Precipitation on the Tibetan Plateau(TP)has an important effect on the water supply and demand of the downstream population.Involving recent climate change,the multi-decadal variations of the impact of El Niño-So...Precipitation on the Tibetan Plateau(TP)has an important effect on the water supply and demand of the downstream population.Involving recent climate change,the multi-decadal variations of the impact of El Niño-Southern Oscillation(ENSO)events on regional climate were observed.In this work,the authors investigated the changes in summer precipitation over TP during 1950-2019.At the multi-decadal scale,the authors found that the inhabiting impact of El Niño events on the TP summer precipitation has strengthened since the late 1970s.The main factor contributing to this phenomenon is the significant amplification in the decadal amplitude of El Niño during 1978-2019 accompanied by a discernible escalation in the frequency of El Niño events.This phenomenon induces anomalous perturbations in sea surface temperatures(SST)within the tropical Indo-Pacific region,consequently weakening the atmospheric vapor transport from the western Pacific to the TP.Additionally,conspicuous anomalies in subsidence motion are observed longitudinally and latitudinally across the TP which significantly contributes to a curtailed supply of atmospheric moisture.These results bear profound implications for the multi-decadal prediction of the TP climate.展开更多
The aim of the present study was to identify multi-decadal variability （MDV） relative to the current centennial global warming trend in available observation data.The centennial global wanning trend was first identi...The aim of the present study was to identify multi-decadal variability （MDV） relative to the current centennial global warming trend in available observation data.The centennial global wanning trend was first identified in the global mean surface temperature （STgm） data.The MDV was identified based on three sets of climate variables,including sea surface temperature （SST）,ocean temperature from the surface to 700 m,and the NCEP and ERA40 reanalysis datasets,respectively.All variables were detrended and low-pass filtered.Through three independent EOF analyses of the filtered variables,all results consistently showed two dominant modes,with their respective temporal variability resembling the Pacific Decadal Oscillation/Inter-decadal Pacific Oscillation （PDO/IPO） and the Atlantic Multi-decadal Oscillation （AMO）.The spatial structure of the PDO-like oscillation is characterized by an ENSO-like structure and hemispheric symmetric features.The structure associated with the AMO-like oscillation exhibits hemispheric asymmetric features with anomalous warm air over Eurasia and warm SST in the Atlantic and Pacific basin north of 10°S,and cold SST over the southern oceans.The Pacific and Atlantic MDV in upper-ocean temperature suggest that they are mutually linked.We also found that the PDO-like and AMO-like oscillations are almost equally important in global-scale MDV by EOF analyses.In the period 1975-2005,the evolution of the two oscillations has given rise to strong temperature trends and has contributed almost half of the STgm warming.Hereon,in the next decade,the two oscillations are expected to slow down the global warming trends.展开更多
We investigate global temperature data produced by the Climate Research Unit at the University of East Anglia (CRU) and the Berkeley Earth Surface Temperature consortium (BEST). We first fit the 1850-2010 data with po...We investigate global temperature data produced by the Climate Research Unit at the University of East Anglia (CRU) and the Berkeley Earth Surface Temperature consortium (BEST). We first fit the 1850-2010 data with polynomials of degrees 1 to 9. A significant ~60-yr oscillation is accounted for as soon as degree 4 is reached. This oscillation is even better modeled as a broken line, more precisely a series of ~30-yr long linear segments, with slope breaks (singularities) in ~1904, ~1940, and ~1974 (±3 yr), and a possible recent occurrence at the turn of the 20th century. Oceanic indices PDO (Pacific Decadal Oscillation) and AMO (Atlantic Multidecadal Oscillation) have undergone major changes (respectively of sign and slope) roughly at the same times as the temperature slope breaks. This can be interpreted with a system of oceanic non-linear coupled oscillators with abrupt mode shifts. Thus, the Earth’s climate may have entered a new mode (a new ~30-yr episode) near the turn of the 20th century: no further temperature increase, a dominantly negative PDO index and a decreasing AMO index might be expected for the next decade or two.展开更多
