The processes and characteristics of mass balance on the Urumqi Glacier No. 1 during 1958–2009

As a solid reservoir, a glacier can regulate regional water resources. The annual net mass balance directly reflects the fluctuation of the glacier and climate variability. Based on 51 years of mass balance observation data, the mass balance of Tianshan Mountains Urumqi Glacier No. 1 experienced a nine times positive balance fluctuation and nine times negative balance fluctuation. There were 35 and 16 negative and positive balance years, respectively. From 1996/97 to 2008/09, 12 consecutive negative balance years were observed at Tianshan Mountains Urumqi Glacier No. 1. These results demonstrate that the Urumqi Glacier No. 1 is experiencing a strong negative balance, and the strongest negative balance, -931 mm w.e. (mm water equivalent), during the observation period occurred in 2008. In addition, the cumulative mass balance reached 13,709 mm w.e. in 2008. However, in 2009, the mass balance was positive at 63 mm w.e. The equilibrium-line altitude changes with the fluctuation in the mass balance, and the effective mass balance gradient is 7.4 mm/m. In this paper, the headwaters of the Urumqi River were analyzed using meteorological data from 1958 to 2009, including the average seasonal temperature and precipitation. The results showed that the main factor associated with the mass balance variation of Glacier No. 1 is the fluctuation in the summer air temperature, followed by changes in the precipitation.     

Snow Cover Variation in the Past 45 Years (1959-2003) in the Tianshan Mountains, China

 Meteorological data at 17 weather stations in the Tianshan Mountains from 1959 to 2003 were analyzed to explore the variations in temperature and snow cover. The abrupt change test for snow depth was performed using Mann-Kendall statistic. The spatial distribution of maximum snow depth was calculated by employing GIDS interpolation and DEM data. The results show that mean temperature in winter had a rising trend at a rate of 0.44 ℃/10 a. The minimum temperature in winter increased more evidently at a rate of 0.79 ℃/10 a. The maximum snow depth has obviously deepened at a rate of 1.15 cm/10 a in the past 45 years, and it was about 16% higher than the average during 1991-2003. The Mann-Kendall statistic test of snow depth indicates that the abrupt change occurred in 1976. The maximum increment for snow cover depth occurred in Zhaoshu (Kunes) (39.3%) and Nilka (39.7%) in the west Tianshan Mountains. In contrast, the snow cover depth reduced by 17% in Barkol in the east Tianshan Mountains. There was a primary change periodicity of about 2.8 years in snow cover. In addition, snow cover days with a depth more than 10 cm increased distinctly, however, there was no obvious advance or delay in snow beginning and ending dates.     

Basal‐topographic control of stationary ponds on a continuously moving landslide

The Slumgullion landslide in the San Juan Mountains of southwestern Colorado has been moving for at least the last few hundred years and has multiple ponds on its surface. We have studied eight ponds during 30 trips to the landslide between July 1998 and July 2007. During each trip, we have made observations on the variability in pond locations and water levels, taken ground‐based photographs to document pond water with respect to moving landslide material and vegetation, conducted Global Positioning System surveys of the elevations of water levels and mapped pond sediments on the landslide surface. Additionally, we have used stereo aerial photographs taken in October 1939, October 1940 and July 2000 to measure topographic profiles of the eight pond locations, as well as a longitudinal profile along the approximate centerline of the landslide, to examine topographic changes over a 60‐ to 61‐year period of time. Results from field observations, analyses of photographs, mapping and measurements indicate that all pond locations have remained spatially stationary for 60–300 years while landslide material moves through these locations. Water levels during the observation period were sensitive to changes in the local, spring‐fed, stream network, and to periodic filling of pond locations by sediment from floods, hyperconcentrated flows, mud flows and debris flows. For pond locations to remain stationary, the locations must mimic depressions along the basal surface of the landslide. The existence of such depressions indicates that the topography of the basal landslide surface is irregular. These results suggest that, for translational landslides that have moved distances larger than the dimensions of the largest basal topographic irregularities (about 200 m at Slumgullion), landslide surface morphology can be used as a guide to the morphology of the basal slip surface. Because basal slip surface morphology can affect landslide stability, kinematic models and stability analyses of translational landslides should attempt to incorporate irregular basal surface topography. Additional implications for moving landslides where basal topography controls surface morphology include the following: dateable sediments or organic material from basal layers of stationary ponds will yield ages that are younger than the date of landslide initiation, and it is probable that other landslide surface features such as faults, streams, springs and sinks are also controlled by basal topography. The longitudinal topographic profile indicated that the upper part of the Slumgullion landslide was depleted at a mean vertical lowering rate of 5.6 cm/yr between 1939 and 2000, while the toe advanced at an average rate of 1.5 m/yr during the same period. Therefore, during this 61‐year period, neither the depletion of material at the head of the landslide nor continued growth of the landslide toe has decreased the overall movement rate of the landslide. Continued depletion of the upper part of the landslide, and growth of the toe, should eventually result in stabilization of the landslide. Published in 2008 by John Wiley & Sons, Ltd.     

