Parallel Comparison of the 1982/83,1997/98 and 2015/16 Super El Nios and Their Effects on the Extratropical Stratosphere     

Jian RAO  Rongcai REN 《大气科学进展》2017,34(9):1121-1133

This study uses multiple sea surface temperature(SST) datasets to perform a parallel comparison of three super El Ni os and their effects on the stratosphere. The results show that, different from ordinary El Ni os, warm SST anomalies appear earliest in the western tropical Pacific and precede the super El Ni o peak by more than 18 months. In the previous winter,relative to the mature phase of El Ni o, as a precursor, North Pacific Oscillation-like circulation anomalies are observed. A Pacific–North America(PNA) teleconnection appears in the extratropical troposphere during the mature phase, in spite of the subtle differences between the intensities, as well as the zonal position, of the PNA lobes. Related to the negative rainfall response over the tropical Indian Ocean, the PNA teleconnection in the winter of 1997/98 is the strongest among the three super El Ni os. The northern winter stratosphere shows large anomalies in the polar cap temperature and the circumpolar westerly, if the interferences from other factors are linearly filtered from the circulation data. Associated with the positive PNA response in a super El Ni o winter, positive polar cap temperature anomalies and circumpolar easterly anomalies,though different in timing, are also observed in the mature winters of the three super El Ni os. The stratospheric polar vortex in the next winter relative to the 1982/83 and 1997/98 events is also anomalously weaker and warmer, and the stratospheric circulation conditions remain to be seen in the coming winter following the mature phase of the 2015/16 event.  相似文献   

美国海岸海洋管理的法律体系与实践   总被引：5，自引：0，他引：5  

张灵杰 《海洋地质前沿》2002,18(3):28-33

从四个阶段划分了美国海岸海洋管理的立法过程，阐述了美国海岸海洋管理法律体系的若干特征与存在的问题，并从体制、制度、政策等方面评述了海岸海洋的管理活动，最后分析了美国当前海岸海洋管理立法局长的新趋势。  相似文献   

Lunar rhythms in the egg hatching of the subtidal crustacean: Callinectes arcuatus Ordway (Decapoda: Brachyura)     

M. C. DeVries  C. E. Epifanio  A. I. Dittel 《Estuarine, Coastal and Shelf Science》1983,17(6):717-724

The Gulf of Nicoya, an estuary on the Pacific coast of Central America, contains a large population of the portunid crab Callinectes arcuatus. Results of a 12 month survey indicated that spawning activity occurs throughout the year, but with a distinct peak during the five-month dry season (December-April). Mature females were most prevalent in the upper regions of the gulf during the rainy season and appeared to migrate to the lower gulf to spawn during the dry season. Patterns of spawning and apparent migration differed from those reported in an earlier study of C. arcuatus along the Pacific coast of Mexico.  相似文献   

拉丁方正交完全系和常用正交表的简捷构造法   总被引：1，自引：0，他引：1  

刘长安 《海洋湖沼通报》1995,(4):1-8

本文根据两个同阶拉丁方正交的定义和正交表的定义以及有关的数学理论，编制出拉丁方正交完全系和常用正交表的简捷构造法，提供给实验工作者使用并以此加深对拉丁方设计和正交设计的理解和掌握。设正整数ｍ〉２，本文在以下两种情形分别使用不同的方法构造ｍ阶拉丁方正交完全系：（１）ｍ为质数：以自然顺序的第１列为起点，从第２列开始，在列中依次进行数置换；（２）ｍ为质数幂：首先构造一个特定的标准拉丁方作为起点，然后从第  相似文献   

A tree‐ring chronology and paleoclimate record for the Younger Dryas–Early Holocene transition from northeastern North America     

《第四纪科学杂志》2017,32(3):341-346

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Estimation by photogrammetry of the glacier recession on the Cotopaxi Volcano (Ecuador) between 1956 and 1997 / Estimation par photogrammétrie de la récession glaciaire sur le Volcan Cotopaxi (Equateur) entre 1956 et 1997     

《水文科学杂志》2013,58(6)

