TREND ANALYSIS OF RAINFALL, TEMPERATURE AND RUNOFF DATA: A CASE STUDY OF RANGOON WATERSHED IN NEPAL

2017 ◽  
Vol 5 (3) ◽  
pp. 21-38 ◽  
Author(s):  
Amar Bahadur Pal ◽  
Deepak Khare ◽  
Prabhash Kumar Mishra ◽  
Lakhwinder Singh
Keyword(s):  
Trend Analysis ◽  
Research Work ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Original Research ◽  
Positive Trend ◽  
Sen’S Slope ◽  
Z Value ◽  
Trend Direction

Purpose: The study has been carried out to investigate and assess the significance of the potential trend of three variables viz. rainfall, temperature and runoff over the Rangoon watershed in Dadeldhura district of Nepal.Methodology: In this study, trend analysis has been carried out on monthly, seasonal and annual basis using the data period between 1979 to 2010 for rainfall and temperature and 1967 to 1996 for runoff. Mann-Kendall test and Sen’s slope estimate test were applied to identify the existing trend direction and Sen’s slope estimator test were used to detect the trend direction and magnitude of change over time.Main findings: The most important findings are, i) There is warming trends over the Rangoon watershed as Mann-Kendall statistic (Z-value) for most of the maximum temperature values are positive, ii) Rainfall and runoff affected by fluctuations every year though the annual rainfall showing a rising trend whereas runoff showing a falling trend. The rainfall seasonal trend analysis indicates that monsoon and post-monsoon period showed a positive rainfall trend with z statistics of +1.93, and +1.12 respectively, whereas pre-monsoon and winter seasons showed a negative trend with z statistics of -1.02, and -0.54 respectively. However, the annual rainfall in the Rangoon watershed showed a positive trend with a z value of +1.70.Importance of this study: This case study has been undertaken to investigate the trends of important climatic variables viz. rainfall, temperature which have a direct impact on the agriculture of the region.Originality / Novelty of study: This is an original research work undertaken under the M. Tech programme during 2016-17 at IIT Roorkee by the scholar Er. Amar Bahadur Pal from Nepal. 

Rainfall and Temperature Trends in Jagtial District of Telangana State

2021 ◽  
pp. 47-59
Author(s):  
N. Navatha ◽  
G. Sreenivas ◽  
R. Umareddy
Keyword(s):  
Trend Analysis ◽  
Minimum Temperature ◽  
Negative Trend ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Sen’S Slope ◽  
Average Maximum ◽  
Increasing Trend ◽  
Z Value ◽  
Telangana State

Aims: To investigate and assess the significance of the potential trend of two variables viz. rainfall, temperature in Jagtial district of Telangana state. Place and Duration of Study: Data of Daily rainfall and temperature data of 39 years (1980-2019) collected from the meteorological observatory at Regional Agricultural Research Station, Polasa, Jagtial. Methodology: In this study, trend analysis has been carried out on monthly, seasonal and annual basis using the data period between 1980 to 2019 for rainfall and temperature. Mann-Kendall test and Sen’s slope estimate test were applied to identify the existing trend direction and magnitude of change over time. Results: The rainfall seasonal trend analysis indicates that pre-monsoon, monsoon and post-monsoon and winter period showed a negative rainfall trend with z statistics of-1.47, -2.51, -0.55 and-1.38 respectively. However, the annual rainfall showed a negative trend with a z value of -2.53. In the case of Sen’s slope shows that negative trend in monthly, seasonal and annual rainfall.  But the significant rising trend of monthly, seasonal average temperature is noticed from 1980 onwards. The annual average maximum temperature in the Jagtial showed an increasing trend (Z value +5.03). An increasing trend in the all seasons will lead to increase in annual mean temperature. The results of minimum temperature shows a rising trend and falling trend observed Monthly. However annual mean minimum temperature in the Jagtial District showed an increasing trend (Z value 0.10). In the case of maximum temperature for the observed period, it showed rising trend (Sen's slope = 0.63) while the minimum temperature trend showed no trend (Sen's slope = 0.02). Conclusion: Time series was carried out using nonparametric M–K test and Sen's slope estimator, which are widely used tests for conducting trend analysis. Therefore, its take into think about the rainfall variability in particular and temperature variability in general of the area into their climate change adaptation approach.