Most model generated projections of climate change for the future decades only consider anthro- pogenic activities. It is hard to think about the effects of solar activity and volcano effects, because the pre- diction...Most model generated projections of climate change for the future decades only consider anthro- pogenic activities. It is hard to think about the effects of solar activity and volcano effects, because the pre- dictions of both solar activity and volcano effects are difficult. But as we know, the sun is the source of en- ergy for the Earth＇s climate system, and observations show it to be a variable star.展开更多
As large-scale ocean circulation is a key regulator in the redistribution of oceanic energy, evaluating the multi-decadal trends in the western Pacific Ocean circulation under global warming is essential for not only ...As large-scale ocean circulation is a key regulator in the redistribution of oceanic energy, evaluating the multi-decadal trends in the western Pacific Ocean circulation under global warming is essential for not only understanding the basic physical processes but also predicting future climate change in the western Pacific. Employing the hydrological observations of World Ocean Atlas 2018(WOA18) from 1955 to 2017, this study calculated the geostrophic currents, volume transport and multidecadal trends for the North Equatorial Current(NEC), the North Equatorial Countercurrent(NECC), the Mindanao Current(MC), the Kuroshio Current(KC) in the origin and the New Guinea Coastal Undercurrent(NGCUC) within tropical western Pacific Ocean over multi-decades. Furthermore, this study examined the contributions of temperature and salinity variations. The results showed significant strengthening trends in NEC, MC and NGCUC over the past six decades, which is mainly contributed by temperature variations and consistent with the tendency in the dynamic height pattern. Zonal wind stress averaged over the western Pacific Ocean in the same latitude of each current represents the decadal variation and multi-decadal trends in corresponding ocean currents, indicating that the trade wind forcing plays an important role in the decadal trend in the tropical western Pacific circulation. Uncertainties in the observed hydrological data and trends in the currents over the tropical western Pacific are also discussed. Given that the WOA18 dataset covers most of the historical hydrological sampling data for the tropical western Pacific, this paper provides important observational information on the multi-decadal trend of the large-scale ocean circulation in the western Pacific.展开更多
Subject Code:D05Under support of the National Natural Science Foundation of China,a concerted study by Dr.Huang Gang(黄刚)from the Institute of Atmospheric Physics,Chinese Academy of Sciences,climate scientist Jing-Ji...Subject Code:D05Under support of the National Natural Science Foundation of China,a concerted study by Dr.Huang Gang(黄刚)from the Institute of Atmospheric Physics,Chinese Academy of Sciences,climate scientist Jing-Jia Luo from the Australian Bureau of Meteorology,Dr.Yao Shuailei(姚帅磊)from the Institute展开更多
In this study, the impacts of the Pacific Decadal Oscillation （PDO） and the Atlantic Multidecadal Oscillation （AMO） on the western Pacific warm pool （WPWP） were investigated. Our results show that the WPWP is li...In this study, the impacts of the Pacific Decadal Oscillation （PDO） and the Atlantic Multidecadal Oscillation （AMO） on the western Pacific warm pool （WPWP） were investigated. Our results show that the WPWP is linked with the PDO and the AMO at multiple time scales. On the seasonal time scales, the WPWP and the PDO/AMO reinforce each other, while at decadal time scales the forcing roles of the PDO and the AMO dominate. Notably, a positive PDO tends to enlarge the WPWP at both seasonal and decadal time scales, while a positive AMO tends to reduce the WPWP at decadal time scales. Furthermore, the decadal variability of the WPWP can be well predicted based on the PDO and AMO.展开更多
Using multichannel singular spectrum analysis （MSSA） we decomposed climatic time se- ries into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtrac...Using multichannel singular spectrum analysis （MSSA） we decomposed climatic time se- ries into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtracted. Similar quasi 60 and 20 year periodic os- cillations have been found in the global mean Earth temperature anomaly （HadCRUT4） and global mean sea level （GMSL）. Similar cycles were also found in Earth rotation variation. Over the last 160 years multi-decadal change of Earth＇s rotation velocity is correlated with the 60-year temperature anomaly, and Chandler wobble envelope reproduces the form of the 60-year oscillation noticed in GMSL. The quasi 20-year oscillation observed in GMSL is correlated with the Chandler wobble excitation. So, we assume that Earth＇s rotation and climate indexes are connected. Despite of all the clues hinting this connection, no sound conclusion can be done as far as ocean circulation modelling is not able to correctly catch angular momentum of the oscillatory modes.展开更多
