This paper analyzes the characteristics of super typhoons (STYs) over the western North Pacific (WNP) from 1965 to 2005 and describes the seasonal variability of STY activity. The relation between STY activity and...This paper analyzes the characteristics of super typhoons (STYs) over the western North Pacific (WNP) from 1965 to 2005 and describes the seasonal variability of STY activity. The relation between STY activity and the E1 Nifio-Southern Oscillation (ENSO) as well as the possible reason for the influence of the ENSO on STY activity are also investigated. The results showed that about one fifth of the tropical cyclones (TCs) over the WNP could reach the rank of STY. Most STYs appeared from July to November while there was a highest ratio between number of STYs and total number of TCs in November. Most STYs appeared east of the Philippine Sea. In E1 Nino years, affected by sea surface temperature (SST), monsoon trough and weak vertical wind shear, TC formation locations shifted eastward and there were more STYs than in La Nifia years when the affecting factors changed.展开更多
The intensity of interannual variability(IIV)of the monsoon and monsoon–ENSO biennial relationship(MEBR)were examined and compared for both the Indian summer monsoon(ISM)and western North Pacific summer monsoon(WNPSM...The intensity of interannual variability(IIV)of the monsoon and monsoon–ENSO biennial relationship(MEBR)were examined and compared for both the Indian summer monsoon(ISM)and western North Pacific summer monsoon(WNPSM)during 1958–2018.Covariability of the IIV and MEBR were identified for the two monsoons.When the MEBR was strong(weak),the IIV of the monsoon was observed to be large(small).This rule applied to both the ISM and WNPSM.Out-ofphase relationships were found between the ISM and the WNPSM.When the IIV and MEBR of the ISM were strong(weak),those of the WNPSM tended to be weak(strong).During the period with a stronger(weaker)ENSO–Atlantic coupling after(before)the mid-1980 s,the IIV and MEBR of the WNPSM(ISM)were observed to be stronger.The increasing influences from the tropical Atlantic sea surface temperature(SST)may trigger the observed seesaw pattern of the ISM and WNPSM in terms of the IIV and MEBR multidecadal variability.The results imply that tropical Atlantic SST may need to be given more attention and consideration when predicting future monsoon variability of the ISM and WNPSM.展开更多
Interannual variations of Pacific North Equatorial Current (NEC) transport during eastern- Pacific E1 Nifios (EP-EI Nifios) and central-Pacific E1 Nifios (CP-E1 Nifios) are investigated by composite analysis wit...Interannual variations of Pacific North Equatorial Current (NEC) transport during eastern- Pacific E1 Nifios (EP-EI Nifios) and central-Pacific E1 Nifios (CP-E1 Nifios) are investigated by composite analysis with European Centre for Medium-Range Weather Forecast Ocean Analysis/Reanalysis System 3. During EP-E1 Nifio, NEC transport shows significant positive anomalies from the developing to decay phases, with the largest anomalies around the mature phase. During CP-EI Nifio, however, the NEC transport only shows positive anomalies before the mature phase, with much weaker anomalies than those during EP-El Nifio. The NEC transport variations are strongly associated with variations of the tropical gyre and wind forcing in the tropical North Pacific. During EP-E1 Nifio, strong westerly wind anomalies and positive wind stress curl anomalies in the tropical North Pacific induce local upward Ekman pumping and westward-propagating upwelling Rossby waves in the ocean, lowering the sea surface height and generating a cyclonic gyre anomaly in the western tropical Pacific. During CP-E1 Nifio, however, strength of the wind and associated Ekman pumping velocity are very weak. Negative sea surface height and cyclonic flow anomalies are slightly north of those during EP El Nino.展开更多
Previous studies have revealed a connection between springtime sea surface temperature (SST) in the tropical northern Atlantic (TNA) and the succeeding wintertime El Nino-Southern Oscillation (ENSO). The present...Previous studies have revealed a connection between springtime sea surface temperature (SST) in the tropical northern Atlantic (TNA) and the succeeding wintertime El Nino-Southern Oscillation (ENSO). The present analysis demonstrates that the linkage between springtime TNA SST and the following ENSO experiences an obvious interdecadal change around the early 1980s, with the connection being weak before but significant after. After the early 1980s, springtime positive TNA SST anomalies induce an anomalous cyclone over the northeastern subtropical Pacific and an anomalous Walker circulation with a descending branch over the tropical central-eastern Pacific. This leads to anomalous cold SST in the northeastern Pacific and an anomalous anticyclone over the western-central tropical Pacific, with anomalous easterlies to the equatorward side. As such, springtime TNA SST anomalies are followed by wintertime ENSO after the early 1980s. In contrast, before the early 1980s, anomalous cold SST in the northeastern Pacific and related anomalous easterlies over the western-central tropical Pacific are weak, corresponding to springtime positive TNA SST anomalies and resulting in a weak linkage between springtimeTNA SST and the succeeding wintertime ENSO. Further investigation implies that the change in the TNA SST-ENSO relationship is probably due to a change in springtime mean precipitation over the tropical Atlantic and South America.展开更多
