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1.
This paper is proposed for the investigation of possible relationships between the large-scale atmospheric circulation phenomena such as the North Atlantic Oscillation (NAO), Southern Oscillation (SOI), Mediterranean Oscillation (MO), Western Mediterranean Oscillation (WeMO) and rainfall of Sebaou river watershed (Northern central Algeria), covering a period of 39 years at monthly scale. Several time and scale-based methods were used: correlation and spectral analysis (CSA), continuous wavelet transform (CWT), multiresolution wavelet analysis (MRWA), cross wavelet analysis (XWT), wavelet coherence transform (WCT) and cross multiresolution wavelet analysis (CMRWA). The rainfall analysis by CSA and CWT has been clearly demonstrating the dominance of 1 year and 1–3-year modes, which they explain 30 to 51% and 25 to 28% of the variance respectively. However, the indices have shown that inter-annual fluctuations up to long-term explain between 60 and 90%. CWT and MRWA indicated significant fluctuations materialising a dry period more marked between the 1980s and 1990s with strong trend towards drier conditions starting from the 1980s, explained by the decadal components D7 and the approximation A7. In addition to the annual component, the XWT spectrums reveal strong coefficients for the SOI between 1992–2005 and 1986–2000 for the modes of 5–10 years and higher than 10 years respectively and less intense for NAO. The WCT between NAO and rainfall indicated the most significant relationship for 1 year, 1–3 years and 3–5 years approximately from the early 1980s corresponding to the dry period. However, the SOI affects rainfall only locally and with significant values more or less localised in the time-frequency space between MO, WeMO and rainfall, but this influence could be significant for low-frequency events. CWMRA shows that the components of 5–10 years and higher than 10 years are the most effective to represent climate index-rainfall significant relationships, where change in Daubechies wavelet properties can improve the correlation across the scales. Furthermore, has indicated that the short-term processes dominate the relationship index-rainfall, which masks the long-term phenomena whose influence can sometimes be very distant. As such, the rainfall variability of the study area has shown fairly significant links, at least locally with large-scale atmospheric circulation phenomena.  相似文献   

2.
Eighty-two-year rainfall time series have been studied together with climatic patterns of NAO using classical statistical methods. Then, the wavelet approach has been applied to show annual (1 year (1y)) and inter-annual (2–4 years (2-4y), 5–8 years (5-8y), and 8–16 years (8-16y)) modes distributed following four major discontinuities: 1945, 1960, 1975, and 1995. The 1y, 2-4y, and 5-8y powers show high energy during the wet period 1922–1930 and a low one in 1928–1938. After 1945, the annual mode highlights a high energy while the inter-annual modes present low energy. Between 1975 and 1995, powerful modes of 1 and 2–4 years are identified with low power of 5-8y and 8-16y modes. Since 1995, the low power of 5–8y decreases, while the 8-16y mode emphasizes a high variability. The coherence between NAO and Marrakech precipitation is strongly defined for low frequencies with a total contribution of 75 %. This coherence is in phase in the beginning and presents out phase signs since 1945. The change of phase can be associated to a decreasing of coherence especially around 1990. This finding is useful to understand the relationship between the hydrological variability and NAO climate patterns in the southern side of the Mediterranean Sea.  相似文献   

3.
Shared nearest neighbour (SNN) cluster algorithm has been applied to seasonal (June–September) rainfall departures over 30 sub-divisions of India to identify the contiguous homogeneous cluster regions over India. Five cluster regions are identified. Rainfall departure series for these cluster regions are prepared by area weighted average rainfall departures over respective sub-divisions in each cluster. The interannual and decadal variability in rainfall departures over five cluster regions is discussed. In order to consider the combined effect of North Atlantic Oscillation (NAO) and Southern Oscillation (SO), an index called effective strength index (ESI) has been defined. It has been observed that the circulation is drastically different in positive and negative phases of ESI-tendency from January to April. Hence, for each phase of ESI-tendency (positive and negative), separate prediction models have been developed for predicting summer monsoon rainfall over identified clusters. The performance of these models have been tested and found to be encouraging.  相似文献   

