scholarly journals Analysis of Non-Parametric Trend and Climatic Parameter Homogeneity Tests in a Data-scarce Region: A Spatio-Temporal Perspective in the Tawang River Basin, Eastern Himalayas

2021 ◽  
Author(s):  
Juna Probha Devi ◽  
Chandan Mahanta ◽  
Anamika Barua
Keyword(s):  
Water Resource Management ◽  
Management Strategies ◽  
Kendall Test ◽  
Climate Impact ◽  
Mean Annual Precipitation ◽  
Homogeneity Test ◽  
Eastern Region ◽  
Positive Trend ◽  
Temporal Perspective ◽  
Spatio Temporal

Abstract This study is aimed at studying long–term historical and future (1950-2099) trends for the RCP 4.5 and RCP 8.5 on approximately 30-year timescale at annual and seasonal for precipitation and at annual, seasonal, monthly, and diurnal temperature range (DTR) for temperature maximum (T_max), temperature minimum (T_min) variations using statistical trend analysis techniques– Mann–Kendall test (MK) and Sen's slope estimator (S) and the homogeneity test using Pettitt’s test. The study is carried out in three spatial points across the Tawang Chu in the district of Tawang, Arunachal Pradesh. The summer mean precipitation for RCP 4.5 (2006-2065) shows a positive trend with a rise in precipitation between 1.56 mm to 9.94 mm in all the study points. The mean annual precipitation statistics for all the points show an increase of RCP 4.5 in 2006-2052 and 2053-2099 timescale. Both RCP 4.5 and 8.5 scenarios exhibit a uniform rise in T_min and T_max during investigation. For all the points, the results likewise reveal a rising trend in mean annual T_min and T_max. Still, the inter-decadal temperature statistical analysis shows that the increase in mean annual T_min is greater than the increase in T_max, indicating a decreasing trend in DTR. It is anticipated that this study's outcomes will contribute to a better understanding of the relationship between change in climate and the regional hydrological behaviour and will be benefitting the society to develop a regional strategy for water resource management, can serve as a resource for climate impact research scope- assessments, adaptation, mitigation, and disaster management strategies for India's north-eastern region.

scholarly journals Spatio-Temporal Trend Mapping of Precipitation and its Extremes Across Afghanistan (1951-2010)

2021 ◽  
Author(s):  
Quarban Aliyar ◽  
Santosh Dhungana ◽  
Sangam Shrestha
Keyword(s):  
Crop Production ◽  
Heavy Precipitation ◽  
Kendall Test ◽  
Eastern Region ◽  
Spring Precipitation ◽  
Significance Level ◽  
Northeastern Region ◽  
Spatio Temporal ◽  
Slope Estimator ◽  
Harsh Climate

Abstract The civil war, harsh climate, tough topography and lack of accurate meteorological stations has limited observed data across Afghanistan. In order to fulfill the gap, this study analyzed the trend in precipitation and its extremes using Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation (APHRODITE) daily dataset between 1951 to 2010 at the spatial resolution of 0.25˚˟0.25˚. Non-parametric modified Mann-Kendall test and Sen’s slope estimator were employed to detect trend and quantify it at the significance level of 5%. Significant decreasing trends were observed only in small clusters of southwestern regions ranging between 0 to -1.5mm/year and northeastern region between -1.5 to -6 mm/year for the annual time series. Similar trend pattern was observed in spring season decreasing at the rate of -0.15 to 0.54 mm/year in northeastern and 0 to -0.15 mm/year southwestern region. Decrease in spring precipitation is expected to affect crop production especially in northeastern region which host 22 % of the arable area. Increasing trend in eastern region at maximum of 0.16 mm/year was observed which could intensify the flooding events. Trend analysis of extreme precipitation indices indicated similar spatial distribution to the mean precipitation, concentrated around southwestern, northeastern, and eastern regions. Increasing frequency of consecutive dry days in western region and very heavy precipitation (R10mm) and extremely heavy precipitation (R20mm) in eastern region are fueling the occurrence of droughts and floods respectively. Taking these findings of erratic nature of rainfall and extreme events into consideration for sustainable management of water resources would be fruitful.

scholarly journals Regional Response to Global Warming: Water Temperature Trends in Semi-Natural Mountain River Systems

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 283 ◽  
Author(s):  
Mariola Kędra
Keyword(s):  
Water Temperature ◽  
Water Resource Management ◽  
River Flow ◽  
Heat Waves ◽  
Management Strategies ◽  
Thermal Conditions ◽  
Kendall Test ◽  
Mountain River ◽  
River Systems ◽  
Temperature Trends

