scholarly journals Variability and Trend Analysis of Temperature, Rainfall and Characteristics of Crop Growth Season in Eastern Zone of Tigray Region, Northern Ethiopia

2021 ◽  
Author(s):  
Amdom Gebremedhin Berhe ◽  
Solomon Habtu Misgna ◽  
Girmay Gebre-Samuel Abraha ◽  
Amanuel Zenebe Abraha
Keyword(s):  
Trend Analysis ◽  
Rainy Season ◽  
General Trend ◽  
Crop Growth ◽  
Growth Season ◽  
Tigray Region ◽  
Eastern Zone ◽  
Dry Spell ◽  
Increasing Trend ◽  
Spell Length

Abstract To favour farmers and adjusting their farming practices, long term weather analyses is essential to determine future directions and making adjustments required to existing systems. The main purpose of this study was thus to analyze the variability and trends of climatic variables (temperature and rainfall) and characteristics of crop growth season in Eastern zone of Tigray region for the period of 1980–2009. Detail investigations were carried out using parametric (Linear regression) and non-parametric tests (Mankendall and Sen’s slope estimator). Moreover, homogeneity test was applied using a method developed by Van Belle and Hughes for the general trend analysis. Furthermore, the trend of rainfall end to characterize crop growth season using R-Instat and XLSTAT software. It was found that the general trend of monthly rainfall experienced an overall significant increasing trend. The seasonal rainfall experienced significantly increasing trend during the summer rainy season (June–September) whilst a significant decreasing trend occurred in the short rainy season (February–May). Likewise, the seasonal maximum temperature trends exhibited a significant increasing trend in all seasons whereas the minimum temperature showed inhomogeneous trend across seasons as well as stations. Despite significant increase of rainfall in summer season, the trend of growing season characteristics (onset, cessation, length of growing period and dry spell length) did not change significantly over the study period. However, the variability of rainfall and dry spell length was found to be very large. Hence, crop production in the study area demands appropriate adaptation strategies that considers the erratic nature of the rainfall, the long dry spell length in the season and increasing trends of temperature.

scholarly journals Variability and Trend Analysis of Temperature, Rainfall and Characteristics of Crop Growth Season in Eastern Zone of Tigray Region, Northern Ethiopia

2021 ◽  
Author(s):  
Amdom Gebremedhin Berhe ◽  
Solomon Habtu Misgna ◽  
Girmay Gebre-Samuel Abraha ◽  
Amanuel Zenebe Abraha
Keyword(s):  
Trend Analysis ◽  
Minimum Temperature ◽  
Rainy Season ◽  
General Trend ◽  
Crop Growth ◽  
Growth Season ◽  
Tigray Region ◽  
Eastern Zone ◽  
Dry Spell ◽  
Spell Length

Abstract Background: Long term weather analyses are very useful indicators in determining future directions and in making adjustments required to existing systems. And, in order to favor farmers to adjust their farming practices, seasonal climate outlooks are needed. The main purpose of this manuscript was thus to analyze the variability and trends of maximum and minimum temperature, monthly and seasonal rainfall series and characteristics of crop growth season in Eastern zone of Tigray region over the period of 1980–2009.Methods: Detail investigations were carried out using parametric (Linear regression) and nonparametric tests (Mankendall (Mk) and Sen’s slope estimator). Moreover, homogeneity test using a method developed by Van Belle and Hughes was used for general trend analysis. In addition, daily rainfall data to characterize crop growth season were analysed using R-Instat and XLSTAT software for trend analysis.Results: It was found that the general trend of monthly rainfall experienced an overall significant increasing trend. The seasonal rainfall experienced significantly increasing in summer main rainy season, June–September (Kiremt) while significantly decreasing in short rainy season, February– May (Belg). Likewise, the seasonal maximum temperature trends exhibited significant increase in each season while minimum temperature trend had inhomogeneous trend across seasons as well as stations. The trend of growing season characteristics (onset, cessation, LGP and dry spell length did not change significantly over the study period (1980–2009) in all stations. However, the coefficient of variability of LGP was (CV, >15%) and dry spell length was (CV, >25%) inassociation with short nature of LGP (68–85 days had a negative impact on the agricultural activities of the study area during the study period.Conclusions: Despite significant increase of rainfall in summer season, the variability of rainfall and dry spell length was very large. Hence, the study recommends crop production in the study area demands appropriate adaptation strategies that considers the erratic nature of the rainfall, the long dry spell length in the season and increasing trends of temperature.

