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Temperature correlation network has been commonly used in climate monitoring, diagnosing and prediction using reanalysis data, however its application in the network analysis of climate dynamical models hasn't been deeply studied. We construct a temperature correlation network based on near-surface 2m air temperature of four climate models by comparing their capability of properly capturing the structural characteristics of the temperature networks, and further conduct a comparative analysis of the topological differences among different models. The features of temperature correlation networks varied significantly among the four models, in which the ECMWF-SYSTEM5 model network has the highest connectivity among the four models, while the NCEP_CFS2 model has the lowest one. It is also revealed that the model with higher connectivity normally has a stronger correlation between the nodes of the air temperature correlation network, which is likely attributed to the model's stronger teleconnection, regional consistency and smaller standard deviation between predicted temperature series of most two grid points. It is also implied that the model's prediction skills have a probable relationship with the network structure. For each model, the 1-month lead prediction has the highest prediction skill corresponding to the model having the connectivity close to the observation. With the increase of prediction lead times, connectivity bias has a quick rise, and the prediction skill has an obvious decrease. However, for different models at the same prediction lead time, it is not the case that the larger the connectivity deviation the lower the prediction skill, for example, the ECMWF_SYSTEM5 model has the highest prediction skill and the largest connectivity deviation, we find that the ECMWF_SYSTEM5 model network possesses significantly higher connectivity and more distinctive small-world characteristics, which implies a stable network structure helps to improve the prediction skills of the model. Therefore, this study can deepen our understanding of climate models and provide guidance for improving the ability of models to properly simulate climate features. [ABSTRACT FROM AUTHOR]

Summer precipitation prediction in China is important to society and economic development, but still a challenging issue in current meteorological studies, due to the uncertainty of the climate system. This paper developed a weighted integration method founded on dynamic-statistic prediction methods. The advantages and disadvantages of station-based and grid-based integration on summer precipitation prediction, along with the underlying reasons, are respectively analyzed by calculating the anomaly correlation coefficients (ACC), prediction score (PS), and root-mean-square errors (RMSE). The main manifestations indicated that 1) The weighted integration method can provide better skill of summer rainfall prediction in China than the single dynamic-statistic combined prediction method; 2) For the station-based integration, the 10-year ACC mean of summer precipitation prediction is 0.098–0.106, passing the 90% significance level, which is also obviously higher than that of the grid-based integration. The station-based integration has a higher symbol consistency ratio (SCR) than the grid-based integration, and the probability distribution of anomaly percentiles of station-based integration is closer to the observation, which causes the corresponding PS score to be 69.2–70.0 and higher than the grid-based integration. The independent sample validation of 2020 and 2021 further confirmed that station-based integration had a higher ACC than grid-based integration. It is indicated that station-based integration may have better performance in improving the accuracy of the summer precipitation prediction in China, which needs to be deeply considered in the scientific study and real prediction issues. [ABSTRACT FROM AUTHOR]

This study used observed rainfall, ERA5 reanalysis, and CMIP6 model datasets to investigate the interdecadal variation and underlying mechanism of persistent heavy rainfall (PHR) over the Huaihe River Basin (HRB) in China during July–August, and to examine the role of the Atlantic Multidecadal Oscillation (AMO) in modulating such rainfall. The results indicate that PHR over the HRB exhibited a marked interdecadal variation. The interdecadal increase in PHR was found attributable primarily to interdecadal enhancement of ascending motion, which might have been due to external forcing by the AMO. The AMO can trigger upper-tropospheric mid–high-latitude Rossby wave trains that can lead to an upper-tropospheric anticyclone and a lower-tropospheric cyclone configuration over the HRB. Increased warm advection and greater transport of water vapor from lower latitudes, caused by enhanced southerlies in the middle–lower troposphere over the HRB, can also lead to enhanced ascending motion over the HRB. Meanwhile, an anomalous cyclone over northeastern China triggered by AMO can transport cold air from higher latitudes to the HRB, boosting convection and promoting the development and duration of PHR. By affecting sea surface temperature in the western North Pacific Ocean, the AMO can also indirectly cause a meridional teleconnection pattern in the lower troposphere, which increases the transport of water vapor to the HRB. Numerical model experiments can reproduce both the interdecadal variations in PHR and the mechanisms of the influence of the AMO on PHR, providing a reliable foundation for understanding and forecasting PHR over the HRB. [ABSTRACT FROM AUTHOR]

Thermal layout optimization problems are common in integrated circuit design, where a large number of electronic components are placed on the layout, and a low temperature (i.e., high efficiency) is achieved by optimizing the positions of the electronic components. The operating temperature value of the layout is obtained by measuring the temperature field from the expensive simulation. Based on this, the thermal layout optimization problem can be viewed as an expensive combinatorial optimization problem. In order to reduce the evaluation cost, surrogate models have been widely used to replace the expensive simulations in the optimization process. However, facing the discrete decision space in thermal layout problems, generic surrogate models have large prediction errors, leading to a wrong guidance of the optimization direction. In this work, the layout scheme and its temperature field are represented by images whose relation can be well approximated by a deep neural network. Therefore, we propose an online deep surrogate-assisted optimization algorithm for thermal layout optimization. First, the iterative local search is developed to explore the discrete decision space to generate new layout schemes. Then, we design a deep neural network to build an image-to-image mapping model between the layout and the temperature field as the approximated evaluation. The operating temperature of the layout can be measured by the temperature field predicted by the mapping model. Finally, a segmented fusion model management strategy is proposed to online updates the parameters of the network. The experimental results on three kinds of layout datasets demonstrate the effectiveness of our proposed algorithm, especially when the required computational budget is limited. [ABSTRACT FROM AUTHOR]

Recovering the global accurate complex physics field from limited sensors is critical to the measurement and control of the engineering system. General reconstruction methods for recovering the field, especially the deep learning with more parameters and better representational ability, usually require large amounts of labeled data which is unaffordable in practice. To solve the problem, this paper proposes uncertainty guided ensemble self-training (UGE-ST), using plentiful unlabeled data to improve reconstruction performance and reduce the required labeled data. A novel self-training framework with the ensemble teacher and pre-training student designed to improve the accuracy of the pseudo-label and remedy the impact of noise is first proposed. On the other hand, uncertainty guided learning is proposed to encourage the model to focus on the highly confident regions of pseudo-labels and mitigate the effects of wrong pseudo-labeling in self-training, improving the performance of the reconstruction model. Experiments including the airfoil velocity and pressure field reconstruction and the electronic components' temperature field reconstruction indicate that our UGE-ST can save up to 90% of the data with the same accuracy as supervised learning. [ABSTRACT FROM AUTHOR]

