The characteristics of the summer precipitation diurnal cycle over South Asia and East Asia during 2001–13 are investigated based on the high spatiotemporal resolution estimates of the CPC(Climate Prediction Center) ...The characteristics of the summer precipitation diurnal cycle over South Asia and East Asia during 2001–13 are investigated based on the high spatiotemporal resolution estimates of the CPC(Climate Prediction Center) Morphing(CMORPH) technique. The results show that summer precipitation over South Asia and East Asia possesses a remarkable diurnal cycle, with obvious regional differences. Over the coastal areas, plateau, and high mountains, summer precipitation peaks in the late afternoon; while over low altitude areas, such as valleys, basins, and inshore seas, it peaks during midnight to early morning. In addition to these general features consistent with previous studies, the high resolution CMORPH technique can depict finer regional details, such as the less coherent phase pattern over a few regions. Besides, through comparative analysis of the diurnal cycle strength and precipitation fields, the authors find that for humid areas the summer precipitation diurnal cycle is especially significant over Southeast China, the Sichuan Basin, Hainan Province, Taiwan Province, the Philippines, and Indonesia. And it is relatively weak over the south of Northeast China, central East China, Yunnan Province, the central Indian Peninsula, and most oceanic areas. Comparisons between two satellite datasets—those of the CMORPH and Tropical Rainfall Measuring Mission(TRMM) 3B42 products—are also presented. For summer precipitation and the main diurnal cycle features, the results from both products agree over most regions, except a few areas, e.g., the Tibetan Plateau.展开更多
It is well known that precipitation anomalies in the tropical western North Pacific (WNP) significantly affect circulation and rainfall in East Asia during summer. In this study, the authors further investigated thi...It is well known that precipitation anomalies in the tropical western North Pacific (WNP) significantly affect circulation and rainfall in East Asia during summer. In this study, the authors further investigated this relationship, by examining the anomalies associated with positive and negative precipitation anomalies in the tropical WNP. The results suggest these anomalies are asymmetric between the enhanced and suppressed WNP rainfall. Positive precipitation anomalies over the WNP, in comparison with their negative counterparts, are more closely related to the meridional teleconnection pattern and rainfall anomalies along the East Asian rain belt. The implications of the results are discussed.展开更多
In this study, the authors simulate the East Asian climate changes in the mid-Pliocene (~3.3 to 3.0 Ma BP) with the Community Atmosphere Model version 3.1 (CAM3.1) and compare the simulated East Asian monsoon with pa...In this study, the authors simulate the East Asian climate changes in the mid-Pliocene (~3.3 to 3.0 Ma BP) with the Community Atmosphere Model version 3.1 (CAM3.1) and compare the simulated East Asian monsoon with paleoclimate data. The simulations show an obvious warming pattern in East Asia in the mid-Pliocene compared with the pre-industrial climate, with surface air temperature increasing by 0.5 4.0°C. In the warm mid-Pliocene simulation, the East Asian Summer Monsoon (EASM) becomes stronger, while the East Asian Winter Monsoon (EAWM) is similar relative to the pre-industrial climate. Compared with the paleoclimate data, our simulations depict the intensified EASM well but cannot reproduce the weakened EAWM. This model-data discrepancy may be attributed to the uncertainty in the reconstructed mid-Pliocene sea surface temperature.展开更多
The first two series(RMM1 and RMM2) of RMM Index(all-Season Real-time Multivariate MJO Index) are computed to obtain the interannual variation of the preceding winter(preceding December to current February) MJO streng...The first two series(RMM1 and RMM2) of RMM Index(all-Season Real-time Multivariate MJO Index) are computed to obtain the interannual variation of the preceding winter(preceding December to current February) MJO strength,according to which active(or inactive) years of preceding winter MJO are divided.By utilizing the data provided by NCEP/NCAR,CMAP and China's 160 stations from 1979 to 2008,we studied the preceding winter MJO strength and discovered that the summer precipitation in the basin are of significantly negative correlation,i.e.when the preceding winter MJO is relatively active,the summer precipitation in the basin decreases,and vise verse.We also analyzed the causes.When the preceding winter MJO is relatively active,its release of potential heat facilities Inter-Tropical Convergence Zone(ITCZ) to strengthen and locate northward in winter and propagate northeastward.This abnormal situation lasts from winter to summer.In mid-May,ITCZ jumps northward to the South China Sea,the western Pacific subtropical high withdraws eastward,and the South China Sea summer monsoon sets off and strengthens.In summer,ITCZ propagates to South China Sea-subtropical western Pacific,the zonal circulation of subtropical Pacific strengthens,and a local meridional circulation of the South China Sea to the basin area forms,giving rise to the East Asia Pacific teleconnection wave-train.An East Asian monsoon trough and the Meiyu front show opposite features from south to north,the East Asian summer monsoon strengthens and advances northward.As a result,the summer monsoon is weakened as the basin is controlled by the subtropical high continually,with less rain in summer.On the contrary,when the preceding winter MJO is inactive,ITCZ weakens and is located southward,the subtropical high is located southward in summer,and the basin is in a region of ascending airflow with prevailing southwest wind.The East Asian monsoon trough and EASM weaken so that summer monsoon is reduced in the basin where precipitation increases.展开更多