scholarly journals Statistical Assessment of Rainfall Characteristics in Upper Blue Nile Basin over the Period from 1953 to 2014

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 468 ◽  
Author(s):  
Abeer Samy ◽  
Mona G. Ibrahim ◽  
Wael Elham Mahmod ◽  
Manabu Fujii ◽  
Amr Eltawil ◽  
...  
Keyword(s):  
Trend Analysis ◽  
Rainy Season ◽  
Prediction Models ◽  
Annual Rainfall ◽  
Nile Basin ◽  
Rainfall Distribution ◽  
Blue Nile ◽  
Blue Nile Basin ◽  
Increasing Trend ◽  
Upper Blue Nile Basin

Investigating the trends of hydro-meteorological variables and checking its variability are of great importance for water resources management and development in the River Nile basin. The present study aimed to analyze the rainfall variability and trends in the Upper Blue Nile Basin (UBNB) over a period from 1953 to 2014. Variability analysis showed that the basin has been suffering from variable rainfall events causing severe droughts and floods over different years. According to precipitation concentration index calculations, the basin had irregular and strong irregular rainfall distribution over the annual and dry seasons, while the basin had a uniform and moderate rainfall distribution during the rainy season and small rainy season. For the total annual rainfall, Mann–Kendall test indicated that, for the eastern central part of the basin, a significant increasing trend of 12.85 mm/year occurred over the studied period, while, for the southwestern part of the basin, a significant decrease of 17.78 mm/year occurred. For the rainy season, a significant increasing trend over the northeastern and eastern central parts of the basin with the magnitude of 3.330–12.625 mm/year occurred. Trend analysis was applied on the monthly averaged rainfall over the whole basin and revealed that July and August are the most contributors of rainfall to the basin with 23.32% and 22.65%. Changing point assessment revealed that at Lake Tana outlet there is a decreasing of the rainfall of 17.7% after 1977 that matched with the trend analysis results. The data and results contained herein provide updated information about the current situation in the UBNB. The results can be used to predict future precipitation and estimate the uncertainty in future precipitation prediction models.

Changes in tobacco depictions after implementation of tobacco-free film and TV rules in Bollywood films in India: a trend analysis

2021 ◽  
pp. tobaccocontrol-2021-056629
Author(s):  
Gaurang P Nazar ◽  
Monika Arora ◽  
Nitika Sharma ◽  
Surbhi Shrivastava ◽  
Tina Rawal ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Trend Analysis ◽  
Poisson Regression ◽  
Poisson Regression Analysis ◽  
Free Film ◽  
Rule Compliance ◽  
Increasing Trend ◽  
Before And After ◽  
Year 2013

BackgroundIndia’s tobacco-free film and TV rules were implemented from 2012. To assess the effect of the rules, we studied tobacco depictions in top-grossing Bollywood films released between 2006 and 2017 and rule compliance after 2012.MethodsTobacco incidents and brand appearances were coded in 240 top-grossing Bollywood films (2006–2017) using the Breathe California method. Trends in number of tobacco incidents per film per year were studied before and after implementation of the rules using Poisson regression analysis. Compliance with rules over the years was studied using Pearson product-moment correlations.ResultsForty-five films were U-rated (all ages), 162 were UA-rated (below age 12 years must be adult-accompanied), and 33 were A-rated (age 18+ years only). Before implementation of the rules, the number of tobacco incidents per film was increasing by a factor of 1.1/year (95% CI 1.0 to 1.2, p=0.002). However, beginning year 2013, the number of incidents per film started falling significantly by a factor of 0.7/year (95% CI 0.6 to 0.9; p=0.012) compared with the previous increasing trend. The percentage of youth-rated (U and UA) films with any tobacco incidents also declined from a peak of 76% in 2012 to 35% in 2017. The percentage of films complying with the rules (audio-visual disclaimers, health spots, static warnings) did not change significantly from 2012 to 2017.ConclusionIndia’s 2012 rules were followed by a reduction in tobacco depictions in Bollywood films. Enhanced monitoring of compliance is needed to ensure the continued effectiveness of the rules.

