1. Toward a Regional-Scale Seasonal Climate Prediction System over Central Italy Based on Dynamical Downscaling
- Author
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Rossella Ferretti, Lorenzo Sangelantoni, and Gianluca Redaelli
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Anomaly (natural sciences) ,0208 environmental biotechnology ,Probabilistic logic ,02 engineering and technology ,Prediction system ,ensemble seasonal forecasting ,Spatial distribution ,01 natural sciences ,dynamical downscaling ,020801 environmental engineering ,Climatology ,Dynamical downscaling ,Ensemble seasonal forecasting ,Regional climate modeling ,Environmental science ,Climate model ,lcsh:Q ,Precipitation ,Scale (map) ,regional climate modeling ,lcsh:Science ,0105 earth and related environmental sciences ,Downscaling - Abstract
Anticipating seasonal climate anomalies is essential for defining short-term adaptation measures. To be actionable, many stakeholders require seasonal forecasts at the regional scale to be properly coupled to region-specific vulnerabilities. In this study, we present and preliminarily evaluate a regional-scale Seasonal Forecast System (SFS) over Central Italy. This system relies on a double dynamical downscaling performed through the Regional-scale Climate Model (RCM) RegCM4.1. A twelve-member ensemble of the NCEP-CFSv2 provides driving fields for the RegCM. In the first step, the RegCM dynamically downscales NCEP-CFSv2 predictions from a resolution of 100 to 60 km over Europe (RegCM-d1). This first downscaling drives a second downscaling over Central Italy at 12 km (RegCM-d2). To investigate the added value of the downscaled forecasts compared to the driving NCEP-CFSv2, we evaluate the driving CFS, and the two downscaled SFSs over the same (inner) domain. Evaluation involves winter temperatures and precipitations over a climatological period (1982&ndash, 2003). Evaluation for mean bias, statistical distribution, inter-annual anomaly variability, and hit-rate of anomalous seasons are shown and discussed. Results highlight temperature physical values reproduction benefiting from the downscaling. Downscaled inter-annual variability and probabilistic metrics show improvement mainly at forecast lead-time 1. Downscaled precipitation shows an improved spatial distribution with an undegraded but not improved seasonal forecast quality.
- Published
- 2019