Amplification of Extreme Hot Temperatures over Recent Decades
Round 1
Reviewer 1 Report
Manuscript is good and recommended for publication.
Author Response
Thank you for the positive assessment of this work.
Reviewer 2 Report
The author aimed to investigate the amplification of extreme hot temperatures over recent decades. The overall topic has considerable importance. However, there are some points that need to be further addressed before publication, so I suggest major revision.
Line 13-14 Introduction starts with the same sentence from the abstract. Please rephrase it. It lacks the literature of climate extreme indices in regarding both assessment of observations and model performance and projections. The author should provide sufficient literature.
Line 38 Is there any reference supporting that 80th percentile is representing typical summer conditions?
The analysis of only TXX compared to Tmax80 is not sufficient to study amplification of extreme temperatures. There should be more climate extreme indices to be investigated such as 95th or 99th percentiles of maximum temperatures. (Please look at ETCDDI indices)
Line 88 please correct “intensification”.
Figure1,2 and 3 Scale and colormap should be redefined. It is hard to understand the changes as it is. Europe and Africa are divided into two pieces in the map, and it is difficult to interpret. I suggest dividing the map by 200th longitude if possible. And country borders could be nice to be added for a better representation.
Line 122 1970-2020 or 1959-2021? Please correct it.
Interpretation of results should be given in details and in terms of regions.
Line 139 a is missing in “irrigtion”.
Line 188 owas should be deleted.
Conclusion is weak and should be improved.
Author Response
> Line 13-14 Introduction starts with the same sentence from the abstract. Please rephrase it. It lacks the literature of climate extreme indices in regarding both assessment of observations and model performance and projections. The author should provide sufficient literature.
The first sentence has been rephrased. The Introduction has been expanded and more references to the literature have been added.
> Line 38 Is there any reference supporting that 80th percentile is representing typical summer conditions?
To my knowledge, this has not been explicitly stated before. Accordingly, I added a paragraph under Methods where I checked the correspondence between T80max and the distribution of summer temperatures across weather stations globally:
"The position of T80max in the summer temperature probability distribution was checked using all 4468 weather stations in the HADISD database that had at least 10 complete years of subdaily temperature data. Defining summer as the climatologically warmest 3 months at each station, the station T80max was a median of the 38th percentile of summer maximum temperature (range across stations: 20th to 93rd percentile) and a median of the 79th percentile of temperature across all summer hours (range: 33rd to 99th). Thus, while there is variation in the mapping between percentiles of all-year daily maximum temperature and percentiles of summer temperature that relates to temperature seasonality and diurnal range, temperatures at or above T80max are typically found in about 60% of summer days as the daily maximum and in about 20% of all summer hours, supporting its description as a typical summer temperature as contrasted with TXx, the annual maximum."
Additionally, results are now presented (in the new Figure 3) for continental warming across different Tmax percentiles, enabling readers to get a sense of how much the results would change if one was to consider a different Tmax percentile as the reference.
> The analysis of only TXX compared to Tmax80 is not sufficient to study amplification of extreme temperatures. There should be more climate extreme indices to be investigated such as 95th or 99th percentiles of maximum temperatures. (Please look at ETCDDI indices)
As explained under Methods, TXx was considered more suitable for the current analysis because it is more extreme than alternatives such as the 95th and 99th percentiles, yet common enough for trends in it to be meaningfully calculated. This is consistent with the IPCC AR6, whose WG1 chapter on Weather and Climate Extreme Events in a Changing Climate, cited in the Introduction, uses TXx as a primary indicator of extreme heat. Additionally, results are now presented for continental warming across different Tmax percentiles, including the 90th and 99th, enabling readers to get a sense of how much the results would change if one was to consider a different Tmax percentile as the extreme level (Figure 3).
> Line 88 please correct “intensification”.
Fixed.
> Figure1,2 and 3 Scale and colormap should be redefined. It is hard to understand the changes as it is. Europe and Africa are divided into two pieces in the map, and it is difficult to interpret. I suggest dividing the map by 200th longitude if possible. And country borders could be nice to be added for a better representation.
For the panels showing temperature changes, I changed the colormap to a blue-red one, similar to what NOAA uses. The axis and legend numbers have been enlarged to be more readable. The dividing line was moved so that Europe and Africa are united. Adding country borders is possible, but I'm worried that it would overly clutter the maps, and it also isn't very common in maps generated in global climate studies, so I left them out for now.
> Line 122 1970-2020 or 1959-2021? Please correct it.
Fixed.
> Interpretation of results should be given in details and in terms of regions.
Since this is a global study, the level of detail to which each region can be discussed is limited, but I expanded the discussion somewhat to highlight more of the regional impacts and their possible causes.
> Line 139 a is missing in “irrigtion”.
Line 188 owas should be deleted.
Fixed.
> Conclusion is weak and should be improved.
The conclusion has been revisited and expanded.
Reviewer 3 Report
I only found some minor errors but missed an explanation of how you exactly calculated the population-weighted averages.
Typos:
line 88: intensfication
line 125: Sacnadanvia
line 188 : owas
Author Response
> I only found some minor errors but missed an explanation of how you exactly calculated the population-weighted averages.
The equation for calculating the averages was added under Methods.
> Typos:
line 88: intensfication
line 125: Sacnadanvia
line 188 : owas
Fixed.
Round 2
Reviewer 2 Report
The author revised the manuscript accordingly. I suggest accepting the manuscript in its present form.