4.
This paper presents an overview of storminess along the Danube delta coast since 1949 by analysing wind and wave data and discusses the influences of teleconnections on climate variability. To this end, a five-category storm classification is proposed based on wind speed intensity and storm duration. On average, this coast experiences 30 storms/year occurring predominantly in winter, three of them considered severe (categories III–IV). The extreme storms (cat. V) endanger most the coastal settlements and the back-beach ecosystems (sand dunes, wetlands, lagoons) and have a mean recurrence rate of 7 years, but occur with a large inter-annual variability more frequent during the late 1960s, the 1970s and the 1990s. The prevalence of northern storms, in particular for the severe ones (>90% frequency for wind speeds >20 m/s) is responsible for the vigorous southward longshore sediment transport, which shaped the Danube delta physiognomy over the last millennia. The application of the newly developed energetic (Storm Severity Index—SSI) and morphologic (Storm Impact Potential—SIP) proxies allowed the better assessment of both the storm strength and the temporal variation in storm energy. It appears that storm climate follows a cyclic pattern with successive periods of 7–9 years of high, moderate and low storminess in accordance with the main teleconnections patterns (North Atlantic Oscillation—NAO, East Atlantic oscillation—EA, East Atlantic/Western Russia—EAWR, Scandinavian oscillation—SCAND). If NAO succeeded to explain best most of the storminess evolution (r = ?0.76 for 1962–2005), it failed during the latest decade (since 2006) when an unprecedented low in storminess occurred. There is also evidence of increased southern circulation during the latter period, associated with a reversal of correlation with NAO (from negative to positive). Significant correlations were also found for the EA, EAWR and SCAND (r = ?0.55, 0.56, 0.55, respectively, significant at p < 0.01) for all the study period suggesting that besides NAO, the north-western Black Sea coast storminess is considerably influenced by several modes of climate variability, most notable the EA and the EAWR, which succeed to address the recent decrease in storminess.  相似文献   

5.
This study examines spatial and temporal variability of rainfall in Bizerte-Ichkeul Watershed. The basin, located in the extreme north of Tunisia, covers an area of 3084 km2. Thirteen rainfall stations, with continuous monthly precipitation records over the period (1970–2011), were considered in the analysis. Two methods were used. In the first, the dimensionless standardized precipitation ratio is applied to examine precipitation temporal variation. The second method is represented by continuous wavelet analysis for the precipitation spatial analysis and the identification of the origin of its variability. The study of temporal variability of annual rainfall showed severe persistent and recurrent drought episodes over the period (1977–2001). Wavelet analysis resulted in detecting the modes and origins of precipitation variability. Three energy bands were clearly identified: (1, 2–4, and 4–8 years) for the entire watershed. The visualization of the power distribution showed that the observed modes of variability are different in their power distributions from one station to another. The approach adopted allowed the identification of two groups with the same precipitation frequency and temporal variation. These groups were defined according to the difference in occurrence of the frequency band for each station.  相似文献   

6.
Observed summer (May–October) rainfall in Myanmar for the period 1981–2010 was used to investigate the interannual variability of summer monsoon rainfall over Myanmar. Empirical orthogonal function, the sequential Mann-Kendall test, power spectrum analysis, and singular value decomposition (SVD) were deployed in the study. Results from spectral analysis showed that the variability of rainfall over Myanmar exhibits a 2- to 6-year cycle. An abrupt change in rainfall over the country was noted in 1992. There was a notable increasing rainfall trend from 1989. After the sudden change, the mean rainfall increased by 36.1 mm, compared with the mean rainfall before the sudden change, and was associated with a rise in temperature of about 0.2 °C. An increase in heavy rainfall days was observed from the early 1990s to 2010. IOD and ENSO play an important role in the interannual variability of the summer rainfall over Myanmar. The covariability between rainfall over Myanmar and Indian Ocean SST generally suggests that a positive IOD mode is associated with suppressed rainfall in the central and northern parts of Myanmar. During a negative IOD mode, nearly the whole Myanmar experiences enhanced rainfall, which is associated with devastating socioeconomic impacts. The covariability between the rainfall over Myanmar and the sea surface temperature in the Pacific Ocean in the first and second SVD modes was dominated by warming in the east and central Pacific—an El Niño-like pattern—resulting in dry conditions in central Myanmar.  相似文献   

