Changes in permafrost ecosystem under the influences of human engineering activities and its enlightenment to railway construction

~~disturbedhigh-coldmeadowarea,theoriginalvegetationisverydifficulttorestorealthoughitssurfacelandscapecanberestoredtoacertaindegree.Borrowpitsandpilinggroundshavegreatdestructiontothehigh-coldmeadow,thehigh-coldmeadowecosystemalmostcannotbere-storedbynaturalprocesses,therefore,greateffortsshouldbemadetoavoidsettingupborrowgroundinthehigh-coldmeadowregion.AcknowledgementsThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(GrantNos.90102001and30270255)andtheKeyProjectionofKnowl…     

长期径流预报的灰色双向差分模型

本文基于灰色预测原理和双向差分理论，提出长期径流预报的灰色双向差分模型，实例应用表明，该模型由于获取了较多的历史径流信息，不仅能得到较为准确的径流预报值的拟合结果，还可得到非常可靠的长期径流趋势预报结果。     

黑河流域额济纳绿洲区水资源合理利用分析

应用多目标规划方法分析研究了额济纳绿洲区水资源合理利用的模式，探讨了黑河流域中下游间不同的输水条件下，额济纳绿洲东，西两河区域的水土资源利用方案和生态环境建设规模。     

西南贫困山区扶贫保障的山地灾害风险防控

发展以最大程度消除灾害风险为前提的山地灾害风险防控扶贫模式,对全面实现西南山区精准扶贫战略目标意义重大。本文在分析山地灾害对精准扶贫的影响及面临的主要问题的基础上,提出构建山地灾害风险防控与扶贫保障体系的主要措施,包括统筹山地灾害风险管理与扶贫开发规划、科学开展山地灾害风险评估、采取多种手段加强山地灾害综合治理、构建山地灾害风险防控监测预警机制、全面推动贫困人口防灾减灾。     

灌区水资源优化利用的水盐区分法

本文提出把灌区优化利用水资源同当地水盐状态特征结合起来的水盐区分法,依据土壤水盐特征把灌区划分为不同的分区,各分区以独立的水资源用户,建立其以改善或充分利用水盐环境的水资源优化利用模型,采用LP方法,组形成灌区多目标的LP模型集,求解该模型集,可得到优化的配水方案,实现以土壤水盐为状态指导灌溉的节水途径。以景泰川一期灌区为应用实例,论证了该方法的应用过程和有效性。     

灰色双向差分模型及其在石羊河流域泉水流量模拟与预测中的应用

本文基于灰色GM(1,1)建模理论和灰区间预测思想,运用双向差分方法建立了石羊河流域泉水流量模拟及预测模型:(?)_(t+1)=568.851-565.141×e~(-5.15×10~(-3)t)。经验证,拟合均方根误差RMSE=7.93％,预报平均误差为17.7％,效果较好。     

Influence of land cover changes on the physical and chemical properties of alpine meadow soil

Taking the alpine cold meadow grassland in the southeastern part of the Qinghai-Tibetan Plateau as an example ,this researcdh deals with the characteristics of apline meadow soil property changes,including soil nutrients,soil physical properties and soil mositure content under differcent land coverage conditions.With the degradation of grassland vegetation and the decline of vegetation coverage ,soil compactness reduces ,gravel content increases and bulk density increases ,The originally dense root-system layer is gradually denuded,making the soil coarse and gravel .The change of the organic matter contents with the vegetation coverage change in the surface soil layer (0-20cm) has shown an obvious cubic polynomial curve process ,The organic matter contents increas rapidly when land coverage is above 60%,contrarily decreases on a large scale when land coverage is below 30%,Between 30%-60% of land coverage the organic matter contents remain stable,The total N and organic matter contents remain stable.The total N and organic matter contents in soil have shown quite similar change regularity ,Following this the mathematic equations are derived to describe such change processes ,Moisture content in soil changes sharply with the vegetation coverage change,Soil moisture content change with the vegetation coverage change,Soil moisture content change with the vegetation coverage change has shown a quadratic parabola process,Results have shown that organic matter conternt and the total N content of the apline meadow soil decrease by 14890 kg/hm^2 and 5505kg/hm^2 respectively as the vegetation coverage reduces from 90% to less than 30%,the heavey changes of soil physical and chemical proerties with grassland degradation have made the recovery of alpine meadow ecological system impossible,The protection of alpine meadow vegetation is of vital importance to the maintenance of the regional soil environment and the regional ecological system.     

干旱内陆河流域景观生态的空间格局分析——以黑河流中游地区为例

干旱内陆河流域景观的空间结构受水土资源开发利用程度制约．通过划分景观分区和选取景观空间格局指标,分析研究了黑河流域中游地区景观的空间格局特征及其与人类活动及自然环境的关系,结果表明：１．土地资源开发程度高的区域,景观多样性、均匀性和破碎度值较大,景观优势度和分离度值则较小;２．研究区中部及南部耕地已成为主要景观类型．土地开发利用程度高,但中部绿洲区退化景观已具相当规模,且随沿山洪积扇区土地开发程度的提高,中下游生态环境退化趋势将加剧．     

甘肃民勤灌区作物种植局势决策

本文依据实际调查资料，分析了民勤灌区水土资源利用及作物有种植状况，应用灰色局势决策理论，通过划分决策分区和建立决策目标，对民勤灌区农作物种植局势进行了决策，提出了在现状水资源条件下，本区不同分区应优先发展的作用种类。