State Response Research Articles

Civil Society, Community, Disaster and State Responses: A Critical Study on Ockhi Cyclone 2017, Floods in 2018 and 2019 in Kerala, India

Civil Society, Community, Disaster and State Responses: A Critical Study on Ockhi Cyclone 2017, Floods in 2018 and 2019 in Kerala, India

ShakeAlert® and schools: Incorporating earthquake early warning in school districts in Alaska, California, Oregon, and Washington

The U.S. Geological Survey-managed ShakeAlert® earthquake early warning system is the first public alerting system in the United States to provide rapid mass notification when an earthquake is detected. Although public alert delivery via mobile phones began in California in 2019 followed by Oregon and Washington in 2021, little is known about what might drive widespread implementation in at-risk institutional settings such as schools. For example, there has been limited research on how to best integrate earthquake early warning into existing emergency plans, alert systems, and drills to keep school children and personnel safe in an earthquake. To address this gap, in the spring of 2022, every school district superintendent in Alaska, California, Oregon, and Washington was sent a 15-min online survey. The survey assessed superintendent knowledge of ShakeAlert, preferences for alert messaging, and perceived opportunities and barriers to incorporating the system in schools. The results showed that superintendents had low awareness of ShakeAlert but held positive perceptions of the system's potential to enable life-saving protective actions. A major barrier to adoption included the perceived financial cost of implementing and maintaining the system. There were some statistically significant differences in state responses, and future research could investigate the specific needs of each state based on school district size and composition, hazard exposure, and earthquake experience. Together these findings can help inform targeted strategies to increase ShakeAlert adoption in schools and ultimately improve the safety of school children and staff during earthquakes.

Investigation on dynamic modelling and nonlinear vibration behaviors of composite structures: A case of cable-beam model

This paper conducts a nonlinear analysis of cable-beam model of cable-stayed bridges by using the exact mode superposition method (EMSM) and the cable-beam dragging method (CBDM), respectively, comparing and exploring their theoretical foundations and practical implications. The EMSM is based on the global mode function of the cable-beam structure for nonlinear analysis, yet it requires more computational resources. The CBDM is based on the cable-beam dragging equations for nonlinear analysis, which can quickly obtain the static equilibrium state and dynamic response of the cable-beam system, but it requires some simplifying assumptions on the cable-beam connection conditions. Research results demonstrate qualitative and quantitative differences between these two methods through parametric analysis on dynamic behaviors, which provide a significant methodological study and a reference for the design and dynamics of composite structures.

Policy-specific human rights shaming: Evidence from the other letters of the UN Special Procedures

This study provides empirical insights into “other letters” (OLs) issued by the UN Special Procedures, a unique tool of policy-specific human rights shaming. By analyzing criticized laws, recipients, state responses, and impact, the study reveals that OLs are predominantly targeted at cooperative states. Despite better human rights records, democracies receive more OLs and they are more likely to implement the recommendations. Authoritarian states receive fewer OLs and tend to reject the allegations. The study highlights the intricate dynamics shaping interactions between UN human rights mechanisms and states, emphasizing democratic responsiveness while underscoring the challenges of addressing abuses in nondemocratic settings.

Developmental trajectory and sex differences in auditory processing in a PTEN-deletion model of autism spectrum disorders

Autism Spectrum Disorders (ASD) encompass a wide array of debilitating symptoms, including severe sensory deficits and abnormal language development. Sensory deficits early in development may lead to broader symptomatology in adolescents and adults. The mechanistic links between ASD risk genes, sensory processing and language impairment are unclear. There is also a sex bias in ASD diagnosis and symptomatology. The current study aims to identify the developmental trajectory and genotype- and sex-dependent differences in auditory sensitivity and temporal processing in a Pten-deletion (phosphatase and tensin homolog missing on chromosome 10) mouse model of ASD. Auditory temporal processing is crucial for speech recognition and language development and deficits will cause language impairments. However, very little is known about the development of temporal processing in ASD animal models, and if there are sex differences. To address this major gap, we recorded epidural electroencephalography (EEG) signals from the frontal (FC) and auditory (AC) cortex in developing and adult Nse-cre PTEN mice, in which Pten is deleted in specific cortical layers (layers III-V) (PTEN conditional knock-out (cKO). We quantified resting EEG spectral power distribution, auditory event related potentials (ERP) and temporal processing from awake and freely moving male and female mice. Temporal processing is measured using a gap-in-noise-ASSR (auditory steady state response) stimulus paradigm. The experimental manipulation of gap duration and modulation depth allows us to measure cortical entrainment to rapid gaps in sounds. Temporal processing was quantified using inter-trial phase clustering (ITPC) values that account for phase consistency across trials. The results show genotype differences in resting power distribution in PTEN cKO mice throughout development. Male and female cKO mice have significantly increased beta power but decreased high frequency oscillations in the AC and FC. Both male and female PTEN cKO mice show diminished ITPC in their gap-ASSR responses in the AC and FC compared to control mice. Overall, deficits become more prominent in adult (p60) mice, with cKO mice having significantly increased sound evoked power and decreased ITPC compared to controls. While both male and female cKO mice demonstrated severe temporal processing deficits across development, female cKO mice showed increased hypersensitivity compared to males, reflected as increased N1 and P2 amplitudes. These data identify a number of novel sensory processing deficits in a PTEN-ASD mouse model that are present from an early age. Abnormal temporal processing and hypersensitive responses may contribute to abnormal development of language function in ASD.

