Which weather systems are projected to cause future changes in mean and extreme precipitation in CMIP5 simulations?

Abstract

Future changes in precipitation due to climate change are of great concern to society. However, questions such as “Which weather systems will cause which changes?” and “Is the relative importance of these weather systems likely to change in the future?” have not been addressed fully yet. Here we present the first global estimates of the relative contributions of different weather systems (i.e., tropical cyclones, extratropical cyclones including fronts, and others) to changes in annual mean and extreme precipitation in the late 21st century using multimodel projections of the Coupled Model Intercomparison Project Phase 5. Although the models present biases in tropical cyclones over southern hemisphere, in particular, the representations of global weather system patterns are comparable to the reanalysis data. Total precipitation from tropical cyclones decreases (increases) in the tropics (subtropics) and that from extratropical cyclones including fronts decreases (increases) on the equatorial (poleward) side of the storm tracks. In addition, the mean intensity and frequency of system‐wise precipitation can change significantly even without considerable changes in annual amounts. We found that the subtropics, particularly in the Pacific and North Atlantic, are the regions where the proportions of precipitation by weather systems in annual mean and extreme precipitation display notable changes, suggesting distinct shifts in climate regimes. These regions have a common feature: they undergo the influence of several distinct weather systems in the present climate. In regions where climate regime shifts are projected, even the weather systems that have a minor contribution to precipitation in the present climate may cause considerable changes in annual and extreme precipitation.

Relative contributions of weather systems to mean and extreme global precipitation

“…Utsumi et al . [] suggested to use the 850 hPa temperature as a thermal variable instead of the 900 hPa wet‐bulb potential temperature suggested by Hewson []. The 850 hPa temperature was used to focus on those fronts with strong baroclinic characteristics that are usually associated with ExC centers.…”

“…ExC centers and fronts were detected based on the method by Utsumi et al . [] from the JRA25 regridded to 1.0° spatial resolution. The objective detection method for ExC centers of Utsumi et al .…”

“…[2016] from the JRA25 regridded to 1.0°spatial resolution. The objective detection method for ExC centers of Utsumi et al [2016] is similar to that of Geng and Sugi [2001] which considers the local minima of SLP field and pressure gradients. The major difference from the method of Geng and Sugi [2001] is that TC centers are explicitly excluded from ExC center candidates.…”

“…To detect the Journal of Geophysical Research: Atmospheres 10.1002/2016JD025222 fronts associated with extratropical cyclones, horizontal gradients of a thermal variable were referred. Utsumi et al [2016] suggested to use the 850 hPa temperature as a thermal variable instead of the 900 hPa wet-bulb potential temperature suggested by Hewson [1998]. The 850 hPa temperature was used to focus on those fronts with strong baroclinic characteristics that are usually associated with ExC centers.…”

Physical Responses of Convective Heavy Rainfall to Future Warming Condition: Case Study of the Hiroshima Event

“…However, there is a possibility that extreme precipitation derived from other types of meteorological phenomena does not increase so much, i.e., under the C-C relation, or even decreases due to the different physical response to the future atmospheric warming from that of tropical cyclones. Although Utsumi et al (2016) examined the future changes in three types of meteorological phenomena (tropical cyclones, extratropical cyclones including fronts, and others), their analyses were performed from the global point of view, and thus the rainfall events that are smaller-scale but intense enough to cause disasters have not been fully investigated.…”