scholarly journals Tendências e Prognósticos de Chuvas em Seis Microrregiões do Estado da Paraíba (Trends and Forecasts of Rain in Six Regions of Paraíba State)

2011 ◽  
Vol 4 (2) ◽  
pp. 252
Author(s):  
Francisco de Assis Salviano de Sousa ◽  
Heliene Ferreira De Morais ◽  
Vicente de Paulo Rodrigues Da Silva
Keyword(s):  
Time Series ◽  
Prognostic Model ◽  
Kendall Test ◽  
Statistical Test ◽  
The State ◽  
Increasing Trend ◽  
Mann Kendall Test ◽  
Standard Deviations ◽  
The One

Neste trabalho foram utilizadas séries temporais de precipitação pluviométrica de 54 municípios para estimar tendências e prognósticos de chuvas em seis microrregiões do estado da Paraíba, com base no teste estatístico de Mann-Kendall e em modelo prognóstico para cenários com horizontes de 50 e 100 anos. Os maiores valores de desvios-padrão foram registrados na microrregião do Litoral, variando entre 481,4 mm no município de Santa Rita e 601,1 mm em João Pessoa. Os menores ocorreram no Cariri, oscilando entre 189,9 mm em Cabaceiras e 273,3 mm em Monteiro. Observou-se alternância de tendências crescente e decrescente nos vários municípios estudados, com destaque para a microrregião do Brejo que apresentou tendência crescente de chuva em todos os municípios. Quanto aos prognósticos da precipitação, Alhandra, situada na microrregião do Litoral, apresentou os prognósticos mais elevados. Nesse município a estimativa de chuvas para 2050 é de 1791,0 mm e para 2100 é de 1962,6 mm. A microrregião do Cariri foi a que apresentou os menores prognósticos. A estimativa para Picuí em 2050 é de 369,7 mm e para São Sebastião do Umbuzeiro, em 2100 é de 266,5 mm.  Palavras-chave: Teste de Mann-Kendall, modelo prognóstico e precipitação pluvial Trends and Forecasts of Rain in Six Regions of Paraíba State  ABSTRACT In this work we used time series of rainfall of 54 municipalities to estimate trends and forecasts of rain in six regions of the State of Paraíba-based statistical test of Mann-Kendall and prognostic model for scenarios with horizons of 50 and 100 years. The highest values of standard deviations were recorded in the micro region of the Coast, ranging from 481.4 mm in Santa Rita and 601.1 mm in Joao Pessoa. The minors in Cariri, ranging between 189.9 mm and 273.3 mm in Cabaceiras and Monteiro. Observed alternating increasing and decreasing trends in the various districts studied, especially the micro to the Swamp presented increasing trend of rainfall in all municipalities. As for predictions of precipitation, Alhambra, located in the micro region of the Coast had the highest predictions. In this municipality, the estimate for 2050 rainfall is 1791.0 mm and for 2100 is 1962.6 mm. The micro Cariri was the one with the lowest predictions. The estimate for Picuí in 2050 is 369.7 mm and São Sebastião do Umbuzeiro in 2100 is 266.5 mm.  Keywords: Mann-Kendall test, prognostic model and rainfall

scholarly journals Re-evaluation of the Power of the Mann-Kendall Test for Detecting Monotonic Trends in Hydrometeorological Time Series

2020 ◽  
Vol 8 ◽  
Author(s):  
Fan Wang ◽  
Wei Shao ◽  
Haijun Yu ◽  
Guangyuan Kan ◽  
Xiaoyan He ◽  
...  
Keyword(s):  
Time Series ◽  
Kendall Test ◽  
Mann Kendall Test

scholarly journals Trend analyses of regional time series of temperatures and rainfall of the Tapi basin

2021 ◽  
Vol 22 (1) ◽  
pp. 48-51
Author(s):  
GANESH D. KALE
Keyword(s):  
Time Series ◽  
Kendall Test ◽  
Temperature Variations ◽  
Trend Analyses ◽  
Slope Test ◽  
Climate Change Information ◽  
Mann Kendall Test ◽  
Maximum Temperatures ◽  
Planning Development ◽  
Tapi Basin

