Dataset associated with the article "A new 2010 permafrost distribution map over the Qinghai-Tibet Plateau based on subregion survey maps: a benchmark for regional permafrost modelling" published on <i>Earth System Science Data</i>

Dataset descriptionThis dataset provides the data associated with the article: Cao, Z., Nan, Z., Hu, J., Chen, Y., &amp; Zhang, Y. (2022). A new 2010 permafrost distribution map over the Qinghai-Tibet Plateau based on subregion survey maps: a benchmark for regional permafrost modeling. <i>Earth System Science Data</i>This dataset contains a new 2010 permafrost distribution map over the Qinghai-Tibet Plateau and the data used in the mapping. All data are provided as GeoTIFF(.tif) files. The spatial resolution is 1 km, and the geographic coordinate system is WGS_1984.1. "permafrost_distribution_map_2010_QTP.tif" is the 2010 permafrost distribution map over the Qinghai-Tibet Plateau.2. "soil_cluster_QTP.tif" is the spatial distribution of the resulting soil clusters on the Qinghai-Tibet Plateau.3. "DDT_mean_annual.tif" contains annual thawing indices on the QTP averaged from 2005-2010 derived from MODIS LST data.4. "DDF_mean_annual.tif" contains annual freezing indices on the QTP averaged from 2005-2010 derived from MODIS LST data.AbstractPermafrost over the Qinghai–Tibet Plateau (QTP) has received increasing attention due to its high sensitivity to climate change. Numerous spatial modeling studies have been conducted on the QTP to assess the status of permafrost, project future changes in permafrost, and diagnose contributors to permafrost degradation. Due to the scarcity of ground stations on the QTP, these modeling studies are often hampered by the lack of validation references, calibration targets, and model constraints; however, a high-quality permafrost distribution map would be a good option as a benchmark for spatial simulations. Existing permafrost distribution maps for the QTP can poorly serve this purpose. An ideal benchmark map for spatial modeling should be methodologically sound, of sufficient accuracy, and based on observations from mapping years rather than all historical data spanning several decades. Therefore, in this study, we created a new permafrost distribution map for the QTP in 2010 using a novel permafrost mapping approach with satellite-derived ground surface thawing and freezing indices as inputs and survey-based subregion permafrost maps as constraints. This approach accounted for the effects of local factors by incorporating (into the model) an empirical soil parameter whose values were optimally estimated through spatial clustering and parameter optimization constrained by survey-based subregion permafrost maps. This mapping approach was also improved to reduce parametric equifinality. This new map showed a total permafrost area of about 1.086×10^6 km^2 (41.2% of the QTP area) and seasonally frozen ground of about 1.447×10^6 km^2 (54.9 %) in 2010, excluding glaciers and lakes. Validations using survey-based subregion permafrost maps (kappa = 0.74) and borehole records (overall accuracy = 0.85 and kappa = 0.43) showed a higher accuracy of this map compared with two other recent maps. Inspection of regions with obvious distinctions between the maps affirms that the permafrost distribution on this map is more realistic than that on the Zou et al. (2017) map. Given the demonstrated excellent accuracy, this map can serve as a benchmark map for constraining/validating land surface simulations on the QTP and as a historical reference for projecting future permafrost changes on the QTP in the context of global warming.数据集说明 本数据集关联于以下学术论文：Cao, Z., Nan, Z., Hu, J., Chen, Y., & Zhang, Y. (2022). 基于分区调查图的青藏高原2010年全新冻土分布图：区域冻土模拟基准。<i>《地球系统科学数据》</i> 本数据集包含青藏高原2010年冻土分布图及制图所用相关数据，所有数据均以GeoTIFF（.tif）格式提供。数据集空间分辨率为1千米，地理坐标系为WGS_1984。 1. "permafrost_distribution_map_2010_QTP.tif"：青藏高原2010年冻土分布图。 2. "soil_cluster_QTP.tif"：青藏高原研究区所得土壤集群的空间分布数据。 3. "DDT_mean_annual.tif"：基于2005-2010年MODIS地表温度（Land Surface Temperature, LST）数据计算得到的青藏高原年均解冻指数数据。 4. "DDF_mean_annual.tif"：基于2005-2010年MODIS地表温度（Land Surface Temperature, LST）数据计算得到的青藏高原年均冻结指数数据。 摘要 青藏高原（Qinghai–Tibet Plateau, QTP）多年冻土（permafrost）对气候变化高度敏感，相关研究受到广泛关注。学界已针对青藏高原开展大量空间模拟研究，以评估冻土现状、预测冻土未来变化及解析冻土退化驱动因子。但由于青藏高原地面观测站稀缺，此类模拟研究常因缺乏验证参考、校准目标与模型约束而受阻，而高质量冻土分布图可作为空间模拟的基准数据集，弥补这一短板。现有青藏高原冻土分布图难以满足此类需求。理想的模拟基准地图应具备方法严谨、精度充足，且制图数据基于对应年份的观测资料而非数十年的历史全域数据。因此，本研究采用全新的冻土制图方法，以卫星反演的地表解冻与冻结指数为输入变量，以基于调查的分区冻土图作为约束条件，构建了2010年青藏高原全新冻土分布图。该方法通过引入经验性土壤参数并结合空间聚类与基于调查分区冻土图约束的参数优化，实现了局地因子影响的考量，同时优化了模型以降低参数等价性问题。 本新分布图结果显示：2010年青藏高原多年冻土总面积约为1.086×10^6 平方千米（占青藏高原总面积的41.2%），季节冻土（seasonally frozen ground）总面积约为1.447×10^6 平方千米（占54.9%），统计范围未包含冰川与湖泊。通过基于调查的分区冻土图（Kappa系数=0.74）与钻孔记录（总体精度=0.85，Kappa系数=0.43）开展验证，结果表明本数据集的制图精度优于其他两款近期发布的冻土分布图。对各分布图间存在显著差异的区域进行检视后确认，本数据集的冻土分布相较于Zou等人（2017）发布的地图更符合实际情况。鉴于本数据集已验证的优异精度，其可作为约束或验证青藏高原陆面模拟的基准数据集，同时可为全球变暖背景下青藏高原冻土未来变化的预测研究提供历史参考基准。