Finding optimal Noah-MP parameterizations for the characterization of surface heat fluxes in the Iberian Peninsula

TL;DR

This study optimizes Noah-MP land surface model parameters to accurately simulate surface heat fluxes over the Iberian Peninsula, enhancing land-atmosphere interaction understanding in regional climate models.

Contribution

It identifies optimal Noah-MP parameter combinations for the Iberian Peninsula, improving heat flux simulation accuracy in WRF regional climate modeling.

Findings

WRF/Noah-MP reproduces soil moisture and heat fluxes well, especially in wetter conditions.

An optimal parameter configuration (s27I) significantly improves heat flux characterization.

Parameter choices like canopy resistance and soil moisture factors greatly impact model performance.

Abstract

Land surface models (LSMs) play a crucial role in characterizing land-atmosphere interactions by providing boundary conditions to regional climate models (RCMs). This is particularly true over the Iberian Peninsula (IP), where a water-limited regime governs much of the territory. We optimize the configuration of the Noah land surface model with multiparameterization options (Noah-MP) for characterizing heat fluxes in the IP when the Weather Research and Forecasting (WRF) model v3.9.1 is used as an RCM. We perform 70 one-year simulations using 35 Noah-MP combinations, for a dry year (2005) and a wet year (2010). Land-surface heat fluxes and soil moisture from WRF/Noah-MP are evaluated against FLUXNET station data and the CERRA-Land reanalysis. In general, WRF/Noah-MP reproduces soil moisture and surface heat fluxes well over the IP, especially under wetter conditions. Clustering identifies an optimal configuration from 10 groups (A to J). The Noah-MP options with greatest impact are canopy stomatal resistance (CRS), surface exchange coefficient for heat (SFC), soil-moisture factor controlling stomatal resistance (BTR), runoff and groundwater (RUN), and surface resistance to evaporation/sublimation (RSF); dynamic vegetation (DVEG) also matters. Several configurations performed reasonably; experiment s27I (Jarvis CRS, Chen97 SFC, CLM-type BTR, BATS RUN, and adjusted Sellers RSF for wet soils) provides a particularly good characterization of heat fluxes over the IP.