The combined effect of drought and salinity on crops is very important for food security under global change background. Remote sensing shows its advantage for large-scale applications. This paper used the sentinel-2 satellite data to conduct an analysis in this regard. The findings are interesting. I have the following major concerns:

Major:

1) Irrigation can mitigate the drought effect to a large extent. I would like to know how irrigation has influenced the analysis. There is no information reported in this regard.

2) Five different indicators were used to depict the health condition of different crops. I am wondering how the stress factors influence the final yield. Is it possible to have some discussion in this regard?

Moreover, please find below some minor comments:

Line 33, more deeply challenged.

Line 37, delete ‘of’ and ‘more than’

Lines 83-90, why was SPEI selected as the drought indicator rather than the others? What is the RD_new projection? Where are the precipitation and PET data from?

Lines 124-129, Include some information about Sentinel-2 in the data description although it was pointed out in Fig. 1.

Line 145, why was the biomass effect removed? Is this contradictory to the Cab*LAI and Cw*LAI at Line 142?

Line 151, What do you mean by ‘due to the unbalance in the occurrence of stress conditions‘?

Lines 163-173, More explanations are needed to illustrate the connotations of different indicators in the ANOVA analysis, to increase the readability. Probably this can be supplemented in the methodology section.

Line 200, Add some information for the different letters indicating the significance level.

Line 220 and Line 244, It was concluded at Line 220 that there is no additive effect for drought and salinity. Is it in contradiction to the severe effect of the co-occurrence of drought and salinity?

Line 257, why was the drought effect mitigated? Please add more explanations.

Line 278, ‘Considering the additional’, remove the comma. Change ‘promising’ to ‘probable’.

Line 283, ‘In addition to facilitating the evaluation…’

Line 285, distinctively

Line 288, understand

Line 289, as compared to

Line 291, In this respect

Line 292, the transpiration demand normally refers to the atmospheric demand, like VPD and incoming radiation. What do you mean here?

Please check the English writing more carefully to enhance the readability.

Drought and salinity are considered to be the two main factors limiting crop productivity. Remote sensing enables the assessment of the impacts of extremes on crops, but it is seldomly used in the study of compound effects of drought and salinity stress. The novelty of this study is to assess the impacts of drought, salinity, and their combination on crop traits using multiple remote sensing observations and explore their relationships with stress timings and drought levels. The manuscript makes a contribution to the assessment of compound extremes’ impacts using remote sensing and the writing is well organized. I suggest this manuscript should be accepted by HESS after minor revisions.

Specific comments:

1. In this study, only the 2018 case over the Netherlands was analyzed, are the conclusions robust? As the available data range from 2004 to 2018, are there any else cases to verify the conclusions? If there is no more cases, it is better to add the name of this case in the title.
2. Add a map of the crop distribution over the study region.
3. Line 89-90: The standard deviation of SPEI is 1 (Vicente-Serrano et al 2010), why do you define drought when SPEI is less than -321?
4. The captions of Table 1, figure 3, and figure 4 should be described in detail, e.g. what are MD, MS, SS, ab, and abc short for in fig. 3?
5. As figures 3-4 show the values of crop traits from May to September, it is better to show their standardized anomalies compared with climatology, which enables the comparison between different timings.
6. What is the best explanation of the different responses among the five crop traits to such stresses?