Trend Analysis Of Precipitation Research Articles

Trend Analysis of Precipitation, Runoff and Major Ions for the Russian Part of the Selenga River Basin

At present, the problem of climate change is becoming increasingly acute. This is especially pressing for Lake Baikal, a World Natural Heritage site. The Russian part of the Selenga watershed is a suitable site for climate change research. The study of changes in precipitation, runoff, and chemical runoff is important for sustainable water resources management. This study presents a trend analysis of precipitation and runoff at hydrological stations and weather stations in the Russian part of the Selenga River basin. A comparative analysis of the concentrations of major ions in the surface water of the Selenga River depending on water levels was also carried out. Analysis of the data series on precipitation revealed a slight negative trend at the Novoselenginsk, Ulan-Ude, and Kabansk stations, and a weak positive trend—at the Kyakhta station. Runoff analysis revealed negative trends at the two used stations (Novoselenginsk and Mostovoi). The hydrochemical regime of the Selenga River is characterized by an increase in major ions and salinity during winter low-water periods, and a decrease during high-water periods. Mineralization and major ion content are lower in the high-water period (2019–2021) than in the low-water period (2015–2017).

Decadal Impacts of Climate Change on Rainfed Agriculture Community in Western Somaliland, Africa

The western region of Somaliland is prone to climate change and variability due to the widespread use of rainfed agriculture, which has been the practice historically since the colonization era; however, this mode of livelihood is losing its significance due to climate change. This research aims to examine the impact of climate elements’ trends (rainfall and temperature) on rainfed agriculture communities and how these changes affect the rainfed agriculture community. The specific objectives of this study are to determine the major trends of precipitation and temperature over the past three decades, and to assess the level of awareness of climate change in communities’ perception of environmental change in terms of rainfed agriculture. Hence, the study adopted a mixed-methodology approach to concluding the quantitative and qualitative aspects of the research. The main outcome of this study was that climate change has been an active challenge in western rainfed agriculture regions of Somaliland for the last three decades. Decadal precipitation and temperature trend analysis (1985–2015) indicated reduced rainfall both annual and seasonal, and an increase in annual temperature, both in terms of the maximum and minimum. The decrease in annual total rainfall from the Awdal and Waqooyi Galbeed regions was 2 mm/year and 1.5 mm/year, respectively, while in the long rainy season, the decrease of rainfall was 1.4 mm per season and 0.88 mm per season, respectively. In the case of maximum and minimum annual temperatures, both stations depict an increase in temperature. This increase in temperature was 0.043–0.045 °C for the Awdal region and 0.06–0.02 °C for the Waqooyi Galbeed. The qualitative phase of this study supported the quantitative observations, and respondents (≥45 years of age) reported decreasing annual rainfall, a declining long rainy season, and increasing maximum and minimum temperatures. Furthermore, participants mentioned an increase in the occurrence of drought, a reduction of rainfed agriculture productivity, the disappearance of indigenous plants and animals, and an increase of exotic plant species. In addition to that, respondents outlined current adaptation practices; however, these adaptation strategies are short-term, and farmers need more appropriate and practical adaptation practices in the future.

Trend analysis of precipitation for protected areas and pasturelands in southwest Amazônia between 1998 and 2019

This article presents a spatio-temporal analysis of the rainfall distribution for the State of Rondônia. Data from the Tropical Rainfall Measurement Mission were analyzed, comprising a time series from 1998 to 2019. Data obtained from remote sensing were validated with data collected from rainfall stations. Trend analyzes were developed by applying the Mann-Kendall test. The spatialization of the increase and decrease of precipitation for the state was performed using the slope method of Sen. The rainfall stations showed a percentage of underestimation of −66%, an average standard error of 156.8 mm.year−1 an average correlation (r) of 0.66, indicating an average degree of agreement (d) equivalent to 0.68. The decrease in annual precipitation occurs mainly in the north of the state. For the dry season, protected areas again showed a smaller reduction than unprotected areas. Protected areas showed a reduction of 6 mm.year−1 while unprotected areas showed a reduction of 8 mm.year−1, also in the north of the state. According to the TRMM data obtained from remote sensing, a reduction of approximately 1.5 mm.year−1 can be seen, mainly in the northern region of the state of Rondônia, which has extensive areas of conversion of native forest to pasture and an increase in approximately 1 mm.year−1 in the southwest region of the state, which has the largest extension of protected natural areas.

