Based on the composite result of six major the intraseasonal variation of the East Asian La Nina events during 1979-2012, the authors reveal summer monsoon (EASM) and summer rainfall in East Asia in La Nino years. D...Based on the composite result of six major the intraseasonal variation of the East Asian La Nina events during 1979-2012, the authors reveal summer monsoon (EASM) and summer rainfall in East Asia in La Nino years. Due to a higher SST over the western Pacific warm pool in the proceeding winter and spring, warm pool convection in summer is enhanced, leading to a cyclonic anomaly in the subtropical western Pacific. As a result, the western Pacific subtropical high is located more northeastward, and the seasonal march in East Asia is thus accelerated.This anomalous pattern tends to change with the seasonal march, with a maximum anomaly in July. Besides, there is less Mei-yu rainfall in the Yangtze River basin, with an earlier start and termination. The rainfall distribution in East Asia during La Nino years is characterized bya zonal pattern of less rainfall in eastern China and more rainfall over the oceanic region of the western Pacific. By comparison, a meridional pattern is found during El Nino years, with less rainfall in the tropics and more rainfall in the subtropics and midlatitudes. Therefore, the influence of La Nino on the EASM cannot be simply attributed to an antisymmetric influence of El Nino.展开更多
Yarsagumba(Ophiocordyceps sinensis), an endemic species to the Himalayas and Tibetan Plateau, is one of the most valuable medicinal mushrooms in the world. In Nepal, it is distributed largely in isolated patches of al...Yarsagumba(Ophiocordyceps sinensis), an endemic species to the Himalayas and Tibetan Plateau, is one of the most valuable medicinal mushrooms in the world. In Nepal, it is distributed largely in isolated patches of alpine grasslands of 3,000-5,000 m elevation. Although it is reported from 27 northernmost districts of Nepal, the local distribution pattern of this species is largely unknown.Furthermore, the collection system and local management regime of this species are not well documented. We conducted a field survey at Dhorpatan Hunting Reserve(DHR) among the different stakeholders in January-June 2012 to assess collection sites, patterns and trends and to understand the management regime. We estimated that about 75 kg of Yarsagumba is collected every year from DHR and the amount has been declining since 2008. To manage the resource, locals have initiated regulating the collection by issuing permits, taxing to the collectors, and monitoring the activities of harvesters with the help of park authorities. The revenue generated at local level from the permits has been used for community developmental activities.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
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
The performances of CMIP5 atmospheric general circulation models (AGCMs) in simulating the western North Pacific subtropical high (WNPSH) in El Nino decaying summers are examined in this study. Results show that m...The performances of CMIP5 atmospheric general circulation models (AGCMs) in simulating the western North Pacific subtropical high (WNPSH) in El Nino decaying summers are examined in this study. Results show that most models can reproduce the spatial pattern of both climatological and anomalous circulation associated with the WNPSH in El Nino decaying summers. Most CMIP5 AGCMs can capture the westward shift of the WNPSH in El Nino decaying summers compared with the climatological location. With respect to the sub-seasonal variation of the WNPSH, the performances of these AGCMs in reproducing the northward jump of the WNPSH are better than simulating the eastward retreat of the WNPSH from July to August. Twenty-one out of twenty-two (20 out of 22) models can reasonably reproduce the northward jump of the WNPSH in El Nino decaying summers (climatology), while only 7 out of 22 (8 out of 22) AGCMs can reasonably reproduce the eastward retreat of the WNPSH in El Nino decaying summers (climatology). In addition, there is a close connection between the climatological WNPSH location bias and that in El Nino decaying summers.展开更多
The correlation between summertime Nino3.4 index and western North Pacific(WNP)summer monsoon index has strikingly enhanced since the early 1990 s,with nonsignificant correlation before the early1990 s but significant...The correlation between summertime Nino3.4 index and western North Pacific(WNP)summer monsoon index has strikingly enhanced since the early 1990 s,with nonsignificant correlation before the early1990 s but significant correlation afterward.This observed interdecadal change around the 1990 s may be associated with more frequent occurrences of central Pacific(CP)El Nino and the interdecadal changes in ENSO-associated SST anomalies.During the post-1990 s period(the pre-1990 s period),highly noticeable tropical Atlantic(Indian)Ocean SST anomalies tend to co-occur with the summertime Nino3.4 SST anomalies.The concurrent tropical Atlantic(Indian)Ocean SST anomalies could constructively reinforce(destructively mitigate)the WNP monsoon circulation anomalies induced by the summertime Nino3.4 SST,thus boosting(muting)the correlation between summertime Nino3.4 SST and WNP monsoon.In addition,the faster decaying pace of preceding-winter El Nino after the 1990 s,which may have been mainly induced by the influences from the spring tropical North Atlantic SST anomalies,could also have contributed to the enhanced correlation between the summertime Nino3.4 index and WNP monsoon.These results suggest that the enhanced influences from the tropical Atlantic SST may have triggered the intensified correlation between summertime ENSO and WNP monsoon since the early 1990 s.展开更多