Assessing the capability of sub-seasonal rainfall forecast of dynamic model and proposing correction method is quite an important topic in current climate research field. From the perspective of rainfall amount, rainy days and rainfall-belt evolution, the sub-seasonal forecast ability of the European Centre for Medium-Range Weather Forecasts (ECMWF) model for the main rainy-season rainfall in eastern China is evaluated. Evaluation results show that the forecast biases increase gradually with the increase of forecast lead time, characterized by the predicted rainfall amount being obviously higher and the rainy days being much longer than observation. In order to reduce the forecast biases of sub-seasonal rainfall forecast of ECMWF model, the rainy day-based correction (RDC) method is proposed in this study. Cross validation results indicate that RDC method can modify the number of rainy days forecast of ECMWF model with the SCC of rainy days increasing by 12.96% ~ 18.62%, and the RMSE decreasing by 56.49% ~ 63.78%. The problem of maximum continuous rainy days being too long in the model forecast can be also improved. Meanwhile, the spatial correlation coefficient (SCC) of rainfall amount forecast of the ECMWF model with the observation weakly increases by 0.61% ~ 1.56% and the root mean square error (RMSE) decreases by 3.50% ~ 7.60% after the RDC treatment. Therefore, RDC method presents a good performance on improving the sub-seasonal forecast of rainy days, and maximum continuous rainy days, which can be further applied in other models' sub-seasonal forecast error correction. [ABSTRACT FROM AUTHOR]

Convolutional neural networks (CNNs) have successfully demonstrated their powerful predictive performance in a variety of tasks. However, it remains a challenge to estimate the uncertainty of these predictions simply and accurately. Deep Ensemble is widely considered the state-of-the-art method which can estimate the uncertainty accurately, but it is expensive to train and test. MC-Dropout is another popular method that is less costly but lacks the diversity of predictions resulting in less accurate uncertainty estimates. To combine the benefits of both, we introduce a ReLU-Based Uncertainty Estimation (RBUE) method. Instead of using the randomness of the Dropout module during the test phase (MC-Dropout) or using the randomness of the initial weights of CNNs (Deep Ensemble), RBUE uses the randomness of activation function to obtain diverse outputs in the testing phase to estimate uncertainty. Under the method, we propose strategy MC-DropReLU and develop strategy MC-RReLU. The uniform distribution of the activation function's position in CNNs allows the randomness to be well transferred to the output results and gives a more diverse output, thus improving the accuracy of the uncertainty estimation. Moreover, our method is simple to implement and does not need to modify the existing model. We experimentally validate the RBUE on three widely used datasets, CIFAR10, CIFAR100, and TinyImageNet. The experiments demonstrate that our method has competitive performance but is more favorable in training time. [ABSTRACT FROM AUTHOR]

The temperature field reconstruction of heat source systems (TFR-HSS) with limited monitoring sensors in thermal management plays an important role in the real-time health detection systems of electronic equipment in engineering. However, prior methods with common interpolations usually cannot provide accurate reconstruction performance as required. In addition, no public dataset exists for the wide research of reconstruction methods to further boost reconstruction performance and engineering applications. To overcome this problem, this work develops a machine learning surrogate modeling benchmark for the TFR-HSS task. First, the TFR-HSS task is mathematically modeled from a real-world engineering problem, and four types of computational modelings are constructed to transform the problem into discrete mapping forms. Then, this work proposes a set of machine learning surrogate modeling methods, including general machine learning methods and deep learning methods, to advance the state-of-the-art methods over temperature field reconstruction. More importantly, this work develops a novel benchmark dataset, namely the temperature field reconstruction dataset (TFRD), to evaluate these machine learning surrogate modeling methods for the TFR-HSS task. Finally, a performance analysis of typical methods is given on the TFRD, which can serve as the baseline results on this benchmark. [ABSTRACT FROM AUTHOR]

Enrofloxacin (ENR) is a widely used veterinary fluoroquinolone antibiotic and is frequently detected in water environments. The degradation of ENR was examined utilizing molecular oxygen mediation using nanometer zero-valent copper (nZVC) as the catalyst in this work. The dosage of nZVC, initial pH, and reaction temperature were investigated as contributing factors to ENR degradation. The effects of Cl−, NO3−, SO42−, and humic acid on the degradation of ENR were investigated. The actual effects were evaluated using natural water. The reactive oxygen species (ROS) that participated in the reaction were identified, their generation mechanisms were elucidated, and the effects on ENR degradation were assessed. More emphasis was given to exploring ENR degradation and transformation pathways via analyses of HPLC-TOF–MS. Data showed that at 35 ℃, with an initial pH of 3 and exposed to air, an nZVC dose of 0.5 g·L−1 degraded ENR by 99.51% dramatically. HO• radicals were identified as the dominant ROS, and conversions among Cu0, Cu+, and Cu2+ played crucial roles in the generation of ROS. The destruction mechanism of ENR was speculated based on analyses of HPLC-TOF–MS results as the transformation of the piperazine ring into an oxidized state with a -COOH substitution with HO•, which caused ENR to be mineralized and converted into CO2, H2O, and NO 3 - . The ECOSAR program has been used to evaluate the toxicity of ENR and its degradation products, and oxidative degradation of nZVC significantly reduced its toxicity and increased its biodegradability. This research proposes a capable and practical method for removing ENR from water. [ABSTRACT FROM AUTHOR]

