scholarly journals Analysis of long-term climatic changes at Hodeidah-Yemen during the period between 1984 and 2019

2021 ◽  
Author(s):  
Abkar Ali Iraqi ◽  
AbdAlla Mohammed AbdAlla
Keyword(s):  
Climatic Variability ◽  
Arab Country ◽  
Climatic Fluctuations ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Mk Test ◽  
Slope Estimator ◽  
Annual Means ◽  
C 50 ◽  
Increasing Trends

Abstract Yemen is one of the Arab country that is vulnerable to climate changes, and this is clear from the indicators of impact on water resources, coastal zone environments, etc. This work focuses on studying the climatic variability at Hodeidah city-Yemen during the period between 1984 and 2019. This study aimed to characterize trends in mean monthly, seasonal and annual temperature. To attain these objectives the collected data were analyzed using both parametric (linear regression) and non-parametric (Mann–Kendall, Spearman and Sen's slope estimator tests) methods to detect the trend and the magnitudes of rates of changes of temperature over time. Analysis of data indicates clear climatic fluctuations of temperature. The annual means of temperature during the period of study were varied between 26.9°C and 30.1°C. The warmest years were observed during the more recent years of the study period ( 2005 to 2018). The increasing rate of annual temperature is about + 0.075°C /year, + 0.37°C/5year, + 0.75°C/decade ,+2.53°C, over the whole period of study(1985 to 2019), + 3.7°C/50 year and increase to + 4.85°C in 2050. On a monthly timescale, there are similar magnitudes of rates of change from December to September with highest rates in October and November. The results also showed that most months and seasons have significant positive trends in temperature and (Z-α/2) values of the MK Test > 1.96 and positive value of Sen’s slope estimator indicates significant an increasing trend towards warmer years. Anomalies of temperature confirm significant increasing trends towards warmer years (2000s to 2019).

scholarly journals Analysis of long-term climatic changes at Hodeidah-Yemen during the period between 1984 and 2019

2021 ◽  
Author(s):  
Abkar Ali Iraqi ◽  
AbdAlla Mohammed AbdAlla
Keyword(s):  
Climatic Variability ◽  
Arab Country ◽  
Climatic Fluctuations ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Mk Test ◽  
Slope Estimator ◽  
Annual Means ◽  
C 50 ◽  
Increasing Trends

Abstract Yemen is one of the Arab country that is vulnerable to climate changes, and this is clear from the indicators of impact on water resources, coastal zone environments, etc. This work focuses on studying the climatic variability at Hodeidah city-Yemen during the period between 1984 and 2019. This study aimed to characterize trends in mean monthly, seasonal and annual temperature. To attain these objectives the collected data were analyzed using both parametric (linear regression) and non-parametric (Mann–Kendall, Spearman and Sen's slope estimator tests) methods to detect the trend and the magnitudes of rates of changes of temperature over time. Analysis of data indicates clear climatic fluctuations of temperature. The annual means of temperature during the period of study were varied between 26.9°C and 30.1°C. The warmest years were observed during the more recent years of the study period ( 2005 to 2018). The increasing rate of annual temperature is about + 0.075°C /year, + 0.37°C/5year, + 0.75°C/decade ,+2.53°C, over the whole period of study(1985 to 2019), + 3.7°C/50 year and increase to + 4.85°C in 2050. On a monthly timescale, there are similar magnitudes of rates of change from December to September with highest rates in October and November. The results also showed that most months and seasons have significant positive trends in temperature and (Z-α/2) values of the MK Test > 1.96 and positive value of Sen’s slope estimator indicates significant an increasing trend towards warmer years. Anomalies of temperature confirm significant increasing trends towards warmer years (2000s to 2019).

scholarly journals Water vapor pressure trends in south and southwest Iran

MAUSAM ◽  
2021 ◽  
Vol 68 (2) ◽  
pp. 335-348
Author(s):  
YOUNES KHOSRAVI ◽  
HASAN LASHKARI ◽  
HOSEIN ASAKEREH
Keyword(s):  
Time Series ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Ground Station ◽  
Mk Test ◽  
Slope Estimator ◽  
The Persian Gulf

