Is the westerly rotation of the lithosphere an ephemeral accidental recent phenomenon or is it a stable process of Earth's geodynamics? The reason why the tidal drag has been questioned as the mechanism determinin...Is the westerly rotation of the lithosphere an ephemeral accidental recent phenomenon or is it a stable process of Earth's geodynamics? The reason why the tidal drag has been questioned as the mechanism determining the lithospheric shift relative to the underlying mantle is the apparent too high viscosity of the asthenosphere. However, plate boundaries asymmetries are a robust indication of the 'westerly'decoupling of the entire Earth's outer lithospheric shell and new studies support lower viscosities in the low-velocity layer(LVZ) atop the asthenosphere. Since the solid Earth tide oscillation is longer in one side relative to the other due to the contemporaneous Moon's revolution, we demonstrate that a non-linear rheological behavior is expected in the lithosphere mantle interplay. This may provide a sort of ratchet favoring lowering of the LVZ viscosity under shear, allowing decoupling in the LVZ and triggering the westerly motion of the lithosphere relative to the mantle.展开更多
The possibility of a net rotation of the lithosphere with respect to the mantle is generally overlooked since it depends on the adopted mantle reference frames, which are arbitrary. We review the geological and geophy...The possibility of a net rotation of the lithosphere with respect to the mantle is generally overlooked since it depends on the adopted mantle reference frames, which are arbitrary. We review the geological and geophysical signatures of plate boundaries, and show that they are markedly asymmetric worldwide. Then we compare available reference frames of plate motions relative to the mantle and discuss which is at best able to fit global tectonic data. Different assumptions about the depths of hotspot sources （below or within the asthenosphere, which decouples the lithosphere from the deep mantle） predict different rates of net rotation of the lithosphere relative to the mantle. The widely used no-net-rotation （NNR） reference frame, and low （〈0.2°-0.4°/Ma） net rotation rates （deep hotspots source） predict an average net rotation in which some plates move eastward relative to the mantle （e.g., Nazca）. With fast （〉1°/Ma） net rotation （shallow hotspots source）, all plates, albeit at different velocity, move westerly along a curved trajectory, with a tectonic equator tilted about 30° relative to the geographic equator. This is consistent with the observed global tectonic asymmetries.展开更多
Some Western scholars have re-examined the concept of“Chinese medicine”and its knowledge system under the influence of global history research methods in recent years,in an attempt to understand the factors that led...Some Western scholars have re-examined the concept of“Chinese medicine”and its knowledge system under the influence of global history research methods in recent years,in an attempt to understand the factors that led to the spread of Chinese medicine around the world,and what kind of Chinese medicine is constituted outside of China.Thus,researchers have studied the initial stage of traditional Chinese medicine(TCM)’s entry into the western world,tracing its roots and observing new knowledge systems formed in the process of cross-cultural communication.Responding to the research of Western scholars,this paper studies the Radicis Chynae(《中国根书简》Letters on Chinese Root),a monograph written by Andreas Vesalius,a famous European anatomist who lived in the 16th century.The author of this article examined the understanding and interpretation of Chinese medicine by the European intelligentsia from 16th to 19th century,investigated the influence of the westward spread of TCM on the scientific revolution and medical progress in Europe,and analyzed its relationship with the rise of Sinology in Europe.This article discusses the knowledge interaction between Chinese medicine and the formation of modern European medicine from the perspective of global history and cross-culture.展开更多
