scholarly journals Aspects regarding the trend of the average annual, seasonal and monthly drainage of river water from the Căliman Mountains in the period 1950-2010

2021 ◽  
Vol 28 (1) ◽  
pp. 121-134
Author(s):  
HIRLAV COSTIN
Keyword(s):  
River Water ◽  
Kendall Test ◽  
Nonparametric Method ◽  
Water Drainage ◽  
Change Rate ◽  
Sen’S Slope ◽  
Eastern Carpathians ◽  
Central Strip ◽  
Western Side ◽  
Sen’S Slope Estimates

The Căliman Mountains are the highest volcanic mountains in Romania, being positioned on the western side of the Eastern Carpathians, between their central strip (north and east), south – the Harghita Mountains, and west – the Transylvanian Depression. This positioning gives special features of the water drainage, with both spatial and temporal differentiations. This paper analyzed the trend of average drainage from rivers in the studied group for the period 1950-2010, both multi-annually and seasonally and in the extreme months; the months taken into account being those with the lowest flows (January), respectively the largest (May). To evaluate the mentioned parameters, we used the help of Excel MAKESENS (Mann-Kendall test for trend and Sen’s slope estimates), which identified the type of drainage trend (positive or negative), and using the Sen nonparametric method to estimate the slope of the trend. Based on the type of trend obtained, 9 trend classes were obtained, and with the help of the slope, the net change rate was obtained.

scholarly journals Evapotranspiration Intensification Over Unchanged Temperate Vegetation in the Baltic Countries Is Being Driven by Climate Shifts

2021 ◽  
Vol 4 ◽  
Author(s):  
Bruno Montibeller ◽  
Jaak Jaagus ◽  
Ülo Mander ◽  
Evelyn Uuemaa
Keyword(s):  
Land Cover ◽  
Remote Sensing Data ◽  
Kendall Test ◽  
Rate Of Change ◽  
Sen’S Slope ◽  
Baltic Countries ◽  
Spatiotemporal Trends ◽  
Trade Offs ◽  
The Baltic ◽  
Increasing Trends

Shifts in climate driven by anthropogenic land use and land cover change are expected to alter various land–atmosphere interactions. Evapotranspiration (ET) is one of these processes and plays a fundamental role in the hydrologic cycle. Using gridded reanalysis and remote sensing data, we investigated the spatiotemporal trends of precipitation, temperature, and ET for areas in the Baltic countries Lithuania, Latvia and Estonia where the land cover type had not changed from 2000 to 2018. We focused on ET but investigated the spatiotemporal trends for the three variables at monthly, seasonal, and annual time scales during this period to quantify trade-offs among months and seasons. We used the Mann-Kendall test and Sen’s slope to calculate the trends and rate of change for the three variables. Although precipitation showed fewer statistically significant increasing and decreasing trends due to its high variability, temperature showed only increasing trends. The trends were concentrated in late spring (May, +0.14°C annually), summer (June and August, +0.10°C), and early autumn (September, +0.13°C). For unchanged forest and cropland areas, we found no statistically significant ET trends. However, Sen’s slope indicated increasing ET in April, May, June, and September for forest areas and in May and June for cropland. Our results indicate that during the study period, the temperature changes may have lengthened the growing season, which affected the ET patterns of forest and cropland areas. The results also provide important insights into the regional water balance and complement the findings of other studies.

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 Air Temperature Change in the Southern Tarim River Basin, China, 1964–2011

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Benfu Zhao ◽  
Jianhua Xu ◽  
Zhongsheng Chen ◽  
Ling Bai ◽  
Peng Li
Keyword(s):  
Correlation Analysis ◽  
River Basin ◽  
Air Temperature ◽  
Negative Correlation ◽  
Kendall Test ◽  
Temperature Data ◽  
Tarim River ◽  
Tarim River Basin ◽  
Change Rate ◽  
Mann Kendall Test

The temperature data from 3 meteorological stations (Kashi, Ruoqiang, and Hotan) in the South of Tarim River Basin (STRB) during 1964–2011 were analyzed by Mann-Kendall test and correlation analysis. The results from Mann-Kendall test show that the surface temperature (ST), 850 hPa temperature (T850), and 700 hPa temperature (T700) exhibited upward trends, while 300 hPa temperature (T300) revealed a downward trend. On the whole, the change rate of ST, T850, T700, and T300 was 0.26~0.46°C/10a, 0.15~0.40°C/10a, 0.03~0.10°C/10a, and −0.38~−0.13°C/10a, respectively. For the periods, ST and T850 declined during 1964–1997 and then rose during 1998–2011. T700 declined during 1964–2005 and then rose during 2006–2011, while T300 rose from 1964 to 1970s and then declined. The results from correlation analysis show that T850 and T700 positively correlated with ST (P<0.01) at the all three stations and there was a negative correlation between T300 and ST at Hotan (P<0.1), while the correlation is not significant at Kashi and Ruoqiang. The results indicate that there were gradient differences in the response of upper-air temperature (UT) to ST change.

