One‐year‐long runoff forecast by a single snowpack evaluation

A degree‐day‐based model is presented for a 1 year ahead runoff forecast, with 1 day time steps. The input information is a single snowpack evaluation collected at the beginning of the snowmelt season. The snow‐cover dynamics, the key information for long‐term snowmelt forecast, are described by the snow‐line dynamics, i.e. by the movements of the downhill snowpack limit. The snowmelt volume, estimated by the snow‐line dynamics, is the exogenous input of an autoregressive transformation model. The model is calibrated by a least‐squares procedure on the basis of observed daily runoff data and the corresponding measurements of the snowpack volume (one measurement per year). A real‐world case study on the Alto Tunuyan River basin (2380 km², Argentinean Andes) is presented. The 1 year ahead Alto Tunuyan River runoff patterns, computed for both calibration and validation periods, reveal high agreement with observed streamflows. Copyright © 2004 John Wiley & Sons, Ltd.     

复杂地区观测系统分析评价的照明度函数设计

在复杂构造地区进行照明度分析,对观测系统的优化设计有着重要意义.人们对如何进行正演照明做了大量的研究工作,但是如何利用照明结果进行观测系统的优化设计并没有一个统一的标准.为了使照明度分析有一定的规范,通过文字和图形定义了炮点入射照明、检波点接收照明、共反射点面元入射照明、共反射点面元成像照明和炮点-共反射点面元-检波点...     

ldquo;2005.0中国地磁测量rdquo;地磁测点均匀性的分形表征.

为研究ldquo;2005.0中国地磁测量rdquo;地磁测点空间分布均匀性特征,基于分形理论,介绍了用分形学描述地磁三分量测点空间分布均匀性的方法．该方法将测点存在的区域以不同尺度划分为相等面积的小方块,提取不同方块区域内的三分量测点的数目与尺度,在双对数坐标中进行线性拟合,直线斜率的绝对值即为分形维数Df,并以此作为评价地磁三分量测点空间分散均匀性的指标．通过对ldquo;2005.0中国地磁测量rdquo;地磁测点均匀性的定量研究,结果表明,中国大陆区域、大陆105deg;E以东和105deg;E以西区域地磁三分量测点的分形维数Df各不相同,分别为1.748, 1.796和1.609; 105deg;E以东区域比105deg;E以西区域的分形维数更接近于其嵌入维数E=2（地球表面）,意味着105deg;E以东区域的地磁三分量测点空间分布更均匀．      

Effects of changes in winter snowpacks on summer low flows: case studies in the Sierra Nevada,California, USA

Seasonal low flows are important for sustaining ecosystems and for supplying human needs during the dry season. In California's Sierra Nevada mountains, low flows are primarily sustained by groundwater that is recharged during snowmelt. As the climate warms over the next century, the volume of the annual Sierra Nevada snowpack is expected to decrease by ~40–90%. In eight snow‐dominated catchments in the Sierra Nevada, we analysed records of snow water equivalent (SWE) and unimpaired streamflow records spanning 10–33 years. Linear extrapolations of historical SWE/streamflow relationships suggest that annual minimum flows in some catchments could decrease to zero if peak SWE is reduced to roughly half of its historical average. For every 10% decrease in peak SWE, annual minimum flows decrease 9–22% and occur 3–7 days earlier in the year. In two of the study catchments, Sagehen and Pitman Creeks, seasonal low flows are significantly correlated with the previous year's snowpack as well as the current year's snowpack. We explore how future warming could affect the relationship between winter snowpacks and summer low flows, using a distributed hydrologic model Regional Hydro‐ecologic Ecosystem Simulation System (RHESSys) to simulate the response of two study catchments. Model results suggest that a 10% decrease in peak SWE will lead to a 1–8% decrease in low flows. The modelled streams do not dry up completely, because the effects of reduced SWE are partly offset by increased fall or winter net gains in storage, and by shifts in the timing of peak evapotranspiration. We consider how groundwater storage, snowmelt and evapotranspiration rates, and precipitation phase (snow vs rain) influence catchment response to warming. Copyright © 2013 John Wiley & Sons, Ltd.     

磷矿石化学成分分析标准物质研制

磷矿的开发与综合利用不仅需要分析磷等主要元素,也需要准确地测定稀土元素和微量元素。分析测试过程需要含量适中、定值组分全的磷矿石标准物质进行质量监控,国内外现有的磷矿石标准物质无论是从定值指标还是含量梯度范围等方面均无法满足此需求。本文研制了4个不同类型磷矿石成分分析标准物质。样品采集自河北张家口钒山磷矿、贵州织金新华磷矿、云南昆阳磷矿、湖北神农架火炼坡磷矿4个典型矿区,其中张家口钒山磷矿和织金新华磷矿为含稀土的磷矿。检验结果表明样品的均匀性、稳定性良好;通过11家实验室协作定值,定值元素包括造岩主量元素、稀土元素和痕量元素共37项,其中3个组分为参考值,其余均给出标准值和不确定度。4个磷矿石标准物质形成了一个从边界品位、工业品位到磷精矿较为完整的含量系列,P_2O_5的含量分别为10.57%、18.91%、27.78%、39.40%,稀土元素总量分别为0.16%、0.11%、0.032%、0.0083%,可满足磷矿勘查、评价和综合利用开发中对标准物质的需求。     

Research on Spatial Uniformity of Rainfall Generator

In order to improve the spatial uniformity of rainfall generator to natural rainfall uniformity, according to the rotation of the test platform, a rotary test platform was designed and developed, and the slip-ring was used to solve the problem of signal transmission in the process of the rotation. Besides, the relationship between rotational speed and spatial uniformity of rainfall generator was established. The results of tipping-bucket rain gauge tested in rainfall field and flow type rainfall intensity standard device testing demonstrated that rainfall generator as the rainfall accumulation and rainfall intensity of the test environment was feasible. Results showed that with the increase of the rotate speed, spatial uniformity first increased, and then decreases, and with the decrease of the test area, different speed presented different trends. When the rotational speed was 1 RPM, test area was 1.6 m×1.6 m and 1.2 m×1.2 m, its uniformity of rainfall generator reached maximum which was bigger than 95%; with the increase of the rotate speed, tipping-bucket rain gauge of RA and RI were of good consistency under the RPM 1 and RPM 2 and the RA maximum deviation reached minimum, 0.2 mm; the average of RA under flow type rainfall intensity standard device test consisted well with rotating test platform at speed RPM 1 and 2, which illustrated the rotary testing platform was consistent with the flow type rainfall intensity standard device. It showed that the method to improve the space uniformity of rainfall generator is feasible and it could find the dynamic difference of RA.