Natural hazards and their related impacts can have powerful implications for humanity, particularly communities with deep reliance on natural resources. The development of effective early warning systems(EWS) can cont...Natural hazards and their related impacts can have powerful implications for humanity, particularly communities with deep reliance on natural resources. The development of effective early warning systems(EWS) can contribute to reducing natural hazard impacts on communities by improving risk reduction strategies and activities.However, current shortcomings in the conception and applications of EWS undermine risk reduction at the grassroots level. This article explores various pathways to involve local communities in EWS from top-down to more participatory approaches. Based on a literature review and three case studies that outline various levels of participation in EWS in Kenya, Hawai'i, and Sri Lanka, the article suggests a need to review the way EWS are designed and applied, promoting a shift from the traditional expert-driven approach to one that is embedded at the grassroots level and driven by the vulnerable communities. Such a community-centric approach also raises multiple challenges linked to a necessary shift of conception of EWS and highlights the need for more research on pathways for sustainable community engagement.展开更多
Together with success in Cuba and Iran,is bolstering U.S.-Africa relations intended to be the final component of a foreign relations hat trick?Twenty-eight years after his first visit,U.S.President Barack Obama set f...Together with success in Cuba and Iran,is bolstering U.S.-Africa relations intended to be the final component of a foreign relations hat trick?Twenty-eight years after his first visit,U.S.President Barack Obama set foot once more on the soil of Kenya,birthplace of his father and a place which some people believe to be more his hometown than his native Hawaii.展开更多
基金supported by the National Natural Science Foundation of China[grant number 41475052]
文摘Based on the composite result of six major the intraseasonal variation of the East Asian La Nina events during 1979-2012, the authors reveal summer monsoon (EASM) and summer rainfall in East Asia in La Nino years. Due to a higher SST over the western Pacific warm pool in the proceeding winter and spring, warm pool convection in summer is enhanced, leading to a cyclonic anomaly in the subtropical western Pacific. As a result, the western Pacific subtropical high is located more northeastward, and the seasonal march in East Asia is thus accelerated.This anomalous pattern tends to change with the seasonal march, with a maximum anomaly in July. Besides, there is less Mei-yu rainfall in the Yangtze River basin, with an earlier start and termination. The rainfall distribution in East Asia during La Nino years is characterized bya zonal pattern of less rainfall in eastern China and more rainfall over the oceanic region of the western Pacific. By comparison, a meridional pattern is found during El Nino years, with less rainfall in the tropics and more rainfall in the subtropics and midlatitudes. Therefore, the influence of La Nino on the EASM cannot be simply attributed to an antisymmetric influence of El Nino.
基金the Dhorpatan Hunting Reserve Office and Department of National Parks and Wildlife Conservation, Nepal for the financial and logistic support to conduct this study
文摘Yarsagumba(Ophiocordyceps sinensis), an endemic species to the Himalayas and Tibetan Plateau, is one of the most valuable medicinal mushrooms in the world. In Nepal, it is distributed largely in isolated patches of alpine grasslands of 3,000-5,000 m elevation. Although it is reported from 27 northernmost districts of Nepal, the local distribution pattern of this species is largely unknown.Furthermore, the collection system and local management regime of this species are not well documented. We conducted a field survey at Dhorpatan Hunting Reserve(DHR) among the different stakeholders in January-June 2012 to assess collection sites, patterns and trends and to understand the management regime. We estimated that about 75 kg of Yarsagumba is collected every year from DHR and the amount has been declining since 2008. To manage the resource, locals have initiated regulating the collection by issuing permits, taxing to the collectors, and monitoring the activities of harvesters with the help of park authorities. The revenue generated at local level from the permits has been used for community developmental activities.