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This work aims to investigate the gasification characteristics of oily sludge in CO2 atmosphere. In this study, the gasification characteristics of two typical oily sludge (SSOS and SLOS) in CO2 atmosphere were compared and studied by fixed bed experiment and thermogravimetric analysis system. TG-DTG analysis results showed that the reaction was completed at 600 °C, while the termination temperature of SLOS was 650 °C. The thermal conversion of oil phase (excluding asphaltene) of SSOS and SLOS both maintained between 200 and 550 °C, showing high similarity. In kinetics analysis part, the average Ea of SSOS and SLOS was about 90 kJ mol−1 and 110 kJ mol−1, respectively, which means the gasification reaction difficulty of SSOS was slightly lower than SLOS. The gasification products are mainly composed of H2 and CO. For CO, as the temperature exceeded 800 °C, the output surged, and the H2 output only increased slightly. The effect of gasification agent was much less than that of temperature. When R exceeded 1, the dosage of CO2 has little effect on the output of gas products. [ABSTRACT FROM AUTHOR]

This paper investigates the causes for the interdecadal change in the relationships between early and late summer precipitation over South China (SC). It is found that the correlations of the precipitation over SC between June and August shift from weak positive in 1979–1995 to significantly negative in 1996–2019. Further analysis demonstrates that the distinct evolution of sea surface temperature (SST) pattern between the two periods accounts for the interdecadal variations of their relationships. Although the warming of the tropical western Indian Ocean (WIO) in June favors increasing precipitation over the SC via enhancing the Northwest Pacific Subtropical High (NWPSH) during the whole period, the associated SST anomalies in August are rather different between the two periods. Specifically, the WIO warming in June corresponds to slightly positive anomalies over the tropical central-eastern Pacific in August during the 1979–1995, which has weak impact on the NWPSH and results in a weak precipitation correlation between June and August. However, the WIO warming in June corresponds to La Niña's rapid development in August during the 1996–2019, which favors the enhancement of the NWPSH via increasing the regional Hadley circulation. Due to the climatologically northward movement of NWPSH from June to August, the enhanced NWPSH in August acts to decrease the precipitation over SC, causing a significantly negative correlation between precipitation in June and August. Overall, the distinct evolution of tropical SST pattern is the key factor inducing the change of the relationships between June and August precipitation in the two periods. [ABSTRACT FROM AUTHOR]

In this paper, pyrolysis treatment was carried out with the tank bottom sludge of Liaohe Oilfield (LSOS) as the treatment object. Pyrolysis oil has the highest output of only 6% and the main components are gasoline and light diesel. Syngas which was the main form of energy recovery was mainly composed of CO/CO2, CH4, C2H4, etc. Temperature is the most important factor affecting energy recovery, and high-temperature environments have a positive impact on the cracking of macromolecular hydrocarbons. Increasing the temperature had a significant effect on improving the efficiency of energy recovery, which is beneficial to the recovery of energy in the form of gaseous and liquid oil. The content of organic matter in char greatly reduced, which was reflected in the significant reduction in C/H content. Part of the S/N compounds migrated and transformed, mixed into gas and liquid oil while heavy metals were enriched in char. The thermogravimetric method was carried out for the study on the pyrolysis behavior of LSOS. Starink method, KAS method and FWO method were used to calculate the kinetic parameters. The activation energy range and the average activation energy calculated by the three methods all showed high similarity, which were 61.75–237.33 kJ·mol−1, 52.58–205.63 kJ·mol−1and 59.35–207.54 kJ·mol−1 and the average values were 122.19 kJ·mol−1, 106.64 kJ·mol−1 and 112.13 kJ·mol−1, respectively. [ABSTRACT FROM AUTHOR]

World cultural landscape heritage (WCLH), recognized as a combination of cultural relics and natural landscapes with outstanding significance and universal value, is unique in terms of its differentiation from the deliberate human creativity of general cultural heritage and the "deartificialization" of natural heritage. To date, the management of WCLH has become increasingly standardized. However, with the prevalence of heritage resource development activities such as heritage tourism, the phenomenon of "urbanization", "commercialization", "artificialization" and other issues have gradually emerged in WCLH sites. Thus, the management issues of WCLH have become increasingly serious, leading to intense concerns about the unsustainable development of WCLH. Drawing inspirations from management effectiveness (ME) evaluation research of protected areas and acknowledging the uniqueness of WCLH, this study constructs a WCLH ME evaluation system consisting of four general criteria (management foundation, management system, management measures and management performance), 16 factors and 34 indicators. The evaluation system is applied and verified through an empirical study of five existing WCLH sites in China. The empirical results show that the ME of Chinese WCLH is at a "good" level. Specifically, the management of Chinese WCLH is overall impressive in indicators of management planning, heritage protection performance and economic performance but shows deficiency in indicators of protection fees, management infrastructure, management assessment, management institution, social performance, etc. Finally, this study discusses the management issues of respective heritage sites to provide suggestions and inspirations for the development, protection and management of the sites and other cultural landscapes in China and even the world. [ABSTRACT FROM AUTHOR]

Southwest China (SWC) is located in the transition zone affected by the East Asia summer monsoons, India monsoon, and the Tibetan Plateau thermal activity. SWC is also an important hub for water vapor transport in the Asia–Pacific (AP) region. Here we study the dynamical and spatiotemporal characteristics of extreme rainfall events in AP by a synchronization network approach, providing insights for understanding of the relevant synchronization mechanisms of extreme rainfall between the SWC and AP. It is found that the probability of significant synchronization rainfall events between SWC and AP as a function of distance changes from a power-law decay behavior to a teleconnection one at around 2000 km. Specifically, the SWC—the middle and lower reaches of the Yangtze River—Japan band (SYJ) is an important teleconnection pattern of extreme rainfall in AP region. This SYJ teleconnection pattern is associated with the water vapor flux convergence along the main water vapor transport route from the low latitude ocean. Moreover, we find that the inter-annual variation of the SYJ teleconnections index can reflect the evolution of synchronization rainfall features from SWC to Japan, which could be useful for operational climate monitoring and prediction. It is also found that the SYJ index is strongly correlated with the sea surface temperature anomalies (SSTA) over the North Indian Ocean and the Western Pacific. The warm Indian Ocean and Western Pacific SST can motivate the transfer of water vapor from SWC to Japan, yielding the synchronization of extreme rainfall along the SYJ band. [ABSTRACT FROM AUTHOR]