The climate modulation on the sea surface height (SSH) in China seas is investigated using a China Ocean Reanalysis (CORA) dataset from 1958-2008. The dataset is constructed by assimilating the temperature/salinit...The climate modulation on the sea surface height (SSH) in China seas is investigated using a China Ocean Reanalysis (CORA) dataset from 1958-2008. The dataset is constructed by assimilating the temperature/salinity profiles derived from the satellite altimetry data and historical observational temperature/salinity profiles. Based on the Empirical Orthogonal Function (EOF), the CORA sea surface height anomaly (SSHa) is decomposed, and the interannual and decadal variability of the first three leading modes are analyzed. On the interannual timescale, the first principal component (PC1) is significant positively correlated with the E1 Nifio/Southern Oscillation (ENSO). On the decadal timescale, North Pacific Gyre Oscillation (NPGO) has significant negative correlation with PC 1 whereas Pacific Decadal Oscillation (PDO) is in phase with PC3. Analysis shows that the decadal variability of SSH is mainly modulated by the wind stress curl variability related to the NPGO and PDO. In addition, the effect of net heat flux associated to the NPGO and PDO on SSH is also investigated, with net heat flux variability in the Luzon strait and tropic Pacific found to influence the decadal variability of SSH.展开更多
Recent SST and atmospheric circulation anomaly data suggest that the 2015/16 El Nino event is quickly decaying. Some researchers have predicted a forthcoming La Nina event in late summer or early fall 2016. From the p...Recent SST and atmospheric circulation anomaly data suggest that the 2015/16 El Nino event is quickly decaying. Some researchers have predicted a forthcoming La Nina event in late summer or early fall 2016. From the perspective of the modulation of tropical SST by solar activity, the authors studied the evolution of the 2015/16 El Nino event, which occurred right after the 2014 solar peak year. Based on statistical and composite analysis, a significant positive correlation was found between sunspot number index and El Ni^o Modoki index, with a lag of two years. A clear evolution of El Nino Modoki events was found within 1-3 years following each solar peak year during the past 126 years, suggesting that anomalously strong solar activity during solar peak periods favors the triggering of an El Nino Modoki event. The patterns of seasonal mean SST and wind anomalies since 2014 are more like a mixture of two types of El Nino (i.e. eastern Pacific El Nino and El Nino Modoki), which is similar to the pattern modulated by solar activity during the years following a solar peak. Therefore, the El Nino Modoki component in the 2015/16 El Nino event may be a consequence of solar activity, which probably will not decay as quickly as the eastern Pacific El Nino component. The positive SST anomaly will probably sustain in the central equatorial Pacific (around the dateline) and the northeastern Pacific along the coast of North America, with a low-intensity level, during the second half of 2016.展开更多
This study investigates the combined effect of the El Nino–Southern Oscillation(ENSO) and stratospheric quasi-biennial oscillation(QBO) on the Madden Julian Oscillation(MJO). The results show that the western Pacific...This study investigates the combined effect of the El Nino–Southern Oscillation(ENSO) and stratospheric quasi-biennial oscillation(QBO) on the Madden Julian Oscillation(MJO). The results show that the western Pacific MJO originating from the Indian Ocean during La Nina/QBO easterly years is stronger than that during El Nino years. This relation, however, disappears during La Nina/QBO westerly years. The reason is that ENSO and the QBO have different effects on each MJO event. For an El Nino year, there is only about one MJO event, and the QBO effect is small. During a La Nina/QBO easterly year, there are 1.7 MJO events, while during a La Nina/QBO westerly year, there are only 0.6 MJO events. El Nino can reinforce the MJO over the western Pacific because of the positive moisture advection of the El Nino mean state by MJO easterly wind anomalies. The QBO mainly affects the MJO over the Maritime Continent region by changing the high-cloud-controlled diurnal cycle;and the Maritime Continent barrier effect is enhanced during the QBO westerly phase because of the strong diurnal cycle. During El Nino years, even the MJO over the Maritime Continent is suppressed by the QBO westerly phase;the MJO can be reinforced over the western Pacific. During La Nina/QBO westerly years,the MJO over the Maritime Continent is suppressed because of the strong Maritime Continent diurnal cycle, and it is further suppressed over the western Pacific because of the lack of a reinforcement process.展开更多
