Trend analysis and change point detection of air pollution index in Malaysia

Author(s):  
Y. Alyousifi ◽  
K. Ibrahim ◽  
W. Z. W. Zin ◽  
U. Rathnayake
2019 ◽  
Vol 40 (1) ◽  
pp. 308-323 ◽  
Author(s):  
Somayeh Salehi ◽  
Majid Dehghani ◽  
Sayed M. Mortazavi ◽  
Vijay P. Singh

2018 ◽  
Vol 27 (2) ◽  
pp. 801-807 ◽  
Author(s):  
Nurul Latiffah Abd Rani ◽  
Azman Azid ◽  
Saiful Iskandar Khalit ◽  
Hafizan Juahir ◽  
Mohd Saiful Samsudin

2019 ◽  
Vol 138 (1-2) ◽  
pp. 153-167 ◽  
Author(s):  
Litan Kumar Ray ◽  
Narendra Kumar Goel ◽  
Manohar Arora

2021 ◽  
Vol 46 (3) ◽  
pp. 223
Author(s):  
Barbaros Yaman ◽  
Mertol Ertuğrul

Studies associated with climate change and variability are of great importance at both the global and local scale in the global climate crisis. In this study, change-point detection and trend analysis were carried out on mean, maximum, minimum air temperatures and total precipitation based on monthly, seasonal and annual scale in Bartın province located in the western Black Sea Region of Turkey. For this aim, 4-different homogenei-ty tests (von Neumann test, Pettitt test, Buishand range test and standard normal homogeneity test) for change-point detection, Modified Mann–Kendall test and Şen’s innovative trend test for trend analysis, and Sen’s slope test for the magnitude estimation of trends were used. According to the test results, the summer temperatures in particular show increasing trends at the 0.001 significance level. Mean maximum temperature in August, mean minimum temperature in June and August, and mean temperature in July and August are in increasing trend at the 0.001 significance level. Over a 51 year period (1965–2015) in Bartın province, the highest rate of change per decade in air temperatures is in August (0.55°C for Tmax, 0.46°C for Tmin and 0.43°C for Tmean) based on Sen’s slope. However, the study showed that apart from October precipitation, there is no significant trend in monthly, seasonal and annual precipitation in Bartın. Increasing trends in mentioned climate variables are also visually very clear and strong in Şen’s innovative trend method, and they comply with the statistical results. As a result, the study revealed some evidence that temperatures will increase in the future in Bartın and its environs.


2020 ◽  
Vol 4 (3) ◽  
pp. 493-512
Author(s):  
Oluwaseun W. Ilori ◽  
Vincent O. Ajayi

Abstract This paper examined future trends with change detection in temperature and rainfall over three agro-climatic zones of West Africa. Historical (1961–2000) and projection (2020–2099) data of ensemble-mean of six RCMs that dynamically downscaled five GCMs that participated in CMIP5 obtained from Co-Ordinated Regional Climate Downscaling Experiment (CORDEX) were used. Standard normal homogeneity, Buishand’s, Pettitt’s, and Mann–Kendall test were used for change point detection and trend analysis at 5% significant level. Inter-annual anomaly and projected change in the seasonal cycle relative to historical mean were investigated. The ensemble-mean evaluation performed for the historical period (1961–2000) using CRU dataset revealed that the change point occurred in rainfall and temperature series in the 1970s and 1980s, while a significant increasing trend is observed in temperature in all climatic zones. Change-point detection test projects rainfall series to be homogeneous as significant change point is expected to occur in temperature for all zones under RCP4.5 and RCP8.5 for near (2020–2059) and far-future (2060–2099). For the near-future, an increase in the mean temperature between 0.5–1.30 ℃ and 0.19–1.67 ℃ is projected to occur under RCP4.5 and RCP8.5 respectively. Projected relative change in seasonal cycle shows that winter months may witness increase in rainfall amounts under RCP4.5 but significantly dry under RCP8.5 in near and far-future as temperature is expected to become warmer in all months. Rainfall anomaly projects the Sahel to have a reduced amount of rainfall compared to other zones as temperature anomaly reveals a continuous increase in all the zones under the two RCPs. The results of this study show that climate change will intensify in West Africa in the future.


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