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1.
基于SPEI指数的兰州干旱特征与气候指数的关系 总被引：2，自引：0，他引：2
基于1961~2012年逐日气象及同期4个气候因子资料系列,采用标准化降水蒸散发指数(SPEI)定量描述兰州地区干旱状况,利用M-K检验分析了该地干旱变化趋势,采用皮尔逊相关系数法以及交叉小波变换法研究了SPEI与北大西洋涛动(NAO)、北极振荡(AO)、太平洋十年涛动(PDO)以及厄尔尼诺-南方涛动(ENSO)四个气候因子之间的关系。研究结果表明:干旱指数SPEI在月、春、夏、秋及年尺度上均呈显著下降趋势、冬季增长趋势不显著,未来兰州春、夏和秋季缺水有加重趋势,冬季有变湿润倾向;SPEI与PDO、ENSO在秋季呈显著负相关;ENSO主要影响干旱短周期的年际变化;干旱与PDO和AO呈滞后的负相关关系,两指数主要影响较长周期干旱的年际和年代际变化。 相似文献
2.
利用模糊C-均值聚类算法、皮尔逊相关和滑动相关分析等方法,对珠江流域做了气候一致性分析,在此基础上,研究了珠江流域不同分区年降水和干湿季降水变化的时空特征,分析了区域干湿变化与厄尔尼诺-南方涛动(ENSO)、北大西洋涛动(NAO)、印度洋偶极子(IOD)和太平洋10年涛动(PDO)等主要气候因子的遥相关关系,探讨了珠江流域干湿变化的气候成因。在此基础上,进一步研究上述气候指标对不同时间尺度干湿变化影响的平稳性与差异性。除此之外,还研究了气候指标的冷暖期对基于6个月SPI值的珠江流域干湿状态的影响。研究表明:(1)IOD、NAO和ENSO分别是导致珠江流域年降水、湿季降水和干季降水发生变化的主要影响因素,且对当年及下一年降水的影响是相反的。(2)珠江流域不同时间尺度的降水与对其有显著影响的气候指标(年降水与IOD,湿季降水与NAO,干季降水与ENSO),两者之间不同时期的滑动相关往往具有较强的相关性和前后相关一致性。(3)各气候指标对珠江流域不同时间尺度降水的影响在空间分布上不太均匀。(4)不同位相下气候指标对珠江流域干湿状态的影响存在较大差异。总体而言,当处于各气候指标暖期时珠江流域出现湿润期的概率较冷期时更大且在空间分布上更均匀。 相似文献
3.
使用动态植被陆面模式AVIM2,以NCEP (National Centers for Environmental Prediction)再分析气象资料作为大气强迫场,模拟了1953-2004年全球陆地生态系统净初级生产力(NPP)和净生态系统生产力(NEP) 的空间分布及时间变化特征。结果得到,1953-2004年陆地生态系统NPP和NEP全球总量52 a的C平均值分别为65 Pg/a和1.2 Pg/a,NPP呈明显的上升趋势,而NEP的上升趋势不明显。虽然NPP和NEP的年代际增长趋势不同,但是在20世纪70年代中期,NPP和NEP的年代际变化都出现了一个明显的突变,突变点后的增长趋势都没有之前的增长趋势高。这是由于太平洋的年代际振荡(PDO)冷暖位相影响了厄尔尼诺与南方涛动（El Nin~o Southern Oscillation,ENSO)的年代际变化,对NPP和NEP的年代际变化也产生了重要的影响。1976年以前PDO处于冷位相年,增加了ENSO冷位相的强度和频率,使热带地区的气候偏凉爽湿润,从而利于NPP和NEP趋势增长,而1976年以后PDO进入暖位相年,El Nin~o发生频繁,赤道地区多为干热的气候异常,会降低NPP和NEP的增长趋势。 相似文献
4.
