No abstract

The Atlantic hurricane season and the European windstorm season are found to be negatively correlated in a seasonal forecast model. The probability of extremes occurring in both seasons is compared to the probability of extremes in each season being independent of one another. An above average Atlantic hurricane season is followed by an above average European windstorm season less often than if they were independent, consistent across three intensity measures. The El Niño-Southern Oscillation is found to be in the positive (negative) phase when hurricane activity is suppressed (enhanced) and European windstorm activity is enhanced (suppressed). A clear extratropical response in the seasonal forecast model to El Niño/La Niña provides a probable pathway for the observed correlation between the extreme event seasons. This result has important predictability implications for both the actuarial and seasonal forecasting communities. Plain Language Summary On both sides of the Atlantic Ocean storms with extremely high wind speeds are a natural hazard, resulting in billions of dollars in damages and loss of life. During the late summer and autumn, hurricanes which form in the tropical ocean impact the Caribbean and United States. In the winter, windstorms form in the midlatitude regions primarily impacting Europe. These two seasons are traditionally considered to be unrelated. Here we present evidence that the two are linked through the climate system, specifically the El Niño-Southern Oscillation. An active Atlantic tropical cyclone season precedes an active European windstorm season less often than if the two seasons were independent. Future efforts to predict how damaging the upcoming European windstorm season may be should take this into account, and the insurance industry should be aware that these two risks are not independent. Both European windstorm and Atlantic TC frequency is influenced by the El Niño-Southern Oscillation (ENSO). ENSO modulates the favorability of Atlantic TC development conditions through suppressed (La Niña) or enhanced (El Niño) wind shear in the tropical Atlantic (

The complex dynamic climate system often exhibits hierarchical modularity of its organization and function. Scientists have spent decades trying to discover and understand the driving mechanisms behind western African Sahel summer rainfall variability, mostly via hypothesis-driven and/or firstprinciples based research. Their work has furthered theory regarding the connections between various climate patterns, but the key relationships are still not fully understood. We present Coupled Heterogeneous Association Rule Mining (CHARM), a computationally efficient methodology that mines higher-order relationships between these subsystems' anomalous temporal phases with respect to their effect on the system's response. We apply this to climate science data, aiming to infer putative pathways/cascades of modulating events and the modulating signs that collectively define the network of pathways for the rainfall anomaly in the Sahel. Experimental results are consistent with fundamental theories of phenomena in climate science, especially physical processes that best describe sub-regional climate.

No abstract

The Atlantic hurricane season and the European windstorm season are found to be negatively correlated in a seasonal forecast model. The probability of extremes occurring in both seasons is compared to the probability of extremes in each season being independent of one another. An above average Atlantic hurricane season is followed by an above average European windstorm season less often than if they were independent, consistent across three intensity measures. The El Niño-Southern Oscillation is found to be in the positive (negative) phase when hurricane activity is suppressed (enhanced) and European windstorm activity is enhanced (suppressed). A clear extratropical response in the seasonal forecast model to El Niño/La Niña provides a probable pathway for the observed correlation between the extreme event seasons. This result has important predictability implications for both the actuarial and seasonal forecasting communities.Plain Language Summary On both sides of the Atlantic Ocean storms with extremely high wind speeds are a natural hazard, resulting in billions of dollars in damages and loss of life. During the late summer and autumn, hurricanes which form in the tropical ocean impact the Caribbean and United States. In the winter, windstorms form in the midlatitude regions primarily impacting Europe. These two seasons are traditionally considered to be unrelated. Here we present evidence that the two are linked through the climate system, specifically the El Niño-Southern Oscillation. An active Atlantic tropical cyclone season precedes an active European windstorm season less often than if the two seasons were independent. Future efforts to predict how damaging the upcoming European windstorm season may be should take this into account, and the insurance industry should be aware that these two risks are not independent.Both European windstorm and Atlantic TC frequency is influenced by the El Niño-Southern Oscillation (ENSO). ENSO modulates the favorability of Atlantic TC development conditions through suppressed (La Niña) or enhanced (El Niño) wind shear in the tropical Atlantic (