The East Asian westerly jet(EAJ)plays a crucial role in affecting the East Asian summer rainfall(EASR).Therefore,evaluations of EAJ simulations are vital for improving the understanding and projections of climate chan...The East Asian westerly jet(EAJ)plays a crucial role in affecting the East Asian summer rainfall(EASR).Therefore,evaluations of EAJ simulations are vital for improving the understanding and projections of climate change in East Asia.This study evaluates the simulations of the climatology and interannual variability in the present-day summer EAJ in the CMIP6 models and compares the results with those in the CMIP5 models by analyzing the historical climate simulations of 29 CMIP5 models and 21 CMIP6 models during the period from 1986–2005.In general,the CMIP6 models capture the EAJ more realistically than the CMIP5 models.The results show that the CMIP6 models reasonably capture the spatial features of the climatological zonal wind at 200 hPa and simulate a smaller zonal wind bias along the EAJ.The locations of the EAJ’s core are at the observed location in nearly all CMIP6 models but in only approximately two-thirds of the CMIP5 models.The EAJ’s intensity is closer to the observed value and exhibits a smaller intermodel dispersion in the CMIP6 models.The CMIP6 models also show an improved ability to reproduce the interannual variability in the EAJ’s meridional displacement and have a stronger relationship with the EASR.展开更多
This study reveals a significant relationship, on the interannual timescale, between a dipole mode, the second leading mode, of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asi...This study reveals a significant relationship, on the interannual timescale, between a dipole mode, the second leading mode, of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asia. Related to the dipole mode, with the heavier sea ice in the north and lighter sea ice in the southeast Barents Sea in spring, the East Asian summer subtropical rainy belt tends to move northward. The significant relationship is established through a wave train over northern Eurasia in the lower troposphere in June. The wave train enhances the northern East Asian low, which induces more rainfall to the north of the East Asian subtropical rainy belt and then attracts the subtropical rainy belt to move northward. This study suggests that the dipole mode of spring sea-ice anomalies in the Barents Sea may be a good precursor for the prediction of East Asian summer rainfall.展开更多
To understand the provenance and evolution of eolian input in the last 1.95 Ma in the Parece Vela Basin in the eastern Philippine Sea, the clay mineral assemblage of a gravity core PV090510 from the basin was investig...To understand the provenance and evolution of eolian input in the last 1.95 Ma in the Parece Vela Basin in the eastern Philippine Sea, the clay mineral assemblage of a gravity core PV090510 from the basin was investigated using paleogeomagnetic dating and X-ray diffraction. The assemblage of the core mainly consisted of smectite (-46%) and illite (-40%), with some chlorite (-10%) and kaolinite (-4%). Analysis of the provenance of these minerals suggested that smectite was mainly derived from volcanic rocks of the Mariana Arc, while illite, chlorite, and kaolinite were mainly transported as eolian dust by the East Asian monsoon from central Asia. We used the ratio of (illite+chlorite+kaolinite)/smectite as a proxy for Asian eolian input to the Parece Vela Basin since 1.95 Ma. This ratio followed glacial and interglacial cycles and was consistent with the intensity of the East Asian monsoon and aridity of central Asia since 1.95 Ma. The changes of the ratio reflected three different stages of the East Asian monsoon and provenance climate.展开更多
By decomposing outgoing Iongwave radiation through empirical orthogonal function (EOF) analysis, the authors identify two anomalous convective systems in the tropical western Pacific. Besides the classical convectiv...By decomposing outgoing Iongwave radiation through empirical orthogonal function (EOF) analysis, the authors identify two anomalous convective systems in the tropical western Pacific. Besides the classical convective system near the Philippines (PC), there is another convective system near the Federated States of Micronesia (MC). As the first EOF component in this region, the variance explained by MC is higher than that by PC. Both MC and PC are regulated by the tropical sea surface temperature (SST) anomalies. While PC is associated with an El Ni^o event, MC is correlated with SST anomalies in the central and eastern Pacific during summer. It is also found that the East Asian summer monsoon (EASM) is influenced by these two convective systems. In general, enhanced (suppressed) convection corresponds to an eastwards (westwards) western Pacific subtropical high with weak (strong) intensity. Besides, the summer monsoon rainfall from the Yangtze River basin to Japan tends to increase (decrease) when PC is suppressed (enhanced). By comparison, the influence of MC is generally weak, with vague signals in the East Asian continent. Moreover, the influence of suppressed convection on the EASM is more significant than that of enhanced convection.展开更多
Responses of the Asian Summer Monsoon(ASM) in future projections have been studied based on two core future projections of phase five of the Coupled Model Intercomparison Project(CMIP5) coordinated experiments with th...Responses of the Asian Summer Monsoon(ASM) in future projections have been studied based on two core future projections of phase five of the Coupled Model Intercomparison Project(CMIP5) coordinated experiments with the IAP-coupled model FGOALS_s2(the Flexible Global Ocean-Atmosphere-Land System Model).The projected changes of the ASM in climatological mean and interannual variability were respectively reported.Both the South Asian Summer Monsoon(SASM) and the East Asian Summer Monsoon(EASM) were intensified in their climatology,featuring increased monsoon precipitation and an enhanced monsoon lower-level westerly jet flow.Accordingly,the amplitude of the annual cycle of rainfall over East Asia(EA) is enhanced,thereby indicating a more abrupt monsoon onset.After the EA monsoon onset,the EASM marched farther northward in the future scenarios than in the historical runs.In the interannual variability,the leading pattern of the EASM,defined by the first multi-variable EOF analysis over EA,explains more of the total variances in the warmest future scenario,specifically,Representative Concentration Pathway(RCP8.5).Also,the correlation coefficients analysis suggests that the relationship between the EASM interannual variations and ENSO was significantly strengthened in the future projections,which may indicate improved predictability of the EASM interannual variations.展开更多
