Global SnowPack - MODIS - Mean

This product shows the mean snow cover duration (SCDmean), which is updated each year and consists of the arithmetic mean for the entire time series since the hydrological year 2001. The hydrological year begins in the meteorological autumn (October 1 of the previous year in the northern hemisphere or March 1 of the reference year in the southern hemisphere) and ends with the meteorological summer (northern hemisphere: August 31 of the reference year; southern hemisphere: February 28/29 of the following year). Analogous to the annual products for snow cover duration, the entire year as well as the early season (until mid-winter) and the late season (from mid-winter) are taken into account here. The “Global SnowPack” is derived from daily, operational MODIS snow cover product for each day since February 2000. Data gaps due to polar night and cloud cover are filled in several processing steps, which provides a unique global data set characterized by its high accuracy, spatial resolution of 500 meters and continuous future expansion. It consists of the two main elements daily snow cover extent (SCE) and seasonal snow cover duration (SCD; full and for early and late season). Both parameters have been designated by the WMO as essential climate variables, the accurate determination of which is important in order to be able to record the effects of climate change. Changes in the largest part of the cryosphere in terms of area have drastic effects on people and the environment. For more information please also refer to: Dietz, A.J., Kuenzer, C., Conrad, C., 2013. Snow-cover variability in central Asia between 2000 and 2011 derived from improved MODIS daily snow-cover products. International Journal of Remote Sensing 34, 3879–3902. https://doi.org/10.1080/01431161.2013.767480 Dietz, A.J., Kuenzer, C., Dech, S., 2015. Global SnowPack: a new set of snow cover parameters for studying status and dynamics of the planetary snow cover extent. Remote Sensing Letters 6, 844–853. https://doi.org/10.1080/2150704X.2015.1084551 Dietz, A.J., Wohner, C., Kuenzer, C., 2012. European Snow Cover Characteristics between 2000 and 2011 Derived from Improved MODIS Daily Snow Cover Products. Remote Sensing 4. https://doi.org/10.3390/rs4082432 Dietz, J.A., Conrad, C., Kuenzer, C., Gesell, G., Dech, S., 2014. Identifying Changing Snow Cover Characteristics in Central Asia between 1986 and 2014 from Remote Sensing Data. Remote Sensing 6. https://doi.org/10.3390/rs61212752 Rößler, S., Witt, M.S., Ikonen, J., Brown, I.A., Dietz, A.J., 2021. Remote Sensing of Snow Cover Variability and Its Influence on the Runoff of Sápmi’s Rivers. Geosciences 11, 130. https://doi.org/10.3390/geosciences11030130本产品展示平均积雪时长（mean snow cover duration, SCDmean），该数据集每年更新，其取值为2001水文年以来完整时间序列的算术平均值。水文年的起始时间为气象秋季：北半球为上一年的10月1日，南半球为参考年份的3月1日；终止时间为气象夏季：北半球为参考年份的8月31日，南半球为次年的2月28/29日。与积雪时长年度产品一致，本数据集同时考虑了全年、早季（至仲冬）以及晚季（自仲冬起）的积雪情况。 “全球积雪数据集（Global SnowPack）”源自2000年2月以来每日运行的中分辨率成像光谱仪（Moderate Resolution Imaging Spectroradiometer, MODIS）积雪覆盖产品。针对极夜与云覆盖造成的数据空白，研究团队通过多步处理流程完成填补，最终得到了兼具高精度、500米空间分辨率且可持续未来更新的独特全球数据集。该数据集包含两大核心参数：每日积雪范围（daily snow cover extent, SCE）以及季尺度积雪时长（seasonal snow cover duration, SCD，涵盖全年、早季与晚季）。上述两项参数已被世界气象组织（World Meteorological Organization, WMO）列为气候关键变量，精准测算这两项参数对于记录气候变化影响至关重要。占冰冻圈主体的积雪面积变化，会对人类社会与自然环境造成剧烈影响。 如需了解更多信息，亦可参考以下文献： 1. Dietz, A.J., Kuenzer, C., Conrad, C., 2013. 《基于改进型MODIS每日积雪覆盖产品的2000-2011年中亚积雪变化》. *International Journal of Remote Sensing*, 34, 3879–3902. https://doi.org/10.1080/01431161.2013.767480 2. Dietz, A.J., Kuenzer, C., Dech, S., 2015. 《全球积雪数据集：用于研究行星积雪覆盖范围状态与动态的新型积雪参数集》. *Remote Sensing Letters*, 6, 844–853. https://doi.org/10.1080/2150704X.2015.1084551 3. Dietz, A.J., Wohner, C., Kuenzer, C., 2012. 《基于改进型MODIS每日积雪覆盖产品的2000-2011年欧洲积雪特征》. *Remote Sensing*, 4. https://doi.org/10.3390/rs4082432 4. Dietz, J.A., Conrad, C., Kuenzer, C., Gesell, G., Dech, S., 2014. 《基于遥感数据识别1986-2014年中亚积雪特征变化》. *Remote Sensing*, 6. https://doi.org/10.3390/rs61212752 5. Rößler, S., Witt, M.S., Ikonen, J., Brown, I.A., Dietz, A.J., 2021. 《积雪变化遥感监测及其对萨米河径流的影响》. *Geosciences*, 11, 130. https://doi.org/10.3390/geosciences11030130