North Temperate Lakes LTER: High Frequency Data: Meteorological, Dissolved Oxygen, Chlorophyll, Phycocyanin - Lake Mendota Buoy 2006 - current

The instrumented buoy on Lake Mendota is equipped with limnological and meteorological sensors that provide fundamental information on lake thermal structure, weather conditions, and lake metabolism. Data are collected every minute. Hourly and daily averages are derived from the high resolution (1 minute) data. Hourly and daily values may not be current with high resolution data as they are calculated at the end of the season. Meteorological sensors measure wind speed, wind direction, relative humidity, air temperature, and photosynthetically active radiation (PAR). Not all sensors are deployed each season. A list of sensors used since the first deployment in 2006 is provided as a downloadable CSV file. The buoy is removed during the winter when the lake is ice-covered (typically Dec-Apr). Lake temperature data collected at the same buoy site can be found in an ancillary dataset. Number of sites: 1. Location lat/long: 43.0995, -89.4045 Notable events: 2017 - A boating mishap caused the loss of air temperature, relative humidity, and wind sensors between May 28 and July 11. The dissolved oxygen sensor had significant biofouling from algae and zebra mussels. 2019 - A YSI EXO2 sonde was added to the buoy and includes DO, chlorophyll, phycocyanin, specific conductance, pH, fDOM, and turbidity sensors. The chlorophyll and phycocyanin sensors replace Turner Cyclops 7 fluorometers that had been in use in prior years. Both sets of sensors output RFU, but have significant magnitude differences. The YSI pH, DO, and specific conductance sensors were cleaned and recalibrated every two weeks. 2020 - Cleaning and calibration of the YSI sensors occurred nearly every week. The dissolved CO2 sensor was not operating between July 2 and September 17. 2021 - Due to power and communications issues, the buoy was not operating August 22-31, and data is intermittent between November 8 and December 3. An effective method to keep the underwater PAR sensor mostly free of biofouling algae has been employed. 2022 - Buoy was not operating June 6-9 and July 2-5 due to power issues. Underwater PAR sensor unusable after October 1. 2023 - Conductivity sensor was not operational Apr 27 - May 24. The sensor was replaced. The wiper for the YSI sonde had failed Nov 4 - 14, which significantly affected four sensors: chlorophyll, phycocyanin, conductivity, and turbidity. 2024 - CO2 sensor failed on May 22 and was not used for the rest of the season. The buoy communications were down June 13-19, so no data exists for those dates. The PAR sensor was broken from August 30 - Sept 4.蒙纳托湖（Lake Mendota）上的配备仪器浮标搭载了湖沼学与气象学传感器，可提供湖泊热结构、天气状况及湖泊代谢的基础信息。数据采集频次为每分钟1次，基于该高分辨率（1分钟）数据可生成小时均值与日均值。由于小时值与日均值在当季结束后统一计算，因此可能无法与实时高分辨率数据同步更新。 气象传感器可测量风速、风向、相对湿度、气温以及光合有效辐射（Photosynthetically Active Radiation, PAR）。并非所有传感器都会在每个观测季悉数部署。自2006年首次部署以来所使用过的传感器清单，可通过可下载的CSV文件获取。 当湖面封冻（通常为12月至次年4月）时，浮标将被回收。同一浮标站点采集的湖水温度数据可于附属数据集内获取。 站点数量：1个。位置坐标（纬度/经度）：43.0995, -89.4045 显著事件： 2017年：一起船舶作业事故致使5月28日至7月11日期间的气温、相对湿度及风速传感器遗失。溶解氧传感器因藻类及斑马贻贝附着产生严重生物污损。 2019年：浮标新增YSI EXO2型多参数水质探头，搭载溶解氧（DO）、叶绿素、藻青蛋白、比电导、pH、有色溶解有机物（fDOM）及浊度传感器。原有特纳Cyclops 7型荧光计被叶绿素与藻青蛋白传感器取代。两类传感器均输出相对荧光单位（Relative Fluorescence Unit, RFU），但数值幅度存在显著差异。YSI的pH、溶解氧及比电导传感器每两周进行一次清洁与重新校准。 2020年：YSI传感器的清洁与校准工作几乎每周开展一次。溶解二氧化碳传感器于7月2日至9月17日期间处于停运状态。 2021年：受电力与通信故障影响，浮标于8月22日至31日期间停运，11月8日至12月3日期间数据存在间断。现已采用有效方法保障水下PAR传感器基本免受藻类生物污损。 2022年：受电力问题影响，浮标于6月6日至9日及7月2日至5日期间停运。水下PAR传感器于10月1日后无法正常工作。 2023年：电导传感器于4月27日至5月24日期间无法正常运行，后已完成更换。YSI多参数探头的刮片装置于11月4日至14日发生故障，对叶绿素、藻青蛋白、电导及浊度共4项传感器的观测结果造成显著影响。 2024年：CO₂传感器于5月22日发生故障，当季剩余时段均未投入使用。浮标通信系统于6月13日至19日中断，该时段无有效观测数据。PAR传感器于8月30日至9月4日期间损坏。