scholarly journals Rainfall Trend And Seasonality Estimation For Marathwada Region

2021 ◽  
Author(s):  
Himanshu Bana ◽  
R. D Garg
Keyword(s):  
Trend Analysis ◽  
Monsoon Season ◽  
Research Work ◽  
Negative Trend ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Rainfall Trend ◽  
Estimation Process ◽  
Sen’S Slope ◽  
Slope Estimation

Abstract The present research work conducts a seasonality and trend analysis of rainfall over the 8 districts of the Marathwada region India. The study is carried out for the last 39 years ranging from 1980 to 2018. The rainfall data analysed pertains to pre-monsoon season, monsoon season (Kharif), and annual. The trend has been estimated using Sen’s slope estimation process along with Mann-Kendal test. It was observed that the all the Eight districts of the region show a negative trend in the annual rainfall received. Nanded district showed the largest negative trend in the annual rainfall. Out of eight districts seven districts of the region show a decline in rainfall during the monsoon season. The district of Nanded showed largest decline in the rainfall received during monsoon season. The present research work concludes with discussion on possible causes of such estimated trends.

Homogeneity Evaluation of Historical Rainfall and Temperature Series in Mato Grosso

2019 ◽  
pp. 1-7
Author(s):  
Elizangela Selma da Silva ◽  
José Holanda Campelo Júnior ◽  
Francisco De Almeida Lobo ◽  
Ricardo Santos Silva Amorim
Keyword(s):  
Trend Analysis ◽  
Minimum Temperature ◽  
Statistical Tests ◽  
Kendall Test ◽  
Maximum Temperature ◽  
Data Series ◽  
Positive Trend ◽  
Mato Grosso ◽  
Temperature Climate ◽  
Precipitation And Temperature

The homogeneity investigation of a series can be performed through several nonparametric statistical tests, which serve to detect artificial changes or non-homogeneities in climatic variables. The objective of this work was to evaluate two methodologies to verify the homogeneity of the historical climatological series of precipitation and temperature in Mato Grosso state. The series homogeneity evaluation was performed using the following non-parametric tests: Wald-Wolfowitz (for series with one or no interruption), Kruskal-Wallis (for series with two or more interruptions), and Mann-Kendall (for time series trend analysis). The results of the precipitation series homogeneity analysis from the National Waters Agency stations, analyzed by the Kruskal-Wallis and Wald-Wolfowitz tests, presented 61.54% of homogeneous stations, being well distributed throughout Mato Grosso state, whereas those of the trend analysis allowed to identify that 87.57% of the rainfall-gauging stations showed a concentrated positive trend, mainly in the rainy season. Out of the conventional stations of the National Institute of Meteorology of Mato Grosso, seven were homogeneous for the precipitation variable, five for maximum temperature and four stations were homogeneous for minimum temperature. For the trend analysis in the 11 stations, positive trends of random nature were observed, suggesting increasing alterations in the analyzed variables. Therefore, the trend analysis performed by the Mann-Kendall test in the precipitation, and maximum and minimum temperature climate series, indicated that several data series showed increasing trends, suggesting a possible increase in precipitation and temperature values over the years. The results of the Kruskal-Wallis and Wald-Wolfowitz tests for homogeneity presented more than 87% of homogeneous stations.

Analysis of the extreme heat events in Iran

2017 ◽  
Vol 9 (4) ◽  
pp. 418-432 ◽  
Author(s):  
Hojjatollah Yazdanpanah ◽  
Josef Eitzinger ◽  
Marina Baldi
Keyword(s):  
Trend Analysis ◽  
Heat Wave ◽  
Heat Waves ◽  
Temporal Variations ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Positive Trend ◽  
Content Type ◽  
Hot Days

