scholarly journals Is the Water Temperature of the Danube River at Bratislava, Slovakia, Rising?

2008 ◽  
Vol 9 (5) ◽  
pp. 1115-1122 ◽  
Author(s):  
Pavla Pekarova ◽  
Dana Halmova ◽  
Pavol Miklanek ◽  
Milan Onderka ◽  
Jan Pekar ◽  
...  
Keyword(s):  
Time Series ◽  
Water Temperature ◽  
Heat Load ◽  
Empirical Relationship ◽  
Danube River ◽  
Average Heat ◽  
The Danube River ◽  
Average Temperature ◽  
Monthly Discharge

Abstract This paper aims to reveal the annual regime, time series, and long-term water temperature trends of the Danube River at Bratislava, Slovakia, between the years 1926 and 2005. First, the main factors affecting the river’s water temperature were identified. Using multiple regression techniques, an empirical relationship is derived between monthly water temperatures and monthly atmospheric temperatures at Vienna (Hohe Warte), Austria, monthly discharge of the Danube, and some other factors as well. In the second part of the study, the long-term trends in the annual time series of water temperature were identified. The following series were evaluated: 1) The average annual water temperature (To) (determined as an arithmetic average of daily temperatures in the Danube at Bratislava), 2) the weighted annual average temperature values (Toυ) (determined from the daily temperatures weighted by the daily discharge rates at Bratislava), and 3) the average heat load (Zt) at the Bratislava station. In the long run, the To series is rising; however, the trend of the weighted long-term average temperature values, Toυ, is near zero. This result indicates that the average heat load of the Danube water did not change during the selected period of 80 yr. What did change is the interannual distribution of the average monthly discharge. Over the past 25 yr, an elevated runoff of “cold” water (increase of the December–April runoff) and a lower runoff of “warm” water (decrease of the river runoff during the summer months of June–August) were observed.

scholarly journals Long-Term Runoff Variability Analysis of Rivers in the Danube Basin

2021 ◽  
Vol 24 (s1) ◽  
pp. 37-44
Author(s):  
Pavla Pekárová ◽  
Jakub Mészáros ◽  
Pavol Miklánek ◽  
Ján Pekár ◽  
Stevan Prohaska ◽  
...  
Keyword(s):  
Time Series ◽  
River Basin ◽  
Danube River ◽  
Data Series ◽  
Discharge Time ◽  
The Danube River ◽  
Runoff Variability ◽  
Annual Discharge ◽  
Danube River Basin

Abstract The long-term runoff variability is identified to consist of the selected large rivers with long-term data series in the Danube River Basin. The rivers were selected in different regions of the Danube River Basin and have a large basin area (Danube: Bratislava gauge with 131,338 km2; Tisza: Senta with 141,715 km2; and Sava: Sremska Mitrovica with 87,966 km2). We worked with the station Danube: Reni in the delta as well. A spectral analysis was used to identify the long-term variability of three different types of time series: (1) Average annual discharge time series, (2) Minimum annual discharge time series and (3) Maximum annual discharge time series. The results of the study can be used in a long-term forecast of the runoff regime in the future.

scholarly journals Prediction of Water Quality in the Danube River Under extreme Hydrological and Temperature Conditions

2009 ◽  
Vol 57 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Pavla Pekárová ◽  
Milan Onderka ◽  
Ján Pekár ◽  
Peter Rončák ◽  
Pavol Miklánek
Keyword(s):  
Water Quality ◽  
Water Resources ◽  
Water Temperature ◽  
Danube River ◽  
The Danube River ◽  
Temperature Conditions ◽  
Water Quality Variables ◽  
Time Flow ◽  
The Impact