scholarly journals Hydrochemical Evolution in Ciliwung River – Java, Indonesia: Study of Sea Water Mixture and Mineral Dissolution

2020 ◽  
Vol 20 (6) ◽  
pp. 1360
Author(s):  
Evarista Ristin Pujiindiyati ◽  
Paston Sidauruk ◽  
Tantowi Eko Prayogi ◽  
Faizal Abdillah
Keyword(s):  
River Water ◽  
Rainy Season ◽  
Sea Water ◽  
Dry Season ◽  
Mineral Dissolution ◽  
Water Type ◽  
Water Mixture ◽  
Hydrochemical Evolution ◽  
Increasing Trend ◽  
Saturation Indexes

The chemical characteristics of the Ciliwung River were analyzed to understand hydrochemical evolution. A fraction of sea water mixture and kinds of mineral controlling for chemicals were also determined. During three year investigations in 2015, 2016, and 2018, electrical conductivity increased with decreasing elevations. Two hydrochemical facies had been identified for the Ciliwung river water; those were Ca-Mg-HCO3 and Ca-Na-HCO3.  The river water mixing with seawater was recognized in the Mangga Dua site in which its water type had shifted to Na-Ca-HCO3-Cl. Based on Na-Cl contents, the fraction of sea water into the Ciliwung River reached 2% in the Mangga Dua site during the dry season and decreased to 0.7% during the rainy season in 2015. The much higher monthly rainfall during the dry season in 2016 and 2018 had washed out invading seawater from the Mangga Dua site; its fraction of sea water was less than 0.4%. Saturation indexes with respect to calcite, dolomite, and gypsum minerals showed an increasing trend related to the decreasing elevations. All water samples were undersaturated with respect to gypsum. Meanwhile, saturation indexes with respect to calcite and dolomite mostly indicated undersaturated, except in the Mangga Dua site that was saturated (during the rainy season in 2015 and dry season in 2018) and supersaturated during the dry season in 2015.

Temporal Changes in Flow Regime along the River Vistula

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2840
Author(s):  
Ewa Bogdanowicz ◽  
Emilia Karamuz ◽  
Renata Julita Romanowicz
Keyword(s):  
Flow Regime ◽  
Winter Season ◽  
Hydrological Regime ◽  
Mean Value ◽  
Social Perceptions ◽  
Annual Data ◽  
Spatial Changes ◽  
Precipitation Characteristics ◽  
Dry Spell ◽  
Spell Length

The flow regime in the River Vistula is influenced by climatic and geographical factors and human intervention. In this study, we focus on an analysis of flow and precipitation variability over time and space following the course of the River Vistula. Multi-purpose statistical analyses of a number of runoff and precipitation characteristics were performed to present a general overview of the temporal and spatial changes. Since the important feature of the hydrological regime of Polish rivers is the seasonality of runoff associated with the occurrence of cold (winter) and warm (summer) seasons within a hydrological year, a seasonal approach is applied to describe specific seasonal features that can be masked when using annual data. In general, the results confirm popular impressions about changes in winter season runoff characteristics, i.e., significantly decreasing daily maxima, increasing daily minima and a decrease in concentration, and so a bigger uniformity of winter daily flows. An interesting behaviour of minimum flows in the summer has been revealed, which is contrary to social perceptions and the alarming changes taking place in the other parts of the world. Additionally, precipitation indexes related to the formation of droughts show no trends, e.g., the mean value of the maximum dry spell length.

scholarly journals Long-Term Trends and Seasonality Detection of the Observed Flow in Yangtze River Using Mann-Kendall and Sen’s Innovative Trend Method