The ear-shaped thermal front （ESTF）, formed by the convergence of the Yellow Sea Warm Current （YSWC） and the Shandong Coastal Current （SCC）, is a very important oceanic phenomenon in the Yellow Sea （YS） in win...The ear-shaped thermal front （ESTF）, formed by the convergence of the Yellow Sea Warm Current （YSWC） and the Shandong Coastal Current （SCC）, is a very important oceanic phenomenon in the Yellow Sea （YS） in winter. In situ measurements and reanalysis datasets all demonstrate that the ESTF has been weakening during 1950s-1990s, and a similar weakening trend is also found in winter monsoon over the YS. Numerical experiments show that the weakening of winter monsoon can induce an anomalous circulation in the YS on multi-decadal timescale with northward anomalous currents along China＇s coast and southward anomalous currents in the central YS--generally opposite to seasonal mean circulation. The anomalous circulation causes slowdown of the YSWC and the SCC, and thus weakens the ESTF. Since the ESTF plays important roles in regional ocean dynamics and air-sea interactions, its weakening has important implications for regional climate in the YS in winter.展开更多
We analyze ten of the longest (127 to 230 year-long) time series of European daily temperatures available from five different Köppen-Geiger climate classes. We split these according to the level of solar cycl...We analyze ten of the longest (127 to 230 year-long) time series of European daily temperatures available from five different Köppen-Geiger climate classes. We split these according to the level of solar cycle activity (H for “higher than median” and L for “lower than median”). This reveals coherent patterns in the temperature differences: when TH-TL?are stacked according to their calendar date, the daily averages from January 1 to December 31st disclose characteristic features in addition to the dominant annual seasonal wave, namely variations up to 2°C lasting for about 1.5 to 3 months. The five observatories at intermediate latitudes in a band from Oxford in the West to Prague in the East (same climate class) have very similar signatures. These similarities are most unlikely to be due to pure chance (confirmed by confidence levels in excess of 99% with the Kolmogorov-Smirnov and Kuiper nonparametric tests). The TH-TL patterns carry a regional signature, modulated by a more local response function. On the other hand, northern European observatories (St Petersburg and Arkhangelsk), those south of the Alps (Milan and Bologna), and the easternmost one in Astrakhan, corresponding to different climate classes, have different signatures. Similarly, preliminary study of long air pressure recordings confirms what emerges from the analysis of temperatures. These new observations lead us to conclude that the climate in different regions presents different responses to variations in solar activity. Moreover, the distributions of the lower, middle, and higher quartiles of the temperature and pressure indices in solar cycles with high versus low activity are significantly different, providing further robust statistical confirmation to this conclusion (confidence level higher to much higher than 99% using the Kuiper test).展开更多
The Fourth Assessment Report (AR4) of the Intergovernmental Panel of Climate Change (IPCC) concluded that the climate projection using climate models that took account of both human and natural factors provided credib...The Fourth Assessment Report (AR4) of the Intergovernmental Panel of Climate Change (IPCC) concluded that the climate projection using climate models that took account of both human and natural factors provided credible quantitative estimates of future climate change; however, the mismatches between the IPCC AR4 model ensembles and the observations, especially the multi-decadal variability (MDV), have cast shadows on the confidence of the model-based decadal projections of future cli mate. This paper reports an evaluation of many individual runs of AR4 models in the simulation of past global mean tempera ture. We find that most of the individual model runs fail to reproduce the MDV of past climate, which may have led to the overestimation of the projection of global warming for the next 40 years or so. Based on such an evaluation, we propose an al ternative approach, in which the MDV signal is taken into account, to project the global mean temperature for the next 40 years and obtain that the global warming during 2011–2050 could be much smaller than the AR4 projection.展开更多
基金This research was funded by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0105)the Shenzhen Science and Technology Program(JCYJ20210324131810029)+2 种基金the National Natural Science Foundation of China(72293604,42275017)the Guangdong Provincial College Innovation Team Project(060313452101)the Program for scientific research start-up funds of Guangdong Ocean University(R17056).
