In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in th...In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in the lower reaches of the YRV,focusing on the city of Shanghai.We found that about 1/3 of the 2022 HW days in Shanghai can be attributed to the long-term warming trend of global warming.During mid-summer of 2022,an enhanced western Pacific subtropical high(WPSH)and anomalous double blockings over the Ural Mountains and Sea of Okhotsk,respectively,were associated with the persistently anomalous high pressure over the YRV,leading to the extreme HW.The Pacific Decadal Oscillation played a major role in the anomalous blocking pattern associated with the HW at the decadal time scale.Also,the positive phase of the Atlantic Multidecadal Oscillation may have contributed to regulating the formation of the double-blocking pattern.Anomalous warming of both the warm pool of the western Pacific and tropical North Atlantic at the interannual time scale may also have favored the persistency of the double blocking and the anomalously strong WPSH.At the subseasonal time scale,the anomalously frequent phases 2-5 of the canonical northward propagating variability of boreal summer intraseasonal oscillation associated with the anomalous propagation of a weak Madden-Julian Oscillation suppressed the convection over the YRV and also contributed to the HW.Therefore,the 2022 extreme HW originated from multiscale forcing including both the climate warming trend and air-sea interaction at multiple time scales.展开更多
Using European Centre for Medium-Range Weather Forecasts Reanalysis V5(ERA5)reanalysis data,this study investigated the reconstruction effects of various climate variabilities on surface wind speed in China from 1979 ...Using European Centre for Medium-Range Weather Forecasts Reanalysis V5(ERA5)reanalysis data,this study investigated the reconstruction effects of various climate variabilities on surface wind speed in China from 1979 to 2022.The results indicated that the reconstructed annual mean wind speed and the standard deviation of the annual mean wind speed,utilizing various climate variability indices,exhibited similar spatial modes to the reanalysis data,with spatial correlation coefficients of 0.99 and 0.94,respectively.In the reconstruction of six major wind power installed capacity provinces/autonomous regions in China,the effects were notably good for Hebei and Shanxi provinces,with the correlation coefficients for the interannual regional average wind speed time series being 0.65 and 0.64,respectively.The reconstruction effects of surface wind speed differed across seasons,with spring and summer reconstructions showing the highest correlation with reanalysis data.The correlation coefficients for all seasons across most regions in China ranged between 0.4 and 0.8.Among the reconstructed seasonal wind speeds for the six provinces/autonomous regions,Shanxi Province in spring exhibited the highest correlation with the reanalysis,with a coefficient of 0.61.The large-scale climate variability indices showed good reconstruction effects on the annual mean wind speed in China,and could explain the interannual variability trends of surface wind speed in most regions of China,particularly in the main wind energy provinces/autonomous regions.展开更多
Summer precipitation over the Yangtze River basin(YRB)in 2020 experienced a strong subseasonal and synoptic fluctuation in addition to contributing to an exceptionally large seasonal mean precipitation.The cause of th...Summer precipitation over the Yangtze River basin(YRB)in 2020 experienced a strong subseasonal and synoptic fluctuation in addition to contributing to an exceptionally large seasonal mean precipitation.The cause of this higher-frequency fluctuation is examined based on observational analyses.Apart from the continuous northward movement of the climatological mei-yu rainband,the mei-yu rainbelt in the summer of 2020 experienced multiple northward and southward swings.The cause of the swings was attributed to the subseasonal variability of southerly winds to the south and northeasterly winds to the north of the YRB.In addition,synoptic-scale variability,characterized by the eastward propagation of low-level cyclonic vorticity and precipitation anomalies,was also commonplace in the summer of 2020.While the strengthening of both the subseasonal and synoptic variabilities in the summer of 2020 was attributed to the increase of the background mean moisture,the synoptic variability was greatly affected by the subseasonal rainfall variability.As a result,both the synoptic-scale and subseasonal variabilities contributed to the north-south swings of the rainbelt.The large-scale modulations by both the seasonal mean and subseasonal anomalies provide insight regarding the optimization of issuing accurate,extended-range forecasts of extreme weather events.展开更多
Combining sea level anomalies with the mean dynamic topography derived from the geoid of the EGM08 global gravity field model and the CLS01 mean sea surface height, this study examined the characteristics of global ge...Combining sea level anomalies with the mean dynamic topography derived from the geoid of the EGM08 global gravity field model and the CLS01 mean sea surface height, this study examined the characteristics of global geostrophic surface currents and the seasonal and interannual variabilities of the mean velocity of the Kuroshio （the Kuroshio source and Kuroshio extension）. The patterns of global geostrophic surface currents we derived and the actual ocean circulation are basically the same. The mean velocity of the Kuroshio source is high in winter and low in fall, and its seasonal variability accounts for 18% of its total change. The mean velocity of the Kuroshio extension is high in summer and low in winter, and its seasonal variability accounts for 25% of its total change. The interannual variabilities of the mean velocity of the Kuroshio source and Kuroshio extension are significant. The mean velocity of the Kuroshio source and ENSO index are inversely correlated. However, the relationship between the mean velocity of the Kuroshio extension and the ENSO index is not clear. Overall, the velocity of the Kuroshio increases when La Nina occurs and decreases when E1 Nino occurs.展开更多
Climatic anomalies have drawn more and more attentions not only in the worldwide scientific circle, but also in the respect of many governments in the last decade. The floods and drought occurred in China and many oth...Climatic anomalies have drawn more and more attentions not only in the worldwide scientific circle, but also in the respect of many governments in the last decade. The floods and drought occurred in China and many other countries cause severe damages and lead to the crises of grain production, water resources and energy. The sustained aridity in Africa and other Continents and the land desertization make millions of people face imperilling of starvation. All these greatly affect the long-term development of nations, societies and economics展开更多