7.
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   

8.
To investigate environmental variability during the late Holocene in the western Gulf of Maine, USA, we collected a 142-year-old living bivalve (Arctica islandica) in 2004, and three fossil A. islandica shells of the Medieval Warm Period (MWP) and late MWP / Little Ice Age (LIA) period (corrected 14CAMS = 1030 ± 78 ad; 1320 ± 45 ad; 1357 ± 40 ad) in 1996. We compared the growth record of the modern shell with continuous plankton recorder (CPR) time-series (1961–2003) from the Gulf of Maine. A significant correlation (r 2 = 0.55; p < 0.0001) exists between the standardized annual growth index (SGI) of the modern shell and the relative abundance of zooplankton species Calanus finmarchicus. We therefore propose that SGI data from A. islandica is a valid proxy for paleo-productivity of at least one major zooplankton taxa. SGIs from these shells reveal significant periods of 2–6 years (NAO-like) based on wavelet analysis, multitaper method (MTM) analysis and singular spectrum analysis (SSA) during the late Holocene. Based on established physical oceanographic observation in the Gulf of Maine, we suggest that slope water variability coupled with North Atlantic Oscillation (NAO) dynamics is primarily responsible for the observed SGI variability. Special Issue: AGU OS06 special issue “Ocean’s role in climate change—a paleo perspective”.  相似文献   

9.
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   

10.
The aim of this study was to investigate temporal variation in seasonal and annual rainfall trend over Ranchi district of Jharkhand, India for the period (1901–2014: 113 years). Mean monthly rainfall data series were used to determine the significance and magnitude of the trend using non-parametric Mann–Kendall and Sen’s slope estimator. The analysis showed a significant decreased in rainfall during annual, winter and southwest monsoon rainfall while increased in pre-monsoon and post-monsoon rainfall over the Ranchi district. A positive trend is detected in pre-monsoon and post-monsoon rainfall data series while annual, winter and southwest monsoon rainfall showed a negative trend. The maximum decrease in rainfall was found for monsoon (? 1.348 mm year?1) and minimum (? 0.098 mm year?1) during winter rainfall. The trend of post-monsoon rainfall was found upward (0.068 mm year?1). The positive and negative trends of annual and seasonal rainfall were found statistically non-significant except monsoon rainfall at 5% level of significance. Rainfall variability pattern was calculated using coefficient of variation CV, %. Post-monsoon rainfall showed the maximum value of CV (70.80%), whereas annual rainfall exhibited the minimum value of CV (17.09%), respectively. In general, high variation of CV was found which showed that the entire region is very vulnerable to droughts and floods.  相似文献   

11.
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   

12.
Blooms of Aureococcus anophagefferens in Chincoteague Bay were observed during 5 of 6 years between 2002 and 2007. In order to understand factors controlling blooms, interannual differences in nitrogen and carbon uptake and concentrations of dissolved constituents were compared at two sites in Chincoteague Bay, MD and VA over the 6-year time period. Over that time, we observed that there was no single nitrogen compound that fueled blooms each year. Instead, A. anophagefferens took up a wide range of nitrogen compounds to meet its nutritional demands. Although photosynthetic carbon fixation was the dominant form of carbon acquisition during blooms, organic carbon uptake contributed up to 30 % of the total carbon uptake. In addition to interannual variability in nitrogen and carbon uptake, we observed that there was an increase in bloom intensity and duration over the 6-year study period during which dissolved organic carbon appeared to accumulate in the system.  相似文献   

13.
The majority of landsliding episodes in the area north of Lisbon are associated with rainfall events of short (less than 5 days) medium (5–20 days) or long duration (more than 20 days). The precipitation regime in Portugal is highly irregular, with large differences between wet and dry years. We have assessed the impact of the North Atlantic Oscillation (NAO) on both the winter precipitation and the timing and magnitude of associated landslide events. Results show that the large inter-annual variability of winter precipitation is largely modulated by the NAO mode. The precipitation composite corresponding to high NAO index presents a considerable lower median value (47 mm/month) than the corresponding low NAO index class (134 mm/month). The entire precipitation distribution associated with the low NAO index composite encompasses a wider range of values than the corresponding high NAO index composite. This non-linear behavior is reflected in the probability of occurrence of a very wet month (precipitation above the 90% percentile) that is just 1% for the positive NAO class and 23% for low NAO index months. Results for the low NAO class are crucial because these months are more likely associated with long-lasting rainfall episodes responsible for large landslide events. This is confirmed by the application of a 3-month moving average to both NAO index and precipitation time series. This procedure allowed the identification of many months with landslide activity as being characterized by negative average values of the NAO index and high values of average precipitation (above 100 mm/month). Finally, using daily data we have computed the return periods associated with the entire set of landslide episodes and, based on these results, obtained a strong linear relationship between critical cumulative rainfall and the corresponding critical rainfall event duration.  相似文献   

