Precipitation characteristic changes due to global warming in a high-resolution (16 km) ECMWF simulation

Abstract

Changes in precipitation amount, intensity and frequency in response to global warming are examined using global high-resolution (16 km) climate model simulations based on the European Centre for Medium-range Weather Forecasts (ECMWF) Integrated Forecast System (IFS) conducted under Project Athena. Our study shows the increases of zonal-mean total precipitation in all latitudes except the northern subtropics (15 degrees-30 degrees N) and southern subtropics-to-midlatitudes (30 degrees-40 degrees S). The probability distribution function (PDF) changes in different latitudes suggest a higher occurrence of light precipitation (LP; 1 mm/day) and heavy precipitation (HP; 30 mm/day) at the expense of moderate precipitation reduction (MP; 1-30 mm/day) from Tropics to midlatitudes, but an increase in all categories of precipitation in polar regions. On the other hand, the PDF change with global warming in different precipitation climatological zones presents another image. For all regions and seasons examined, there is an HP increase at the cost of MP, but LP varies. The reduced MP in richer precipitation zones resides in the PDF peak intensities, which linearly increase with the precipitation climatology zones. In particular in the Tropics (20 degrees S to 20 degrees N), the precipitation PDF has a flatter distribution (i.e. HP and LP increases with MP reduction) except for the Sahara Desert. In the primary precipitation zones in the subtropics (20 degrees-40 degrees) of both hemispheres, precipitation over land switches toward higher intensity (HP increases, but MP and LP decrease) in both winter and summer, while precipitation over ocean in both seasons shows a flattening trend in the intensity distribution. For the major precipitation zones of the mid-to-high latitude belt (40 degrees-70 degrees), PDF of precipitation tends to be flatter over ocean in summer, but switches toward higher intensities over land in both summer and winter, as well as over ocean in winter.