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Wyszukujesz frazę "mann-kendall test" wg kryterium: Temat


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Tytuł:
Trend analysis of flood peaks in lower reaches of Satluj River, Himachal Pradesh, India
Autorzy:
Kumar, S.
Santosh, ---
Powiązania:
https://bibliotekanauki.pl/articles/970628.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
flood peaks
mann-kendall test
satluj river basin
regression
trend analysis.
Opis:
Climate change arising from anthropogenic driven emissions of greenhouse gases has emerged as one of the most important environmental issues in the last two decades. One of the most significant potential consequences of climate change may be alteration in regional hydrological cycle and river flow regimes. Increased temperature is expected to increase the peak flows in snowfed rivers of Himalayas. The changing pattern of regional temperature on flood peaks deserves urgent and systematic attention over a basin which provides an insight view of historical trends. Lower reaches of Satluj River is selected for the present study. Testing the significance of observed trends in flood peaks has received a great attention recently, especially in connection with climate change. The data series available was 48 years (1967-2010). The records were subjected to trend analysis by using both non-parametric (Mann-Kendall test) and parametric (linear regression analysis) procedures. For better understanding of the observed trends, flood peaks were computed into standardised flood peak indices (SFPI). These standardised data series were plotted against time and the linear trends observed were represented graphically. The analysis of flood peaks at different observation stations in lower reaches of Satluj River showed a large variability in the trends and magnitudes. The trend analysis results of flood peaks and gauge heights indicate that the flood peaks at all sites i.e. Rampur, Suni and Kasol show increasing but statistically insignificant trends. The trends in gauge height at all sites are also showing increasing trend but Kasol is statistically significant at 95% confidence level. The fast melting of glaciers, incessant monsoon rainfall and the synchronisation of the discharge peaks are the main causes of river floods. The past flood peaks will help us to observe the frequency of occurrence of floods in certain region and to determine whether the flood peaks in the past have been same with that of the present or whether there is any deviation in the trend in relation to climate change. Such studies will help in designing mitigation and adaptation strategies towards extreme hydrological events.
Źródło:
International Letters of Natural Sciences; 2015, 46
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the long-term variability of temperature trends and changes in surface air temperature in Kolkata Weather Observatory, West Bengal, India
Autorzy:
Khan, A.
Chatterjee, S.
Bisai, D.
Powiązania:
https://bibliotekanauki.pl/articles/108500.pdf
Data publikacji:
2015
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
temperature
trend analysis
Mann-Kendall test
Sen’s slope estimator
Kolkata
Opis:
The impact of climate change on annual air temperature has received a great deal of attention from climatologists worldwide. Many studies have been conducted to illustrate that changes in temperature are becoming evident on a global scale. Air temperature, one of the most important components of climate parameters, has been widely measured as a starting point towards the apprehension of climate change and variability. The main objective of this study is to analyse the temporal variability of mean monthly temperature for the period of 1941 to 2010 (70 years). To detect the magnitude of trend in mean monthly temperature time series, we have used non-parametric test methods such as The Mann-Kendall test, often combined with the Theil-Sen’s robust estimate of linear trend. Whatever test is used, the user should understand the underlying assumptions of both the technique used to generate the estimates of a trend and the statistical methods used for testing. The results of this analysis reveal that four months – January, February, March and December – indicate a decreasing trend in average temperature, while the remaining eight months have an increasing trend. The magnitude of Mann-Kendall trend statistic Zc for this declining temperature and the magnitude of slope for the months of January, February and December are confirmed at the high significance levels of α = 0.001, 0.01 and 0.1 respectively. Though, the overall trend is positive for monthly as well as seasonally efficient time series.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2015, 3, 2; 9-16
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Maximum daily rainfall analysis at selected meteorological stations in the upper Lusatian Neisse River basin
Autorzy:
Wdowikowski, M.
Kaźmierczak, B.
Ledvinka, O.
Powiązania:
https://bibliotekanauki.pl/articles/108530.pdf
Data publikacji:
2016
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
trend analysis
Mann-Kendall test
meteorological data
maximum rainfall
GED
Lusatian Neisse
IMWM-NRI
probabilistic distribution
Opis:
The scope of this study was to assess the usefulness of top probability distributions to describe maximum rainfall data in the Lusatian Neisse River basin, based on eight IMWM-NRI meteorological stations. The research material was composed of 50-year precipitation series of daily totals from 1961 to 2010. Misssing measurement data were estimated using a weighted average method. Homogeneity for refilled data were investigated by precipitation double aggregation curve. Correlation between the measurement data varied from 96 to 99% and did not indicate a violation of the homogeneity of rainfall data series. Variability of recorded daily precipitation maxima were studied by linear regression and non-parametric Mann-Kendall tests. Long-term period changes at maximum rainfalls for four stations remained statistically insignificant, and for the other four were significant, although the structure of maximums was relatively similar. To describe the measured data, there were used the Fréchet, Gamma, Generalized Exponential Distribution (GED), Gumbel, Log-normal and Weibull distributions. Particular distribution parameters were estimated using the maximum likelihood method. The conformity of the analyzed theoretical distributions with measured data was inspected using the Schwarz Bayesian information criterion (BIC) and also by the relative residual mean square error (RRMSE). Among others, the Gamma, GED, and Weibull distributions fulfilled the compliance criterion for each meteorological station respectively. The BIC criterion indicated GED as the best; however differences were minor between GED on the one hand and the Gamma and Weibull distributions on the other. After conducting the RRMSE analysis it was found that, in comparison to the other distributions, GED best describes the measured maximum rainfall data.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2016, 4, 1; 53-63
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatio-temporal analysis of rainfall trends in Chhattisgarh State, Central India over the last 115 years
Przestrzenna i czasowa analiza tendencji zmian opadów w stanie Chhattisgarh w środkowych Indiach w ciągu ostatnich 115 lat
Autorzy:
Nema, M. K.
