Abstract A theory is developed in a stochastic climate model for understanding the general features of seasonal predictability barrier (PB), which characterized by band maximum decline autocorrelation function phase-locked to particular season. Our determines forcing threshold, timing, and intensity PB as damping rate forcing. found be an intrinsic feature system forced either growth or noise generated when forcing, relative rate, exceeds modest threshold. Once generated, all PBs occur same...

Abstract The Southeast Indian Subantarctic Mode Water (SEISAMW), a thick water layer located between the seasonal and permanent pycnoclines, is important for climate variability in Southern Ocean. However, its impact on long‐term changes of Southeastern Front (SEF) associated with South Countercurrent has not been clearly revealed. By analyzing data from observations, objective products an eddy resolving ocean general circulation model, present study shows that SEISAMW shifted poleward...

The Indian Ocean dipole (IOD) is a remarkable interannual variability in the tropical Ocean. improved prediction of IOD great value because its large socioeconomic impacts. Previous studies reported that both El Ni˜ no-Southern Oscillation (ENSO) and South China Sea summer monsoon (SM) play dominant role western eastern pole IOD, respectively. They can be used as predictors at 3 month lead beyond self-persistence. Here, we develop an empirical model multi-factors which predicted by...

Abstract This paper investigates the impacts of tropical Atlantic on El Niño‐Southern Oscillation (ENSO) predictability through an empirical dynamical model‐ Linear Inverse Model (LIM). By selectively including or excluding coupling between and Pacific in LIM, we find that dynamics significantly improve Eastern (EP)‐ENSO prediction weaken EP‐ENSO barrier (PB), with Equatorial (EA) mode playing a more important role than Tropical North (TNA) mode. The Central (CP)‐ENSO PB are relatively...

Abstract El Niño-Southern Oscillation (ENSO) is the dominant mode of interannual climate variability in tropical Pacific, whose nature nevertheless may change significantly a warming climate. Here, we show that predictability ENSO decrease future. Across models Coupled Model Intercomparison Project Phase 6 (CMIP6), find robust persistence and for Central Pacific (CP) under global warming, notably passing through boreal spring. The strength spring barrier will be increased by 25% reduced CP...

To suppress vibration during robotic grinding of aero-engine blades caused by low stiffness and point-to-point movement, a novel metamaterial comprising double-nested auxetic structure local resonator is proposed. It simultaneously achieves enhanced-stiffness an ultra-low frequency wide-range band gap generated the hybrid auxetic-locally resonant characteristic. Young's modulus studied analytically numerically. A co-simulation procedure applied to obtain optimized (the bottom boundary 18.03...

The northern North Atlantic (NNA) subsurface temperature in response to the slowdown of meridional overturning circulation (AMOC) is crucial for ice sheet calving and recovery AMOC Heinrich events. Paleoclimate proxies modeling studies suggest that NNA exhibits a robust warming during 1, but with less clear Younger Dryas (YD). mechanism potentially different responses has remained not well understood. Previous show depending on hosing at locations. Here, by examining suite "water-hosing"...

Abstract The deglacial hydroclimate in South China remains a long-standing topic of debate due to the lack reliable moisture proxies and inconsistent model simulations. A recent proxy suggests that became wet cold stadials during last deglaciation, with intensification proposed be contributed mostly by East Asian summer monsoon (EASM). Here, based on simulation state-of-the-art climate well reproduces evolution EASM, winter (EAWM) associated water isotopes Asia, we propose intensified is...

Abstract This paper investigates the impacts of extratropical Pacific on El Niño‐Southern Oscillation (ENSO) spring predictability barrier (SPB). Using an empirical dynamical model – Linear Inverse Model (LIM), we find that dynamics northern and southern can significantly equally weaken Eastern (EP)‐ENSO SPB, while North is more important for weakening Central (CP)‐ENSO SPB. The evolution optimum initial structures illustrates different roles in crossing EP CP ENSO SPBs demonstrates decisive...

Abstract El Niño-Southern Oscillation (ENSO) asymmetry in predictability on springtime initial condition remains unclear. From the perspective of spring barrier (SPB), this paper investigates ENSO SPB and explores potential factors that may lead to asymmetry. Both observation 29 Coupled Model Intercomparison Project Phase 6 (CMIP6) models show sea surface temperature (SST) persistence is significantly higher Niño years than La Niña years, intensity stronger years. Through recharge oscillator...