Freshwater delivery is an important factor determining estuarine character and health and may be influenced by large-scale climate oscillations. Variability in freshwater delivery (precipitation and discharge) to the Altamaha River estuary (GA, USA) was examined in relation to indices for several climate signals: the Bermuda High Index (BHI), the Southern Oscillation Index (SOI), the Improved El Niño Modoki Index (IEMI), the North Atlantic Oscillation (NAO), the Atlantic Multidecadal Oscillation (AMO), the Pacific Decadal Oscillation (PDO), and the Pacific/North American Pattern (PNA). Discharge to this estuary has been linked to key ecosystem properties (e.g., salinity regime, water residence time, nutrient inputs, and marsh processes), so understanding how climate patterns affect precipitation and river discharge will help elucidate how the estuarine ecosystem may respond to climate changes. Precipitation patterns in the Altamaha River watershed were described using empirical orthogonal functions (EOFs) of the combined multidecadal time series of precipitation at 14 stations. The first EOF (67 % of the variance) was spatially uniform, the second EOF (11 %) showed a spatial gradient along the long axis of the watershed (NW–SE), and the third EOF (6 %) showed a NE–SW pattern. We compared the principal components (PCs) associated with these EOFs, monthly standardized anomalies of Altamaha River discharge at the gauge closest to the estuary, and the climate indices. Complex, seasonally alternating patterns emerged. The BHI was correlated with June–January discharge and precipitation PC 1. The SOI was correlated with January–April discharge and precipitation PC 2, and also weakly correlated with PC 1 in November–December. The AMO was correlated with river discharge and precipitation PC 3 mainly in December–February and June. The correlation patterns of precipitation PCs with PDO and PNA were similar to those with SOI, but weaker. There were no consistent relationships with two NAO indices or IEMI. Connections between climate signals and estimates of nutrient loading were consistent with the connections to discharge. The occurrence of tropical storms in the region was strongly related to the BHI but not to the other climate indices, possibly representing the influence of storm tracking more than the rate of storm formation. Comparison with the literature suggests that the patterns found may be typical of southeastern USA estuaries but are likely to be different from those outside the region. 相似文献
5.
Tsegaye Tadesse Donald A. Wilhite Sherri K. Harms Michael J. Hayes Steve Goddard 《Natural Hazards》2004,33(1):137-159
Drought has an impact on many aspects of society. To help decision makers reduce the impacts of drought, it is important to
improve our understanding of the characteristics and relationships of atmospheric and oceanic parameters that cause drought.
In this study, the use of data mining techniques is introduced to find associations between drought and several oceanic and
climatic indices that could help users in making knowledgeable decisions about drought responses before the drought actually
occurs. Data mining techniques enable users to search for hidden patterns and find association rules for target data sets
such as drought episodes. These techniques have been used for commercial applications, medical research, and telecommunications,
but not for drought. In this study, two time-series data mining algorithms are used in Nebraska to illustrate the identification
of the relationships between oceanic parameters and drought indices. The algorithms provide flexibility in time-series analyses
and identify drought episodes separate from normal and wet conditions, and find relationships between drought and oceanic
indices in a manner different from the traditional statistical associations. The drought episodes were determined based on
the Standardized Precipitation Index (SPI) and Palmer Drought Severity Index (PDSI). Associations were observed between drought
episodes and oceanic and atmospheric indices that include the Southern Oscillation Index (SOI), the Multivariate ENSO Index
(MEI), the Pacific/North American (PNA) index, the North Atlantic Oscillation (NAO) Index, and the Pacific Decadal Oscillation
(PDO) Index. The experimental results showed that among these indices, the SOI, MEI, and PDO have relatively stronger relationships
with drought episodes over selected stations in Nebraska. Moreover, the study suggests that data mining techniques can help
us to monitor drought using oceanic indices as a precursor of drought. 相似文献
6.