文摘Precipitation on the Tibetan Plateau(TP)has an important effect on the water supply and demand of the downstream population.Involving recent climate change,the multi-decadal variations of the impact of El Niño-Southern Oscillation(ENSO)events on regional climate were observed.In this work,the authors investigated the changes in summer precipitation over TP during 1950-2019.At the multi-decadal scale,the authors found that the inhabiting impact of El Niño events on the TP summer precipitation has strengthened since the late 1970s.The main factor contributing to this phenomenon is the significant amplification in the decadal amplitude of El Niño during 1978-2019 accompanied by a discernible escalation in the frequency of El Niño events.This phenomenon induces anomalous perturbations in sea surface temperatures(SST)within the tropical Indo-Pacific region,consequently weakening the atmospheric vapor transport from the western Pacific to the TP.Additionally,conspicuous anomalies in subsidence motion are observed longitudinally and latitudinally across the TP which significantly contributes to a curtailed supply of atmospheric moisture.These results bear profound implications for the multi-decadal prediction of the TP climate.
基金supported by the National Science Council (Grant No. NSC 98-2745-M-002-011-ASP)the National Basic Research Program "973" (Grant No. 2010CB950401, 2012CB955204)+1 种基金the research foundation of NUIST, the National Natural Science Foundation of China (Grant No. 41005047)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘The aim of the present study was to identify multi-decadal variability （MDV） relative to the current centennial global warming trend in available observation data.The centennial global wanning trend was first identified in the global mean surface temperature （STgm） data.The MDV was identified based on three sets of climate variables,including sea surface temperature （SST）,ocean temperature from the surface to 700 m,and the NCEP and ERA40 reanalysis datasets,respectively.All variables were detrended and low-pass filtered.Through three independent EOF analyses of the filtered variables,all results consistently showed two dominant modes,with their respective temporal variability resembling the Pacific Decadal Oscillation/Inter-decadal Pacific Oscillation （PDO/IPO） and the Atlantic Multi-decadal Oscillation （AMO）.The spatial structure of the PDO-like oscillation is characterized by an ENSO-like structure and hemispheric symmetric features.The structure associated with the AMO-like oscillation exhibits hemispheric asymmetric features with anomalous warm air over Eurasia and warm SST in the Atlantic and Pacific basin north of 10°S,and cold SST over the southern oceans.The Pacific and Atlantic MDV in upper-ocean temperature suggest that they are mutually linked.We also found that the PDO-like and AMO-like oscillations are almost equally important in global-scale MDV by EOF analyses.In the period 1975-2005,the evolution of the two oscillations has given rise to strong temperature trends and has contributed almost half of the STgm warming.Hereon,in the next decade,the two oscillations are expected to slow down the global warming trends.
基金financial support from IPGP as part of the IEPT RAS-IPGP cooperation.IPGP Contribution NS 3391.
文摘We investigate global temperature data produced by the Climate Research Unit at the University of East Anglia (CRU) and the Berkeley Earth Surface Temperature consortium (BEST). We first fit the 1850-2010 data with polynomials of degrees 1 to 9. A significant ~60-yr oscillation is accounted for as soon as degree 4 is reached. This oscillation is even better modeled as a broken line, more precisely a series of ~30-yr long linear segments, with slope breaks (singularities) in ~1904, ~1940, and ~1974 (±3 yr), and a possible recent occurrence at the turn of the 20th century. Oceanic indices PDO (Pacific Decadal Oscillation) and AMO (Atlantic Multidecadal Oscillation) have undergone major changes (respectively of sign and slope) roughly at the same times as the temperature slope breaks. This can be interpreted with a system of oceanic non-linear coupled oscillators with abrupt mode shifts. Thus, the Earth’s climate may have entered a new mode (a new ~30-yr episode) near the turn of the 20th century: no further temperature increase, a dominantly negative PDO index and a decreasing AMO index might be expected for the next decade or two.
基金supported by National Natural Science Foundation of China(No.41175066 and 41305054)
文摘Most model generated projections of climate change for the future decades only consider anthro- pogenic activities. It is hard to think about the effects of solar activity and volcano effects, because the pre- dictions of both solar activity and volcano effects are difficult. But as we know, the sun is the source of en- ergy for the Earth＇s climate system, and observations show it to be a variable star.