Recognitionanddetectionofclimaticparameters inhave animportant role inclimate change monitoring. In this study, the analysis of oneofthe most importantparameters, water vapor pressure (WVP), was investigated. For this purpose, two non-parametric techniques, Mann-Kendall and Sen's Slope Estimator, were used to analyze the WVP trend and to determine the magnitude of the trends, respectively. To analyze these tests, ground station observations [10 stations for period of 44 years (1967-2010)] and gridded data [pixels with the dimension of 9 × 9 km over a 30-year period (1981-2010)] in South and SouthwestofIran were used. By programming in MATLAB software, the monthly, seasonal and annual WVP time series were extracted and MK and Sen's slope estimator tests were done. The results of monthly MK test on ground station observations showed that the significant downward trends are more considerable than significant upward trends. It also showed that the WVP highest frequency was more in warm months, April to September and the highest frequency of significant trends slope was in February and May. The spatial distribution of MK test of monthly gridded WVP time series showed that the upward trends were detected mostly in western zone and near the Persian Gulf in August. On the other hand, the downward trends through months. The maximum and minimum values of positive trends slope occurred in warm months and cold months, respectively. The analysis of the MK test of the annual WVP time series indicated the upward significant trends in the southeast and southwest zones of study area.  

Spatio-temporal Trend Detection of Rainfall for Climate Change Assessment in Ahmedabad-Gandhinagar District of Gujarat State, India

2021 ◽  
Vol 7 (1) ◽  
pp. 69-78
Author(s):  
Geeta S. Joshi ◽  
Payal Makhasana
Keyword(s):  
Climate Change ◽  
Rain Gauge ◽  
The State ◽  
Monthly Rainfall ◽  
Trend Detection ◽  
Annual Rainfall ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Mk Test ◽  
Slope Estimator

The present research aims to assess the historical change in rainfall patterns with the changing climate in the Ahmedabad-Gandhinagar district in the state of Gujarat in India. The Mann-Kendall (MK) test along with Sen’s slope estimator have been used for detecting the trend of rainfall data series. The trend of annual rainfall is carried out for – (1) six rain gauge stations established by the State Water Data Center (SWDC) and (2) 11 grid data available from the National Center for Environmental Prediction-Climate Forecast System Reanalysis (NCEP-CFSR) for 35 years starting from 1979 to 2013. Results obtained from these two data sets for the trend detection were found consistent. Furthermore, the analyses of annual and monthly rainfall using MK test and Sen’s slope estimator at six rain gauge stations are carried out in three time periods i.e. 1974-1987, 1988-2001 and 2002-2016. The inverse distance weighted (IDW) method of interpolation is used for the results obtained from the spatial distribution of the temporal rainfall trend for interpolating the station value over the study area. Annual rainfall for data length of 1979 to 2013 shows an increasing trend. The trend of annual and monthly rainfall for July and September shows a positive trend for the span 2002-2016. This study would be useful to the water resource department and policymakers for climate change adaptation in the study area.

scholarly journals Analysis of precipitation variability over Satluj Basin, Himachal Pradesh, India: 1901–2013

2020 ◽  
Author(s):  
Nity Tirkey ◽  
P. K. Parhi ◽  
A. K. Lohani ◽  
S. K. Chandniha
Keyword(s):  
Climatic Variability ◽  
Himachal Pradesh ◽  
The State ◽  
Spatial And Temporal Variation ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Seasonal Time Series ◽  
Slope Estimator ◽  
Level Of Significance ◽  
The Impact

Abstract Himachal Pradesh is a mountainous state in the Indian Himalayas, which spreads over an area of 55,000 km2. The state has a unique geography, which influences the climatic variability of the state. In the present study, Satluj basin has been considered as a study area. This basin experiences frequent floods, erratic distribution of rainfall and climatic variabilities, which causes extensive damage over the basin. Precipitation is one of the most crucial meteorological variables which determines the impact of climate change in the Himalayan landmass. For spatial and temporal variation of precipitation, long-term precipitation data of 113 years (1901–2013) was utilized. Further, non-parametric, i.e. Mann–Kendall (MK) and modified Mann–Kendall (MMK) tests, were performed to check possible trends and Sen's slope estimator (SSE) test was used for determining the change in magnitude over the basin at 95% level of significance. The entire analysis was performed on a monthly, annual and seasonal (pre-monsoon, monsoon, post-monsoon and winter) basis. In this study, it was noticed that both positive and negative trends are detected in monthly and seasonal time series. It was also noticed that similar results have been estimated in MK, MMK and Sen's slope estimator tests during 1901–2013.

scholarly journals Rainfall trend and variability over Opak River basin, Yogyakarta, Indonesia