ASCA observations of the two Type II AGNs, NGC 7314 and NGC 7582, show clear variations in the broad X-ray band (0.4-10keV) on short timescales -104s. Spectral analysis indicates that they both have an absorbed hard X...ASCA observations of the two Type II AGNs, NGC 7314 and NGC 7582, show clear variations in the broad X-ray band (0.4-10keV) on short timescales -104s. Spectral analysis indicates that they both have an absorbed hard X-ray component and an unabsorbed soft "excess" component. To clarify the origin of the latter, we made a cross-correlation analysis of the two components. The results show that, for NGC 7314, the soft X-ray variability is proportional to that of the hard X-ray component. This indicates that the active nucleus of NGC 7314 must be partially covered and so the soft emission is a "leaking" of the variable hard component. For NGC 7582, there is no detectable variability in the soft component, although there is a definite one in the hard component. This indicates that the variable nucleus of NGC 7582 must be fully blocked by absorbing matter, and the soft emission is most likely the scattered component predicted by the AGN unified model.展开更多
The variabilities of the East Asian summer monsoon arc an important research issue in China, Japan, and Korea. in this paper, progresses of recent studies on the intrascasonal, interannual, and interdecadal variations...The variabilities of the East Asian summer monsoon arc an important research issue in China, Japan, and Korea. in this paper, progresses of recent studies on the intrascasonal, interannual, and interdecadal variations of the East Asian monsoon, especially the East Asian summer monsoon, and their causes are reviewed. Particularly, studies on the effects of the ENSO cycle, the western Pacific warm pool, the Tibetan Plateau and land surface processes on the variations of the East Asian summer monsoon are systematically reviewed.展开更多
In this paper, we mainly summarize and review the progresses in recent climatological studies(by CMSR,IAP/CAS and some associated domestic and international institutions) on the interannual and interdecadal variabilit...In this paper, we mainly summarize and review the progresses in recent climatological studies(by CMSR,IAP/CAS and some associated domestic and international institutions) on the interannual and interdecadal variabilities of monsoon troughs and their impacts on tropical cyclones and typhoons(TCs) geneses over the western North Pacific Ocean. The climatological characteristics of monsoon troughs and four types of circulation patterns favorable to TCs genesis over the western North Pacific Ocean in summer and autumn are given in this paper. It is also shown in this paper that the monsoon trough over the western North Pacific Ocean has obvious interannual and interdecadal variabilities. Especially, it is revealed in this paper that the interannual and interdecadal variabilities of the monsoon trough over the western North Pacific Ocean influence the TCs genesis not only through the impact on distributions of the vorticity in the lower troposphere and the divergence in the upper troposphere, the water vapor in the mid-and lower troposphere and the vertical shear of wind fields between the upper and lower troposphere over the western North Pacific Ocean, but also through the dynamical effects of the transition between convectively coupled tropical waves and providing disturbance energy. Besides, some climatological problems associated with TCs activity over the western North Pacific Ocean that need to be studied further are also pointed out in this paper.展开更多
Linearized shallow water perturbation equations with approximation in an equatorial β plane are used to obtain the analytical solution of wave packet anomalies in the upper bounded equatorial ocean. The main results ...Linearized shallow water perturbation equations with approximation in an equatorial β plane are used to obtain the analytical solution of wave packet anomalies in the upper bounded equatorial ocean. The main results are as follows. The wave packet is a superposition of eastward travelling Kelvin waves and westward travelling Rossby waves with the slowest speed, and satisfies the boundary conditions of eastern and western coasts, respectively.The decay coefficient of this solution to the north and south sides of the equator is inversely proportional only to the phase velocity of Kelvin waves in the upper water. The oscillation frequency of the wave packet, which is also the natural frequency of the ocean, is proportional to its mode number and the phase velocity of Kelvin waves and is inversely proportional to the length of the equatorial ocean in the east-west direction. The flow anomalies of the wave packet of Mode 1 most of the time appear as zonal flows with the same direction. They reach the maximum at the center of the equatorial ocean and decay rapidly away from the equator, manifested as equatorially trapped waves. The flow anomalies of the wave packet of Mode 2 appear as the zonal flows with the same direction most of the time in half of the ocean, and are always 0 at the center of the entire ocean which indicates stagnation, while decaying away from the equator with the same speed as that of Mode 1. The spatial structure and oscillation period of the wave packet solution of Mode 1 and Mode 2 are consistent with the changing periods of the surface spatial field and time coefficient of the first and second modes of complex empirical orthogonal function(EOF)analysis of flow anomalies in the actual equatorial ocean. This indicates that the solution does exist in the real ocean, and that El Ni?o-Southern Oscillation(ENSO) and Indian Ocean dipole(IOD) are both related to Mode 2.After considering the Indonesian throughflow, we can obtain the length of bounded equatorial ocean by taking the sum of that of the tropical Indian Ocean and the tropical Pacific Ocean, thus this wave packet can also explain the decadal variability(about 20 a) of the equatorial Pacific and Indian Oceans.展开更多
The heat budget is analyzed in the surface-layer (0-50 m) Pacific of the equatorial band (10°S-10°N), using the simulation of an ocean general circulation model from 1945 to 1993. The analysis indicates that...The heat budget is analyzed in the surface-layer (0-50 m) Pacific of the equatorial band (10°S-10°N), using the simulation of an ocean general circulation model from 1945 to 1993. The analysis indicates that downward net surface heat flux from the atmosphere and ocean advective heat fluxes play distinct roles in seasonal and interannual variabilities of surface-layer ocean temperature. The surface heat flux dominantly determines the ocean temperature in the seasonal time-scale. But, it has a negative feedback to the ocean temperature in the interannual time-scale. The interannual variability of ocean temperature is largely associated with the cold advection from off-equatorial divergent flow in the central Pacific and from upwelling in the cold tongue. Both the surface heat flux and ocean advective heat fluxes are important to the ocean temperature during an El Nino event. The ocean. advective heat fluxes are further associated with local westward trade wind in the central Pacific. These results are largely consistent with some regional observational analyses.展开更多
A regional reanalysis product-China Ocean Reanalysis（CORA）-has been developed for the China＇s seas and the adjacent areas. In this study, the intraseasonal variabilities（ISVs） in CORA are assessed by comparing wi...A regional reanalysis product-China Ocean Reanalysis（CORA）-has been developed for the China＇s seas and the adjacent areas. In this study, the intraseasonal variabilities（ISVs） in CORA are assessed by comparing with observations and two other reanalysis products（ECCO2 and SODA）. CORA shows a better performance in capturing the intraseasonal sea surface temperatures（SSTs） and the intraseasonal sea surface heights（SSHs） than ECCO2 and SODA do, probably due to its high resolution, stronger response to the intraseasonal forcing in the atmosphere（especially the Madden-Julian Oscillation）, and more available regional data for assimilation. But at the subsurface, the ISVs in CORA are likely to be weaker than reality, which is probably attributed to rare observational data for assimilation and weak diapycnal eddy diffusivity in the CORA model. According to the comparison results, CORA is a good choice for the study related to variabilities at the surface, but cares have to be taken for the study focusing on the subsurface processes.展开更多