基金supported by the National Natural Science Foundation of China (Grant No. 41776018)the Strategic Priority Research Program of Chinese Academy of Sciences (CAS) (Grant No. XDB42010403)+3 种基金the National Natural Science Foundation of China (Grant No. 91858101)the Key Deployment Project of Centre for Ocean MegaResearch of Science of CAS (Grant Nos. COMS2019Q01 & COMS2019Q03)the CAS-CSIRO Project Fund (Grant No. 133244KYSB20190031)SH is a member of the Youth Innovation Promotion Association of CAS (Grant No. 2018240)。
文摘As large-scale ocean circulation is a key regulator in the redistribution of oceanic energy, evaluating the multi-decadal trends in the western Pacific Ocean circulation under global warming is essential for not only understanding the basic physical processes but also predicting future climate change in the western Pacific. Employing the hydrological observations of World Ocean Atlas 2018(WOA18) from 1955 to 2017, this study calculated the geostrophic currents, volume transport and multidecadal trends for the North Equatorial Current(NEC), the North Equatorial Countercurrent(NECC), the Mindanao Current(MC), the Kuroshio Current(KC) in the origin and the New Guinea Coastal Undercurrent(NGCUC) within tropical western Pacific Ocean over multi-decades. Furthermore, this study examined the contributions of temperature and salinity variations. The results showed significant strengthening trends in NEC, MC and NGCUC over the past six decades, which is mainly contributed by temperature variations and consistent with the tendency in the dynamic height pattern. Zonal wind stress averaged over the western Pacific Ocean in the same latitude of each current represents the decadal variation and multi-decadal trends in corresponding ocean currents, indicating that the trade wind forcing plays an important role in the decadal trend in the tropical western Pacific circulation. Uncertainties in the observed hydrological data and trends in the currents over the tropical western Pacific are also discussed. Given that the WOA18 dataset covers most of the historical hydrological sampling data for the tropical western Pacific, this paper provides important observational information on the multi-decadal trend of the large-scale ocean circulation in the western Pacific.
文摘Subject Code:D05Under support of the National Natural Science Foundation of China,a concerted study by Dr.Huang Gang(黄刚)from the Institute of Atmospheric Physics,Chinese Academy of Sciences,climate scientist Jing-Jia Luo from the Australian Bureau of Meteorology,Dr.Yao Shuailei(姚帅磊)from the Institute
基金the National Natural Science Foundation of China (NSFC)major project (Grant No. 40890155)NSFC Distin-guished Young Investigator Project (Grant No. 40788002)
文摘In this study, the impacts of the Pacific Decadal Oscillation （PDO） and the Atlantic Multidecadal Oscillation （AMO） on the western Pacific warm pool （WPWP） were investigated. Our results show that the WPWP is linked with the PDO and the AMO at multiple time scales. On the seasonal time scales, the WPWP and the PDO/AMO reinforce each other, while at decadal time scales the forcing roles of the PDO and the AMO dominate. Notably, a positive PDO tends to enlarge the WPWP at both seasonal and decadal time scales, while a positive AMO tends to reduce the WPWP at decadal time scales. Furthermore, the decadal variability of the WPWP can be well predicted based on the PDO and AMO.
基金supported by Russian Foundation for Basic Research (16-05-00753)partially supported by NSF/IGFA (ICER-1342644)
文摘Using multichannel singular spectrum analysis （MSSA） we decomposed climatic time se- ries into principal components, and compared them with Earth rotation parameters. The global warming trends were initially subtracted. Similar quasi 60 and 20 year periodic os- cillations have been found in the global mean Earth temperature anomaly （HadCRUT4） and global mean sea level （GMSL）. Similar cycles were also found in Earth rotation variation. Over the last 160 years multi-decadal change of Earth＇s rotation velocity is correlated with the 60-year temperature anomaly, and Chandler wobble envelope reproduces the form of the 60-year oscillation noticed in GMSL. The quasi 20-year oscillation observed in GMSL is correlated with the Chandler wobble excitation. So, we assume that Earth＇s rotation and climate indexes are connected. Despite of all the clues hinting this connection, no sound conclusion can be done as far as ocean circulation modelling is not able to correctly catch angular momentum of the oscillatory modes.
