Mutual Use of SGLI- and MODIS-derived Land Surface Temperature for Croplands

Land surface temperature (LST) monitoring is used to detect agro-meteorological events, such as drought and cold weather, to assess crop growth and production. LST products derived from the Second Generation Global Imager (SGLI) onboard the Global Change Observation Mission-Climate (GCOM-C) satellite are provided by the Japan Aerospace Exploration Agency (JAXA). GCOM-C was launched on 23 December 2017, and LST data with 250 m spatial resolution have been available since January 2018. Drought or cold weather is detectable as an anomalous event when LST data for the target period is compared with previous long-term data. However, SGLI/LST data have not been archived over the long term, so a comparison requires data from other sources. On the other hand, MODIS on the Terra satellite has operated for almost 20 years already, and how long continuing useful data can be expected is uncertain. Thus, its data compatibility with other sensors must be assessed to create a comprehensive long-term dataset. The mutual use of SGLI and MODIS LST products would be ideal.This report compares SGLI/LST (level 3, version 2) images of cropland with the corresponding MODIS/LST (MOD11C1, C6) ones. Comparing a variety of acreage in the world has shown that, for LST above 290 K, SGLI/LST estimates LST at a higher value than MODIS/LST. SGLI/LST data were corrected using a regression model derived from information about the comparability of SGLI/LST and MODIS/LST cropland data to reduce the differences between the data from both sources. This was done on a global scale. Spatially averaged LSTs were also calculated from corrected SGLI/LST and MODIS/LST for six provinces and main croplands in the world. The time-series changes in these data were compared. These products showed a high correlation in time-series changes; the average differences in LSTs for the five provinces ranged from -1.54 to 0.84 K.