The microtine distribution and its environmental significance since the Middle Pleistocene in Zhangping Caves of the Qinling Mountains

Three microtine species are recovered from the Zhangping Caves of the Qingling Mountains, namely Microtus oeconomus, Caryomys inez and Caryomys eva. They are climate-sensitive ones with different ecological habits, therefore their distribution well corresponds to environmental variations. Statistical comparison of the distribution of fossil microtines and their counterparts nowadays displays that the climate variation of the studied area and its contiguity since the middle Pleistocene are: warm and humid at 493 ka ago, cool and humid at 259 ka ago―cold and humid at 205 ka ago―cool and humid at 28 ka ago, and warm and dry at present.     

南岭地区钨矿床共（伴）生金属特征及其地质意义初探

南岭是世界上最重要的钨矿产地,南岭钨矿床中与钨共（伴）生的有色、稀有及贵金属种类很多,数量可观,也是我国重要的矿产资源。论述了南岭及其邻近地区众多钨矿床中与钨共生或伴生的锡、钼、铋、铌钽、铜、铅锌、金银、稀土等元素的不同状况和特征,其中锡、钼、铋是南岭钨矿床中最普遍最重要的共（伴）生元素,铌钽只在演化程度较高的花岗岩相关的钨矿床中伴生产出,铜、金作为钨矿床伴生金属的意义较小,而钨矿床中伴生的银、铅锌具有相当重要的意义。从元素地球化学性质、南岭的区域地背景、花岗岩演化、多期多阶段成矿作用等方面出发,分析和解释了它们之间相互共（伴）生的原因及差异性,探讨了其地质意义。     

Vegetation patterns and diversity along an altitudinal and a grazing gradient in the Jabal al Akhdar mountain range of northern Oman

Little is known about the effects of grazing on vegetation composition on the Arabian Peninsula. The aim of this study therefore was to analyse the vegetation response to environmental conditions of open woodlands along an altitudinal and a grazing gradient in the Jabal al Akhdar mountain range of Oman. The species composition, vegetation structure, grazing damage and several environmental variables were investigated for 62 samples using a nested plot design. Classification analysis and a Canonical Variate Analysis (CVA) were used to define vegetation types and to identify underlying environmental gradients. The relationship between environmental variables and diversity was analysed using correlation coefficients and a main-effects ANOVA. The plant species richness followed a unimodal distribution along the altitudinal gradient with the highest number of species at the intermediate altitudinal belt. The cluster analysis led to five vegetation groups: The Sideroxylon mascatense–Dodonaea viscosa group on grazed and the Olea europaea–Fingerhuthia africana group on ungrazed plateau sites at 2000 m a.s.l., the Ziziphus spina-christi–Nerium oleander group at wadi sites and the Moringa peregrina–Pteropyrum scoparium group at 1200 m a.s.l, and the Acacia gerrardii–Leucas inflata group at 1700 m a.s.l. The CVA indicated a clear distinction of the groups obtained by the agglomerative cluster analysis. The landform, altitude and grazing intensity were found to be the most important variables distinguishing between clusters. Overgrazing of the studied rangeland is an increasing environmental problem, whereas the plant composition at ungrazed sites pointed to a relatively fast and high regeneration potential of the local vegetation.     

