betweenatmospheric methane and climate change.

漫话冰山

美国影片《泰坦尼克号》上演后反响巨大。

地球面临的重大难题

人类居住的地球。在未来的年月中将面临许多重大难题,有的已有目共睹,有的却还鲜为人知。 人口 目前,世界人口已达到55亿,并以每分钟150人的速度递增着,每天净增22万,每年增加8000万。照此速度,到本世纪末,世界人口将达到63.5亿。许多专家认为,100亿是地球维持合理健康而不算奢侈生活的人口限度。这就是说,至多再过60年左右,地球上的人口就要达到人类生存的临界线,也就是说,

气象与泰坦尼克号的沉没

泰坦尼克号的沉没可算是本世纪屈指可数的大海滩,它在航海史上既创造了奇迹,又演绎了缠绵的悲剧。巨片《泰坦尼克号》又把这段历史推向舞台,并用高科技手段将其各个方面表现得可谓淋漓尽致。泰坦尼克号的一切已经变成了一个笼罩着神秘气氛的传奇。可如果从科学的观点来看待这场事件,也许会有另一种不同的感觉。有意思的是今年世界气象日的主题是“海洋、

The effect of seafloor topography in the Southern Ocean on tabular iceberg drifting and grounding

Antarctic tabular icebergs are important active components in the ice sheet-ice shelf-ocean system.Seafloor topography is the key factor that affects the drifting and grounding of icebergs,but it has not been fully investigated.This study analyzes the impact of seafloor topography on the drifting and grounding of Antarctic tabular icebergs using Bedmap-2 datasets and iceberg route tracking data from Brigham Young University.The results highlight the following points.(1) The quantitative distributions of iceberg grounding events and the tracking points of grounded icebergs are mainly affected by iceberg draft and reach their peak values in sea water with depths between 200 m and 300 m.The peak tracking point number and linear velocity of free-drifting icebergs are found in the Antarctic Slope Front(water depth of approximately 500 m).(2) The area of possible grounding regions of small-scale icebergs calved from ice shelf fronts accounts for 28%of the sea area at water depths less than 2000 m outside the Antarctic coastline periphery(3.62 million km2).Their spatial distribution is mainly around East Antarctica and the Antarctic Peninsula.The area of possible grounding regions of large tabular icebergs with long axes larger than 18.5 km(in water depths of less than 800 m) accounts for 74%of the sea area.(3) The iceberg drifting velocity is positively correlated with ocean depth in areas where the depth is less than 2000 m(R=0.85,P<0.01).This result confirms the effect of water depth variations induced by seafloor topography fluctuations on iceberg drifting velocity.