River water temperature (TW) is a key environmental factor that determines the quality of the fluvial environment and its suitability for aquatic organisms. Atmospheric warming, accompanied by more frequent extreme weather phenomena, especially heat waves and prolonged drought, may pose a serious threat to the river environment and native river ecosystems. Therefore, reliable and up-to-date information on current and anticipated changes in river flow and thermal conditions is necessary for adaptive water resource management and planning. This study focuses on semi-natural mountain river systems to reliably assess the magnitude of water temperature change in the Polish Carpathians in response to climatic warming. The Mann–Kendall test was used to detect trends in water temperature series covering the last 35 years (1984–2018). Significant, rising trends in annual water temperature were found for all studied sites, with differences in intensity (0.33–0.92 °C per decade). Trends in TW were strongest in summer and autumn (0.75–1.17 and 0.51–1.08 °C per decade), strong trends were found in spring (0.82–0.95 °C per decade), and weaker in winter (0.25–0.29 °C per decade). Simultaneous air temperature trends were broadly consistent with water temperature trends. This indicates the urgent need for adaptive management strategies to counteract thermal degradation of the fluvial environment under study.

scholarly journals Spatio-Temporal Analysis of Drought Indicated by SPEI over Northeastern China

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 908 ◽  
Author(s):  
Lei Ye ◽  
Ke Shi ◽  
Hairong Zhang ◽  
Zhuohang Xin ◽  
Jing Hu ◽  
...  
Keyword(s):  
Water Resource Management ◽  
Kendall Test ◽  
Temporal Analysis ◽  
Northeastern China ◽  
Jilin Province ◽  
Liaoning Province ◽  
Songhua River ◽  
Liaohe River ◽  
Spatio Temporal ◽  
Increasing Trends

Drought is a natural extreme climate event which occurs in most parts of the world. Northeastern China is one of the major agricultural production areas in China and also a typical vulnerable climate zone. To understand the spatio-temporal characteristics of drought over northeastern China, we first assessed the trends of precipitation and temperature. Drought events were then characterized by Standardized Precipitation Evapotranspiration Index over various temporal scales. The Trend Free Prewhitening Mann–Kendall test and distinct empirical orthogonal function, were used to investigate the trends and spatio-temporal patterns of droughts. The results indicate precipitation increasing trends are mostly detected in Heilongjiang and Jinling provinces, however, the majority of the trends are insignificant. Temperature increasing trends are detected over the entire northeastern China and most of them are significant. Decreasing drought trends are observed in Heilongjiang province and some bordering area in Jilin province, whereas increasing trends are noticed in Liaoning province and some bordering area in Jilin province. Two main sub-regions of drought variability—the Liaohe River Plain and the Second Songhua River basin (LS region), and the Songnen Plain and the Lesser Hinggan Mountains (SL region) are identified, and the detected droughts for the two sub-regions correspond well with recorded drought loss. The results will be beneficial for regional water resource management and planning, agriculture production, and ecosystem protection in northeastern China.

scholarly journals Long–term spatio–temporal warming tendency in the Vietnamese Mekong Delta based on observed and high–resolution gridded datasets

2019 ◽  
pp. 01-16
Author(s):  
Dang Nguyen Dong Phuong ◽  
Dang Kien Cuong ◽  
Duong Ton Dam ◽  
Nguyen Kim Loi
Keyword(s):  
High Resolution ◽  
Statistical Tests ◽  
Mekong Delta ◽  
Kendall Test ◽  
Trend Detection ◽  
Homogeneity Test ◽  
Spatio Temporal ◽  
Temperature Records ◽  
Slope Estimator ◽  
Increasing Trends

The Vietnamese Mekong Delta is among the most vulnerable deltas to climate–related hazards across the globe. In this study, the annual mean and extreme temperatures from 11 meteorological stations over the Vietnamese Mekong Delta were subjected to normality, homogeneity and trend analysis by employing a number of powerful statistical tests (i.e. Shapiro–Wilk, Buishand Range test, classical/modified Mann–Kendall test and Sen’s slope estimator). As for spatio–temporal assessment, the well–known (0.5° × 0.5°) high–resolution gridded dataset (i.e. CRU TS4.02) was also utilized to examine trend possibilities for three different time periods (i.e. 1901–2017, 1951–2017 and 1981–2017) by integrating spatial interpolation algorithms (i.e. IDW and Ordinary Kriging) with statistical trend tests. Comparing the calculated test–statistics to their critical values (a = 0.05), it is evident that most of the temperature records can be considered to be normal and non–homogeneous with respect to normality and homogeneity test respectively. As for temporal trend detection, the outcomes show high domination of significantly increasing trends. Additionally, the results of trend estimation indicate that the magnitude of increase in minimum temperature was mostly greater than mean and maximum ones and the recent period (1981–2017) also revealed greater increasing rates compared to the entire analyzed period and second half of the 20th century. In general, these findings yield various evident indications of warming tendency in the Vietnamese Mekong Delta over the last three decades.