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 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 Natural Science Foundation of China[grant numbers 41475052,41405058]China Postdoctoral Science Foundation[grant number 2015M571095]Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA11010403]
文摘The performances of CMIP5 atmospheric general circulation models (AGCMs) in simulating the western North Pacific subtropical high (WNPSH) in El Nino decaying summers are examined in this study. Results show that most models can reproduce the spatial pattern of both climatological and anomalous circulation associated with the WNPSH in El Nino decaying summers. Most CMIP5 AGCMs can capture the westward shift of the WNPSH in El Nino decaying summers compared with the climatological location. With respect to the sub-seasonal variation of the WNPSH, the performances of these AGCMs in reproducing the northward jump of the WNPSH are better than simulating the eastward retreat of the WNPSH from July to August. Twenty-one out of twenty-two (20 out of 22) models can reasonably reproduce the northward jump of the WNPSH in El Nino decaying summers (climatology), while only 7 out of 22 (8 out of 22) AGCMs can reasonably reproduce the eastward retreat of the WNPSH in El Nino decaying summers (climatology). In addition, there is a close connection between the climatological WNPSH location bias and that in El Nino decaying summers.
基金supported by the National Key Research and Development Program of China [grant number2018YFC1506903]the National Natural Science Foundation of China [grant number 41776031]+2 种基金the Guangdong Natural Science Foundation [grant number 2015A030313796]the 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 correlation between summertime Nino3.4 index and western North Pacific(WNP)summer monsoon index has strikingly enhanced since the early 1990 s,with nonsignificant correlation before the early1990 s but significant correlation afterward.This observed interdecadal change around the 1990 s may be associated with more frequent occurrences of central Pacific(CP)El Nino and the interdecadal changes in ENSO-associated SST anomalies.During the post-1990 s period(the pre-1990 s period),highly noticeable tropical Atlantic(Indian)Ocean SST anomalies tend to co-occur with the summertime Nino3.4 SST anomalies.The concurrent tropical Atlantic(Indian)Ocean SST anomalies could constructively reinforce(destructively mitigate)the WNP monsoon circulation anomalies induced by the summertime Nino3.4 SST,thus boosting(muting)the correlation between summertime Nino3.4 SST and WNP monsoon.In addition,the faster decaying pace of preceding-winter El Nino after the 1990 s,which may have been mainly induced by the influences from the spring tropical North Atlantic SST anomalies,could also have contributed to the enhanced correlation between the summertime Nino3.4 index and WNP monsoon.These results suggest that the enhanced influences from the tropical Atlantic SST may have triggered the intensified correlation between summertime ENSO and WNP monsoon since the early 1990 s.
文摘Natural hazards and their related impacts can have powerful implications for humanity, particularly communities with deep reliance on natural resources. The development of effective early warning systems(EWS) can contribute to reducing natural hazard impacts on communities by improving risk reduction strategies and activities.However, current shortcomings in the conception and applications of EWS undermine risk reduction at the grassroots level. This article explores various pathways to involve local communities in EWS from top-down to more participatory approaches. Based on a literature review and three case studies that outline various levels of participation in EWS in Kenya, Hawai'i, and Sri Lanka, the article suggests a need to review the way EWS are designed and applied, promoting a shift from the traditional expert-driven approach to one that is embedded at the grassroots level and driven by the vulnerable communities. Such a community-centric approach also raises multiple challenges linked to a necessary shift of conception of EWS and highlights the need for more research on pathways for sustainable community engagement.
文摘Together with success in Cuba and Iran,is bolstering U.S.-Africa relations intended to be the final component of a foreign relations hat trick?Twenty-eight years after his first visit,U.S.President Barack Obama set foot once more on the soil of Kenya,birthplace of his father and a place which some people believe to be more his hometown than his native Hawaii.