Quantifying predictive uncertainty in deep neural networks is a challenging and yet unsolved problem. Existing quantification approaches can be categorized into two lines. Bayesian methods provide a complete uncertainty quantification theory but are often not scalable to large-scale models. Along another line, non-Bayesian methods have good scalability and can quantify uncertainty with high quality. The most remarkable idea in this line is Deep Ensemble, but it is limited in practice due to its expensive computational cost. Thus, we propose HatchEnsemble to improve the efficiency and practicality of Deep Ensemble. The main idea is to use function-preserving transformations, ensuring HatchNets to inherit the knowledge learned by a single model called SeedNet. This process is called hatching, and HatchNet can be obtained by continuously widening the SeedNet. Based on our method, two different hatches are proposed, respectively, for ensembling the same and different architecture networks. To ensure the diversity of models, we also add random noises to parameters during hatching. Experiments on both clean and corrupted datasets show that HatchEnsemble can give a competitive prediction performance and better-calibrated uncertainty quantification in a shorter time compared with baselines. [ABSTRACT FROM AUTHOR]

Conform and non-conformal contact problem in the face of piezoelectric motors can be hard to grasp, especially both the friction drive and wear lifespan are considered. Flowing the classical contact issue, an elastic brittle flat punch as the driving tip of the stator for piezoelectric devices is chosen and the contact behaviour under elliptical ultrasonic vibration is investigated using finite element method. A limited stress analysis is conducted after the quasi-static contact of the driving tip and the slider of the linear ultrasonic motors. After the analytical traces and experimental test on the fracture failure induced by the stress actions, the failure criteria of the elastic brittle driving tip are discussed. Results show that this quasi-static method can be applied to the complex contact analysis of an elliptical vibration device, and the failure characteristics induced by stress and strain can be obtained by FEM simulation and experiment verification. The pre-fracture stress map provides an important basis for the design of the geometrical mutation edge (e.g. edge fillet) of the elastic brittle punch and the composite structure for strength capacity. The failure analysis of brittle materials under ultrasonic vibration requires attention on quasi-brittle and quasi-plastic strength criterions. This study focus on determination of the contact stresses and the limited states during the elliptical vibration of a stator tip against slider. It also is important for the analysis on failure modes of frictional materials of ultrasonic devices, fretting wear of high-frequency connecting parts and machining process assisted with ultrasonic vibration. [ABSTRACT FROM AUTHOR]

The thermal issue is of great importance during the layout design of heat source components in systems engineering, especially for high functional-density products. Thermal analysis requires complex simulation, which leads to an unaffordable computational burden to layout optimization as it iteratively evaluates different schemes. Surrogate modeling is an effective method for alleviating computation complexity. However, the temperature field prediction (TFP) with complex heat source layout (HSL) input is an ultra-high dimensional nonlinear regression problem, which brings great difficulty to traditional regression models. The deep neural network (DNN) regression method is a feasible way for its good approximation performance. However, it faces great challenges in data preparation for sample diversity and uniformity in the layout space with physical constraints and proper DNN model selection and training for good generality, which necessitates the efforts of layout designers and DNN experts. To advance this cross-domain research, this paper proposes a DNN-based HSL-TFP surrogate modeling task benchmark. With consideration for engineering applicability, sample generation, dataset evaluation, DNN model, and surrogate performance metrics are thoroughly investigated. Experiments are conducted with ten representative state-of-the-art DNN models. A detailed discussion on baseline results is provided, and future prospects are analyzed for DNN-based HSL-TFP tasks. [ABSTRACT FROM AUTHOR]

Recently, more attention has been focused on the surrogate model using deep learning methods due to its powerful representational ability. However, it is usually challenging to obtain sufficient labeled samples for effective training because of the time-consuming numerical calculation, especially for the temperature field prediction of heat source layout (HSL-TFP). This work develops a novel and effective training method to overcome this problem for the deep surrogate model in HSL-TFP. First, the prediction of temperature field is modeled as an image-to-image regression problem, and the feature pyramid network (FPN) is chosen as the backbone of the deep network. Then, considering the inter-sample difference and the limited number of training samples, pairwise temperature field difference is utilized as data augmentation to train the surrogate model. Finally, deep transfer learning is introduced to take advantage of the valuable information from similar tasks and accelerate learning among different HSL-TFP problems. Experiments employing physic simulation data are conducted to validate the effectiveness of the proposed method. The results demonstrate that the proposed methods have significantly improved the prediction precision of the deep surrogate model with a small sample. [ABSTRACT FROM AUTHOR]

The addition of effective additives can effectively improve the pyrolysis performance of oil sludge (OS) and have a great potential to reduce pyrolysis costs. In the present study, co-pyrolysis performance of OS with different proportions of additives at a heating rate of 10°C/min was conducted in a thermal analyzer. Walnut shell, Fe2O3, K2CO3, PVC and the pyrolysis char produced from OS at the final pyrolysis temperature of 700°C were selected as the additives. TG results showed that the OS pyrolysis with and without additives can be divided into five reaction stages, which include volatilization of free water, the escape of light components, the cleavage of heavy components, carbon decomposition and inorganic minerals decomposition. The addition of additives decreased the maximum weight loss rate when the blending ratio was 5 wt% during OS pyrolysis. Kinetic analysis revealed that the overall activation energy of pyrolysis reaction was lower during pyrolysis of OS with the addition of walnut shells and pyrolysis char. The activation energy of three main reaction stages all decreased during co-pyrolysis of OS with K2CO3 and PVC. [ABSTRACT FROM AUTHOR]

An extremely heavy snowfall event occurred in early winter (November–December) 2018 over the northeast of Tibetan Plateau (NTP), with snowfall amounts ranking the highest since 1961. It is necessary to better understand the causes and reveal the physical mechanism of this extreme snowfall event. In this article, the features of this extreme snowfall event and its possible linkage with atmospheric circulation anomalies, and sea surface temperature (SST) anomaly effects are analyzed. The results show that in early winter 2018, (1) there was a similar Eurasian teleconnection (EU) pattern in the mid-latitudes with a periodic strengthening of the Siberian High, which favored northern cold airflow into the NTP, providing the suitable temperature conditions for snowfall. (2) Low-latitude meridional and mid-latitude zonal water vapor transport were both significantly greater than normal, causing much more water vapor flow than normal into the NTP region through the western and southern boundaries, leading to the second highest net water vapor input since 1961 and creating sufficient continuous water vapor conditions for extreme snowfall. (3) The baroclinicity and the instability of the atmospheric circulation, accompanied by abnormal cold and warm advection and vertical movement over the NTP, provided the dynamic atmospheric conditions for the snowfall event. (4) Under the background of warm El Niño Southern Oscillation (ENSO) event and the positive phase of the Tropical Indian Ocean dipole (IOD) SST, the EU pattern initiated by the tele-influence of IOD mode dominated the midlatitude region across Eurasia continent. The positive anomalies of EU teleconnection over western Asia guided the heavy water vapor flow into the NTP through the western and southern boundaries, respectively. In addition, the effects of ENSO/IOD caused the northern Indian Ocean and northwest Pacific to be dominated by anticyclones, creating more northward water vapor transport from the tropical region. Accordingly, sufficient water vapor flowed into the NTP along the eastern edge of the Tibetan Plateau, providing the moisture conditions for the severe snowfall event. [ABSTRACT FROM AUTHOR]

