scholarly journals Long-Term Homogeneity and Trends of Hydroclimatic Variables in Upper Awash River Basin, Ethiopia

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Mekonnen H. Daba ◽  
Gebiaw T. Ayele ◽  
Songcai You
Keyword(s):  
Time Series ◽  
Water Resource ◽  
Addis Ababa ◽  
Annual Rainfall ◽  
Homogeneity Test ◽  
Homogeneity Tests ◽  
Sen’S Slope ◽  
Increasing Trend ◽  
Hydroclimatic Variables

Understanding long-term trends in hydroclimatic variables is important for future sustainable water resource management as it could show the possible regime shifts in hydrology. The main objective of this study was to analyze the homogeneity and trends of hydroclimatic data of Upper Awash Sab-Basin (UASB) in Oromia, Ethiopia, by employing homogeneity tests and Mann-Kendall and Sen’s slope tests. The data consist of 18 rainfall stations, 8 temperature stations, and 8 flow gauging stations across the UASB. Homogeneity and trends in streamflow, rainfall, and temperature variables were analyzed for the time period 1980 to 2017. In order to analyze homogeneity of hydroclimatic variables, we used four homogeneity tests (Pettitt’s test, Buishand’s test, standard normal homogeneity test, and von Neumann ratio test) at 5% significance level. Based on the outputs of four homogeneity tests, the results were classified into three categories, namely, “useful,” “doubtful,” and “suspect” to select the homogeneity stations. Mann-Kendall (Z) and Sen’s slope tests (Q) were applied for the selected homogeneous time series to detect the trend and magnitude of changes in hydroclimatic variables. The result showed that most of the stations in annual rainfall and streamflow data series were classified as useful. It is found that 58% of the rainfall stations were homogeneous. It is highlighted that 3 out of 8 discharge gauging stations have an inhomogeneity as they failed from one or a combination of the four tests. The MK revealed significant decreasing trends of annual rainfall in Addis Alem (Q = −19.81), Akaki (Q = −5.60), Hombole (Q = −9.49), and Ghinch (Q = −12.38) stations. The trend of annual temperature was a significant increasing trend in Addis Ababa Bole (Q = 0.05), Addis Ababa Tikur Ambessa (Q = 0.03), Tulu Bolo (Q = 0.07), and Addis Alem (Q = 0.06) stations. The results of discharge showed a significant increasing trend in Bega at Mojo (Q = 0.17) and Hombole (Q = 0.03) gauging stations. In general, the results obtained from discharge, rainfall, and temperature series indicated that most of the stations exhibited no trends in both annual and seasonal time series. It can be concluded that decreases in average annual rainfall totals and increases in mean annual temperature will probably drive sub-basin scale changes in discharge. We believe that the results obtained can fill information gaps on homogeneity and trends of hydroclimatic variables, which is very crucial for future water resource planning and management in the face of climate change.

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 The effects of carbon emissions, rainfall, temperature, inflation, population, and unemployment on economic growth in Saudi Arabia: An ARDL investigation

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248743
Author(s):  
Md Mazharul Islam ◽  
Majed Alharthi ◽  
Md Wahid Murad
Keyword(s):  
Economic Growth ◽  
Time Series ◽  
Saudi Arabia ◽  
Carbon Emissions ◽  
Annual Rainfall ◽  
Long Term Effects ◽  
Ardl Model ◽  
Long Run ◽  
Unemployment Problem

Objective While macroeconomic and environmental events affect the overall economic performance of nations, there has not been much research on the effects of important macroeconomic and environmental variables and how these can influence progress. Saudi Arabia’s economy relies heavily on its vast reserves of petroleum, natural gas, iron ore, gold, and copper, but its economic growth trajectory has been uneven since the 1990s. This study examines the effects of carbon emissions, rainfall, temperature, inflation, population, and unemployment on economic growth in Saudi Arabia. Methods Annual time series dataset covering the period 1990–2019 has been extracted from the World Bank and General Authority of Meteorology and Environmental Protection, Saudi Arabia. The Autoregressive Distributed Lag (ARDL) approach to cointegration has served to investigate the long-run relationships among the variables. Several time-series diagnostic tests have been conducted on the long-term ARDL model to check its robustness. Results Saudi Arabia can still achieve higher economic growth without effectively addressing its unemployment problem as both the variables are found to be highly significantly but positively cointegrated in the long-run ARDL model. While the variable of carbon emissions demonstrated a negative effect on the nation’s economic growth, the variables of rainfall and temperate were to some extent cointegrated into the nation’s economic growth in negative and positive ways, respectively. Like most other nations the short-run effects of inflation and population on economic growth do vary, but their long-term effects on the same are found to be positive. Conclusions Saudi Arabia can achieve both higher economic growth and lower carbon emissions simultaneously even without effectively addressing the unemployment problem. The nation should utilize modern scientific technologies to annual rainfall losses and to reduce annual temperature in some parts of the country in order to achieve higher economic growth.