There is a rainfall variability biennial relationship between Central America (CA) and equatorial South America (ESA) over the tropical western hemisphere, which is known to have arisen due to the combined effects...There is a rainfall variability biennial relationship between Central America (CA) and equatorial South America (ESA) over the tropical western hemisphere, which is known to have arisen due to the combined effects of ENSO and tropical North Atlantic (TNA) SST. Here, the authors report that this biennial rainfall relationship between CA and ESA has weakened remarkably since 2000, with weakening in both in-phase and out-of-phase rainfall transitions. The observed decadal changes in the biennial relationship between CA and ESA rainfall can be attributed to changes in the effects of ENSO and TNA SST since 2000, which may be associated with more frequent occurrences of the central Pacific or'Modoki' type El Ni^o. The weakening of the association with ENSO for CA rainfall since 2000 might have given rise to the weakening of the in-phase rain transition from CA rainfall to the following ESA rainfall. The weakened linkage between boreal-winter ESA rainfall and the subsequent boreal-summer TNA SST since 2000 may have resulted in the weakening of the out- of-phase rainfall transition from boreal-winter ESA rainfall to the subsequent boreal-summer CA rainfall.展开更多
Based on the study of the cold phase of the Pacific Decade Oscillation, pandemic influenza is related to climate. The relation of low temperature, Pacific Decade Oscillation, strongest earthquake, Influenza, hurricane...Based on the study of the cold phase of the Pacific Decade Oscillation, pandemic influenza is related to climate. The relation of low temperature, Pacific Decade Oscillation, strongest earthquake, Influenza, hurricane and E1 Nino is researched in this study. In the cold period of Pacific Decade Oscillation, the strongest earthquake, hurricane with La Ni'na, Pandemic Influenza with E1 Nino will occur stronger and stronger. From 1950 to 1976, the strongest dust-storm is connected with Pandemic Influenza one by one. So, dust-storm is one of factors to spread pandemic influenza viruses.展开更多
Equatorial central Pacific precipitation experienced a prominent decline in the late 1990 s.This change was previously attributed to a La Nina-like mean sea surface temperature(SST)change in the Pacific Ocean associat...Equatorial central Pacific precipitation experienced a prominent decline in the late 1990 s.This change was previously attributed to a La Nina-like mean sea surface temperature(SST)change in the Pacific Ocean associated with a phase switch of the Interdecadal Pacific Oscillation.Here,using a series of model experiments,the authors reveal that the El Nino-related interannual SST anomalies contributed largely to the precipitation decrease over the equatorial central Pacific.This El Nino SST effect was due to the change in the amplitude of El Nino events in the late 1990 s.The 1980-98 decade had more large-amplitude El Nino events than the 1999-2014 decade.The nonlinear precipitation response to SST anomalies resulted in a larger decadal mean precipitation in the 1980-98 decade than in the 1999-2014 decade.The results highlight the importance of El Nino amplitude change in future climate change related to global warming.展开更多
Both the tropical Indian and tropical Pacific Oceans are active atmosphere-ocean interactive regions with robust interannual variability, which also constitutes a linkage between the two basins in the mode of variabil...Both the tropical Indian and tropical Pacific Oceans are active atmosphere-ocean interactive regions with robust interannual variability, which also constitutes a linkage between the two basins in the mode of variability. Using a global atmosphere- ocean coupled model, we conducted two experiments (CTRL and PC) to explore the contributions of Indian Ocean interannual sea surface temperature (SST) modes to the occurrence of E1 Nino events. The results show that interannual variability of the SST in the Indian Ocean induces a rapid growth of E1 Nino events during the boreal autumn in an E1 Nino developing year. However, it weakens E1 Nino events or even promotes cold phase conversions in an E1 Nino decaying year. Therefore, the en- tire period of the E1 Nino is shortened by the interannual variations of the Indian Ocean SST. Specifically, during the E1 Nino developing years, the positive Indian Ocean Dipole (IOD) events force an anomalous Walker