Changes in Temperature-based Extremes Indices Due to Global Warming Projected by a Global 20-km-mesh Atmospheric Model

Abstract

Changes in temperature-based extremes over land due to global warming estimated by a global 20-km-mesh atmospheric model are analyzed using Frich’s five extremes indices. At the end of the 21^st Century, under the Intergovernmental Panel on Climate Change (IPCC) SRES A1B scenario, the model projects that the total number of frost days (Fd) decreases by more than 20 days per year and the length of the growing season (GSL) increases by about 14-34 days in northern mid- and high latitudes. The heat wave duration index (HWDI) and the percentage of time with a daily minimum temperature above the present-day 90^th percentile (Tn90) increase worldwide. The intra-annual extreme temperature range (ETR) decreases in northern high latitudes, east Asia, and eastern North America by 1.3-3.9°C, but it increases by 1.0°C in the Amazon. The high-resolution simulation reveals that changes in these indices are influenced by regional properties, such as the altitude and distance from the coast.