Non-Parametric and Robust Sensitivity Analysis of the Weather Research and Forecast (WRF) Model in the Tropical Andes Region

• Published in: Atmosphere 2023-04, Vol.14 (4), p.686
• Main Authors: Hinestroza-Ramirez, Jhon E., Rengifo-Castro, Juan David, Quintero, Olga Lucia, Yarce Botero, Andrés, Rendon-Perez, Angela Maria
• Format: Article
• Language: English
• Subjects: Air pollution; Chemical transport; Climate and weather; Data assimilation; Decision making; Distribution; ensemble approach; Environmental aspects; Environmental health; Errors; Estimates; initial condition perturbation; Initial conditions; Modelling; non-parametric statistic; Nonparametric statistics; Normal distribution; Ordinary differential equations; Ozone; Parameter sensitivity; Physics; Probability distribution functions; Radiation; Rank tests; Robustness; Sensitivity analysis; Simulation; Smog; Statistical analysis; Statistical methods; Topography; Urban heat islands; Variables; Weather; Weather forecasting
• ISSN: 2073-4433; 2073-4433
• DOI: 10.3390/atmos14040686

With the aim of understanding the impact of air pollution on human health and ecosystems in the tropical Andes region (TAR), we aim to couple the Weather Research and Forecasting Model (WRF) with the chemical transport models (CTM) Long-Term Ozone Simulation and European Operational Smog (LOTOS–EUROS), at high and regional resolutions, with and without assimilation. The factors set for WRF, are based on the optimized estimates of climate and weather in cities and urban heat islands in the TAR region. It is well known in the weather research and forecasting field, that the uncertainty of non-linear models is a major issue, thus making a sensitivity analysis essential. Consequently, this paper seeks to quantify the performance of the WRF model in the presence of disturbances to the initial conditions (IC), for an arbitrary set of state-space variables (pressure and temperature), simulating a disruption in the inputs of the model. To this aim, we considered three distributions over the error term: a normal standard distribution, a normal distribution, and an exponential distribution. We analyze the sensitivity of the outputs of the WRF model by employing non-parametric and robust statistical techniques, such as kernel distribution estimates, rank tests, and bootstrap. The results show that the WRF model is sensitive in time, space, and vertical levels to changes in the IC. Finally, we demonstrate that the error distribution of the output differs from the error distribution induced over the input data, especially for Gaussian distributions.