Steven N. Bacon Eric V. McDonald Todd G. Caldwell Graham K. Dalldorf 《Quaternary Research》2010,73(3):425-438
The integration of geomorphic mapping, soil stratigraphy, and radiocarbon dating of alluvial deposits offers insight to the timing, magnitude, and paleoclimatic context of Holocene fan sedimentation near Yuma, Arizona. Mapping of 3400 km2 indicates about 10% of the area aggraded in the late Holocene and formed regionally extensive alluvial fan and alluvial plain cut-and-fill terraces. Fan deposits have weakly developed gravelly soils and yielded a date of 3200–2950 cal yr BP from carbonized wood. Alluvial plain deposits have weakly developed buried sandy soils and provided a date of 2460–2300 cal yr BP from a terrestrial snail shell. Precipitation records were analyzed to form historical analogues to the late Holocene aggradation and to consider the role of climatic variability and extreme hydrologic events as drivers of the sedimentation. The historical precipitation record indicates numerous above-average events correlated to the Southern Oscillation Index (SOI) in the region, but lacks any significant reactivation of alluvial fan surfaces. The timing of aggradation from 3200 to 2300 cal yr BP correlates well with other paleoclimatic proxy records in the southwestern U.S. and eastern Pacific region, which indicate an intensification of the El Niño-Southern Oscillation (ENSO) climatic pattern and rapid climate change during this period. 相似文献
7.
Flamingos,salt lakes and volcanoes: hunting for evidence of past climate change on the high Altiplano of Bolivia 
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下载免费PDF全文 Hidden within the vast Bolivian Altiplano are archives of past climate change in the form of remarkable carbonate rocks surrounding lakes long since disappeared. Beyond the Salar de Uyuni, the largest salt flat in the world, lies a relatively untouched realm of volcanoes and salt lakes. Ancient shorelines from intervals in the Altiplano history, when large lakes were more abundant, may hold important information about a time when the climate in this region was punctuated by much wetter phases before present day aridity took a hold. Previous studies in this region have reconstructed robust chronological timelines for such events and highlight two large lake phases over the last 18 thousand years (the Tauca and Coipasa lake phases); however higher resolution climate data are scarce. Current studies on climate proxies from smaller lakes in southern Bolivia may shed light on some of these higher resolution climate events including El Niño–Southern Oscillation (ENSO) events. Laminated tufa found around the palaeoshorelines of the West Lípez Lakes is one such proxy, and can be analysed to investigate the potential roles of annual versus shorter‐term climatic variation in the evolving Altiplano climate at the time. 相似文献
8.
Jimmy Byakatonda B P Parida Piet K Kenabatho D B Moalafhi 《Journal of Earth System Science》2018,127(2):25
Arid and semi-arid environments have been identified with locations prone to impacts of climate variability and change. Investigating long-term trends is one way of tracing climate change impacts. This study investigates variability through annual and seasonal meteorological time series. Possible inhomogeneities and years of intervention are analysed using four absolute homogeneity tests. Trends in the climatic variables were determined using Mann–Kendall and Sen’s Slope estimator statistics. Association of El Niño Southern Oscillation (ENSO) with local climate is also investigated through multivariate analysis. Results from the study show that rainfall time series are fully homogeneous with 78.6 and 50% of the stations for maximum and minimum temperature, respectively, showing homogeneity. Trends also indicate a general decrease of 5.8, 7.4 and 18.1% in annual, summer and winter rainfall, respectively. Warming trends are observed in annual and winter temperature at 0.3 and 1.5% for maximum temperature and 1.7 and 6.5% for minimum temperature, respectively. Rainfall reported a positive correlation with Southern Oscillation Index (SOI) and at the same time negative association with Sea Surface Temperatures (SSTs). Strong relationships between SSTs and maximum temperature are observed during the El Niño and La Niña years. These study findings could facilitate planning and management of agricultural and water resources in Botswana. 相似文献
9.