scholarly journals 65-year changes of annual streamflow volumes across Europe with a focus on the Mediterranean basin

2020 ◽  
Author(s):  
Daniele Masseroni ◽  
Stefania Camici ◽  
Alessio Cislaghi ◽  
Giorgio Vacchiano ◽  
Christian Massari ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resource Management ◽  
River Flow ◽  
Mediterranean Area ◽  
Positive Trend ◽  
Annual Streamflow ◽  
Continental Scale ◽  
The Mediterranean ◽  
Spatio Temporal ◽  
Climate Change Drivers

Abstract. Determining the spatio-temporal variability of annual streamflow volume plays a relevant role in hydrology for improving and implementing sustainable and resilient policies and practices of water resource management. This study investigates annual streamflow volume trends in a newly-assembled, consolidated and validated dataset of daily mean river flow records from more than 3,000 stations, which cover near-natural basins in more than 40 countries across Europe. Although the dataset contains streamflow time-series from 1850 to 2015 in some stations, the statistical analyses were carried out by including observations from 1950 to 2015 in order to have a consistent and reliable dataset over the continent. Trends were detected calculating the slope of Theil-Sen's line over the annual anomalies of streamflow volume. The results show annual streamflow volume trends emerged at European scale, with a marked negative tendency in Mediterranean regions (about −1 × 103 m3/(km2 year)) and a generally positive trend in northern ones (about 0.5 × 103 m3/(km2 year)). The annual streamflow volume trend patterns appear in agreement with the continental-scale climate change observations in response to climate change drivers. In the Mediterranean area, the declining of annual streamflow volumes started in 1965 and since early 80' volumes are consistently lower than the average. The spatio-temporal annual streamflow volume patterns observed in this work can help to contextualize short-term trends and regional studies already available in the scientific literature as well as to provide a valid benchmark for further accurate quantitative analysis on annual streamflow volumes.

scholarly journals Spatio-temporal analysis of Maximum temperature over Iraq

2018 ◽  
Vol 29 (1) ◽  
pp. 1
Author(s):  
Aws Ali Al Khudhairy
Keyword(s):  
Temporal Trends ◽  
Surface Air Temperature ◽  
Kendall Test ◽  
Temporal Analysis ◽  
Maximum Temperature ◽  
Positive Trend ◽  
Seasonal Temperature ◽  
The North ◽  
Four Seasons ◽  
Spatio Temporal

Monthly Maximum surface air temperature at 23 stations in Iraq were analyzed for temporal trends and spatial variation during 1980-2015.Seasonal and annual temperature was analyzed using Mann-Kendall test to detect the significant trend .The results of temporal analysis showed that during winter ,spring , summer and Autumn have a positive trend in all the parts of Iraq. A tendency has also been observed towards warmer years, with significantly warmer summer and spring periods and slightly warmer autumn and winter, The highest increase is (3.9) oC in Basrah during the summer. The results of spatial analysis using the ArcGIS showed that the seasonal temperature can be divided into two or three distinct areas with high temperature in the south and decreasing towards north, where the trend of spatial temperature were decreasing from south to the north in all the four seasons.

scholarly journals Historical drought patterns over Canada and their teleconnections with large-scale climate signals

2018 ◽  
Vol 22 (6) ◽  
pp. 3105-3124 ◽  
Author(s):  
Zilefac Elvis Asong ◽  
Howard Simon Wheater ◽  
Barrie Bonsal ◽  
Saman Razavi ◽  
Sopan Kurkute
Keyword(s):  
Large Scale ◽  
Southern Oscillation ◽  
Low Frequency ◽  
Kendall Test ◽  
Wavelet Coherence ◽  
Climate Indices ◽  
Data Sets ◽  
Canadian Prairies ◽  
Agriculture Industry ◽  
Spatio Temporal

Abstract. Drought is a recurring extreme climate event and among the most costly natural disasters in the world. This is particularly true over Canada, where drought is both a frequent and damaging phenomenon with impacts on regional water resources, agriculture, industry, aquatic ecosystems, and health. However, nationwide drought assessments are currently lacking and impacted by limited ground-based observations. This study provides a comprehensive analysis of historical droughts over the whole of Canada, including the role of large-scale teleconnections. Drought events are characterized by the Standardized Precipitation Evapotranspiration Index (SPEI) over various temporal scales (1, 3, 6, and 12 consecutive months, 6 months from April to September, and 12 months from October to September) applied to different gridded monthly data sets for the period 1950–2013. The Mann–Kendall test, rotated empirical orthogonal function, continuous wavelet transform, and wavelet coherence analyses are used, respectively, to investigate the trend, spatio-temporal patterns, periodicity, and teleconnectivity of drought events. Results indicate that southern (northern) parts of the country experienced significant trends towards drier (wetter) conditions although substantial variability exists. Two spatially well-defined regions with different temporal evolution of droughts were identified – the Canadian Prairies and northern central Canada. The analyses also revealed the presence of a dominant periodicity of between 8 and 32 months in the Prairie region and between 8 and 40 months in the northern central region. These cycles of low-frequency variability are found to be associated principally with the Pacific–North American (PNA) and Multivariate El Niño/Southern Oscillation Index (MEI) relative to other considered large-scale climate indices. This study is the first of its kind to identify dominant periodicities in drought variability over the whole of Canada in terms of when the drought events occur, their duration, and how often they occur.

