Abstract
Convection-permitting models (CPMs)—the newest generation of high-resolution climate models—have been shown to greatly improve the representation of subdaily and hourly precipitation, in particular for extreme rainfall. Intense precipitation events, however, often occur on subhourly timescales. The distribution of subhourly precipitation, extreme or otherwise, during a rain event can furthermore have important knock-on effects on hydrological processes. Little is known about how well CPMs represent precipitation at the subhourly timescale, compared to the hourly. Here we perform multi-decadal CPM simulations centred over Catalonia and, comparing with a high temporal-resolution gauge network, find that the CPM simulates subhourly precipitation at least as well as hourly precipitation is simulated. While the CPM inherits a dry bias found in its parent model, across a range of diagnostics and aggregation times (5, 15, 30 and 60 min) we find no consistent evidence that the CPM precipitation bias worsens with shortening temporal aggregation. We furthermore show that the CPM excels in its representation of subhourly extremes, extending previous findings at the hourly timescale. Our findings support the use of CPMs for modelling subhourly rainfall and add confidence to CPM-based climate projections of future changes in subhourly precipitation, particularly for extremes.
Highlights
Short-duration, high-intensity precipitation events are a leading cause of flash flooding, posing health and economic risks to society
While the Convection-permitting models (CPMs) inherits a dry bias found in its parent model, across a range of diagnostics and aggregation times (5, 15, 30 and 60 min) we find no consistent evidence that the CPM precipitation bias worsens with shortening temporal aggregation
COSMO regional model in climate mode (CCLM)-02 temperatures are first aggregated to the Spain02 grid. 0.95, 0.99 and 0.999 quantiles are computed for each temperature bin, as long as at least 20, 100, or 1000 data points are present, respectively, avoiding erroneous artefacts associated with inadequate sample size [55]
Summary
Short-duration, high-intensity precipitation events are a leading cause of flash flooding, posing health and economic risks to society Realistic modelling of such events is important in both weather forecasting and climate projections. Such heavy precipitation events typically, though not always, result from atmospheric convection and are in Europe most common in summer or autumn, dependent on regional factors [1]. The use of ‘convection-permitting models’ (CPMs)—that is, high-resolution atmospheric models (grid spacing
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