The East Asian summer climate is modulated by a low-pressure system over northern East Asia(NEAL) and a subtropical high over the western North Pacific. Many studies have focused on the subtropical high, but little ...The East Asian summer climate is modulated by a low-pressure system over northern East Asia(NEAL) and a subtropical high over the western North Pacific. Many studies have focused on the subtropical high, but little is known about NEAL, especially its change in the future under global warming scenarios. This study investigates the projected change in NEAL in the late twenty-first century, using the outputs of 20 models from Phase 5 of the Coupled Model Intercomparison Project — specifically, their historical climate simulations(HIST) and future climate projections under the Representative Concentration Pathway 4.5(RCP4.5) and 8.5(RCP8.5) scenarios. The results show that the models capture the NEAL well in HIST. The NEAL is weakened in the late twenty-first century under the two RCP scenarios, with a stronger weakening under RCP8.5 than under RCP4.5.The weakened NEAL increases the geopotential height zonal gradient in the west and causes a southerly anomaly, which may bring more moisture and rainfall to northern East Asia.展开更多
HIV-1 evolves strongly and undergoes geographic differentiation as it spreads in diverse host populations around the world.For instance,distinct genomic backgrounds can be observed between the pandemic subtype B,preva...HIV-1 evolves strongly and undergoes geographic differentiation as it spreads in diverse host populations around the world.For instance,distinct genomic backgrounds can be observed between the pandemic subtype B,prevalent in Europe and North-America,and its offspring clade B' in East Asia.Here we ask whether this differentiation affects the selection pressure experienced by the virus.To answer this question we evaluate selection pressure on the HIV-1 envelope protein gp120 at the level of individual codons using a simple and fast estimation method based on the ratio ka/ks of amino acid changes to synonymous changes.To validate the approach we compare results to those from a state-of-the-art mixed-effect method.The agreement is acceptable,but the analysis also demonstrates some limitations of the simpler approach.Further,we find similar distributions of codons under stabilizing and directional selection pressure in gp120 for subtypes B and B' with more directional selection pressure in variable loops and more stabilizing selection in the constant regions.Focusing on codons with increased ka/ks values in B',we show that these codons are scattered over the whole of gp120,with remarkable clusters of higher density in regions flanking the variable loops.We identify a significant statistical association of glycosylation sites and codons with increased ka/ks values.展开更多
In this paper,the synoptic-climatology of Meiyn in East Asia is discussed.It is proposed that the location of the rain band of Meiyu is stable from the viewpoint of climatology,even though the active (wet) and break...In this paper,the synoptic-climatology of Meiyn in East Asia is discussed.It is proposed that the location of the rain band of Meiyu is stable from the viewpoint of climatology,even though the active (wet) and break (dry) Meiyu are influenced by synoptic systems.The duration and the onset and retreat dates of Meiyu exhibit tremendous interannual variabilities,and thus,they are almost unpredictable in seasonal climate prediction.The Meiyu has been used as a synoptic concept and applied to the operational forecast for many decades by meteorological agencies in East Asian countries.As a result,the prediction of the onset and retreat dates of Meiyu has become an important operational work for meteorological services.This has also misled the public's and scientists' attention.The northward propagation of the East Asian summer monsoon (EASM) surge associated with the intraseasonal oscillation is closely related to the active and break Meiyu.The activities and propagation of the EASM surge modulate the active/break Meiyu that cause concentrative severe precipitation processes and floods or droughts; hence,the authors suggest changing the current forecasting methodology of Meiyu.It is more meaningful from the scientific as well as application viewpoints to establish the monitoring and forecasting of the EASM surge to replace the current operational forecast of Meiyu after the seasonal progress enters the climatological Meiyu period in a year.展开更多
The genus Archimicrodon Hull,1945 is recorded for the first time from China.Two new species in the tribe Microdontini are described and illustrated:Archimicrodon(Hovamicrodon)huayangensis sp.nov.and Paramixogaster tri...The genus Archimicrodon Hull,1945 is recorded for the first time from China.Two new species in the tribe Microdontini are described and illustrated:Archimicrodon(Hovamicrodon)huayangensis sp.nov.and Paramixogaster trifasciatus sp.nov.An updated key to the genus Paramixogaster from China is provided.展开更多