Study on Rural Classification and Resilience Evaluation Based on PSR Model: A Case Study of Lvshunkou District, Dalian City, China

When implementing a rural revitalization strategy, it is of great significance to understand how to identify potential risks in different types of villages and how to achieve resilience governance. In this paper, a rural classification evaluation method is proposed from the perspective of resilience. The stress–state–response model and the TOPSIS method were used to analyze the resilience risks in different types of villages in Lvshunkou District. The results showed that the comprehensive resilience of rural areas in Lvshunkou District has the spatial distribution characteristics of “high center and low wings”, and the spatial differences of each resilience subsystem are different: the pressure resilience subsystem shows a trend of “increasing step by step” from the coast to the inland, the state resilience subsystem shows a trend of “decreasing step by step from the center to the two wings”, and the response resilience subsystem shows a trend of “blocky aggregation and balanced distribution”. This paper further proposes systematic reconstruction strategies for rural resilience related to the four aspects of rural space, industry, ecology, and governance, providing development ideas for measuring rural resilience indicators in Lvshunkou District and realizing long-term governance in different types of villages.

Credit in agrarian India: narrative policy struggles over farmer surplus

Debt is fundamental to agrarian life across the world. In India, over half of agricultural households are indebted and borrow from myriad credit sources. Formal institutional credit (e.g., bank loans) has historically, and up to the present day, been proposed as a tool for rural development and to eliminate exploitative informal moneylenders. This is true in India, where despite decades of state policies to displace informal lending using formal credit, informal lending persists and increasing debt is an ever-present symptom of the agrarian crisis. Informal lending made up 30% of farmers’ credit sources in 2019; for farmers who owned less than 0.01 ha of land, this was 71.8%. In this paper we provide an historical examination of the numerous state responses to the proliferation of agrarian debt, surveying lending policy as a state development tool in India. We analyze how moneylending has been treated in different historical periods and the increasing participation of the state (from colonial to present times) in agrarian debt and use a Narrative Policy Analysis to synthesize the underlying “narratives” that characterize evolving policy forms. In the process, we reveal not only a consistent narrative assuming the displacement of informal credit with formal credit, one contradicted by the situation on the ground: an absolute increasing trend in borrowing, and a crucial propagation of the number and variety of credit sources. This we observe to be precisely a result of the largely fruitless state effort to formalize credit and to eliminate informal lending. This persistent discourse that posits formality as a solution to informality, we further conclude, is not only a cultural project of the colonial, post-colonial, and modernization state, but one essential for the circulation and accumulation of capital, enhancing its urgency. The failed effort to eliminate informal lending has resulted, furthermore, in a decline in farmer autonomy and the creation of a state-underwritten struggle − between multiple actors in the credit sector − over the redistribution of agrarian surplus.

Effects of acute simulated altitude on the maximal lactate steady state in humans.

