UV climate over the Southern Ocean south of Australia, and its biological impact - 1994 data

Ozone depletion over Antarctica increases UVB irradiances reaching the Earth's surface in the region. Marine microbes, that support the Antarctic food web and play an integral part in carbon cycling, are damaged by UVB. This research determines Antarctic UV climate, biological responses to UV from the molecular to community level, and combines these elements to predict UV-induced changes in Antarctic marine microbiology.A season of field work was undertaken over November and December 1994 based from Davis Station with the intention of making field measurements of ultraviolet radiation in the fast ice environment, as well as some of the lakes in the Vestfold Hills.InstrumentationThe instrument for the measurements was a Macam spectral radiometer, owned by Geography and Environmental Studies, University of Tasmania. Field personnel were Dr Kelvin Michael (IASOS) and Mr Michael Wall (Honours student, Geography and Environmental Studies, UTas).The radiometer was equipped with a 25-metre quartz light pipe, with a cosine sensor attachment at the end. To make a measurement of ultraviolet irradiance, the sensor would be oriented so that its sensing surface was horizontal, and it would collect light which was then transmitted along the light pipe to the radiometer - a suitcase-sized unit which ran on battery power in the field. The radiometer was encased in a wooden box lined with polystyrene foam to provide protection from the elements and heat insulation. The radiometer was controlled via a laptop PC and the data were stored on the hard disk of the PC.MeasurementsMeasurements of the attenuation of ultraviolet and visible radiation as a function of wavelength in water were made at the ice edge and lake measurement sites. At the ice edge, the light pipe was spooled over a wheel and lowered to preset depths (typically 1,2,4,8,16 and 32 m below the water surface). On a lake, a 25-cm augur hole was drilled, and the light pipe was lowered by hand to various depths, the exact depths chosen depended on the depth of the lake. Where the lake ice conditions permitted, a frame was lowered through the hole and used to lever the light pipe against the underside of the ice and a measurement of the ultraviolet and visible transmission of the sea ice was collected. In all cases, measurements of the ultraviolet and visible surface irradiance were collected before and/or after the sub-surface measurements. When the sky conditions were sufficiently clear, the direct and diffuse components of the ultraviolet and visible irradiance values were estimated, via the use of a shading apparatus. This would ensure that the radiometer would measure the diffuse component of the radiation field, allowing the direct component to be estimated by subtraction of the diffuse from the global (unshaded) measurement. On some occasions, the upwelling irradiance from the snow or ice surface was also measured, providing information on the spectral albedo of the surface.At each measurement, spectral irradiance values were generally collected for two spectral ranges: UV-B (280 - 400 nm, in 1-nm steps) and visible (400 - 700 nm, in 5-nm steps). In some cases, the wavelength boundaries were different - eg 280 - 350 nm for the UV-B, or 550 - 680 nm in the visible (corresponding to channel 1 of the NOAA AVHRR sensor). The data were stored by the PC as raw data files. The names of these files are automatically defined from the time on the logging PC as 'hhmmss.dti'. Note that the PC was operating on Australian Eastern Summer Time, 4 hours ahead of DLT. These data files were later read into Excel spreadsheets for manipulation.See the linked report for further information.The measurements are all in units of watts per metre squared per nanometre (Wm^-2 nm_-1)The heading UV-B refers to the fact that the data are collected in the ultraviolet part of the spectrum (280 - 400 nm)The heading AVHRR refers to the fact that the data are collected in the visible part of the spectrum (400 - 700 nm)The fields in this dataset are:UV RadiationWavelengthDepthAVHRR

南极上空的臭氧损耗会增加抵达该区域地球表面的UVB（中波紫外线）辐照度。支撑南极食物网并在碳循环中发挥不可或缺作用的海洋微生物会受到UVB的损伤。本研究旨在探明南极紫外辐射气候特征、从分子到群落层面的生物对紫外辐射的响应，并整合这些要素以预测UVB诱导的南极海洋微生物学变化。

1994年11月至12月，研究团队于戴维斯站（Davis Station）开展了一季野外作业，旨在对海冰环境以及韦斯特福尔丘陵（Vestfold Hills）内的部分湖泊开展紫外辐射实地测量。

### 仪器设备
本次测量使用的设备为塔斯马尼亚大学地理与环境研究学院所属的Macam光谱辐射计。野外作业人员为Kelvin Michael博士（IASOS）与Michael Wall先生（塔斯马尼亚大学地理与环境研究学院荣誉学生）。
该辐射计配备一根25米长的石英光导管，末端搭载余弦传感器附件。开展紫外辐照度测量时，需将传感器感应面水平放置，采集到的光线将通过光导管传输至辐射计——这是一台手提箱大小的便携设备，野外作业时依靠电池供电。辐射计被置于内衬聚苯乙烯泡沫的木箱中，以抵御恶劣环境并起到隔热作用。辐射计通过笔记本电脑进行控制，数据存储于PC的硬盘中。

### 测量实施
研究人员在冰缘与湖泊测量点位开展了紫外与可见光辐射随水体波长变化的衰减测量。在冰缘区域，光导管会通过滚轮放线，并下放至预设水深（通常为水面下1、2、4、8、16及32米）。在湖泊点位，则先使用25厘米口径的螺旋钻钻孔，再手动将光导管下放至不同深度，具体水深根据湖泊实际深度确定。若湖泊冰况允许，会通过钻孔下放支架，将光导管抵在冰盖下表面，以此测量海冰的紫外与可见光透射率。所有测量环节前后，均会采集紫外与可见光的地表辐照度数据。
当天空条件足够晴朗时，研究人员会使用遮光装置估算紫外与可见光辐照度的直射分量与漫射分量：此时辐射计仅测量辐射场的漫射分量，通过将全局（无遮光）测量值减去漫射分量，即可得到直射分量。部分场景下，研究人员还会测量积雪或冰面的上行辐照度，以此获取地表光谱反照率信息。

每次测量通常采集两个光谱范围的光谱辐照度数据：UV-B波段（280~400 nm，步长1 nm）与可见光波段（400~700 nm，步长5 nm）。部分场景下波长范围会有所调整——例如UV-B波段采用280~350 nm，可见光波段采用550~680 nm，对应美国国家海洋和大气管理局（NOAA）AVHRR传感器的1号通道。数据以原始数据文件形式由PC存储，文件名由日志PC的时间自动生成，格式为"hhmmss.dti"。需注意，该PC运行的是澳大利亚东部夏令时，比DLT快4小时。后续这些数据文件会被导入Excel电子表格进行处理。

更多详细信息请参阅关联报告。
本次测量的单位均为瓦每平方米每纳米（W·m⁻²·nm⁻¹）。
UV-B波段指采集的光谱范围为紫外波段（280~400 nm）；AVHRR波段指采集的光谱范围为可见光波段（400~700 nm）。
本数据集包含以下字段：紫外辐射、波长、深度、AVHRR。