Increase in Subdaily Precipitation Extremes in India Under 1.5 and 2.0 °C Warming Worlds

• Published in: Geophysical research letters Vol. 45; no. 14; pp. 6972 - 6982
• Main Authors: Ali, Haider, Mishra, Vimal
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28-07-2018
• Subjects: Duration; extreme events; Extreme weather; Flood frequency; Flooding; General circulation models; Global temperatures; Hourly; Mean temperatures; nonstationary; Paris Agreement; Precipitation; Scaling; stationary; storm water designs; Storms; Stormwater; Temperature; Temperature effects; urban; Urban areas; India
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2018GL078689

An increase in short duration precipitation extremes poses challenges for storm water design in rapidly urbanizing India. The recent Paris Agreement aims to limit the global mean temperature (GMT) below 1.5 °C (and possibly below 2.0 °C) from the preindustrial level. However, the changes in subdaily precipitation extremes in India remain unrecognized under the 1.5‐ and 2.0‐°C temperature targets. Here using observations and projections of the subdaily precipitation, we show that a majority (11 out of 15) of General Circulation Models underestimate 3‐hourly precipitation extremes and overestimate the relationship between 3‐hourly precipitation extremes and GMT (scaling) in India. A rise of 1.5 (2.0 °C) in GMT from the preindustrial level is projected to cause 20% (25%) increase in 3‐hourly precipitation maxima at 100‐year return period under the stationary condition, which can further rise by 10% under the nonstationary condition. Projected warming results in a much faster (almost twice) increase in 3‐hourly precipitation maxima than 24‐hourly 100‐year precipitation maxima. Moreover, 3‐hourly 100‐year precipitation maxima are projected to increase significantly at 78 locations (out of 89) if GMT increases from 1.5 to 2.0 °C from the preindustrial level. Our findings have implications for urban storm water designs in India.
Plain Language Summary
Urban areas in India face frequent flooding due to increase in short‐duration precipitation extremes. However, it remains unknown how short‐duration precipitation extremes that are relevant to urban storm water designs change under the 1.5° and 2.0° warming worlds. Here using the data from CMIP5 GCMs and observations, we show that 3‐hourly precipitation maxima at 100‐year return interval are projected to increase by 20% (25%) if the global mean temperature rises above 1.5° (2.0°) from the preindustrial level. Under the nonstationary assumption, short duration precipitation extremes are projected to rise more than that of under stationary assumption. Our findings provide new insights for urban storm water designs in India.
Key Points
A majority of General Circulation Models underestimate 3‐hourly precipitation extremes in India
The 3‐hourly precipitation maxima at 100‐year return period are projected to increase by 20% and 30%, assuming stationary and nonstationary conditions under the 1.5 degrees Celsius warming world
The 3‐hourly 100‐year precipitation maxima are projected to increase faster (almost twice) than 24‐hourly precipitation maxima under climate warming