1960-2008年额尔古纳河流域气候变化特征

为分析我国中高纬度地区的额尔古纳流域典型湿地对气候变化的响应,利用额尔古纳河流域气象站和水文站1960-2008年近50a的气象资料,分析了流域年、四季平均气温、降水量、蒸发量变化特征.结果表明：额尔古纳河流域全年及4个季节平均气温变化总体趋势为波动中上升,进人20世纪80年代中期以后,气温上升趋势进一步增强,且上游各...     

全新世早期罗布泊气候变化和耕作活动的孢粉证据

为研究全新世罗布泊地区气候变化特征、罗布泊流域耕作活动,利用东湖湖心剖面(N40°8.965’,E90°30.535’)6个有机质AMS14C结果建立年代框架,剖面以5 cm间隔采样25块做孢粉分析。孢粉分析结果显示云杉花粉有河流携带特征,云杉含量增加说明流域来水量增加,气候湿润。根据孢粉组合可将剖面划分为3个带,1、2带又分别划分为2个亚带。1带深度为57～120 cm,流域水分逐渐减少,环境逐渐恶化;2带深度为22～57 cm,乔、灌木植物花粉和草本植物花粉含量基本稳定,以草本植物花粉为主;3带深度为0～22 cm,气候湿润。其中,1A、2A亚带和3带气候相对湿润,有耕作活动。结果表明:全新世早期罗布泊流域耕作活动的出现与消亡受气候变化控制,耕作活动出现在气候湿润时期,干旱时耕作活动消失;全新世早期罗布泊流域有过干旱时段。     

中国煤炭资源综合区划研究

在研究我国煤炭资源分布规律的基础上,分析了煤炭资源分布与经济发展水平、经济区划、煤炭供需形势以及水资源、生态环境的关系。结合我国行政区划,提出了全新的我国煤炭资源综合区划方案,即三带（东部补给带、中部供给带和西部自给带）六区（东北规划区、黄淮海规划区、华南规划区、晋陕蒙宁规划区、西南规划区、西北规划区）划分方案。     

绵阳站气温均一化检验及初步分析

为了对绵阳站气温序列进行细致的均一化检验,利用1961-2010年绵阳及周边共14个观测站的年平均气温观测资料,选取了与绵阳站水平距离近、海拔高度差异小、相关性高、气温序列完整并服从正态分布、无明显突变点的4个站点,通过差值法建立被检验序列,再采用标准正态检验方法对其进行均一性检验。结果表明：1961-2010年,绵阳站的年平均气温序列共有1962、1975、1992和2002年4个断点。其中1962年和2002年这2个断点均是由于绵阳站的迁站造成,1975年断点的产生可能是因其附近年份的每日定点观测次数由4次增加到5次,1992年断点则主要是由于该年1、2、3、6月的气温偏低所致。     

长白山红松和落叶松树轮宽度年表特征

利用采自长白山红松和落叶松分布上限和下限的树轮样本,分别建立树轮宽度差值年表.结果表明:下限红松年表的平均敏感度、树轮宽度指数的年际变率、信噪比等年表特征值比上限年表的高,表明下限红松生长对环境的敏感性大于上限;落叶松年表特征值在不同海拔表现与红松相反.进一步分析发现分布上限和下限的红松生长与气候因子之间的关系不同.下...     

金沙江奔子栏-达日河段大型泥石流堆积扇的成因机制

金沙江上游奔子栏-达日河段属横断山区的干热河谷地带,河谷沿岸大型古泥石流堆积扇广泛发育,其成因却一直没有得到很好的研究.对该区瓦卡大型古泥石流堆积物进行了沉积结构、粒度、地球化学和孢粉等分析,揭示了泥石流的沉积环境及其形成过程.通过粗颗粒石英的光释光单片再生法(SAR)测年研究,获得金沙江上游奔子栏-达日河段古泥石流大规模暴发的年代为12 600～4 500 a BP.丰富的风化碎屑物源、陡峻的地形及雨季降水集中是该区古泥石流形成的主要原因.全新世早期青藏高原东南缘受西南季风加强的影响,气候趋于暖湿,季节性暴雨增加.金沙江上游干热河谷区大型泥石流堆积扇的发育年代暗示其是全新世早期西南季风加强作用下的地貌响应.从地质灾害防治的角度,由于现代气候因素导致泥石流灾害的频度和规模较小,预防该区地质灾害的重点应是防止人工砍伐树木和不合理的人工切坡导致对地表环境的破坏加剧.     

Water Requirements and Irrigation Scheduling of Spring Maize Using GIS and CropWat Model in Beijing-Tianjin-Hebei Region

Due to the over use of available water resources, it has become very important to define appropriate strategies for planning and management of irrigated farmland. In this paper, Beijing-Tianjin-Hebei (Jing-Jin-Ji) region was chosen as the case study area for its special political and economic status and its severe water problem. To achieve effective planning, the information about crop water requirements, irrigation withdrawals, soil types and climatic conditions were obtained in the study area. In the meantime, a GIS method was adopted, which extends the capabilities of the crop models to a regional level. The main objectives of the study are: 1) to estimate the spatial distribution of the evapotranspiration of spring maize; 2) to estimate climatic water deficit; 3) to estimate the yield reduction of spring maize under different rainfed and irrigated conditions. Based on the water deficit analysis, recommended supplemental irrigation schedule was developed using CropWat model. Compared to the rainfed control, the two or three times of supplemental water irrigated to spring maize at the right time reduced the loss of yield, under different scenarios.     