Using data available from the Retrieval System Based on Yearbooks of Tropical Cyclones over the Western North Pacific,NCEP/NCAR reanalysis daily data and observed precipitation data for 1959 to 2007 in Yunnan,a provin...Using data available from the Retrieval System Based on Yearbooks of Tropical Cyclones over the Western North Pacific,NCEP/NCAR reanalysis daily data and observed precipitation data for 1959 to 2007 in Yunnan,a province located in a low-latitude plateau,this work analyzes the climatic characteristics and the corresponding large-scale circulation patterns related to the western North Pacific westward moving TCs(WMTCs).Its impacts on the rainfall in the Yunnan Plateau are studied.Results show that WMTCs happen almost every year,mainly from July to September.It shows a downward trend in decadal variation.Nearly the entire Yunnan area is affected by them but the eastern part experiences the most severe influences.Most of the WMTCs migrate from the South China Sea,primarily make landfall in Hainan and Guangdong and enter the Northern Bay.The tracks of these typhoons can be classified into five categories,in which the most significant impact results from those making landfall in Guangdong.All categories of the tropical cyclones can induce province-wide heavy rainfall in Yunnan.Super typhoons bring about the heaviest and most extensive rainfall over the low-latitude plateau while the associated circulation pattern is marked with a dominant 500 hPa meridional circulation at middle latitudes,an active monsoon depression and Intertropical Convection Zone(ITCZ) at low latitudes and a westward-located South Asia High at 100 hPa,which is favorable for tropical cyclones to travel westward.WMTCs tend to go westward into the interior part of China if the subtropical high extends its westernmost ridge point to the northeast of Yunnan,or expands its periphery anti-cyclonic circulation to the Tibetan Plateau,or merges with the Qinghai-Tibetan high.展开更多
The westward migration of tropical cyclone(TC)activity has been identified in the western North Pacific(WNP),but the related features and causes remain elusive.Here,based on the best track data from China,Japan,and th...The westward migration of tropical cyclone(TC)activity has been identified in the western North Pacific(WNP),but the related features and causes remain elusive.Here,based on the best track data from China,Japan,and the US,and the NCEP–NCAR reanalysis data in 1982–2020,we investigate characteristics of the westward migration of the WNP TC activity with various metrics,and reveal possible causes for the migration of TC tracks through analyzing its seasonality and dependence on environmental conditions.The results show that the WNP TCs show significant westward migrations in a number of metrics,including location of tracks,genesis,the first track point at which TC reaches its lifetime-maximum intensity,and the last track point in the TC lifetime.It is found that TC tracks exhibit more significant westward migrations in the easterly steering flow than in the westerly steering flow.Meanwhile,the TC longitude shift shows notable seasonal variations,for which the TCs in the easterlies move further west than those in the westerlies during July–September,vice versa during October–December.The dependence of the westward migration of TC tracks on background steering flow is associated with the different environmental conditions.The westward shift in the westerly steering is mainly due to the reduced vertical wind shear(VWS),while the weakened zonal easterly steering and reduced VWS are both closely related to the westward migration in the easterly steering.These results have important implications for understanding current and future variations in TC longitude shift.展开更多
The nationalization,modernization,and Chinafication of artistic creation are the motivation for pushing forward the further development of art and advocating Chinese culture.During the Comprehensive War of resistance ...The nationalization,modernization,and Chinafication of artistic creation are the motivation for pushing forward the further development of art and advocating Chinese culture.During the Comprehensive War of resistance Against Japanese Aggression,the painter Wu Zuoren answered the art community's call of the times and went twice westward to Xizang for sketching;these trips enriched his artistic creation with Tibetan culture and inspired him to some national paintings;he not only changed and diversified his painting style,but also held a series of exhibitions and communication events,which deepened the understanding and love for Tibetan culture among people from home and abroad.Many of his Tibetan paintings,as they spread across China,have gradually become symbols of Chinese culture shared by multiple ethnic groups;these Tibetan paintings not only demonstrate the united image and general status of the Chinese nation but also serve as vivid cases for the study of forging a strong sense of community for the Chinese nation.展开更多
