A worldwide wolverine distribution model based on late-spring snow cover from 2000-2006

This data publication contains raster datasets (GeoTiff format) developed using MODIS (Moderate Resolution Imaging Spectroradiometer) classified satellite images for 24 April to 15 May from 2000 to 2006 to depict persistent snow cover occurring at the end of the wolverine's reproductive denning period throughout the circumboreal region. There are 3 grids contained in this package, each of which corresponds to a distinct portion of the region: (1) North America, (2) Scandinavia and Eurasia, and (3) Southern Europe. Each MODIS image was re-classified into 4 cover classes (snow, bare ground, cloud, night) for each of the 7 years. A portion of each daily MODIS image was typically obscured by clouds or, occasionally, by night. Generating cloud- and night-free images required compositing the 21 consecutive daily images from 24 April to 15 May. If grid cells were classified as bare ground for any day within this time period, they were retained as bare ground in the final coverage. This resulted in a final late-spring snow cover layer that was limited to areas with snow cover that persisted through 15 May. We then summed all annual snow layers for the 7-year period to create a coverage that depicted the number of years out of 7 that each pixel was classified as snow (hereafter, the late-spring snow coverage). Regions of persistent glaciation (e.g., Greenland), and arctic regions >=80° N latitude, were excluded from the late-spring snow coverage due to predictably consistent snow cover during that time of year.
These coverages were created for the purpose of investigating correlations between the geographic distribution of late-spring snow cover and the geographic distribution of wolverines throughout the circumboreal region during the period of time that encompasses the end of the wolverine's reproductive denning period.
The results of this research are presented in Copeland et al. (2010) and users of this raster dataset should refer to that publication for additional details.

These data were published on 07/02/2024. Minor metadata updates were made on 07/30/2024.

本数据集出版物包含基于MODIS（中分辨率成像光谱仪，Moderate Resolution Imaging Spectroradiometer）分类卫星影像生成的GeoTiff格式栅格数据集，时间覆盖2000年至2006年每年的4月24日至5月15日，用于描绘环北极地区狼獾生殖育幼期结束时持续存在的积雪覆盖范围。
本数据包包含3个栅格，分别对应环北极地区的三个独立分区：(1) 北美区域；(2) 斯堪的纳维亚与欧亚大陆区域；(3) 南欧区域。
针对7年研究期内的每一年，每张原始MODIS影像均被重分类为4种覆盖类型：积雪、裸地、云、夜间像元。由于每日MODIS影像通常存在部分区域被云遮挡的情况，偶尔还会受夜间成像影响，因此需要合成该时段（4月24日至5月15日）连续21天的影像，以生成无云且无夜间干扰的最终影像。若某栅格单元在该时段内任意一天被分类为裸地，则其在最终覆盖层中仍保留裸地分类。经上述处理后得到的晚春积雪覆盖层，仅包含持续至5月15日的积雪区域。
随后我们对7年的年度积雪图层进行求和，生成一幅覆盖图层，用于表征每个像元在7年研究期内被分类为积雪的年数（以下简称晚春积雪覆盖度）。由于格陵兰等常年冰川区域以及北纬80°及以上的北极区域在该时段的积雪状况可预测且常年稳定，因此将其从晚春积雪覆盖度图层中剔除。
本覆盖图层的制作目的为探究环北极地区晚春积雪覆盖的地理分布与狼獾地理分布之间的相关性，该时段覆盖了狼獾生殖育幼期的末期。
本研究的成果已发表于Copeland等人2010年的研究文献中，使用该栅格数据集的用户请参考该文献以获取更多细节信息。
本数据集于2024年7月2日正式发布，并于2024年7月30日完成了元数据的小幅更新。