scholarly journals Long-term Changes of Water Level Associated with Chlorophyll a Concentration in Lake Baiyangdian, North China

2012 ◽  
Vol 13 ◽  
pp. 1227-1237 ◽  
Author(s):  
Fei Wang ◽  
Xuan Wang ◽  
Ying Zhao ◽  
Zhifeng Yang
Keyword(s):  
Water Level ◽  
Chlorophyll A ◽  
North China ◽  
Chlorophyll A Concentration ◽  
Long Term Changes ◽  
Lake Baiyangdian

Environmental factors associated with long-term changes in chlorophyll-<b><i>a</i></b> concentration in the Amazon floodplain

2011 ◽  
Vol 8 (2) ◽  
pp. 3739-3770 ◽  
Author(s):  
E. Alcântara ◽  
E. M. Novo ◽  
C. F. Barbosa ◽  
M.-P. Bonnet ◽  
J. Stech ◽  
...  
Keyword(s):  
Time Series ◽  
Power Spectrum ◽  
Water Level ◽  
Chlorophyll A ◽  
Wave Radiation ◽  
Significant Variable ◽  
Chlorophyll A Concentration ◽  
Time Frequency ◽  
The Relationship

Abstract. Long-term environmental time series of continuously collected data are fundamental to identify and classify pulses and determine their role in aquatic systems. This paper presents in situ daily mean chlorophyll-a concentration time series, key information for the current understanding of carbon fluxes in and out of the Amazonian floodplain system. This paper also investigates how seasonal fluctuations in water level affect the relationship between chlorophyll-a concentration and some of its controlling limnological (water level, water surface temperature, pH and turbidity) and meteorological (wind intensity, relative humidity and short wave radiation) variables provided by an automatic monitoring system (Integrated System for Environmental Monitoring-SIMA) deployed at Curai Lake. The data are collected in preprogrammed time interval (1 h) and are transmitted by satellite in quasi-real time for any user in a range of 2500 km from the acquisition point. We used Pearson correlation to determine the quantitative relationship between chlorophyll-a time series and others environmental parameters. Fourier power spectrum analyses were applied to identify periods of high variability in chlorophyll-a time series and wavelet power spectrum analyses helped to characterize their time-frequency structure. To further investigate the relationship between chlorophyll-a and the statistically significant variable highlighted by Pearson's correlation, the set of time series was submitted to cross wavelet analysis. The time series of chlorophyll-a shows two high peaks (47 μg L−1 and 53.30 μg L−1) of concentration during a year: first during the rising water and second during the low water level. A small peak was observed during the high water level (10 μg L−1). For the most part of rising, high and receding water level, the chlorophyll-a concentration is often low (from 2.20 μg L−1 to 9.10 μg L−1). chlorophyll-a concentration displays periodicities ranging from 2–60 days, with a coherence of approximately 1 in phase with water level during the rising and low water period. Water level dynamics and turbidity explain 68% of the chlorophyll-a time series variability.

Sedimentary Cladocera as indicators of past water-level changes in shallow northern lakes

2011 ◽  
Vol 75 (3) ◽  
pp. 430-437 ◽  
Author(s):  
Liisa Nevalainen ◽  
Kaarina Sarmaja-Korjonen ◽  
Tomi P. Luoto
Keyword(s):  
Water Level ◽  
Lake Level ◽  
Water Levels ◽  
Sediment Record ◽  
Inference Model ◽  
Water Level Changes ◽  
Long Term Changes ◽  
Lower Water Level ◽  
The Relationship

AbstractThe usability of subfossil Cladocera assemblages in reconstructing long-term changes in lake level was examined by testing the relationship between Cladocera-based planktonic/littoral (P/L) ratio and water-level inference model in a surface-sediment dataset and in a 2000-yr sediment record in Finland. The relationships between measured and inferred water levels and P/L ratios were significant in the dataset, implying that littoral taxa are primarily deposited in shallow littoral areas, while planktonic cladocerans accumulate abundantly mainly in deepwater locations. The 2000-yr water-level reconstructions based on the water-level inference model and P/L ratio corresponded closely with each other and with a previously available midge-inferred water-level reconstruction from the same core, showing a period of lower water level around AD 300–1000 and suggesting that the methods are valid for paleolimnological and -climatological use.

scholarly journals 14th-16th-Century Danube Floods and Long-Term Water-Level Changes in Archaeological and Sedimentary Evidence in The Western and Central Carpathian Basin: an Overview with Documentary Comparison

2013 ◽  
Vol 6 (3-4) ◽  
pp. 1-11 ◽  
Author(s):  
Andrea Kiss ◽  
József Laszlovszky
Keyword(s):  
Water Level ◽  
Carpathian Basin ◽  
Building Structures ◽  
Flood Events ◽  
Water Level Changes ◽  
Present Information ◽  
Long Term Changes ◽  
Average Water ◽  
Morphological Processes

Abstract In the present paper an overview of published and unpublished results of archaeological and sedimentary investigations, predominantly reflect on 14th-16th-century changes, are provided and evidence compared to documentary information on flood events and long-term changes. Long-term changes in flood behaviour (e.g. frequency, intensity, seasonality) and average water-level conditions had long-term detectable impacts on sedimentation and fluvio-morphological processes. Moreover, the available archaeological evidence might also provide information on the reaction of the society, in the form of changes in settlement organisation, building structures and processes. At present, information is mainly available concerning the 16th, and partly to the 14th-15th centuries. These results were compared to the available documentary evidence on 14th-16th century Danube floods occurred in the Carpathian Basin.

scholarly journals Hydrological Regime of the Trans-Baikal Lakes in the conditions of the Changing Climate (Ivano-Arakhleysky Lakes as a Study Case)

2011 ◽  
pp. 4-14
Author(s):  
Keyword(s):  
Water Level ◽  
Climate Changes ◽  
Atmospheric Precipitation ◽  
Hydrological Regime ◽  
Water Level Fluctuations ◽  
Changing Climate ◽  
Long Term Changes ◽  
Study Case ◽  
Ice Water

Long-term changes of temperature of air and atmospheric precipitation in Transbaikalia and their influence on the hydrological regime of the Ivano-Arahleysky lakes are considered in the article. Climate changes have caused rise in temperature of water of lakes, reduction a thickness of ice and duration of standing of ice. Water level fluctuations have cyclic character and depend on long-term changes of atmospheric precipitation.

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