Projections of sub-daily precipitation extremes in major global urban areas

Abstract:

Extreme precipitation events cause disproportionate damage to wealth and infrastructure. Precipitation extremes lead to flooding in urban areas and disrupt transportation. We evaluated CMIP5 global climate models against sub-daily observations of extreme precipitation events from the TRMM for major urban areas in the world. The evaluation was performed for annual maximum precipitation for 3-24 hours durations. Moreover, after the evaluation of CMIP5 GCMs, we analyzed data from them to estimate changes in precipitation maxima under the projected future climate in major urban areas. Results suggest that the majority of CMIP5 GCMs underestimate 3-hourly precipitation maxima at most of the urban areas. However, negative bias in precipitation maxima in climate models improves with the duration of precipitation. Precipitation maxima are projected to increase significantly at majority of urban areas under the RCP 4.5 and 8.5 scenarios in future. Results underscore a need to further improve GCMs so that they can capture extreme precipitation intensity in urban areas. Moreover, projected increase in precipitation extremes may pose substantial challenges for urban infrastructure.