Spatial and temporal characterization of climate at regional scale using homogeneous monthly precipitation and air temperature data: an application in Calabria (southern Italy)

2014 ◽  
Vol 46 (4) ◽  
pp. 629-646 ◽  
Author(s):  
T. Caloiero ◽  
G. Buttafuoco ◽  
R. Coscarelli ◽  
E. Ferrari
Keyword(s):  
Regional Scale ◽  
Kendall Test ◽  
Temperature Data ◽  
Winter Period ◽  
Positive Trend ◽  
Monthly Precipitation ◽  
Average Temperature ◽  
Increasing Trend ◽  
Precipitation And Temperature

In the present study, an approach for a climate characterization based on a statistical analysis of monthly precipitation and temperature data is presented. First, the original database (1916–2010) was homogenized and a geostatistical analysis was carried out to characterize the monthly mean distribution of the two variables in the study area. Then, temporal change of precipitation and temperature were evaluated through the Mann–Kendall test. Finally, to better assess the climate patterns in Calabria, a climatic characterization was carried out by means of the Péguy climograph. Results have shown a decreasing trend for autumn–winter rainfall and an increasing trend in summer. With respect to the average temperature, the analyses revealed a positive trend in late spring and summer, mainly due to the increase in the minimum values, and a negative trend in the autumn–winter period, mainly due to a decrease in the maximum values. The analysis of the Péguy climographs allowed the dataset to be divided into three groups, depending on the different elevation of the gauges. Moreover, different temporal behaviours were detected by analysing the climographs in three sub-periods.

scholarly journals Innovative Trend Analysis of Precipitation in the Lake Issyk-Kul Basin, Kyrgyzstan

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 332 ◽  
Author(s):  
Yilinuer Alifujiang ◽  
Jilili Abuduwaili ◽  
Balati Maihemuti ◽  
Bilal Emin ◽  
Michael Groll
Keyword(s):  
Trend Analysis ◽  
Resource Planning ◽  
Kendall Test ◽  
Trend Test ◽  
Lake Basin ◽  
Positive Trend ◽  
Monthly Precipitation ◽  
Innovative Trend Analysis ◽  
Mann Kendall Test ◽  
Increasing Trends

The analysis of various characteristics and trends of precipitation is an essential task to improve the utilization of water resources. Lake Issyk-Kul basin is an upper alpine catchment, which is more susceptible to the effects of climate variability, and identifying rainfall variations has vital importance for water resource planning and management in the lake basin. The well-known approaches linear regression, Şen’s slope, Spearman’s rho, and Mann-Kendall trend tests are applied frequently to try to identify trend variations, especially in rainfall, in most literature around the world. Recently, a newly developed method of Şen-innovative trend analysis (ITA) provides some advantages of visual-graphical illustrations and the identification of trends, which is one of the main focuses in this article. This study obtained the monthly precipitation data (between 1951 and 2012) from three meteorological stations (Balykchy, Cholpon-Ata, and Kyzyl-Suu) surrounding the Lake Issyk-Kul, and investigated the trends of precipitation variability by applying the ITA method. For comparison purposes, the traditional Mann–Kendall trend test also used the same time series. The main results of this study include the following. (1) According to the Mann-Kendall trend test, the precipitation of all months at the Balykchy station showed a positive trend (except in January (Zc = −0.784) and July (Zc = 0.079)). At the Cholpon-Ata and Kyzyl-Suu stations, monthly precipitation (with the same month of multiple years averaged) indicated a decreasing trend in January, June, August, and November. At the monthly scale, significant increasing trends (Zc > Z0.10 = 1.645) were detected in February and October for three stations. (2) The ITA method indicated that the rising trends were seen in 16 out of 36 months at the three stations, while six months showed decreasing patterns for “high” monthly precipitation. According to the “low” monthly precipitations, 14 months had an increasing trend, and four months showed a decreasing trend. Through the application of the ITA method (January, March, and August at Balykchy; December at Cholpon-Ata; and July and December at Kyzyl-Suu), there were some significant increasing trends, but the Mann-Kendall test found no significant trends. The significant trend occupies 19.4% in the Mann-Kendall test and 36.1% in the ITA method, which indicates that the ITA method displays more positive significant trends than Mann–Kendall Zc. (3) Compared with the classical Mann-Kendall trend results, the ITA method has some advantages. This approach allows more detailed interpretations about trend detection, which has benefits for identifying hidden variation trends of precipitation and the graphical illustration of the trend variability of extreme events, such as “high” and “low” values of monthly precipitation. In contrast, these cannot be discovered by applying traditional methods.

