Albedos for 300-2500nm for thin sea ice covered with frost flowers, nilas, snow, and slush collected during SIPEX II

This dataset contains albedo data for several varieties of sea ice and snow from 300-2500 nm measured during the SIPEX II voyage (2012). An Analytical Spectral Device (ASD) spectrophotometer records the amount of radiation impingent on a cosine collector, which contains a spectralon diffuser plate. The radiation that hits the diffuser plate is scattered equally in all directions (isotropically). A portion of the radiation incident on the plate is scattered in the direction of a fiber optic cable, which is connected to the ASD. The ASD separates the incoming radiation into 3-10 nm wavelength bins, thus creating a radiation spectrum spanning 300-2500 nm. The cosine collector can be oriented both upwards towards the sky and downward towards the snow and/or sea ice to measure the spectral signature of both the downwelling (from the sky) and upwelling (from the snow/ice) radiation. For each site, we record 5 upwelling and 5 downwelling spectral signatures. MATLAB or a similar analysis package is required to open the spectrum files that are created by the ASD. The ASD files are raw files and named in a sequence, starting with 'spectrum.000'.MATLAB or similar scripts can been written to convert the ASD spectrum data to .mat files. The spectra in the processed files are used to calculate the albedos for various snow and ice types when the ratio of upwelling to downwelling radiation is computed. We use two upwelling scans per one downwelling scan to compute the albedo. Also included is some photography of frost flowers and other examples of ice that was observed.

本数据集包含2012年SIPEX II科考航次中测得的300~2500 nm波段范围内多种海冰与积雪的反照率（albedo）数据。本次航次使用搭载有Spectralon漫反射板（spectralon diffuser plate）的余弦收集器（cosine collector）的分光光度计（Analytical Spectral Device，ASD），记录入射至该收集器的辐射总量：入射至漫反射板的辐射会在全空间内均匀散射（各向同性），其中一部分辐射会沿与ASD相连的光纤方向散射。ASD可将入射辐射划分至3~10 nm的波长区间内，由此生成覆盖300~2500 nm波段的辐射光谱。该余弦收集器可朝上朝向天空，或朝下朝向积雪与/或海冰，以分别测量下行（来自天空）与上行（来自积雪/海冰）辐射的光谱特征。每个观测站点均采集5组上行光谱与5组下行光谱数据。ASD生成的原始光谱文件需使用MATLAB或同类分析软件打开，其文件按序列命名，起始名为‘spectrum.000’；可通过编写MATLAB或同类脚本将ASD光谱数据转换为.mat格式文件。当计算上行辐射与下行辐射的比值时，可利用处理后文件中的光谱数据计算不同积雪与海冰类型的反照率，本研究采用每1组下行扫描对应2组上行扫描的方式计算反照率。数据集还包含本次观测中拍摄的霜花及其他观测到的冰体样本的相关照片。