14.
The northeast monsoon rainfall (NEMR) contributes about 20–40 % of annual rainfall over the North Indian Ocean (NIO). In the present study, the relationship between the NEMR and near-surface atmospheric wind convergence (NSAWC) over the NIO is demonstrated using high-resolution multisatellite data. The rainfall product from the Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis and near-surface wind product from the Cross-Calibration Multi-Platform available at 0.25° × 0.25° spatial resolution are used for the study. Large-scale NSAWC and divergence maps over the tropical Indian Ocean are generated at monthly scale from the wind product for the period of 1988–2010. A preliminary analysis is carried out for two consecutive anomalous Indian Ocean Dipole (IOD) years 2005 (negative) and 2006 (positive). The distinct spatial patterns of rainfall rate and NSAWC fields over the NIO clearly show the evolution of the anomalous IOD events in the south eastern equatorial Indian Ocean (EEIO). The spatially averaged time-series of pentad NSAWC over the south EEIO box suggests that the variability occurs in phase with rainfall rate during both the northeast monsoon years. Furthermore, the scatter plot between area-averaged pentad rainfall and convergence over the south EEIO box for the period of 1998–2010 shows statistically significant linear correlation which reveals that NSAWC plays a key role in regulating the NEMR.  相似文献   

15.
Rainfall is one of the pivotal climatic variables, which influence spatio-temporal patterns of water availability. In this study, we have attempted to understand the interannual long-term trend analysis of the daily rainfall events of ≥?2.5 mm and rainfall events of extreme threshold, over the Western Ghats and coastal region of Karnataka. High spatial resolution (0.25°?×?0.25°) daily gridded rainfall data set of Indian Meteorological Department was used for this study. Thirty-eight grid points in the study area was selected to analyze the daily precipitation for 113 years (1901–2013). Grid points were divided into two zones: low land (exposed to the sea and low elevated area/coastal region) and high land (interior from the sea and high elevated area/Western Ghats). The indices were selected from the list of climate change indices recommended by ETCCDI and are based on annual rainfall total (RR), yearly 1-day maximum rainfall, consecutive wet days (≥?2.5 mm), Simple Daily Intensity Index (SDII), annual frequency of very heavy rainfall (≥?100 mm), frequency of very heavy rainfall (≥?65–100 mm), moderate rainfall (≥?2.5–65 mm), frequency of medium rainfall (≥?40–65 mm), and frequency of low rainfall (≥?20–40 mm). Mann-Kendall test was applied to the nine rainfall indices, and Theil-Sen estimator perceived the nature and the magnitude of slope in rainfall indices. The results show contrasting trends in the extreme rainfall indices in low land and high land regions. The changes in daily rainfall events in the low land region primarily indicate statistically significant positive trends in the annual total rainfall, yearly 1-day maximum rainfall, SDII, frequency of very heavy rainfall, and heavy rainfall as well as medium rainfall events. Furthermore, the overall annual rainfall strongly correlated with all the rainfall indices in both regions, especially with indices that represent heavy rainfall events which is responsible for the total increase of rainfall.  相似文献   

16.
The discovery of decadal variability of North Atlantic Oscillation (NAO) and the introduction of Arctic oscillation (AO) concept have initiated a series of paleo-AO/NAO related studies since the mid-to-late 1990s. The progress and new findings of paleo-AO/NAO works after that time were comprehensively reviewed. The new results from the observations and modelings at four key timescales were summarized in detail: ①the reconstructions of the AO/NAO annual index over the past millennium; ②the debate on AO/NAO’s trend since early Holocene; ③the weakening of AO/NAO’s amplitude during the Last Glacial Maximum; and ④the anomalous positive phase of AO/NAO during the Last Interglacial. In addition, the possible mechanism for different timescales of AO/NAO is also summarized. Furthermore, the distinction between AO/NAO’ was mean state and amplitude, which were not explicitly separated in previous studies, were comprehensively discussed. Considering the current uncertainties related to paleo-AO/NAO studies, we encourage the community to search for more proxies having longer-than-10,000-year length with annual resolution around AO/NAO highly correlated regions. Another, we encourage long-term transient modeling on AO/NAO can be performed in order to improve our understanding of the dynamics and interaction between AO/NAO’s high-frequency variability and the climatological background, so as to further improve AO/NAO’s predictability on global warming context.  相似文献   

