许昌麦岭水源地可开采量的水均衡法计算

根据许昌麦岭镇多年地下水动态观测资料,利用水均衡法原理,对水源地边界地质条件、补给与排泄的关系进行研究,对地下水允许开采量进行综合评价,提出水源地水量开采的建议。     

太湖生态环境演化及其原因分析

太湖地处长江下游三角洲,水域面积为2338km²,平均水深1.9m,最大水深不足2.6m,为一典型的大型浅水湖泊。太湖流域地势平坦,河网密布,河湖水力关系复杂。其主要补给径流来自西南部的天目山区及西部的宜溧河流域。每年夏天,大部分入湖洪水通过位于东太湖的太浦河及东北部的望虞河分别排入黄浦江与长江,由于出入湖河道的特殊位置,使得太湖南部的换水周期较短而北部较长。近几十年来,太湖由于污染而逐步呈现富营养化特征,污染物主要来自北部的无锡市和常州市,通过河道排入太湖北部的五里湖与梅梁湾,因此上述两地的水质较南部差。在东太湖,水产养殖对水环境的影响很大,亦呈现出富营养化特征,并殃及该地区的供水,加之该地区为太湖主要的泄洪通道,因此泥沙淤积严重,而且水生植物生长旺盛,呈现出明显的沼泽化趋势;在太湖四周地区,由于湖泊围垦和水利工程建设,其污染净化能力将降低,从而加速水环境恶化的趋势。太湖所面临这些问题,有待于强化湖泊科学管理来解决。     

旱作春小麦蒸散量测算方法的比较

采用波文比—能量平衡法和蒸渗计对农田蒸散量进行了为期3a的对比观测试验。结果表明，在半干旱雨养农业区，两者测算的农田蒸散量平均偏差为20％，波文比—能量平衡法计算值大于蒸渗计实测值，基本满足精度要求；无感热平流时两种方法所得蒸散量相关性较有感热平流时的好；在平流逆温状态下采用波文比—能量平衡法的计算误差大于非平流状态下的计算误差；由于蒸渗计隔断了与周围农田的水热交换，导致了蒸渗计测量的蒸散量较采用波文比—能量平衡法的计算值偏低，其偏差大小需要进一步试验确定。     

Relationship between solar radiation and the development and morphology of small cirque glaciers (Maladeta Mountain massif, Central Pyrenees, Spain)

Abstract Spatial and temporal variations in radiative fluxes influence glacier mass‐balance in mountain areas. The primary goal of this study was to assess differences in solar radiation on three glacial cirques located in the Maladeta Mountain massif (Central Spanish Pyrenees), and analyse their implications on glacier development and morphology. A quantitative approach is adopted to obtain the values of solar radiation (direct, diffuse and global radiation), combining several field data parameters (measured at 55 control‐points) with the solar radiation modelling package Ecosim. The data obtained confirm that the morphologies of the glacial bodies developed in the three cirques have a good correlation with the spatial variation on solar radiation inputs, favouring also the conservation (Aneto and Coronas cirques) or total vanishing (Llosás cirque) of the glacial remnants analysed here. The study shows how strongly in this Alpine‐Mediterranean context solar radiation — firstly as a function of latitude and time of year, and locally as a function of topographic slope, aspect and shadowing — controls the mass‐balance and the spatial distribution of melting in small glaciers, having an effect on the development of their morphologies.     

Spatial Dimensions of Urban Commuting: A Review of Major Issues and Their Implications for Future Geographic Research*

Modern urban transportation systems continuously challenge, and are challenged by, the changing nature of 21st‐century travel demand. Today, congestion is the norm in cities of the United States, and researchers and practitioners are seeking solutions to these problems. Urban commuting is identified as contributing to the suboptimal performance of transportation systems. This paper offers a review and critique of recent research on urban commuting, emphasizing geographical dimensions of this topic. Three broad areas of research related to urban commuting are discussed. These include (1) urban sustainability, (2) land use, and (3) geographic information systems (GIS). Major themes are examined in an effort to elicit thought on future geographic research. At the conclusion of the paper, summary remarks are provided and avenues for research are outlined.     

青藏高原对亚洲夏季风爆发位置及强度的影响

通过数值模拟,研究了青藏高原位于不同经度位置时,亚洲夏季风的爆发和演变情况,从动力和热力学角度分析了青藏高原大地形对亚洲夏季风爆发位置的影响。结果表明,青藏高原的“热力滑轮”作用引起:高原东南面热带陆地上空的偏南气流加强,降水增加,凝结潜热加强;高原西南面热带陆地上空出现偏北气流,降水减弱,陆面的感热加热加强。青藏高原对于亚洲夏季风的爆发地点有锚定的作用,在热带海陆分布的背景下,使亚洲夏季风首先在高原东南面的海洋东岸—陆地西岸爆发,并使亚洲季风降水重新分布。     

On the applicability of KirchofPs law and the principle of heat balance in thermal infrared remote sensing:A non-isothermal system

This paper proposes a basic equation of thermal radiation interaction between surface objects on the basis of the principle of heat balance in the interface. The solution of this equation takes account of the contribution of sensible heat flux and latent heat flux more completely, compared with traditional solution for surface cooling and heating processes. By the aid of the experimental data conducted in the Xiaotangshan experimental site, Beijing, both the non-applicability of Kirchoff's law and the measurability of surface emissivity in a non-isothermal system have been highlighted. Two methods called ventilation and time-delay compensations have been proposed to reduce the error induced by change of surface temperatures of non-isothermal objects during the measurement of emissivity. Based on the solution of the basic equation, this paper has analyzed and pointed out the misunderstanding in comprehension and application of Kirchoff's law published in literature.     