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.

scholarly journals Simulation of River Discharges in Major Watersheds of Northwestern Java From 1901 To 2006

2018 ◽  
Author(s):  
Miga Magenika Julian ◽  
Fumihiko Nishio ◽  
Poerbandono ◽  
Philip J. Ward
Keyword(s):  
21St Century ◽  
Input Data ◽  
Kendall Test ◽  
Positive Trend ◽  
Management Option ◽  
Time Step ◽  
Early 21St Century ◽  
Discharge Simulation ◽  
Increasing Trends ◽  
Precipitation And Temperature

This study is intended to simulate the river discharges in major watersheds of northwestern Java, Indonesia. The five largest watersheds are considered: Ciujung, Cisadane, Ciliwung, Citarum, and Cimanuk. The simulation period covers the 20th century and early 21st century, from January 1901 to June 2006, at a monthly time step. Discharge simulation was carried out using STREAM (Spatial Tools for River Basins and Environmental and Analysis of Management Option). The input data for the simulation are climate (precipitation and temperature), land cover and topographic data. Setup and analysis of input data are also part of this study. The Mann-Kendall test and linear regression were used to detect trends. Temperature datasets show statistically significant increasing trends for all periods and areas. Significant increasing trends of precipitation occurred in the latest 16-year period (1990-2006) in hilly and middle areas. A positive trend of simulated discharge is seen in all watersheds and periods. They are only significant for Ciujung (periods of 1950-2006 and 1975-2006), Cisadane (periods of 1950-2006 and 1990-2006), and Ciliwung (periods of 1950-2006, 1975-2006, and 1990- 2006). The most noteworthy trend is seen in the 1990-2006 period. Over the course of the 20th and early decade of the 21st century, monthly discharges have increased by 3% to 9%.

scholarly journals Evaluating the Spatiotemporal Characteristics of Meteorological Drought in Bangladesh Using Effective Drought Index

2019 ◽  
Author(s):  
Mohammad Kamruzzaman ◽  
Syewoon Hwang ◽  
Jaepil Cho ◽  
Min-Won Jang ◽  
Hanseok Jeong
Keyword(s):  
Central Region ◽  
Drought Index ◽  
Regional Scale ◽  
Mitigation Strategies ◽  
Monthly Precipitation ◽  
Effective Drought Index ◽  
Spatiotemporal Characteristics ◽  
Increasing Trend ◽  
North Western

This study aims to assess the spatiotemporal characteristics of meteorological droughts in Bangladesh during 1981–2015 using the Effective Drought Index (EDI). Monthly precipitation data for 36 years (1980-2015) obtained from 27 metrological stations, were used in this study. The EDI performance was evaluated for four sub-regions over the country through comparisons with historical drought records identified at the regional scale. Analysis at a regional level showed that EDI could reasonably detect the drought years/events during the study period. The study also revealed that the overall drought severity had increased during the past 35 y; the most significant increasing trend was observed in the central region. The characteristics (severity and duration) of drought were also analysed in terms of spatiotemporal evolution of the frequency of drought events. It was found that the western and central regions of the country are comparatively more vulnerable to drought. Moreover, the southwestern region is more prone to extreme drought, whereas the central region is more prone to severe droughts. In addition, the central region was more prone to extra-long-term droughts, while the coastal areas in the southwestern as well as in the central and north-western region were more prone to long-term droughts. The frequency of droughts in all categories significantly increased during the last quinquennial period (2011 to 2015). The seasonal analysis showed that the north-western areas were prone to extreme droughts during the Kharif (wet) and Rabi (dry) seasons. The central and northern regions were affected by recurring severe droughts in all cropping seasons. Further, the most significant increasing trend of the drought-affected area was observed within the central region, especially during the pre-monsoon (March-May) season. The results of this study can aid policymakers in the development of drought mitigation strategies in the future.

