Long-Term Arctic Growing Season NDVI Trends from GIMMS 3g, 1982-2012

This data set provides normalized difference vegetation index (NDVI) data for the arctic growing season derived primarily with data from Advanced Very High Resolution Radiometer (AVHRR) sensors onboard several NOAA satellites over the years 1982 through 2012. The NDVI data, which show vegetation activity, were averaged annually for the arctic growing season (GS; June, July and August). The products include the annual GS-NDVI values and the results of a cumulative GS-NDVI time series trends analysis. The data are circumpolar in coverage at 8-km resolution and limited to greater than 20 degrees N.

These normalized difference vegetation index (NDVI) trends were calculated using the third generation data set from the Global Inventory Modeling and Mapping Studies (GIMMS 3g). GIMMS 3g improves on its predecessor (GIMMS g) in three important ways. First, GIMMS 3g integrates data from NOAA-17 and 18 satellites to lengthen its record. Second, it addresses the spatial discontinuity north of 72 degrees N, by using SeaWiFS, in addition to SPOT VGT, to calibrate between the second and third versions of the AVHRR sensor (AVHRR/2 and AVHRR/3). Finally, the GIMMS 3g algorithm incorporates improved snowmelt detection and is calibrated based on data from the shorter, arctic growing season (May-September) rather than the entire year (January-December).

本数据集提供了北极生长季节（六月、七月和八月）的标准化植被指数（NDVI）数据，这些数据主要源自1982年至2012年间多颗NOAA卫星上搭载的先进甚高分辨率辐射计（AVHRR）传感器。该NDVI数据展示了植被活动，并按年度对北极生长季节进行了平均。产品包括年度GS-NDVI值以及累积GS-NDVI时间序列趋势分析结果。数据覆盖全球，以8公里分辨率为标准，且限于北纬20度以上区域。这些标准化植被指数（NDVI）趋势是通过使用全球存货建模和制图研究（GIMMS 3g）第三代数据集进行计算的。GIMMS 3g在三个方面优于其前身（GIMMS g）。首先，GIMMS 3g整合了NOAA-17和18卫星的数据，从而延长了数据记录的长度。其次，通过使用SeaWiFS以及SPOT VGT，解决了72度以北的空间不连续性问题，以校准AVHRR传感器（AVHRR/2和AVHRR/3）的第二版和第三版之间。最后，GIMMS 3g算法融合了改进的积雪融化检测技术，并且基于较短的北极生长季节（五月至九月）的数据而非全年（一月到十二月）进行校准。