【作者】 段雷；

【导师】 郝吉明；

【作者基本信息】 清华大学 ， 环境工程， 2000， 博士

【摘要】 为了满足中国酸沉降控制的需要,本研究在对土壤风化速率和生物吸收速率等重要参数进行系统研究的基础上,用稳态法完成了中国酸沉降（包括硫沉降和氮沉降）临界负荷区划:利用实验测定和理论计算相结合的方法首先确定了中国主要土壤类型的风化速率,结果表明中国南方富铝土区域以及东北的硅铝土区域的风化速率普遍较低(通常低于1.0keq·ha^-1·a^-1),而西北地区干旱土和高山土的风化速率则较高;基于植被的生产力和优势植物的化学成分确定了中国植被对氮和盐基阳离子的吸收速率;在地理信息系统（GIS）支持下得到0.1°×0.1°（经纬度）和1°×1°两种不同分辨率下的中国酸度临界负荷图、硫沉降临界负荷图和氮沉降临界负荷图。从酸度临界负荷图上看,中国临界负荷最小(<0.2keq·ha^-1·a^-1)的地区主要分布在东北的大兴安岭北端和三江平原,其次是东北小兴安岭和长白山,青藏高原南部雅鲁藏布江河谷,云南西南部怒江和澜沧江流域,以及雷州半岛和海南岛西部,而我国酸沉降污染较为严重的富铝土区域,总体上都能够承受0.5～2.0keq·ha^-1·a^-1的酸沉降。于是,根据酸度临界负荷可以将中国大致划分为东南和西北两部分,东南部大部分地区只能接受小于2.0keq·ha^-1·a^-1的酸沉降,而西北部普遍可以接受大于2.0keq·ha^-1·a^-1的酸沉降,其分界线基本上与400mm等降水量线重合。与酸度临界负荷的分布相似,中国硫沉降临界负荷在总体上也呈现东高西低的趋势,而中国氮沉降临界负荷的分布则正相反,呈现自西向东逐渐增加的格局。中国氮沉降临界负荷最低(<1.0g·m^-2·a^-1)的地区分布青藏高原西部和阿拉善高原,而氮沉降临界负荷最高(>4.0g·m^-2·a^-1)的地区则包括东北平原、华北平原、长江中下游平原以及四川盆地等。在各种生态系统中,针叶林、草原和荒漠对氮沉降比较敏感,而阔叶林、灌丛和草甸则对氮沉降较不敏感。综合考虑硫沉降临界负荷和氮沉降临界负荷可以将中国划分为七个分区,每个区内硫沉降或氮沉降的控制重点是不同的。更多还原

【Abstract】 To meet the requirement of acid deposition control in China, critical loads of acid deposition （include sulfur and nitrogen） were mapped through the steady state mass balance （SSMB） method. The weathering rates of Chinese soils necessary for applying SSMB were derived based on the experimental measurement and theoretical calculation. Result shows that the weathering rates were very low (usually lower than 1.0 keq·ha^-1·a^-1) for allite in south China and silalsol in northeast China, but very high for xerosol and alpine soil in northwest China. The growth uptakes of nitrogen and base cations, another two important parameters, were also derived by multiplying the annual increases in biomass by the element contents of the vegetation. Supported by a geographical information system （GIS）, critical load maps of acidity, sulfur and nitrogen of China were compiled with resolutions both of 0.1° （latitude） × 0.1° （longitude） and 1° × 1°. As can be seen from the critical load map of acidity, the lowest critical loads (< 0.2 keq·ha^-1·a^-1) occurred on the Daxingan Mountain and the Sanjiang Plain in northeast China, then followed by the Xiaoxingan Mountain and the Changbai Mountain in northeast China, the valley of the Yaluzangbu River on the south of the Tibetan Plateau, the catchments of the Nu River and the Lancang River in the southwest of Yunan province, Leizhou Peninsula, and the west of Hainan Island. The critical loads of Ferralsol areas in south China, where acid deposition is very high, were intermediate and in the range of 0.5².0 keq·ha^-1·a^-1. Therefore, according to the critical loads of acidity, China might be divide into two parts approximately by the 400mm isohyet - the northwest part could generally tolerate more than 2.0 keq·ha^-1·a^-1 acid deposition, but the southeast one could not. Similar to the distribution of the critical loads of acidity, the critical loads of sulfur were high in west China and low in east China. However, the critical loads of nitrogen were low in the west and high in the east. The lowest critical loads of nitrogen (<1.0 g·m^-2·a^-1) occurred on the west of the Tibetan Plateau and on the Alashan Plateau, and the highest (> 4.0 g·m^-2·a^-1) on the Dongbei Plain, the Huabei Plain, the Changjiangzhongxiayou Plain, and the Sichuan Basin, etc. Among all ecosystems, coniferous forests, steppes and deserts were more sensitive to nitrogen deposition than broad-leaf forests, shrubs and meadows. Based on the critical loads of both sulfur and nitrogen, China might be divided into seven regions. The priority of sulfur or nitrogen to be controlled is different in these regions.更多还原