Historical documents and newspapers from Mexican Pacific states (north of 14° N) were reviewed to determine the incidence of landfalling tropical cyclones from 1850 to 1949, prior to the start of the United States National Hurricane Center database. The reviewed documents are only found in Mexican repositories at national, state and municipal level and the systematic search embarked upon in this study yielded valuable information that cannot be found elsewhere. Atime series of landfall was reconstructed back to 1850, indicating active and quiet periods. An average of 1.8 ± 1.6 landfalls per year is determined from the time series for 1850-2010. When the series is limited to 1880-2010, eliminating the first 30 years that may have some undercounting, the average increases to 2.1 ± 1.6 cases per year. Spectral and wavelet analysis of the 161 years of landfalling tropical cyclones indicates that the Pacific Decadal Oscillation (PDO) modulates the activity. The influence of El Niño/Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) on the landfall frequency may be present throughout the reconstruction period but both oscillations have lower correlations compared to that from the PDO. 相似文献
10.
ENSO(厄尔尼诺-南方涛动)事件的发生会影响区域气候变化。通过对青海东部地区5个站点1959~2005年的降水、气温资料、干燥度和海表温度距平(SSTA)与南方涛动指数(SOI)的月序列进行相关性分析和周期性谱分析,探讨了区域气候变化与ENSO事件的关系。结果表明,1959~2005年青海省东部地区气候趋于暖干,并且冬春季变化趋势显著;暖事件的发生对该区域降水、气温及干燥度的变化影响较大,且气温对ENSO事件的响应要大于降水;ENSO事件对该区域的气候变化有两到三个月的影响期,EI Nino事件的发生对当月的影响较大,而La Nina事件的发生对该区域有两到三个月的持续影响期;降水距平及气温距平与ENSO事件存在短期相同的变化趋势,且该地区气候变化受南方涛动影响明显。 相似文献
11.
John E. Kutzbach 《Quaternary Research》1976,6(4):471-480
The climate system consists of the atmosphere, the oceans, the cryosphere (land ice, snow, sea ice), the lithosphere, and the biomass. The behavior of the individual components of the system is governed by processes occurring over a broad range of time and space scales. The components are coupled by physical, biological, and chemical processes, and the coupled system seems capable of undergoing fluctuations on all time scales. In addition to these “internal” climatic processes, external processes (such as variability in the solar irradiance or human activities) must also be considered. Space and time scales of climatic variability are reviewed, with emphasis on the Holocene. Regional patterns of climatic variability may be associated with changes in the amplitude and longitudinal position of the long waves in the westerlies of midlatitudes, and with changes in the intensity and latitude of meridional circulation features such as the Hadley cell. Possible examples of this are mentioned. The variance spectrum of climatic time series is described and certain implications for climate modeling are suggested. 相似文献
12.
Sorensen James P. R. Davies Jeff Ebrahim Girma Y. Lindle John Marchant Ben P. Ascott Matthew J. Bloomfield John P. Cuthbert Mark O. Holland Martin Jensen K. H. Shamsudduha M. Villholth Karen G. MacDonald Alan M. Taylor Richard G. 《Hydrogeology Journal》2021,29(8):2773-2787
There is a scarcity of long-term groundwater hydrographs from sub-Saharan Africa to investigate groundwater sustainability, processes and controls. This paper presents an analysis of 21 hydrographs from semi-arid South Africa. Hydrographs from 1980 to 2000 were converted to standardised groundwater level indices and rationalised into four types (C1–C4) using hierarchical cluster analysis. Mean hydrographs for each type were cross-correlated with standardised precipitation and streamflow indices. Relationships with the El Niño–Southern Oscillation (ENSO) were also investigated. The four hydrograph types show a transition of autocorrelation over increasing timescales and increasingly subdued responses to rainfall. Type C1 strongly relates to rainfall, responding in most years, whereas C4 notably responds to only a single extreme event in 2000 and has limited relationship with rainfall. Types C2, C3 and C4 have stronger statistical relationships with standardised streamflow than standardised rainfall. C3 and C4 changes are significantly (p <?0.05) correlated to the mean wet season ENSO anomaly, indicating a tendency for substantial or minimal recharge to occur during extreme negative and positive ENSO years, respectively. The range of different hydrograph types, sometimes within only a few kilometres of each other, appears to be a result of abstraction interference and cannot be confidently attributed to variations in climate or hydrogeological setting. It is possible that high groundwater abstraction near C3/C4 sites masks frequent small-scale recharge events observed at C1/C2 sites, resulting in extreme events associated with negative ENSO years being more visible in the time series.
