El Niño and Southern Oscillation (ENSO) is the most prominent year‐to‐year climate fluctuation on Earth, alternating between anomalously warm (El Niño) and cold (La Niña) sea surface temperature ...(SST) conditions in the tropical Pacific. ENSO exerts its impacts on remote regions of the globe through atmospheric teleconnections, affecting extreme weather events worldwide. However, these teleconnections are inherently nonlinear and sensitive to ENSO SST anomaly patterns and amplitudes. In addition, teleconnections are modulated by variability in the oceanic and atmopsheric mean state outside the tropics and by land and sea ice extent. The character of ENSO as well as the ocean mean state have changed since the 1990s, which might be due to either natural variability or anthropogenic forcing, or their combined influences. This has resulted in changes in ENSO atmospheric teleconnections in terms of precipitation and temperature in various parts of the globe. In addition, changes in ENSO teleconnection patterns have affected their predictability and the statistics of extreme events. However, the short observational record does not allow us to clearly distinguish which changes are robust and which are not. Climate models suggest that ENSO teleconnections will change because the mean atmospheric circulation will change due to anthropogenic forcing in the 21st century, which is independent of whether ENSO properties change or not. However, future ENSO teleconnection changes do not currently show strong intermodel agreement from region to region, highlighting the importance of identifying factors that affect uncertainty in future model projections.
Key Points
The character of ENSO as well as the ocean mean state has changed since the 1990s, resulting in changes in ENSO atmospheric teleconnections
Changes in ENSO teleconnection patterns have affected their predictability and the statistics of extreme events
Climate models suggest that changes in the mean atmospheric circulation will affect ENSO teleconnections in the 21st century
Most trials comparing percutaneous coronary intervention (PCI) with coronary-artery bypass grafting (CABG) have not made use of second-generation drug-eluting stents.
We conducted a randomized ...noninferiority trial at 27 centers in East Asia. We planned to randomly assign 1776 patients with multivessel coronary artery disease to PCI with everolimus-eluting stents or to CABG. The primary end point was a composite of death, myocardial infarction, or target-vessel revascularization at 2 years after randomization. Event rates during longer-term follow-up were also compared between groups.
After the enrollment of 880 patients (438 patients randomly assigned to the PCI group and 442 randomly assigned to the CABG group), the study was terminated early owing to slow enrollment. At 2 years, the primary end point had occurred in 11.0% of the patients in the PCI group and in 7.9% of those in the CABG group (absolute risk difference, 3.1 percentage points; 95% confidence interval CI, -0.8 to 6.9; P=0.32 for noninferiority). At longer-term follow-up (median, 4.6 years), the primary end point had occurred in 15.3% of the patients in the PCI group and in 10.6% of those in the CABG group (hazard ratio, 1.47; 95% CI, 1.01 to 2.13; P=0.04). No significant differences were seen between the two groups in the occurrence of a composite safety end point of death, myocardial infarction, or stroke. However, the rates of any repeat revascularization and spontaneous myocardial infarction were significantly higher after PCI than after CABG.
Among patients with multivessel coronary artery disease, the rate of major adverse cardiovascular events was higher among those who had undergone PCI with the use of everolimus-eluting stents than among those who had undergone CABG. (Funded by CardioVascular Research Foundation and others; BEST ClinicalTrials.gov number, NCT00997828.).