Evaluation of spatio-temporal trends of groundwater quality in different land uses using Kendall test

2012 ◽  
Vol 16 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Dugin Kaown ◽  
Yunjung Hyun ◽  
Gwang-Ok Bae ◽  
Chang Whan Oh ◽  
Kang-Kun Lee
Keyword(s):  
Groundwater Quality ◽  
Temporal Trends ◽  
Kendall Test ◽  
Land Uses ◽  
Spatio Temporal

scholarly journals Extent and Variation of Nitrogen Losses from Non-legume Field Crops of Conterminous United States

Nitrogen ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 34-51
Author(s):  
Amitava Chatterjee
Keyword(s):  
United States ◽  
Management Strategies ◽  
Application Rate ◽  
Fertilizer N ◽  
N Loss ◽  
N Losses ◽  
Field Crops ◽  
N Application Rate ◽  
Spatio Temporal ◽  
N Management

Nitrogen (N) losses from field crops have raised environmental concerns. This manuscript accompanies a database of N loss studies from non-legume field crops conducted across the conterminous United States. Cumulative N losses through nitrous oxide-denitrification (CN2O), ammonia volatilization (CNH3), and nitrate leaching (CNO3−) during the growing season and associated crop, soil, and water management information were gathered to determine the extent and controls of these losses. This database consisted of 404, 26, and 358 observations of CN2O, CNH3, and CNO3− losses, respectively, from sixty-two peer-reviewed manuscripts. Corn (Zea mays) dominated the N loss studies. Losses ranged between −0.04 to 16.9, 2.50 to 50.9, and 0 to 257 kg N ha−1 for CN2O, CNH3 and CNO3−, respectively. Most CN2O and CNO3− observations were reported from Colorado (n = 100) and Iowa (n = 176), respectively. The highest values of CN2O, and CNO3− were reported from Illinois and Minnesota states, and corn and potato (Solanum tuberosum), respectively. The application of anhydrous NH3 had the highest value of CN2O loss, and ammonium nitrate had the highest CNO3− loss. Among the different placement methods, the injection of fertilizer-N had the highest CN2O loss, whereas the banding of fertilizer-N had the highest CNO3− loss. The maximum CNO3− loss was higher for chisel than no-tillage practice. Both CN2O and CNO3− were positively correlated with fertilizer N application rate and the amount of water input (irrigation and rainfall). Fertilizer-N management strategies to control N loss should consider the spatio-temporal variability of interactions among climate, crop-and soil types.

scholarly journals Largest enterprises in the Czech Republic: A spatio-temporal perspective

2012 ◽  
Vol 60 (7) ◽  
pp. 329-336 ◽  
Author(s):  
Jana Sucháček ◽  
Petra Baránek
Keyword(s):  
Czech Republic ◽  
Geographical Location ◽  
Capital City ◽  
Location Factors ◽  
Spatial Profile ◽  
Temporal Perspective ◽  
Large Enterprise ◽  
The Czech Republic ◽  
Spatio Temporal ◽  
Large Enterprises

This article focuses on spatial structure of one hundred largest enterprises in the Czech Republic from evolutionary perspective. The location of large enterprise headquarters in the Czech Republic and its implications for country’s economic spatial profile and unevenly distributed economic power is discussed thoroughly. The whole analysis is pragmatically accomplished at the level of self-governmental NUTS III regions. As it is shown, intense concentration processes in the location of largest enterprise headquarters were observed during the analyzed period between 1995 and 2010. The capital city with its surroundings proved to be the winners of this process. Currently, the spatial pattern of afore mentioned head offices is basically stabilized. On the other hand, weight of large enterprises of many regions is almost negligible and subsequently, rank of individual regions can be rather volatile. Generally speaking, economic map of the Czech Republic is not entirely in compliance with country’s settlement system. Simultaneously, fundamental factors determining the location of large enterprise head offices are evaluated also from qualitative perspective. Traditional hard location factors, such as infrastructure, geographical location or agglomeration economies turned out to be decisive for location decision-making. Apart from Prague, headquarters of large enterprises tend to prefer other big towns in the country, such as Brno, Ostrava, Olomouc, Hradec Králové or Plzeň.

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