LBA-ECO CD-02 Carbon and Oxygen Isotopes in Atmospheric CO2 in the Amazon: 1999-2004

This data set reports carbon and oxygen stable isotope ratios of atmospheric carbon dioxide (CO2) collected at several forest and pasture sites and in the free troposphere over Amazonia. There are three comma-delimited ASCII files with this data set.

Atmospheric CO2 concentrations and isotope signatures were measured at ten different forest and pasture canopy sites across the states of Amazonas, Para, and Rondonia within the Brazilian Amazon between March 1999 and March 2004. Both daytime and nighttime profile samples were collected.

Samples of CO2 in the troposphere were collected during aircraft flights over the Amazon/Tapajos Rivers, FLONA Tapajos, and pasture/agriculture areas during five days in May 2003 (wet season). Samples were analyzed for carbon and oxygen isotopes of atmospheric CO2. Flights ranged from low altitudes to above the diurnal tropospheric boundary layer.

Measurements of carbon and oxygen stable isotope ratios of atmospheric carbon dioxide (CO2) are a powerful indicator of large-scale CO2 exchange on land across multiple spatial scales. Stable carbon isotope composition of leaf tissue and CO2 released by respiration (delta r) can be used as an estimate of changes in ecosystem isotopic discrimination that occur in response to seasonal and interannual changes in environmental conditions, and land-use change (forest-pasture conversion). Understanding of carbon dioxide stable isotope composition can play a central role in influencing our understanding of the extent to which terrestrial ecosystems are carbon sinks.

本数据集报告了在亚马逊地区多个森林和牧场以及自由对流层中收集的大气二氧化碳（CO2）的碳和氧稳定同位素比率。数据集包含三个以逗号分隔的ASCII文件。在大亚马逊地区，即亚马孙州、帕拉州和罗纳尼亚州，于1999年3月至2004年3月期间，对十个不同的森林和牧场冠层站点的大气CO2浓度和同位素特征进行了测量。白天和夜晚的剖面样本均被收集。在2003年5月（雨季）的五天内，通过飞机在亚马逊/塔帕若斯河、FLONA塔帕若斯以及牧场/农业区域进行飞行，收集了对流层中的CO2样本。样本被分析以确定大气CO2的碳和氧同位素。飞行范围从低空到日际对流层边界层之上。大气二氧化碳（CO2）的碳和氧稳定同位素比率的测量是表征陆地多空间尺度上大规模CO2交换的强有力指标。叶片组织和呼吸释放的CO2（delta r）的稳定碳同位素组成可以用来估算生态系统同位素分馏的变化，这些变化是对环境条件季节性和年际变化以及土地利用变化（森林-牧场转换）的响应。对二氧化碳稳定同位素组成的理解在影响我们对陆地生态系统碳汇范围的理解方面可以发挥核心作用。