Abstract Antarctic sea ice plays an important role in polar ecosystems and global climate, while its variability is affected by many factors. Teleconnections between the tropical high latitudes have profound impacts on climate changes through stationary Rossby wave mechanism. Recent studies connected long-term to multidecadal variabilities of ocean, including Atlantic Multidecadal Oscillation Interdecadal Pacific Oscillation. On interannual timescales, whether impact exists from...

Abstract Statistical model results suggest that the declining growth rate from autumn to spring is key cause El Niño‐Southern Oscillation (ENSO) persistence barrier (SPB). Using a dynamical approach, we develop physical mechanisms responsible for ENSO SPB in framework of recharge oscillator by adding seasonally varying Bjerknes (BJ) stability index and linking it with rate. By decomposing BJ index, indicated seasonal thermodynamic damping thermocline positive feedback play an important role...

Abstract This paper investigates potential factors that control the El Niño–Southern Oscillation (ENSO) Spring Persistence Barrier (SPB) strength in two different ENSO regimes and apply it to explain SPB modulation after 21st century. In a damped, noise‐driven model, theoretical solution of illustrates weaker growth rate strengthens SPB. self‐sustained regime, as Cane‐Zebiak model (chaotic system), strengthened thermodynamic damping weakened thermocline positive feedback lead more negative...

Abstract We performed parameter estimation in the Zebiak–Cane model for real-world scenario using approach of ensemble Kalman filter (EnKF) data assimilation and observational sea surface temperature wind stress analyses. With coupled model, our study shows that parameters converge toward stable values. Furthermore, new improve ENSO prediction skill, with skill improved most by highest climate sensitivity (gam2), which controls strength anomalous upwelling advection term SST equation. The is...

Abstract Prediction of El Niño–Southern Oscillation (ENSO) is hindered by a spring predictability barrier (SPB). In this paper, we investigate the effects Indian Ocean (IO) on SPB. Using seasonally varying extended IO–ENSO recharge oscillator model, find that SPB much weakened when IO coupled with ENSO. To gauge relative role dipole (IOD) and Basin (IOB) modes in weakening ENSO SPB, develop an empirical dynamical linear inverse model (LIM). By coupling/decoupling IOB or IOD mode ENSO, show...

Abstract In this paper, we investigate the relationship between El Niño–Southern Oscillation (ENSO) spring persistence barrier (PB) and predictability (PD) apply it to explain interdecadal modulation of ENSO prediction skill using anomaly correlation coefficient (ACC). Previous studies showed that a longer (i.e., autocorrelation) tends produce higher skill. Using recharge oscillator model ENSO, both analytical numerical solutions suggest ACC) is related sea surface temperature (SST) cross...

Abstract In this paper, we investigate the role of period El Niño–Southern Oscillation (ENSO) in spring persistence barrier (SPB), mainly using neutral recharge oscillator (NRO) model both analytically and numerically. It is suggested that a shorter ENSO strengthens SPB. Moreover, contrast to strict phase locking SPB Langevin equation, no longer locked exactly particular time calendar year NRO model. Instead, phases for different initial months shift earlier with lag maximum decline....

Abstract The atmosphere‐ocean is a highly coupled system with significant diurnal and hourly variations. However, current models usually lack sub‐diurnal scale processes at the air‐sea interface due to finite vertical resolution for ocean discretization. Previous modeling studies showed that interaction are important mixing. Here, by designing an integrated parameterization (ISDP) scheme which combines different temperature profiling functions, we stress interactions better represent local...

The El Niño-Southern Oscillation (ENSO), originating in the central and eastern equatorial Pacific, is a defining mode of interannual climate variability with profound impact on global ecosystems. However, an understanding how ENSO might have evolved over geological timescales still lacking, despite well-accepted recognition that such has direct implications for constraining human-induced future changes. Here, using simulations, we show been leading tropical sea surface temperature (SST)...

Abstract In this paper, we investigate the relationship between upper ocean heat content (OHC) and El Niño–Southern Oscillation (ENSO) sea surface temperature (SST) anomalies mainly using neutral recharge oscillator (NRO) model both analytically numerically. Previous studies showed that spring OHC, which leads SST by 6–12 months, represents a major source of predictability for ENSO. It is suggested seasonality caused seasonally varying growth rate in anomalies. Moreover, shortened ENSO...

Abstract The mechanism of the seasonal persistence barrier (SPB) is studied in framework an autoregressive (AR) model. In contrast to variance, whose minimum modulated mainly by growth rate or noise forcing, SPB caused primarily declining increasing instead minimum/maximum forcing. other words, signal-to-noise ratio (SNR) rather than weakest SNR. a weakly damped system, phase delayed from that SNR about season. further applied explain observed SST variability tropical and North Pacific. For...