circulation, which then enhances the existing westerly wind anomalies over the west Pacific. This will cause a warmer E1 Nino event, with some modulations by ocean advection and oceanic Rossby and Kelvin waves. However, with the onset of the South Asian monsoon, the Indian Ocean Basin (IOB) warming SST anomalies excite low level easterly wind anomalies over the west tropical Pacific during the El Nino decaying years. As a result, the E1 Nino event is prompted to change from a warm phase to a cold phase. At the same time, an associated atmospheric anticyclone anomaly appears and leads to a decreasing precipitation anomaly over the northwest Pacific. In summary, with remote forcing in the atmospheric circulation, the IOD mode usually affects the E1 Nino during the developing years, whereas the IOB mode affects the E1 Nino during the decaying years.展开更多
We applied a season-reliant empirical orthogonal function(S-EOF) analysis based on the results of the Community Earth System Model, version 1-Biogeochemistry, to seasonal mean air-sea CO_2 flux over the western North ...We applied a season-reliant empirical orthogonal function(S-EOF) analysis based on the results of the Community Earth System Model, version 1-Biogeochemistry, to seasonal mean air-sea CO_2 flux over the western North Pacific(WNP)(0°–35°N, 110°E–150°E). The first leading mode accounts for 29% of the total interannual variance, corresponding to the evolution of the El Ni-Southern Oscillation(ENSO) from its developing to decaying phases. During the ENSO developing phase in the summer and fall, the contribution of surface seawater CO_2 partial pressure anomalies is greater than that of gas transfer/solubility anomalies, which contribute to increasing oceanic CO_2 uptake over the WNP. During the ENSO mature phase in the winter, the anomalous southwesterly northwest of the western North Pacific anticyclone(WNPAC) reduces the surface wind speed in the China marginal sea and thus decreases oceanic CO_2 uptake by reducing the gas transfer coefficient. In the subsequent spring, the WNPAC maintains with an eastward shift in position. The anomalous southwesterly warms sea surface temperatures in the China marginal sea by reducing evaporation and thus decreases oceanic CO_2 uptake by enhancing surface seawater CO_2 partial pressure. This process, rather than the effect of decreasing gas transfer coefficient, dominates CO_2 flux anomalies in the spring.展开更多
Based on the merged satellite altimeter data and in-situ observations, as well as a diagnosis of linear baroclinic Rossby wave solutions, this study analyzed the rapidly rise of sea level/sea surface height (SSH) in...Based on the merged satellite altimeter data and in-situ observations, as well as a diagnosis of linear baroclinic Rossby wave solutions, this study analyzed the rapidly rise of sea level/sea surface height (SSH) in the tropical Pacific and Indian Oceans during recent two decades. Results show that the sea level rise signals in the tropical west Pacific and the southeast Indian Ocean are closely linked to each other through the pathways of oceanic waveguide within the Indonesian Seas in the form of thermocline adjustment. The sea level changes in the southeast Indian Ocean are strongly influenced by the low-frequency westward-propagating waves originated in the tropical Pacific, whereas those in the southwest Indian Ocean respond mainly to the local wind forcing. Analyses of the lead-lag correlation further reveal the different origins of interannual and interdecadal variabilities in the tropical Pacific. The interannual wave signals are dominated by the wind variability along the equatorial Pa- cific, which is associated with the El Nifio-Southern Oscillation; whereas the interdecadal signals are driven mainly by the wind curl off the equatorial Pacific, which is closely related to the Pacific Decadal Oscillation.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.s 40975038 and10735030)the State Key Development Program for Basic Research of China(973 Program)(Grant Nos.2006CB403603 and 2005CB422301)111 Project(Grant No.B07036)
文摘This paper analyzes the characteristics of super typhoons (STYs) over the western North Pacific (WNP) from 1965 to 2005 and describes the seasonal variability of STY activity. The relation between STY activity and the E1 Nifio-Southern Oscillation (ENSO) as well as the possible reason for the influence of the ENSO on STY activity are also investigated. The results showed that about one fifth of the tropical cyclones (TCs) over the WNP could reach the rank of STY. Most STYs appeared from July to November while there was a highest ratio between number of STYs and total number of TCs in November. Most STYs appeared east of the Philippine Sea. In E1 Nino years, affected by sea surface temperature (SST), monsoon trough and weak vertical wind shear, TC formation locations shifted eastward and there were more STYs than in La Nifia years when the affecting factors changed.