A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (P1) emis...A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (P1) emissions over East Asia to examine the aerosol indirect effect on clouds. As a result of an increase in aerosols in January, the cloud droplet number increased by 650 cm-3 over the ocean and East China, 400 cm-3 over Central and Southwest China, and less than 200 cm-3 over North China. The cloud liquid water path (LWP) increased by 40-60 g m-2 over the ocean and Southeast China and 30 g m-2 over Central China; the LWP in- creased less than 5 g m-2 or decreased by 5 g m2 over North China. The effective radius (Re) decreased by more than 4 pm over Southwest, Central, and Southeast China and 2 pm over North China. In July, variations in cloud properties were more uniform; the cloud droplet number increased by approximately 250400 cm-3, the LWP increased by approximately 30-50 g m 2, and Re decreased by approximately 3 μm over most regions of China. In response to cloud property changes from PI to PD, shortwave (SW) cloud radiative m-2 over the ocean and 10 forcing strengthened by 30 W W m-2 over Southeast China, and it weakened slightly by approximately 2-10 W m-2 over Central and Southwest China in January. In July, SW cloud radiative forcing strengthened by 15 W m-2 over Southeast and North China and weakened by l0 W m-2 over Central China. The different responses of SW cloud radiative forcing in different regions was related to cloud feedbacks and natural variability.展开更多
A synoptic snapshot in this study is made for the East Cape Eddy (ECE) basedon the World Ocean Circulation Experiment (WOCE) P14C Hydrographic Section and Shipboard ADCPvelocity vector data collected in September 1992...A synoptic snapshot in this study is made for the East Cape Eddy (ECE) basedon the World Ocean Circulation Experiment (WOCE) P14C Hydrographic Section and Shipboard ADCPvelocity vector data collected in September 1992. The ECE is an anticyclonic eddy, barotropicallystructured and centered at 33.64°S and 176.21°E, with warm and salinous-cored subsurface water.The radius of the eddy is of the order O (110 km) and the maximum circumferential velocity is O (40cm s^(-1)); as a result, the relative vorticity is estimated to be O (7 x 10^(-6)s^(-1)). Due to theexistence of the ECE, the mixed layer north of New Zealand becomes deeper, reaching a depth of 300m in the austral winter. The ECE plays an important role in the formation and distribution of theSubtropical Mode Water (STMW) over a considerable area in the South Pacific.展开更多
The distinct influences of eastern Pacific (EP) and central Pacific (CP) La Nina on rainfall anomalies over Southeast Asia and Australia in boreal autumn (September to November) are explored in this study. Compo...The distinct influences of eastern Pacific (EP) and central Pacific (CP) La Nina on rainfall anomalies over Southeast Asia and Australia in boreal autumn (September to November) are explored in this study. Composite results reveal that CP La Nina gives rise to significant and severe flooding over Southeast Asia and Australia, whereas EP La Nina fails to exert any evident impacts on rainfall over this region. This difference can be attributed to the distinct features of cooling sea surface temperature anomalies (SSTAs) between EP and CP La Nina. With a more westward location and stronger intensity of the negative SSTAs during CP La Nina autumn, the highest and lowest SLP anomalies are substantially enhanced and shift westwards too, further causing intense easterly winds over the western Pacific and westerly anomalies over the Indian Ocean driven by this SLP gradient. Subsequently, robust low-level convergence and high-level divergence is observed over the Maritime Continent and Australia, resulting in significant above-normal rainfall anomalies in those regions. In contrast, weak and eastern Pacific-confined cooling SSTAs during EP La Nina produce correspondingly weak low-level convergence over the Maritime Continent conditions that make it hard for significant rainfall anomalies to arise.展开更多
Indonesia, as the largest archipelagic state in the world, shares maritimeborders with many countries including Malaysia in the Straits of Malacca, the South China Sea and the Celebes Sea. Because of its geopolitical ...Indonesia, as the largest archipelagic state in the world, shares maritimeborders with many countries including Malaysia in the Straits of Malacca, the South China Sea and the Celebes Sea. Because of its geopolitical location these borders are very porous and, as a consequence, are highly difficult to monitor and control, making it vulnerable spots for illegal activities such as arms smuggling. This paper aims to examine the challenges faced by Indonesia and Malaysia in dealing with the main security border issues. The paper then concludes that Malaysia has become the main route for small arms illicit trafficking from other Southeast Asian countries to Indonesia's conflict areas. Indonesia and Malaysia face an enormous challenge, particularly in view of the recent happenings in conflict zones and the increasingly need to secure their common borders.展开更多
The beginning of the XXI century was marked a new rising of the international tectonic cartography as a result of analysis and synthesis of a huge volume of geological information obtained for the territory of Asia e...The beginning of the XXI century was marked a new rising of the international tectonic cartography as a result of analysis and synthesis of a huge volume of geological information obtained for the territory of Asia es-pecially during the last 30 years. The previous tectonic maps for Asia were created in the 1960s-1970s of the last century. Since that time, the national geological surveys have compiled tectonic maps exclusively in the limits of their own state boundaries. The international cooperation of five countries since 2002 ( Russia, China, Mongolia, Kazakhstan and Republic of Korea) gave a unique possibility to join the data into a united cartog-raphic form as Atlas of Geological Maps (since 2002-Atlas of Geological Maps of Central Asia and since 2007- Atlas of Geological Maps of Northem-Central-Eastem Asia). Both atlases include four maps: geological, tecton-ic ,metallogenic, and energy resources. Tectonic Map of Northem-Central-Eastem Asia and Adjacent Areas at scale 1 : 2 500 000 was the key map for further compilation of the metallogenic and energy resources ( coal, oil and gas) maps. By this reason, special attention was given to showing the structure and composition of the Mes-ozoic sedimentary basins in Northern-Central- Eastern Asia as the most perspective structures for oil-and-gas and coal prospect.展开更多