Using surface soil moisture(SM) from ERA-Interim reanalysis and Climate Forecast System Reanalysis(CFSR) data together with simulated results from CESM, the authors evaluated the subseasonal variability of SM and expl...Using surface soil moisture(SM) from ERA-Interim reanalysis and Climate Forecast System Reanalysis(CFSR) data together with simulated results from CESM, the authors evaluated the subseasonal variability of SM and explored its basic features. Evident subseasonal variability of SM was detected in all seasons and with different datasets. However, the subseasonal variability of SM showed significant regional differences and varied with seasons. It was found that SM has large subseasonal variances in eastern China, North America, South Africa, and Australia in the summer hemisphere. The variances of the low-frequency SM variations given by ERA-Interim and CFSR are different. Overall, CFSR shows stronger variability than ERA-Interim. Through spectral analysis, it was noticed that low-frequency variations of surface SM mainly happen with periods of 10–30 days and 30–50 days. Subseasonal variations with a period of 10–30 days are dominant in eastern China and South Africa. However, subseasonal variations with periods of both 10–30 days and 30–50 days were detected in North America and Australia. Generally, CESM captures the main features of SM subseasonal variation. However, the model overestimates the subseasonal variability in all seasons in most regions, especially in the high latitudes of the Northern Hemisphere.展开更多
Based on four sets of numerical simulations prescribed with atmospheric radiative forcing and sea surface temperature(SST) forcing in the Community Atmospheric Model version 3(CAM3), the interannual and interdecadal v...Based on four sets of numerical simulations prescribed with atmospheric radiative forcing and sea surface temperature(SST) forcing in the Community Atmospheric Model version 3(CAM3), the interannual and interdecadal variabilities of the Antarctic oscillation(AAO) during austral summer were studied. It was found that the interannual variability is mainly driven by SST forcing. On the other hand, atmospheric radiative forcing plays a major role in the interdecadal variability. A cooling trend was found in the high latitudes of the Southern Hemisphere(SH) when atmospheric radiative forcing was specified in the model. This cooling trend tended to enhance the temperature gradient between the mid and high latitudes in the SH, inducing a transition of the AAO from a negative to a positive phase on the interdecadal timescale. The cooling trend was also partly weakened by the SST forcing, leading to a better simulation compared with the purely atmospheric radiative forcing run. Therefore, SST forcing cannot be ignored, although it is not as important as atmospheric radiative forcing.展开更多
Understanding variability in seed germination among populations is essential for planning an effective germplasm collection for restoration and conservation purposes.The knowledge of germination and dormancy patterns ...Understanding variability in seed germination among populations is essential for planning an effective germplasm collection for restoration and conservation purposes.The knowledge of germination and dormancy patterns among populations of desert grasses is crucial for determining the potential of the species and populations to be used for restoration and conservation as well as forage production.Variability in seed germination of Panicum turgidum Forssk and Pennisetum divisum(Gmel.)Henr.in the desert of Kuwait was evaluated in different populations in May 2017.Experiment of seed germination(25 seeds and 4 replicates)was conducted for each population at night/day temperatures of 15℃/20℃and 20℃/30℃under the following light condition:continuous darkness or 12 h/12 h light/dark.Results showed that seed masses of both species strongly varied according to their seed provenances,and both species produced heavier seeds in population with a higher soil electrical conductivity.Seed germination percentage considerably varied between two species,and the variation in P.turgidum was greater(17%–49%)than that of P.divisum(72%–93%).Germination percentage in P.turgidum was greater at high temperature(20℃/30℃)than at low temperature(15℃/20℃).However,temperature regimes had no effect on germination percentage of P.divisum seeds.Mean germination time of both species exhibited significant inter-population variability.This result is especially relevant to assure the selection of the best population of each species and the regeneration success of the species.Besides this,inter-population variability also provides valuable information for enhancing our understanding of the mechanisms that regulate seed germination and how they might be related to seed provenance.展开更多
In this study, changes in climatological conditions around the KoreanPeninsula are estimated quantitatively using various types of high order statistical analyses. Thetemperature data collected from Incheon station ha...In this study, changes in climatological conditions around the KoreanPeninsula are estimated quantitatively using various types of high order statistical analyses. Thetemperature data collected from Incheon station have been analyzed for the assessment of the climatevariation. According to our analysis, the climate changes observed over the Korean Peninsula forthe last century are similar to the global observational data in many respects. First of all, thewarming trend [+1.5℃ (100 yr)^(-1)] and the overall evolving pattern throughout the century axequite similar to each other. The temperature change in the Korean Peninsula is about two to threetimes larger than that of the global scale which may partially be ascribed to the influence ofurbanization at mid and high latitudes. In this work, a new Winter Monsoon Index (WMI) is suggestedbased on the European continental scale circulation index (EU1) pattern. Our WMI is defined as thenormalized sea level pressure (SLP) difference in the winter period between the centers of the EastSea and west of Lake Baikal in Siberia, the two eastern centers of the EU1 action patterns. A strongsimilarity is found between the time series of the WMI and surface air temperature at Incheon. TheWMI has decreased gradually since the 1920s but has shifted to a rapid increasing trend in the lasttwo decades; it was in fact accompanied by a weakening of the Siberian High and a decreasing of thenortherly during winter. Our findings of the close correlations between the surface air temperatureat Incheon and the WMI strongly indicate that our newly suggested index is unique and can be used asan efficient tool to predict climate variability in Korea.展开更多
