Simulation study of China’s net primary production

Spatial and temporal distribution of vegetation net primary production （NPP） in China was studied using three light-use efficiency models （CASA, GLOPEM and GEOLUE） and two mechanistic ecological process models （CEVSA, GEOPRO）. Based on spatial and temporal analysis （e.g. monthly, seasonally and annually） of simulated results from ecological process mechanism models of CASA, GLOPEM and CEVSA, the following conclusions could be made： （1） during the last 20 years, NPP change in China followed closely the seasonal change of climate affected by monsoon with an overall trend of increasing; （2） simulated average seasonal NPP was： 0.571±0.2 GtC in spring, 1.573±0.4 GtC in summer, 0.6±0.2 GtC in autumn, and 0.12±0.1 GtC in winter. Average annual NPP in China was 2.864±1 GtC. All the five models were able to simulate seasonal and spatial features of biomass for different ecological types in China. This paper provides a baseline for China＇s total biomass production. It also offers a means of estimating the NPP change due to afforestation, reforestation, conservation and other human activities and could aid people in using for-mentioned carbon sinks to fulfill China＇s commitment of reducing greenhouse gases.     

Water Quality Management of Beijing in China

IntroductionBeijing is the national capital of China,andthe capital of Beijing Municipality. The city islocated on the North China Plain,approximately1 50 km Northwest of the Bohai Sea at a north-latitude of40°.The municipality is approximately1 60 0 0 km2 in size,of which 2 / 3is mountainousarea encircling the western,northern and easternsides of the city. From the 1 990 census,the totalpopulation was 1 2 .9million,with 6. 4millionliving in urban areas,5.2 million living in the city,and …     

Mathematical Simulation of Dynamic Heat Transfer in a Human-Clothing-Environment System

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Filling Simulation of Three-dimension Braided Composite in Resin Transfer Molding

This paper measured permeability of three-dimension braided preform by radial technology. The results show that principal permeability tensor coincided with their braiding axial direction. The software of one dimensional flow filling mold was designed using Visual C ＋ ＋ language. Filling time is predicted and validated. The result showed that the filling time of the mold centerline agrees with the prediction value. The filling time of the mould edge is shorter than that of the prediction. An actual plate of 3 - D braided preform / modified polyarylacetylene composite is produced according to prediction value and validation analysis.     

Water Pricing Policy in Tarim Basin of China

1　Necessity for Study of WaterPricingChina ranks the thirteenth among the countrieswith serious watershortage problems in the world.The average water amount owned per person isonly 2 4 0 0 m3/ year,which is about 1 / 4of theworld average.But the problem is not only theshortage of water but also its uneven distributionbetween different time periods and regions inChina.Serious water shortage problems occur insome areas such as North China and NorthwestChina(including Hebei,Inner Mongolia,G…     

Preliminary estimation of the organic carbon pool in China’s wetlands

Accurate estimation of wetland carbon pools is a prerequisite for wetland resource conservation and implementation of carbon sink enhancement plans.The inventory approach is a realistic method for estimating the organic carbon pool in China’s wetlands at the national scale.An updated data and inventory approach were used to estimate the amount of organic carbon stored in China’s wetlands.Primary results are as follows:(1) the organic carbon pool of China’s wetlands is between 5.39 and 7.25 Pg,accounting for 1.3%-3.5% of the global level;(2) the estimated values and percentages of the organic carbon contained in the soil,water and vegetation pools in China’s wetlands are 5.04-6.19 Pg and 85.4%-93.5%,0.22-0.56 Pg and 4.1%-7.7%,0.13-0.50 Pg and 2.4%-6.9%,respectively.The soil organic carbon pool of China’s wetlands is greater than our previous estimate of 3.67 Pg,but is lower than other previous estimates of 12.20 and 8-10 Pg.Based on the discussion and uncertainty analysis,some research areas worthy of future attention are presented.     