相似文献13.
The possible impact of El Niño-Southern Oscillation (ENSO) and macrocirculation patterns (CPs) on local precipitation are examined and analyzed here under climate change conditions. First the relationship between the input and output variables under present conditions is established using two models, a fuzzy rule-based model (FRBM) and a multivariate linear regression model (MLRM), then this historical relationship is extended under climate change conditions. The input variables for these models consist of lagged ENSO-data (represented by the Southern Oscillation Index, SOI) and 500 hPa height data clustered into macrocirculation patterns over the western United States, while the output is an estimate of monthly local precipitation at selected Arizona stations. To overcome the lack of SOI data under climate change, several scenarios are constructed by perturbing the historical SOI data in a design of experiments framework. The results of the experimental design show that, in general, the precipitation amount seems to decrease under climate change. While the stations and months have differences, as expected, the perturbed scenarios do not show significant differences. 相似文献
14.
本文试图介绍发生在非冰期,主要是全新世的突然气候变化研究所取得的进展,包括山地冰川和深海沉积物所记录的全新世突然气候变化,季风和干旱气候突然变化,以及突然气候变化与太阳变化的关系。太阳变化对整个全新世气候变化的影响似乎正愈来愈明晰起来。 相似文献
15.
Thomas M. Soniat Eileen E. Hofmann John M. Klinck Eric N. Powell 《International Journal of Earth Sciences》2009,98(1):99-114
The eastern oyster (Crassostrea virginica) is affected by two protozoan parasites, Perkinsus marinus which causes Dermo disease and Haplosporidium nelsoni which causes MSX (Multinucleated Sphere Unknown) disease. Both diseases are largely controlled by water temperature and salinity and thus are potentially sensitive to climate variations resulting from the El Niño-Southern Oscillation (ENSO), which influences climate along the Gulf of Mexico coast, and the North Atlantic Oscillation (NAO), which influences climate along the Atlantic coast of the United States. In this study, a 10-year time series of temperature and salinity and P. marinus infection intensity for a site in Louisiana on the Gulf of Mexico coast and a 52-year time series of air temperature and freshwater inflow and oyster mortality from Delaware Bay on the Atlantic coast of the United States were analyzed to determine patterns in disease and disease-induced mortality in C. virginica populations that resulted from ENSO and NAO climate variations. Wavelet analysis was used to decompose the environmental, disease infection intensity and oyster mortality time series into a time–frequency space to determine the dominant modes of variability and the time variability of the modes. For the Louisiana site, salinity and Dermo disease infection intensity are correlated at a periodicity of 4 years, which corresponds to ENSO. The influence of ENSO on Dermo disease along the Gulf of Mexico is through its effect on salinity, with high salinity, which occurs during the La Niña phase of ENSO at this location, favoring parasite proliferation. For the Delaware Bay site, the primary correlation was between temperature and oyster mortality, with a periodicity of 8 years, which corresponds to the NAO. Warmer temperatures, which occur during the positive phase of the NAO, favor the parasites causing increased oyster mortality. Thus, disease prevalence and intensity in C. virginica populations along the Gulf of Mexico coast is primarily regulated by salinity, whereas temperature regulates the disease process along the United States east coast. These results show that the response of an organism to climate variability in a region is not indicative of the response that will occur over the entire range of a particular species. This has important implications for management of marine resources, especially those that are commercially harvested. 相似文献
16.
