Karkınlı (2025) Multi-scale remote sensing of desertification trends and climate–vegetation interactions in the Konya basin, Türkiye (2000–2025)

Identification

• Journal: Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi
• Year: 2025
• Date: 2025-10-15
• Authors: Ahmet Emin Karkınlı
• DOI: 10.28948/ngumuh.1791557

Research Groups

Niğde Ömer Halisdemir University, Geomatics Engineering Department, Niğde, Türkiye

Short Summary

This study investigates desertification trends and climate-vegetation interactions in the Konya Basin, Türkiye, from 2000 to 2025, revealing a "greening-degradation paradox" where subtle basin-wide greening coexists with significant localized degradation hotspots driven by intensive agricultural practices and warming temperatures.

Objective

• To quantify long-term spatial–temporal trends in vegetation health using MODIS-derived Normalized Difference Vegetation Index (NDVI) and Soil-Adjusted Vegetation Index (SAVI).
• To analyze the relationships between vegetation indices and climatic variables (precipitation and temperature).
• To identify medium-resolution (30 m) degradation hotspots using Landsat data and evaluate their distribution across different land cover types.

Study Configuration

• Spatial Scale: Konya Closed Basin, Türkiye, covering approximately 50,000 km². Analyses were conducted at multiple resolutions: 250 m (MODIS), 500 m (MODIS), 30 m (Landsat, SRTM), 10 m (land cover), ~5.5 km (precipitation), and ~11 km (temperature).
• Temporal Scale: 2000–2025 for long-term trends and climate correlations; 2013–2025 for medium-resolution degradation hotspot analysis. Data were processed for the primary growing season (April–September).

Methodology and Data

• Models used: Google Earth Engine (GEE) platform for data acquisition and processing, pixel-wise linear regression for trend analysis, Pearson's correlation for climate-vegetation relationships, and a data-driven threshold (10th percentile of negative change values) for hotspot identification.
• Data sources:
  • Vegetation Indices: MODIS Terra/Aqua 16-Day L3 Global 250m product (MOD13Q1) for NDVI; MODIS 8-Day L3 Global 500m Surface Reflectance product (MOD09A1) for SAVI.
  • Medium-Resolution Vegetation: Landsat 8/9 Level 2, Collection 2, Tier 1 data (30 m resolution).
  • Precipitation: Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) daily dataset (0.05° / ~5.5 km resolution).
  • Temperature: ERA5-Land daily aggregated dataset (0.1° / ~11 km resolution) for mean 2-meter air temperature.
  • Land Cover: 2020 ESA WorldCover 10m land cover map.
  • Elevation: 30m SRTM Digital Elevation Model.

Main Results

• The Konya Basin exhibited a subtle basin-wide greening trend in NDVI and SAVI from 2000 to 2025, with croplands showing the most pronounced positive trend of approximately +0.0042 NDVI units per year.
• A statistically significant warming trend of 0.05 °C per year (p = 0.0102) was detected in mean growing-season temperature. Total growing-season precipitation showed high inter-annual variability but no clear long-term trend.
• Vegetation (NDVI) correlated positively and significantly with precipitation (r = 0.5017, p = 0.009) at the basin scale, but showed a weak and non-significant correlation with temperature (r = 0.0902, p = 0.6611).
• Spatial analysis revealed strong positive NDVI–precipitation correlations in northern rainfed grasslands and localized negative NDVI–temperature associations in irrigated southern plains.
• Medium-resolution Landsat data identified 3471.93 km² of significant degradation hotspots between 2013 and 2025. Of these, 21.4% (741.52 km²) were in croplands, and approximately 70% were concentrated below 1000 m elevation, where groundwater-dependent irrigation is most intense.

Contributions

• This research provides a comprehensive, multi-scale analysis of vegetation dynamics in the Konya Basin, integrating macro-scale (MODIS) and micro-scale (Landsat) data to overcome limitations of single-scale assessments.
• It clearly demonstrates the "greening–degradation paradox" in a semi-arid agro-ecosystem, showing that modest basin-wide greening can mask acute local degradation, particularly in intensively irrigated agricultural zones.
• The study offers a novel perspective on desertification drivers by disentangling climatic variability from human-induced degradation, providing robust evidence for targeted land and water management policies.

Funding

Not specified in the paper.

Citation

@article{Karkınlı2025Multiscale,
  author = {Karkınlı, Ahmet Emin},
  title = {Multi-scale remote sensing of desertification trends and climate–vegetation interactions in the Konya basin, Türkiye (2000–2025)},
  journal = {Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi},
  year = {2025},
  doi = {10.28948/ngumuh.1791557},
  url = {https://doi.org/10.28948/ngumuh.1791557}
}