The mechanisms through which volcanic eruptions affect the El Niño-Southern Oscillation (ENSO) state are still controversial. Previous studies have invoked direct radiative forcing, an ocean dynamical thermostat (ODT) mechanism, and shifts of Intertropical Convergence Zone (ITCZ), among others, to explain ENSO response tropical eruptions. Here, these tested using ensemble simulations with Earth system model in aerosols from a Tambora-like eruption confined either Northern or Southern...

Abstract The response of El Niño–Southern Oscillation (ENSO) to mid‐Holocene boundary conditions remains an open question: paleoclimate proxies and climate model simulations do not agree in the magnitude reduction ENSO variability, while recent proxy evidence from fossil corals central Pacific show that variability compared end twentieth century is different during other Holocene time intervals. This inconsistent with interpretation lake ocean sediment records eastern Pacific, which a...

Abstract A large ensemble of Earth System Model simulations is analyzed to show that high‐latitude Northern Hemisphere eruptions give rise El Niño‐like anomalies in the winter following eruption, amplitude which depends on state tropical Pacific at time eruption. The are almost three times larger when eruption occurs during an incipient La Niña or a neutral compared Niño. differential response results from stronger atmosphere‐ocean coupling and extra‐tropical feedbacks Differences continue...

Abstract Understanding El Niño-Southern Oscillation (ENSO) response to past climate forcings is hindered by conflicting paleoclimate evidence. Records from the eastern Pacific show an intensification of ENSO variability early late Holocene, while records central highly variable throughout Holocene without obvious relation insolation forcing, which main driver during this interval. Here, we via model simulations that can be reconciled considering changes in relative frequency three preferred...

Abstract Atmospheric blocking events are persistent quasi‐stationary geopotential height anomalies that divert the jet stream from its climatological path in mid‐ to high‐latitudes. Previous studies have found different phases of El Niño–Southern Oscillation (ENSO) influence characteristics blocking, but none considered spatial diversity Niño. In this study, we examine Northern Hemisphere with respect “Central Pacific” (CP) and “Eastern (EP) flavors Niño 83 years ERA5 reanalysis. The two...

Abstract Humid heat extremes, characterized by high wet bulb temperature (Tw), pose significant health risks. While strong El Niño events are known to affect the frequency of extreme Tw days, distinct impacts Central Pacific (CP) and Eastern (EP) remain understudied. Using a 12‐member CMIP6 ensemble at discrete global warming targets (+1.5, 2, 3, 4°C), this study shows progressively enhanced humid extent during EP primarily in Mainland Southeast Asia, while South Asia experiences regionally...

Abstract Terrestrial proxies of wind direction spanning the last deglaciation suggest easterly winds were present near Laurentide Ice Sheet margin in North American midcontinent. However, existence and spatial extent such have not been investigated with transient paleoclimate model simulations, which could provide improved dynamical context for interpreting causes these winds. Here we assess near-surface retreating southern using iTRACE, a simulation deglacial climate from 20–11 ka. Near...

Abstract The equatorial cold tongue region has not warmed up in response to historical radiative forcing the real world, contrary strong warming often simulated by climate models. Here we demonstrate that models fail represent one or both of key processes driving observed sea surface temperature (SST) pattern formation: a realistic wind stress shaping subsurface cooling through wind‐driven circulation changes, and effective connectivity between temperatures via upwelling mixing....

Abstract Sediment records from Lake Pallcacocha, Ecuador, have been interpreted as proxies of El Niño–Southern Oscillation (ENSO) variability, owing to increased precipitation in the area during Niño events. However, lake's watershed receives processes arising both eastern and western Andes, where ENSO has different impacts; this led ambiguity observed regional signals consequently challenged suitability proxies. Here, a mesoscale weather prediction model is used investigate circulation...

The historical record of U.S. hurricane damage is analyzed using a peaks-over-threshold approach in which the generalized Pareto distribution (GPD) applied to model excesses above specified threshold for given metric. In addition absolute damages (total damage), this paper defines index as ratio base-year economic available value affected region. then incorporates physical covariates at individual level into GPD model, namely, maximum wind speed and simple yet novel measure mean bathymetric...

Abstract. Indonesia's climate is dominated by the equatorial monsoon system, and has been linked to El Niño-Southern Oscillation (ENSO) events that often result in extensive droughts floods over Indonesian archipelago. In this study we investigate ENSO-related signals a tree-ring δ18O record (1900–2007) of Javanese teak. Our results reveal clear influence Warm Pool (central Pacific) Niño on δ18O, no signal Cold Tongue (eastern events. These are consistent with distinct impacts two ENSO...

Abstract Zonal and meridional surface temperature gradients are considered to be determinants of large-scale atmospheric circulation patterns. However, there has been limited investigation these as diagnostic aids. Here, the twentieth-century variability in Northern Hemisphere equator-to-pole gradient (EPG) ocean–land contrast (OLC) is explored. A secular trend decreasing EPG OLC noted. Decadal interannual (ENSO-related) variations joint distribution identified, hinting at multistable...

Abstract The large-scale atmospheric circulation of the North Pacific associated with two types El Niño—the eastern (EP) and central (CP)—is studied in relation to Hawaiian winter (December–February) rainfall temperature. equatorial undergo active convective heating during EP Niño winters. local Hadley is enhanced an upper-level westerly jet stream elongated eastward. Due impact both phenomena, stronger anomalous descending motion, moisture flux divergence anomalies near Hawaii, reduction...

<p>The mechanisms through which volcanic eruptions impact the El Niño-Southern Oscillation (ENSO) state are still controversial. Previous studies have invoked direct radiative forcing, an ocean dynamical thermostat (ODT) mechanism and shifts of Intertropical Convergence Zone (ITCZ), among others, to explain ENSO response tropical eruptions. Here, these tested using ensemble simulations with Earth System Model in aerosols from a Tambora-like eruption confined either...

Abstract ENSO and the mean zonal sea surface temperature gradient (dSST) of tropical Pacific are important drivers global climate vary on decadal to centennial time scales. However, relationship between dSST cannot be assessed with short instrumental record, is uncertain in proxy data, intervals both stronger weaker postulated occur overall strong past. Here we assess ENSO–dSST during last millennium using general circulation models (GCMs) participating phase 3 Paleoclimate Modeling...

Abstract In this study, we investigate the relative contributions of dynamical forcings, particularly eastern and central‐western Pacific winds, thermodynamical forcings to evolution 2017 extreme coastal El Niño using observations modeling experiments. We show that competing effects anomalous westerlies easterlies their resulting downwelling upwelling equatorial Kelvin waves are essential for event, together with alongshore northerlies which suppress reduce latent heat release as discussed...