The Sun — Major energy resource for the future

With rising standards of living, the per capita energy consumption is increasing rapidly all over the world. The limited reserves of fossil fuels may be exhausted by the middle of the next century. This crisis situation has forced technologists to turn to alternate sources of energy, like wind energy, ocean thermal energy and solar energy. All the above forms of energy are indirectly derived from solar energy. In this article a short account of the amount of solar radiation reaching the earth, its spectral distribution and its interaction with the earth’s atmosphere is presented. A brief discussion is given on hydro-power, wind-power and ocean thermal energy conversion as indirect techniques of utilization of solar energy. Solar energy can also be directly converted into heat and electricity. Techniques for such direct conversion, with special reference to photovoltaic generation of electricity, are also described in this article.     

大气甲烷源和汇的研究

甲烷是重要的温室气体之一，其单分子增温潜势约是CO2的62倍，目前大气CH4的浓度约为1．7ppm。甲烷的主要自然源包括反刍动物和一些昆虫的肠发酵及淹水土壤的有机物的厌氧分解。人类源包括煤燃烧、天然气泄漏、热带植物燃烧及垃圾填埋场．包括垃圾填埋场在内，土壤的CH4排放量约占全球CH4产生量的45％。     

Evaluating effects of atmospheric CO2 on stability of global climate: a cell-to-cell mapping approach

Atmospheric carbon dioxide concentration [CO2], incoming solar radiation and sea ice coverage are among the most important factors that control the global climate. By applying the simple cell-to-cell mapping technique to a simplified atmosphere-ocean-sea ice feedback climate model, effects of these factors on the stability of the climatic system are studied. The current climatic system is found to be stable but highly nonlinear. The resiliency of stability increases with [CO2] to a summit when [CO2] reaches 290 μL/L which is comparable to the pre-industrial level, suggesting carbon dioxide is essential to the stability of the global climate. With [CO2] rising further, the global climate stability decreases, the mean ocean temperature goes up and the sea ice coverage shrinks in the polar region. When the incoming solar radiation is intensified, the ice coverage gradually diminishes, but the mean ocean temperature remains relatively constant. Overall, our analysis suggests that at the current levels of three external factors the stability of global climate is highly resilient. However, there exists a possibility of extreme states of climate, such as a snow-ball earth and an ice-free earth.     

中国二氧化碳排放影响因素分析

在定量计算中国1991～2008年各部门终端化石燃料燃烧的CO2排放量及其变化轨迹基础上,利用LMDI模型,将CO2排放定量分解为下面五个因素：经济发展、部门结构、能源消费结构、能耗强度、碳排放系数。分别考虑这五个因素变化对中国CO2排放变化的影响。结果表明：1991～2008年间,中国化石能源燃烧CO2排放量年均增长率约为6．1％。促进中国CO2排放增长的核心因素是经济快速增长,而抑制CO2排放增长的因素主要是能耗强度下降。     

Modeling water and carbon fluxes above summer maize field in North China Plain with back-propagation neural networks

INTRODUCTION Dynamics of carbon and water vapor fluxesexchange between the atmosphere and the ecosystembiosphere, depend on complex and non-liner interplayamong physiological, ecological, biochemical andedaphic factors and meteorological conditions (Jarvis,1995; Leuning et al., 1995). There are many studiesquantifying the fluxes across different time and spacescales as well as assessing the environment con-straints on them by some kinds of biophysical orempirical models whose resul…     

近地层日最高最低气温出现的时间特征

通过探讨地理位置和地表状况等对近地层日最高、最低气温在一天中出现时间的影响,旨在教科书的基础上更为详尽地揭示它的变化规律.结果表明,气温的日变化规律主要是由太阳辐射在地表面上有规律的日变化引起的,同时也受经度、季节、地形、下垫面性质和海拔高度等因素的影响.一般而言,日最高、最低气温的出现时间是山顶早于山谷,高原早于平川,陆地早于海洋,裸地早于森林,城市早于乡村,在东区,经度越大,出现时间越早;在西区,经度越大,出现时间越迟,而且东区早于西区.但是,气温的这种周期性的日变化规律,有时也会因为雷雨天气或强冷空气等特殊天气的影响而遭到破坏.     

