大气氮沉降通量观测方法

Observation methods for atmospheric nitrogen deposition

工农业的发展引起含氮化合物排放量日益增多,导致大气向地面输入的沉降量相应增加。大气氮沉降是自然生态系统重要的氮素来源,沉降量的增加必然会对生态系统的生物地球化学循环产生干扰。针对大气氮沉降组成复杂、时空变异性大、观测的技术方法不统一、研究结果之间可比较性差等关键科学问题,本文从大气氮沉降来源和组成出发,综述了过去几十年来国内外大气氮素干湿沉降在观测方法和测试手段方面的重要进展,详细描述了传统雨量计收集法、降水降尘仪法、阴阳离子交换树脂法、降尘缸收集法和沉降速率法等干、湿沉降观测方法的原理,对比不同方法存在的优点与不足;简要对比了国内外大气干、湿沉降通量状况,提供了大气氮沉降区域分布格局方面的量化信息;初步阐明了大气氮沉降观测研究的理论基础和观测原理,为对比分析不同观测方法获得的观测结果提供定性参考,并为不同生态系统氮沉降研究选择合理的观测方法提供理论依据。

Atmospheric nitrogen deposition has increased dramatically in recent years, due to the increasing discharge of nitrogenous compounds from industry and agriculture. Nitrogen deposition is an important nitrogen source of natural ecosystem, and its increase would disturb the ecosystem biogeochemical cycle. Because of the compositional complexity and large spatiotemporal variability of atmospheric nitrogen deposition as well as the disunity of measurement methods, it is difficult to compare the results from different nitrogen deposition studies. Aiming at the sources and composition of atmospheric nitrogen deposition, this paper summarized the past decades research progress at home and abroad in the observation and test methods of atmospheric nitrogen deposition, described in detail the principles and operations of the methods for measuring wet-and dry nitrogen deposition （traditional rain collection, automatic collection by instrument, ion exchange resin column collection, dust cylinder wet collection, and deposition velocity method）, and compared the advantages and disadvantages of these methods. Meanwhile, based on the comparison of related studies at home and abroad, this paper also provided the regional quantitative information of nitrogen deposition flux. Presenting a brief review of representative techniques for nitrogen deposition observation, this paper preliminarily elucidated the theoretic bases and principles of atmospheric nitrogen deposition measurement, gave a qualitative reference for the contrastive analysis of different observation results, and provided theoretical bases for the reasonable choice of nitrogen deposition observation.