This article uses wave activity flux and sea surface temperature (SST) to explore the mechanism of EAP-EU combined impact on summer rainfall in North Asia (NA). EAP and EU teleconnections can be divided into four categories of configuration according to their anomaly phase features. The category I (II) configurations cause rainfall in the Urals and the Okhotsk Sea and the region from Northeast China to Japan being less (more), the Lake Baikal to the Okhotsk Sea being more (less), which leads to the summer rainfall in NA mainly presenting the "− + −" ("+ − +") a tripole wavelike structure. Category I (II) configurations also show the West-East reverse anomalies of summer rainfall in northern NA and the North-South opposite anomalies in eastern NA. The EAP and EU teleconnections have an obvious correlation with the ENSO-like pattern of SST anomalies over the tropical Pacific. When warm ENSO is in the development phase, it is conducive to stimulate Rossby waves propagating eastward from the North Atlantic Ocean via the PNA teleconnection, forming the EU teleconnection across the Eurasia continent. Meanwhile, the warm summer SSTA anomalies over tropical east Pacific and IMC are conducive to the local thermal convective over Indo-Pacific warm pool and motivate the EAP teleconnection, propagating northward to mid-high latitude region. EAP and the EU teleconnections overlapped with each other, form the tripole atmospheric structure in NA, and produce relevant rainfall anomaly patterns. For the category IV of EAP-EU configuration, the warm SST anomalies in the equatorial region gradually weaken from previous winter to summer. Weak tropical east Pacific SST anomalies are conducive to excite the EU teleconnection with different wave train features against the category II, presenting a strong positive anomaly center over the Ural mountain and Baikal lake. This positive center connected with the EAP caused positive anomalies over FER resulting in the dipole pattern of atmospheric and rainfall anomalies in the summer season. The condition is opposite for the category III (I) configuration against that of category IV (II). It is also found that the influence on EAP-EU configuration caused by ENSO-like pattern of SST anomalies over the tropical Pacific has an obvious asymmetric feature that category II (I) configuration relevant SST forcing is much significant than that of category IV(III) configuration. [ABSTRACT FROM AUTHOR]

The East Asia-Pacific (EAP) and Eurasian (EU) teleconnections are independent of each other on the seasonal timescale (with a correlation coefficient of only 0.03). But they may occur concurrently with consistent or opposite phases. This paper investigates their synergistic effect on the summer precipitation in North Asia. Based on the signs/phases of EAP and EU indices, the EAP and EU teleconnection anomalies occur in four cases: (I) positive EAP + positive EU, (II) negative EAP + negative EU, (III) positive EAP + negative EU, and (IV) negative EAP + positive EU. Further analyses show that these four configurations of EAP and EU anomalies are coherently related to different atmospheric circulations over the midlatitude Eurasian continent, leading to different summer precipitation modes in North Asia. Category I (II) corresponds to a zonal tripole structure of the geopotential height at 500 hPa over eastern Europe and the Sea of Japan, leading to less (more) than normal precipitation in eastern Europe, Japan, and the surrounding areas, and more (less) precipitation from central China to Lake Baikal and eastern Russia. Category III (IV) corresponds to a meridional dipole structure of the geopotential height at 500 hPa over North Asia, leading to more (less) precipitation in the northern North Asia and less (more) precipitation in most of the southern North Asia. Independent analysis reveals that the EAP teleconnection itself is positively correlated with the precipitation in the region between the eastern part of Lake Baikal and Okhotsk Sea, and negatively correlated with the precipitation in the region between Northeast China and Japan. Coincidently, the EU pattern and precipitation have negative correlations in Ural Mountain and Okhotsk Sea areas and positive correlations in the Lake Baikal area. The respective relations of EAP and EU with the summer precipitation in North Asia suggest that the EAP northern lobe overlapped with the EU central and eastern lobes could extend the geopotential anomalies over Lake Baikal to Russian Far East, creating an EAP-EU synergistic effect on the summer precipitation in North Asia. [ABSTRACT FROM AUTHOR]

Lodging is one of the major constraints that threaten crop productivity. Although the relationship between cell walls and straw strength has been well recognized, little relevant research has been done in wheat, particularly on the monomer composition and structural characteristics of cell wall polymers and the arrangement of vascular bundles. In this study, we systematically investigated cell wall- and straw-related traits in a range of wheat germplasm resources and culm mutants using a high-throughput platform for cell wall analysis. We found that varieties with higher breaking force exhibited higher levels of crystalline cellulose but fewer hemicellulose components than other varieties. The lignin content was not consistent with the breaking force; instead, the lignin monomer constitution might be important because a significantly higher proportion of p-hydroxyphenyl (H) and guaiacyl (G) but a lower proportion of syringyl (S) monomers of lignin was found in the higher breaking force group. The crystallinity detected by X-ray diffraction was positively correlated with breaking force, indicating that the physical/chemical properties of polysaccharides also deserve attention. In terms of anatomical characteristics, the varieties with higher breaking force had a lower number and area of smaller vascular bundles in the peripheral sclerenchyma than other varieties. These results, together with the finding of a highly significant correlation between stem breaking force and straw fresh weight, 2nd internode width, flag leaf width and SiO2 content, should provide systematic information for breeding for lodging resistance. [ABSTRACT FROM AUTHOR]

