广东近岸海域表层水中^90Sr和^137Cs的分布

本文提供了1989～1991年广东近岸表层水中~(90)Sr和~(137)Cs含量的分析结果。在调查海区,~(90)Sr含量为2.31～3.75mBq/L,平均值为3.21±0.45mBq/L。~(137)Cs含量为2.10～4.49mBq/L,平均值为3.47±0.89mBq/L。~(137)Cs/~(90)Sr放射性的比值为0.63～1.69,平均值为1.11±0.35。调查结果表明,近三年来未发现广东近岸海域有明显的人工放射性污染。目前广东近岸海水中的~(90)Sr和~(137)Cs主要仍是以往核试验所产生的放射性落下灰残余。     

Three-Dimensional Refined Modelling of Deep Structures by Using the Level Set Method: Application to the Zhaoping Detachment Fault,Jiaodong Peninsula,China

Mathematical Geosciences - The construction of fine-scale three-dimensional models of deep structures at a regional scale remains challenging. These models can be significantly benefitted by...     

高山寒漠带水文、生态和气候意义及其研究进展

高山寒漠带在青藏高原和天山地区的面积比率约为20%~30%,在高海拔山区面积分布广阔,是山区流域降水的高值区,下渗迅速,产流系数高,是山区流域的主要产流区。由于其海拔高、气温低、地形陡峭、植被稀疏,是重要的水文功能区和极端寒区生态脆弱区,附生在其中的稀疏植被和低温微生物是高山生命带的重要组成部分,对气候变化也有指示意义,但国内相关研究很少。人类活动对高山寒漠生境植被的影响比低海拔区要小,因而为我们提供了一个可以进行气候变化效应比较监测的机会。提出高山寒漠带在我国冰冻圈水文、生态和气候等方面的重要性,并对相关进展进行初步总结,建议将高山寒漠带作为一个特殊的生态、气候和水文功能区,专门进行研究。     

Effects of snow-depth change on spring runoff in cryosphere areas of China

Based on snow-depth and measured runoff data in the 19 river basins of the cryosphere areas of China, changes in cold season snow depth (CSSD) and spring runoff, and the relationship between CSSD and spring runoff were analysed. Decreasing trends in CSSD were detected mainly in the plains (plateaus), while increasing trends were found mainly in the mountainous regions. Different combinations of precipitation and temperature may be responsible for these results. The response of spring runoff to CSSD change varied greatly under climate warming. The runoff in April and May was commonly affected by CSSD, while the runoff in March was less affected by CSSD, but more by the increasing temperature causing more snowmelt in March. Due to relatively greater snow accumulation in spring, the runoff during spring was less affected by CSSD in the southern Tienshan Mountains.     

世界大洋表层水中的210Pb

本工作获得了西太平洋,东印度洋和南大西洋15个站位表层水中的溶解态210Pb和颗粒态210Pb的浓度.溶解态210Pb的浓度范围为西太平洋0.71～3.80Bq/m3;东印度洋0.42～2.15Bq/m3;南大西洋0.97～1.78Bq/m3.210Pb最大值3.80Bq/m3是在27°18′N,125°40′E(北太平洋)测得的,而最小值0.42Bq/m3是在远离澳大利亚西岸的25°18′S,111°38′E(东印度洋)测得的.在26°56′S,166°07′E(南太平洋)观测到颗粒态210Pb浓度的最大值0.35Bq/m3,而在东南印度洋颗粒态210Pb的浓度都小于0.03Bq/m3.表层水中溶解态210Pb含量一般呈现出地理性变化,其随纬度的变化与文献报道的结果很相符.     

Measurement and estimation of the summertime daily evapotranspiration on alpine meadow in the Qilian Mountains, northwest China

Research on mountain evapotranspiration (ET) is important to help understand water cycling and predict streamflow in cold regions in China. Actual daily ET was measured in two types of micro-lysimeters with depth 40 cm and diameter 31.5 cm (A) and depth 27 cm and diameter 27 cm (B), from 1 July 2007 to 10 September 2007, on an alpine meadow in the Qilian Mountains in northwest China, where Bowen ratio measuring instrument and eddy covariance system are too costly and difficult to be built in the region. The results of micro-lysimeters were used as a way to calibrate and test a number of energy balance methods and determine the pan coefficient (K _p) for a mountainous site. The results indicate that the FAO-56 Penman–Monteith offers the best performance, with RMSE of 0.61 mm day^?1, MAD of 0.46 mm day^?1, and the index of agreement near 1, followed by ASCE Penman–Monteith, Priestley–Taylor and Hargreaves–Samani, and the K _p is estimated as 0.7 for the summertime.     

How do GPM and TRMM precipitation products perform in alpine regions? A case study in northwestern China’s Qilian Mountains

Journal of Geographical Sciences - Satellite technologies provide valuable areal precipitation datasets in alpine mountains. However, coarse resolution still limits the use of satellite...     

10Be--加速器质谱法测定深海多金属结核的生长速率

采用加速器质谱法测定了东太平洋海盆ＣＣ区３个多金属结核和中太平洋海盆北部１个多金属结核中(１０)Ｂｅ的质量活度（比活度,下同）随径向深度的分布。论述了(１０)Ｂｅ－加速器质谱法测定生长速率的步骤。使用该法测得这４个多金属结核的生长速率分别为７．５,２．７,９．６和１．５ｍｍ·Ｍａ(－１),这些数据接近其他作者利用(１０)Ｂｅ法测定的世界各大洋多金属结核的生长速率。还研究了(１０)Ｂｅ法测定的生长速率与多金属结核ｍ(Ｍｎ)／ｍ(Ｆｅ)比值的关系。     

Precipitation–altitude relationships on different timescales and at different precipitation magnitudes in the Qilian Mountains

It is generally accepted that altitude is the main variable governing the spatial distribution of precipitation in the mountains. This study mainly discusses the precipitation–altitude relationships on different timescales and at different individual precipitation magnitudes in the entire study period (April 2012 to September 2015), wet season (May to September), and dry season (October to April), and tries to find a threshold to determine whether the correlation between precipitation and altitude is significant. In this study, the half-hourly data, including precipitation, wind speed, and air temperature, from April 2012 to September 2015 are obtained by six automatic meteorological stations located on the north slope of Qilian Mountains, which range from 2980 to 4484 m a.s.l., and horizontal distance is approximately 7000 m. Results indicate that (i) if all samples in the entire study period are to be investigated, the individual precipitation had to reach about 30 or 40 mm, then the sample may pass the significance test at p < 0.05 or at p < 0.01, respectively. The thresholds in wet season are same as that during entire study period. The thresholds in dry season are about 10 and 15 mm (ii) with increasing timescale, the percentage of samples that pass the test increases. However, it is until the monthly scale whether it is wet or dry season or the entire study period, the precipitation–altitude relationships have statistical significance and using the monthly or yearly scale as the time unit can be better applied to the research, which is based on the precipitation–altitude relationships.