兰州大学寒旱区科学观测网络CARN（苏干湖站物候相机观测数据集-2021）

该数据集包含2021年1月1日至2021年12月31日柴达木盆地哈尔腾河流域兰州大学寒旱区科学观测网络苏干湖站的物候相机观测数据，观测点的经纬度是94.125°E，38.992N，海拔2798m。该数据使用北京师范大学自主研发的软件包进行处理。该物候相机采用向下的方式采集数据，拍摄数据分辨率为2592*1944，可指定拍摄时间频率。对于绿度指数物候期计算，需要根据感兴趣区域计算相对绿度指数（GCC, Green Chromatic Coordinate公式为GCC=G/(R+G+B), R、G、B为图像红、绿、蓝三通道像元值），然后进行无效值填充和滤波平滑，最后根据生长曲线拟合确定关键物候期参数，如生长季起始日、顶峰、生长季结束日等；对于覆盖度，首先进行数据预处理，选择光照不太强的图像，然后将图像分割为植被和土壤，计算每张图像的植被像素占计算区域内的比例作为该图像对应的覆盖度，在时间序列数据提取完成以后，再按用户指定的时间窗口对原始覆盖度数据进行平滑滤波，滤波后的得结果为最终的时间序列覆盖度。本数据集包括相对绿度指数（GCC）。该站点物候相机于2021年8月12日调整过拍摄角度。

This dataset contains phenological camera observation data from the Sugan Lake Station of the Cold and Arid Regions Science Observation Network of Lanzhou University in the Halteng River Basin, Qaidam Basin, spanning from January 1, 2021 to December 31, 2021. The coordinates of the observation site are 94.125°E, 38.992°N, with an altitude of 2798 m. This data was processed using a software package independently developed by Beijing Normal University. The phenological camera collects data in a downward-facing configuration, with a shooting resolution of 2592×1944, and the shooting time interval can be specified. For phenological phase calculation based on greenness index, the relative Green Chromatic Coordinate (GCC, with the formula GCC=G/(R+G+B), where R, G, and B represent the pixel values of the red, green, and blue channels of the image respectively) should be calculated based on the region of interest. Subsequently, invalid value filling and filtering smoothing are conducted, and finally key phenological phase parameters such as the start date of the growing season, peak value, and end date of the growing season are determined via growth curve fitting. For vegetation coverage calculation, data preprocessing is first performed by selecting images with moderate light intensity. Then, the image is segmented into vegetation and soil components, and the proportion of vegetation pixels within the calculated region of each image is calculated as the coverage corresponding to that image. After the time series data is extracted, smoothing filtering is applied to the original coverage data according to the user-specified time window, and the filtered result serves as the final time series coverage product. This dataset includes the relative Green Chromatic Coordinate (GCC). The phenological camera at this station had its shooting angle adjusted on August 12, 2021.