This study investigates the changing relationship between the December North Atlantic Oscillation (NAO) and the following February East Asian trough (EAT) throughout the past 60 years. We found that the relationship between the December NAO and the following February EAT is significantly enhanced after the late 1980s compared with the period before the late 1980s. The changing relationship mainly results from the enhanced relationship between the December NAO and the following February North Atlantic mid-latitudes' sea surface temperature (SST) anomalies (NAMA) during the same period. During the period after the late 1980s, the persistent positive (negative) NAO pattern from December to the following January contributes to a positive (negative) NAMA, which reaches its maximum magnitude in the following February and excites an anomalous wave train along the North Atlantic and northern Eurasia, and significantly impacts the EAT. During the period before the late 1980s, the positive (negative) NAO pattern during December cannot persist into the following January, and the related positive (negative) NAMA is insignificant during the following February, causing the response of the simultaneous EAT to be insignificant as well. Moreover, there exists a significant impact of the December NAO on the December-January NAMA after the late 1980s, while the December-January NAMA is relatively less affected by the December NAO before the late 1980s. As a result, the simultaneous response of the atmospheric circulation anomalies to the December-January NAMA are evident before the late 1980s, and the positive (negative) NAMA can excite an anomalous wave train along the North Atlantic and northern Eurasia and significantly deepen (shallow) the downstream EAT. By contrast, after involving a feature of atmosphere forcing of SST, the simultaneous feedback of the December-January NAMA on EAT is significantly decreased after the 1980s. [ABSTRACT FROM AUTHOR]

The anomalous characteristics of summer precipitation and atmospheric circulation in the East Asia-West Pacific Region (EA-WP) associated with the co-action of East Asia/Pacific teleconnection-Silk Road teleconnection (EAP-SR) are investigated in this study. The compositions of EAP-SR phase anomalies can be expressed as pattern I (+ +), pattern II (+ −), pattern III (− −), and pattern IV (− +) using EAP and SR indices. It is found that the spatial distribution of summer precipitation anomalies in EA-WP corresponding to pattern I (III) shows a tripole structure in the meridional direction and a zonal dipole structure in the subtropical region, while pattern II (IV) presents a tripole pattern in meridional direction with compressed and continuous anomalies in the zonal direction over the subtropical region. The similar meridional and zonal structures are also found in the geopotential height anomalies at 500-hPa, as well as wind anomalies and moisture convergence at 850-hPa. Finally, a schematic mechanism for the EAP-SR co-action upon the summer precipitation in EA-WP is built: (1) Pattern I (III) exhibits that the negative (positive) sea surface temperature (SST) anomalies over tropical East Pacific may cause the enhanced (weakened) convective activity dominating the West Pacific, trigger the positive (negative) EAP teleconnection and produce more (less) precipitation. Besides, the negative (positive) SST anomalies over the Indonesia Maritime Continent (IMC) may further weaken (strengthen) anomalous downward (upward) motion over the South China Sea (SCS), cause negative (positive) geopotential height anomalies at the middle troposphere and surrounding regions through the function of the tropical Hadley circulation. Then the negative (positive) geopotential height anomalies could motivate the positive (negative) EAP teleconnection through the northward propagation of wave-activity perturbation. Meanwhile, a positive (negative) geopotential height anomalous pattern over Eastern Europe motivates a Rossby wave train propagation from Western Europe to west-central Asia. This circumstance can cause suppressed (enhanced) convection and less (more) precipitation over northwestern India and Pakistan, which could strengthen the negative (positive) geopotential height and positive (negative) vorticity anomalies over central East Asia, resulting in a negative (positive) SR teleconnection along the Asian jet stream. A positive (negative) lobe over the Korean Peninsula and Japan corresponding to SR overlaps with a positive (negative) lobe of EAP, which strengthens the anomalous phase contrast on both sides of 120°E. Accordingly, summer precipitation anomalies in EA-WP exhibit the meridional tripole pattern and the zonal dipole pattern. (2) Pattern II (IV) indicates that the normal SST anomalies over the tropical East Pacific cause the weak tele-impact on the tropical West Pacific, while the positive (negative) SST anomalies over the IMC will lead to a negative (positive) lobe of EAP over the subtropical region. This circumstance can weaken the positive (negative) lobe of SR over subtropical region, causing compressed and continuous negative (positive) anomalies of 500-hPa geopotential height and positive (negative) surface precipitation anomalies from central East China to Japan. [ABSTRACT FROM AUTHOR]

Considering the possible lag of the impact of the winter Arctic oscillation (AO) on the subsequent summer climate anomalies over East Asia and that the relationship between them may differ during different periods, the non-stationary relationship between these systems and the corresponding mechanism of connection are investigated in this study. A regime shift of the winter AO index was detected around 1988, with mean AO indices of −0.69 and 0.10 for 1958-1987 and 1988-2014, respectively, and their differences passed the 99% confidence level. After the regime shift and especially since the early 1990s, negative (positive) winter AO indices corresponds with positive (negative) height anomalies over central East Asia (CEA) during the following summer. Meanwhile, the westerly jet stream tends to be northward (southward) and the East Asian summer monsoon (EASM) is strong (weak), which contributes to the warm (cold) anomalies over central China and the significantly enhanced (reduced) rainfall over northeast China. After the early 1990s, the enhanced connection of the winter AO and the following summer height anomalies over CEA is largely due to the enhanced connection of the winter AO and the following Indian summer monsoon (ISM) rainfall during the same period. The negative (positive) winter AO favors increasing (decreasing) rainfall over the ISM region, which triggers a positive (negative) circumglobal teleconnection (CGT), and results in significantly positive (negative) height anomalies over CEA. One way the winter AO could influence the following ISM rainfall is that the negative (positive) winter AO memories will be maintained by the positive (negative) sea surface temperature (SST) anomalies over the tropical Atlantic of the following summer, which are responsible for the La Niña (El Niño) developing phase and increases (decreases) the ISM rainfall. [ABSTRACT FROM AUTHOR]

