A fractional vegetation cover remote sensing product on pan-arctic scale with link to GeoTIFF image

The paper presents first results of a pan-boreal scale land cover harmonization and classification. A methodology is presented that combines global and regional vegetation datasets to extract percentage cover information for different vegetation physiognomy and barren for the pan-arctic region within the ESA Data User Element Permafrost. Based on the legend description of each land cover product the datasets are harmonized into four LCCS (Land Cover Classification System) classifiers which are linked to the MODIS Vegetation Continuous Field (VCF) product. Harmonized land cover and Vegetation Continuous Fields products are combined to derive a best estimate of percentage cover information for trees, shrubs, herbaceous and barren areas for Russia. Future work will concentrate on the expansion of the developed methodology to the pan-arctic scale.
Since the vegetation builds an isolation layer, which protects the permafrost from heat and cold temperatures, a degradation of this layer due to fire strongly influences the frozen conditions in the soil. Fire is an important disturbance factor which affects vast processes and dynamics in ecosystems (e.g. biomass, biodiversity, hydrology, etc.). Especially in North Eurasia the fire occupancy has dramatically increased in the last 50 years and has doubled in the 1990s with respect to the last five decades. A comparison of global and regional fire products has shown discrepancies between the amounts of burn scars detected by different algorithms and satellite data.

本论文报道了泛北方林带尺度土地覆盖协调与分类的首批研究成果。本文提出了一种融合全球与区域植被数据集的方法，用于提取隶属于欧洲空间局（ESA）永久冻土数据用户要素项目的泛北极区域内，不同植被外貌与裸地的覆盖百分比信息。基于各土地覆盖产品的图例描述，本次研究将多套数据集协调归类至4个土地覆盖分类系统（Land Cover Classification System, LCCS）分类器中，这些分类器与中分辨率成像光谱仪（Moderate Resolution Imaging Spectroradiometer, MODIS）植被连续场（Vegetation Continuous Field, VCF）产品相关联。将经协调后的土地覆盖与植被连续场产品进行融合，以估算俄罗斯区域内林木、灌丛、草本植被及裸地的覆盖百分比最优值。后续研究将致力于将所提出的方法推广至泛北极尺度。
由于植被构成了隔热层，可保护永久冻土免受极端冷热温度的影响，因此火灾引发的该隔热层退化会显著改变土壤的冻结状态。火灾是一类重要的生态干扰因子，会对生态系统的诸多过程与动态（如生物量、生物多样性、水文循环等）产生影响。尤其在北欧亚地区，近50年来火灾过火面积大幅增长，1990年代的过火面积相较前50年翻倍。对全球及区域火灾监测产品的对比分析显示，不同算法与卫星数据所探测到的火烧疤痕数量存在显著差异。