Strip plots have been increasingly used in agricultural field experiments to better reflect the true situation of crop production on farmers’ fields, but failure to account for spatially and temporally related errors...Strip plots have been increasingly used in agricultural field experiments to better reflect the true situation of crop production on farmers’ fields, but failure to account for spatially and temporally related errors when present in the data analysis of strip plot field experiments may cause inefficient assessment of treatment effect significance. The objective of this study was to investigate patterns and degrees of the spatial and temporal variabilities in soil inorganic N level, leaf N concentration, and Normalized Difference Vegetation Index (NDVI) of cotton under no-tillage and the influences of N treatments on these variabilities. A strip plot experiment was conducted on a private farm near Brazil, Gibson County, Tennessee from 2009 through 2011. Five N treatments of 0, 45, 90, 134, and 179 kg N ha<sup>-1</sup> were implemented as side dress N in strip plots under a randomized complete block design with three replicates after 45 kg N ha<sup>-1</sup> was applied in the form of chicken litter before cotton planting. Spatial variability was present in soil inorganic N before cotton planting and after harvest, and in leaf N and canopy NDVI at the early square and early, mid-, and late bloom stages although the patterns and degrees of the spatial variabilities sometimes varied with growth stages and years. Application of the in-season side-dress N treatments often reduced the spatial variations of leaf N and NDVI, but increased those of post-harvest soil inorganic N. Out results suggest that the spatial and temporal variabilities of soil inorganic N, leaf N, and NDVI are high, and should be taken into account if possible in the data analyses of N treatment effects on related soil properties and plant characteristics of cotton in strip plot field experiment research.展开更多
The Nyong River is situated in south Cameroon. The study of the impact of climate change on the water resource of the River shows that its precipitations and flow rate are decreasing. This negative effect is reinforci...The Nyong River is situated in south Cameroon. The study of the impact of climate change on the water resource of the River shows that its precipitations and flow rate are decreasing. This negative effect is reinforcing by the fact that the water of the River is collected to feed the population of Yaoundé, the political capital of Cameroon and its environs. Given that no action can stop the variability of climate factors, it is necessary to ameliorate the management of water resource of Nyong River.展开更多
Objective This study aimed to examine the association of visit-to-visit variabilities in metabolic factors with chronic kidney disease(CKD)in Shanghai community residents.Methods We used data from a cohort study of co...Objective This study aimed to examine the association of visit-to-visit variabilities in metabolic factors with chronic kidney disease(CKD)in Shanghai community residents.Methods We used data from a cohort study of community residents who participated in three examinations in 2008,2009,and 2013,respectively.Fasting plasma glucose(FPG)level,blood pressure(BP),and lipid levels were determined in 2,109 participants at all three visits,and CKD was evaluated between the second and the third visits.Visit-to-visit variabilities in metabolic factors were described by coefficients of variation(CV)at three visits.A variability score was calculated by adding the numbers of metabolic factors with a high variability defined as the highest quartile of CV.CKD was defined as the estimated glomerular filtration rate<60 mL/min per 1.73 m2 or urinary albumin-to-creatinine ratio≥30 mg/g.Results A total of 200(9.5%)participants had CKD at the third visit.Compared with the lowest quartile of CV,the highest quartile was associated with a 70%increased risk of CKD for FPG[odds ratio,OR=1.70;95%confidence interval(CI)1.06–2.72],62%for systolic BP(OR=1.62,95%CI 1.04–2.50),and 85%for low-density lipoprotein cholesterol(OR=1.85,95%CI 1.23–2.80).Furthermore,the risk of CKD increased significantly with an increasing variability score.Compared with participants with score 0,participants with scores of 1,2,and 3 were associated with 58%(OR=1.58,95%CI 1.08–2.32),121%(OR=2.21,95%CI 1.40–3.49),and 548%(OR=6.48,95%CI 3.18–13.21)higher risks of CKD,respectively.Conclusion The visit-to-visit variabilities in metabolic factors were significantly associated with the risks of CKD in Shanghai community residents.展开更多
Acinetobacter(A.)baumannii is a Gram-negative,non-fermenting opportunistic pathogen increasingly implicated in nosocomial infections,particularly in intensive care units(ICUs).Its ability to acquire multidrug resistan...Acinetobacter(A.)baumannii is a Gram-negative,non-fermenting opportunistic pathogen increasingly implicated in nosocomial infections,particularly in intensive care units(ICUs).Its ability to acquire multidrug resistance(MDR),including to carbapenems,poses a major public health threat.Infections caused by A.baumannii-ranging from pneumonia to bloodstream and wound infections-are difficult to treat and associated with high mortality,especially in critically ill patients[1].展开更多
Using the satellite altimeter data from 1993 to 2021,this study investigates the seasonal and interannual variations of Kuroshio surface water intrusion into the East China Sea(ECS)with an emphasis on transports acros...Using the satellite altimeter data from 1993 to 2021,this study investigates the seasonal and interannual variations of Kuroshio surface water intrusion into the East China Sea(ECS)with an emphasis on transports across different isobaths.The results reveal that the intrusion variability differs among the isobaths used to identify the intrusion.On the seasonal scale,the transport volume and proportion of intrusion into the outer shelf(across 200 m isobath)are greatest in spring compared to other seasons possibly because of the relief of northerly monsoon and the increase of Kuroshio transport.However,in the inner shelf regions(across 100 m isobath),the strongest intrusion occurs in summer,with a much longer residence period and broader spatial range,though the Kuroshio moves farthest away from the coast.This implies that the Kuroshio may have the highest exchange efficiency with the ECS shelf water during summer.On the interannual scale,increased upstream transport from the Kuroshio and shoreward movement of the current almost equally contribute to the enhancement of surface water intrusion into the outer shelf regions.In contrast to the seasonal characteristics,the interannual intrusion into the shallower shelf regions(across the 120 m and 100 m isobaths)is primarily correlated to the position of the Kuroshio axis,i.e.,the closer to the coast the Kuroshio is,the more water can enter the inner continental shelf.This result highlights that the importance of factors that control the intrusion variabilities may also change between seasonal and interannual time scales when different isobaths are used.展开更多
基金the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030004)the National Natural Science Foundation of China(Grant No.42175056)+3 种基金the Natural Science Foundation of Shanghai(Grant No.21ZR1457600)Review and Summary Project of China Meteorological Administration(Grant No.FPZJ2023-044)the China Meteorological Administration Innovation and Development Project(Grant No.CXFZ2022J009)the Key Innovation Team of Climate Prediction of the China Meteorological Administration(Grant No.CMA2023ZD03).