利用卫星遥感资料反演感热和潜热通量的研究综述

区域平均感热和潜热通量是气象、水文、生态模式中的关键物理因子，卫星遥感反演为观测区域平均感热和潜热通量提供了可能。对利用卫星遥感资料反演地气通量的方法进行了总结和评述。首先描述了现在常用的反演方法，分析了方法中的各种假定对反演结果的影响，并对不同的模式反演结果进行了比较。还指出了评价卫星反演通量的精度时需要注意的问题。最后对该领域内现存的问题与发展方向进行探讨。     

Assimilation and Fractional Crystallization Controlled by Transport Process of Crustal Melt: Implications from an Alkali Basalt-Dacite Suite from Rishiri Volcano, Japan

Mechanisms of fractional crystallization with simultaneous crustalassimilation (AFC) are examined for the Kutsugata and Tanetomilavas, an alkali basalt–dacite suite erupted sequentiallyfrom Rishiri Volcano, northern Japan. The major element variationswithin the suite can be explained by boundary layer fractionation;that is, mixing of a magma in the main part of the magma bodywith a fractionated interstitial melt transported from the mushyboundary layer at the floor. Systematic variations in SiO₂ correlatewith variations in the Pb, Sr and Nd isotopic compositions ofthe lavas. The geochemical variations of the lavas are explainedby a constant and relatively low ratio of assimilated mass tocrystallized mass (‘r value’). In the magma chamberin which the Kutsugata and Tanetomi magmas evolved, a strongthermal gradient was present and it is suggested that the marginalpart of the reservoir was completely solidified. The assimilantwas transported by crack flow from the partially fused floorcrust to the partially crystallized floor mush zone throughfractures in the solidified margin, formed mainly by thermalstresses resulting from cooling of the solidified margin andheating of the crust. The crustal melt was then mixed with thefractionated interstitial melt in the mushy zone, and the mixedmelt was further transported by compositional convection tothe main magma, causing its geochemical evolution to be characteristicof AFC. The volume flux of the assimilant from the crust tothe magma chamber is suggested to have decreased progressivelywith time (proportional to t^–1/2), and was about 3 x 10^–2m/year at t = 10 years and 1 x 10^–2 m/year at t = 100years. It has been commonly considered that the heat balancebetween magmas and the surrounding crust controls the couplingof assimilation and fractional crystallization processes (i.e.absolute value of r). However, it is inferred from this studythat the ratio of assimilated mass to crystallized mass canbe controlled by the transport process of the assimilant fromthe crust to magma chambers. KEY WORDS: assimilation and fractional crystallization; mass balance model; magma chamber; melt transport; Pb isotope     

Multi‐year water balance assessment of a newly constructed wetland,Fort McMurray,Alberta

Oil sands mining in Alberta transforms the boreal landscape of forests and wetlands into open pits, tailings ponds and overburden piles. Whereas reclamation efforts have primarily focused on upland forests, rebuilding wetland systems has recently become a motivation for research. Wetland creation and sustainability in this region is complicated by the sub‐humid climate and salinity of underlying mining material. In 2012, Syncrude Canada Ltd. completed the construction of the Sandhill Fen Watershed (SFW), a 52‐ha upland‐wetland system to evaluate wetland reclamation strategies on soft tailings. SFW includes an active pumping system, upland hummocks, a fen wetland and underdrains. To evaluate the influence of management practices on the hydrology of the system, this study reports the water balance from January 2013 to December 2014, the first 2 years after commissioning. A semi‐distributed approach was taken to examine the fluxes and stores of water in uplands and lowlands. Natural and artificial inputs and outputs were measured using a series of precipitation gauges and pumps, and evapotranspiration was quantified using three eddy covariance towers. A series of near surface wells recorded water table position. Both 2013 and 2014 were normal rainfall years, with 2013 having more and 2014 less snow than normal. In 2013, inflow/outflow from pumping was the predominant hydrological fluxes, resulting in considerable variability in water table position and storage changes throughout the summer. In 2014, the artificial addition of water was negligible, yet the water table remained near the surface in lowland locations, suggesting that wetland conditions could be maintained under current conditions. Evapotranspiration rates between uplands and lowlands were similar between years and sites, ranging from 2.2 ± 1.8 to 2.5 ± 1.2 mm/day and were largely controlled by climate. These rates were less than nearby older upland systems, suggesting that water balance partitioning will change as vegetation develops. Comparison between years and with natural systems provides insight on how management practices influence hydrologic dynamics and the overall water balance of the SFW. Copyright © 2016 John Wiley & Sons, Ltd.