2020 ◽  
Vol 1000 (1000) ◽  
Author(s):  
Wakhidatik Nurfaida ◽  
Hendra Ramdhani ◽  
Takenori Shimozono ◽  
Indri Triawati ◽  
Muhammad Sulaiman
Keyword(s):  
River Basin ◽  
Water Resource ◽  
Rainfall Intensity ◽  
Kendall Test ◽  
Rainfall Data ◽  
Positive Trend ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Slope Estimator

Rainfall intensity seems to be increasing nowadays due to climate change as presented in many studies of both global and regional scale. Consequently, cities worldwide are now more vulnerable to flooding. In Indonesia, increasing frequency of floods was reported for the past decades by The National Agency for Disaster Countermeasure (BNPB). To understand the rainfall changes, long-term trend evaluation over a specific area is then crucial due to the large variability of spatial and temporal rainfall distribution. This study investigates the homogeneity and trend of rainfall data from 20 stations over the Opak River basin, Yogyakarta, Indonesia. A long-term ground observation rainfall data whose period varies from 1979 to 2019 were analyzed. Non-parametric Mann – Kendall test was applied to assess the trend, while the magnitude was calculated using the Sen’s slope estimator. An increasing annual maximum of daily rainfall intensity was observed at four stations on a 0.95 confidence level based on the Mann – Kendall test, while the Sen’s slope estimator shows a positive trend at almost all stations. The trend of heavy rainfall frequency was also found to be significantly increased, with only one station showed a decreasing trend. Furthermore, this paper also described the spatial and temporal rainfall variability. Positive trend was mostly found during the rainy season, while the negative trend occurred during the dry season. This could pose a challenge for water resource management engineering and design, such as water supply systems or reservoir management. Understanding this phenomena will benefit hydrologists in preparing future water resource engineering and management.

scholarly journals Rainfall trend analysis using Mann-Kendall and Sen’s slope estimator test in West Kalimantan

2021 ◽  
Vol 893 (1) ◽  
pp. 012006
Author(s):  
F Aditya ◽  
E Gusmayanti ◽  
J Sudrajat
Keyword(s):  
Climate Change ◽  
Rainfall Variability ◽  
Annual Rainfall ◽  
Sen’S Slope Estimator ◽  
West Kalimantan ◽  
Rainfall Analysis ◽  
Sen’S Slope ◽  
Rainfall Trends ◽  
Slope Estimator ◽  
The Impact

Abstract Climate change has been a prominent issue in the last decade. Climate change on a global scale does not necessarily have the same effect in different regions. Rainfall is a crucial weather element related to climate change. Rainfall trends analysis is an appropriate step in assessing the impact of climate change on water availability and food security. This study examines rainfall variations and changes at West Kalimantan, focusing on Mempawah and Kubu Raya from 2000-2019. The Mann-Kendall (MK) and Sen's Slope estimator test, which can determine rainfall variability and long-term monotonic trends, were utilized to analyze 12 rainfall stations. The findings revealed that the annual rainfall pattern prevailed in all locations. Mempawah region tends to experience a downward trend, while Kubu Raya had an upward trend. However, a significant trend (at 95% confidence level) was identified in Sungai Kunyit with a slope value of -33.20 mm/year. This trend indicates that Sungai Kunyit will become drier in the future. The results of monthly rainfall analysis showed that significant upward and downward trends were detected in eight locations. Rainfall trends indicate that climate change has occurred in this region.

scholarly journals Spatiotemporal Pattern Assessment of Precipitation for the Wainganga Sub-Basin

2020 ◽  
Vol 15 (3) ◽  
pp. 515-525
Author(s):  
Aradhana Thakur ◽  
Prabhash Kumar Mishra ◽  
A K Nema ◽  
Souranshu Prasad Sahoo
Keyword(s):  
India Meteorological Department ◽  
Kendall Test ◽  
Spatiotemporal Pattern ◽  
Precipitation Trend ◽  
Monsoon Precipitation ◽  
Sen’S Slope ◽  
Mk Test ◽  
Shift Analysis ◽  
Hydrologic System ◽  
Slope Estimator

Precipitation is the major component of a hydrologic system, which significantly influences the planning and management of the water resources. The present study is principally concerned with the shifting of precipitation patterns over time. This study attempted to explain the precipitation trend for 65 years (1951-2015) using a Mann-Kendall test (MK test) and trend magnitude by Sen's slope estimator. Daily gridded data procured from India Meteorological Department (IMD) of 0.25º × 0.25º degrees to find the monthly and seasonal variability of precipitation. Eighty-five grids were falling in the basin processed for the periods from 1951 to 2015. The statistical analysis revealed that the average annual precipitation (AAP) and monsoon precipitation following the insignificant downward trend with Z statistics 0.10 and 1.23 and Sen's slope 0.79 and 0.76, respectively, over the basin. The shift analysis shows the AAP and monsoon precipitation increased significantly during 1951-61, whereas during the 1962-2015 rise in precipitation was insignificant. That changes in precipitation over the Wainganga sub-basin (WSB) may occur probably due to a rising trend of temperature. Therefore, nature-based climate solutions are the best way to endure the condition.