文摘In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in the lower reaches of the YRV,focusing on the city of Shanghai.We found that about 1/3 of the 2022 HW days in Shanghai can be attributed to the long-term warming trend of global warming.During mid-summer of 2022,an enhanced western Pacific subtropical high(WPSH)and anomalous double blockings over the Ural Mountains and Sea of Okhotsk,respectively,were associated with the persistently anomalous high pressure over the YRV,leading to the extreme HW.The Pacific Decadal Oscillation played a major role in the anomalous blocking pattern associated with the HW at the decadal time scale.Also,the positive phase of the Atlantic Multidecadal Oscillation may have contributed to regulating the formation of the double-blocking pattern.Anomalous warming of both the warm pool of the western Pacific and tropical North Atlantic at the interannual time scale may also have favored the persistency of the double blocking and the anomalously strong WPSH.At the subseasonal time scale,the anomalously frequent phases 2-5 of the canonical northward propagating variability of boreal summer intraseasonal oscillation associated with the anomalous propagation of a weak Madden-Julian Oscillation suppressed the convection over the YRV and also contributed to the HW.Therefore,the 2022 extreme HW originated from multiscale forcing including both the climate warming trend and air-sea interaction at multiple time scales.
基金the National Natural Science Foundation of China(42176243)。
文摘Using European Centre for Medium-Range Weather Forecasts Reanalysis V5(ERA5)reanalysis data,this study investigated the reconstruction effects of various climate variabilities on surface wind speed in China from 1979 to 2022.The results indicated that the reconstructed annual mean wind speed and the standard deviation of the annual mean wind speed,utilizing various climate variability indices,exhibited similar spatial modes to the reanalysis data,with spatial correlation coefficients of 0.99 and 0.94,respectively.In the reconstruction of six major wind power installed capacity provinces/autonomous regions in China,the effects were notably good for Hebei and Shanxi provinces,with the correlation coefficients for the interannual regional average wind speed time series being 0.65 and 0.64,respectively.The reconstruction effects of surface wind speed differed across seasons,with spring and summer reconstructions showing the highest correlation with reanalysis data.The correlation coefficients for all seasons across most regions in China ranged between 0.4 and 0.8.Among the reconstructed seasonal wind speeds for the six provinces/autonomous regions,Shanxi Province in spring exhibited the highest correlation with the reanalysis,with a coefficient of 0.61.The large-scale climate variability indices showed good reconstruction effects on the annual mean wind speed in China,and could explain the interannual variability trends of surface wind speed in most regions of China,particularly in the main wind energy provinces/autonomous regions.
基金This work was jointly supported by China National Key R&D Program 2018YFA0605604,NSFC grants(Grant No.42088101,41875069),NSF AGS-2006553NOAA NA18OAR4310298.This is SOEST contribution number 11413,IPRC contribution number 1541,and ESMC number 357.
文摘Summer precipitation over the Yangtze River basin(YRB)in 2020 experienced a strong subseasonal and synoptic fluctuation in addition to contributing to an exceptionally large seasonal mean precipitation.The cause of this higher-frequency fluctuation is examined based on observational analyses.Apart from the continuous northward movement of the climatological mei-yu rainband,the mei-yu rainbelt in the summer of 2020 experienced multiple northward and southward swings.The cause of the swings was attributed to the subseasonal variability of southerly winds to the south and northeasterly winds to the north of the YRB.In addition,synoptic-scale variability,characterized by the eastward propagation of low-level cyclonic vorticity and precipitation anomalies,was also commonplace in the summer of 2020.While the strengthening of both the subseasonal and synoptic variabilities in the summer of 2020 was attributed to the increase of the background mean moisture,the synoptic variability was greatly affected by the subseasonal rainfall variability.As a result,both the synoptic-scale and subseasonal variabilities contributed to the north-south swings of the rainbelt.The large-scale modulations by both the seasonal mean and subseasonal anomalies provide insight regarding the optimization of issuing accurate,extended-range forecasts of extreme weather events.
基金supported by the National Basic Research Program of China(973Program,Grant No.2007CB411807)the National Marine Public Welfare Research Project of China(Grants No.201005019,201105010-12,and201105009)the National Natural Science Foundation of China(Grants No.40976006and41276018-74)
文摘Combining sea level anomalies with the mean dynamic topography derived from the geoid of the EGM08 global gravity field model and the CLS01 mean sea surface height, this study examined the characteristics of global geostrophic surface currents and the seasonal and interannual variabilities of the mean velocity of the Kuroshio （the Kuroshio source and Kuroshio extension）. The patterns of global geostrophic surface currents we derived and the actual ocean circulation are basically the same. The mean velocity of the Kuroshio source is high in winter and low in fall, and its seasonal variability accounts for 18% of its total change. The mean velocity of the Kuroshio extension is high in summer and low in winter, and its seasonal variability accounts for 25% of its total change. The interannual variabilities of the mean velocity of the Kuroshio source and Kuroshio extension are significant. The mean velocity of the Kuroshio source and ENSO index are inversely correlated. However, the relationship between the mean velocity of the Kuroshio extension and the ENSO index is not clear. Overall, the velocity of the Kuroshio increases when La Nina occurs and decreases when E1 Nino occurs.
