高寒草旬地区沙漠化发展过程及成因分析——以黄河源区玛多县为例

遥感监测和野外调查研究结果表明：玛多县的沙漠化经历了由迅速发展到急剧逆转的过程，其中，20世纪80年代到2000年是沙漠化迅速发展的时期，沙漠化土地面积从1987年的12827．6km^2增加到16330．7km^2，达到全县土地总面积的64．7％，而在此后的6a里，沙漠化状况得以有效逆转，在2006年，沙漠化土地下降到12977．2km^2，年均逆转面积为559km^2；研究区沙漠化发生、发展的主要原因是气候变暖引起的冻土退化，以及随之引起的表土干旱化、草场退化、鼠害等；人类活动虽然在研究区沙漠化发生、发展过程中没有起到主导作用，但是可以通过以草定畜、围栏、灭鼠等措施有效控制沙漠化的发展，并使其得到逆转。     

<Emphasis Type="Italic">An Inconvenient Truth</Emphasis>: the scientific argument

The movie An Inconvenient Truth is a powerful portrayal of global warming and its impacts. The main scientific argument presented in the movie is for the most part consistent with the weight of scientific evidence, but with some of the main points needing updating, correction, or qualification. The detailed argument relies almost entirely on past and current evidence and neglects almost all information that can be gained from computer models, perhaps because such information would be difficult for a lay audience to grasp, believe, or connect with emotionally. This places an undue weight on current events as signs of ongoing climate change: some such events are apparently not related at all to climate change, while for other specific events the role of global warming is difficult or impossible to establish.     

An Inconvenient Truth: blurring the lines between science and science fiction

Al Gore’s movie An Inconvenient Truth gives a variety of unusually biased interpretations of the state of climate science and global warming theory. These cover a wide range of natural events and processes which could potentially be impacted by global warming, but which the movie misrepresents as clear examples of the human influence on climate. A few examples include the mixing up of cause and effect in his graphical portrayal of temperature and carbon dioxide variations over hundreds of thousands of years; the repeated depiction of ice calving from glaciers as a sign of global warming; the implication that Hurricane Katrina was the fault of humans; and the particularly extreme view that the Greenland ice sheet will melt, flooding coastal cities worldwide. Ultimately, all of these are related to the widespread perception that scientists have uniquely tied global warming to anthropogenic greenhouse gas emissions. The real inconvenient truth is that science has no idea how much of recent warming is natural versus the result of human activities.     

Lacustrine transgressions in the late Cenozoic Ussuri-Khanka depression (Primor’e)

In the Ussuri-Khanka depression of Primorye, the Quaternary alluvial-lacustrine and lacustrine sedimentogenesis progressed under conditions of transgressive accumulation in response to the depression tectonic subsidence and recurrent climatic fluctuations. The alluvial dams and irregular accumulation are proved to have been the leading factors of lakes’ formation within the depression. As is shown, fluctuations of the water level in limnic reservoirs depended on the climatic changes. New data considered in this work confirm the lacustrine genesis of a greater part of the Middle Pleistocene-Holocene sedimentary succession in the Khanka depression. Two transgressive phases, when the water level in the lakes rose by 1.5–2.0 m above the present one, are established for the Subboreal. The general conclusion is that the mesorhythmic structure of the sedimentary succession in the Ussuri-Khanka depression reflects the influence of climatic fluctuations in the Late Cenozoic.     

Characterizing the dynamics of soil organic carbon in grasslands on the Qinghai-Tibetan Plateau

Carbon dynamics of grasslands on the Qinghai-Tibetan Plateau may play an important role in regional and global carbon cycles. The CENTURY model (Version 4.5) is used to examine temporal and spatial variations of soil organic carbon (SOC) in grasslands on the Plateau for the period from 1960 to 2002. The model successfully simulates the dynamics of aboveground carbon and soil surface SOC at the soil depth of 0-20 cm and the simulated results agree well to the measurements. Examination of SOC for eight typical grasslands shows different patterns of temporal variation in different ecosystems in 1960-2002. The extent of temporal variation increases with the increase of SOC of ecosystem. SOC increases first and decreases quickly then during the period from 1990 to 2000. Spatially, SOC density obtained for the equilibrium condition declines gradually from the southeast to the northwest on the plateau and showed a high heterogeneity in the eastern plateau. The results suggest that (i) SOC den-sity in the alpine grasslands shows remarkable response to climate change during the 42 years, and (ii) the net carbon exchange rate between the alpine grassland ecosystems and the atmosphere increases from 1990 to 2000 as compared with that before 1990.     

安阳夏玉米生长期气候要素与产量的灰色关联分析

采用灰色关联度分析了安阳夏玉米生育期间主要气象要素与夏玉米产量的关系，明确了当地夏玉米产量在年度间的差异主要以积温为主导因素，不同生育期中的气候因素以拔节-乳熟期的光照和降水量对产量影响最大，而乳熟-成熟的降水量对产量的影响程度最弱。     

一种新的气候分型区划方法

从理论上证明统计聚类检验(CAST)与旋转经验正交函数或旋转主分量分析(REOF/RPCA)用于气候聚类分型区划的关联性。研究表明，CAST在一定的意义上可认为是REOF/RPCA用于气象要素场(气候)分型区划的理论基础。由此，作者提出CAST与REOF/RPCA相结合的一种新的分型区划方法，并用仿真随机模拟资料和实例计算验证了理论与实际结果的一致性，从而证实了这种分型区划方法的有效性及其优点。     

青藏高原臭氧低值中心的变化与我国气候的关系

利用NCEP/NCAR再分析资料、GPCP降水资料以及我国160个台站的降水资料, 研究了青藏高原臭氧低值中心偏强年和偏弱年的气候差异。结果表明，5～7月平均的青藏高原臭氧总量变化与我国当年夏季、冬季以及第二年春季的气温和降水等有明显的相关关系:在臭氧低值中心偏强年夏季, 中国绝大部分地区地面气温比多年平均偏高, 长江以南地区降水偏多, 长江以北大部分地区降水偏少, 尤其是长江中下游和黄河中下游之间的地面降水偏少特别明显。在臭氧低值中心偏强年冬季和次年春季, 中国大部分地区冬季风比多年平均弱, 使得绝大部分地区地面气温偏高。臭氧低值中心偏弱年的情况基本上与偏强年相反。因此, 青藏高原上空臭氧低值中心的变化在气候预测中是一个值得重视的因子。     

阿克苏地区大降水天气的气候特征

根据1961—2006年阿克苏地区气象观测站资料,从时空分布及地形影响等方面对局地和系统性大降水进行了分析;普查了20世纪90年代以来大降水天气资料,探讨了大降水的预报指标。结果表明:阿克苏地区大降水次数自20世纪80年代开始明显增加,50%以上发生在夏季,大降水集中出现在1～3h之内,1h降水量≥10mm一般出现在下午,傍晚是高峰期。局地大降水发生次数远多于系统大降水,有78.4%的局地大降水出现在西部和山区,东部和南部以系统大降水为主。大降水的主要影响系统是巴尔喀什湖低槽和中亚低槽,中低层切变线、辐合线的暖湿区和高能区与大降水落区有很好的对应关系。