西部山区县级土地利用制图的尺度选择——以四川省甘孜州为例

针对西部山区县级土地利用总体规划修编工作中暴露出的制图尺度问题,以四川省甘孜州为例,在土地利用制图成果的基础上分析了该区内石渠、甘孜、乡城不同尺度的县级土地利用制图效果。通过对比,探讨了西部山区土地利用制图适宜尺度的选择。结果表明：（1）不同尺度下县级土地利用制图在保持精度前提下,更注重经费和人力投入来合理选择尺度。（2）西部山区土地详细规划制图宜采用大比例尺（1∶5万或更大）;县级重点城镇的土地详细规划,以1∶500或1∶1 000为主。土地利用总体规划制图,州级重点县可以考虑1∶1万-1∶5万尺度,重点城镇采用1∶1 000和1∶500;一般县宜采用1∶5万-1∶10万的尺度;而其他如位于高寒牧区的县可以采取1∶10万-1∶25万的数据。     

长白山区泥炭沼泽磁化率特征及其环境意义

以长白山区泥炭沼泽为研究对象,沿不同海拔选择赤池、锦北、大牛沟、金川和哈尔巴岭5个代表性采样点。通过对沼泽垂直剖面的精细采样,利用210Pb和137Cs方法对5个剖面进行高精度定年,综合研究和分析泥炭沉积物质量磁化率沿深度垂直分布特征,进而揭示其环境意义。结果表明,长白山区泥炭沼泽磁化率在表层具有明显的富集规律,富集时间始于20世纪初,并在20世纪后期达到峰值,且其富集含量可达以下层位富集平均值的5～10倍;长白山区泥炭磁化率的表聚性特征反映了在盛行西风等自然因素作用下,大气降尘和城市扩张等多种人类活动对区域环境的影响,很好地指示了区域磁性颗粒物污染扩大和加剧趋势。     

近30年来天山托木尔峰东侧分水岭处冰川变化

利用1978年出版的航测地形图与1976年MSS影像(地形图于20世纪70年代初期测绘)、1990年landsatTM影像、2002年CBERS影像对西天山托木尔峰以东分水岭处的5条冰川近30年来的动态变化进行了研究。研究结果表明,这5条冰川在1970年代初-2002年近30年来整体上处于退缩状态,这与该地区20世纪80、90年代气温升高导致冰雪消融加速而冬季降水量基本稳定即补给来源基本不变的趋势是相符合的。这也表明,在气候变暖的趋势下,该地区冰川的补给-消融动态平衡关系被打破,冰川总体上处于退缩状态。     

天山奎屯河哈希勒根51号冰川变化监测结果分析

哈希勒根51号冰川位于新疆奎屯市以南的天山依连哈比尔尕山北坡,即奎屯河上游支流哈希勒根河源区。1999年8月,在该冰川上布设了用于冰川变化观测研究的测杆18根;同时,在冰川外围测定了2个基本控制点和3个冰川末端变化观测控制点,运用GPS和全站仪等观测技术及测杆实测等方法,对该冰川进行了末端和运动速度变化的首次观测。嗣后,每年的8月底～9月初进行了重复观测;并在2000年和2006年对该冰川进行了测量制图。通过实测资料分析并对比20世纪60年代冰川状况,结果表明:42年来冰川末端累计退缩了84.51 m,其中,1964-1999年间退缩了49.00 m,年平均退缩量为1.40 m/a;1999-2006年间退缩了35.51 m,年平均退缩量5.07m/a。冰川面积减少了0.123 km~2或8.3%,其中,1964-2000年间减少了0.083 km~2;2000-2006年间减少了0.040 km~2。明显地反映出冰川末端退缩加剧和冰川面积减少增大的趋势。冰川年平均运动速度在1.53～3.05 m/a之间,并有逐年减小的趋势。