Spatiotemporal Evolution of the Drought and Flood in Northeast China

2014 ◽  
Vol 1010-1012 ◽  
pp. 1075-1083 ◽  
Author(s):  
Ru Huang ◽  
Deng Hua Yan
Keyword(s):  
Northeast China ◽  
Linear Regression Analysis ◽  
Kendall Test ◽  
Monthly Precipitation ◽  
Upward Trend ◽  
Spatiotemporal Evolution ◽  
Drought And Flood ◽  
Increasing Trend ◽  
Change Trend ◽  
Monthly Precipitation Data

In order to reduce the losses of drought and flood disasters, the spatiotemporal characteristics and evolution of drought and flood in Northeast China were analyzed by Z index based on the monthly precipitation data of 111 meteorological stations during 1961-2013.The Mann–Kendall test and linear regression analysis were used to analyze the change trend of drought and flood. The main conclusions are as follows: (1) Affected by the monsoon climate, flood is concentrated in summer extensively and frequently in Northeast China, while drought is concentrated in winter. (2) Drought mainly occurs in January, February, March, November and December concentrated in east and southeast of Northeast China. Flood is found in May to September. Especially The highest frequency of flood is observed in July (up to 84.9%), next is August with 69.8%, and followed by June with 48.7%. (3)7 months in a year (March-June and October-December ) show wetting trend over Northeast China , while 3 months (July-September) are observed drying trends. Significant upward trend of wet conditions occur in March and December; while significant trends towards drier conditions occur in September. (4) Drought areas dominate the Northeast China in January, February, March, November and December with a decreasing trend. Flood areas dominate the Northeast China from May to September. Extensive flood is most likely occurred in July. Flood area in May and June show an increasing trend, while a decreasing trend is from July to September.

scholarly journals Long term rainfall trend over meteorological sub divisions and districts of India

MAUSAM ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 439-450
Author(s):  
SURINDER KAUR ◽  
SUMANT KUMAR DIWAKAR ◽  
ASHOK KUMAR DAS
Keyword(s):  
Uttar Pradesh ◽  
Kendall Test ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Positive Trend ◽  
Rainfall Analysis ◽  
Increasing Trend ◽  
Long Term Trend ◽  
Agriculture Water

In this paper the long term trend of annual and seasonal rainfall over different districts, Meteorological (Met.) sub-divisions and whole India have been studied using the long term rainfall data for the period from 1901 to 2013. The changes in amount and pattern of rainfall have a significant impact on agriculture, water resources management and overall economy of the country. Mann-Kendall test is applied to check the significance of the trend. Linear Regression and Theil-Sen’s non parametric test has been applied to estimate the trend. The study is carried out for 632 districts and 34 sub divisions of India by utilizing the gridded rainfall data (0.25° × 0.25°) over the main land except Andaman & Nicobar and Lakshadweep islands. Many authors have studied that extreme events are increasing but there is no trend in Pan India’s rainfall. It is observed from the annual rainfall analysis 10% of the number of districts are showing significant increasing trend and 13% significant decreasing (mainly in Uttar Pradesh) trend whereas irrespective of high and low rainfall regions, 10% area of the country is showing significant increasing trend and 8% of the area of the country showing significant decreasing trend in annual rainfall. In Meteorological Sub divisions, east & west UP are showing significant negative trend and some of the coastal sub divisions are showing positive trend. It is also observed that the country’s rainfall is not showing any trend.

scholarly journals Trends in rainfall amount and number of rainy days in river basins of India (1951–2004)

2011 ◽  
Vol 42 (4) ◽  
pp. 290-306 ◽  
Author(s):  
Vijay Kumar ◽  
Sharad K. Jain
Keyword(s):  
Monsoon Rainfall ◽  
Statistical Significance ◽  
Kendall Test ◽  
River Basins ◽  
Rainfall Amount ◽  
Annual Rainfall ◽  
Positive Trend ◽  
Significant Positive Trend ◽  
Increasing Trend ◽  
Rainy Days