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 Modeling and Trend Analysis of Climatic Variables of Ranchi District, Jharkhand

2021 ◽  
Vol 8 (2) ◽  
pp. 120-128
Author(s):  
PAWAN JEET ◽  
KN SINGH ◽  
RAJEEV RANJAN KUMAR ◽  
BISHAL GURANG ◽  
AK SINGH ◽  
...  
Keyword(s):  
Minimum Temperature ◽  
Monsoon Season ◽  
Arima Model ◽  
Climatic Variables ◽  
Annual Rainfall ◽  
Annual Maximum ◽  
Rainfall Trend ◽  
Average Rainfall ◽  
Increasing Trend

In this paper, an attempt has been made to study the temporal variation in monthly, seasonal and annual rainfall, and average annual maximum and minimum temperature for the period 1901-2015 over Ranchi district of Jharkhand, India. Long-term changes in rainfall, temperature was determined by Man-Kendall rank statistics and Sen’s slope, and forecasting of time series was determined by ARIMA model. The results revealed that there was significant decrease of average rainfall in the month of February and August while increase in month May and Pre-monsoon season. Average rainfall in the month of February, May, August and Pre-monsoon season showing insignificant increasing as well as decreasing rainfall trend. The average annual maximum and minimum temperature showing decreasing and increasing trend over Ranchi district during the period 1901 to 2015. This paper also describes five-year prediction of rainfall and temperature climatic variables.

scholarly journals Homogenization of Portuguese long-term temperature data series: Lisbon, Coimbra and Porto

2012 ◽  
Vol 5 (2) ◽  
pp. 521-584 ◽  
Author(s):  
A. L. Morozova ◽  
M. A. Valente
Keyword(s):  
Climate Variability ◽  
Volcanic Eruptions ◽  
Temperature Data ◽  
Temperature Series ◽  
Data Series ◽  
Homogeneity Test ◽  
Homogeneity Tests ◽  
Future Studies ◽  
Standard Normal Homogeneity Test

Abstract. Three long-term temperature data series measured in Portugal were studied to detect and correct non-climatic homogeneity breaks and are now available for future studies of climate variability. Series of monthly minimum (Tmin) and maximum (Tmax) temperatures measured in the three Portuguese meteorological stations of Lisbon (from 1856 to 2008), Coimbra (from 1865 to 2005) and Porto (from 1888 to 2001) were studied to detect and correct non-climatic homogeneity breaks. These series together with monthly series of average temperature (Taver) and temperature range (DTR) derived from them were tested in order to detect homogeneity breaks, using, firstly, metadata, secondly, a visual analysis and, thirdly, four widely used homogeneity tests: von Neumann ratio test, Buishand test, standard normal homogeneity test and Pettitt test. The homogeneity tests were used in absolute (using temperature series themselves) and relative (using sea-surface temperature anomalies series obtained from HadISST2 close to the Portuguese coast or already corrected temperature series as reference series) modes. We considered the Tmin, Tmax and DTR series as most informative for the detection of homogeneity breaks due to the fact that Tmin and Tmax could respond differently to changes in position of a thermometer or other changes in the instrument's environment; Taver series have been used, mainly, as control. The homogeneity tests show strong inhomogeneity of the original data series, which could have both internal climatic and non-climatic origins. Homogeneity breaks which have been identified by the last three mentioned homogeneity tests were compared with available metadata containing data, such as instrument changes, changes in station location and environment, observing procedures, etc. Significant homogeneity breaks (significance 95% or more) that coincide with known dates of instrumental changes have been corrected using standard procedures. It was also noted that some significant homogeneity breaks, which could not be connected to the known dates of any changes in the park of instruments or stations location and environment, could be caused by large volcanic eruptions. The corrected series were again tested for homogeneity: the corrected series were considered free of non-climatic breaks when the tests of most of monthly series showed no significant (significance 95% or more) homogeneity breaks that coincide with dates of known instrument changes. Corrected series are now available in the frame of ERA-CLIM FP7 project for future studies of climate variability (http://doi.pangaea.de/10.1594/PANGAEA.785377).

scholarly journals Spatio -Temporal Long-Term Variability and Trend Analysis of Precipitation and Temperature Series in the Ghataprabha (K3) Sub basin of Krishna Basin

2019 ◽  
Vol 8 (11) ◽  
pp. 2547-2552
Keyword(s):  
India Meteorological Department ◽  
Well Being ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Study Region ◽  
Changing Climate ◽  
Increasing Trend ◽  
Precipitation And Temperature ◽  
Krishna Basin