Precipitation trend analysis in Macta basin (northwest of Algeria)

Precipitation trend analysis in Macta basin (northwest of Algeria)

Assessment of reservoir performance under climate change: A case study in Shumbrite reservoir, South Gojjam sub-basin, Ethiopia

Climate change has the potential to reduce the water resource availability and hence the amount of storage in reservoirs. In this study, we assessed the impact of climate change on the performance of the Shumbrite reservoir using outputs from the CORDEX-Africa project, MPI Global Circulation Model (GCM) under three Representative Concentration Pathways (i.e., RCP2.6, RCP4.5 and RCP8.5). The trend analysis of future precipitation shows a decrease in the range of 0.57%–4.2%, with a maximum decrease under RCP2.6, and temperature (both maximum and minimum) shows an increasing trend as compared to the baseline period. The HBV model simulated future mean annual flow volume shows a decrease (ranges 0.06% to 1.64%) for RCP2.6 and RCP4.5 and a significant increase of 5.03% for RCP8.5 compared to the baseline period. Mean annual irrigation water demand from CROPWAT shows an increase (0.74% to 8.4%) for all RCPs compared to the baseline period. The time-based reliability for the Shumbrite reservoir has an average value above 80%. The resilience values are below 50% for all RCPs and hence the reservoir will take an extended period to recover from an inability to achieve the target demand volume. The dimensionless vulnerability shows a value below 50% which indicates that the reservoir has no insufficient flow to meet the demand. Generally, the reservoir can be used sustainably with operation rule curves. Generally, this study adds a contribution to the evaluation of small-scale reservoirs under a changing climate and the preparation of guide curves for the respective release.

Variations of precipitation and runoff in the Bagmati river basin, Bihar, India

AbstractThe trend analysis of precipitation for four rain gauge stations and runoff for Hayaghat station in the Bagmati river basin is carried out in this work by adopting modified Mann–Kendall and Sen's slope methods. Primary and secondary data are used for finding the monthly, seasonal, and annual trends at four stations. Primary data are the observed rainfall from 1981 to 2013 which were collected from IMD Pune, observed runoff data were collected from CWC Patna and secondary data from the National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis rainfall data for the period 1981–2013. The goals of this research are (i) to determine rainfall and runoff trend analysis, as well as the relationship between observed rainfall data and NCEP/NCAR reanalysis secondary data for four stations and (ii) to find the correlation between observed rainfall data and runoff data for all four seasons. The correlation analysis of observed rainfall and NCEP/NCAR reanalysis data shows a very good correlation ranging between 0.6111 and 0.7435. Rainfall is increasing during and after the monsoon at all selected stations, except during the monsoon season in Dhenge. Correlation analysis of rainfall and runoff shows ranges from 0.3724 to 0.4721 for all the four seasons. The correlation of rainfall and runoff is relatively good in monsoon season.HIGHLIGHTSTo determine rainfall and runoff trends, as well as the relationship between observed rainfall data and NCEP/NCAR reanalysis secondary data for four stations. To find the correlation between observed rainfall and runoff data for all four seasons.

Wavelet transform-based trend analysis of streamflow and precipitation in Upper Blue Nile River basin

Study regionUpper Blue Nile River Basin, Ethiopia Study focusThis study aims to determine possible trends in monthly, seasonal and annual precipitation and streamflow series. The Discrete Wavelet Transform (DWT) was used to obtain detailed information about the time-frequency conditions of six meteorological and five streamflow stations during 1984–2014. The Mann-Kendall test was also applied to the original and the DWT components to determine which periodicities are dominant in reproducing the observed trends. The combined DWT and Mann-Kendall test has not been explored in the UBNRB context. We used three criteria to determine a suitable wavelet, decomposition level, and signal extension mode. From these criteria, the bias ratio between the wavelet approximation series and the original time series was proposed and explored in this study. New hydrological insights for the regionResults show that almost all the precipitation stations experience an insignificant but increasing trend, whereas the streamflow stations exhibit an increasing trend at a 5% significance level. The combined use of DWT and the Mann-Kendall test show that periodic events up to 4 years are more influential in affecting the observed trends.