大气对可见光波段遥感图像影响因素的分析

太阳是可见光波段遥感主要辐射源,太阳辐射通过地球大气二次传递至传感器时,其接收到的辐射强度与太阳辐射到达地球大气层顶的辐射强度相比,已有了很大的变化,特别是传至遥感器的地面反射太阳辐射强度受到了削弱,同时大气也是遥感图像畸变的主要原因,故在遥感测量时大气层的影响应加以考虑以消除地球大气对太阳辐射产生的重要影响.基于此,本文主要探讨了可见光波段大气对遥感图像的影响因素并对其分析.     

残积土表面蒸发强度影响因素的试验分析

为确定残积土表面蒸发强度影响因素的敏感程度及其模型,以2种花岗岩残积土为例,采用自制室内蒸发试验,分析了温度、风速、太阳辐射、空气湿度、压实度、含水率对蒸发强度的影响规律,并标定了E0—θ模型的参数．结果表明,土体在高温（40℃）条件下蒸发强度约为低温（5℃）条件下的10-20倍;受太阳辐射时蒸发强度约为相同温度下不受太阳辐射时的1．5～2倍;有风条件下土表蒸发强度约为无风状态下的2～4倍;空气湿度越低蒸发强度越高;随着土壤压实度的增加,土壤蒸发强度逐渐减小,但其影响较小;土体蒸发强度随含水率降低呈减小趋势,并可近似为直线关系．因此,在确定土袁蒸发强度时应重点考虑温度、风速、空气湿度、太阳辐射、含水率的影响;E0-θ蒸发模型适用于花岗岩残积土的蒸发强度模型,相关指数均在0．9以上．     

中国非晶硅薄膜太阳能电池专利状况分析

随着人们对于化石燃料消耗殆尽的担心,各国纷纷开始寻找新的替代能源。而太阳能以其充分的清洁性、绝对的安全性、资源的相对广泛性和充足性、长寿命以及免维护性,开始受到越来越多的关注。薄膜太阳能电池作为一种新型太阳能电池,由于其原材料来源广泛、生产成本低,便于大规模生产,因而具有广阔的市场前景。     

Seasonal Behavior of Pavement in Geothermal Snow-Melting System with Solar Energy Storage

* Due to snow accumulation and ice formation onhighways, traffic accidents happen frequently in win-ter, causing great losses of economy and lives. Soroad snowremoval has been given great concern[1]. Geothermal road snow-melting system (GRSS)with solar energy storage is an effective, non-pollutionapplied sustainable energy technology developed in re-cent years. Its prominent advantage is to realize sea-sonal thermal storage and improve energy efficien-cy[2]. In Sapporo of Japan, a GRSS sys…     

红外波段大气水汽对辐射能量影响的定量分析

水汽分子对地面发射辐射能量具有强力的吸收作用,吸收使辐射能量衰减,造成传感器接收到的地面辐射亮度值下降,但水汽分子时刻运动并引起浓度发生变化,浓度的改变使地面发射辐射能穿过大气层时随之发生变化。因此该文利用物理原理,探讨了大气中水分子的运动与其浓度的关系,以及大气中水分子浓度变化引起水汽分子吸收能量和传感器获取亮度值的变化规律。     

Evolution of the atmosphere and oceans: Evidence from geological records

In Part 1 we described the early atmosphere which was rich in nitrogen and carbon dioxide and was oxygen deficient. In due course photosynthesis liberated free O2 from CO2. The abundance of O2 reached modern levels by the turn of the Proterozoic and triggered metazoan radiation. However tectonic activity exerted the ultimate control on the growth of atmospheric O2 by enhanced organic carbon burial in sediments.     

Alternative Strategies Toward Sustainable Ammonia Synthesis

As one of the world's most produced chemicals, ammonia(NH_3) is synthesized by Haber–Bosch process. This century-old industry nourishes billions of people and promotes social and economic development. In the meantime, 3%–5% of the world's natural gas and 1%–2% of the world's energy reserves are consumed, releasing millions of tons of carbon dioxide annually to the atmosphere. The urgency of replacing fossil fuels and mitigating climate change motivates us to progress toward more sustainable methods for N_2 reduction reaction based on clean energy. Herein, we overview the emerging advancement for sustainable N_2 fixation under mild conditions, which include electrochemical, photo-, plasma-enabled and homogeneous molecular NH_3 productions. We focus on NH_3 generation by electrocatalysts and photocatalysts. We clarify the features and progress of each kind of NH_3 synthesis process and provide promising strategies to further promote sustainable ammonia production and construct state-of-the-art catalytic systems.     

