Quantitative contribution of ENSO to precipitation-temperature dependence and associated compound dry and hot events

Compound dry and hot events (CDHEs) are closely related to negative precipitation-temperature (P-T) dependence that is commonly observed during warm seasons over global land areas. The P-T dependence can be induced by El Nin similar to o-Southern Oscillation (ENSO) or other non-ENSO factors (e.g., local coupled feedbacks). However, the disentanglement of impacts from ENSO on the P-T dependence and associated CDHEs is not clear. By comparing the impacts during ENSO years and neutral years, we quantify the contribution of ENSO to the P-T dependence and likelihood of CDHEs during warm seasons over global land areas. For the regions with significant impacts of ENSO on CDHEs (e.g., southern North America, northern South America, northern and southern Africa, southern and southeastern Asia, and Australia), the mean P-T dependence (measured by Kendall's rank correlation) enhances from -0.16 for neutral years to -0.24 for ENSO years. Accordingly, El Nin similar to o (La Nin similar to a) could induce an increase of around 60% (a decrease of around 35%) in the likelihood of CDHEs in these regions. Results from this study could be useful for understanding driving factors of CDHEs over global land areas.

Automated summary

The study compared the impacts of ENSO years and neutral years on the precipitation-temperature dependence and likelihood of Compound dry and hot events (CDHEs) during the warm seasons over global land areas. It found that ENSO has a significant impact on CDHEs in regions such as southern North America, northern South America, northern and southern Africa, southern and southeastern Asia, and Australia.