Climate change information at the scale of basin is vital for planning, development and use of water. The Tapi basin is climatically responsive. Hydrological response of a basin is based mainly on rainfall and temperature. Variations in climate at regional scales impacts fundamental features of our life. Thus, in the present work, trend analyses of regional time series (1971-2004) of minimum, mean, maximum temperatures and rainfallis performed for monthly, annual and seasonal scales for the Tapi basin. Correlogram is utilized for evaluation of dependence of data. Mann-Kendall test and Mann-Kendall test with block bootstrapping are applied for the evaluation of trend significance. Sen’s slope test is applied for the evaluation of trend magnitude. Sequential Mann-Kendall test is applied for assessment of beginning and end of the trend. Statistically significant positive trends are detected in regional annual and winter Tmean time series with their beginning in years 1974 and 1972, respectively.

Precipitation Trend Analysis by Mann-Kendall Test: A Case of Tianchang County Anhui Province, China

2013 ◽  
Vol 864-867 ◽  
pp. 2218-2223 ◽  
Author(s):  
Elsie Akwei ◽  
Bao Hong Lu ◽  
Han Wen Zhang
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Trend Analysis ◽  
Null Hypothesis ◽  
Kendall Test ◽  
Anhui Province ◽  
Significant Trend ◽  
Precipitation Data ◽  
Precipitation Time Series ◽  
Mann Kendall Test

The purpose of this research is to study the temporal variability of precipitation time series of Tianchang County in Anhui Province, China to aid in the understanding of the state of the hydrology of the catchment. Trend analysis of one of the main component of the water balance of a catchment and a climate variable, precipitation was conducted with the aim of detecting a possible trend in the precipitation time series of Tianchang County, the non-parametric Mann-Kendall test was applied to precipitation series from 1951-2010 of Tianchang County. It was performed using Trend (version 1.0.2) to identify the significant positive or negative trends in the precipitation data if any. The 59 years period of precipitation data for the different towns in whole area showed, on the whole, some significant trend at an alpha level of 0.01 and 0.05 when grouped into the four seasons present in the area. The trend analysis revealed an overall upward and significant trend in five towns namely Datong, Xinjie, Shiliang, Qinlan and Tongcheng with downward statistically non-significant trend in the other ten areas .Using hypothesis testing, the null hypothesis states that there is no trend and alternative state there is a trend. From the results we reject the null hypothesis within the level of confidence 0.05 and 0.01. The rising rate of precipitation in some months and decreasing in others signifies an overall random pattern in the time series. This result is a part contribution to the effect of Climate change on hydrology and indicates that there is still room for research on the impact of climate change to ensure sustainable development in future.

scholarly journals Time Series Trend and Variability Analysis of Temperature and Rainfall in West Shewa Zone of Oromia, Ethiopia

2021 ◽  
Author(s):  
Daniel Assefa ◽  
Mesfin Mengistu
Keyword(s):  
Time Series ◽  
Minimum Temperature ◽  
Kendall Test ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Variability Analysis ◽  
Increasing Trend ◽  
Systematic Planning ◽  
Temperature Records ◽  
C 30

Abstract BackgroundThe paper focus on time series trend and variability analysis of observed rainfall and temperature records from 16 stations during 1985-2015. ResultsBoth the summer and annual rainfall have an increasing trend but not statistically significant. Regards to variability, low to very high levels of variability were recorded according to the seasons and annual rainfall, whereas, moderate to extremely high levels of variability were observed. The result of the Mann Kendall test portrays that the mean minimum temperature was raised by 0.05 oC, while the maximum temperature was increased rose by 0.03 oC/30 years. The monthly maximum temperature also shows an increasing trend with the lowest record during August (22.05 oC) and the highest in the March (26.49 oC) except in the month of November and December. Similarly, an increasing trend was observed with a mean monthly minimum temperature with the lowest mean of 8.42Co in December and the highest mean of 11.12 oC recorded in April. Besides, a low level of variability was seen both in the case of minimum and maximum temperature were observed in all months. ConclusionsTherefore, since the observed trends of both temperature and total rainfall show abnormal shifts, there is an urgent need for policymakers to design systematic planning and management activities to rain-fed agriculture.

scholarly journals Rainfall Dynamics of Terengganu Malaysia and Its Recent Trends Analysis Using the Mann-Kendall Test.