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1855 ◽  
Author(s):  
Ali ◽  
Kuriqi ◽  
Abubaker ◽  
Kisi
Keyword(s):  
Trend Analysis ◽  
Yangtze River ◽  
Winter Season ◽  
Trend Test ◽  
Analysis Method ◽  
Adaptation Measures ◽  
Minimum Flow ◽  
Mk Test ◽  
Innovative Trend Analysis ◽  
Increasing Trend

Trend analysis of streamflow provides practical information for better management of water resources on the eve of climate change. Thus, the objective of this study is to evaluate the presence of possible trends in the annual, seasonal, maximum, and minimum flow of Yangtze River at Cuntan and Zhutuo stations in China for the period 1980 to 2015. The assessment was carried out using the Mann–Kendall trend test, and the innovative trend analysis, while Sen’s slope is used to estimate the magnitude of the changes. The results of the study revealed that there were increasing and decreasing trends at Cuntan and Zhutuo stations in different months. The mean annual flow was found to decrease at a rate of −26.76 m3/s and −17.37 m3/s at both stations. The minimum flow was found to significantly increase at a rate of 30.57 m3/s and 16.37 m3/s, at a 95% level of confidence. Maximum annual flows showed an increasing trend in both regions of the Yangtze River. On the seasonal scale, the results showed that stations are more sensitive to seasonal flow variability suggesting a probable flooding aggravation. The winter season showed an increasing flow trend, while summer showed a decreasing trend. The spring flow was found to have an increasing trend by the Mann–Kendall test at both stations, but in the Zhutuo Station, a decreasing trend was found by way of the innovative trend analysis method. However, the autumn flow indicated a decreasing trend over the region by the Mann–Kendall (MK) test at both stations while it had an increasing trend in Cuntan by the innovative trend analysis method. The result showed nonstationary increasing and decreasing flow trends over the region. Innovative trend analysis method has the advantage of detecting the sub-trends in the flow time series because of its ability to present the results in graphical format. The results of the study indicate that decreasing trends may create water scarcity if proper adaptation measures are not taken.

scholarly journals Assessing baseflow index vulnerability to variation in dry spell length for a range of catchment and climate properties

2018 ◽  
Vol 32 (16) ◽  
pp. 2496-2509 ◽  
Author(s):  
Antonia Longobardi ◽  
Anne Frederike Van Loon
Keyword(s):  
Dry Spell ◽  
Spell Length

Projected changes in extreme precipitation intensity and dry spell length in Côte d’Ivoire under future climates

2020 ◽  
Vol 140 (3-4) ◽  
pp. 871-889 ◽  
Author(s):  
Assi Louis Martial Yapo ◽  
Adama Diawara ◽  
Benjamin K. Kouassi ◽  
Fidèle Yoroba ◽  
Mouhamadou Bamba Sylla ◽  
...  
Keyword(s):  
Cote D'ivoire ◽  
Extreme Precipitation ◽  
Côte D’Ivoire ◽  
Precipitation Intensity ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Dry Spell ◽  
Projected Changes ◽  
Spell Length

Analysis of Agricultural Droughts According to the 2018 Heat Wave in Korea

2020 ◽  
Author(s):  
Hyung Jin Shin ◽  
Jong Won Do ◽  
Jae Nam Lee ◽  
Gyumin Lee ◽  
Mun Sung Kang
Keyword(s):  
Frequency Analysis ◽  
Rainy Season ◽  
Crop Growth ◽  
Agricultural Drought ◽  
Maximum Temperature ◽  
Drought Frequency ◽  
Field Crops ◽  
Drought Frequency Analysis ◽  
Frequency Area ◽  
Cumulative Precipitation