文摘Climatic anomalies have drawn more and more attentions not only in the worldwide scientific circle, but also in the respect of many governments in the last decade. The floods and drought occurred in China and many other countries cause severe damages and lead to the crises of grain production, water resources and energy. The sustained aridity in Africa and other Continents and the land desertization make millions of people face imperilling of starvation. All these greatly affect the long-term development of nations, societies and economics
文摘ASCA observations of the two Type II AGNs, NGC 7314 and NGC 7582, show clear variations in the broad X-ray band (0.4-10keV) on short timescales -104s. Spectral analysis indicates that they both have an absorbed hard X-ray component and an unabsorbed soft "excess" component. To clarify the origin of the latter, we made a cross-correlation analysis of the two components. The results show that, for NGC 7314, the soft X-ray variability is proportional to that of the hard X-ray component. This indicates that the active nucleus of NGC 7314 must be partially covered and so the soft emission is a "leaking" of the variable hard component. For NGC 7582, there is no detectable variability in the soft component, although there is a definite one in the hard component. This indicates that the variable nucleus of NGC 7582 must be fully blocked by absorbing matter, and the soft emission is most likely the scattered component predicted by the AGN unified model.
基金This paper was supported bythe"National Key Programme for Developing Basic Sci-ences"Project G1998040900(I) and Project ZKCXZ-SW-210 of the Chinese Academy of Sciences.
文摘The variabilities of the East Asian summer monsoon arc an important research issue in China, Japan, and Korea. in this paper, progresses of recent studies on the intrascasonal, interannual, and interdecadal variations of the East Asian monsoon, especially the East Asian summer monsoon, and their causes are reviewed. Particularly, studies on the effects of the ENSO cycle, the western Pacific warm pool, the Tibetan Plateau and land surface processes on the variations of the East Asian summer monsoon are systematically reviewed.
基金National Natural Science Foundation of China(41375065)National Natural Science Foundation of China(41461164005,41230527)National Key Research and Development Program of China(2016YFA0600603)
文摘In this paper, we mainly summarize and review the progresses in recent climatological studies(by CMSR,IAP/CAS and some associated domestic and international institutions) on the interannual and interdecadal variabilities of monsoon troughs and their impacts on tropical cyclones and typhoons(TCs) geneses over the western North Pacific Ocean. The climatological characteristics of monsoon troughs and four types of circulation patterns favorable to TCs genesis over the western North Pacific Ocean in summer and autumn are given in this paper. It is also shown in this paper that the monsoon trough over the western North Pacific Ocean has obvious interannual and interdecadal variabilities. Especially, it is revealed in this paper that the interannual and interdecadal variabilities of the monsoon trough over the western North Pacific Ocean influence the TCs genesis not only through the impact on distributions of the vorticity in the lower troposphere and the divergence in the upper troposphere, the water vapor in the mid-and lower troposphere and the vertical shear of wind fields between the upper and lower troposphere over the western North Pacific Ocean, but also through the dynamical effects of the transition between convectively coupled tropical waves and providing disturbance energy. Besides, some climatological problems associated with TCs activity over the western North Pacific Ocean that need to be studied further are also pointed out in this paper.
基金The National Major Research High Performance Computing Program of China under contract 2016YFB0200800the Strategic Priority Research Program of Chinese Academy of Sciences under contract No.XDA20060501
文摘Linearized shallow water perturbation equations with approximation in an equatorial β plane are used to obtain the analytical solution of wave packet anomalies in the upper bounded equatorial ocean. The main results are as follows. The wave packet is a superposition of eastward travelling Kelvin waves and westward travelling Rossby waves with the slowest speed, and satisfies the boundary conditions of eastern and western coasts, respectively.The decay coefficient of this solution to the north and south sides of the equator is inversely proportional only to the phase velocity of Kelvin waves in the upper water. The oscillation frequency of the wave packet, which is also the natural frequency of the ocean, is proportional to its mode number and the phase velocity of Kelvin waves and is inversely proportional to the length of the equatorial ocean in the east-west direction. The flow anomalies of the wave packet of Mode 1 most of the time appear as zonal flows with the same direction. They reach the maximum at the center of the equatorial ocean and decay rapidly away from the equator, manifested as equatorially trapped waves. The flow anomalies of the wave packet of Mode 2 appear as the zonal flows with the same direction most of the time in half of the ocean, and are always 0 at the center of the entire ocean which indicates stagnation, while decaying away from the equator with the same speed as that of Mode 1. The spatial structure and oscillation period of the wave packet solution of Mode 1 and Mode 2 are consistent with the changing periods of the surface spatial field and time coefficient of the first and second modes of complex empirical orthogonal function(EOF)analysis of flow anomalies in the actual equatorial ocean. This indicates that the solution does exist in the real ocean, and that El Ni?o-Southern Oscillation(ENSO) and Indian Ocean dipole(IOD) are both related to Mode 2.After considering the Indonesian throughflow, we can obtain the length of bounded equatorial ocean by taking the sum of that of the tropical Indian Ocean and the tropical Pacific Ocean, thus this wave packet can also explain the decadal variability(about 20 a) of the equatorial Pacific and Indian Oceans.
文摘The heat budget is analyzed in the surface-layer (0-50 m) Pacific of the equatorial band (10°S-10°N), using the simulation of an ocean general circulation model from 1945 to 1993. The analysis indicates that downward net surface heat flux from the atmosphere and ocean advective heat fluxes play distinct roles in seasonal and interannual variabilities of surface-layer ocean temperature. The surface heat flux dominantly determines the ocean temperature in the seasonal time-scale. But, it has a negative feedback to the ocean temperature in the interannual time-scale. The interannual variability of ocean temperature is largely associated with the cold advection from off-equatorial divergent flow in the central Pacific and from upwelling in the cold tongue. Both the surface heat flux and ocean advective heat fluxes are important to the ocean temperature during an El Nino event. The ocean. advective heat fluxes are further associated with local westward trade wind in the central Pacific. These results are largely consistent with some regional observational analyses.