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 Sea surface temperature trend analysis by Mann-Kendall test and sen’s slope estimator: a study of the Hai Phong coastal area (Vietnam) for the period 1995-2020

2022 ◽  
Author(s):  
Vinh Vu Duy ◽  
Sylvain Ouillon ◽  
Hai Nguyen Minh
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Coastal Area ◽  
Kendall Test ◽  
Sea Surface ◽  
Intrinsic Mode Functions ◽  
Sen’S Slope ◽  
Enso Events ◽  
Mann Kendall Test ◽  
The Impact

Based on the Mann-Kendall test and Sen’s slope method, this study investigates the monthly, seasonal, and annual sea surface temperature (SST) trends in the coastal area of Hai Phong (West of Tonkin Gulf) based on the measurements at Hon Dau Station from 1995 to 2020. The results show a sea surface warming trend of 0.02°C/year for the period 1995-2020 (significant level α = 0.1) and of 0.093°C/year for the period 2008-2020 (significant level α = 0.05). The monthly SSTs in June and September increased by 0.027°C/year and 0.036°C/year, respectively, for the period 1995-2020, and by 0.080°C/year and 0.047°C/year, respectively, for the period 2008-2020. SST trends in winter, summer, and other months were either different for the two periods or not significant enough. This may be due to the impact of ENSO, which caused interannual SST variability in the Hai Phong coastal with two intrinsic mode functions (IMF) signals a period of ~2 (IMF3) and ~5.2 years cycle (IMF4). A combination of these signals had a maximum correlation of 0.22 with ONI (Oceanic Niño Index) delayed by 8 months. ENSO events took ~8 months to affect SST at Hai Phong coastal area for 1995-2020 and caused a variation of SST within 1.2°C.

scholarly journals Effect of climate change and deforestation on vector borne diseases in the North-Eastern Indian state of Mizoram bordering Myanmar

2020 ◽  
Author(s):  
Balasubramani Karuppusamy ◽  
Devojit Kumar Sarma ◽  
Pachuau Lalmalsawma ◽  
Lalfakzuala Pautu ◽  
Krishanpal Karmodiya ◽  
...  
Keyword(s):  
Climate Change ◽  
Minimum Temperature ◽  
Forest Cover ◽  
Kendall Test ◽  
Maximum Temperature ◽  
Monsoon Period ◽  
Vector Borne Diseases ◽  
Sen’S Slope ◽  
Mann Kendall Test ◽  
Vector Borne

Abstract Background Malaria and dengue are the two major vector-borne diseases in Mizoram. Malaria is endemic in Mizoram, and dengue was first reported only in 2012. It is well documented that climate change has a direct influence on the incidence and spread of vector-borne diseases. The study was designed to study the trends and impact of climate variables (temperature, rainfall and humidity) in the monsoon period (May to September) and deforestation on the incidence of dengue and malaria in Mizoram. Methods Temperature, rainfall and humidity data of Mizoram from 1979–2013 were obtained from the National Centers for Environmental Prediction Climate Forecast System Reanalysis and analyzed. Forest cover data of Mizoram was extracted from India State of Forest Report (IFSR) and Land Processes Distributed Active Archive Centre. Percent tree cover datasets of Advanced Very High Resolution Radiometer and Moderate Resolution Imaging Spectroradiometer missions were also used to study the association between deforestation and incidence of vector-borne diseases. The study used non-parametric tests to estimate long-term trends in the climate (temperature, rainfall, humidity) and forest cover variables. The trend and its magnitude are estimated through Mann-Kendall test and Sen's slope method. Year-wise dengue and malaria data were obtained from the State Vector Borne Disease Control Program, Mizoram. Results The Mann-Kendall test indicates that compared to maximum temperature, minimum temperature during the monsoon period is increasing (p < 0.001). The Sen’s slope estimation also shows an average annual 0.020C (0.01–0.03 at 95% CI) monotonic increasing trend of minimum temperature. The residuals of Sen’s estimate show that temperature is increasing at an average of about 0.10C/year after 2007.Trends indicate that both rainfall and humidity are increasing (p <. 0.001); on an average, there is a 20.45 mm increase in monsoon rainfall per year (5.90–34.37 at 95% CI), while there is a 0.08% (0.02–0.18 at 95% CI) increase in relative humidity annually. IFSR data shows that there is an annual average decrease of 162 sq.km (272.81–37.53 at 95% CI, p < 0.001) in the dense forest cover. Mizoram in 2012 was the last state in India to report the incidence of dengue. Malaria transmission continues to be stable in Mizoram; compared to 2007, the cases have increased in 2019. Conclusion Over the study period, there is an ~ 0.80C rise in the minimum temperature in the monsoon season which could have facilitated the establishment of Aedes aegypti, the major dengue vector in Mizoram. In addition, the increase in rainfall and humidity may have also helped the biology of Ae. aegypti. Deforestation could be one of the major factors responsible for the consistently high number of malaria cases in Mizoram.

