Abstract
One of the unresolved and debated topics in climatic and atmospheric
sciences is whether soil moisture (SM) anomalies can trigger extreme
precipitation (P) events? Researchers have used coupled atmospheric
model experiments, models based on simple water budget equations, and
water vapour tracing studies; however, a consensus is lacking. Some
studies reported that the excess SM anomalies trigger subsequent P; a
few also postulate about a negative feedback loop. In the present study,
we used a novel Event Coincidence Analysis to investigate this trigger
relationship between SM and P. Using SM and P data from 2004-2020, we
identified hotspots of SM-P coupling over India. A statistical
significance test (α = 0.10) was carried out to ensure that the observed
coincidences are not by chance. On increasing, the temporal window from
one day to three-day the extent and severity of the hotspots increased
significantly. The highest values of trigger coincidence rates are
observed over central India (>70%). Our observed results
agree with the widely regarded hypothesis of stronger SM-P coupling in
transitional regions between wet and dry climates. The results obtained
in our work has vast potential for atmospheric forecast purposes,
including flood early warning systems for India.