This study aims to determine trends in annual and seasonal rainfall and rainy days over different river basins across India. The data used consists of daily gridded rainfall at 1° × 1° resolution for the period 1951–2004. Sen's non-parametric estimator of slope was used to estimate the magnitude of trend whose statistical significance was assessed by the Mann–Kendall test. Among 22 basins studied, 15 showed a decreasing trend in annual rainfall; only one basin showed a significant decreasing trend at 95% confidence level. Of the 6 basins showing an increasing trend, 1 basin showed a significant positive trend. The monsoon rainfall increased over 6 basins, decreased over 16 basins and a decreasing trend for 2 basins was found statistical significant. With the exception of Ganga, Brahmaputra and EFR4, all river basins experienced the same direction of trend in monsoon and annual rainfall. Four river basins experienced increasing (non-significant) trend in annual rainy days; three basins did not show any change in annual rainy days whereas 15 basins have shown a decreasing trend in annual rainy days. The decreasing trend in three basins was statistically significant. Most of the basins have shown the same direction of trend in rainfall and rainy days at the annual and seasonal scale.

scholarly journals The Spatial-temporal Variation of Precipitation and Temperature in Xinjiang in Recent 50 Years

2019 ◽  
Vol 1 ◽  
pp. 1-3
Author(s):  
Yuzhu Wang ◽  
Haowen Yan ◽  
Xiaoping Wang ◽  
Zhuo Wang
Keyword(s):  
Spatial Distribution ◽  
Temporal Variation ◽  
Annual Average ◽  
Northern Xinjiang ◽  
Average Temperature ◽  
Local Areas ◽  
Increasing Trend ◽  
Annual Average Temperature ◽  
Precipitation And Temperature ◽  
Southern Xinjiang

<p><strong>Abstract.</strong> Research purpose: To master the spatial-temporal evolution of precipitation and temperature in Xinjiang, and to provide reference for industrial, agricultural and transportation industries in the study area. Date and Rrsearch methods: Based on monthly precipitation and temperature data of 64 weather stations in Xinjiang in recent 50 years，the spatial-temporal variation of precipitation and temperature were analyzed by the methods of simple linear regression, 5-year moving average, radial basis function interpolation, sliding -t test, accumulated variance analysis, Mann-Kendall and morlet wavelet transform.</p><p>Research conclusion:</p><p>(1) The annual average precipitation (8.65&amp;thinsp;mm/10&amp;thinsp;a) in Xinjiang showed a significant increasing trend, and the increasing trend in local areas was:Northern Xinjiang (14.83&amp;thinsp;mm/10&amp;thinsp;a) &amp;gt; Southern Xinjiang(7.76&amp;thinsp;mm/10&amp;thinsp;a) &amp;gt; Eastern Xinjiang (3.37&amp;thinsp;mm/10&amp;thinsp;a).</p><p>(2) The spatial distribution of tendency rate of annual precipitation is basically the same as the spring, summer and autumn in Xinjiang, the tendency rate decreases from northwest to southeast, but the tendency rate of winter precipitation decreases from north to south.</p><p>(3) The precipitation of Xinjiang changed abruptly in 1989, Southern Xinjiang was relatively earlier (1986), Northern Xinjiang (1991) and Eastern Xinjiang (1990) were relatively delay.</p><p>(4) The main cycle of precipitation was 26&amp;ndash;30&amp;thinsp;a in Xinjiang and local areas, which predicts that the next 10 years will be a wet season.</p><p>(5) The annual average temperature (0.44&amp;thinsp;°C / 10&amp;thinsp;a) in Xinjiang is very significant, and the temperature increase trend in local areas is: Eastern Xinjiang (0.58&amp;thinsp;°C / 10&amp;thinsp;a) &amp;gt; Northern Xinjiang (0.45&amp;thinsp;°C / 10&amp;thinsp;a) &amp;gt; Southern Xinjiang (0.31&amp;thinsp;°C / 10&amp;thinsp;a).</p><p>(6) The spatial distribution of tendency rate of annual average temperature is basically the same as the four seasons in Xinjiang, and the tendency rate showed a decreasing trend from northeast to southwest.</p><p>(7) The temperature change of Xinjiang occurred in 1988,Northern Xinjiang was 1988 （relatively earlier), Southern Xinjiang and Eastern Xinjiang were 1992 (relatively delay).</p><p>(8) The main cycle of temperature in Xinjiang and local areas was 25&amp;ndash;30&amp;thinsp;a. It was predicted that the next 10 years would be high temperature period.</p>

scholarly journals Trend analysis of seasonal rainfall and temperature pattern in Damota Gale districts of Wolaita Zone, Ethiopia

