LBA-ECO ND-01 STREAMWATER AND WATERSHED CHARACTERISTICS, RONDONIA, BRAZIL: 1998-1999

This data set provides the results of (1) synoptic streamwater sampling and analyses from numerous sites across Rondonia and (2) corresponding watershed characteristics derived from remote sensing and historical/available data sources.

Sixty streams, in both forested and non-forested sites, were sampled once during the dry season in August of 1998 and 49 of the same streams were sampled again during the wet season in January-February of 1999. Analyses included sodium (Na), calcium (Ca), magnesium (Mg), potassium (K), silica (Si), chloride (Cl), sulfate, pH, and acid neutralizing capacity.

Watershed characteristics, including soil cation content, pH, watershed lithology, area, percent deforested, and urban watershed population density, were derived and calculated from digitized soil maps and available soil profile analyses, digitized topographic maps, land use mosaics from Landsat Thematic Mapper (TM) images, and Brazilian census data.

The objective of the study was to determine the relative influence of watershed soil exchangeable cation content, rock type, deforestation, and urban population density on stream concentrations of base cations, dissolved silicon, chloride and sulfate in both the dry and wet seasons in a humid tropical region undergoing regional land use transformation. There are three comma-delimited data files with this data set.

本数据集包含两类研究成果：(1) 巴西朗多尼亚州（Rondonia）多个点位的同步河流水样采集与分析结果，以及(2) 基于遥感与历史/现有数据源推导得到的对应流域特征。
本研究共选取60条河流（涵盖森林与非森林流域），于1998年8月的旱季完成单次采样；其中49条河流于1999年1-2月的雨季再次采样。本次分析的水质指标包括：钠（Na）、钙（Ca）、镁（Mg）、钾（K）、硅（Si）、氯化物（Cl）、硫酸盐、pH值以及酸中和容量。
流域特征参数（含土壤阳离子含量、pH值、流域岩性、流域面积、森林砍伐占比以及城镇流域人口密度），通过数字化土壤地图与可用土壤剖面分析数据、数字化地形图、来自Landsat专题制图仪（Thematic Mapper, TM）影像的土地利用镶嵌图，以及巴西人口普查数据推导计算得到。
本研究的目标为：在经历区域土地利用转型的湿润热带地区，明确流域土壤交换性阳离子含量、岩石类型、森林砍伐程度以及城镇人口密度，对旱季与雨季河流中碱阳离子、溶解态硅、氯化物与硫酸盐浓度的相对影响。本数据集包含3个逗号分隔格式的数据文件。