Using observed data sets from 1979 to 2006, the relationship between El Niño Modoki and spring rainfall over south China (SC) is investigated. Of particular interest is the difference in the ...influence on spring rainfall of typical El Niño events and the recently recognized El Niño Modoki events, which are characterized by distinct warm sea surface temperature anomalies (SSTA) in the central Pacific and weaker cold anomalies in the western and eastern parts of the basin. Associated with the SSTA, anomalous ascent occurs over the central Pacific and downward flow is observed over the eastern and western Pacific. The anomalous flow is associated with anomalous convergence in the upper troposphere over the western Pacific. SC is influenced by an anomalous anticyclonic circulation with prevailing northeasterly anomalies. The convective activity in SC becomes weaker, resulting in reduced rainfall. However, the situation is different in the case of El Niño, in terms of the influence on rainfall over SC. While El Niño Modoki events are accompanied by a significant reduction in rainfall over SC, there is enhanced rainfall associated with El Niño events. Moreover, there exists a strong asymmetry in the relationship between SC spring rainfall, typical El Niño–Southern Oscillation (ENSO) and ENSO Modoki events. It appears that these relationships are only statistically significant for positive events. The asymmetric influence of positive and negative in two ENSO phenomena may explain the difference in their respective relationships with spring rainfall over SC.
Key Points
We find El Nino Modoki has a strong influence on south China spring rainfall
The influence of ENSO on SC spring rainfall is positive
There exists an asymmetry in the relation of ENSO Modoki and SC rainfall
Scientific issues relevant to interactions between aerosols and the Asian monsoon climate were discussed and evaluated at the 33rd ＂Forum of Science and Technology Frontiers＂ sponsored by the ...Department of Earth Sciences at the Chinese Academy of Sciences. Major results are summarized in this paper. The East Asian monsoon directly affects aerosol transport and provides a favorable background circulation for the occurrence and development of persistent fog-haze weather. Spatial features of aerosol transport and distribution are also influenced by the East Asian monsoon on seasonal, inter-annual, and decadal scales. High moisture levels in monsoon regions also affect aerosol optical and radiative properties. Observation analyses indicate that cloud physical properties and precipitation are significantly affected by aerosols in China with aerosols likely suppressing local light and moderate rainfall, and intensifying heavy rainfall in southeast coastal regions. However, the detailed mechanisms behind this pattern still need further exploration. The decadal variation in the East Asian monsoon strongly affects aerosol concentrations and their spatial patterns. The weakening monsoon circulation in recent decades has likely helped to increase regional aerosol concentrations. The substantial increase in Chinese air pollutants has likely decreased the temperature difference between land and sea, which favors intensification of the weakening monsoon circulation. Constructive suggestions regarding future studies on aerosols and monsoons were proposed in this forum and key uncertain issues were also discussed.
A teleconnection between the North Atlantic Ocean and the Eurasian continent is suggested by statistical and dynamical analysis of the northern summer 500 hPa geopotential height field. This ...teleconnection, termed the Atlantic-Eurasian (AEA) teleconnection, has five centers of action, in the subtropical North Atlantic Ocean, northeastern North Atlantic Ocean, Eastern Europe, the Kara Sea, and north China. The AEA index (AEAI) shows that the AEA undergoes a high degree of variability from year to year, and the AEAI has an increasing trend over the last 30 years. Our results suggest that this phenomenon is a large-scale Rossby wave train that originates in the subtropical North Atlantic Ocean. We support this conclusion by the methods of stationary wave ray tracing in non-uniform horizontal basic flow, wave activity flux calculations, and numerical models. The AEA and midlatitude circumglobal teleconnection pattern manifest distinct features at the hemispheric scale, despite the anomalies associated with them bear some similarities in the northeastern North Atlantic and Eastern Europe. Regional climate variations are strongly linked to this AEA along its path through northern Eurasia.
Sensitivity is an important parameter of molecularly imprinted electrochemical sensors, and various methods have been extensively investigated to improve this parameter. This review focuses on recent ...reports about different methods that can enhance the sensitivity of these sensors. To a great extent, the sensitivity of the molecularly imprinted sensor is limited by the number of cavities formed in a molecularly imprinted polymer on an electrode after elution. To enhance sensitivity and fabricate sensing devices, researchers employ signal amplification by labels, amplification by functional materials doped in imprinted membranes, sensitive film amplification, and other methods. Some perspectives in this research area, current problems, and challenges are also outlined.
Sensitivity is a critical issue of the performance of molecularly imprinted electrochemical sensors. This review focuses on recent reports of methods that can enhance their sensitivity. Perspectives in this research area, current problems, and challenges are also outlined. Display omitted
•Different methods for improving sensitivity of molecularly imprinted electrochemical sensors were overviewed.•Amplification strategies were discussed and divided into three categories.•Inherent advantages and limitations of these strategies for bioanalysis were discussed.•Prospects of highly sensitive molecularly imprinted electrochemical sensors were assessed.