基金supported by the National Natural Science Foundation of China grant number 41776031the National Key Research and Development Program of China grant number 2018YFC1506903+2 种基金the Guangdong Natural Science Foundation grant number 2015A030313796the program for scientific research start-up funds of Guangdong Ocean Universitythe Foundation for Returned Scholars of the Ministry of Education of China。
文摘The intensity of interannual variability(IIV)of the monsoon and monsoon–ENSO biennial relationship(MEBR)were examined and compared for both the Indian summer monsoon(ISM)and western North Pacific summer monsoon(WNPSM)during 1958–2018.Covariability of the IIV and MEBR were identified for the two monsoons.When the MEBR was strong(weak),the IIV of the monsoon was observed to be large(small).This rule applied to both the ISM and WNPSM.Out-ofphase relationships were found between the ISM and the WNPSM.When the IIV and MEBR of the ISM were strong(weak),those of the WNPSM tended to be weak(strong).During the period with a stronger(weaker)ENSO–Atlantic coupling after(before)the mid-1980 s,the IIV and MEBR of the WNPSM(ISM)were observed to be stronger.The increasing influences from the tropical Atlantic sea surface temperature(SST)may trigger the observed seesaw pattern of the ISM and WNPSM in terms of the IIV and MEBR multidecadal variability.The results imply that tropical Atlantic SST may need to be given more attention and consideration when predicting future monsoon variability of the ISM and WNPSM.
基金Supported by the National Basic Research Program of China(973 Program)(Nos.2012CB417401,2013CB956202)the Key Project of National Natural Science Foundation of China(No.41330963)the Fundamental Research Funds for the Central Universities(No.201513030)
文摘Interannual variations of Pacific North Equatorial Current (NEC) transport during eastern- Pacific E1 Nifios (EP-EI Nifios) and central-Pacific E1 Nifios (CP-E1 Nifios) are investigated by composite analysis with European Centre for Medium-Range Weather Forecast Ocean Analysis/Reanalysis System 3. During EP-E1 Nifio, NEC transport shows significant positive anomalies from the developing to decay phases, with the largest anomalies around the mature phase. During CP-EI Nifio, however, the NEC transport only shows positive anomalies before the mature phase, with much weaker anomalies than those during EP-El Nifio. The NEC transport variations are strongly associated with variations of the tropical gyre and wind forcing in the tropical North Pacific. During EP-E1 Nifio, strong westerly wind anomalies and positive wind stress curl anomalies in the tropical North Pacific induce local upward Ekman pumping and westward-propagating upwelling Rossby waves in the ocean, lowering the sea surface height and generating a cyclonic gyre anomaly in the western tropical Pacific. During CP-E1 Nifio, however, strength of the wind and associated Ekman pumping velocity are very weak. Negative sea surface height and cyclonic flow anomalies are slightly north of those during EP El Nino.
基金supported by the National Natural Science Foundation of China[grant numbers 41530425 and 41605050]the China Postdoctoral Science Foundation[grant number2015M581151]
文摘Previous studies have revealed a connection between springtime sea surface temperature (SST) in the tropical northern Atlantic (TNA) and the succeeding wintertime El Nino-Southern Oscillation (ENSO). The present analysis demonstrates that the linkage between springtime TNA SST and the following ENSO experiences an obvious interdecadal change around the early 1980s, with the connection being weak before but significant after. After the early 1980s, springtime positive TNA SST anomalies induce an anomalous cyclone over the northeastern subtropical Pacific and an anomalous Walker circulation with a descending branch over the tropical central-eastern Pacific. This leads to anomalous cold SST in the northeastern Pacific and an anomalous anticyclone over the western-central tropical Pacific, with anomalous easterlies to the equatorward side. As such, springtime TNA SST anomalies are followed by wintertime ENSO after the early 1980s. In contrast, before the early 1980s, anomalous cold SST in the northeastern Pacific and related anomalous easterlies over the western-central tropical Pacific are weak, corresponding to springtime positive TNA SST anomalies and resulting in a weak linkage between springtimeTNA SST and the succeeding wintertime ENSO. Further investigation implies that the change in the TNA SST-ENSO relationship is probably due to a change in springtime mean precipitation over the tropical Atlantic and South America.