scholarly journals Spatiotemporal Trend Analysis of the Mean Annual Rainfall in Senegal

2016 ◽  
Vol 12 (12) ◽  
pp. 231 ◽  
Author(s):  
Lamine Diop ◽  
Ansoumana Bodian ◽  
Dior Diallo
Keyword(s):  
Kendall Test ◽  
Annual Rainfall ◽  
Positive Trend ◽  
Sen’S Slope Estimator ◽  
Small Areas ◽  
Sen’S Slope ◽  
Trend Magnitude ◽  
North East ◽  
Spatiotemporal Trends ◽  
Slope Estimator

The spatiotemporal trends of annual rainfall in Senegal during 1940 - 2013 were investigated using the Mann–Kendall test and Theil–Sen’s slope estimator. Theil and Sen's slope estimator test was used for finding the magnitude of change over a time period. Inverse Weight Distance (IDW) technique in Arc GIS 10.2 was used to investigate spatial patterns of the trends over the entire country. For the period 1940-2013, the results of the analysis showed negative trends in annual rainfall at the whole country except for the Bakel station which exhibits a positive trend but not significant. While for the period 1984 - 2013, all the stations show a positive trend with 07 out of 22 stations exhibiting a significant trend at the 95% confidence interval. The spatial distribution of trend during the period 1940- 2013 showed a significant negative trend in the whole study of area except small areas located at the extreme South Est and West as well as North East and West. The trend magnitude varies between -4.41mm/year to 1.34 mm for the period 1940-2013 with a maximum negative magnitude at the Tambacounda station. For 1984-2013, the trend magnitude is positive for the whole country with values varying between 2.67 mm/year at Goudiry and 12.2 mm/year at Ziguinchor. Magnitudes are greater than 5 mm/year, for stations with significant positive trend.

Rainfall and river flow trends using Mann–Kendall and Sen’s slope estimator statistical tests in the Cobres River basin

2015 ◽  
Vol 77 (2) ◽  
pp. 1205-1221 ◽  
Author(s):  
Richarde Marques da Silva ◽  
Celso A. G. Santos ◽  
Madalena Moreira ◽  
João Corte-Real ◽  
Valeriano C. L. Silva ◽  
...  
Keyword(s):  
River Basin ◽  
River Flow ◽  
Statistical Tests ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Slope Estimator

scholarly journals Trend Analysis of Annual and Monthly Rainfall in Erbil City, Kurdistan Region, Iraq

2019 ◽  
Vol 9 (2) ◽  
pp. 30-36 ◽  
Author(s):  
Saud A. Hussien ◽  
Basil Y. Mustafa ◽  
Farzand K. Medhat
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Trend Analysis ◽  
Linear Regression Analysis ◽  
Monthly Rainfall ◽  
Annual Rainfall ◽  
Sen’S Slope Estimator ◽  
Sen’S Slope ◽  
Slope Estimator ◽  
Non Parametric

The objective of this study is to identify the trend for the annual and monthly rainfall time series data from 1963–1964 to 2018–2019 for Erbil city rainfall gauging station. The trend analysis was conducted for only rainy months (from October to May) using the non-parametric Mann-Kendall test, whereas a non-parametric Sen’s slope estimator was used to determine the magnitude of the trend. A functional relationship has been developed between variables using linear regression analysis to determine a linear trend of rainfall for the study area. The annual trend analysis revealed negative (decreasing) trend because the Kendall’s tau (Z) value and the Sen’s slope estimator magnitude were both negative and found to be −0.093 and −1.37, respectively, and the slope of the linear regression analysis was also negative and equal to −0.9148 mm/year, which represents the rate of yearly annual rainfall decreasing trend. Considering the result of monthly rainfall, the trend analysis of rainfall has suggested that there is a trend variation of rainfall in the rainy months. Further, the analysis revealed a negative (decreasing) trend for months November, January, February, March, April, and May and positive (increasing) trend for months October and December. This study is important as it greatly contributes in water resources system planning and management in this region. Furthermore, the results obtained in this work are promising and might help hydraulic civil and water resource engineers in the design of hydraulic structures.

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