古里雅冰芯气候记录对ENSO事件的响应 总被引：10，自引：4，他引：6
ENSO现象是一个产生于大尺度海-气相互作用的全球事件, 它是影响全球中低纬度大部分地区气候年际变化的一个重要的因子. 通过高通滤波法、累积异常法以及非参数检验等方法, 对古里雅冰芯中所记录的气候信息与ENSO事件进行相关分析表明, 在厄尔尼诺年, 古里雅冰芯中记录的降水量显著减少, 但对于δ18O而言, 虽然也在厄尔尼诺年偏低, 但未达到显著性水平. 相似文献
17.
Larry Benson Braddock LinsleyJoe Smoot Scott MensingSteve Lund Scott StineAndre Sarna-Wojcicki 《Quaternary Research》2003,59(2):151-159
Mono Lake sediments have recorded five major oscillations in the hydrologic balance between A.D. 1700 and 1941. These oscillations can be correlated with tree-ring-based oscillations in Sierra Nevada snowpack. Comparison of a tree-ring-based reconstruction of the Pacific Decadal Oscillation (PDO) index (D’Arrigo et al., 2001) with a coral-based reconstruction of Subtropical South Pacific sea-surface temperature (Linsley et al., 2000) indicates a high degree of correlation between the two records during the past 300 yr. This suggests that the PDO has been a pan-Pacific phenomena for at least the past few hundred years. Major oscillations in the hydrologic balance of the Sierra Nevada correspond to changes in the sign of the PDO with extreme droughts occurring during PDO maxima. Four droughts centered on A.D. 1710, 1770, 1850, and 1930 indicate PDO-related drought reoccurrence intervals ranging from 60 to 80 yr. 相似文献
18.
相关函数分析表明,河北围场的油松年轮宽度指数与 5～6月平均温度显著相关,在此基础上,设计转换方程,重建了该地区1884年至2002年当年5月至6月的平均温度,重建序列的方差解释量达到43.7%(调整自由度后为41.3%)。重建温度序列表明,温度低于多年(1884～2002年)平均温度的时段主要有 1897～1901年、1913～1923年、1949～1978年和 1992～1995年; 高于多年平均温度的时段主要有 1884～1896年、1902～1912年、1924～1942年和 1979～1992年。重建的温度序列具有较大的区域代表性,它与陕西南五台 5～7月温度显著相关,年际尺度上相关系数为r＝0.18(N＝119,p<0.05),它也与由历史文献记录划分的大同北京二地旱涝指数及亚洲太平洋年代际涛动指数(PDO)均显著相关,表明重建序列在一定程度上反映了大范围的气候变化状况。 相似文献
19.
Cédric Gaucherel 《Comptes Rendus Geoscience》2004,336(3):175-185
El Niño/Southern Oscillation (ENSO) is well known to have a worldwide impact, in particular on streamflows. As an illustration, we found a good correlation (～0.47, 5-month time delay) between the ENSO activity and the discharge of the main rivers in French Guiana. However, this calculation was made between climatic and hydrological processes at ‘isolated precise moments’. Using a new method of time series analysis, we considered the ENSO and Atlantic Ocean/river discharge correlation integrated over time. This method shows, with more than 99% confidence level, new possible delayed and combined influences between the phenomena (respectively ～20 and 40 months for ENSO and Atlantic Ocean influences). To cite this article: C. Gaucherel, C. R. Geoscience 336 (2004). 相似文献
20.
《Quaternary Science Reviews》2007,26(11-12):1621-1637
A review of Holocene climate patterns in eastern Australia is presented on the basis of a series of high-resolution pollen records across a north-to-south transect. Previously published radiocarbon data are calibrated into calendar years and fitted with an age-depth model. The resulting chronologies are used to compare past environmental changes and describe patterns of climate change on a calendar-age scale. Based on the present-day Australian climate patterns and impact of the El Niño-Southern Oscillation (ENSO), the palynological data are interpreted and the prevalent climate mode throughout the Holocene reconstructed. Results show that early Holocene changes are strongly divergent and asynchronous between sites, while middle to late Holocene conditions are characterized by more arid and variable conditions and greater coupling between northern and southern sites, which is in agreement with increasing influence of ENSO. 相似文献