Khare, D.
Adamowski, J.
Chandniha, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/292272.pdf
Data publikacji:
2018
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
change point
gridded data
modified Mann–Kendall test
rainfall variability
trend analysis
analiza trendu
dane gridowe
punkt zwrotny
zmienność opadów
zmodyfikowany test Manna– Kendalla
Opis:
A quantitative and qualitative understanding of the anticipated climate-change-driven multi-scale spatio- -temporal shifts in precipitation and attendant river flows is crucial to the development of water resources management approaches capable of sustaining and even improving the ecological and socioeconomic viability of rainfed agricultural regions. A set of homogeneity tests for change point detection, non-parametric trend tests, and the Sen’s slope estimator were applied to long-term gridded rainfall records of 27 newly formed districts in Chhattisgarh State, India. Illustrating the impacts of climate change, an analysis of spatial variability, multitemporal (monthly, seasonal, annual) trends and inter-annual variations in rainfall over the last 115 years (1901– 2015 mean 1360 mm·y–1) showed an overall decline in rainfall, with 1961 being a change point year (i.e., shift from rising to declining trend) for most districts in Chhattisgarh. Spatio-temporal variations in rainfall within the state of Chhattisgarh showed a coefficient of variation of 19.77%. Strong inter-annual and seasonal variability in regional rainfall were noted. These rainfall trend analyses may help predict future climate scenarios and thereby allow planning of effective and sustainable water resources management for the region.
Ilościowe i jakościowe rozpoznanie przewidywanych wielowymiarowych zmian opadów i towarzyszących im przepływów w rzekach spowodowanych zmianami klimatu jest decydujące dla rozwoju metod zarządzania zasobami wodnymi zdolnych utrzymać lub nawet usprawnić rentowność obszarów rolniczych zasilanych opadami. Zastosowano kilka testów jednorodności do wykrycia punktu zwrotnego, nieparametryczne testy trendu i estymator nachylenia Sena do analizy wieloletnich danych o opadach w 27 nowo utworzonych dystryktach stanu Chhattisgarh w Indiach. Ilustrując wpływ zmian klimatu, wyniki analizy przestrzennej zmienności, miesięcznych, sezonowych i rocznych trendów oraz zmienności między latami (1901–2015, średni opad 1360 mm·r–1) wykazały ogólne zmniejszenie ilości opadów w większości dystryktów stanu Chhattisgarh. Rok 1961 był punktem zwrotnym między rosnącym a malejącym trendem opadów. Współczynnik zmienności przestrzennej i czasowej opadów w stanie Chhattisgarh wynosił 19,77%. Zanotowano znaczną zmienność opadów między poszczególnymi latami i porami roku. Takie analizy trendów mogą być przydatne w przewidywaniu przyszłych scenariuszy klimatycznych, a w związku z tym – umożliwić wydajne i zrównoważone zarządzanie zasobami wodnymi regionu.
Źródło:
Journal of Water and Land Development; 2018, 36; 117-128
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of climate change on rice production at Khulna District, Bangladesh
Autorzy:
Hossain, N.
Saifullah, A.S.M.
Bhuiyan, S.H.
Uddin, N.
Rahman, M.
Powiązania:
https://bibliotekanauki.pl/articles/2049750.pdf
Data publikacji:
2019
Wydawca:
Fundacja na Rzecz Młodych Naukowców
Tematy:
rice
production
climate change
trend analysis
Bangladesh
gross domestic product
Mann-Kendall (MK) test
Rice Production
Opis:
In Bangladesh 164 million people depend on rice but due to climate change (CC) vulnerabilities the yield of rice is severely reducing. Therefore, this study aimed to explore the effects of CC on rice yield using recent trend analysis, Mann-Kendall (MK) trend test and correlation. For this study, the required climate and selected rice production data were collected from Bangladesh Meteorological Department (BMD) and Department of Agriculture Extension (DAE), Khulna. In time series statistics both parametric and nonparametric methods were applied to detect a monotonic trend of climatic variability and Aman rice production. Correlation between climatic variability and rice production was also investigated. The study exposed that the temperature and rainfall had an increasing trend and statistically significant whereas the relative humidity found decreasing. Overall, the bright Sunshine had positive trend but week. According to nonparametric trend test of climatic variability and Aman yield only minimum temperature showed a positive trend which found statistically significant. In contrast, Mann-Kendall trend test revealed that rainfall had positively significant while temperature had negative significant. The correlation revealed the Aman production is a strong response with minimum temperature whereas the Lona Coche showed a positive correlation with maximum temperature. The variation of Aman production exhibited a positive correlation with both Rainfall and humidity respectively and Lona Coche found a negative correlation. The sunshine had a week correlation against both yields. The findings suggest should give attention of temperature-tolerant rice varieties to mitigate possible adverse effects of CC.
Źródło:
Environment, Earth and Ecology; 2019, 3, 1; 42-54
2543-9774
2451-4225
Pojawia się w:
Environment, Earth and Ecology
Dostawca treści:
Biblioteka Nauki
Artykuł
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