<p><span>According to the Korea Meteorological Administration, in 2018, Korea's national average temperature and maximum temperature are the highest in 111 years since meteorological observations (1907.10.1.) The highest value was observed since August 1 at </span><span> 39.6 </span>℃ <span>in Seoul. Heatwaves represent the number of days with the highest daily temperature above 33 ° C. The number of heatwaves in 18 years totaled 31.5 days. Heatwaves have a particularly significant effect on the growth and death of field crops. Indeed, 18,254 ha of field crops occurred nationwide. Precipitation in 2018 is higher than normal, but precipitation shortages have occurred due to seasonal and regional variations and local droughts due to the lowest precipitation from mid-July to late August. In particular, there were more rains than normal years at the beginning of farming season (March-May) and the end of farming season (October), but the summer agricultural drought occurred due to less precipitation than the average year-end of July-August. The second shortest rainy season (half of the average year) since 1987 and the rainy season was 72% compared to the average year, some of the reservoirs have caused a serious and severe stage. The country recorded the maximum number of rainfall days on 27th during the period of 7.10 ~ 8.5 days and 43 days on Chungnam. This is believed to have affected the drought occurrence by overlapping with the stage of water-forming, which requires the largest amount of water supply for rice growth. In the case of field crops, irrigation facilities are inferior to paddy fields, so field crop growth is directly related to no rainfall days, and droughts such as deterioration of field crops were recorded nationwide during the maximum rainfall period. Since the end of the rainy season, there have been a total of 22,767 ha droughts, iincluding 2,513 ha of paddy field and 20,254 ha of field crops, due to severe shortages of precipitation and damage to crops caused by heat waves. </span><span>For the 2018 rainfall-based drought frequency analysis, the analysis was based on cumulative precipitation from January to August of 18, and there was a severe shortage of precipitation from mid-July to mid-August, but the cumulative precipitation from January to August is normal. As a result of rainfall-based drought frequency analysis, the drought frequency area was analyzed into two regions for more than 10 years. Based on rainfall in July 2018, drought occurred in most parts of the country due to severe rainfall shortages. For over 200 years, the frequency of drought has been analyzed to 107 counties. As a result of the drought frequency analysis based on the reservoir storage rate in August 2018, there were 45 counties in the drought frequency area for more than 200 years due to the lack of water during the high demand period of rice crop growth period.</span></p><div data-hjsonver="1.0" data-jsonlen="11062"><span>This research was supported by a grant(2019-MOIS31-010) from Fundamental Technology Development Program for Extreme Disaster Response funded by Korean Ministry of Interior and Safety(MOIS).</span></div>

scholarly journals Global Trends in the Occurrence and Characteristics of Blocking Anticylones Using Sen Innovative Trend Analysis

2021 ◽  
Vol 8 (1) ◽  
pp. 41
Author(s):  
Bahtiyar Efe ◽  
Anthony R. Lupo
Keyword(s):  
Trend Analysis ◽  
Pacific Region ◽  
Atmospheric Blocking ◽  
University Of Missouri ◽  
Global Trends ◽  
Innovative Trend Analysis ◽  
Increasing Trend ◽  
The University ◽  
Increasing Trends ◽  
High Cluster

Atmospheric blocking plays an important role in modulating mid-latitude weather, in particular in the Northern Hemisphere (NH). Trend analysis of atmospheric blocking for both hemispheres by using Şen’s Innovative Trend Analysis (ITA) is performed in this study. The blocking data archived in the University of Missouri covers the period of 1968–2019 for the NH and 1970–2019 for the Southern Hemisphere is used in the study. Block occurrence, duration and blocking intensity (BI) is analysed by classifying the NH (and SH) into three groups according to the preferred blocking locations: Atlantic, Pacific and Continental (Atlantic, Pacific and Indian). In the NH, blocking intensity showed mixed results. It showed a decreasing trend for the entire hemisphere and Atlantic Region, whilst a different trend was shown for different BI clusters. For blocking numbers and duration, the entire hemisphere and regions showed increasing trends. These increasing trend values were also statistically significant. In the SH, blocking intensity showed a decreasing trend for low clusters, whilst medium and high cluster increased for the entire hemisphere. Block duration showed an increasing trend for the entire SH. Block numbers showed increasing trends, except for one point in the low cluster. Blocking characteristics showed different trends for different preferred blocking locations. Increasing trends of blocking numbers for the overall SH and Pacific region are statistically significant at 95% level. Increasing trends of blocking duration for the overall SH, Atlantic and Pacific region are statistically significant at 90%, 95% and 95% level, respectively.

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