The possible influences of two types of ENSO i.e., the canonical ENSO and ENSO Modoki (EM) on Hadley circulation (HC) during the boreal spring are investigated during 1979–2010. El Niño events are ...featured with a symmetric pattern in equatorial zonal-mean sea surface temperature anomalies (SSTA), with a maximum around the equator. In contrast, the zonal-mean SSTA associated with El Niño Modoki events shows an asymmetric structure with a maximum around 10°N. The contrasting underlying thermal structures corresponding with ENSO and EM have opposite impacts on the simultaneous HC. In El Niño years, a symmetric anomalous meridional circulation is seen, with enhanced rising around the equator and anomalous descent at about 15°N and 20°S. In contrast, an asymmetric equatorial meridional circulation is observed for El Niño Modoki years, with anomalous ascent around 10°N and descent at about 10°S and 20°N. The contrasting meridional circulation anomalies within ENSO and EM are caused by their different meridional SSTA structure. This result is theoretically explained, indicating that anomalous meridional circulation is subject to the meridional SSTA gradient. Moreover, the observed results are reproduced in numerical experiments driven by anomalous warming in the eastern and central Pacific Ocean. Thus, the authors conclude that the anomalous HC linked to ENSO and EM is induced by the accompanying meridional gradient in zonal-mean SSTA.
Making accurate predictions of chaotic dynamical systems is an essential but challenging task with many practical applications in various disciplines. However, the current dynamical methods can only ...provide short-term precise predictions, while prevailing deep learning techniques with better performances always suffer from model complexity and interpretability. Here, we propose a new dynamic-based deep learning method, namely the dynamical system deep learning (DSDL), to achieve interpretable long-term precise predictions by the combination of nonlinear dynamics theory and deep learning methods. As validated by four chaotic dynamical systems with different complexities, the DSDL framework significantly outperforms other dynamical and deep learning methods. Furthermore, the DSDL also reduces the model complexity and realizes the model transparency to make it more interpretable. We firmly believe that the DSDL framework is a promising and effective method for comprehending and predicting chaotic dynamical systems.
The twentieth century Northern Hemisphere mean surface temperature (NHT) is characterized by a multidecadal warming‐cooling‐warming pattern followed by a flat trend since about 2000 (recent warming ...hiatus). Here we demonstrate that the North Atlantic Oscillation (NAO) is implicated as a useful predictor of NHT multidecadal variability. Observational analysis shows that the NAO leads both the detrended NHT and oceanic Atlantic Multidecadal Oscillation (AMO) by 15–20 years. Theoretical analysis illuminates that the NAO precedes NHT multidecadal variability through its delayed effect on the AMO due to the large thermal inertia associated with slow oceanic processes. An NAO‐based linear model is therefore established to predict the NHT, which gives an excellent hindcast for NHT in 1971–2011 with the recent flat trend well predicted. NHT in 2012–2027 is predicted to fall slightly over the next decades, due to the recent NAO decadal weakening that temporarily offsets the anthropogenically induced warming.
Key Points
The NAO leads the DNHT by 15‐20 years in the observations
The slow oceanic processes may account for the time lead of NAO leading DNHT
A NAO‐based model is a useful predictive tool for the NHT
The purpose of this review is to summarize the research progress of PI3K/Akt signaling pathway in erythropoiesis and glycolysis. Phosphatidylinositol‑4,5‑bisphosphate 3‑kinase (PI3K) is activated by ...numerous genes and leads to protein kinase B (Akt) binding to the cell membrane, with the help of phosphoinositide‑dependent kinase, in the PI3K/Akt signal transduction pathway. Threonine and serine phosphorylation contribute to Akt translocation from the cytoplasm to the nucleus and further mediates enzymatic biological effects, including those involved in cell proliferation, apoptosis inhibition, cell migration, vesicle transport and cell cancerous transformation. As a key downstream protein of the PI3K/Akt signaling pathway, hypoxia‑inducible factor (HIF)‑1 is closely associated with the concentration of oxygen in the environment. Maintaining stable levels of HIF‑1 protein is critical under normoxic conditions; however, HIF‑1 levels quickly increase under hypoxic conditions. HIF‑1α is involved in the acute hypoxic response associated with erythropoietin, whereas HIF‑2α is associated with the response to chronic hypoxia. Furthermore, PI3K/Akt can reduce the synthesis of glycogen and increase glycolysis. Inhibition of glycogen synthase kinase 3β activity by phosphorylation of its N‑terminal serine increases accumulation of cyclin D1, which promotes the cell cycle and improves cell proliferation through the PI3K/Akt signaling pathway. The PI3K/Akt signaling pathway is closely associated with a variety of enzymatic biological effects and glucose metabolism.
China has been experiencing increased concentrations of aerosols, commonly attributed to the large increases in emissions associated with the rapid economic development. We show by using a chemical ...transport model driven by the assimilated meteorological fields that the observed decadal‐scale weakening of the East Asian summer monsoon also contributed to the increases in aerosols in China. We find that the simulated aerosol concentrations have strong negative correlations with the strength of the East Asian Summer monsoon. Accounting for sulfate, nitrate, ammonium, black carbon, and organic carbon aerosols, the summer surface‐layer PM2.5 concentration averaged over eastern China (110°–125°E, 20°–45°N) can be 17.7% higher in the weakest monsoon years than in the strongest monsoon years. The weakening of the East Asian Summer monsoon increases aerosol concentrations mainly by the changes in atmospheric circulation (the convergence of air pollutants) in eastern China.
Key Points
The weakening of the East Asian summer monsoon increases aerosol in China
Monsoon circulation is the dominant factor that explains the increase in aerosol
Climate change increases aerosol concentrations in China
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