Based on the Landsat 5TM/7ETM+/8OLI surface reflectance collection of remote sensing images, LEDAPS and LaSRC algorithms were used for atmospheric radiation correction, and the effects of clouds, snow, etc. were removed by CFMASK algorithm. Then, the NDVI values of each image were calculated using the red and near-infrared bands, and finally the maximum NDVI value of each pixel in the Qilian Mountains area was synthesized from May to September each year. This dataset has a spatial resolution of 30 meters and synthesizes one image per year. The Landsat 5 NDVI time series is from 1986 to 2011, the Landsat 7 NDVI time series is from 1999 to 2019, and the Landsat 8 NDVI time series is from 2013 to 2019. This dataset is L1 level data and can be used for large-scale vegetation index time series comparative analysis.
The source data consists of Landsat 5 TM images, Landsat 7 ETM+images, and Landsat 8 OLI images, with a spatial resolution of 30 m
(1) Based on remote sensing images from Landsat 5/7/8 surface reflectance sets, LEDAPS and LaSRC algorithms were used for atmospheric radiation correction; (2) Remove the influence of clouds, snow, etc. through the CFMASK algorithm, and then calculate the NDVI values of each image through the red and near-infrared bands; (3) Finally, the maximum NDVI value of each pixel in the Qilian Mountains region from April to October each year was synthesized, with a valid range of -1-1.
Due to the impact of Landsat source image quality, there are some missing images in this dataset. Landsat LT05 data: There were missing bands between 1986 and 1989, normal data between 1990 and 2000, missing bands between 2001 and 2002, basically normal data between 2003 and 2011, and no relevant data after the Landsat 5 TM sensor broke down in November 2011. Landsat LT07 data: The data was normal from 1999 to 2002. However, since May 2003, the Landsat 7 ETM+sensor scan line corrector (SLC) has malfunctioned, resulting in data bands that require interpolation. The Landsat 7 satellite will be retired in 2020. Landsat LT08 data: Normal data since 2013. This dataset is L1 level data. To obtain more accurate data results, it is necessary to combine DEM and elevation data from measured points for further calibration.
| # | number | name | type |
| 1 | 2021ZDKT0004 | other |
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CSTR:11738.11.ncdc.qlsst.2020.19
10.12072/ncdc.qlsst.db0009.2020