Based on summer precipitation hindcasts for 1991-2013 produced by the Beijing Climate Center Climate System Model (BCC_CSM), the relationship between precipitation prediction error in northeastern China (NEC) and global sea surface temperature is analyzed, and dynamic-analogue prediction is carried out to improve the summer precipitation prediction skill of BCC_CSM, through taking care of model historical analogue prediction error in the real-time output. Seven correction schemes such as the systematic bias correction, pure statistical correction, dynamic-analogue correction, and so on, are designed and compared. Independent hindcast results show that the 5-yr average anomaly correlation coefficient (ACC) of summer precipitation is respectively improved from -0.13/0.15 to 0.16/0.24 for 2009-13/1991-95 when using the equally weighted dynamic-analogue correction in the BCC_CSM prediction, which takes the arithmetical mean of the correction based on regional average error and that on grid point error. In addition, probabilistic prediction using the results from the multiple correction schemes is also performed and it leads to further improved 5-yr average prediction accuracy. [ABSTRACT FROM AUTHOR]

This paper systematically evaluates the deviations that appear in the hindcasts of the East Asian summer precipitation (EASP) decadal change in the late 1990s in two global coupled models (BCC_CGCM and BCC_CSM). The possible causes for the deviations between the model hindcasts and observations are analyzed. The results show that the hindcasts of EASP by BCC_CGCM and BCC_CSM deviate from observations, with the anomaly correlation coefficient (ACC) being -0.01 and -0.09 for the two models, respectively. The SST anomalies in North and West Pacific and the SST index values predicted by the two models also deviate from the observations, indicating that inconsistent SST fields may be the key factor leading to the deviation in the prediction of the EASP decadal shift. Thus, a dynamic-analogue scheme is proposed to correct the precipitation hindcasts by using SSTs, where SST and EASP are highly correlated, to select historical analogue cases. Cross validations show that the average ACC of the temporal-latitude distribution of the EASP between the corrected hindcasts and observations is 0.18 for BCC_CGCM and 0.02 for BCC_CSM; both are much higher than the uncorrected hindcasts. Applying the dynamic-analogue correction scheme in both models successfully improves prediction of the EASP decadal change in the late 1990s. [ABSTRACT FROM AUTHOR]

Background: MiR-126 is likely to be closely associated with the threatening disease deep venous thrombosis (DVT).Aim: This study aims to investigate the influence of aberrantly expressed miR-126 on vascular endothelial cell (VEC) apoptosis during DVT and explore how miR-126 functions in it.Methods: MiR-126 inhibition and overexpression in vivo were respectively performed with antagomir and agomir of miR-126. Using a rat traumatic femoral DVT model, VEC apoptosis and miR-126 expression were detected by TUNEL assay and qRT-PCR before thrombogenesis and at different time phases of thrombogenesis. Protein levels of MMPs, Akt, Bcl-2, Bad, and caspase-9 in vascular tissue were measured by western blotting. In vitro, miR-126 interference, and overexpression were performed on human umbilical vein endothelial cells (HUVECs) using miR-126 inhibitor and mimics. After HUVECs were pretreated with CoCl2, cell apoptosis was analyzed using flow cytometry, and RNA/protein levels of miR-126, PIK3R2, PTEN, and phosphorylated Akts were measured with qRT-PC/western blotting.Results: The apoptosis of VECs was increased by miR-126 inhibition and obviously rescued by miR-126 overexpression. PI3K/Akt signal transduction was suppressed by miR-126 inhibition and evidently enhanced by miR-126 overexpression. Consistent with these findings, the downstream proteins (Bcl-2, Bad, and cleaved caspase-9) in PI3K/Akt pathway and the MMPs were remarkably changed by inhibition or overexpression of miR-126. In vitro experiments also showed that PI3K/Akt signaling was strengthened when miR-126 expression was upregulated or inhibited when miR-126 was knockdown.Conclusion: Overexpressed miR-126 inhibits apoptosis of VECs and DVT through targeting the anti-apoptotic pathway PI3K/Akt via PIK3R2.General Significance: These findings may provide a new target for the therapy of DVT. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) is recognized as a major and increasing health problem affected older subjects in China, and clopidogrel has been widely used for treatment of CVD patients such as atherosclerosis, myocardial infarction, and myocardial ischaemia-reperfusion damage. However, the molecular mechanisms of clopidogrel for treatment of CVD are only partially understood. This study investigated the effects of clopidogrel on palmitic acid-induced damage of human vascular endothelial cells (HUVECs), and the molecular mechanisms of LncRNA HIF1A-AS1 in regulating the proliferation and apoptosis of HUVECs in vitro. We firstly established a damage model of HUVECs through palmitic acid (PA) treatment. And the effect of clopidogrel reducing PA-induced apoptosis of HUVECs was observed by the flow cytometric measurement. To further understand the molecular mechanism of clopidogrel rescues PA-induced apoptosis, we used human LncRNA PCR array to compare the LncRNA expression profile difference between clopidogrel-treated cells and control cells. The expression of LncRNA HIF 1 alpha-antisense RNA 1 (HIF1A-AS1) was significantly altered in clopidogrel-treated cells. We further proved that suppression of HIF1A-AS1 by siRNA reduce PA-induced apoptosis and promote proliferation of HUVECs. Furthermore, we also demonstrated inhibition apoptosis effect by HIF1A-AS1 is related to mitochondrial apoptosis pathway. Hence, our results suggest that clopidogrel rescues apoptosis and promotes proliferation of PA-induced damage model of HUVECs through inhibiting the mediator LncRNA HIF1A-AS1. These findings indicate that LncRNA HIF1A-AS1 may play an important role in the pathogenesis of CVD, and provide a novel molecular mechanism of clopidogrel for treatment of CVD. [ABSTRACT FROM AUTHOR]

Based on the 1983∼2011 CMAP data, the precipitation anomaly in East Asia and its nearby sea regions (hereafter called East Asia for short) demonstrates the '+−+' pattern before 1999 and the '−+−' pattern afterwards; this decadal change is contained principally in the corresponding EOF3 component. However, the NCC_CGCM forecast results are quite different, which reveal the '+−+−' pattern before 1999 and the '−+−+' pattern afterwards. Meanwhile, the probability of improving NCC_CGCM's forecast accuracy based on these key SST areas is discussed, and the dynamic-statistics combined forecast scheme is constructed for increasing the information of decadal change contained in the summer precipitation in East Asia. The independent sample forecast results indicate that this forecasting scheme can effectively modify the NCC_CGCM's decadal change information contained in the summer precipitation in East Asia (especially in the area of 30°N-55°N). The ACC is 0.25 and ACR is 61% for the forecasting result based on the V SST area, and the mean ACC is 0.03 and ACR is 51% for the seven key areas, which are better than NCC_CGCM's system error correction results (ACC is −0.01 and ACR is 49%). Besides, the modified forecast results also provide the information that the precipitation anomaly in East Asia mainly shows the '+−+' pattern before 1999 and the '−+−' pattern afterwards. [ABSTRACT FROM AUTHOR]

