Methane ebullition flux data from thermokarst lakes, 2003-2010

We collected ebullition data from thermokarst lakes near the Northeast Science Station in Cherskii, Russia (68.75°N, 161.39°E ) and Fairbanks, Alaska (64.92°N, 147.85°W) during the years 2003-2010. Ebullition data were collected using submerged bubble traps placed over discrete ebullition seeps. Ebullition values are reported volumetrically (ml gas per seep per day) and on a methane mass basis (mg CH4 per seep per day), the latter based on mean values of methane measured in ebullition seeps on the study lakes [A = 82±7 % CH4; B = 83±12 % CH4; C = 85±5 % CH4; HS = 89±3 % CH4]. Methods of ebullition flux measurements and seep classification (A, B, C or Hotspot (HS) type) are described in detail by Walter Anthony et al. 2010, Limnology and Oceanography Methods.
Note 1: The Alaska data shows lots of zeros on C type seeps because semi-automated flux traps allowed high temporal resolution data collection. In Siberia, volumetric flux measurements made with manual traps were sometimes interpolated over periods of multiple days.
Note 2: The non-interpolated columns show data resulting from tipping events on the wet-tip bubble traps. On days where there was only one tip event, the rate of gas accumulation in the tipping cup is unknown. The interpolated column averages the gas volume in the one-tip event over the number of days since the previous tipping event, which is the period over which gas in the one-tip event may have accumulated.
Walter Anthony, K.M., D. Vas, L. Brosius, F.S. Chapin III, S.A. Zimov, Q. Zhuang, 2010. Estimating methane emissions from northern lakes using ice bubble surveys. Limnology and Oceanography Methods 8, 592-609.

本数据集采集了俄罗斯切尔斯基市东北科学站附近（北纬68.75°，东经161.39°）与美国阿拉斯加州费尔班克斯市附近（北纬64.92°，西经147.85°）的热融喀斯特湖（thermokarst lakes）在2003年至2010年间的冒泡排放（ebullition）数据。冒泡排放数据通过部署在离散冒泡渗漏点上方的水下气泡收集阱（submerged bubble traps）采集。冒泡排放数值以体积单位（每渗漏点每日毫升气体）与甲烷质量单位（每渗漏点每日毫克甲烷，CH4）两种形式报告，后者基于研究湖泊冒泡渗漏点中测得的甲烷平均占比计算[A = 82±7 % CH4；B = 83±12 % CH4；C = 85±5 % CH4；HS = 89±3 % CH4]。冒泡排放通量的测量方法及渗漏点分类标准（分为A、B、C类或热点（Hotspot, HS）类）已由沃尔特·安东尼（Walter Anthony）等人2010年发表于《湖沼学与海洋学方法（Limnology and Oceanography Methods）》的研究详细阐述。

注释1：阿拉斯加数据集的C类渗漏点存在大量零值数据，原因在于半自动通量阱可实现高时间分辨率的数据采集；而在西伯利亚地区，采用手动阱开展的体积通量测量结果有时会按多日周期进行插值处理。

注释2：非插值列展示了湿尖型气泡收集阱（wet-tip bubble traps）发生倾倒事件时得到的数据。若单日仅发生一次倾倒事件，则倾倒收集杯内的气体累积速率未知。插值列将单次倾倒事件中的气体体积，按自上次倾倒事件以来的天数（即单次倾倒事件中气体可能的累积周期）进行平均处理。

参考文献：
K.M. 沃尔特·安东尼（K.M. Walter Anthony）、D. 瓦斯（D. Vas）、L. 布罗西乌斯（L. Brosius）、F.S. 查宾三世（F.S. Chapin III）、S.A. 季莫夫（S.A. Zimov）、Q. 庄（Q. Zhuang），2010年。利用冰下气泡调查估算北方湖泊甲烷排放量。《湖沼学与海洋学方法（Limnology and Oceanography Methods）》8卷，第592-609页。