It has historically been very difficult to trace the history of the westward transmission of Chinese medicine through the accounts of its protagonists. Many of the early scholars such as Jack Worsley, Dick Van Buren, ...It has historically been very difficult to trace the history of the westward transmission of Chinese medicine through the accounts of its protagonists. Many of the early scholars such as Jack Worsley, Dick Van Buren, and Joe Goodman were reluctant to divulge information about the source of their knowledge, or their professional qualifications. Others, such as John Shen and Hong Yuan-bain were early 20th century immigrants who transmitted highly personalized versions of acupuncture and Chinese medicine to select disciples. Eventually, a new class of scholars appeared, including names such as Ted Kaptchuk, Peter Deadman, Nigel Wiseman, William Morris, Peter Eckman, John Mc Donald, Charles Buck, and the late Giovanni Maciocia who looked for answers back in China, developed translation methodologies and terminology, compiled the main textbooks currently in use at TCM colleges, overcame enormous scholastic adversity, developed courses and pursued the regulation and accreditation of TCM in various countries. This special issue synopsizes the path towards the global acculturation of TCM over the last 50 years, the main protagonists, the enormous accomplishments they have achieved for the profession, their philosophy, their clinical perspectives and visions for the future.展开更多
The main geomagnetic field models of IGRF1900-2000 are used to study the latitude-dependence of the westward drift in the main field. The results show that the latitude-dependence exists in the magnetic components wit...The main geomagnetic field models of IGRF1900-2000 are used to study the latitude-dependence of the westward drift in the main field. The results show that the latitude-dependence exists in the magnetic components with different wavelengths (m=1-10). The global-average westward drift rate of the component of m=1 is 0.189°/a with the maximum of 0.295°/a at latitudes 40°-45°. The compo-nent of m=2 has an average drift rate of 0.411°/a with the maximum of 1.305°/a at latitude -60°. As for the compo-nents with further shorter wavelengths, the drift is generally restricted in a limited latitude range, and has many smaller drift rates. This latitude-dependence of westward drift can not be explained by rigid rotation of the earth’s core. The results of this note also show that there is a negative disper-sion in the westward drift, namely the components of long wavelengths drift faster than those of short wavelengths. This dispersion feature is not in agreement with Hide’s MHD model. It is likely needed展开更多
Taking the advantage of sun glitter(SG)observed from high-resolution satellites Gaofen-1(GF-1)and Gaofen-6(GF-6),a new method named Shield and Vortex 1-2(SAV1-2)for extracting spatial texture information from sun glit...Taking the advantage of sun glitter(SG)observed from high-resolution satellites Gaofen-1(GF-1)and Gaofen-6(GF-6),a new method named Shield and Vortex 1-2(SAV1-2)for extracting spatial texture information from sun glitter was established.Sea surface texture detail information around Diaoyu Dao and its affiliated islands was extracted using SAV1-2.Meanwhile,the dynamic characteristics of the water environment were analyzed by combining the water color,temperature and dynamic data.The results show the following information.(1)Stable westward shield effect and eastward Karman vortex streets,extracted from SG,appear upstream(westward)and downstream(eastward)of the Diaoyu Dao and its affiliated islands respectively.(2)The dominant direction of the Kuroshio Current in the Diaoyu Dao and its affiliated islands area is east,the Diaoyu Dao and its affiliated islands interacting with Kuroshio,inducing western shield and eastern shelter and wake.Furthermore,wave intervals of the shield in front of the island range from hundreds to thousands of metres,and extend wider than the island itself.(3)Combining with high-resolution sea surface temperature(SST)and chlorophyll a(Chl a)concentration,the directional changes of water color elements are mutually supported and proved with the stable shield(wave packet)effect in the west and vortex street effect in the east.The change of SST upstream of the island(western shield area)is not significant,the temperature in the downstream shelter area decreases slightly,and the SST in the downstream wake area shows a general trend of obvious decrease.The wake area is dominated by Karman vortex streets in shape,supplementing by vortices.The concentration of Chl a in the west shield of island is as low as that in downstream shelter area,while it increases significantly in the downstream wake area with shape in eddy or ribbon.(4)The SAV methods of extracting sea surface texture detail using SG can be widely used in different sea areas and water quality.This paper can provide reference for the protection and development of Diaoyu Dao and its affiliated islands and its surrounding waters.It is suggested that some kind of current buffer,such as marine wind farm,should be established in the western waters of Diaoyu Dao and its affiliated islands to protect the islands,and marine pasture should be developed in the downstream of eastern waters of Diaoyu Dao and its affiliated islands.展开更多