We sought to determine the effects of acute simulated altitude on the maximal lactate steady state (MLSS) and physiological responses to cycling at and 10 W above the MLSS-associated power output (PO) (MLSSp and MLSSp+10, respectively). Eleven (4 females) participants (means [SD]; 28 [4] yr; V̇o2max: 54.3 [6.9] mL·kg-1·min-1) acclimatized to ∼1,100 m performed 30-min constant PO trials in simulated altitudes of 0 m sea level (SL), 1,111 m mild altitude (MILD), and 2,222 m moderate altitude (MOD). MLSSp, defined as the highest PO with stable (<1 mM change) blood lactate concentration ([BLa]) between 10 and 30 min, was significantly lower in MOD (209 [54] W) compared with SL (230 [56] W; P < 0.001) and MILD (225 [58] W; P = 0.001), but MILD and SL were not different (P = 0.12). V̇o2 and V̇co2 decreased at higher simulated altitudes due to lower POs (P < 0.05), but other end-exercise physiological responses (e.g., [BLa], ventilation [V̇e], heart rate [HR]) were not different between conditions at MLSSp or MLSSp + 10 (P > 0.05). At the same absolute intensity (MLSSp for MILD), [BLa], HR, and V̇E and all perceptual variables were exacerbated in MOD compared with SL and MILD (P < 0.05). Maximum voluntary contraction, voluntary activation, and potentiated twitch forces were exacerbated at MLSSp + 10 relative to MLSSp within conditions (P < 0.05); however, condition did not affect performance fatiguability at the same relative or absolute intensity (P > 0.05). As MLSSp decreased in hypoxia, adjustments in PO are needed to ensure the same relative intensity across altitudes, but common indices of exercise intensity may facilitate exercise prescription and monitoring in hypoxia.NEW & NOTEWORTHY This study demonstrates the power output and metabolic rate associated with the maximal lactate steady-state (MLSS) decline in response to simulated altitude; however, common indices of exercise intensity remained unchanged when cycling was performed at the work rate associated with MLSS at each simulated altitude. These results support previous studies that investigated the effects of hypoxia on alternative measures of the critical intensity of exercise and will inform exercise prescription/monitoring across altitudes.

Neurophysiological, structural, and molecular alterations in the prefrontal and auditory cortices following noise-induced hearing loss

It is well established that hearing loss can lead to widespread plasticity within the central auditory pathway, which is thought to contribute to the pathophysiology of audiological conditions such as tinnitus and hyperacusis. Emerging evidence suggests that hearing loss can also result in plasticity within brain regions involved in higher-level cognitive functioning like the prefrontal cortex; findings which may underlie the association between hearing loss and cognitive impairment documented in epidemiological studies. Using the 40-Hz auditory steady state response to assess sound-evoked gamma oscillations, we previously showed that noise-induced hearing loss results in impaired gamma phase coherence within the prefrontal but not the auditory cortex. To determine whether region-specific structural or molecular changes accompany this differential plasticity following hearing loss, in the present study we utilized Golgi-Cox staining to assess dendritic organization and synaptic density, as well as Western blotting to measure changes in synaptic signaling proteins in these cortical regions. We show that following noise exposure, impaired gamma phase coherence within the prefrontal cortex is accompanied by alterations in pyramidal cell dendritic morphology and decreased expression of proteins involved in GABAergic (GAD65) and glutamatergic (NR2B) neurotransmission; findings that were not observed in the auditory cortex, where gamma phase coherence remained unchanged post-noise exposure. In contrast to the noise-induced effects we observed in the prefrontal cortex, plasticity in the auditory cortex was characterized by an increase in NR2B suggesting increased excitability, as well as increases in the synaptic proteins PSD95 and synaptophysin within the auditory cortex. Overall, our results highlight the disparate effect of noise-induced hearing loss on auditory and higher-level brain regions as well as potential structural and molecular mechanisms by which hearing loss may contribute to impaired cognitive and sensory functions mediated by the prefrontal and auditory cortices.

Ecological Evaluation of Land Resources in the Yangtze River Delta Region by Remote Sensing Observation

The evaluation of land ecological security (LES) evaluates how human activity and land use affect land ecosystems. Its ultimate objective is to provide guidance and assistance for decision making in order to preserve and restore the efficacy and health of terrestrial ecosystems. The assessment model presented in this article is comprehensive and integrates the advantages of both subjective and objective weighting techniques. This study extends the “Pressure–State–Response” (PSR) model to “Driver–Pressure–State-Impact–Response” (DPSIR) and combines it with TOPSISI to determine the weights of each contributing component. Furthermore, the geographical and temporal distribution patterns of regional land ecological security levels were investigated using GIS geostatistical approaches. According to this study, (1) the Yangtze River Delta region’s LES index, with a mean value in the fairly safe range, is generally safe. The year 2019 marks an inflection point for the index, with the highest level of ecological safety on land. The primary element is the modification of environmental policies that are enacted by the government. (2) The LES status is divided into two stages during the course of this study. The Yangtze River Delta region’s LES quickly develops throughout the first stage (2012–2019), which sees a shift in the safety rating from IV to II. The second stage (2019–2023) sees a progressive improvement in the LES index and a shift in the safety category from Class II to Class I. (3) Important variables influencing the geographical distribution of LES in the Yangtze River Delta region include barrier elements, including soil and water erosion areas, flood disaster areas, grain planting areas, urban green covering areas, and effective irrigation areas of farmland.