基金Supported by the National Basic Research Program of China(973 Program)(No.2013CB430304)the National Natural Science Foundation of China(Nos.41176003,41206178,41376013,41376015,41306006)+1 种基金the National High Technology Research and Development Program of China(863 Program)(No.2013AA09A505)the Global Change and Air-Sea Interaction of China(No.GASI-01-01-12)
文摘The climate modulation on the sea surface height (SSH) in China seas is investigated using a China Ocean Reanalysis (CORA) dataset from 1958-2008. The dataset is constructed by assimilating the temperature/salinity profiles derived from the satellite altimetry data and historical observational temperature/salinity profiles. Based on the Empirical Orthogonal Function (EOF), the CORA sea surface height anomaly (SSHa) is decomposed, and the interannual and decadal variability of the first three leading modes are analyzed. On the interannual timescale, the first principal component (PC1) is significant positively correlated with the E1 Nifio/Southern Oscillation (ENSO). On the decadal timescale, North Pacific Gyre Oscillation (NPGO) has significant negative correlation with PC 1 whereas Pacific Decadal Oscillation (PDO) is in phase with PC3. Analysis shows that the decadal variability of SSH is mainly modulated by the wind stress curl variability related to the NPGO and PDO. In addition, the effect of net heat flux associated to the NPGO and PDO on SSH is also investigated, with net heat flux variability in the Luzon strait and tropic Pacific found to influence the decadal variability of SSH.
基金supported by the National Basic Research Program of china(973 Program)[grant number 2012c B957804]the External cooperation Program of BIc,chinese Academy of Sciences[grant number 134111KYSB20150016]
文摘Recent SST and atmospheric circulation anomaly data suggest that the 2015/16 El Nino event is quickly decaying. Some researchers have predicted a forthcoming La Nina event in late summer or early fall 2016. From the perspective of the modulation of tropical SST by solar activity, the authors studied the evolution of the 2015/16 El Nino event, which occurred right after the 2014 solar peak year. Based on statistical and composite analysis, a significant positive correlation was found between sunspot number index and El Ni^o Modoki index, with a lag of two years. A clear evolution of El Nino Modoki events was found within 1-3 years following each solar peak year during the past 126 years, suggesting that anomalously strong solar activity during solar peak periods favors the triggering of an El Nino Modoki event. The patterns of seasonal mean SST and wind anomalies since 2014 are more like a mixture of two types of El Nino (i.e. eastern Pacific El Nino and El Nino Modoki), which is similar to the pattern modulated by solar activity during the years following a solar peak. Therefore, the El Nino Modoki component in the 2015/16 El Nino event may be a consequence of solar activity, which probably will not decay as quickly as the eastern Pacific El Nino component. The positive SST anomaly will probably sustain in the central equatorial Pacific (around the dateline) and the northeastern Pacific along the coast of North America, with a low-intensity level, during the second half of 2016.
基金supported by the National Natural Science Foundation of China [grant number 41420104002]the China National 973 Project [grant number 2015CB453200]+2 种基金the Public Science and Technology Research Funds Projects of the Ocean[grant number 201505013]the Natural Science Foundation of Jiangsu Province [grant numbers BK20150907 and 14KJA170002]the National Science Foundation of the US [grant number AGS-1540783]
文摘This study investigates the combined effect of the El Nino–Southern Oscillation(ENSO) and stratospheric quasi-biennial oscillation(QBO) on the Madden Julian Oscillation(MJO). The results show that the western Pacific MJO originating from the Indian Ocean during La Nina/QBO easterly years is stronger than that during El Nino years. This relation, however, disappears during La Nina/QBO westerly years. The reason is that ENSO and the QBO have different effects on each MJO event. For an El Nino year, there is only about one MJO event, and the QBO effect is small. During a La Nina/QBO easterly year, there are 1.7 MJO events, while during a La Nina/QBO westerly year, there are only 0.6 MJO events. El Nino can reinforce the MJO over the western Pacific because of the positive moisture advection of the El Nino mean state by MJO easterly wind anomalies. The QBO mainly affects the MJO over the Maritime Continent region by changing the high-cloud-controlled diurnal cycle;and the Maritime Continent barrier effect is enhanced during the QBO westerly phase because of the strong diurnal cycle. During El Nino years, even the MJO over the Maritime Continent is suppressed by the QBO westerly phase;the MJO can be reinforced over the western Pacific. During La Nina/QBO westerly years,the MJO over the Maritime Continent is suppressed because of the strong Maritime Continent diurnal cycle, and it is further suppressed over the western Pacific because of the lack of a reinforcement process.