During June-July 2020,the strongest recorded mei-yu rainfall occurred in the middle and lower reaches of the Yangtze River.The rainfall processes exhibited an obvious quasi-biweekly(biweekly in brief)variability,and t...During June-July 2020,the strongest recorded mei-yu rainfall occurred in the middle and lower reaches of the Yangtze River.The rainfall processes exhibited an obvious quasi-biweekly(biweekly in brief)variability,and there are altogether five cycles.It is found that the biweekly rainfall cycle mainly arises from the collaborative effects of biweekly variabilities from both the tropics and extratropics.As for the tropics,the biweekly meridional march and retreat of the western Pacific subtropical high(WPSH)is particularly evident.As for the extratropics,geopotential height anomalies near Lake Baikal are active.The former is attributed to the intensified biweekly activity of the southwest-northeast oriented EastAsian Pacific wave train(EAP)originating from the tropical western Pacific,while the latter is associated with the biweekly activities of the eastward propagating Eurasia mid-high latitudinal wave train and the westward propagating North Pacific wave train.Why the biweekly activities of these wave trains intensified is further diagnosed from the perspective of thermodynamical forcing and also from the modulation of interannual background on intraseasonal variability.It is found that the strongest recorded convection anchoring over the tropical western Indian Ocean(IO)triggers anomalous descent over the tropical western Pacific,which modulates the biweekly activity of the EAP.Meanwhile,the anomalous diabatic heating over the IO causes changes of the meridional thermodynamic contrast across the IO to the high latitudes,which modulates the extratropical wave trains.A further diagnosis of barotropic kinetic energy conversion suggests that the active occurrence of two extratropical biweekly wave trains is attributed to the increased efficiency of energy conversion from basic flow.The westward propagation of the extratropical North Pacific wave train is attributed to the weakened and northshifted upper-level westerly,which is caused by the SST warmth near the Kuroshio extension.展开更多
基金supported by the National Natural Science Foundation of China[grant number 42025502]the Guangdong Major Project of Basic and Applied Basic Research[grant number 2020B0301030004].
文摘Is the westerly rotation of the lithosphere an ephemeral accidental recent phenomenon or is it a stable process of Earth's geodynamics? The reason why the tidal drag has been questioned as the mechanism determining the lithospheric shift relative to the underlying mantle is the apparent too high viscosity of the asthenosphere. However, plate boundaries asymmetries are a robust indication of the 'westerly'decoupling of the entire Earth's outer lithospheric shell and new studies support lower viscosities in the low-velocity layer(LVZ) atop the asthenosphere. Since the solid Earth tide oscillation is longer in one side relative to the other due to the contemporaneous Moon's revolution, we demonstrate that a non-linear rheological behavior is expected in the lithosphere mantle interplay. This may provide a sort of ratchet favoring lowering of the LVZ viscosity under shear, allowing decoupling in the LVZ and triggering the westerly motion of the lithosphere relative to the mantle.
基金Research supported by Sapienza University of Rome and Miur-Prin2011
文摘The possibility of a net rotation of the lithosphere with respect to the mantle is generally overlooked since it depends on the adopted mantle reference frames, which are arbitrary. We review the geological and geophysical signatures of plate boundaries, and show that they are markedly asymmetric worldwide. Then we compare available reference frames of plate motions relative to the mantle and discuss which is at best able to fit global tectonic data. Different assumptions about the depths of hotspot sources （below or within the asthenosphere, which decouples the lithosphere from the deep mantle） predict different rates of net rotation of the lithosphere relative to the mantle. The widely used no-net-rotation （NNR） reference frame, and low （〈0.2°-0.4°/Ma） net rotation rates （deep hotspots source） predict an average net rotation in which some plates move eastward relative to the mantle （e.g., Nazca）. With fast （〉1°/Ma） net rotation （shallow hotspots source）, all plates, albeit at different velocity, move westerly along a curved trajectory, with a tectonic equator tilted about 30° relative to the geographic equator. This is consistent with the observed global tectonic asymmetries.