This study conducted a detection and attribution analysis of the observed global and regional changes in extreme temperatures during 1951–2015. HadEX3 observations were compared with multimodel ...simulations from the Coupled Model Intercomparison Project phase 6 (CMIP6) using an optimal fingerprinting technique. Annual maximum daily maximum and minimum temperatures (TXx and TNx; warm extremes) and annual minimum daily maximum and minimum temperatures (TXn and TNn; cold extremes) over land were analyzed considering global, continental, and subcontinental scales. Response patterns (fingerprints) of extreme temperatures to anthropogenic (ANT), greenhouse gases (GHG), aerosols (AA), and natural (NAT) forcings were obtained from CMIP6 forced simulations. The internal variability ranges were estimated from preindustrial control simulations. A two-signal detection analysis where the observations are regressed onto ANT and NAT fingerprints simultaneously reveals that ANT signals are robustly detected in separation from NAT over global and all continental domains (North and South America, Europe, Asia, and Oceania) for most of the extreme indices. ANT signals are also detected over many subcontinental regions, particularly for warm extremes (more than 60% of 33 subregions). A three-signal detection analysis that considers GHG, AA, and NAT fingerprints simultaneously demonstrates that GHG signals are detected in isolation from other external forcings over global, continental, and several subcontinental domains especially for warm extremes, explaining most of the observed warming. Moreover, AA influences are detected for warm extremes over Europe and Asia, indicating significant offsetting cooling contributions. Overall, human influences are detected more frequently, compared to previous studies, particularly for cold extremes, due to the extended period and the improved spatial coverage of observations.
This study provides estimates of the human contribution to the observed widespread intensification of precipitation extremes. We consider the annual maxima of daily (RX1day) and 5 day consecutive ...(RX5day) precipitation amounts over the Northern Hemisphere land area for 1951–2005 and compare observed changes with expected responses to external forcings as simulated by multiple coupled climate models participating in Coupled Model Intercomparison Project Phase 5. The effect of anthropogenic forcings can be detected in extreme precipitation observations, both individually and when simultaneously estimating anthropogenic and naturally forced changes. The effect of natural forcings is not detectable. We estimate that human influence has intensified annual maximum 1 day precipitation in sampled Northern Hemisphere locations by 3.3% 1.1% to 5.8%, >90% confidence interval on average. This corresponds to an average intensification in RX1day of 5.2% 1.3%, 9.3% per degree increase in observed global mean surface temperature consistent with the Clausius‐Clapeyron relationship.
Key Points
Extreme precipitation intensification attributable to human influence
Observed and simulated changes in extreme precipitation consistent
Model projected future changes may be reliable
Using Generalized Extreme Value analysis, this study details the independent seasonal impacts of the El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) on rainfall extremes that cause ...many hydro‐meteorological hazards and affect vulnerable populations in Indonesia, based on indices defined by the Expert Team on Climate Change Detection and Indices (ETCCDI), for the period 1981–2019. Gridded Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) is used to calculate maximum consecutive 5‐day precipitation (Rx5d), total precipitation from days above 95 percentile (R95p), and maximum number of consecutive dry days (CDD). Consistent with previous studies, the ENSO and IOD impacts on rainfall extremes are shown to be strongest during the dry seasons (JJA‐SON) and weaker in the wet seasons (DJF‐MAM). Rainfall extremes appear to be widely influenced throughout Indonesia by ENSO, whereby extremes become drier (wetter) during El Niño (La Niña). Similarly, positive (negative) phases of the IOD lead to more extreme dry (wet) conditions. However, distinct from previous studies, as ENSO and IOD often co‐occur, we also provide independent influences of the two climate modes. Low‐level circulation northeast and southwest of Indonesia, both previously suggested as main drivers of impacts on Maritime Continent rainfall, are more closely associated with independent ENSO and IOD, respectively. For example, ENSO, independent of IOD, impacts rainfall extremes more in the northern and eastern regions of Indonesia, and the IOD, independent of ENSO, modulates rainfall extremes more over southern and western regions. Despite independent ENSO and IOD impacts understandably being found more eastward and westward of the country, respectively, details provided here help explain regional differences between rainfall extremes and ENSO and IOD, such as Jakarta in west Java, which is predominantly influenced by local forcing associated with the IOD.
The ENSO and IOD impacts on rainfall extremes throughout Indonesia are shown to be the strongest during the dry seasons and weaker in the wet seasons. Rainfall extremes appear to be widely influenced throughout Indonesia by ENSO and IOD, whereby extremes become drier (wetter) during El Niño (La Niña), or positive (negative) IOD phases. ENSO, independent of IOD, impacts rainfall extremes more in the northern and eastern Indonesia, and the IOD, independent of ENSO, modulating more over southern and western regions.