基金supported by the National Basic Research Program of China(Grant No.2013CB430201)the China Meteorological Administration Special Fund for Scientific Research in the Public Interest(Grant No.GYHY201206008)
文摘The characteristics of the summer precipitation diurnal cycle over South Asia and East Asia during 2001–13 are investigated based on the high spatiotemporal resolution estimates of the CPC(Climate Prediction Center) Morphing(CMORPH) technique. The results show that summer precipitation over South Asia and East Asia possesses a remarkable diurnal cycle, with obvious regional differences. Over the coastal areas, plateau, and high mountains, summer precipitation peaks in the late afternoon; while over low altitude areas, such as valleys, basins, and inshore seas, it peaks during midnight to early morning. In addition to these general features consistent with previous studies, the high resolution CMORPH technique can depict finer regional details, such as the less coherent phase pattern over a few regions. Besides, through comparative analysis of the diurnal cycle strength and precipitation fields, the authors find that for humid areas the summer precipitation diurnal cycle is especially significant over Southeast China, the Sichuan Basin, Hainan Province, Taiwan Province, the Philippines, and Indonesia. And it is relatively weak over the south of Northeast China, central East China, Yunnan Province, the central Indian Peninsula, and most oceanic areas. Comparisons between two satellite datasets—those of the CMORPH and Tropical Rainfall Measuring Mission(TRMM) 3B42 products—are also presented. For summer precipitation and the main diurnal cycle features, the results from both products agree over most regions, except a few areas, e.g., the Tibetan Plateau.
基金supported by the National Natural Science Foundation of China[grant number 41320104007]
文摘It is well known that precipitation anomalies in the tropical western North Pacific (WNP) significantly affect circulation and rainfall in East Asia during summer. In this study, the authors further investigated this relationship, by examining the anomalies associated with positive and negative precipitation anomalies in the tropical WNP. The results suggest these anomalies are asymmetric between the enhanced and suppressed WNP rainfall. Positive precipitation anomalies over the WNP, in comparison with their negative counterparts, are more closely related to the meridional teleconnection pattern and rainfall anomalies along the East Asian rain belt. The implications of the results are discussed.
基金supported by the National Basic Research Program of China(2009CB421406)the Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX2-YW-Q1-02)the National Natural Science Foundation of China(4090205 and 40975050)
文摘In this study, the authors simulate the East Asian climate changes in the mid-Pliocene (~3.3 to 3.0 Ma BP) with the Community Atmosphere Model version 3.1 (CAM3.1) and compare the simulated East Asian monsoon with paleoclimate data. The simulations show an obvious warming pattern in East Asia in the mid-Pliocene compared with the pre-industrial climate, with surface air temperature increasing by 0.5 4.0°C. In the warm mid-Pliocene simulation, the East Asian Summer Monsoon (EASM) becomes stronger, while the East Asian Winter Monsoon (EAWM) is similar relative to the pre-industrial climate. Compared with the paleoclimate data, our simulations depict the intensified EASM well but cannot reproduce the weakened EAWM. This model-data discrepancy may be attributed to the uncertainty in the reconstructed mid-Pliocene sea surface temperature.
基金Joint Project of Natural Science Foundation of China and Yunnan Province (U0833602)
文摘The first two series(RMM1 and RMM2) of RMM Index(all-Season Real-time Multivariate MJO Index) are computed to obtain the interannual variation of the preceding winter(preceding December to current February) MJO strength,according to which active(or inactive) years of preceding winter MJO are divided.By utilizing the data provided by NCEP/NCAR,CMAP and China's 160 stations from 1979 to 2008,we studied the preceding winter MJO strength and discovered that the summer precipitation in the basin are of significantly negative correlation,i.e.when the preceding winter MJO is relatively active,the summer precipitation in the basin decreases,and vise verse.We also analyzed the causes.When the preceding winter MJO is relatively active,its release of potential heat facilities Inter-Tropical Convergence Zone(ITCZ) to strengthen and locate northward in winter and propagate northeastward.This abnormal situation lasts from winter to summer.In mid-May,ITCZ jumps northward to the South China Sea,the western Pacific subtropical high withdraws eastward,and the South China Sea summer monsoon sets off and strengthens.In summer,ITCZ propagates to South China Sea-subtropical western Pacific,the zonal circulation of subtropical Pacific strengthens,and a local meridional circulation of the South China Sea to the basin area forms,giving rise to the East Asia Pacific teleconnection wave-train.An East Asian monsoon trough and the Meiyu front show opposite features from south to north,the East Asian summer monsoon strengthens and advances northward.As a result,the summer monsoon is weakened as the basin is controlled by the subtropical high continually,with less rain in summer.On the contrary,when the preceding winter MJO is inactive,ITCZ weakens and is located southward,the subtropical high is located southward in summer,and the basin is in a region of ascending airflow with prevailing southwest wind.The East Asian monsoon trough and EASM weaken so that summer monsoon is reduced in the basin where precipitation increases.
