Singh et al. (2025) Mount Pinatubo's effect on the moisture-based drivers of plant productivity

Identification

• Journal: Atmospheric chemistry and physics
• Year: 2025
• Date: 2025-11-24
• Authors: Ram Singh, Kostas Tsigaridis, Diana Bull, Laura Swiler, Benjamin Wagman, Kate Marvel
• DOI: 10.5194/acp-25-16511-2025

Research Groups

• Center for Climate Systems Research, Columbia University
• NASA Goddard Institute for Space Studies
• Sandia National Laboratories

Short Summary

This study investigates the impact of the 1991 Mt. Pinatubo eruption on moisture-based drivers of plant productivity using an Earth system model. It finds that up to 10%–15% of land regions exhibit statistically significant hydroclimate responses (wet/dry) as measured by Soil Moisture Deficit Index (SMDI) and Evapotranspiration Deficit Index (ETDI), providing a more robust understanding of agricultural impacts than precipitation alone, with regional variations in the dominant limiting factors.

Objective

• To explore the understudied store (soil moisture) and flux (evapotranspiration) of water as short-term ecohydrological controls over plant productivity in response to the 1991 eruption of Mt. Pinatubo.
• To investigate the mechanisms by which the Mt. Pinatubo eruption affected hydroclimatic conditions and water-based drivers of plant productivity.
• To explicitly investigate changes in agricultural drought indices from Mt. Pinatubo by considering soil moisture and evapotranspiration as potential short-term controls over productivity in particular regions.

Study Configuration

• Spatial Scale: Global, with regional analyses focusing on equatorial Africa, the Middle East (eastern Mediterranean/western Asia), and Northern Asia. Atmospheric model resolution is 2.0° × 2.5° latitude-longitude, and the ocean model resolution is 1° × 1.25°.
• Temporal Scale: Analysis period from 1991 to 1995 (post-eruption), with a reference/calibration period of 1950–2014 for climatology and drought indices. Simulations cover 1850–1999, with weekly and seasonal temporal resolutions for impact metrics.

Methodology and Data

• Models used: NASA GISS ModelE2.1 (MATRIX) Earth system model.
  • Atmospheric component: 2.0° × 2.5° latitude-longitude grid, 40 vertical levels, model top at 0.1 hPa.
  • Aerosol microphysics: MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) module.
  • Ocean component: GISS Ocean v1, 1° × 1.25° horizontal resolution, 40 vertical layers.
  • Land component: Ent Terrestrial Biosphere Model (TBM) with interactive carbon cycle, satellite-derived plant functional types, and prescribed crop calendar.
• Data sources:
  • Volcanic SO2 forcing: VolcanEESM (1850–1977) and satellite measurement-based SO2 inventory (Carn et al., 2016) for 1978–2021.
  • Anthropogenic emissions: Community Emission Data System (CEDS) inventory.
  • Biomass burning: van Marle et al. (2017) for pre-1997 and GFED4s inventory (van der Werf et al., 2017) for 1997 onwards.
  • Plant functional type: MODIS (Moderate Resolution Imaging Spectroradiometer).
  • Irrigation water demand: Wisser et al. (2010) and Wada et al. (2013).
  • Drought indices: Soil Moisture Deficit Index (SMDI) and Evapotranspiration Deficit Index (ETDI) calculated from model output at weekly and monthly scales.

Main Results

• The model simulated a global mean surface cooling of approximately 0.5 °C following the Mt. Pinatubo eruption.
• Rainfall response was spatially heterogeneous with large temporal variability, showing suppressed rainfall in the Northern Hemisphere.
• Up to 10%–15% of land regions showed a statistically significant hydroclimate response (wet and dry) as calculated by the Soil Moisture Deficit Index (SMDI) and Evapotranspiration Deficit Index (ETDI), providing a more robust understanding of plant productivity impacts.
• In equatorial Africa, seasonal decreases in both SMDI and ETDI indicated a likely negative impact on plant productivity due to moisture deficit.
• In the Middle East (eastern Mediterranean/western Asia), increases in both SMDI and ETDI indicated a positive effect on plant productivity, supported by increased rainfall and irrigation.
• In Northern Asia, an increase in SMDI was observed alongside a decrease in ETDI and plant transpiration, suggesting a reduction in plant productivity not primarily driven by water availability, but by temperature and radiation.
• Weekly scale analyses confirmed the seasonal inferences and demonstrated the utility of high-frequency data in explaining the effectiveness of short-term dry/wet conditions corresponding to regional crop cycles.
• The study conclusively demonstrated that in high-latitude regions (Northern Asia), plants were not utilizing available root-zone soil moisture, indicating that temperature and radiation were the primary controlling factors for reduced plant productivity.

Contributions

• This study is the first to comprehensively investigate multiple indicators of water use (soil moisture and evapotranspiration) in relation to agricultural productivity after a short-duration event like the Mt. Pinatubo eruption.
• It successfully demonstrated the potential of volcanically-induced hydroclimate responses using process-based compound drought indices (SMDI and ETDI), which provide a more robust assessment of impacts on plant productivity compared to traditional rainfall-centric approaches, addressing uncertainties in regional rainfall responses.
• The research provides critical insights into the temporal and latitudinal dependence of dominant hydroclimate drivers (moisture versus temperature/radiation) in shaping regional plant productivity responses.
• It conclusively showed that in high-latitude regions, despite sufficient soil moisture, plants do not utilize it for growth, indicating temperature and radiation as primary limiting factors, while water-based drivers predominantly influence productivity in tropical and subtropical regions.

Funding

• NASA High-End Computing (HEC) Program through the NASA Center for Climate Simulation (NCCS)
• Laboratory Directed Research and Development program at Sandia National Laboratories
• U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525
• Sandia National Laboratories (grant no. DE-NA0003525)

Citation

@article{Singh2025Mount,
  author = {Singh, Ram and Tsigaridis, Kostas and Bull, Diana and Swiler, Laura and Wagman, Benjamin and Marvel, Kate},
  title = {Mount Pinatubo's effect on the moisture-based drivers of plant productivity},
  journal = {Atmospheric chemistry and physics},
  year = {2025},
  doi = {10.5194/acp-25-16511-2025},
  url = {https://doi.org/10.5194/acp-25-16511-2025}
}