基金funded by the National Natural Science Foundation of China[grant number 41776031]the Guangdong Natural Science Foundation[grant number 2015A030313796]+3 种基金the National Program on Global Change and Air-Sea Interaction[grant number GASI-IPOVAI-04]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA11010104]the program for scientific research start-upfunds of Guangdong Ocean Universitythe Foundation for Returned Scholars of the Ministry of Education of China
文摘There is a rainfall variability biennial relationship between Central America (CA) and equatorial South America (ESA) over the tropical western hemisphere, which is known to have arisen due to the combined effects of ENSO and tropical North Atlantic (TNA) SST. Here, the authors report that this biennial rainfall relationship between CA and ESA has weakened remarkably since 2000, with weakening in both in-phase and out-of-phase rainfall transitions. The observed decadal changes in the biennial relationship between CA and ESA rainfall can be attributed to changes in the effects of ENSO and TNA SST since 2000, which may be associated with more frequent occurrences of the central Pacific or'Modoki' type El Ni^o. The weakening of the association with ENSO for CA rainfall since 2000 might have given rise to the weakening of the in-phase rain transition from CA rainfall to the following ESA rainfall. The weakened linkage between boreal-winter ESA rainfall and the subsequent boreal-summer TNA SST since 2000 may have resulted in the weakening of the out- of-phase rainfall transition from boreal-winter ESA rainfall to the subsequent boreal-summer CA rainfall.
文摘Based on the study of the cold phase of the Pacific Decade Oscillation, pandemic influenza is related to climate. The relation of low temperature, Pacific Decade Oscillation, strongest earthquake, Influenza, hurricane and E1 Nino is researched in this study. In the cold period of Pacific Decade Oscillation, the strongest earthquake, hurricane with La Ni'na, Pandemic Influenza with E1 Nino will occur stronger and stronger. From 1950 to 1976, the strongest dust-storm is connected with Pandemic Influenza one by one. So, dust-storm is one of factors to spread pandemic influenza viruses.
基金supported by the National Key Research and Development Program of China [grant number2016YFA0600603]the National Natural Science Foundation of China [grant numbers 41775080,41530425,41721004,and 41475081]
文摘Equatorial central Pacific precipitation experienced a prominent decline in the late 1990 s.This change was previously attributed to a La Nina-like mean sea surface temperature(SST)change in the Pacific Ocean associated with a phase switch of the Interdecadal Pacific Oscillation.Here,using a series of model experiments,the authors reveal that the El Nino-related interannual SST anomalies contributed largely to the precipitation decrease over the equatorial central Pacific.This El Nino SST effect was due to the change in the amplitude of El Nino events in the late 1990 s.The 1980-98 decade had more large-amplitude El Nino events than the 1999-2014 decade.The nonlinear precipitation response to SST anomalies resulted in a larger decadal mean precipitation in the 1980-98 decade than in the 1999-2014 decade.The results highlight the importance of El Nino amplitude change in future climate change related to global warming.