基金This study was financed by the grant from the National Research Project for Less Popular Disciplines of China.
文摘Some Western scholars have re-examined the concept of“Chinese medicine”and its knowledge system under the influence of global history research methods in recent years,in an attempt to understand the factors that led to the spread of Chinese medicine around the world,and what kind of Chinese medicine is constituted outside of China.Thus,researchers have studied the initial stage of traditional Chinese medicine(TCM)’s entry into the western world,tracing its roots and observing new knowledge systems formed in the process of cross-cultural communication.Responding to the research of Western scholars,this paper studies the Radicis Chynae(《中国根书简》Letters on Chinese Root),a monograph written by Andreas Vesalius,a famous European anatomist who lived in the 16th century.The author of this article examined the understanding and interpretation of Chinese medicine by the European intelligentsia from 16th to 19th century,investigated the influence of the westward spread of TCM on the scientific revolution and medical progress in Europe,and analyzed its relationship with the rise of Sinology in Europe.This article discusses the knowledge interaction between Chinese medicine and the formation of modern European medicine from the perspective of global history and cross-culture.
基金supported financially by the National Basic Research Program of China[grant number 2014CB953902]the National Natural Science Foundation of China[grant numbers 41275001 and 41475074]
基金Key National Project for Fundamental Research and Development (2009CB421504)National Science Foundation of China (40975032)Special Project for Forecasters in Yunnan Meteorological Bureau (YB200901)
文摘Using data available from the Retrieval System Based on Yearbooks of Tropical Cyclones over the Western North Pacific,NCEP/NCAR reanalysis daily data and observed precipitation data for 1959 to 2007 in Yunnan,a province located in a low-latitude plateau,this work analyzes the climatic characteristics and the corresponding large-scale circulation patterns related to the western North Pacific westward moving TCs(WMTCs).Its impacts on the rainfall in the Yunnan Plateau are studied.Results show that WMTCs happen almost every year,mainly from July to September.It shows a downward trend in decadal variation.Nearly the entire Yunnan area is affected by them but the eastern part experiences the most severe influences.Most of the WMTCs migrate from the South China Sea,primarily make landfall in Hainan and Guangdong and enter the Northern Bay.The tracks of these typhoons can be classified into five categories,in which the most significant impact results from those making landfall in Guangdong.All categories of the tropical cyclones can induce province-wide heavy rainfall in Yunnan.Super typhoons bring about the heaviest and most extensive rainfall over the low-latitude plateau while the associated circulation pattern is marked with a dominant 500 hPa meridional circulation at middle latitudes,an active monsoon depression and Intertropical Convection Zone(ITCZ) at low latitudes and a westward-located South Asia High at 100 hPa,which is favorable for tropical cyclones to travel westward.WMTCs tend to go westward into the interior part of China if the subtropical high extends its westernmost ridge point to the northeast of Yunnan,or expands its periphery anti-cyclonic circulation to the Tibetan Plateau,or merges with the Qinghai-Tibetan high.
基金Supported by the National Natural Science Foundation of China(42075011 and 41605075)。
文摘The westward migration of tropical cyclone(TC)activity has been identified in the western North Pacific(WNP),but the related features and causes remain elusive.Here,based on the best track data from China,Japan,and the US,and the NCEP–NCAR reanalysis data in 1982–2020,we investigate characteristics of the westward migration of the WNP TC activity with various metrics,and reveal possible causes for the migration of TC tracks through analyzing its seasonality and dependence on environmental conditions.The results show that the WNP TCs show significant westward migrations in a number of metrics,including location of tracks,genesis,the first track point at which TC reaches its lifetime-maximum intensity,and the last track point in the TC lifetime.It is found that TC tracks exhibit more significant westward migrations in the easterly steering flow than in the westerly steering flow.Meanwhile,the TC longitude shift shows notable seasonal variations,for which the TCs in the easterlies move further west than those in the westerlies during July–September,vice versa during October–December.The dependence of the westward migration of TC tracks on background steering flow is associated with the different environmental conditions.The westward shift in the westerly steering is mainly due to the reduced vertical wind shear(VWS),while the weakened zonal easterly steering and reduced VWS are both closely related to the westward migration in the easterly steering.These results have important implications for understanding current and future variations in TC longitude shift.
