A history reconstructed time series (1992-2011) of annual global NPP-VIIRS-like nighttime light data through a super-resolution U-Net model

The dataset is an extend time series of the Version 2 annual NPP-VIIRS nighttime light composites. The dataset contains (1) simulated NPP-VIIRS NTL time series from the DMSP-OLS NTL data (1992-2011) based on a super-resolution U-Net method; and (2) the version 2 annual NPP-VIIRS NTL data (2012-2020), which were obtained from the academic sector at the Colorado School of Mines (https://eogdata.mines.edu/products/vnl/). The pixels of which value less than zero were set to zero. The dataset are 15 arc second grids, spanning -180 to 180 degrees longitude and -65 to 75 degrees latitude. Each zip file contains an NTL image in geotiff format. The filename of each image is "SRUNet_NPP_VIIRS_V2_Like_yyyy", where "yyyy" is the year of the image. The simulated NPP-VIIRS NTL data converted from the DMSP-OLS NTL data in 2012 and 2013 are also uploaded, which named "simulated_NPP_VIIRS_V2_yyyy". Based on the super-resolution deep learning technology, the dataset using DMSP-OLS NTL data and Landsat NDVI to reconstruct the NPP-VIIRS NTL data in the early years (1992-2011). The dataset could be easily updated by downloading the version 2 annual NPP-VIIRS NTL data in later years from the academic sector at the Colorado School of Mines (https://eogdata.mines.edu/products/vnl/). The dataset has good spatial pattern and temporal consistency, and is highly consistent with NPP-VIIRS NTL data. It provide a longer time period compared to existing products. Compared with the annual NPP-VIIRS NTL data in 2012, the dataset shows a good consistency at the pixel, city, province and nation levels with R2 of 0.617, 0.747, 0.874, and 0.964, respectively, while the R2 of the NPP-VIIRS-like NTL product provide by Chen (2020) is 0.512, 0.694, 0.86, and 0.966, respectively.本数据集为NPP-VIIRS夜间灯光年度合成数据第2版（Version 2）的扩展时间序列数据集。 本数据集包含两类数据：(1) 基于超分辨率U-Net（super-resolution U-Net）方法，由DMSP-OLS夜间灯光（Nighttime Light, NTL）数据（1992-2011年）生成的模拟NPP-VIIRS NTL时间序列；(2) 2012-2020年的NPP-VIIRS NTL年度合成数据第2版，该数据取自科罗拉多矿业学院（Colorado School of Mines）学术数据集（https://eogdata.mines.edu/products/vnl/）。所有数值小于0的像元均被置为0。 本数据集采用15角秒网格，覆盖经度范围-180°至180°，纬度范围-65°至75°。 每个压缩包均包含一个GeoTIFF格式的NTL影像，影像文件命名格式为"SRUNet_NPP_VIIRS_V2_Like_yyyy"，其中"yyyy"代表影像对应的年份。 此外本数据集还上传了2012年、2013年由DMSP-OLS NTL数据转换得到的模拟NPP-VIIRS NTL数据，其文件命名格式为"simulated_NPP_VIIRS_V2_yyyy"。 本数据集基于超分辨率深度学习技术，利用DMSP-OLS NTL数据与Landsat NDVI数据，重构了1992-2011年早期的NPP-VIIRS NTL数据。用户可通过下载科罗拉多矿业学院学术数据集后续年份的NPP-VIIRS NTL年度合成数据第2版，轻松实现本数据集的更新。该数据集具备优良的空间格局与时间一致性，与真实NPP-VIIRS NTL数据高度匹配，相较于现有同类产品拥有更长的时间序列跨度。 以2012年NPP-VIIRS NTL年度合成数据为基准，本数据集在像元、城市、省份及国家尺度上均表现出良好的一致性，对应决定系数R²分别为0.617、0.747、0.874和0.964；而Chen（2020）发布的类NPP-VIIRS NTL产品在对应尺度上的R²分别为0.512、0.694、0.86和0.966。