This study provides a first quantification of possible benefits of global warming mitigation through heat stress reduction over East Asia by comparing projection results between low-emission and ...high-emission scenarios, as well as between 1.5° and 2.0°C target temperature conditions. Future changes in summer heat stress over East Asia were examined based on the wet-bulb globe temperature (WBGT) using CMIP5 multimodel simulations. Changes in the intensity, frequency, and duration of heat stress were analyzed in terms of area fraction across RCP2.6, RCP4.5, and RCP8.5 scenarios and also between two selected model groups representing 1.5°-and 2.0°C-warmer worlds. Severe heat stress, exceeding the 50-yr return value of the present-day period, is expected to become very frequent, occurring every second year over the large part of East Asia by the 2040s, irrespective of RCP scenarios. The frequency of extreme daily heat stress events is predicted to increase in a similar speed of expansion, with signals emerging from the low latitudes. The WBGT signal emergence is found to be much faster than that of corresponding temperature alone due to the smaller variability in WBGT, supporting previous findings. The 1.5°C-warmer world would have about 20% reduction in areas experiencing severe heat stress over East Asia, compared to the 2.0°C-warmer world, with significant changes identified over the low latitudes. Further, compared to the transient world, the equilibrium world exhibits larger increases in heat stress over East Asia, likely due to the warmer ocean surface in the northwestern North Pacific. This suggests an important role of ocean warming patterns in the regional assessment of global warming mitigation.
While the IPCC Fifth Assessment Working Group I report assessed observed changes in extreme precipitation on the basis of both absolute and percentile-based extreme indices, human influence on ...extreme precipitation has rarely been evaluated on the basis of percentile-based extreme indices. Here we conduct a formal detection and attribution analysis on changes in four percentile-based precipitation extreme indices. The indices include annual precipitation totals from days with precipitation exceeding the 99th and 95th percentiles of wet-day precipitation in 1961–90 (R99p and R95p) and their contributions to annual total precipitation (R99pTOT and R95pTOT). We compare these indices from a set of newly compiled observations during 1951–2014 with simulations from models participating in phase 6 of the Coupled Model Intercomparison Project (CMIP6). We show that most land areas with observations experienced increases in these extreme indices with global warming during the historical period 1951–2014. The new CMIP6 models are able to reproduce these overall increases, although with considerable over- or underestimations in some regions. An optimal fingerprinting analysis reveals detectable anthropogenic signals in the observations of these indices averaged over the globe and over most continents. Furthermore, signals of greenhouse gases can be separately detected, taking other forcing into account, over the globe and over Asia in these indices except for R95p. In contrast, signals of anthropogenic aerosols and natural forcings cannot be detected in any of these indices at either global or continental scales.
This study conducts a detection and attribution analysis of the observed changes in extreme precipitation during 1951–2015. Observed and CMIP6 multimodel simulated changes in annual maximum daily and ...consecutive 5‐day precipitation are compared using an optimal fingerprinting technique for different spatial scales from global land, Northern Hemisphere extratropics, tropics, three continental regions (North America and western and eastern Eurasia), and global “dry” and “wet” land areas (as defined by their average extreme precipitation intensities). Results indicate that anthropogenic greenhouse gas influence is robustly detected in the observed intensification of extreme precipitation over the global land and most of the subregions considered, all with clear separation from natural and anthropogenic aerosol forcings. Also, the human‐induced greenhouse gas increases are found to be a dominant contributor to the observed increase in extreme precipitation intensity, which largely follows the increased moisture availability under global warming.
Plain Language Summary
Human influences have been identified in the observed intensification of extreme precipitation at global and continental scales, but quantifying the contribution of greenhouse gas increases remains challenging. Here, we isolate anthropogenic greenhouse gas impacts on the observed intensification of extreme precipitation during 1951–2015 by comparing observations with CMIP6 individual forcing experiments. Results show that greenhouse gas influences are detected over the global land, Northern Hemisphere extratropics, western and eastern Eurasia, and global “dry” and “wet” regions, which are separable from other external forcings such as solar and volcanic activities and anthropogenic aerosols. The human‐induced greenhouse gas increases are also found to explain most of the observed changes in extreme precipitation intensity, which are consistent with the increased moisture availability with warming. Our results provide the first quantitative evidence for the dominant influence of human‐made greenhouse gases on extreme precipitation increase.