基金This paper is a phased result from a general project for year 2022 entitled"Local Westward Sketching Journey and Cultural Integration-A Study on Wu Zuoren and Han-Tibetan Cultural Exchanges during the Republic of China"(KBYJ2022B002)undertaken by Kangba Culture Research Center,a key research base of social sciences in Sichuan Province.
文摘The nationalization,modernization,and Chinafication of artistic creation are the motivation for pushing forward the further development of art and advocating Chinese culture.During the Comprehensive War of resistance Against Japanese Aggression,the painter Wu Zuoren answered the art community's call of the times and went twice westward to Xizang for sketching;these trips enriched his artistic creation with Tibetan culture and inspired him to some national paintings;he not only changed and diversified his painting style,but also held a series of exhibitions and communication events,which deepened the understanding and love for Tibetan culture among people from home and abroad.Many of his Tibetan paintings,as they spread across China,have gradually become symbols of Chinese culture shared by multiple ethnic groups;these Tibetan paintings not only demonstrate the united image and general status of the Chinese nation but also serve as vivid cases for the study of forging a strong sense of community for the Chinese nation.
文摘It has historically been very difficult to trace the history of the westward transmission of Chinese medicine through the accounts of its protagonists. Many of the early scholars such as Jack Worsley, Dick Van Buren, and Joe Goodman were reluctant to divulge information about the source of their knowledge, or their professional qualifications. Others, such as John Shen and Hong Yuan-bain were early 20th century immigrants who transmitted highly personalized versions of acupuncture and Chinese medicine to select disciples. Eventually, a new class of scholars appeared, including names such as Ted Kaptchuk, Peter Deadman, Nigel Wiseman, William Morris, Peter Eckman, John Mc Donald, Charles Buck, and the late Giovanni Maciocia who looked for answers back in China, developed translation methodologies and terminology, compiled the main textbooks currently in use at TCM colleges, overcame enormous scholastic adversity, developed courses and pursued the regulation and accreditation of TCM in various countries. This special issue synopsizes the path towards the global acculturation of TCM over the last 50 years, the main protagonists, the enormous accomplishments they have achieved for the profession, their philosophy, their clinical perspectives and visions for the future.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 49734140 and 49974014).
文摘The main geomagnetic field models of IGRF1900-2000 are used to study the latitude-dependence of the westward drift in the main field. The results show that the latitude-dependence exists in the magnetic components with different wavelengths (m=1-10). The global-average westward drift rate of the component of m=1 is 0.189°/a with the maximum of 0.295°/a at latitudes 40°-45°. The compo-nent of m=2 has an average drift rate of 0.411°/a with the maximum of 1.305°/a at latitude -60°. As for the compo-nents with further shorter wavelengths, the drift is generally restricted in a limited latitude range, and has many smaller drift rates. This latitude-dependence of westward drift can not be explained by rigid rotation of the earth’s core. The results of this note also show that there is a negative disper-sion in the westward drift, namely the components of long wavelengths drift faster than those of short wavelengths. This dispersion feature is not in agreement with Hide’s MHD model. It is likely needed
基金The Science Foundation of Donghai Laboratory under contract No.DH-2022KF01010the Zhejiang Key Science and Technology Project under contract No.2020C02004+1 种基金the Basic Public Welfare Research Program of Zhejiang Province under contract No.LGF21D010004the Research on Group Ideological and Political Subject Teaching Model of Ocean Remote Sensing under contract No.132.