Prediction of Water Quality in the Danube River Under extreme Hydrological and Temperature ConditionsOne of the requirements imposed by the Water Framework Directive (WFD, 2000/60/EC) is to analyze and predict how quality of surface waters will evolve in the future. In assessing the development of a stream's pollution one must consider all sources of pollution and understand how water quality evolves over time. Flow and water temperature regime of a stream or river are the main factors controlling the extent to which deterioration of a stream's water quality can propagate under constant input from pollution sources. In addition, there is ever increasing public concern about the state of the aquatic environment. Decision makers and scientists involved in water management call for studies proposing simulation models of water quality under extreme natural hydrologic and climatic scenarios. Also, human impact on water resources remain an issue for discussion, especially when it comes to sustainability of water resources with respect to water quality and ecosystem health. In the present study we investigate the long-term trends in water quality variables of the Danube River at Bratislava, Slovakia (Chl-a, Ca, EC, SO2-, Cl-, O2, BOD5, N-tot, PO4-P, NO3-N, NO2-N, etc.), for the period 1991-2005. Several SARIMA models were tested for the long-term prediction of selected pollutant concentrations under various flow and water temperature conditions. In order to create scenarios of selected water quality variables with prediction for 12 months ahead, three types of possible hydrologic and water temperature conditions were defined: i) average conditions - median flows and water temperature; ii) low flows and high water temperature; and iii) high flows and low water temperature. These conditions were derived for each month using daily observations of water temperature and daily discharge readings taken in the Danube at Bratislava over the period 1931-2005 in the form of percentiles (1th-percentile, median, 99th-percentile). Once having derived these extreme-case scenarios, we used selected Box-Jenkins models (with two regressors - discharge and water temperature) to simulate the extreme monthly water quality variables. The impact of natural and man-made changes in a stream's hydrology on water quality can be readily well simulated by means of autoregressive models.

scholarly journals Functional diversity of phytoplankton highlights long-term gradual regime shift in the middle section of the Danube River due to global warming, human impacts and oligotrophication

2018 ◽  
Vol 63 (5) ◽  
pp. 456-472 ◽  
Author(s):  
András Abonyi ◽  
Éva Ács ◽  
András Hidas ◽  
István Grigorszky ◽  
Gábor Várbíró ◽  
...  
Keyword(s):  
Global Warming ◽  
Functional Diversity ◽  
Regime Shift ◽  
Human Impacts ◽  
Danube River ◽  
Middle Section ◽  
The Danube River

scholarly journals Metabarcoding Reveals Temporal Patterns of Community Composition and Realized Thermal Niches of Thalassiosira Spp. (Bacillariophyceae) from the Narragansett Bay Long-Term Plankton Time Series

Biology ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 19 ◽  
Author(s):  
Tatiana A. Rynearson ◽  
Sarah A. Flickinger ◽  
Diana N. Fontaine
Keyword(s):  
Time Series ◽  
Surface Water ◽  
Light Microscopy ◽  
Water Temperature ◽  
Dna Sequences ◽  
Cold Water ◽  
Narragansett Bay ◽  
Historical Records ◽  
Surface Water Temperature

Diatoms generate nearly half of marine primary production and are comprised of a diverse array of species that are often morphologically cryptic or difficult to identify using light microscopy. Here, species composition and realized thermal niches of species in the diatom genus Thalassiosira were examined at the site of the Narragansett Bay (NBay) Long-Term Plankton Time Series using a combination of light microscopy (LM), high-throughput sequencing (HTS) of the 18S rDNA V4 region and historical records. Thalassiosira species were identified over 6 years using a combination of LM and DNA sequences. Sixteen Thalassiosira taxa were identified using HTS: nine were newly identified in NBay. Several newly identified species have small cell diameters and are difficult to identify using LM. However, they appeared frequently and thus may play a significant ecological role in NBay, particularly since their realized niches suggest they are eurythermal and able to tolerate the >25 °C temperature range of NBay. Four distinct species assemblages that grouped by season were best explained by surface water temperature. When compared to historical records, we found that the cold-water species Thalassiosira nordenskioeldii has decreased in persistence over time, suggesting that increasing surface water temperature has influenced the ecology of phytoplankton in NBay.