基金The National Natural Science Foundation of China under contract Nos 41206178,41376034,41276018 and 41321004the Fundamental Research Funds for the Central Universities under contract No.2014B30514+1 种基金the open project supplied by the Key Laboratory of Marine Environmental Information Technology,National Marine Data and Information Service,State Oceanic Administration:Effectiveness on the intraseasonal scale in CORA(2015–2016)the Predictability of Ocean Dynamical System Project under Contract No.151053
文摘A regional reanalysis product-China Ocean Reanalysis（CORA）-has been developed for the China＇s seas and the adjacent areas. In this study, the intraseasonal variabilities（ISVs） in CORA are assessed by comparing with observations and two other reanalysis products（ECCO2 and SODA）. CORA shows a better performance in capturing the intraseasonal sea surface temperatures（SSTs） and the intraseasonal sea surface heights（SSHs） than ECCO2 and SODA do, probably due to its high resolution, stronger response to the intraseasonal forcing in the atmosphere（especially the Madden-Julian Oscillation）, and more available regional data for assimilation. But at the subsurface, the ISVs in CORA are likely to be weaker than reality, which is probably attributed to rare observational data for assimilation and weak diapycnal eddy diffusivity in the CORA model. According to the comparison results, CORA is a good choice for the study related to variabilities at the surface, but cares have to be taken for the study focusing on the subsurface processes.
基金This study was supported by the National Natural Science Foundation of China[grant number 41625019].
文摘Using surface soil moisture(SM) from ERA-Interim reanalysis and Climate Forecast System Reanalysis(CFSR) data together with simulated results from CESM, the authors evaluated the subseasonal variability of SM and explored its basic features. Evident subseasonal variability of SM was detected in all seasons and with different datasets. However, the subseasonal variability of SM showed significant regional differences and varied with seasons. It was found that SM has large subseasonal variances in eastern China, North America, South Africa, and Australia in the summer hemisphere. The variances of the low-frequency SM variations given by ERA-Interim and CFSR are different. Overall, CFSR shows stronger variability than ERA-Interim. Through spectral analysis, it was noticed that low-frequency variations of surface SM mainly happen with periods of 10–30 days and 30–50 days. Subseasonal variations with a period of 10–30 days are dominant in eastern China and South Africa. However, subseasonal variations with periods of both 10–30 days and 30–50 days were detected in North America and Australia. Generally, CESM captures the main features of SM subseasonal variation. However, the model overestimates the subseasonal variability in all seasons in most regions, especially in the high latitudes of the Northern Hemisphere.
基金supported by the Carbon Budget and Related Issues of the Chinese Academy of Sciences (Grant No. XDA05110201)the National Basic Research Program of China (Grant No. 2010CB951901)
文摘Based on four sets of numerical simulations prescribed with atmospheric radiative forcing and sea surface temperature(SST) forcing in the Community Atmospheric Model version 3(CAM3), the interannual and interdecadal variabilities of the Antarctic oscillation(AAO) during austral summer were studied. It was found that the interannual variability is mainly driven by SST forcing. On the other hand, atmospheric radiative forcing plays a major role in the interdecadal variability. A cooling trend was found in the high latitudes of the Southern Hemisphere(SH) when atmospheric radiative forcing was specified in the model. This cooling trend tended to enhance the temperature gradient between the mid and high latitudes in the SH, inducing a transition of the AAO from a negative to a positive phase on the interdecadal timescale. The cooling trend was also partly weakened by the SST forcing, leading to a better simulation compared with the purely atmospheric radiative forcing run. Therefore, SST forcing cannot be ignored, although it is not as important as atmospheric radiative forcing.
基金supported by the Kuwait Institute for Scientific Research(KISR)
文摘Understanding variability in seed germination among populations is essential for planning an effective germplasm collection for restoration and conservation purposes.The knowledge of germination and dormancy patterns among populations of desert grasses is crucial for determining the potential of the species and populations to be used for restoration and conservation as well as forage production.Variability in seed germination of Panicum turgidum Forssk and Pennisetum divisum(Gmel.)Henr.in the desert of Kuwait was evaluated in different populations in May 2017.Experiment of seed germination(25 seeds and 4 replicates)was conducted for each population at night/day temperatures of 15℃/20℃and 20℃/30℃under the following light condition:continuous darkness or 12 h/12 h light/dark.Results showed that seed masses of both species strongly varied according to their seed provenances,and both species produced heavier seeds in population with a higher soil electrical conductivity.Seed germination percentage considerably varied between two species,and the variation in P.turgidum was greater(17%–49%)than that of P.divisum(72%–93%).Germination percentage in P.turgidum was greater at high temperature(20℃/30℃)than at low temperature(15℃/20℃).However,temperature regimes had no effect on germination percentage of P.divisum seeds.Mean germination time of both species exhibited significant inter-population variability.This result is especially relevant to assure the selection of the best population of each species and the regeneration success of the species.Besides this,inter-population variability also provides valuable information for enhancing our understanding of the mechanisms that regulate seed germination and how they might be related to seed provenance.
文摘In this study, changes in climatological conditions around the KoreanPeninsula are estimated quantitatively using various types of high order statistical analyses. Thetemperature data collected from Incheon station have been analyzed for the assessment of the climatevariation. According to our analysis, the climate changes observed over the Korean Peninsula forthe last century are similar to the global observational data in many respects. First of all, thewarming trend [+1.5℃ (100 yr)^(-1)] and the overall evolving pattern throughout the century axequite similar to each other. The temperature change in the Korean Peninsula is about two to threetimes larger than that of the global scale which may partially be ascribed to the influence ofurbanization at mid and high latitudes. In this work, a new Winter Monsoon Index (WMI) is suggestedbased on the European continental scale circulation index (EU1) pattern. Our WMI is defined as thenormalized sea level pressure (SLP) difference in the winter period between the centers of the EastSea and west of Lake Baikal in Siberia, the two eastern centers of the EU1 action patterns. A strongsimilarity is found between the time series of the WMI and surface air temperature at Incheon. TheWMI has decreased gradually since the 1920s but has shifted to a rapid increasing trend in the lasttwo decades; it was in fact accompanied by a weakening of the Siberian High and a decreasing of thenortherly during winter. Our findings of the close correlations between the surface air temperatureat Incheon and the WMI strongly indicate that our newly suggested index is unique and can be used asan efficient tool to predict climate variability in Korea.