2021 ◽  
Author(s):  
Elias Bojago ◽  
Dalga YaYa
Keyword(s):  
Trend Analysis ◽  
Meteorological Data ◽  
Statistical Significance ◽  
Kendall Test ◽  
Maximum Temperature ◽  
Temperature Pattern ◽  
Positive Trend ◽  
Annual Minimum Temperature ◽  
Increasing Trend ◽  
Mann Kendall Test

Abstract This paper investigated the recent trends of precipitation and temperature on Damota Gale districts of Wolaita Zone. This study used the observed historical meteorological data from 1987 to 2019 to analyze the trends. The magnitude of the variability or fluctuations of the factors varies according to locations. Hence, examining the spatiotemporal dynamics of meteorological variables in the context of changing climate, particularly in countries where rain-fed agriculture is predominant, is vital to assess climate-induced changes and suggest feasible adaptation strategies. Both rainfall and temperature data for a period of 1987 to 2019 were analyzed in this study. Statistical trend analysis techniques namely Mann–Kendall test and Sen's slope estimator were used to examine and analyze the problems. The long-term trend of rainfall and temperature was evaluated by linear regression and Mann–Kendall test. The temperature was shown a positive trend for both annual and seasonal periods and had a statistical significance of 95%. This study concluded that there was a declining rainfall in the three seasons; spring, summer and winter but in autumn it shows increasing trends and rapid warming, especially in the last 32 years. The detailed analysis of the data for 32 years indicate that the annual maximum temperature and annual minimum temperature have shown an increasing trend, whereas the Damota Gale seasonal maximum and minimum temperatures have shown an increasing trend. The findings of this study will serve as a reference for climate researchers, policy and decision-makers.

Short-Term Precipitation and Temperature Trends along an Elevation Gradient in Northeastern Puerto Rico

2015 ◽  
Vol 19 (3) ◽  
pp. 1-33 ◽  
Author(s):  
Ashley E. Van Beusekom ◽  
Grizelle González ◽  
Maria M. Rivera
Keyword(s):  
Climate Change ◽  
Puerto Rico ◽  
Elevation Gradient ◽  
Daily Maximum ◽  
Positive Trend ◽  
Tropical Regions ◽  
Daily Minimum ◽  
Increasing Trend ◽  
Order Of Magnitude ◽  
Precipitation And Temperature

Abstract As is true of many tropical regions, northeastern Puerto Rico is an ecologically sensitive area with biological life that is highly elevation dependent on precipitation and temperature. Climate change has the potential to increase the risk of losing endemic species and habitats. Consequently, it is important to explore the pattern of trends in precipitation and temperature along an elevation gradient. Statistical derivatives of a frequently sampled dataset of precipitation and temperature at 20 sites along an elevation gradient of 1000 m in northeastern Puerto Rico were examined for trends from 2001 to 2013 with nonparametric methods accounting for annual periodic variations such as yearly weather cycles. Overall daily precipitation had an increasing trend of around 0.1 mm day−1 yr−1. The driest months of the annual dry, early, and late rainfall seasons showed a small increasing trend in the precipitation (around 0.1 mm day−1 yr−1). There was strong evidence that precipitation in the driest months of each rainfall season increased faster at higher elevations (0.02 mm day−1 more increase for 100-m elevation gain) and some evidence for the same pattern in precipitation in all months of the year but at half the rate. Temperature had a positive trend in the daily minimum (around 0.02°C yr−1) and a negative trend in the daily maximum whose size is likely an order of magnitude larger than the size of the daily minimum trend. Physical mechanisms behind the trends may be related to climate change; longer-term studies will need to be undertaken in order to assess the future climatic trajectory of tropical forests.

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