the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 07 Apr 2025
CLIMADAT-GRid: A high-resolution daily gridded precipitation and temperature dataset for Greece
Abstract. We introduce the development of CLIMADAT-GRid, the first publicly available daily air temperature and precipitation gridded climate dataset for Greece at a high resolution of 1 km x 1 km, covering the period 1981–2019. The dataset is derived from quality-controlled and homogenized daily measurements from an extensive network of meteorological stations: 122 for temperature and 312 for precipitation. Several approaches are evaluated for generating the daily gridded datasets, and their accuracy is assessed against withheld observational data. To address the lack of observations in high-elevation areas, high-resolution simulations from the WRF model are blended with the observational data to provide the gridded temperature data. CLIMADAT-GRid is benchmarked against the CHELSA-W5E5, a global climate product with a similar resolution, for the overlapping period 1981–2016. While both datasets show comparable results for temperature, CLIMADAT-GRid demonstrates superior spatial variability and closer agreement with observational data for both the mean and for the extreme values. Regarding precipitation, CLIMADAT-GRid consistency indicates higher values than CHELSA, especially during the rainy season, but exhibits better agreement with observations. In terms of the number of wet days, both datasets overestimate spatial means relative to observations, with CLIMADAT-GRid showing a more pronounced orographic pattern than CHELSA. Both datasets show similar results for the number of days with precipitation amounts equal to or higher than 10 mm, with CLIMADAT-GRid indicating better overall agreement with the observations. The CLIMADAT-GRid dataset is publicly available at https://doi.org/10.5281/zenodo.14637536 and can be cited as Varotsos et al. (2025).
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RC1: 'Comment on essd-2025-29', Anonymous Referee #1, 13 Apr 2025
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The manuscript presents observational gridded datasets over Greece, covering daily total precipitation and daily mean, maximum, and minimum temperatures. The authors have applied quality control and homogenization procedures to the input data. They also examined the use of different statistical methods for spatial interpolation. In addition, they incorporated numerical model output to address gaps in the observational network, which is relevant given the complex topography of the region. The datasets have been evaluated through cross-validation using independent observations and compared with existing gridded products available for the same area. The figures included in the paper are informative and clearly presented. The results support the conclusions drawn by the authors.
There are a few points that may require clarification or expansion. First, the manuscript does not include a sensitivity analysis regarding the use of WRF model output for a year other than 1999. While this analysis may not be essential, the authors could expand the discussion around lines 139–141. For example, they might consider whether a regional reanalysis product, such as CERRA, could have been used, or if WRF simulations were tested for other years. Second, certain methodological choices could be described in more detail. This is outlined in the comments below.
Overall recommendation: The study provides a useful dataset and analysis for the region. I recommend publication after the authors have addressed the comments that follow.
Comments:
1. Regarding the gridding of temperature data: It is likely that the station locations, your grid, and the CHELSA grid differ in elevation for the same geographic points. This is expected, but it is unclear how these differences were handled during the spatial analysis and subsequent comparisons. Did you interpolate all datasets onto a common grid before comparison? This point could be clarified in Sections 3.3 and 3.4. Also, discussing elevation differences may help with the interpretation of results in Section 4.2.1. Please consider revising that section accordingly.
2. The choice of FRK as the final spatial analysis method is only briefly mentioned in lines 289–291. This decision is important and could be stated earlier and more clearly. For example, it could be introduced in the abstract (e.g., after “against withheld observational data,” add a sentence about the method used). Additionally, you could move the relevant lines to the beginning of Section 4.1, rather than introducing FRK in the section discussing temperature results. Consider also whether the conclusion should briefly mention that FRK performed best among the methods evaluated. It may also be useful to explain why a single method (FRK) was chosen for both temperature and precipitation, despite indications that SVM performed well for precipitation. A short explanation of the reasoning behind this choice could be helpful.
3. Lines 42–44: The phrase “model-generated” could be clarified by adding that these were generated using statistical methods, to distinguish them from output from dynamical models.
4. Section 2.1: Please specify the definition of a “day” for each variable (e.g., whether it spans from 00 UTC to 24 UTC). Even if this follows a standard convention, it should be stated explicitly.
5. Line 165: Consider whether this line should be part of the previous paragraph, as the new line may not be necessary.
Citation: https://doi.org/10.5194/essd-2025-29-RC1
Data sets
CLIMADAT-GRid: A high-resolution (1 km x 1 km) daily gridded precipitation and temperature dataset for Greece Konstantinos V. Varotsos, Gianna Kitsara, Anna Karali, Ioannis Lemesios, Platon Patlakas, Maria Hatzaki, Vassilis Tenentes, George Katavoutas, Athanasios Sarantopoulos, Basil Psiloglou Aristeidis G. Koutroulis, Manolis G. Grillakis, and Christos Giannakopoulos https://doi.org/10.5281/zenodo.14637536
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