2014 ◽  
Vol 4 (2) ◽  
pp. 372-381 ◽  
Author(s):  
Musa Garba Abdullahi ◽  
Mohd Ekhwan Toriman ◽  
Mohd Barzani Gasim ◽  
Hafizan Juahir
Keyword(s):  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Kendall Test ◽  
Southwest Monsoon ◽  
The State ◽  
Northeast Monsoon ◽  
Monsoon Period ◽  
Mann Kendall Test ◽  
Recent Trends ◽  
Increasing Trends

This study investigated the pattern and trends of the daily rainfall data in Terengganu Malaysia based on seasonal rainfall indices. The statistics of rainfall indices were calculated in terms of their means for seven stations in Terengganu Malaysia for the period 2000 to 2012. The findings indicate that the trend in the study area has no significant changes in stations (1, 4 and 6) while station (2, 3, 5 and 7) shows significant changes and southwest monsoon had the greatest impact on the whole stations, particularly in characterizing the rainfall pattern of the area. During this season, the study area could be considered as the wettest region since all rainfall indices tested are higher than in other neighboring state of the Peninsula. Otherwise, the northwest of the area is denoted as the driest part of the state during the northeast monsoon period. The northwest of the state is less influenced by the northeast monsoon because of the existence of the Titiwangsa Range, which blocks some part of the region from receiving heavy rainfall. On the other hand, it is found that the areas with lowlands are strongly characterized by the northeast monsoonal flow.The results of the Mann-Kendall test, shows that, trends of the total amount of rainfall during the southwest monsoon decrease at some of the stations. The rainfall intensity increases in contrast, increasing trends in the total amount of rainfall were observed at three stations during the northeast monsoon, which give rise to the increasing trend of rainfall intensity. The results for the combined stations in both seasons indicate that there are no significant changes in trends during the extreme events for the Terengganu Malaysia. However, a smaller number of significant trends were found for extreme intensity. 

scholarly journals A Consistent Test of Stationary-Ergodicity

1993 ◽  
Vol 9 (4) ◽  
pp. 589-601 ◽  
Author(s):  
Ian Domowitz ◽  
Mahmoud A. El-Gamal
Keyword(s):  
Time Series ◽  
State Space ◽  
Estimation Error ◽  
Asymptotic Properties ◽  
Markov Operator ◽  
Statistical Test ◽  
The State ◽  
Consistent Test ◽  
Markovian Processes ◽  
Density Space

A formal statistical test of stationary-ergodicity is developed for known Markovian processes on ℝd This makes it applicable to testing models and algorithms, as well as estimated time series processes ignoring the estimation error. The analysis is conducted by examining the asymptotic properties of the Markov operator on density space generated by the transition in the state space. The test is developed under the null of stationary-ergodicity, and it is shown to be consistent against the alternative of nonstationary-ergodicity. The test can be easily performed using any of a number of standard statistical and mathematical computer packages.

scholarly journals Influência da Urbanização no Clima da Cidade de Campina Grande-PB (Influence of Urbanization on Climate of the Campina Grande City–PB)

2011 ◽  
Vol 4 (1) ◽  
pp. 134 ◽  
Author(s):  
Francisco de Assis Salviano de Sousa ◽  
Heliene Ferreira de Morais ◽  
Vicente De Paulo Rodrigues da
Keyword(s):  
Time Series ◽  
Relative Humidity ◽  
Air Temperature ◽  
Anthropogenic Activities ◽  
Urban Climate ◽  
Kendall Test ◽  
Annual Rainfall ◽  
Abrupt Changes ◽  
Mann Kendall Test ◽  
Deviation Coefficient

