North Temperate Lakes LTER: High Frequency Meteorological and Dissolved Oxygen Data - Sparkling Lake Raft 1989 - current

The instrumented raft on Sparkling Lake is equipped with a dissolved oxygen and CO2 sensors, a thermistor chain, and meteorological sensors that provide fundamental information on lake thermal structure, weather conditions, evaporation rates, and lake metabolism. Estimating the flux of solutes to and from lakes requires accurate water budgets. Evaporation rates are a critical component of the water budget of lakes. Data from the instrumented raft on Sparkling Lake includes micrometeorological parameters from which evaporation can be calculated. Raft measurements of relative humidity and air temperature (2 m height), wind velocity ( at 1, 2, and 3 m heights; but beginning in 2008, only at 2 m) ,and water temperatures (from thermistors placed throughout the water column at intervals varying from 0.5 to 3m) are combined with measurements of total long-wave and short-wave radiation data from a nearby shore station to determine evaporation by the energy budget technique. Comparable evaporation estimates from mass transfer techniques are calibrated against energy budget estimates to produce a lake-specific mass transfer coefficient for use in estimating evaporation rates. After correcting for flux to or from the atmosphere and vertical mixing within the water column, high frequency measurements of dissolved gases such as carbon dioxide and oxygen can be used to estimate gross primary productivity, respiration, and net ecosystem productivity, the basic components of whole lake metabolism. Other parameters measured include precipitation, wind direction (beginning in 2008), and barometric pressure (beginning in 2008). Sampling Frequency: one minute; averaged to hourly and daily values as well as higher resolution values such as 2 min and 10 min. Number of sites: 1

闪光湖（Sparkling Lake）上的搭载式观测筏配备了溶解氧（dissolved oxygen）与二氧化碳（CO₂）传感器、热敏电阻链（thermistor chain），以及气象传感器（meteorological sensors），可获取湖泊热结构、气象条件、蒸发速率及湖泊代谢相关的基础数据。估算湖泊内外溶质通量需依托精准的水量平衡计算，而蒸发速率是湖泊水量平衡的核心组成部分。闪光湖观测筏采集的数据包含微气象参数，可用于蒸发速率的计算。观测筏同步采集了相对湿度与2米高度处的气温、不同高度（原1、2、3米，2008年起仅保留2米高度）的风速，以及沿水柱以0.5至3米不等间隔布设的热敏电阻所测得的水温；上述数据结合附近岸基站点采集的总长波与短波辐射数据，可通过能量平衡法（energy budget technique）计算蒸发速率。针对传质法（mass transfer techniques）得到的蒸发速率估算结果，以能量平衡法的估算结果进行校准，可得到适配该湖泊的传质系数，用于后续蒸发速率的估算。在修正了大气与湖泊间的气体通量以及水柱内的垂直混合效应后，高频采集的二氧化碳、氧气等溶解气体数据可用于估算总初级生产力（gross primary productivity）、呼吸作用（respiration）与净生态系统生产力（net ecosystem productivity）——这些是全湖代谢的核心组成部分。此外，本次观测还采集了降水、（2008年起新增的）风向与气压数据。采样频率为1分钟，数据可整合为小时、日尺度均值，同时也可生成2分钟、10分钟等更高分辨率的数据集。观测点位数量：1个