文摘Strip plots have been increasingly used in agricultural field experiments to better reflect the true situation of crop production on farmers’ fields, but failure to account for spatially and temporally related errors when present in the data analysis of strip plot field experiments may cause inefficient assessment of treatment effect significance. The objective of this study was to investigate patterns and degrees of the spatial and temporal variabilities in soil inorganic N level, leaf N concentration, and Normalized Difference Vegetation Index (NDVI) of cotton under no-tillage and the influences of N treatments on these variabilities. A strip plot experiment was conducted on a private farm near Brazil, Gibson County, Tennessee from 2009 through 2011. Five N treatments of 0, 45, 90, 134, and 179 kg N ha<sup>-1</sup> were implemented as side dress N in strip plots under a randomized complete block design with three replicates after 45 kg N ha<sup>-1</sup> was applied in the form of chicken litter before cotton planting. Spatial variability was present in soil inorganic N before cotton planting and after harvest, and in leaf N and canopy NDVI at the early square and early, mid-, and late bloom stages although the patterns and degrees of the spatial variabilities sometimes varied with growth stages and years. Application of the in-season side-dress N treatments often reduced the spatial variations of leaf N and NDVI, but increased those of post-harvest soil inorganic N. Out results suggest that the spatial and temporal variabilities of soil inorganic N, leaf N, and NDVI are high, and should be taken into account if possible in the data analyses of N treatment effects on related soil properties and plant characteristics of cotton in strip plot field experiment research.
文摘The Nyong River is situated in south Cameroon. The study of the impact of climate change on the water resource of the River shows that its precipitations and flow rate are decreasing. This negative effect is reinforcing by the fact that the water of the River is collected to feed the population of Yaoundé, the political capital of Cameroon and its environs. Given that no action can stop the variability of climate factors, it is necessary to ameliorate the management of water resource of Nyong River.
基金the grants from the National Key R&D Program of China[2017YFC1310700,2016YFC1305600,2018YFC1311800,2016YFC0901200]the National Natural Science Foundation of China[81870560,81700764,81561128019]+4 种基金the Shanghai Municipal Government[18411951800]the Shanghai Shenkang Hospital Development Center[SHDC12019101]the Shanghai Jiaotong University School of Medicine[DLY201801]the Ruijin Hospital[2018CR002]the Shanghai Municipal Education Commission[HJWR20196619]。
文摘Objective This study aimed to examine the association of visit-to-visit variabilities in metabolic factors with chronic kidney disease(CKD)in Shanghai community residents.Methods We used data from a cohort study of community residents who participated in three examinations in 2008,2009,and 2013,respectively.Fasting plasma glucose(FPG)level,blood pressure(BP),and lipid levels were determined in 2,109 participants at all three visits,and CKD was evaluated between the second and the third visits.Visit-to-visit variabilities in metabolic factors were described by coefficients of variation(CV)at three visits.A variability score was calculated by adding the numbers of metabolic factors with a high variability defined as the highest quartile of CV.CKD was defined as the estimated glomerular filtration rate<60 mL/min per 1.73 m2 or urinary albumin-to-creatinine ratio≥30 mg/g.Results A total of 200(9.5%)participants had CKD at the third visit.Compared with the lowest quartile of CV,the highest quartile was associated with a 70%increased risk of CKD for FPG[odds ratio,OR=1.70;95%confidence interval(CI)1.06–2.72],62%for systolic BP(OR=1.62,95%CI 1.04–2.50),and 85%for low-density lipoprotein cholesterol(OR=1.85,95%CI 1.23–2.80).Furthermore,the risk of CKD increased significantly with an increasing variability score.Compared with participants with score 0,participants with scores of 1,2,and 3 were associated with 58%(OR=1.58,95%CI 1.08–2.32),121%(OR=2.21,95%CI 1.40–3.49),and 548%(OR=6.48,95%CI 3.18–13.21)higher risks of CKD,respectively.Conclusion The visit-to-visit variabilities in metabolic factors were significantly associated with the risks of CKD in Shanghai community residents.
基金supported by ICMR-RMRC intramural fund(RMRC/IM/2022/26).
文摘Acinetobacter(A.)baumannii is a Gram-negative,non-fermenting opportunistic pathogen increasingly implicated in nosocomial infections,particularly in intensive care units(ICUs).Its ability to acquire multidrug resistance(MDR),including to carbapenems,poses a major public health threat.Infections caused by A.baumannii-ranging from pneumonia to bloodstream and wound infections-are difficult to treat and associated with high mortality,especially in critically ill patients[1].
基金The National Natural Science Foundation of China under contract No.42276003the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University under contract No.SL2021MS021.
文摘Using the satellite altimeter data from 1993 to 2021,this study investigates the seasonal and interannual variations of Kuroshio surface water intrusion into the East China Sea(ECS)with an emphasis on transports across different isobaths.The results reveal that the intrusion variability differs among the isobaths used to identify the intrusion.On the seasonal scale,the transport volume and proportion of intrusion into the outer shelf(across 200 m isobath)are greatest in spring compared to other seasons possibly because of the relief of northerly monsoon and the increase of Kuroshio transport.However,in the inner shelf regions(across 100 m isobath),the strongest intrusion occurs in summer,with a much longer residence period and broader spatial range,though the Kuroshio moves farthest away from the coast.This implies that the Kuroshio may have the highest exchange efficiency with the ECS shelf water during summer.On the interannual scale,increased upstream transport from the Kuroshio and shoreward movement of the current almost equally contribute to the enhancement of surface water intrusion into the outer shelf regions.In contrast to the seasonal characteristics,the interannual intrusion into the shallower shelf regions(across the 120 m and 100 m isobaths)is primarily correlated to the position of the Kuroshio axis,i.e.,the closer to the coast the Kuroshio is,the more water can enter the inner continental shelf.This result highlights that the importance of factors that control the intrusion variabilities may also change between seasonal and interannual time scales when different isobaths are used.