Perspectives of China’s Wind Energy Development

Wind energy is a kind of clean renewable energy, which is also relatively mature in technology, with largescale development conditions and prospect for the commercialization. The development of wind energy is a systematic project, involving policy, law, technology, economy, society, environment, education and other aspects. The relationship among all the aspects should be well treated and coordinated. This paper has discussed the following relationships which should be well coordinated： relationship between wind resources and wind energy development, relationship between the wind turbine generator system and the components, relationship between wind energy technology and wind energy industry, relationship between off-grid wind power and grid-connected wind power, relationship between wind farm and the power grid, relationship between onshore wind power and offshore wind power, relationship between wind energy and other energies, relationship between technology introduction and self-innovation, relationship among foreign-funded, joint ventured and domestic-funded enterprises and relationship between the government guidance and the market regulation, as well as giving out some suggestions.     

A Milestone in China’s Space History —The White Paper on China’s Space Activities

The white paper document titled“China’s Space Activities”,released in November２０００by the Information Office of the State Council,represents the first time for China to fully,systematically and publicly introduce to the world China’s space development strategy and concerned policies．Its release is a milestone event in the country’s space history,bearing great importance and profound influence to its future space efforts．The paper here describes the shaping processes of some important new ideas and concepts,including the connotative meaning of“space activities in a broad sense”and the roles and positions of different sectors in such activities．It also briefly discusses related policies concerning the country’s space development and short term concepts and plans on its civil space activities．     

China’s Geographic Foundations

我想在中等以上学校教授地理的人和其他需要地理材料的学者不免常常感觉到我们缺乏一本良好的中国地理概论。固然,科学的地学材料不能算不多,但卷帙浩瀚,初学者往往望洋兴叹,中国许多中等以上学校华业生对於本国地理观念的薄弱,这恐怕是一个主要原因吧(1)。集成的叙述虽然有,但少有可以叫我们满意的,英文方面Archibald　Little之“TheFar East”在通俗地理中尚为简约明畅在英美久负盛名,但该书成於1905许多材料均嫌陈旧,且卅年来中国地学研究颇有进步已经把许多从前欧美地学家的结论推翻或改正了,再则中国经过了二十多年的革命也不能和卅…     

南水北调中线工程对湖北省的影响分析

南水北调中线工程是指从汉江的丹江口水库引水供给华北地区,同时考虑鄂、豫两省汉江唐白河流域和淮河流域的需水要求的战略性工程。汉江中下游地区是湖北省的粮仓和重要的产业基地,是汉江流域经济发展 的中心,但由于调水的影响,汉江丹口以下的流量及季节性分配将发生变化,航运、水质、农业灌溉、工业生产以及城市发展等将受到不同程度的影响,直接关系到湖北省在21世纪的持续发展。     

南水北调中线穿黄隧洞工程盾构施工关键技术

南水北调中线穿黄隧洞工程盾构施工具有地质条件复杂、大埋深、高外水压力、长线路、大直径等施工特点及其相应的技术难题.经过在施工实践中的创新与实践,在泥浆配置技术、掘削面稳定控制技术、突破规范的壁后注浆技术、高外水压力条件下的盾构施工防渗技术、端头地层加固技术、大埋深/高外水压力下的带压进舱技术、盾构掘进姿态控制技术、精密的长距离竖井联系测量技术、长距离泥水输送技术、大坡度盾构掘进技术等方面取得了突破与进展,确保了工程的顺利实施.穿黄盾构工程的各项技术指标均达到了理想的效果,相关工程施工技术可供类似工程参考和借鉴.     

再论南水北调西线工程替代方案

针对国内对兴建南水北调西线工程提出的种种质疑以及其所存在的无法回避的某些弊端问题,再次提出替代方案,认为鸭绿江水南调工程、湖北长湖调水工程具有更好的可行性、优越性。通过替代方案,改西线调水为调电,不仅能够为华北地区、黄河中上游地区提供较多的水资源,有利于西北地区发展节水经济和西南地区保护生态环境,而且会使受益地区产生更大的经济、社会和生态效益。     