Purpose The purpose of this paper is to assess the spatial and temporal variations of extreme hot days (H*) and heat wave frequencies across Iran. Design/methodology/approach The authors used daily maximum temperature (Tmax) data of 27 synoptic stations in Iran. These data were standardized using the mean and the standard deviation of each day of the year. An extreme hot day was defined when the Z score of daily maximum temperature of that day was equal or more than a given threshold fixed at 1.7, while a heat wave event was considered to occur when the Z score exceeds the threshold for at least three continuous days. According to these criteria, the annual frequency of extreme hot days and the number of heat waves were determined for all stations. Findings The trend analysis of H* shows a positive trend during the past two decades in Iran, with the maximum number of H* (110 cases) observed in 2010. A significant trend of the number of heat waves per year was also detected during 1991-2013 in all the stations. Overall, results indicate that Iran has experienced heat waves in recent years more often than its long-term average. There will be more frequent and intense hot days and heat waves across Iran until 2050, due to estimated increase of mean air temperature between 0.5-1.1 and 0.8-1.6 degree centigrade for Rcp2.6 and Rcp8.8 scenarios, respectively. Originality/value The trend analysis of hot days and heat wave frequencies is a particularly original aspect of this paper. It is very important for policy- and decision-makers especially in agriculture and health sectors of Iran to make some adaptation strategies for future frequent and intense hot days over Iran.

scholarly journals Rainfall trend analysis

2021 ◽  
Vol 17 (1) ◽  
pp. 121-125
Author(s):  
Virendra N. Barai ◽  
Rohini M. Kalunge
Keyword(s):  
Trend Analysis ◽  
Kendall Test ◽  
River Basins ◽  
Annual Rainfall ◽  
Positive Trend ◽  
Rainfall Trend ◽  
Trend Magnitude ◽  
Increasing Trends ◽  
Multiple Units ◽  
Rainy Days

This article aims to review studies pertaining to trends in rainfall, rainy days over India. Non-parametric tests such as Sen’s Slope were used as estimator of trend magnitude which was supported by Mann-Kendall test. The findings of various studies indicate variance with respect to the rainfall rate, which contributes to an uncertain picture of the rainfall trend. In the study of monsoon of different locations in India some places showed increasing trends however, there is signifying decrease in trend all over India. It was also mentioned that analysis can vary from for a location if done using different source or types of collection of data. Spatial units range from station results and sub-division to sub-basin/river basins for trend analysis. The outcomes of the different experiments vary and a simple and reliable picture of the trend of rainfall has not appeared. While there can be a non-zero slope value for the multiple units (sub-basins or sub-divisions), few values are statistically important. In a basin-wise trend analysis report, some basins had a declining annual rainfall trend; at a 95 per cent confidence stage, only one basin showed a strong decreasing trend. Out of the six basins exhibiting a rising trend saw a major positive trend in one basin. Many of the basins have the same pattern direction on the annual and seasonal scale for rainfall and rainy days.

scholarly journals Trend analysis of rainfall using Mann-Kendall, Sen’s slope, moving average and least square techniques for Ahmednagar district of Maharashtra

2021 ◽  
Vol 17 (1) ◽  
pp. 19-25
Author(s):  
Virendra N. Barai ◽  
Rohini M. Kalunge
Keyword(s):  
Time Series ◽  
Trend Analysis ◽  
Moving Average ◽  
Rainfall Variability ◽  
Least Square ◽  
Annual Rainfall ◽  
Series Data ◽  
Sen’S Slope ◽  
Increasing Trend ◽  
The Impact

The long-term behaviour of rainfall is necessary to study over space with different time series viz., annual, monthly and weekly as it is one of the most significant climatic variables. Rainfall trend is an important tool which assesses the impact of climate change and provides direction to cope up with its adverse effects on the agriculture. Several studies have been performed to establish the pattern of rainfall over various time periods for different areas that can be used for better agricultural planning, water supply management, etc. Consequently, the present report, entitled “Trend analysis of rainfall in Ahmednagar district of Maharashtra,” was carried out. 13 tahsils of the district of Ahmednagar were selected to carry out trend analysis. The daily rainfall data of 33 years (1980- 2012) of all stations has been processed out study the rainfall variability. The Mann Kendall (MK) Test, Sen’s slope method, moving average method and least square method were used for analysis. The statistical analysis of whole reference time series data highlighted that July and August month contributes highest amount of rainfall at all tahsils. Regarding trend in annual rainfall, these four methods showed increasing trend at most of the tahsils whereas a decreasing trend only at Shrigonda tahsil. For monthly trend analysis, Kopargaon, Newasa, Shevgaon and Shrirampur tahsils showed an increasing trend during July. During August and September month, most of the tahsils i.e. Kopargaon, Nagar, Parner and Sangamner showed increasing trends, whereas in June, only Shrigonda tahsil showed decreasing trend.