The regional extreme low temperature event from December 30, 2010 to February 2, 2011 was a very rare and protracted cold event with the largest integrated index ( Z) since 1979. Two meteorological factors could be responsible for this extreme winter event. First, a persistent blocking pattern existed in the mid-latitudes. This not only allowed cold air to persist in southern China but also enabled each perturbation from the west propagating around the blocking high to trigger downstream cold air intrusions from the north. Second, the consistently downward negative Arctic Oscillation (AO) was favorable for the eastward moving of Rossby waves in middle latitudes, which made the upper reaches positive center in SLP and negative center in Z500 move to East Asia. This stable and consistent situation favored the polar area cold air invasion to the mid-latitude region. Of these two factors, the blocking pattern was likely to be the direct cause, the co-effects of consistently strong downward negative AO from the stratosphere, and the corresponding eastward moving wave train in Z500 and SLP might be the prophase teleconnection culprit. [ABSTRACT FROM AUTHOR]

Under the background of global warming, summer (JJA) low temperature events in Northeast China had not occurred for about 15 yr since 1994, but one such event took place in 2009. By using the NCEP/NCAR reanalysis data, the 100-yr station temperature data at Harbin and Changchun, and the Hadley Center sea surface temperature (SST) data, this paper intends to reveal the cause, circulation background, and influencing factors of this event. Analysis of both horizontal and vertical circulations of a low-value system over Northeast China in summer 2009 during the low temperature event shows that anomalous activities of the Northeast China cold vortex (NECV) played the most direct role. A decadal cooling trend of - 0.8°C (10 yr) over 1999-2008 at Changchun and Harbin was found, which is obviously out-of-phase with the linear warming trend (0.2°C (10 yr)) over 1961-2000 for Northeast China in response to the global warming. The previous winter North Pacific polar vortex (NPPV) area index, significantly positively related to the observed summer temperatures of Harbin and Changchun, was also in a significantly declining tendency. These provide favorable decadal backgrounds for the 2009 low temperature event. Different from the average anomaly field of 500-hPa height for summer 1994-2008 in Northeast China, in the summer of 2009, the Arctic Oscillation (AO) showed a strong negative phase distribution, and significant negative height anomalies dominated Northeast Asia, Aleutian Islands, and North Atlantic. Furthermore, the negative phase of North Pacific Oscillation (NPO) in the winter of 2008 was obviously strong, and it maintained in the spring of 2009. Meanwhile, the SSTA in the equatorial eastern-central Pacific Ocean in the winter of 2008 showed a La Niña phase, but the strength of the La Niña weakened obviously in the spring of 2009. The abnormally strong activities of NECV in June and July of 2009 were related to the disturbances of stationary waves that replaced the original ultra-long waves over the North Pacific region in April and May 2009. The singular value decomposition (SVD) and harmonic analysis results suggest that the anomalous phase of NPO is an important precursor for summer temperature variations over Northeast China, and also a stable planetary-scale component that can be extracted from the atmospheric circulation in addition to the chaotic components on the synoptic scale. [ABSTRACT FROM AUTHOR]

We introduce bilayer networks in this paper to study the coupled air-sea systems. Results show that the framework of bilayer networks is powerful for studying the statistical topology structure and dynamics in the fields of ocean and atmosphere. Based on bilayer networks, the inner and cross interactions of the sea surface temperature (SST) field and the height field are displayed, and the main three-dimensional air-sea interaction pattern is identified. The formation of the main pattern can be explained by the 'gearing between the Indian and Pacific Ocean (GIP)' model; therefore, the pattern existence can be confirmed reliably. Furthermore, lead-lag analysis reveals the trigger processes of the 'GIP'. That is, the anomalies of the tropical mid-eastern Pacific Ocean SST (TMEPO-SST) appear first; then, through the Walker circulation, the 850-hPa geopotential height over the Pacific Islands responds to the anomalies of the TMEPO-SST 2 months later; finally, the tropical Indian Ocean SST (TIO-SST) responds to the anomalies of the height 1 month later through the Asian monsoon circulation. Therefore, the impacts of the TMEPO-SST to the TIO-SST show 3 months later through the air-sea interactions between the components of the main three-dimensional air-sea interaction mode. The new framework uncovers already-known as well as other novel features of the air-sea systems and general circulation. The application of complex network theory and methodology to understand the complex interactions between the oceans and the atmosphere is promising. [ABSTRACT FROM AUTHOR]

Time series of the dryness-wetness (DW) index of 531 yr (AD 1470-2000) at 42 stations in regions A (most of North China and the east of Northwest China) and B (the Yangtze-Huaihe River valley) in China are applied to investigating the historical DW characteristics over various periods of the series with a relatively stationary average value using Bernaola-Galvan (BG) algorithm. The results indicate that region A/B underwent three drought-intensive periods (DIP; 1471-1560, 1571-1640, and 1920-2000/1501-1540, 1631-1690, and 1911-1960) in the last 531 years. In the DIP of the last 130 years, the frequency of DW transition has increased in region A, but not obviously changed in region B in comparison with the other two historical DIPs. The dry period started in about 1920 in region A with severe drought events occurring from the late 1970s to the early 1980s. It lasted for about 50-70 yr in this century, and then a DW shift took place. The wet period in region B might maintain for the coming several decades. The variations of DW in region A are positively correlated with changes in temperature, but in region B, the correlation with temperature is weaker. It is found that the number of DW indices of various categories within a running window is an exponential function of the running window length. The dryness scale factor (DSF) is defined as the reciprocal of the characteristic value of the exponential distribution, and it has a band-like fluctuation distribution that is good for the detection of extreme drought (flood) clustering events. The results show that frequencies of the severe large-scale drought events that concurrently occurred in regions A and B were high in the late 12th century, the early 13th century, the early 17th century, and the late 20th century. This provides evidence for the existence of the time-clustering phenomena of droughts (floods). [ABSTRACT FROM AUTHOR]