Cleveland Bay Automated Marine Weather And Oceanographic Station

This dataset contains meteorological and sea temperature data from two automatic weather stations moored at different times and locations within Cleveland Bay (Townsville).The first weather station was deployed on Channel Marker #10 (19° 11.95S, 146° 51.89 E). Data from this weather station covers the period 3rd July 1990 to 21st October 1992. This weather station was then removed and redeployed on Cape Cleveland.The current weather station is located on channel marker #S5, approximately 1 kilometre from Bremner Point on Magnetic Island (19° 09.35S, 146°52.87E). Data collection from this station commenced on the 7th December, 1999.These data are collected to support scientific research at AIMS. Data are made available on request to other researchers and to the public.The current weather station is a Campbell Scientific Australia System.Data recorded: Sea Temperature (1.9m and 8.5m at MSL), Barometric Pressure, Air Temperature, Solar Radiation (PAR), Wind Direction True (scalar averaged), Wind Speed True (10 min average prior to every half hour and maximum wind gust).1. Operation and Weather SensorsThe weather stations collect and store data in electronic memory every half-hour. A central base station calls each remote station regularly using HF radio or telephone lines. The data is transmitted over the radio as a frequency shift keyed signal, organised as packets of information. Errors are detected using parity and check sum methods. Invalid packets are identified by the Base Station, which requests they be sent again. This concept allows recovery of a very high percentage of the data despite poor communications. Remote stations store data for 21 days. Features such as automatic operation, remote control, remote time setting, built in diagnostics, have been developed and incorporated.The sensors are a key part of a weather station. The following are chosen considering the cost, reliability and accuracy.* R.M.Young manufactures the wind sensor, a model number 05103. It is a propeller type with the advantages of being highly linear, highly interchangeable and having a low threshold. Wind direction is measured as the direction the wind is coming from.* The solar radiation sensor is an Under Water Quantum Sensor made by Licor. It measures light in terms of its "Photosynthetically Active Radiation" (PAR). The spectral response is defined and weighted. Drift due to aging of the filters has proven to be a problem, but this applies to similar units too.* Temperature sensors are all Omega Interchangeable Thermistors. These are interchangeable and have high accuracy, but reliability has proven a problem. We are considering alternatives.* The barometric sensor was a modified Aanderaa type on earlier stations. The Mk2 stations were fitted with a Weathertronics Unit. Now all stations are Mk3 stations fitted with a Vaisala barometer which is more interchangeable and more accurate.2. System AccuracySystem accuracy is calculated as the sum of errors caused by:* Calibration* Interchanging sensors* Drift with time* Effects of an ambient temperature range from 0-40 degrees C.The following are the specifications of the sensors used with Mk3 stations. A new sensor suite will be used with Mk5 stations, partly based on the Vaisala WXT510 weather sensor.Both the temperature and wind sensors are interchangeable, and not individually calibrated, though some individual sensors have been checked against standards.* Air Temperature: Interchangeable thermistor and electronics is within +/- 0.4 deg. C, with a 30 seconds settling time in air. There are additional errors due to the aspiration of the temperature screen at low wind speeds.* Water temperature: Interchangeable thermistor and electronics is within +/- 0.4 deg. C, with a 30 minutes settling time in water. A higher precision in situ calibration is normally used (around +/- 0.1 degrees), traceable to a 0.04 degrees standard.* Solar radiation (PAR): +/- 5% of reading. Sensor drift is approximately -4% per year initially.* Barometric pressure: +/- 1 hecto Pascal.* Wind speed: 2% of reading +/- 0.1% FSD.* Wind direction: 2% of reading +/- 0.1% FSD.Electrical settling time for solar radiation and wind parameters is 7 seconds. This is necessary for anti-aliasing filters. Mk1 and Mk2 stations averaged 16 samples over the 16 seconds before logging. Mk3 stations use a continuously averaging software system. The wind readings are vector averaged, so direction is accounted for properly.Calibration procedures and routines are detailed on the Engineering website.3. Wind Sensor SpecificationThe following are additional specifications of the wind sensors used with Mk3 stations. A new sensor will be used with Mk5 stations. Wind sensors are mounted at a nominal 10 meters above water.The R.M. Young sensor has the following characteristics:* Wind SpeedRange: 0-60 m/sPitch: 29.4 cm air passes per rev.Distance constant: 2.7 m for 63% recovery* Wind DirectionRange: 360 deg, with 5 deg electrically open at northDamping ratio: 0.25Delay distance: 1.5 m for 50% recoveryThreshold: 1.0 m/s @ 10 deg.Displacement: 1.5 m/s @ 5 deg. displacementDamped w/length: 7.4 mUndamped w/length: 7.2 m4. Underwater Temperature SensorsThese sensors are interchangeable thermistors in Mk3 stations. They can be mounted a significant distance from the weather station, using a 2 wire connection. The basic accuracy is due to the use of interchangeable units. However improved accuracy is obtained by calibrating against a precision reference sensor in situ. These are in turn calibrated against a standard traceable to 0.04 degrees.