基金The National Basic Research Program(973 Program) of China under contract No.2012CB955601the National Natural Science Foundation of China under contract Nos 41576028 and 41306032+1 种基金the NSFC Shandong Joint Fund for Marine Science Research Centers under contract No.U1606405the Basic Scientific Research Fund for National Public Institutes of China under contract Nos GY2010T02 and GY2014G27
文摘The ear-shaped thermal front （ESTF）, formed by the convergence of the Yellow Sea Warm Current （YSWC） and the Shandong Coastal Current （SCC）, is a very important oceanic phenomenon in the Yellow Sea （YS） in winter. In situ measurements and reanalysis datasets all demonstrate that the ESTF has been weakening during 1950s-1990s, and a similar weakening trend is also found in winter monsoon over the YS. Numerical experiments show that the weakening of winter monsoon can induce an anomalous circulation in the YS on multi-decadal timescale with northward anomalous currents along China＇s coast and southward anomalous currents in the central YS--generally opposite to seasonal mean circulation. The anomalous circulation causes slowdown of the YSWC and the SCC, and thus weakens the ESTF. Since the ESTF plays important roles in regional ocean dynamics and air-sea interactions, its weakening has important implications for regional climate in the YS in winter.
文摘We analyze ten of the longest (127 to 230 year-long) time series of European daily temperatures available from five different Köppen-Geiger climate classes. We split these according to the level of solar cycle activity (H for “higher than median” and L for “lower than median”). This reveals coherent patterns in the temperature differences: when TH-TL?are stacked according to their calendar date, the daily averages from January 1 to December 31st disclose characteristic features in addition to the dominant annual seasonal wave, namely variations up to 2°C lasting for about 1.5 to 3 months. The five observatories at intermediate latitudes in a band from Oxford in the West to Prague in the East (same climate class) have very similar signatures. These similarities are most unlikely to be due to pure chance (confirmed by confidence levels in excess of 99% with the Kolmogorov-Smirnov and Kuiper nonparametric tests). The TH-TL patterns carry a regional signature, modulated by a more local response function. On the other hand, northern European observatories (St Petersburg and Arkhangelsk), those south of the Alps (Milan and Bologna), and the easternmost one in Astrakhan, corresponding to different climate classes, have different signatures. Similarly, preliminary study of long air pressure recordings confirms what emerges from the analysis of temperatures. These new observations lead us to conclude that the climate in different regions presents different responses to variations in solar activity. Moreover, the distributions of the lower, middle, and higher quartiles of the temperature and pressure indices in solar cycles with high versus low activity are significantly different, providing further robust statistical confirmation to this conclusion (confidence level higher to much higher than 99% using the Kuiper test).
基金supported by the National Basic Research Program of Chi-na (Grant No. 2011CB952000)the National Natural Science Founda-tion of China (Grant No. 40810059003)+1 种基金Qian Cheng was partly supported by the "Strategic Priority Research Program" of the Chinese Academy of Sciences (Grant No. XDA05090103)Wu Zhaohua was supported by the Natural Science Foundation of USA (Grant No. ATM-0917743)
文摘The Fourth Assessment Report (AR4) of the Intergovernmental Panel of Climate Change (IPCC) concluded that the climate projection using climate models that took account of both human and natural factors provided credible quantitative estimates of future climate change; however, the mismatches between the IPCC AR4 model ensembles and the observations, especially the multi-decadal variability (MDV), have cast shadows on the confidence of the model-based decadal projections of future cli mate. This paper reports an evaluation of many individual runs of AR4 models in the simulation of past global mean tempera ture. We find that most of the individual model runs fail to reproduce the MDV of past climate, which may have led to the overestimation of the projection of global warming for the next 40 years or so. Based on such an evaluation, we propose an al ternative approach, in which the MDV signal is taken into account, to project the global mean temperature for the next 40 years and obtain that the global warming during 2011–2050 could be much smaller than the AR4 projection.