基金supported by the National Key R&D Program of China grant number 2017YFA0603802the Strategic Priority Research Program of the Chinese Academy of Sciences grant number XDA2006040102National Natural Science Foundation of China grant number 41675084。
文摘The East Asian westerly jet(EAJ)plays a crucial role in affecting the East Asian summer rainfall(EASR).Therefore,evaluations of EAJ simulations are vital for improving the understanding and projections of climate change in East Asia.This study evaluates the simulations of the climatology and interannual variability in the present-day summer EAJ in the CMIP6 models and compares the results with those in the CMIP5 models by analyzing the historical climate simulations of 29 CMIP5 models and 21 CMIP6 models during the period from 1986–2005.In general,the CMIP6 models capture the EAJ more realistically than the CMIP5 models.The results show that the CMIP6 models reasonably capture the spatial features of the climatological zonal wind at 200 hPa and simulate a smaller zonal wind bias along the EAJ.The locations of the EAJ’s core are at the observed location in nearly all CMIP6 models but in only approximately two-thirds of the CMIP5 models.The EAJ’s intensity is closer to the observed value and exhibits a smaller intermodel dispersion in the CMIP6 models.The CMIP6 models also show an improved ability to reproduce the interannual variability in the EAJ’s meridional displacement and have a stronger relationship with the EASR.
基金supported by the National Natural Science Foundation of China[grant numbers 41375086 and 41775062]the National Natural Science Foundation of China[grant number 41630530]+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(CAS)supported by the Youth Innovation Promotion Association of CAS
文摘This study reveals a significant relationship, on the interannual timescale, between a dipole mode, the second leading mode, of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asia. Related to the dipole mode, with the heavier sea ice in the north and lighter sea ice in the southeast Barents Sea in spring, the East Asian summer subtropical rainy belt tends to move northward. The significant relationship is established through a wave train over northern Eurasia in the lower troposphere in June. The wave train enhances the northern East Asian low, which induces more rainfall to the north of the East Asian subtropical rainy belt and then attracts the subtropical rainy belt to move northward. This study suggests that the dipole mode of spring sea-ice anomalies in the Barents Sea may be a good precursor for the prediction of East Asian summer rainfall.
基金Supported by the National Basic Research Program of China(973 Program)(No.2007CB411703)the National Natural Science Foundation of China(No.40976026)
文摘To understand the provenance and evolution of eolian input in the last 1.95 Ma in the Parece Vela Basin in the eastern Philippine Sea, the clay mineral assemblage of a gravity core PV090510 from the basin was investigated using paleogeomagnetic dating and X-ray diffraction. The assemblage of the core mainly consisted of smectite (-46%) and illite (-40%), with some chlorite (-10%) and kaolinite (-4%). Analysis of the provenance of these minerals suggested that smectite was mainly derived from volcanic rocks of the Mariana Arc, while illite, chlorite, and kaolinite were mainly transported as eolian dust by the East Asian monsoon from central Asia. We used the ratio of (illite+chlorite+kaolinite)/smectite as a proxy for Asian eolian input to the Parece Vela Basin since 1.95 Ma. This ratio followed glacial and interglacial cycles and was consistent with the intensity of the East Asian monsoon and aridity of central Asia since 1.95 Ma. The changes of the ratio reflected three different stages of the East Asian monsoon and provenance climate.
基金supported by the National Natural Science Foundation of China[grant number 41475052]
文摘By decomposing outgoing Iongwave radiation through empirical orthogonal function (EOF) analysis, the authors identify two anomalous convective systems in the tropical western Pacific. Besides the classical convective system near the Philippines (PC), there is another convective system near the Federated States of Micronesia (MC). As the first EOF component in this region, the variance explained by MC is higher than that by PC. Both MC and PC are regulated by the tropical sea surface temperature (SST) anomalies. While PC is associated with an El Ni^o event, MC is correlated with SST anomalies in the central and eastern Pacific during summer. It is also found that the East Asian summer monsoon (EASM) is influenced by these two convective systems. In general, enhanced (suppressed) convection corresponds to an eastwards (westwards) western Pacific subtropical high with weak (strong) intensity. Besides, the summer monsoon rainfall from the Yangtze River basin to Japan tends to increase (decrease) when PC is suppressed (enhanced). By comparison, the influence of MC is generally weak, with vague signals in the East Asian continent. Moreover, the influence of suppressed convection on the EASM is more significant than that of enhanced convection.
基金supported by the Chinese Acad-emy of Sciences (XDA05110303)the National Basic Research Program of China (973 Program,2012CB417203)the National Natural Science Foundation of China (40805038 and 41023002)
文摘Responses of the Asian Summer Monsoon(ASM) in future projections have been studied based on two core future projections of phase five of the Coupled Model Intercomparison Project(CMIP5) coordinated experiments with the IAP-coupled model FGOALS_s2(the Flexible Global Ocean-Atmosphere-Land System Model).The projected changes of the ASM in climatological mean and interannual variability were respectively reported.Both the South Asian Summer Monsoon(SASM) and the East Asian Summer Monsoon(EASM) were intensified in their climatology,featuring increased monsoon precipitation and an enhanced monsoon lower-level westerly jet flow.Accordingly,the amplitude of the annual cycle of rainfall over East Asia(EA) is enhanced,thereby indicating a more abrupt monsoon onset.After the EA monsoon onset,the EASM marched farther northward in the future scenarios than in the historical runs.In the interannual variability,the leading pattern of the EASM,defined by the first multi-variable EOF analysis over EA,explains more of the total variances in the warmest future scenario,specifically,Representative Concentration Pathway(RCP8.5).Also,the correlation coefficients analysis suggests that the relationship between the EASM interannual variations and ENSO was significantly strengthened in the future projections,which may indicate improved predictability of the EASM interannual variations.