Changing Climate is one of the most significant ecological issue, with the implications for agricultural production, water resource, energy and some other aspects of human well-being. Analysis of changing climate is important to assess climate-induced changes through the analysis of variability of climatic parameters such as temperature, precipitation, runoff and groundwater to suggest feasible adaptation strategies. This paper aims the long-term variability of rainfall and temperature using gridded daily data obtained from India Meteorological Department with 0.250 resolution from 1901-2016 for precipitation and 10 resolution from 1969-2005 for temperature (re-gridded to IMD 0.250 gridded location) in Ghataprabha sub basin (K3) of Krishna basin. The analysis of variability and trend in precipitation and temperature carried out by using coefficient of variation (CV), rainfall and temperature anomaly and also Mann-Kendall (MK) test was used to detect the time series trend. Statistical analysis of variability and trend in annual, Indian Summer Monsoon (ISMR) rainfall and temperature observed that i) there is an intra and inter annual variability of precipitation in the sub basin ii) test results revealed that the annual and ISMR trend appears to be increased by 0.12 & 0.14, iii) the Mann-Kendal trend test also analysed for annual minimum, mean and maximum temperature over the K3 sub basin (1969-2005) shows increasing trend by 0.06, 0.21 and 0.40. This analysis revealed that, there is an increasing trend in annual rainfall and temperature observed over the study region.

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 Analyzing Trend and Variability of Rainfall in The Tafna Basin (Northwestern Algeria)

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 347 ◽  
Author(s):  
Hanane Bougara ◽  
Kamila Baba Hamed ◽  
Christian Borgemeister ◽  
Bernhard Tischbein ◽  
Navneet Kumar
Keyword(s):  
Time Series ◽  
Water Resource Management ◽  
Statistical Tests ◽  
Trend Detection ◽  
Detection Methods ◽  
Annual Rainfall ◽  
Rainfall Time Series ◽  
Friedman Test ◽  
Upward Trend ◽  
Increasing Trend

Northwest Algeria has experienced fluctuations in rainfall between the two decades 1940s and 1990s from positive to negative anomalies, which reflected a significant decline in rainfall during the mid-1970s. Therefore, further analyzing rainfall in this region is required for improving the strategies on water resource management. In this study, we complement previous studies by dealing with sub basins that were not previously addressed in Tafna basin (our study area located in Northwest Algeria), and by including additional statistical methods (Kruskal–Wallis test, Jonckheere-Terpstra test, and the Friedman test) that were not earlier reported on the large scale (Northwest Algeria). In order to analyse the homogeneity, trends, and stationarity in rainfall time series for nine rainfall stations over the period 1979–2011, we have used several statistical tests. The results showed an increasing trend for annual rainfall after the break detected in 2007 for Djbel Chouachi, Ouled Mimoun, Sidi Benkhala stations using Hubert, Pettitt, and Buishand tests. The Lee and Heghinian test has detected a break at the same year in 2007 for all stations except Sebdou, Beni Bahdel, and Hennaya stations, which have a break date in 1980. We have confirmed this increasing trend for rainfall with other trend detection methods such as Mann Kendall and Sen’s method that highlighted an upward trend for all the stations in the autumn season, which is mainly due to an increase in rainfall in September and October. On a monthly scale, the date of rupture is different from one station to another because the time series are not homogeneous. In addition, we have applied three tests enabling further results: (i) the Jonckheere-Terpstra test has detected an upward trend for two stations (Khemis and Hennaya), (ii) Friedman test has indicated the difference between the mean rank again with Khemis and Hennaya stations and the Merbeh station, (iii) according to the Kruskal-Wallis test, there have been no variance detected between all the rainfall stations. The increasing trend in rainfall may lead to a rise in stream flow and enhance potential floods risks in low-lying regions of the study area.

scholarly journals Needle traces as indicators of growing conditions in Scots pine (Pinus sylvestris L.)

2012 ◽  
Vol 49 (No. 1) ◽  
pp. 1-10 ◽  
Author(s):  
B. Konôpka
Keyword(s):  
Air Pollution ◽  
Time Series ◽  
Pinus Sylvestris ◽  
Forest Stand ◽  
Needle Retention ◽  
Increasing Trend ◽  
Forest Regions ◽  
Needle Trace Method ◽  
Growing Conditions

Needle retention (number of needle sets) and needle density (number of needle pairs per centimeter of shoot) were surveyed on Scots pines in five forest regions of Slovakia. The Needle Trace Method (NTM) was used to determine needle retention and needle density along the main stem retrospectively for the last four decades. In all forest regions, the values of these indicators varied from year to year. However, in Záhorská lowland, Vtáčnik, Krupinská plain, and High Tatras, the trends of both observed indicators were constant over the time series. The situation was different in the Levočské hills, where the needle retention displayed a decreasing trend and needle density an increasing trend. These trends probably reflected a long-term stress of air pollution on pines in this forest stand.

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