A new index based on solar-induced chlorophyll fluorescence and land surface temperature to monitor drought

Drought is a frequent global phenomenon. The occurrence of drought can affect the production of industry, agriculture and economic growth. Solar-induced chlorophyll fluorescence is a by-product of photosynthesis that can be used to monitor vegetation growth and drought. Traditional drought monitoring generally used solar-induced chlorophyll fluorescence anomalies and rarely used solar-induced chlorophyll fluorescence to establish an index. This study integrated solar-induced chlorophyll fluorescence and land surface temperature to establish a new solar-induced chlorophyll fluorescence drought index (SIF_DI). The new SIF_DI was subsequently used for monitoring drought in Huang-Huai-Hai plain from 2000 to 2018. Results showed that SIF_DI had negative correlation with areas affected by drought. In Hebei, Henan and Shandong provinces, the correlation coefficients were − 0.79, -0.54 and − 0.76 respectively. SIF_DI had positive correlation with crop yields (wheat and maize). The correlation coefficients were 0.47, 0.61, 0.32 (wheat) and 0.69, 0.49, 0.36 (maize) respectively. All correlation coefficients surpassed those calculated using vegetation health index. Subsequently, the SIF_DI was applied to long-term drought monitoring during the crop growing season in Huang-Huai-Hai plain. This investigation proved that the new index calculated using solar-induced chlorophyll fluorescence is a reliable and effective indicator for monitoring and assessing drought.