Function of Soils for Human Societies and Environment

This study assessed the spatial distribution of vulnerability to extreme heat in 1990 and 2000 within metropolitan Phoenix based on an index of seven equally weighted measures of physical exposure and adaptive capacity. These measures were derived from spatially interpolated climate, normalized differential vegetation index, and U.S. Census data. From resulting vulnerability maps, we also analyzed population groups living in areas of high heat vulnerability. Results revealed that landscapes of heat vulnerability changed substantially in response to variations in physical and socioeconomic factors, with significant alterations to spatial distribution of vulnerability especially between eastern and western sectors of Phoenix. These changes worked to the detriment of Phoenix's Hispanic population and the elderly concentrated in urban-fringe retirement communities.     

The Sustainable Global Energy Economy: Hydrogen or Silicon?

A sustainable global silicon energy economy is proposed as a potential alternative to the hydrogen economy. This first visualization of a silicon energy economy is based on large-scale and carbon-neutral metallic silicon production from major smelters in North Africa and elsewhere, supplied by desert silica sand and electricity from extensive solar generating systems. The resulting “fuel silicon” is shipped around the world to emission-free silicon power stations for either immediate electricity generation or stockpiling. The high energy density of silicon and its stable storage make it an ideal material for maintaining national economic functioning through security of base load power supply from a renewable source. This contrasts with the present situation of fossil fuel usage with its associated global warming and geopolitical supply uncertainties. Critical technological requirements for the silicon economy are carbon-neutral silicon production and the development of efficient silicon-fired power stations capable of high-temperature rapid oxidation of fuel silicon. A call is made for the development of research effort into these specific engineering issues, and also with respect to large-scale economical solar power generation.     

Whole mantle SH velocity model constrained by waveform inversion based on three-dimensional Born kernels

A whole mantle SH velocity model is obtained by using a unique data set and techniques. Body and surface waveforms including major and multi-orbit phases are used as a data set and are inverted by using 3-D Born kernels. The resultant model, SH18CE, reveals the different natures of the two major upwelling systems: the strong low velocity anomalies beneath Africa extend for more than 1000 km from the core–mantle boundary (CMB), whereas those beneath the Pacific are restricted to 300–400 km from the CMB. The results also show the variable natures of stagnant slabs on the 670 discontinuity around Japan: the depths of the strongest high velocity anomalies within the stagnant slabs are different region by region, which is consistent with the detailed delay time tomography model in this area.     

气候变化与多维度可持续城市化

全球大规模城市化和气候变化已是不争的事实,这是全人类需要共同面对和关注的突出问题.当前对于两者之间的复杂关系以及城市化进程如何科学应对气候变化并不清晰,从科学、管理到实践都需要进一步加强探究,以实现全球和区域可持续发展.本文首先给出全球大规模城市化和气候变化发生的基本事实,综述归纳城市化与气候变化的相互影响以及可能机制...     

MIS3晚期石笋记录的季风突变事件区域特征及全球联系

末次冰期晚期短尺度气候突变事件异常显著,对其研究有助于认识相似边界条件下气候突变规律。通过MIS3晚期亚洲季风区8支石笋记录总结分析发现,因受洞穴微环境、渗水通道、生长动力等影响,DO5~DO3事件振幅差最大可达0.9 ‰,持续时间差最大达到900年,这可能反映局地环境对同一气候信号的改造作用或与各记录分辨率及测年精度有关。同时,统计分析发现,这些短尺度DO事件具有一定相似性,其持续时间集中分布于特定范围,说明石笋同位素信号在某种程度上可以反映真实气候信号。高、低纬记录对比显示,石笋记录与低纬气候信号呈现诸多相似性,反映亚洲季风区石笋记录具有显著的"低纬特色"。因此,无论亚洲季风突变的"开关"是否归因于北高纬气候,低纬过程确实是不可或缺的"塑造者"。

     

一种新的全球海量地形实时绘制算法

本文为实现全球海量地形数据的实时可视化,提出了一种新算法。算法不使用几何数据而是利用球面特征进行地形多分辨率模型初建,然后基于视锥与节点关系对初建结果进行扩展来得到完整的地形网格。此外设计了能消除具有复杂邻接关系的节点间裂缝的拼接方式,构造了简洁的方法消除GPU32位浮点精度导致的"wob-bling"现象。实现的算法在普通微机上平均漫游速度达每秒95帧以上。     

全球增暖的另一可能原因初探

太阳是地球流体(大气和海洋等)运动的最终能量源,地球环境,尤其是气候的变化不能不与太阳活动有关.目前,普遍将全球增暖归结为温室气体含量增加所导致的温室效应的加剧,这无疑是有一定依据和有道理的.但从科学上来讲,人类活动所引起温室气体增加的影响,并非是唯一原因.基于已有的一些研究结果,从太阳活动的观点所进行的初步分析表明,太阳活动也可能是引起近世纪全球增暖的另一个重要原因.太阳活动的影响主要包括太阳辐射的直接影响和引发地磁场变化的间接影响两个方面,地球磁场的变化将可通过动力过程和热力过程而影响大气环流和气候的变化.     

全球增暖1.5/2℃下中国区域极端降水的风险变化及其影响因子

利用24个CMIP6全球气候模式的逐日降水模拟资料,基于广义极值分布(GEV)模型,研究了全球增暖1.5/2℃下我国20、50和100 a重现期极端降水的未来风险变化。可以发现,相对于历史时期(1995—2014年),全球升温1.5和2℃下极端降水发生概率风险空间分布相近,总体上呈现增加趋势,但额外增暖0.5℃将导致更高的风险。如50 a重现期极端降水,在增暖1.5/2℃下其重现期将分别变为17/14 a,极端降水将变得更加频繁。不同区域对气候变暖的响应存在区域差异,其中中国西部长江黄河中上游和青藏高原地区、中国东部长江黄河中下游及其以南地区,极端降水发生概率比达到3以上,局部更是达到5以上,为我国极端降水气候变化响应高敏感区域。进一步,基于概率分布函数从理论角度探讨了位置和尺度参数对发生概率风险的影响与贡献度量,并用于探讨极端降水气候平均态和变率变化对极端降水发生风险的影响,结果显示：位置和尺度参数的增量变化、风险变化率存在着显著的东西部差异,从而导致极端降水发生风险的影响因素存在差异。如中国西部尽管极端降水气候平均态和变率变化幅度不大,但因风险变化率较高,从而导致该区域的发生风险大...