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.

scholarly journals Long Term Historic Changes in the Flow of Lesser Zab River, Iraq

Hydrology ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 22 ◽  
Author(s):  
Rawshan Ali ◽  
Arez Ismael ◽  
Arien Heryansyah ◽  
Nadeem Nawaz
Keyword(s):  
Climate Change ◽  
Scientific Community ◽  
River Flow ◽  
Kendall Test ◽  
Hydraulic Structures ◽  
Trend Test ◽  
Adaptation Measures ◽  
Sen’S Slope ◽  
Water Scarce

The assessment of trends in river flows has become of interest to the scientific community in order to understand the changing characteristics of flow due to climate change. In this study, the trends in river flow of Dukan Dam located in the northern part of Iraq were assessed. The assessment was carried out for the period 1964 to 2013 using Sen’s slope and the Mann–Kendall test. Sen’s slope was used to assess the magnitude of change while the Mann–Kendall trend test was used to confirm the significance of trends. The results of the study showed that there was a decreasing trend in river flow both annually and for all individual months. The highest decreasing trend of −5.08846 m3/month was noticed in April, while the lowest change of −1.06022 m3/month was noticed in November. The annual flow also showed a significant decrease at a rate of −1.912 m3/year at a 95% level of confidence. Additionally, the findings of the study also confirmed that a decrease in precipitation and the construction of hydraulic structures reduced the flow in the river. The findings of the study suggest that decreasing trends may cause a water-scarce situation in the future if proper adaptation measures are not taken.

scholarly journals The Effect of Irrigative Quality Water by Addition Various Acids of Growth and Wheat Total (Triticum aestivum)

2018 ◽  
Vol 7 (1) ◽  
pp. 128-136
Author(s):  
Evan A. Al-Khafaji
Keyword(s):  
Triticum Aestivum ◽  
Organic Matter ◽  
River Water ◽  
Plant Height ◽  
Drainage Water ◽  
Water Drainage ◽  
Potassium Humate ◽  
Randomized Design ◽  
Biological Yield ◽  
Quality Water

An experiment has been conducted to study the effect of the quality of irrigation water quality and festination with Potassium and KSC in wheat (Triticum aestivum) cv Moelhu growth productivity. Eight treatments were applied ; irrigation with river water , drainage water , river water plus Potassium humate , river water plus KSC , river water plus Potassium humate plus KSC , drainage water plus Potassium humate , drainage water plus KSC , drainage water plus Potassium humate plus KSC . The treatments are put in completely randomized design with three replications . The parameters measured included ; plant height , spike length , total chlorophyll in SPAD , biological yield , grain yield , harwst index and NPK leaves content . The results show outweigh the treatment of river, the added organic matter type Slphoric acid and type Potassium humateas compared with the other proportion like the rate of chlorophyll in the leaves, while not it's significantly different from the treatment by drainage water that added organic matter to both previous properties, but it's significantly different as compared with it by plant height feature . and  the drainage water excelled with added two types of organic matter in the character of the length of the tufts compared with the comparison treatment and treatment of river water that the added matter of both two types of organic material that are used in the experiment.  

scholarly journals Effects of the prewhitening method, the time granularity, and the time segmentation on the Mann–Kendall trend detection and the associated Sen's slope

2020 ◽  
Vol 13 (12) ◽  
pp. 6945-6964
Author(s):  
Martine Collaud Coen ◽  
Elisabeth Andrews ◽  
Alessandro Bigi ◽  
Giovanni Martucci ◽  
Gonzague Romanens ◽  
...  
Keyword(s):  
Time Series ◽  
Trend Analysis ◽  
Statistical Significance ◽  
Parametric Method ◽  
Kendall Test ◽  
Trend Detection ◽  
Temporal Segmentation ◽  
Sen’S Slope ◽  
Power Of The Test ◽  
Original Time

Abstract. The Mann–Kendall test associated with the Sen's slope is a very widely used non-parametric method for trend analysis. It requires serially uncorrelated time series, yet most of the atmospheric processes exhibit positive autocorrelation. Several prewhitening methods have therefore been designed to overcome the presence of lag-1 autocorrelation. These include a prewhitening, a detrending and/or a correction of the detrended slope and the original variance of the time series. The choice of which prewhitening method and temporal segmentation to apply has consequences for the statistical significance, the value of the slope and of the confidence limits. Here, the effects of various prewhitening methods are analyzed for seven time series comprising in situ aerosol measurements (scattering coefficient, absorption coefficient, number concentration and aerosol optical depth), Raman lidar water vapor mixing ratio, as well as tropopause and zero-degree temperature levels measured by radio-sounding. These time series are characterized by a broad variety of distributions, ranges and lag-1 autocorrelation values and vary in length between 10 and 60 years. A common way to work around the autocorrelation problem is to decrease it by averaging the data over longer time intervals than in the original time series. Thus, the second focus of this study evaluates the effect of time granularity on long-term trend analysis. Finally, a new algorithm involving three prewhitening methods is proposed in order to maximize the power of the test, to minimize the number of erroneous detected trends in the absence of a real trend and to ensure the best slope estimate for the considered length of the time series.

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