南水北调中线干线智慧输水调度的思考

根据智慧水利和数字孪生工程建设的相关要求,基于现代人工智能技术和水利专业知识,结合中线干线工程输水调度任务和职责,尝试提出中线干线智慧输水调度的定义和基本功能要求。在分析智能和智慧之间逻辑关系的基础上,分别从感知智能、认知智能、决策智能系统地讨论了中线干线智慧输水调度的关键技术、存在的不足和提升建议。调度感知智能方面,提出接触式与非接触式相结合、机器视觉与传统传感相结合、自动采集和人工巡查相结合的数据采集体系,构建基于多源数据融合的数据清洗方法;调度认知智能方面,提出机理研究结合数据挖掘的建模思路,分别从预报、预警、预演、预案的角度,全面总结分析输水调度关键技术和建模要求,构建前馈调控策略模型、水力模拟仿真模型、调度预报预警模型、参数自适应模型等;调度决策智能方面,提出以模拟推演为前馈、以实时监测为反馈的调控思路,建立基于滚动决策修正、实时响应的自动化输水调控策略,构建多目标优化调度模型。     

南水北调中线输水渠道中分水口的影响

为研究南水北调中线输水渠道中分水口流量变化对干渠的影响特征,选取天津分水口为例,采用一维Saint-Venant数学模型模拟计算了该分水口各种分水状态下干渠中的水流过渡过程。提出采用虚拟渠道等效糙率法来模拟渠道中各类型的输水建筑物的影响。得出该分水口关闭时间超过33.6h会导致紧邻下游端的西黑山节制闸前水位出现漫顶。分水口前水位下降速度与分水口流量变率呈线性变化关系,并给出了其拟合公式。     

南水北调中线水源区生态补偿研究现状与展望

目的 探寻南水北调水源区生态补偿研究存在的问题,寻找建立水源区补偿机制的思路.方法 通过查阅大量的文献资料,进行理论分析.结果 南水北调中线水源区生态建设预期的资金来源几乎全部依靠中央财政转移,缺乏市场运营机制和多渠道融资途径.结论 国家应将水源区生态环境建设纳入西部大开发的统筹规划,借鉴国内外补偿经验,在南水北调中线水源区建立多元化的生态补偿机制.     

南水北调中线输水渠道中分水口的影响

为研究南水北调中线输水渠道中分水口流量变化对干渠的影响特征,选取天津分水口为例,采用一维Saint-Venant数学模型模拟计算该分水口各种分水状态下干渠中的水流过渡过程。采用虚拟渠道等效糙率法来模拟渠道中各类型的输水建筑物的影响。得出该分水口关闭时间超过33.6 h会导致紧邻下游端的西黑山节制闸前水位出现漫顶,分水口前水位下降速度与分水口流量变率呈线性变化关系,并给出了其拟合公式。     

南水北调中线工程对环境影响的评价

南水北调中线工程是一项大型水利工程，实施后对周围环境有很大影响，因而在前期研究中，必需搞好环境的分析与预测，其中主要有：调水对供水区环境的影响评价、水文情势变化对汉江中下游环境的影响、以及淹没和移民等问题对丹江口库区环境的影响评价等。     

输水管道穿南水北调总干渠方案研究

根据南水北调总干渠总体设计技术规定:输水管道穿越总干渠,其穿越建筑物不占用总干渠水头.为满足总体设计要求,根据输水管道管底高程、总干渠渠底高程及设计水位的相互关系,考虑了渠上管道桥和渠底倒虹吸两种穿越方案,通过技术、经济、施工等综合分析比较,确定输水管道穿总干渠建筑物型式为渠底倒虹吸,倒虹吸管外加防护箱涵.     

南水北调中线工程与汉江流域生态环境保护

1流域生态环境保护的必要性汉江是万里长江最长的支流,多年平均年径流量大于黄河,其上游是我国南水北调中线工程的水源地区,数年后贮存于丹江口水库的汉江水将流入河南、河北、北京、天津等华北水资源缺乏地区的城市与农村,实现跨流域调水的宏伟蓝图.南水北调是实现我国北方广大区域可持续发展的基础工程[1],是涉及地域广、施工时间长、影响范围大的巨型水资源开发利用项目.我国领导人和专家学者明确指出,南水北调工程必须重视和解决好生态环境问题,以促进我国社会经济的可持续发展[2,3].我国是世界上淡水资源较缺乏的国家之一,受季风气候影…