17.
Research on vegetation change, rangeland assessment or desertification modelling in drylands using remotely sensed image acquisition normally ignores long-term rainfall as a key criterion in image acquisition. This article will present a novel procedure for image acquisition to investigate vegetation change in a degraded rangeland located in Western New South Wales (Western NSW) Australia. Western NSW experienced an unusually prolonged period of rainfall deficit during the 2000s compared to the 1970, 1980 and 1990s. For this purpose, vegetation changes were assessed using Landsat images supported by field survey. The long-term rainfall variability (42-year) was regarded as a key element in image acquisition. Within the timeframe of the 2000s, 2 years with 25 % lower than the 42-year mean annual rainfall were selected. These images were then compared to an image captured in a year (1988) with rainfall closer to the 42-year mean annual rainfall. Two change detection techniques were used, namely univariate image differencing and GIS approaches. Classification of the produced images was pursued based on the digital numbers (supervised) of ground-checked points within the reference image whilst considering the histogram (unsupervised) of each digital number of the produced image. This research emphasized rainfall as a key variable in image acquisition for vegetation change analysis in rangelands. Image acquisition based on long-term rainfall data allowed for the assessment of changes in perennial plant cover by eliminating the effects of extreme rainfall variation on annual grass dynamics and removing extreme reflections caused by their temporary high photosynthetic activity.  相似文献   

18.
Having recognized that it is the tropospheric temperature (TT) gradient rather than the land–ocean surface temperature gradient that drives the Indian monsoon, a new mechanism of El Niño/Southern Oscillation (ENSO) monsoon teleconnection has been unveiled in which the ENSO influences the Indian monsoon by modifying the TT gradient over the region. Here we show that equatorial Pacific coralline oxygen isotopes reflect TT gradient variability over the Indian monsoon region and are strongly correlated to monsoon precipitation as well as to the length of the rainy season. Using these relationships we have been able to reconstruct past Indian monsoon rainfall variability of the first half of the 20th century in agreement with the instrumental record. Additionally, an older coral oxygen isotope record has been used to reconstruct seasonally resolved summer monsoon rainfall variability of the latter half of the 17th century, indicating that the average annual rainfall during this period was similar to that during the 20th century. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

19.
Large-scale, low frequency modes such as the North Atlantic Oscillation(NAO)and blocking, have an important modulation on the northern hemisphere weather and climate. In this paper, the physical mechanism studies on inter-decadal and decadal variability of NAO and blocking were summarized. The relationship between NAO regime transitions and the interannual variability of NAO in winter during was examined by using a statistical approach. The time-space relationship between NAO and European blocking were discussed. Based on two extreme cold and snowstorm events, the impacts on local weather especially the extreme events within the life cycle (two weeks) of the NAO and blocking were further examined. It was found that the frequently occurrence of the Eurasian extreme snowstorm was closely related to the special combination of NAO and blocking regime. In addition, the development of theoretical modes for NAO and blocking was discussed and issues that remain to be solved were proposed.  相似文献   

20.
The wavelet transform was applied to studying the regime shifts of hydrometeorological factors(i.e.,precipitation,air temperature,sea surface temperature and sea surface salinity)during the period of 1961–2000 in the Jiaozhou Bay(JZB).The results indicated clearly that these factors show variability of multiple timescales,with interannual and decadal periods.The local abrupt changes such as the 1978–1979 and 1988–1989 shifts feature the physical environment variation,which is consistent with the Southern Oscillation and Arctic Oscillation in the northern hemisphere.In regard to the JZB ecosystem,the benthic diatom cell abundance(BEN)showed a decrease shift in1978–1979,which is closely related to the precipitation abrupt decrease,while the shellfish mortality disaster in the JZB greatly released the predating pressure of diatom growth,possibly resulting in BEN increase shift in 1995.  相似文献   

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