Abstract

Aerial photographs of the Cotopaxi Volcano ice cap dating from 1956 to 1997 were used to quantify the evolution of the surface area. Results were obtained using precise stereoscopic methods that give the most accurate information. In addition four specific glacier tongues were investigated in detail to measure the ice mass lost between 1976 and 1997. Surprisingly, the bedrock morphology is shown to be very irregular and this explains a large extent of the variability found in the ice losses. The results show that glaciers stagnated from 1956 to 1976 and lost about 30% of their surface area between 1976 and 1997. Slope exposure did not seem to have any significant effect since all the glaciers of the volcano retreated in the same proportion. In accordance with specific measurements performed on the nearby Antizana 15 Glacier, it is suggested that the strong recession observed after 1976 was associated with increasing melting conditions which have occurred repeatedly during the intense/long-duration warm ENSO phases.  相似文献   

The sudestadas: a hydro-meteorological phenomenon that affects river pollution (River Luján,South America)     

《水文科学杂志》2013,58(4):702-712

Abstract

The “sudestadas” are short-term hydro-meteorological phenomena that produce a “hydraulic plug”, preventing the normal drainage of the water courses in the Río de la Plata Estuary. The purpose of this study was to analyse the influence of the sudestadas on the water quality of the Lower River Luján, which discharges into the Río de la Plata Estuary (59°37′W; 34°43′S). Samplings were conducted from November 1998 to July 2001 at six sites on the lower stretch of river. Physical and chemical variables were measured and a nonparametric test was applied to each variable, grouping samples affected and non-affected by sudestadas, which further diminish the water quality of the river. The frequency and intensity of sudestadas are predicted to increase as a consequence of the Earth's warming; thus, this research suggests that the environmental risk produced by the effects of global change, will be greater.  相似文献   

Statistical testing of a new testate amoeba‐based transfer function for water‐table depth reconstruction on ombrotrophic peatlands in north‐eastern Canada and Maine,United States     

Matthew J. Amesbury  Gunnar Mallon  Dan J. Charman  Paul D. M. Hughes  Robert K. Booth  Timothy J. Daley  Michelle Garneau 《第四纪科学杂志》2013,28(1):27-39

Proxy reconstructions of climatic parameters developed using transfer functions are central to the testing of many palaeoclimatic hypotheses on Holocene timescales. However, recent work shows that the mathematical models underpinning many existing transfer functions are susceptible to spatial autocorrelation, clustered training set design and the uneven sampling of environmental gradients. This may result in over‐optimistic performance statistics or, in extreme cases, a lack of predictive power. A new testate amoeba‐based transfer function is presented that fully incorporates the new recommended statistical tests to address these issues. Leave‐one‐out cross‐validation, the most commonly applied method in recent studies to assess model performance, produced over‐optimistic performance statistics for all models tested. However, the preferred model, developed using weighted averaging with tolerance downweighting, retained a predictive capacity equivalent to other published models even when less optimistic performance statistics were chosen. Application of the new statistical tests in the development of transfer functions provides a more thorough assessment of performance and greater confidence in reconstructions based on them. Only when the wider research community have sufficient confidence in transfer function‐based proxy reconstructions will they be commonly used in data comparison and palaeoclimate modelling studies of broader scientific relevance. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Sustainable agricultural intensification or Jevons paradox? The role of public governance in tropical South America     

M.G. Ceddia  S. Sedlacek  N.O. Bardsley  S. Gomez-y-Paloma 《Global Environmental Change》2013,23(5):1052-1063

The process of global deforestation calls for urgent attention, particularly in South America where deforestation rates have failed to decline over the past 20 years. The main direct cause of deforestation is land conversion to agriculture. We combine data from the FAO and the World Bank for six tropical Southern American countries over the period 1970–2006, estimate a panel data model accounting for various determinants of agricultural land expansion and derive elasticities to quantify the effect of the different independent variables. We investigate whether agricultural intensification, in conjunction with governance factors, has been promoting agricultural expansion, leading to a “Jevons paradox”. The paradox occurs if an increase in the productivity of one factor (here agricultural land) leads to its increased, rather than decreased, utilization. We find that for high values of our governance indicators a Jevons paradox exists even for moderate levels of agricultural productivity, leading to an overall expansion of agricultural area. Agricultural expansion is also positively related to the level of service on external debt and population growth, while its association with agricultural exports is only moderate. Finally, we find no evidence of an environmental Kuznets curve, as agricultural area is ultimately positively correlated to per-capita income levels.  相似文献   

A pollen–climate calibration from western Patagonia for palaeoclimatic reconstructions     

Vincent Montade  Odile Peyron  Charly Favier  Jean Pierre Francois  Simon G. Haberle 《第四纪科学杂志》2019,34(1):76-86

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