A expansão de cidades produz diversos impactos no ambiente urbano causado por atividades antropogênicas. Este estudo avaliou o efeito da urbanização no clima da cidade de Campina Grande com base em dados mensais de temperatura média do ar, precipitação pluvial, umidade relativa do ar e insolação no período de 1963 a 2004. O método de desvios cumulativos foi utilizado para detectar mudanças abruptas nas séries temporais. Dois períodos de estudo foram estabelecidos: pré-urbano intenso PRÉ-UI (1963-1985) e pós-urbano intenso PÓS-UI (1986-2004). Para cada variável climática foram obtidas estatísticas como: médias, desvio-padrão, coeficiente de variação (CV) e autocorrelação serial. Foram avaliadas as diferenças entre as médias dos períodos PRÉ-UI e PÓS-UI através do teste de t-Student. Também foi usado o teste Mann-Kendall para avaliar as tendências das séries temporais no período total estudado. A temperatura média do ar apresentou tendência crescente, enquanto umidade relativa apresentou tendência decrescente, todas estatisticamente significativas ao nível de 1% através do teste de Mann-Kendall. A série de precipitação pluvial não apresentou tendência estatisticamente significativa. A variabilidade da precipitação pluvial intra-anual, expressa pelo CV, é muito alta e variou de 30 a 89% durante o período analisado. A variabilidade anual da precipitação pluvial é cerca de 30% da variabilidade intra-anual. A temperatura do ar demonstrou persistência natural através dos valores do coeficiente de autocorrelação, para os primeiros lags.Palavras-chave: Clima urbano, Mann-Kendall e variáveis climáticas  Influence of Urbanization on Climate of the Campina Grande City–PB ABSTRACTThe expansion of cities produces different impacts in the urban environment caused by anthropogenic activities. This study evaluated the effect of urbanization on climate of the Campina Grande city based on monthly data of average air temperature, rainfall, relative humidity and sunshine in the period 1963 to 2004. The cumulative deviation method was used to detect abrupt changes in time series. Two study periods were established: intense urban pre-PRE-UI (1963-1985) and after intense urban POST-IU (1986-2004). For each climate variable, statistics were obtained as averages, standard deviation, coefficient of variation (CV) and serial autocorrelation. We evaluated the differences between the mean pre-and post-IU through the IU Student t test. It was also used Mann-Kendall test to assess trends in time series over the entire period studied. The average air temperature showed an ascending trend, while relative humidity showed a declining trend, all statistically significant at 1% through the Mann-Kendall test. The series of rainfall did not show a statistically significant trend. The variability of intra-annual precipitation, expressed as CV, is very high and ranged from 30 to 89% during the period analyzed. The variability of annual rainfall is about 30% of intra-annual variability.The air temperature showed persistence through the natural values the autocorrelation coefficient for the first lags.  Keywords: Urban climate, Mann-Kendall and climatic variables

scholarly journals Statistical assessment of rainfall variability and trends in northeastern Algeria

2019 ◽  
Vol 40 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Noureddine Merniz ◽  
Ali Tahar ◽  
Amine M. Benmehaia
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Rainfall Variability ◽  
Temporal Trends ◽  
Kendall Test ◽  
Series Data ◽  
Mann Kendall Test ◽  
Slope Estimator ◽  
Northeastern Algeria ◽  
Rainy Days

Abstract In the present study, time series for annual, monthly rainfall and number of rainy days per year were analysed to quantify spatial variability and temporal trends for 22 rainfall stations distributed in northeastern Algeria for the period 1978–2010. The Mann–Kendall test and the Sen’s slope estimator were applied to assess the significance and magnitude of the trend. The results showed that precipitation decreases spatially from North to South and from East to West. The application of the Mann–Kendall test (for 0.05% threshold) to the time series data showed that for annual precipitation, no station showed statistically significant trends, unlike the number of rainy days, where there was a significant negative trend in four stations (Jijel, Constantine, Oum El Bouaghi and Tébessa). For the monthly time series, significant positive trends were observed during the months of September in the coastal stations and July for the plateaus and southern Saharan Atlas stations, while significant negative trends were recorded during the months of February and March for the stations of the extreme East in the study area. These results revealed that for the period analysed, there was no significant climate change in northeastern Algeria but there is a seasonal delay having important agroecological implications.

Sign in / Sign up

Export Citation Format

Share Document