Changes in the Quality of the Danube River Water in the Section Smederevo-Kladovo in the Conditions of Backwater Effects

1990 ◽  
Vol 22 (5) ◽  
pp. 181-188 ◽  
Author(s):  
M. Peršić ◽  
M. Miloradov ◽  
V. Tutundžić ◽  
Z. Čukić
Keyword(s):  
River Water ◽  
Danube River ◽  
Hydropower Plant ◽  
Biochemical Processes ◽  
The Danube River ◽  
Global View ◽  
Physico Chemical ◽  
Composition And Structure

The paper describes specific changes in the quality of the Danube river water under the conditions of backwater effects in the Hydropower Plant Djerdap I storage. The results of longterm tests in five profiles of the investigated section, at various discharges give a global view of the intensity of changes in the composition of water mass. The analysis included changes in the contents of: organic matter, oxygen regime, reduction of turbidity and changes in the composition and abundance of plankton. The specific changes in the domain of physico-chemical and biochemical processes and changes in the biological status of the watercourse (composition and structure of plankton) at varying retention times complete the picture of short-term changes in the investigated system. Presentation of some settling effects and processes in the sediment of the storage provides an idea of some long-term changes in the conditions of backwater effects of the Danube in the investigated section.

scholarly journals Time Series Decomposition of the Daily Outdoor Air Temperature in Europe for Long-Term Energy Forecasting in the Context of Climate Change

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1569
Author(s):  
Santiago Moreno-Carbonell ◽  
Eugenio F. Sánchez-Úbeda ◽  
Antonio Muñoz
Keyword(s):  
Time Series ◽  
Outdoor Air ◽  
Annual Average ◽  
Energy Forecasting ◽  
Average Temperature ◽  
Time Series Decomposition ◽  
Temperature Forecasting ◽  
Term Energy ◽  
Annual Average Temperature

Temperature is widely known as one of the most important drivers to forecast electricity and gas variables, such as the load. Because of that reason, temperature forecasting is and has been for years of great interest for energy forecasters and several approaches and methods have been published. However, these methods usually do not consider temperature trend, which causes important error increases when dealing with medium- or long-term estimations. This paper presents several temperature forecasting methods based on time series decomposition and analyzes their results and the trends of 37 different European countries, proving their annual average temperature increase and their different behaviors regarding trend and seasonal components.

An in situ Evaluation of the Day-to-Day Variation in the Quantity of Food Consumed by Fish

1993 ◽  
Vol 50 (10) ◽  
pp. 2157-2165 ◽  
Author(s):  
Marc Trudel ◽  
Daniel Boisclair
Keyword(s):  
Time Series ◽  
Water Temperature ◽  
Food Consumption ◽  
Daily Ration ◽  
Consumption Rates ◽  
Sampling Intervals ◽  
The Mean ◽  
Food Consumed

We tested the hypothesis that the mean quantity food consumed by fish in situ does not vary significantly over successive days. The daily ration of minnows (Phoxinus eos × P. neogaeus) was estimated over 5–12 consecutive days (June 1–5, July 6–17, and August 3–9, 1992). Mean daily ration ranged from 0.60 to 1.32 g dry∙100 g wet−1∙d−1 and varied significantly over consecutive days in June and July, but not in August. Average day-to-day variation in food consumption rates ranged from 7.0 to 16.3%. Mean daily ration was not influenced by either water temperature or percent cloudiness. Simulated long-term consumption rates of minnows did not vary by more than 19.3% among sampling intervals ranging from 1 to 30 d. We conclude that long-term consumption rates can be accurately determined using time series of daily ration estimated at 3- to 4-wk intervals.

Long-term monitoring of the Danube river—Sampling techniques, radionuclide metrology and radioecological assessment

2009 ◽  
Vol 67 (5) ◽  
pp. 894-900 ◽  
Author(s):  
F.J. Maringer ◽  
V. Gruber ◽  
M. Hrachowitz ◽  
A. Baumgartner ◽  
S. Weilner ◽  
...  
Keyword(s):  
Danube River ◽  
Sampling Techniques ◽  
The Danube River ◽  
Long Term Monitoring ◽  
Radionuclide Metrology ◽  
Term Monitoring
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