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提升了该区域到达地球表面的紫外线B（UVB）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。本研究明确了南极紫外线气候特征、从分子到群落水平的紫外线生物响应，并结合上述要素预测南极海洋微生物学领域由紫外线诱导的变化。
1994年11月至12月，研究团队在戴维斯站（Davis Station）开展了一季野外工作，旨在对固定冰环境以及韦斯特福尔德丘陵（Vestfold Hills）区域的部分湖泊中的紫外线辐射进行野外实测。

## 仪器设备
本次实测所用仪器为塔斯马尼亚大学地理与环境研究系所属的Macam光谱辐射计。野外工作人员为Kelvin Michael博士（隶属于IASOS）以及Michael Wall先生（塔斯马尼亚大学地理与环境研究系荣誉学士在读，UTas）。
该辐射计配备了一根25米长的石英光导，末端装有余弦传感器附件。开展紫外线辐照度测量时，需将传感器调整至感应面水平，采集的光线将沿光导传输至辐射计——这是一台手提箱大小的野外便携设备，由电池供电。辐射计被封装在内衬聚苯乙烯泡沫的木箱中，以抵御恶劣天气并起到隔热作用。该辐射计通过笔记本电脑进行控制，数据存储于电脑的硬盘中。

## 实测方案
针对冰缘与湖泊测点，开展了水体中紫外线与可见光辐射随波长变化的衰减量实测。在冰缘区域，光导被缠绕在滚轮上，下放至预设水深（通常为水面下1、2、4、8、16及32米）。在湖泊测点，先钻取25厘米直径的螺旋钻孔，再手动将光导下放至不同深度，具体深度视湖泊实际水深而定。若湖冰条件允许，将框架通过钻孔下放，用于将光导抵靠在冰盖下表面，以此测量海冰的紫外线与可见光透射率。所有测点均会在水下测量之前及/或之后，采集表层紫外线与可见光辐照度数据。当天空晴朗度足够时，通过遮光装置估算紫外线与可见光辐照度的直射分量与漫射分量：该装置可确保辐射计仅测量辐射场的漫射分量，随后通过总辐照度（未遮光状态下的测量值）减去漫射分量，即可得到直射分量。部分场景下，还会测量积雪或冰面的上行辐照度，以获取该表面的光谱反照率信息。
每次实测通常采集两个光谱区间的光谱辐照度数据：紫外线B（UVB，280~400 nm，步长1 nm）与可见光（400~700 nm，步长5 nm）。部分场景下的波长区间会有所不同——例如紫外线B区间为280~350 nm，可见光区间为550~680 nm（对应美国国家海洋和大气管理局（NOAA）先进甚高分辨率辐射计（Advanced Very-High-Resolution Radiometer, AVHRR）的1通道）。电脑将数据以原始数据文件的形式存储，文件名由日志电脑的时间自动生成为"hhmmss.dti"格式。需注意，该电脑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。
详细信息请参阅关联报告。
所有实测数据的单位均为瓦每平方米每纳米（W·m⁻²·nm⁻¹）。
UV-B表头表示该数据采集自光谱的紫外线波段（280~400 nm）。
AVHRR表头表示该数据采集自光谱的可见光波段（400~700 nm）。
本数据集的字段如下：紫外线辐射、波长、深度、AVHRR