基金supported by the National Natural Science Foundation of China[grant number 41375086],[grant number41305063]
文摘The East Asian summer climate is modulated by a low-pressure system over northern East Asia(NEAL) and a subtropical high over the western North Pacific. Many studies have focused on the subtropical high, but little is known about NEAL, especially its change in the future under global warming scenarios. This study investigates the projected change in NEAL in the late twenty-first century, using the outputs of 20 models from Phase 5 of the Coupled Model Intercomparison Project — specifically, their historical climate simulations(HIST) and future climate projections under the Representative Concentration Pathway 4.5(RCP4.5) and 8.5(RCP8.5) scenarios. The results show that the models capture the NEAL well in HIST. The NEAL is weakened in the late twenty-first century under the two RCP scenarios, with a stronger weakening under RCP8.5 than under RCP4.5.The weakened NEAL increases the geopotential height zonal gradient in the west and causes a southerly anomaly, which may bring more moisture and rainfall to northern East Asia.
基金Deutsche Forschungsgemeinschaft(http://www.dfg.de),grant TRR60/A6the University of Duisburg-Essen(http://www.uni-due.de)the Chinese Key National Science and Technology Program in the 12th Five-YearPeriod,grant 2012ZX10001006-002
文摘HIV-1 evolves strongly and undergoes geographic differentiation as it spreads in diverse host populations around the world.For instance,distinct genomic backgrounds can be observed between the pandemic subtype B,prevalent in Europe and North-America,and its offspring clade B' in East Asia.Here we ask whether this differentiation affects the selection pressure experienced by the virus.To answer this question we evaluate selection pressure on the HIV-1 envelope protein gp120 at the level of individual codons using a simple and fast estimation method based on the ratio ka/ks of amino acid changes to synonymous changes.To validate the approach we compare results to those from a state-of-the-art mixed-effect method.The agreement is acceptable,but the analysis also demonstrates some limitations of the simpler approach.Further,we find similar distributions of codons under stabilizing and directional selection pressure in gp120 for subtypes B and B' with more directional selection pressure in variable loops and more stabilizing selection in the constant regions.Focusing on codons with increased ka/ks values in B',we show that these codons are scattered over the whole of gp120,with remarkable clusters of higher density in regions flanking the variable loops.We identify a significant statistical association of glycosylation sites and codons with increased ka/ks values.
基金supported by the National Basic Research Program of China(2012CB417205)Open Fund of State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences(2012LASW-A02)Basic Research Fund of Chinese Academy of Meteorological Sciences(2010Z001)
文摘In this paper,the synoptic-climatology of Meiyn in East Asia is discussed.It is proposed that the location of the rain band of Meiyu is stable from the viewpoint of climatology,even though the active (wet) and break (dry) Meiyu are influenced by synoptic systems.The duration and the onset and retreat dates of Meiyu exhibit tremendous interannual variabilities,and thus,they are almost unpredictable in seasonal climate prediction.The Meiyu has been used as a synoptic concept and applied to the operational forecast for many decades by meteorological agencies in East Asian countries.As a result,the prediction of the onset and retreat dates of Meiyu has become an important operational work for meteorological services.This has also misled the public's and scientists' attention.The northward propagation of the East Asian summer monsoon (EASM) surge associated with the intraseasonal oscillation is closely related to the active and break Meiyu.The activities and propagation of the EASM surge modulate the active/break Meiyu that cause concentrative severe precipitation processes and floods or droughts; hence,the authors suggest changing the current forecasting methodology of Meiyu.It is more meaningful from the scientific as well as application viewpoints to establish the monitoring and forecasting of the EASM surge to replace the current operational forecast of Meiyu after the seasonal progress enters the climatological Meiyu period in a year.