Exposure dating and glacial reconstruction at Mt. Field,Tasmania, Australia,identifies MIS 3 and MIS 2 glacial advances and climatic variability

Tasmania is important for understanding Quaternary climatic change because it is one of only three areas that experienced extensive mid‐latitude Southern Hemisphere glaciation and it lies in a dominantly oceanic environment at a great distance from Northern Hemisphere ice sheet feedbacks. We applied exposure dating using ³⁶Cl to an extensive sequence of moraines from the last glacial at Mt. Field, Tasmania. Glaciers advanced at 41–44 ka during Marine oxygen Isotope Stage (MIS) 3 and at 18 ka during MIS 2. Both advances occurred in response to an ELA lowering greater than 1100 m below the present‐day mean summer freezing level, and a possible temperature reduction of 7–8°C. Deglaciation was rapid and complete by ca. 16 ka. The overall story emerging from studies of former Tasmanian glaciers is that the MIS 2 glaciation was of limited extent and that some glaciers were more extensive during earlier parts of the last glacial cycle. Copyright © 2006 John Wiley & Sons, Ltd.     

Towards a Dynamical History of ‘Proto-Encke‘

There are too few active comets to account for the observed zodiacal dust. Rather we look to the collisional fragmentation and erosion of sub-kilometre meteoroids in orbit close to the ecliptic. Since 1975 we have also been aware of an apparently massive meteoroidal swarm in probable 7:2 mean motion resonance with Jupiter, seemingly at the heart of the Taurid Complex and connecting therefore with the near-ecliptic system through the so-called Štohl Stream. The notable absence of pre-1786 apparitions of 2P/Encke took on a new significance with the 1983 detection by IRAS of its asymmetric trail inside this resonance. Thus it was possible all these meteoroidal components were ultimately derived from a continuously eroded, substantially dormant, librating progenitor within the trail whose more volatile inclusions are exposed from time to time and expelled either singly or severally as independent comets. A Taurid progenitor of this kind (proto-Encke) dominating the inner Solar System environment probably then accounts for most of the recorded enhancements of the larger meteoroid flux to Earth, including ‘Tunguska’ bodies as well. Terrestrial dust insertions which control mean temperature and hence climate are also inferred based upon the libration and nodal precession half-periods of proto-Encke (∼0.2 kyr, ∼2.5 kyr respectively) albeit the longer of these cycles was not at first evident in the terrestrial record (Asher & Clube 1993). Recently however this cycle appears to have been confirmed as a significant (long term) global warming/meridional atmospheric circulation / iceberg calving cycle with the correct phase producing the so-called mini-Heinrich and Heinrich events of the Holocene and late Upper Pleistocene respectively, i.e., during the past ∼60 kyr BP. The comparative stability of this terrestrial cycle, in contrast with the weakness of the observed resonance, suggests a fairly recent diversion therefore from a much stronger sungrazing 7:2 Jovian resonance in which proto-Encke's and Jupiter's longitudes of perihelion are related by ϖ pE ≈ ϖ J or ϖ J + π. Thus both the Hephaistos Stream and the Taurid Complex could have formed together during a recent close planetary encounter, say with Mercury ∼5 kyr BP. It follows that we envisage a single large progenitor in 7:2 Jovian sungrazing resonance for 50 kyr or so which undergoes repeated tidal stress: a continuous dust-induced major glaciation is thus sustained on Earth for most of this dynamical timescale before a disruptive planetgrazing event finally brings its sungrazing status to an end and produces the present meteoroidal complex. This evolutionary sequence almost certainly requires that the original sungrazing stream still exists (without its source): a potentially significant fact because it may have a direct bearing on both the observed zodiacal bands and the original progenitor orbit as well as the known periodic variation of solar radiance and convected magnetic field, of possible relevance to the solar cycle. While these aspects have to be further explored, the purpose of the present investigation is to describe some preliminary modelling with a view to inferring the likely dynamical history of proto-Encke. This revised version was published online in July 2006 with corrections to the Cover Date.     

Techniques for assessing the climatic sensitivity of river flow regimes

Regimes are useful tools for characterizing the seasonal behaviour of river flow and other hydroclimatological variables over an annual cycle (hydrological year). This paper develops and tests: (i) a regime classification method to identify spatial and temporal patterns in intraannual hydroclimatological response; and (ii) a novel sensitivity index (SI) to assess river flow regimes' climatic sensitivity. The classification of regime shape (form) and magnitude considers the whole annual cycle rather than isolating a single month or season for analysis, which has been the common approach of previous studies. The classification method is particularly useful for identifying large‐scale patterns in regimes and their between‐year stability, thus providing a context for short‐term, small‐scale process‐based research. The SI provides a means of assessing the often‐complex linkages between climatic drivers and river flow, as it identifies the strength and direction of associations between classifications of climate and river flow regimes. The SI has the potential for application to other problems where relationships between nominal classifications require to be found. These techniques are evaluated by application to a test data set of river flow, air temperature and rainfall time‐series (1974–1999) for a sample of 35 UK river basins. The results support current knowledge about the hydroclimatology of the UK. Although this research does not seek to yield new, detailed physical process understanding, it provides perspective at large spatial and temporal scales upon climate and flow regime patterns and quantifies linkages. Having clearly demonstrated the regime classification and SI to be effective in an environment where the hydroclimatology is relatively well known, there appears to be much to gain from applying these techniques in parts of the world where patterns and associations between climate and hydrology are poorly understood. Copyright © 2004 John Wiley & Sons, Ltd.