Third-order nonlinear Hall effect in a quantum Hall system.

In two-dimensional systems, perpendicular magnetic fields can induce a bulk band gap and chiral edge states, which gives rise to the quantum Hall effect. The quantum Hall effect is characterized by zero longitudinal resistance (Rxx) and Hall resistance (Rxy) plateaus quantized to h/(υe2) in the linear response regime, where υ is the Landau level filling factor, e is the elementary charge and h is Planck's constant. Here we explore the nonlinear response of monolayer graphene when tuned to a quantum Hall state. We observe a third-order Hall effect that exhibits a nonzero voltage plateau scaling cubically with the probe current. By contrast, the third-order longitudinal voltage remains zero. The magnitude of the third-order response is insensitive to variations in magnetic field (down to ~5 T) and in temperature (up to ~60 K). Moreover, the third-order response emerges in graphene devices with a variety of geometries, different substrates and stacking configurations. We term the effect third-order nonlinear response of the quantum Hall state and propose that electron-electron interaction between the quantum Hall edge states is the origin of the nonlinear response of the quantum Hall state.

Network resonance and the auditory steady state response

The auditory steady state response (ASSR) arises when periodic sounds evoke stable responses in auditory networks that reflect the acoustic characteristics of the stimuli, such as the amplitude of the sound envelope. Larger for some stimulus rates than others, the ASSR in the human electroencephalogram (EEG) is notably maximal for sounds modulated in amplitude at 40 Hz. To investigate the local circuit underpinnings of the large ASSR to 40 Hz amplitude-modulated (AM) sounds, we acquired skull EEG and local field potential (LFP) recordings from primary auditory cortex (A1) in the rat during the presentation of 20, 30, 40, 50, and 80 Hz AM tones. 40 Hz AM tones elicited the largest ASSR from the EEG acquired above auditory cortex and the LFP acquired from each cortical layer in A1. The large ASSR in the EEG to 40 Hz AM tones was not due to larger instantaneous amplitude of the signals or to greater phase alignment of the LFP across the cortical layers. Instead, it resulted from decreased latency variability (or enhanced temporal consistency) of the 40 Hz response. Statistical models indicate the EEG signal was best predicted by LFPs in either the most superficial or deep cortical layers, suggesting deep layer coordinators of the ASSR. Overall, our results indicate that the recruitment of non-uniform but more temporally consistent responses across A1 layers underlie the larger ASSR to amplitude-modulated tones at 40 Hz.

Numerical Study of the Ultra-High-Speed Aerodynamically Alleviated Marine Vehicle Motion Stability in Winds and Waves

The ultra-high-speed aerodynamically alleviated marine vehicle (AAMV) is a high-performance vessel that combines a hydrodynamic configuration and an aerodynamic wing to reduce wave-making resistance during the high-speed planing phase. The forces of the AAMV exhibit strong nonlinear and water–air coupling characteristics, resulting in particularly complex motion characteristics. This paper presents a longitudinal and lateral stability model of the AAMV, which considers the effects of aerodynamic alleviation. Additionally, a numerical model of wind and wave turbulence forces is established, which considers viscous correction based on the potential theory. Finally, the effect of wind and wave turbulence forces on the motion stability of the AAMV under regular and irregular waves is analyzed by numerical solution. The simulation results demonstrate the influence of these disturbance forces on the stability of the AAMV under different sea states. The motion parameters of the AAMV exhibit a pronounced response to changes in sea state level. The aerodynamically alleviated effect is enhanced as speed increases, and the influence of winds and waves on the AAMV is greatly weakened, reducing the possibility of instability. During the cruising phase under class V sea state, the pitch, roll, and heave response are 0.210°, 0.0229°, and 0.0734 m, respectively. This effect can effectively improve the motion stability of the AAMV in winds and waves.