本数据集包含来自两个自动气象站的气象与海水温度数据，这两个气象站于不同时段部署在克利夫兰湾（汤斯维尔，Townsville）内的不同位置。首个气象站部署于10号航道浮标（19°11.95'S，146°51.89'E），其数据覆盖时段为1990年7月3日至1992年10月21日。此后该气象站被移除并重新部署至克利夫兰角。当前的气象站位于S5号航道浮标，距离磁岛（Magnetic Island）上的布雷姆纳角约1公里，坐标为19°09.35'S，146°52.87'E，该站自1999年12月7日起启动数据采集工作。

本数据集的采集数据用于支持澳大利亚海洋科学研究所（Australian Institute of Marine Science, AIMS）的科研工作，可应其他研究者及公众的请求对外提供共享。当前的气象站为澳大利亚坎贝尔科学（Campbell Scientific Australia）系统。

本次记录的参数包括：海水温度（平均海平面Mean Sea Level, MSL处的1.9m与8.5m深度）、气压、气温、太阳辐射（光合有效辐射Photosynthetically Active Radiation, PAR）、真风向（标量平均）、真风速（每半小时前进行10分钟平均并记录最大阵风）。

1. 运行与气象传感器
气象站每半小时采集并存储数据至电子存储器。中央基站通过高频无线电（High Frequency, HF）或电话线定期呼叫每个远程站，数据以频移键控（frequency shift keyed）信号形式通过无线电传输，组织为信息数据包。基站使用奇偶校验（parity）与校验和（check sum）方法检测错误，识别无效数据包后请求重传，即便通信条件不佳，该机制也可恢复绝大多数有效数据。远程站可存储21天的数据，系统集成了自动运行、远程控制、远程时间设置、内置诊断等功能模块。

传感器是气象站的核心组成部分，选型综合考量了成本、可靠性与精度：
* 风速风向传感器由R.M.Young制造，型号为05103，属于螺旋桨式传感器，具备高线性度、高互换性与低启动阈值的优势，风向测量以风的来向为基准。
* 太阳辐射传感器为Licor公司生产的水下量子传感器，以光合有效辐射（PAR）为单位测量光照，其光谱响应经过定义与加权。过滤器老化导致的漂移是已知问题，但同类传感器均存在该缺陷。
* 温度传感器均为欧米茄（Omega）公司的互换式热敏电阻，具备互换性与高精度，但可靠性存在不足，目前团队正在考虑替代方案。
* 早期气象站使用的是改装过的Aanderaa型气压传感器，Mark2（Mk2）型站配备Weathertronics单元，当前所有站点均为Mark3（Mk3）型站，搭载互换性与精度更优的维萨拉（Vaisala）气压传感器。

2. 系统精度
系统精度由以下误差项之和计算得出：校准误差、传感器互换误差、随时间产生的漂移误差、0~40℃环境温度范围带来的影响。

以下为Mark3型站所用传感器的技术规格。Mark5（Mk5）型站将采用全新的传感器套件，部分基于维萨拉WXT510气象传感器。

尽管部分传感器已对照标准进行过校准，但温度与风速传感器均为互换式设计，未进行单独校准。
* 气温：互换式热敏电阻与电子系统的误差范围为±0.4℃，在空气中的稳定时间为30秒，低风速下的温度屏通风会带来额外误差。
* 水温：互换式热敏电阻与电子系统的误差范围为±0.4℃，在水中的稳定时间为30分钟，通常会采用原位高精度校准（误差约±0.1℃），该校准可溯源至0.04℃的标准。
* 太阳辐射（PAR）：误差为读数的±5%，传感器初始年漂移约为-4%。
* 气压：±1百帕。
* 风速：读数的±2% ±0.1%满量程偏差（full scale deflection, FSD）。
* 风向：读数的±2% ±0.1%满量程偏差（FSD）。

太阳辐射与风速参数的电稳定时间为7秒，这是抗混叠滤波器（anti-aliasing filters）的设计要求。Mark1（Mk1）与Mark2型站在记录前的16秒内对16个采样点取平均，Mark3型站则采用持续平均的软件系统。风速读数为矢量平均，因此可正确反映风向信息。

校准流程与规程详见工程网站。

3. 风速传感器规格
以下为Mark3型站所用风速传感器的补充规格。Mark5型站将采用全新的传感器。风速传感器的标称安装高度为距水面10米。

R.M.Young传感器的特性如下：
* 风速：量程0~60m/s，每转气流通过距离为29.4cm，63%响应恢复距离常数为2.7m。
* 风向：量程360°，正北方向电气开路偏差为5°，阻尼比为0.25，50%响应恢复延迟距离为1.5m，启动阈值为1.0m/s（10°风速下），位移响应为1.5m/s（5°位移下），带阻尼的特征长度为7.4m，无阻尼的特征长度为7.2m。

4. 水下温度传感器
Mark3型站所用的水下温度传感器为互换式热敏电阻，可通过两线制连接方式安装在距离气象站较远的位置。其基本精度来自于互换式设计，但通过原位对照高精度参考传感器进行校准可获得更高精度，而该参考传感器本身可溯源至0.04℃的标准。