基金supported by the National Natural Science Foundation of China(31900345)the Natural Science Basic Research Plans in Shaanxi Province of China(2021JQ-757,2019JZ-34)+2 种基金the Scientific Research Program Funded by Shaanxi Provincial Education Department(21JK0555)the Foundation of Shaanxi University of Technology(SLGRC13)the Opening Foundation of Shaanxi University of Technology(SLGPT2019KF02-02)。
文摘The genus Archimicrodon Hull,1945 is recorded for the first time from China.Two new species in the tribe Microdontini are described and illustrated:Archimicrodon(Hovamicrodon)huayangensis sp.nov.and Paramixogaster trifasciatus sp.nov.An updated key to the genus Paramixogaster from China is provided.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q11-04)the "Strategic Priority Research Program" of the Chinese Academy of Sciences (XDA05100502)
文摘A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (P1) emissions over East Asia to examine the aerosol indirect effect on clouds. As a result of an increase in aerosols in January, the cloud droplet number increased by 650 cm-3 over the ocean and East China, 400 cm-3 over Central and Southwest China, and less than 200 cm-3 over North China. The cloud liquid water path (LWP) increased by 40-60 g m-2 over the ocean and Southeast China and 30 g m-2 over Central China; the LWP in- creased less than 5 g m-2 or decreased by 5 g m2 over North China. The effective radius (Re) decreased by more than 4 pm over Southwest, Central, and Southeast China and 2 pm over North China. In July, variations in cloud properties were more uniform; the cloud droplet number increased by approximately 250400 cm-3, the LWP increased by approximately 30-50 g m 2, and Re decreased by approximately 3 μm over most regions of China. In response to cloud property changes from PI to PD, shortwave (SW) cloud radiative m-2 over the ocean and 10 forcing strengthened by 30 W W m-2 over Southeast China, and it weakened slightly by approximately 2-10 W m-2 over Central and Southwest China in January. In July, SW cloud radiative forcing strengthened by 15 W m-2 over Southeast and North China and weakened by l0 W m-2 over Central China. The different responses of SW cloud radiative forcing in different regions was related to cloud feedbacks and natural variability.
文摘A synoptic snapshot in this study is made for the East Cape Eddy (ECE) basedon the World Ocean Circulation Experiment (WOCE) P14C Hydrographic Section and Shipboard ADCPvelocity vector data collected in September 1992. The ECE is an anticyclonic eddy, barotropicallystructured and centered at 33.64°S and 176.21°E, with warm and salinous-cored subsurface water.The radius of the eddy is of the order O (110 km) and the maximum circumferential velocity is O (40cm s^(-1)); as a result, the relative vorticity is estimated to be O (7 x 10^(-6)s^(-1)). Due to theexistence of the ECE, the mixed layer north of New Zealand becomes deeper, reaching a depth of 300m in the austral winter. The ECE plays an important role in the formation and distribution of theSubtropical Mode Water (STMW) over a considerable area in the South Pacific.
基金supported by the National Natural Science Foundation of China[grant number 41230527][grant number41675091][grant number 41461164005]
文摘The distinct influences of eastern Pacific (EP) and central Pacific (CP) La Nina on rainfall anomalies over Southeast Asia and Australia in boreal autumn (September to November) are explored in this study. Composite results reveal that CP La Nina gives rise to significant and severe flooding over Southeast Asia and Australia, whereas EP La Nina fails to exert any evident impacts on rainfall over this region. This difference can be attributed to the distinct features of cooling sea surface temperature anomalies (SSTAs) between EP and CP La Nina. With a more westward location and stronger intensity of the negative SSTAs during CP La Nina autumn, the highest and lowest SLP anomalies are substantially enhanced and shift westwards too, further causing intense easterly winds over the western Pacific and westerly anomalies over the Indian Ocean driven by this SLP gradient. Subsequently, robust low-level convergence and high-level divergence is observed over the Maritime Continent and Australia, resulting in significant above-normal rainfall anomalies in those regions. In contrast, weak and eastern Pacific-confined cooling SSTAs during EP La Nina produce correspondingly weak low-level convergence over the Maritime Continent conditions that make it hard for significant rainfall anomalies to arise.
文摘Indonesia, as the largest archipelagic state in the world, shares maritimeborders with many countries including Malaysia in the Straits of Malacca, the South China Sea and the Celebes Sea. Because of its geopolitical location these borders are very porous and, as a consequence, are highly difficult to monitor and control, making it vulnerable spots for illegal activities such as arms smuggling. This paper aims to examine the challenges faced by Indonesia and Malaysia in dealing with the main security border issues. The paper then concludes that Malaysia has become the main route for small arms illicit trafficking from other Southeast Asian countries to Indonesia's conflict areas. Indonesia and Malaysia face an enormous challenge, particularly in view of the recent happenings in conflict zones and the increasingly need to secure their common borders.
基金the project of the Federal Agency for Scientific Organizations of the Ministry of Education and Science of the Russian Federation ( Registration Number 0135 -2014 -0065 )the support of the Russian Science Foundation ( Grant 16 -17 -10251 )
文摘The beginning of the XXI century was marked a new rising of the international tectonic cartography as a result of analysis and synthesis of a huge volume of geological information obtained for the territory of Asia es-pecially during the last 30 years. The previous tectonic maps for Asia were created in the 1960s-1970s of the last century. Since that time, the national geological surveys have compiled tectonic maps exclusively in the limits of their own state boundaries. The international cooperation of five countries since 2002 ( Russia, China, Mongolia, Kazakhstan and Republic of Korea) gave a unique possibility to join the data into a united cartog-raphic form as Atlas of Geological Maps (since 2002-Atlas of Geological Maps of Central Asia and since 2007- Atlas of Geological Maps of Northem-Central-Eastem Asia). Both atlases include four maps: geological, tecton-ic ,metallogenic, and energy resources. Tectonic Map of Northem-Central-Eastem Asia and Adjacent Areas at scale 1 : 2 500 000 was the key map for further compilation of the metallogenic and energy resources ( coal, oil and gas) maps. By this reason, special attention was given to showing the structure and composition of the Mes-ozoic sedimentary basins in Northern-Central- Eastern Asia as the most perspective structures for oil-and-gas and coal prospect.