Yılmaz (2025) From Past to Future: Uzbekistan’s Climate Signals Through Time

Identification

• Journal: ISPRS annals of the photogrammetry, remote sensing and spatial information sciences
• Year: 2025
• Date: 2025-11-12
• Authors: Volkan Yılmaz
• DOI: 10.5194/isprs-annals-x-5-w3-2025-57-2025

Research Groups

Department of Geomatics Engineering, Karadeniz Technical University, Trabzon, Türkiye

Short Summary

This study analyzed historical trends (1995-2024) and forecasted future trajectories (2025-2050) of key climate variables in Uzbekistan using multi-source satellite data and reanalysis. Results indicate a significant warming and drying trend, with projected increases in land surface temperature, evapotranspiration, and vegetation, alongside a possible decline in soil moisture.

Objective

• To investigate long-term trends (1995-2024) and forecast future trajectories (2025-2050) of evapotranspiration, land surface temperature (LST), normalized difference vegetation index (NDVI), soil moisture, and precipitation across Uzbekistan to inform climate impact assessment and water resource planning.

Study Configuration

• Spatial Scale: Uzbekistan (total area of 447,400 km²)
• Temporal Scale: Historical analysis: 1995–2024; Future projection: 2025–2050

Methodology and Data

• Models used: Mann-Kendall test (for trend analysis), Autoregressive Integrated Moving Average (ARIMA) model (for forecasting)
• Data sources:
  • Platform: Google Earth Engine (GEE)
  • Evapotranspiration: MODIS (MODIS/061/MOD16A2, MODIS/006/MOD16A2)
  • Land Surface Temperature (LST): Landsat 5 (LANDSAT/LT05/C02/T1L2), Landsat 8 (LANDSAT/LT08/C02/T1L2)
  • Normalized Difference Vegetation Index (NDVI): Landsat 5 TM, Landsat 8 (derived from surface reflectance imagery)
  • Soil Moisture: ERA5-Land reanalysis dataset (ECMWF/ERA5_LAND/HOURLY)
  • Precipitation: CHIRPS dataset (USCB-CHG/CHIRPS/DAILY)

Main Results

• Historical Trends (1995-2024) via Mann-Kendall Test:
  • Statistically significant increasing trends were observed for Land Surface Temperature (LST, p=0.0246), Normalized Difference Vegetation Index (NDVI, p=0.0017), and Evapotranspiration (p=0.0446).
  • Trends for Soil Moisture (decreasing, p=0.4118) and Precipitation (slightly increasing, p=0.6427) were not statistically significant.
• Future Projections (2025-2050) via ARIMA Model:
  • Evapotranspiration: Projected to increase from 180 mm/year to 265 mm/year (historical range 70-130 mm/year, with recent spikes to 218 mm/year).
  • Land Surface Temperature (LST): Projected to reach up to 43 °C by 2050, indicating a substantial warming trend.
  • Normalized Difference Vegetation Index (NDVI): Projected to reach up to 0.1 by 2050 (historical range 0.04-0.085), indicating a slight improvement but still critically low vegetative density.
  • Soil Moisture: Projected to decline further, potentially reaching as low as 0.12 m³/m³ by 2050 (historical range 0.11-0.18 m³/m³).
  • Precipitation: Projected to continue a slight upward trend, potentially reaching 220 mm/year by 2050 (historical mean ~180 mm/year).
• ARIMA Model Performance (R² on 70/30 training-test split): NDVI (0.64) showed the highest accuracy, followed by precipitation (0.54), LST (0.52), evapotranspiration (0.46), and soil moisture (0.44).
• Overall, the findings suggest a warming and drying climate scenario for Uzbekistan, necessitating proactive land and water management strategies.

Contributions

This study provides a comprehensive and integrated assessment of long-term historical trends (1995-2024) and future projections (2025-2050) of key climate variables in Uzbekistan using multi-source remote sensing and reanalysis data within the Google Earth Engine platform. It addresses a critical gap in understanding regional hydro-climatic dynamics, offering valuable insights for climate impact assessment, water resource planning, and regional adaptation strategies in an arid to semi-arid region highly vulnerable to climate change.

Funding

Not specified in the provided text.

Citation

@article{Yılmaz2025From,
  author = {Yılmaz, Volkan},
  title = {From Past to Future: Uzbekistan’s Climate Signals Through Time},
  journal = {ISPRS annals of the photogrammetry, remote sensing and spatial information sciences},
  year = {2025},
  doi = {10.5194/isprs-annals-x-5-w3-2025-57-2025},
  url = {https://doi.org/10.5194/isprs-annals-x-5-w3-2025-57-2025}
}