High-resolution, in situ measurement of dissolved CH4, d13CH4 and C2H6 at Lake Aiguebelette using a Membrane Inlet Laser Spectrometer

Here, a continuous high-resolution dissolved CH4, d13CH4 and C2H6 measurements made with an in situ Membrane Inlet Laser Spectrometer instrument at lake Aigubelette on surface water (50 cm water depth) are reported. The measurements were performed on May 15th 2019 on the shallow areas in the southwest of the lake from near the shore to the islands in the center of the lake, then into the channel of Thiers at the lake outlet. The coordinates were provided by a Garmin 18x GPS unit with an accuracy of 15m. In the attached file we reported the local time (in hh:mm:ss and as fract time), the coordinates, the distance from shore in meter, the water depth in meter, the concentration of dissolved CH4 in mol fraction and in mol per liter of water, the concentration of dissolved C2H6 in mol fraction and the d13CH4 in permil. The data on the channel of Thiers were reported in a separated file. The accuracies of the measurements are +/-12% for the concentration of CH4 and C2H6 (limit of detection 0.06 ppm or 0.1 nmol L-1 for CH4, and 2 ppb 4 pmol L-1 for C2H6) and +/-2.2 permil for the d13CH4 . All uncertainties are expressed with a 2-sigma confidential interval. In the original files dissolved C2H6 concentrations were wrong, and have been corrected in the version V2.本数据集报道了使用原位膜进样激光光谱仪（Membrane Inlet Laser Spectrometer），于2019年5月15日在艾古布莱特湖（Lake Aigubelette）50厘米水深的表层水体中获取的连续高分辨率实测数据，涵盖溶解甲烷（CH4）、δ¹³CH4及乙烷（C2H6）的浓度信息。本次采样沿湖西南浅水区开展，采样路线从近岸延伸至湖中心岛屿，随后进入湖泊出水口蒂耶尔（Thiers）航道。采样坐标由佳明（Garmin）18x型GPS设备采集，定位精度为15米。 随附文件中包含了采样当地时间（格式为hh:mm:ss及小数时间形式）、采样坐标、离岸距离（单位：米）、水深（单位：米）、以摩尔分数及每升水体中物质的量浓度表示的溶解甲烷浓度、以摩尔分数表示的溶解乙烷浓度，以及δ¹³CH4（单位：‰）。蒂耶尔航道的实测数据单独收录于另一份文件中。 本次测量的不确定度如下：甲烷与乙烷浓度的相对误差为±12%（甲烷的检出限为0.06 ppm或0.1 nmol·L⁻¹，乙烷的检出限为2 ppb或4 pmol·L⁻¹）；δ¹³CH4的测量偏差为±2.2‰。所有不确定度均以2σ置信区间形式表示。 原始文件中溶解乙烷浓度存在数据错误，现已在V2版本中完成修正。