Key Points
Causes of the observed intensification of extreme precipitation during 1951 to 2015 are examined using CMIP6 multimodel simulations
Results from optimal fingerprinting analyses show that the anthropogenic signals are robustly detected at hemispheric and continental scales
The observed increase in extreme precipitation is mostly attributed to anthropogenic greenhouse gas increases
Fiber-optic-based localized surface plasmon resonance (FO-LSPR) sensors with three-dimensional (3D) nanostructures have been developed. These sensors were fabricated using zinc oxide (ZnO) nanowires ...and gold nanoparticles (AuNPs) for highly sensitive plasmonic biosensing. The main achievements in the development of the biosensors include: (1) an extended sensing area, (2) light trapping effect by nanowires, and (3) a simple optical system based on an optical fiber. The 3D nanostructure was fabricated by growing the ZnO nanowires on the cross-section of optical fibers using hydrothermal synthesis and via immobilization of AuNPs on the nanowires. The proposed sensor outputted a linear response according to refractive index changes. The 3D FO-LSPR sensor exhibited an enhanced localized surface plasmon resonance response of 171% for bulk refractive index changes when compared to the two-dimensional (2D) FO-LSPR sensors where the AuNPs are fixed on optical fiber as a monolayer. In addition, the prostate-specific antigen known as a useful biomarker to diagnose prostate cancer was measured with various concentrations in 2D and 3D FO-LSPR sensors, and the limits of detection (LODs) were 2.06 and 0.51 pg/ml, respectively. When compared to the 2D nanostructure, the LOD of the sensor with 3D nanostructure was increased by 404%.
This study investigates the contribution of external forcings on global and regional ocean wave height change during 1961–2020. Historical significant wave height (Hs) produced for different CMIP6 ...external forcings and preindustrial control conditions following the Detection and Attribution Model Intercomparison Project (DAMIP) are employed. The internal variability ranges are compared with different external forcing scenario. Statistically significant linear trends in Hs computed over regional ocean basins are found to be mostly associated with anthropogenic forcings: greenhouse gas‐only (GHG) and aerosol‐only (AER) forcing. For Hs, GHG signals are robustly detected and dominant for most of the global ocean, except over North pacific and South Atlantic, where AER signals are dominant. These results are supported by multi‐model analysis for wind speed. The remarkable increase in Hs over the Arctic (22.3%) and Southern (8.2%) Ocean can be attributed to GHG induced sea‐ice depletion and larger effective fetch along with wind speed increase.
Plain Language Summary
We quantify the influence of anthropogenic forcings (greenhouse gas‐only and aerosol‐only forcing) and natural forcing to the significant wave height trends during 1961–2020 using CMIP6 individual forcing experiments. It is shown that anthropogenic influence is majorly responsible for the significant wave height changes and natural (solar and volcanic activities) forcings show limited influence. The human‐induced greenhouse gas increases are found to be the dominating factor for most of the global ocean, whereas anthropogenic aerosols are the dominating forcing for a few ocean basins, such as North Pacific and South Atlantic. The multimodel analysis for wind speed corroborates the relative dominance of signals in wave height change. In the polar ocean (Arctic and Southern Ocean), we see exceptional wave height increase compared to other regions. Sea‐ice decline associated with greenhouse gas forcing provides larger fetch for the waves to grow in polar region. Moreover, the contrasting influence of greenhouse gas and aerosol forcing to sea‐ice area and wind speed changes are shown to drive the total wave height changes.
Key Points
CMIP6/DAMIP simulations show that anthropogenic signals are robustly detected for the significant wave height (Hs) trends during 1961–2020
Greenhouse gases are the major contributor for Hs trends over the global ocean, but aerosols dominance is seen for a few regional basins
High increase in Hs over the Polar oceans is due to greenhouse gas induced sea‐ice decline, fetch enlargement and wind speed increase
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