Work

Configuration dependence of atmospheric response to soil moisture perturbations in WRF simulations

Year: 2026

Type: preprint

Abstract: The representation of land–atmosphere coupling remains a major source of uncertainty in regional climate simulations, yet the effects of routine configuration choices on diagnosed coupling are rarely isolated. We use the Weather Research and Forecasting (WRF) model to investigate how model configuration influences land–atmosphere responses to soil moisture perturbations during the drought-affected 2022 warm season over the Carpathian Basin in Central Europe. Anomalously dry soil conditions were replaced with a wetter state representative of near-normal conditions (~35% increase over the central lowlands of the study region), while atmospheric forcing was unchanged between reference and adjusted simulations across configurations differing in horizontal resolution, convection representation, and spectral nudging. The thermodynamic response was similar across configurations, with near-surface cooling of 0.8–2.0 °C and dew-point temperature increases of 1.7–2.6 °C. In contrast, precipitation responses depended strongly on model configuration. Simulations with parameterized convection exhibited the largest precipitation increases, primarily through increased frequency, whereas simulations without cumulus parameterization produced smaller, more heterogeneous responses in frequency and intensity. A two-legged land–atmosphere coupling analysis showed a consistently positive spatial relationship between soil moisture and instability responses (r = 0.55–0.63), while the instability–precipitation relationship was weak and changed sign (r = −0.28 to 0.12). The precipitation response per unit increase in instability was similar between the freely evolving 10 km configurations but diverged under spectral nudging, increasing with parameterized convection and decreasing without cumulus parameterization. Because spectral nudging is widely applied in regional climate simulations, these results indicate that diagnosed land–atmosphere coupling depends not only on model physics but on the strategy used to constrain the large-scale circulation.

Source: Zenodo (CERN European Organization for Nuclear Research)

DOI: 10.5281/zenodo.19371405

Authors: Varga, Ákos János, Breuer, Hajnalka

Institutions: Eötvös Loránd University, Czech Academy of Sciences, Czech Academy of Sciences, Global Change Research Institute

Language: English

Topic: Meteorological Phenomena and Simulations

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: green

Funders: European Commission, Ministerstvo Školství, Mládeže a Tělovýchovy, Hungarian Scientific Research Fund