Spatiotemporal Changes and Simulation Prediction of Ecological Security Pattern on the Qinghai–Tibet Plateau Based on Deep Learning

Over the past two decades, due to the combined effects of natural and human factors, the ecological environment and resources of the Qinghai–Tibet Plateau (QTP) have faced serious threats, profoundly impacting its ecosystem and the lives of its residents. Therefore, the establishment of the ecological security pattern (ESP) is crucial to cope with climate change, maintain ecosystem function, and sustainable development. Based on the Pressure–State–Response (PSR) model, this study constructed an evaluation index system for the ecological security (ES) of the QTP, evaluated the ES of the QTP during 2000–2020, and predicted the ES of the QTP during 2025–2035 based on the deep learning model. Combined with the residents’ perception of ES, the ES of the QTP was evaluated comprehensively. The results showed that: (1) From 2000 to 2020, the ES value of the QTP continued to rise, the number of dangerous and sensitive counties decreased, and the number of other counties increased. The overall spatial distribution features higher values in the southeast and lower values in the northwest and central regions. (2) From 2000 to 2020, both hot spots and cold spots on the QTP decreased, with the hot spots mainly concentrated in the southeast of the QTP, represented by Yunnan Province, and the cold spots shifting from west to east, mainly concentrated in the central QTP, represented by Qinghai Province. (3) The Long Short-Term Memory (LSTM) model demonstrates high prediction accuracy. Based on the prediction of LSTM, the ES value of the QTP will continue to rise from 2025 to 2035, and the number of safe counties will reach the highest level in history. The spatial distribution is still higher in the southeast and lower in the northwest and central regions. (4) By analyzing residents’ perception of 25 potential factors that may affect the ES of the QTP, the results show that residents generally believe that these factors have an important impact on ES, and their evaluation is between “important” and “very important”. In addition, there is a significant correlation between these factors and the predicted values of ES. The results of the study will help to improve our understanding of the overall ecological environment of the QTP, provide accurate positioning and reasonable help for the government to formulate relevant protection strategies, and lay a methodological and practical foundation for the sustainable development of the QTP.

Tactics and Targets: Labor Protest and State Response in China

ABSTRACT Repression has long been regarded as the main response of the state when encountering contentious actions. Although recent studies point out that repression may vary by regime types and state-level concerns regarding international reputation, few analyses to date have analyzed how movement dynamics and movement targets jointly shape state responses. In this article, I analyze over 7,500 episodes of labor protests in mainland China to advance scholarship on state responses to social movements. I develop a typology of state responses, from active coercion to accommodation and even tolerance. I then explore differences in state responses based on protest tactics and whether they are against private or state-affiliated targets. My results show that state responses differ based on the tactics that movements employ. Furthermore, these effects are moderated by whether activists target state-affiliated or private entities. This research offers important insights into the dynamic relations between state and social movement, the diverse ways highly bureaucratic governments use to manage social unrest, and the conflict between maintaining legitimacy and social control in both authoritarian and democratic contexts.

Favourable clinical outcomes and low revision rate after M-ACI in adolescents with immature cartilage compared to adult controls: Results at 10 years.

The purpose of this study was to evaluate long-term survival, patient-reported outcomes (PROs)and radiographic results of matrix-associated autologous chondrocyte implantation (M-ACI) in adolescents with immature cartilage and compare them to adult controls. A retrospective matched-pair analysis was performed comparing the PRO after M-ACI for focal cartilage defect of the knee in cartilaginous immature adolescents to mature adults. Groups were matched for sex, body mass index, defect site and size, symptom duration and the number of previous knee surgeries. Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART 2.0) scores were assessed at least 60 months postoperatively. Patient acceptable symptomatic state (PASS) and clinical response rate in KOOS and KOOS subscores were calculated. A total of 54 patients were matched. At a mean of 96 months (65-144 months), no surgical complications, graft hypertrophy or reoperations were noted in the cohorts studied. Adolescents showed superior PROs at the final follow-up (76.9 ± 14.1 vs. 66.4 ± 15.0, p = 0.03) and were significantly more likely to achieve PASS (74.1% vs. 55.6%; p = 0.02) compared to the adult cohort. The KOOS subscale analysis showed long-term benefits for adolescents in terms of symptom improvement, pain reduction, activities of daily living, sports and quality of life (p < 0.05). None of the patients in the adolescent group showed graft hypertrophy on magnet resonance imaging or signs of osteoarthritis on radiographs at long-term follow-ups. M-ACI is an effective treatment for chondral defects of the knee in patients with immature cartilage with low revision rates and high patient satisfaction over the long term. Adolescents showed comparable clinical and radiographic results in the short and medium term, with slightly more favourable, clinically relevant functional results in adolescents in the long term. M-ACI can be safely used in adolescents, and consideration should be given to expanding the indication to include these patients. Level III.

