Precipitation and dry deposition chemistry concentrations and fluxes, Andrews Experimental Forest, 1969 to present

Collection and analyses of precipitation chemistry were initiated in 1969 at the low-elevation Primary Met site, and in 1973 at a mid-elevation Hi-15 site. Rain collection samples accumulate from one week to three weeks in bulk and NADP type collectors and then are transported to Cooperative Chemical Analytical Laboratory (CCAL) for analysis. Analytes include nitrogen, phosphorus, carbon, and cations and anions as well as pH, conductivity, alkalinity and particulate sediment. Concentration and volume of precipitation are combined for inflow. Dry deposition chemistry concentrations began in 1989 and are analyzed 2-4 times per year at one site. The original objectives were to evaluate precipitation chemistry inputs versus chemistry outputs in streamflow from forested watersheds. The study has evolved into a general monitoring effort for precipitation chemistry that is among the least contaminated of any within the USA. This study is conducted in conjunction with Andrews streamflow chemistry (CF002) and the U.S. National Atmospheric Deposition Program (NADP).

降水化学采样与分析工作于1969年在低海拔一级气象站点（Primary Met site）启动，并于1973年延伸至中海拔Hi-15站点。雨水采集样品通过积集式与NADP型采样器开展1至3周的累积采样，随后被运送至合作化学分析实验室（Cooperative Chemical Analytical Laboratory, CCAL）进行分析。本次分析的分析物涵盖氮、磷、碳、阴阳离子，以及pH值、电导率、碱度与颗粒物沉积物。研究人员将降水浓度与降水量进行联合处理，以核算流域入流相关参数。干沉降化学浓度监测工作始于1989年，目前在单个站点每年开展2至4次分析检测。本研究的初始目标为评估森林流域溪流中降水化学输入与径流化学输出的差异。如今该研究已发展为一项综合性降水化学监测工作，其监测区域是全美受污染程度最低的区域之一。本研究与安德鲁斯溪流化学（CF002）项目及美国国家大气沉降项目（NADP）联合开展。