High-Resolution Gridded Climate Data for Djebel Aïssa NP (SW Algeria) Derived via Downscaling of WorldClim v2.1 Using GAM and RF

This dataset provides high-resolution climatic data for Djebel Aïssa National Park, located in southwestern Algeria. It was produced by downscaling WorldClim version 2.1 data (1 km resolution) using a hybrid statistical approach that combines Generalised Additive Models (GAM) and Random Forests (RF) to enhance spatial resolution. The downscaling process integrates local topographic variables derived from the ALOS PALSAR Digital Elevation Model (12.5 m resolution) to improve the accuracy of precipitation estimates across complex terrain. To further improve reliability, bias correction was applied. Precipitation data were corrected using quantile mapping based on a gamma distribution, with reference values extrapolated from a lapse rate gradient to better capture altitudinal variability. Temperature data were corrected using a non-parametric quantile mapping approach, aligning the empirical distributions of modelled and extrapolated values. These corrections reduce systematic biases and improve consistency with observed local climate conditions, thereby enhancing the dataset’s suitability for fine-scale ecological, hydrological, and climate impact studies. All R scripts used to generate and process these data are provided in an accompanying R Markdown (.Rmd) file and compiled PDF report, ensuring full transparency and reproducibility of the workflow. Dataset details: Geographic coverage: Djebel Aissa National Park, SW-Algeria Data source: Downscaled WorldClim Version 2.1 Temporal resolution: 1970-2000. Spatial resolution: 12.5 m spatial resolution. Coordinate reference system: WGS 84 (EPSG: 4326) Format: GeoTIFF (.tif) files Usage: This data can be used for climatic modeling, ecological studies, and environmental monitoring, particularly for studies related to vegetation dynamics, hydrology, and climate change impacts within Djebel Aissa National Park. Precipitation Variables Monthly Precipitation Format: 12 rasters (.tif) Unit: millimetres (mm) Description: Total precipitation per month. Annual Precipitation Format: Single raster Calculation: Sum of all 12 monthly precipitation rasters. Temperature Variables Monthly Minimum Temperature (Tmin) Format: 12 rasters (tif) Unit: Degrees Celsius (°C) Description: Minimum temperature for each month. Monthly Maximum Temperature (Tmax) Format: 12 raster (tif) Unit: Degrees Celsius (°C) Description: Maximum temperature for each month. Monthly Average Temperature (Tavg) Format: 12 raster (tif) Calculation: (Tmax+Tmin)/2 Description: Average monthly temperature. Annual Mean Temperature Format: Single raster (tif) Calculation: Mean of monthly average temperatures