NPP/VIIRS Atmospherically Corrected Surface Reflectance 6-Min L2 Swath 375m, 750m

The VNP09_NRT is a Near Real Time (NRT) S-NPP/VIIRS 375 m, 750 m Atmospherically Corrected Surface Reflectance product. The NPP/VIIRS surface reflectance products are estimates of surface reflectance in each of the VIIRS reflective bands I1-I3, M1-M5, M7, M8, M10, and M11. The VNP09 Level-2 surface reflectance product contains approximately 6 minutes' worth of data. Surface reflectance for each moderate-resolution (750m) or imagery-resolution (375m) pixel is retrieved separately for the Level-2 products.

Surface reflectance is obtained by adjusting top-of-atmosphere reflectance to compensate for atmospheric effects. Corrections are made for the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm include top-of-atmosphere reflectance for the VIIRS visible bands (VNP02MOD, VNP02IMG), the VIIRS cloud mask and aerosol product (NPP-CMIP_L2), aerosol optical thickness (NPP_VAOTIP_L2, NPP_VAMIP_L2), and atmospheric data obtained from a reanalysis (surface pressure, atmospheric precipitable water, and ozone concentration).

All surface reflectance products are produced for daytime conditions only. The product is produced under all atmospheric conditions except for night and oceans. Pixels when not produced are replaced by fill values in the Level-2 and Level-2G products.

For more information read Suomi-NPP VIIRS Surface Reflectance User's Guide at https://viirsland.gsfc.nasa.gov/PDF/VIIRS_Surf_Refl_UserGuide_v1.3.pdf

or

visit VIIRS Land website at https://viirsland.gsfc.nasa.gov/index.html

VNP09_NRT乃一种近实时（NRT）的S-NPP/VIIRS 375米、750米大气校正地表反射率产品。NPP/VIIRS地表反射率产品是对VIIRS反射波段I1-I3、M1-M5、M7、M8、M10及M11中各自地表反射率的估算。VNP09二级地表反射率产品包含大约6分钟的数据。针对中等分辨率（750米）或影像分辨率（375米）的像素，在二级产品中分别提取其地表反射率。地表反射率通过调整大气顶反射率以补偿大气效应而获得。校正包括对分子气体（包括臭氧和水汽）及大气气溶胶效应的校正。地表反射率算法的输入包括VIIRS可见波段的大气顶反射率（VNP02MOD、VNP02IMG）、VIIRS云掩膜和气溶胶产品（NPP-CMIP_L2）、气溶胶光学厚度（NPP_VAOTIP_L2、NPP_VAMIP_L2）以及来自再分析的大气数据（地表气压、大气可降水量和臭氧浓度）。所有地表反射率产品仅适用于白天条件。产品在除了夜晚和海洋之外的所有大气条件下生产。未生产时的像素在二级和二级G产品中以填充值替换。欲了解更多信息，请参阅Suomi-NPP VIIRS地表反射率用户指南（https://viirsland.gsfc.nasa.gov/PDF/VIIRS_Surf_Refl_UserGuide_v1.3.pdf）或访问VIIRS陆地网站（https://viirsland.gsfc.nasa.gov/index.html）。