文摘Taking the advantage of sun glitter(SG)observed from high-resolution satellites Gaofen-1(GF-1)and Gaofen-6(GF-6),a new method named Shield and Vortex 1-2(SAV1-2)for extracting spatial texture information from sun glitter was established.Sea surface texture detail information around Diaoyu Dao and its affiliated islands was extracted using SAV1-2.Meanwhile,the dynamic characteristics of the water environment were analyzed by combining the water color,temperature and dynamic data.The results show the following information.(1)Stable westward shield effect and eastward Karman vortex streets,extracted from SG,appear upstream(westward)and downstream(eastward)of the Diaoyu Dao and its affiliated islands respectively.(2)The dominant direction of the Kuroshio Current in the Diaoyu Dao and its affiliated islands area is east,the Diaoyu Dao and its affiliated islands interacting with Kuroshio,inducing western shield and eastern shelter and wake.Furthermore,wave intervals of the shield in front of the island range from hundreds to thousands of metres,and extend wider than the island itself.(3)Combining with high-resolution sea surface temperature(SST)and chlorophyll a(Chl a)concentration,the directional changes of water color elements are mutually supported and proved with the stable shield(wave packet)effect in the west and vortex street effect in the east.The change of SST upstream of the island(western shield area)is not significant,the temperature in the downstream shelter area decreases slightly,and the SST in the downstream wake area shows a general trend of obvious decrease.The wake area is dominated by Karman vortex streets in shape,supplementing by vortices.The concentration of Chl a in the west shield of island is as low as that in downstream shelter area,while it increases significantly in the downstream wake area with shape in eddy or ribbon.(4)The SAV methods of extracting sea surface texture detail using SG can be widely used in different sea areas and water quality.This paper can provide reference for the protection and development of Diaoyu Dao and its affiliated islands and its surrounding waters.It is suggested that some kind of current buffer,such as marine wind farm,should be established in the western waters of Diaoyu Dao and its affiliated islands to protect the islands,and marine pasture should be developed in the downstream of eastern waters of Diaoyu Dao and its affiliated islands.
基金jointly supported by the National Key Research and Development Program of China(Grant No.2018YFA0606403)the National Natural Science Foundation of China(Grant Nos.41731177 and 41790473)。
文摘During June-July 2020,the strongest recorded mei-yu rainfall occurred in the middle and lower reaches of the Yangtze River.The rainfall processes exhibited an obvious quasi-biweekly(biweekly in brief)variability,and there are altogether five cycles.It is found that the biweekly rainfall cycle mainly arises from the collaborative effects of biweekly variabilities from both the tropics and extratropics.As for the tropics,the biweekly meridional march and retreat of the western Pacific subtropical high(WPSH)is particularly evident.As for the extratropics,geopotential height anomalies near Lake Baikal are active.The former is attributed to the intensified biweekly activity of the southwest-northeast oriented EastAsian Pacific wave train(EAP)originating from the tropical western Pacific,while the latter is associated with the biweekly activities of the eastward propagating Eurasia mid-high latitudinal wave train and the westward propagating North Pacific wave train.Why the biweekly activities of these wave trains intensified is further diagnosed from the perspective of thermodynamical forcing and also from the modulation of interannual background on intraseasonal variability.It is found that the strongest recorded convection anchoring over the tropical western Indian Ocean(IO)triggers anomalous descent over the tropical western Pacific,which modulates the biweekly activity of the EAP.Meanwhile,the anomalous diabatic heating over the IO causes changes of the meridional thermodynamic contrast across the IO to the high latitudes,which modulates the extratropical wave trains.A further diagnosis of barotropic kinetic energy conversion suggests that the active occurrence of two extratropical biweekly wave trains is attributed to the increased efficiency of energy conversion from basic flow.The westward propagation of the extratropical North Pacific wave train is attributed to the weakened and northshifted upper-level westerly,which is caused by the SST warmth near the Kuroshio extension.