张北地震前的卫星热红外异常研究

地震前的热异常大多是使用极轨卫星数据来研究,例如AVHRR和MODIS数据,其时间分辨率为一天2次.由于观测时间间隔约12小时,有可能会漏掉一些异常信息.使用高时间分辨率的静止卫星数据,研究了1998年1月10日张北M s6.2级地震前热红外异常,首次精细地刻画了该热异常的形态变化.结果表明1月5日夜间热异常出现在北京西北部,随后逐渐向东南方向扩展,整体覆盖在张家口—渤海断裂带上,到1月6日凌晨消失;其温度高出周边地表温度4 K~5 K;热异常的扩张与风速、风向有关,在卫星云图上表现出明显的随风摆动现象;该异常带之下的地表的温度与周边地表温度相同,据此推断该异常出现在空中,而不是地表,这是与前人完全不同的新结论.综合以上特征,推断认为该异常可能与地下气体溢出或者异常电磁场有关,而不是岩石受力破裂所致.     

Characteristics of the Three-Dimensional Fluorescence pectra of Fossil Fuels

We have found some fluorescence characteristics of fossil fuels based on the contour maps of the tlhree-dimensional fluorescence spectra of their non-quenching samples. The common fluorescence characteristic is that themain peaks of various fossil fuels are located in the vicinity of excitation/emission wavelength pair 228nm/340nm.The diversity of fluorescence characteristics can be represented with several indexes α, K, F and R, and these index-es provide measurable parameters for division of fluorescence fingerprints of fossil fuels. The fluorescence fingerprintsof fossil fuels can be divided into five models named O,B,Q,P and G that are corresponding to condensate oil, lightoil, heavy oil, coal and natural gas, respectively. The technique has a potential application in study of environmentpollution on crude oil and geochemical exploration of fossil fuels.     

我国能源结构演进及CO2排放影响因素分析

全球气候变暖对地球生态和人类生活构成严重的威胁,成为各国政府和人民共同关注的问题。中国作为世界上最大的发展中国家,如何找到一条适合中国自己的低碳经济发展道路,是当今面临的重要问题。首先由中国50余年的能源利用情况为切入点,描述了我国一次能源结构演进状况,在定性与定量相结合的基础上系统分析了二氧化碳排放量影响因素对我国二氧化碳排放量的影响。最后得出,我国近年来的二氧化碳排放量的增长主要是由于我国经济的高速增长引起的,而能源消费结构和产业结构的改善和能源效率水平的提高可以在很大程度上降低由经济增长带来的碳排放。     

21世纪能源开发

论述了矿物燃料对大气污染造成的危害、效率低等弊端.警示在新世纪末矿物燃料面临枯竭的预言,提出了开发第二能源如太阳能和第三能源如物质内能、生物能,第四能源如太阳光压、反物质能开发研究的前景.     

Characteristics of the ThreeDimensional Fluorescence Spectra of Fossil Fuels

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风是怎样形成的？

大家都知道,风是空气流动的结果。那么是什么引起了空气的流动呢7地球上大气受热不均引起了空气的流动。太阳辐射使地面受热,大气也随之受热。地球上的一些地区整年受到阳光直接照射,一直都很温暧。另外一些地区不受阳光直接照射,因此气候比较寒冷。暖空气比冷空气轻,所以会上升。然后冷空气就运动到已经上升的暧空气的位置。空气的这种流动就形成了风。     

Exploring the atmosphere with lidars

Lidar is a powerful technique for the study of atmospheric structure and dynamics. The spatial and temporal variability of minor constituents of the atmosphere such as aerosols, dusts, clouds, water vapour, and wind speed and temperature structure of the upper atmosphere can be studied using lidar. This article describes the basic principle of lidar operation, types of laser used for the remote sensing of the atmosphere and mechanism of scattering/absorption processes when the laser interacts with the atmosphere. Part 1 gives the basics and applications of lidar. Also, one type of lidar—Mie and Rayleigh lidar is described. S Veerabuthiran is working as a research fellow in Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum. His research involves the study of aerosols, dusts, and clouds in the lower atmosphere and temperature structure in the upper atmosphere.