基金supported by the National Basic Research Program of China(Grant Nos.2010CB428504,2012CB956002)the National Natural Science Foundation of China(Grant Nos.40906005,41105059,41065005,GYHY2011-06017,GYHY201306027)+1 种基金the National Key Technologies R&D Program of China(Grant No.2009BAC51B01)the Jiangsu Collaborative Innovation Center for Climate Change
文摘Both the tropical Indian and tropical Pacific Oceans are active atmosphere-ocean interactive regions with robust interannual variability, which also constitutes a linkage between the two basins in the mode of variability. Using a global atmosphere- ocean coupled model, we conducted two experiments (CTRL and PC) to explore the contributions of Indian Ocean interannual sea surface temperature (SST) modes to the occurrence of E1 Nino events. The results show that interannual variability of the SST in the Indian Ocean induces a rapid growth of E1 Nino events during the boreal autumn in an E1 Nino developing year. However, it weakens E1 Nino events or even promotes cold phase conversions in an E1 Nino decaying year. Therefore, the en- tire period of the E1 Nino is shortened by the interannual variations of the Indian Ocean SST. Specifically, during the E1 Nino developing years, the positive Indian Ocean Dipole (IOD) events force an anomalous Walker circulation, which then enhances the existing westerly wind anomalies over the west Pacific. This will cause a warmer E1 Nino event, with some modulations by ocean advection and oceanic Rossby and Kelvin waves. However, with the onset of the South Asian monsoon, the Indian Ocean Basin (IOB) warming SST anomalies excite low level easterly wind anomalies over the west tropical Pacific during the El Nino decaying years. As a result, the E1 Nino event is prompted to change from a warm phase to a cold phase. At the same time, an associated atmospheric anticyclone anomaly appears and leads to a decreasing precipitation anomaly over the northwest Pacific. In summary, with remote forcing in the atmospheric circulation, the IOD mode usually affects the E1 Nino during the developing years, whereas the IOB mode affects the E1 Nino during the decaying years.
基金supported by the National Natural Science Foundation of China(Grant Nos.41330423,41420104006)Jiangsu Collaborative Innovation Center for Climate Change
文摘We applied a season-reliant empirical orthogonal function(S-EOF) analysis based on the results of the Community Earth System Model, version 1-Biogeochemistry, to seasonal mean air-sea CO_2 flux over the western North Pacific(WNP)(0°–35°N, 110°E–150°E). The first leading mode accounts for 29% of the total interannual variance, corresponding to the evolution of the El Ni-Southern Oscillation(ENSO) from its developing to decaying phases. During the ENSO developing phase in the summer and fall, the contribution of surface seawater CO_2 partial pressure anomalies is greater than that of gas transfer/solubility anomalies, which contribute to increasing oceanic CO_2 uptake over the WNP. During the ENSO mature phase in the winter, the anomalous southwesterly northwest of the western North Pacific anticyclone(WNPAC) reduces the surface wind speed in the China marginal sea and thus decreases oceanic CO_2 uptake by reducing the gas transfer coefficient. In the subsequent spring, the WNPAC maintains with an eastward shift in position. The anomalous southwesterly warms sea surface temperatures in the China marginal sea by reducing evaporation and thus decreases oceanic CO_2 uptake by enhancing surface seawater CO_2 partial pressure. This process, rather than the effect of decreasing gas transfer coefficient, dominates CO_2 flux anomalies in the spring.
基金supported by the "Strategic Priority Research Program" of the Chinese Academy of Sciences (Grant No. XDA11010103)the National Basic Research Program of China (Grant Nos. 2012CB955603, 2010CB950302)+1 种基金National Natural Science Foundation of China (Grant Nos. 41176024, 41176028)supported by the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘Based on the merged satellite altimeter data and in-situ observations, as well as a diagnosis of linear baroclinic Rossby wave solutions, this study analyzed the rapidly rise of sea level/sea surface height (SSH) in the tropical Pacific and Indian Oceans during recent two decades. Results show that the sea level rise signals in the tropical west Pacific and the southeast Indian Ocean are closely linked to each other through the pathways of oceanic waveguide within the Indonesian Seas in the form of thermocline adjustment. The sea level changes in the southeast Indian Ocean are strongly influenced by the low-frequency westward-propagating waves originated in the tropical Pacific, whereas those in the southwest Indian Ocean respond mainly to the local wind forcing. Analyses of the lead-lag correlation further reveal the different origins of interannual and interdecadal variabilities in the tropical Pacific. The interannual wave signals are dominated by the wind variability along the equatorial Pa- cific, which is associated with the El Nifio-Southern Oscillation; whereas the interdecadal signals are driven mainly by the wind curl off the equatorial Pacific, which is closely related to the Pacific Decadal Oscillation.