Local Australian memory activism and the fast and slow violence of institutional abuse

ABSTRACT This article investigates unofficial memory projects that have arisen in Australia in response to the institutional abuse of children. While the role of activists in pushing for the enactment of state responses is beginning to be understood, activist demands for recognition have taken a multitude of forms beyond this. Unofficial memory projects are indicative of this, exemplified by a diverse range of publicly situated cultural forms that re-present abuse to wider audiences. Focusing on two examples that have arisen in Australia in recent years – the grassroots phenomenon known as Loud Fence that grew out of the Victorian town of Ballarat, and the Australian Orphanage Museum that was established by Care leavers in 2023 – I examine these as examples of memory activism which generate counter-archives of institutional violence against children. Loud Fence does so upon institutional fences at the level of the streetscape, while the AOM does so by curating a museum space that honours the experiences of childhood ‘Care’. Seeking to decentre the state from this analysis, I demonstrate how such examples enliven the fast and slow violence of child abuse and neglect, and the role of non-state actors when it comes to the recalibration of collective memory.

Isothermal Amplification Using Temperature-Controlled Frequency Mixing Magnetic Detection-Based Portable Field-Testing Platform.

Sensitive magnetic nucleic acid (NA) detection via frequency mixing magnetic detection (FMMD) requires amplified NA samples for which a reliable temperature control is necessary. The feasibility of recombinase polymerase amplification (RPA) was studied within a newly integrated temperature-controlled sensor unit of a mobile FMMD based setup. It has been demonstrated that the inherently generated heat of the low frequency (LF) excitation signal of FMMD can be utilized and controlled by means of pulse width modulation (PWM). To test control performance in a point of care (PoC) setting with changing ambient conditions, a steady state and dynamic response model for the thermal behavior at the sample position of the sensor were developed. We confirmed that in the sensor unit of the FMMD device, RPA performs similar as in a temperature-controlled water bath. For narrow steady state temperature regions, a linear extrapolation suffices for estimation of the sample position temperature, based on the temperature feedback sensor for PWM control. For any other ambient conditions, we identified and validated a lumped parameter model (LPM) performing with high estimation accuracy. We expect that the method can be used for NA amplification and magnetic detection using FMMD in resource-limited settings.

Modelling of foundation damping in time-domain analysis of monopile supported offshore wind turbine structures

Foundation damping holds large potential for design optimisations of monopile-supported offshore wind turbine structures. However, the contribution of foundation damping is not well understood, in part due to lack of suitable method for incorporating foundation damping in the time-domain analysis of wind turbine structures. This paper presents a practical approach for this purpose in which a dashpot is attached in parallel to each p-y spring along the monopile. In this way, the distributed soil-pile interaction stiffness and damping are accurately modelled. To demonstrate the validity of the proposed approach, a case study exploring the influence of foundation damping on the dynamic response of an IEA 15 MW reference turbine founded on monopile is carried out. The results demonstrate that the foundation damping has relatively limited impact on the overall dynamic response and fatigue loads in power production states. However, inclusion of foundation damping is shown to significantly reduce the structural response after emergency shutdown and under parked conditions. The findings of the case study show promising potential for wind turbine structure design optimization through consideration of foundation damping.

Role of the Antarctic Circumpolar Circulation in Current Asymmetric Arctic and Antarctic Warming

AbstractBoth historical observations and recent modeling studies reveal a faster warming in the Arctic compared to the Antarctic. To understand the role of the Antarctic Circumpolar Circulation (ACC) in this warming asymmetry, we simulate the climate mean state and climate response to doubled CO2 under different climate mean ACC states by closing or opening the Drake Passage (DP) with the Community Earth System Model. From closed to open DP, a stronger climate mean ACC leads to a stronger climate mean Atlantic Meridional Overturning Circulation (AMOC), as well as a colder Antarctic but a warmer Arctic in the climate mean state. The less climate mean sea ice coverage in a warmer Arctic implies less extensive sea ice melting under global warming. This causes a reduced asymmetry in warming between the two poles in response to the doubled CO2.