A standardized index for assessing sub-monthly compound dry and hot conditions

Understanding the compound dry and hot events is very important to human being society and environments.This study proposes a new compound drought and heat index on daily scale, SCDHI, based on SAPEI and STI.This index is useful to quantify sub-monthly characteristics of compound dry and hot events.The topic is very interesting and suitable for HESS.I recommend the manuscript for acceptance with a minor revision.The detailed comments are provided below:1) This study focuses the non-arid areas in China.Is SCDHI suitable for the arid areas?2) There was a similar index for characterizing CDHEs (Hao et al., 2020).I suggest the authors to discuss the difference between this study and the study of Hao et al. (2020), and highlight the novelty of this study in the Introduction section.