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.

Monotonic Trend Analysis of Temperature Series over Mandya City, Karnataka

2021 ◽  
Vol 9 (VII) ◽  
pp. 1530-1535
Author(s):  
Madhusudhan M S
Keyword(s):  
Climate Change ◽  
Trend Analysis ◽  
Agricultural Sector ◽  
Kendall Test ◽  
Temperature Series ◽  
Maximum Temperature ◽  
Positive Trend ◽  
Significance Level ◽  
Monotonic Trend ◽  
Indirect Impacts

Climate change is mostly driven by global warming. Climate change is one of the most critical long-term development issues, particularly for developing countries like India. India is one of the world's most climatically diverse countries, making it sensitive to climatic change and impacting the livelihoods of millions of people who rely on agriculture. Temperature and its fluctuation have direct and indirect impacts on crop development in the agricultural sector. Understanding the temperature and its variability in a changing environment would aid in improved decision-making and suggest feasible adaption strategies. The present study focuses on temperature trend analysis in Mandya city, Karnataka, India. The analysis was carried out through the non-parametric Mann-Kendall test and Sen's slope estimator. The findings demonstrate that, there has been a rising trend in temperature in the study area over the last 30 years as a result of climate change. From the analysis, there is a significant positive trend for all the seasons considered for the significance level of 90%, 95% and 99%. The magnitude of the increasing trend will be in the range of 0.46 °C/year for the average time series. Also, there will be an average increase of 0.07 °C/year for the various scenarios considered in Mandya city for the Maximum temperature series.

scholarly journals Agricultural community-based impact assessment and farmers’ perception of climate change in selected Ecological Zones in Nigeria

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Isaac Ayo Oluwatimilehin ◽  
Ayansina Ayanlade
Keyword(s):  
Climate Change ◽  
Structured Interview ◽  
Temporal Variations ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Major Barrier ◽  
Ecological Zones ◽  
Sen’S Slope ◽  
Slope Analysis ◽  
Mean Annual Rainfall

Abstract Background The impacts of climate change are affecting sustenance and livelihood of many rural farmers in Africa. The majority of these farmers have low adaptive capacity. This study investigates climate change impacts, farmers’ perception, adaptation options and barriers to adaptation in three selected ecological zones in Nigeria using three staple crops. Rainfall and temperature data of over 35 years were analysed using ANOVA, Mann Kendall and Sen’s Slope Analysis. Farmers’ perception of climate change and cropping experiences were assessed with the aid of a well-structured questionnaire, semi-structured interview and focus group discussion. Results The results of the study revealed high variability in the annual and monthly rainfall and temperature during the study period. The highest annual maximum temperature was recorded in Kwara with Tmax > 32 ℃. Though, there appeared to be spatial and temporal variations in rainfall in the study area, the highest was in Ogun with mean annual rainfall = 1586.9 mm and lowest in Kwara with mean annual rainfall = 1222.6 mm. Generally the Mann Kendall and Sen's slope analysis revealed general increase in the minimum and maximum temperature, while rainfall revealed generally downward trend. The study revealed a difference in farmers’ perception but nearly 74% of farmers perceived that climate is changing, which is affecting their farming activities. Nearly 70% claimed that lack of financial capital is the major barrier to climate change adaptation. Conclusions The study concludes that rainfall and temperature variability have significantly impacted cropping and that farmers are aware of long-term changes in temperature and rainfall, but some are unable to identify those changes as climate change. There is a need for affordable and available improved seedlings and variety of crops that can adapt to climate change conditions.

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