Historical Trends Associated with Annual Temperature and Precipitation in Aegean Turkey, Where Are We Heading?

The trend analysis of annual temperature (daily average) and total precipitation has been conducted for 14 stations located in the Aegean Region, Turkey. The Sen, Spearman’s rho, and Mann-Kendall test methods are used in the detection of the historical trends in the region. The Pettitt test is also implemented to find the significance of the trend, while the Theil-Sen approach is applied to detect the change point(s) in the time series. Findings of the following study indicate that both precipitation and temperature time series in the selected stations depict statistically significant trends with increasing nature. The rate of increase in precipitation and temperature by the Theil-Sen test is found to be 4.2–7.9 mm/year and 0.20–0.35 °C/decade, respectively. It is also found that the turn points of the temperature trends determined by the Pettitt test occurred in 1998 for all the stations. According to the results, the magnitude of the extreme events would change in the future, which may help in conceptualizing the framework and the resilience of the infrastructures against climate change.

Comparative analysis of long-term precipitation trends and its implication in the Modjo catchment, central Ethiopia

Abstract Understanding trends and variability of precipitation is essential to improve water resources utilization as well as agricultural activities. This study aims to investigate the spatiotemporal trends and variability of rainfall in the Modjo watershed, central Ethiopia. The Mann-Kendall trend (M–K) test, innovative trend analysis (ITA) and Sen's slope estimator were used to determine temporal trends, while the inverse distance weighted interpolation technique was adopted to visualize the spatial trends in time series. The result showed that complex patterns of rainfall variability that range from 16 to 59%, 18 to 63%, and 50 to 90% for the annual, summer, and spring seasons, respectively was observed over the study watershed. The result also indicated that significant trend (p < 0.05) in annual rainfall was detected only in 28.6% and 42.9% of the stations under the M-K test and ITA method, respectively, which indicates relatively more significant trends are displayed by the ITA method than the M–K test. At the seasonal scale, positive trends have been more dominant in the summer season (Z > 0, SITA > 0), whereas negative trends (Z < 0, SITA < 0) were detected in the spring season. Comparatively, the ITA method is found to be robust and allows more detailed trend analysis results using graphical illustrations for extreme events. The study concludes that the increasing and decreasing trends in summer and spring rainfall patterns could have implications leading to an increase in extreme events and lower agricultural productivity, respectively. The result suggests the need for planning effective adaptation strategies at the regional and local scales.

Investigation of the trend and cycles using the long-term records of annual precipitation in Shandong, China

Abstract The length of historical records is important for analyzing trends and multidecadal variabilities in precipitation. Conventional studies usually used historical precipitation data less than 60 years, which may cause inaccurate precipitation predictions. To better understand the effects of the study period on precipitation trends and cycles, the Mann–Kendall test and Sen's slope test were applied to analyze the trend and wavelet, while the multi-temporal analysis was used to study the cycles of long historical precipitation data at four rain gauge stations in Shandong Province, China. The analysis results using long-term records show an insignificant upward trend and a longer cycle in the annual precipitation, whereas a downward trend is found when using short-term records. Furthermore, it is found that selecting the length of the representative cycle derived from the precipitation data series as the time scale for the study proved to be more reasonable. A thorough consideration of the impact of cycles on trends should, therefore, be taken to facilitate a more accurate precipitation trend analysis.

Innovative polygon trend analysis of monthly precipitation (1952–2015) in the Hindukush‐Karakoram‐Himalaya river basins of Pakistan

AbstractThe Hindukush‐Karakoram‐Himalayas (HKH) mountainous range supplies water to 10 river basins serving eight countries. The present study focuses on the river basins located within the HKH region in Pakistan. The modified Soil and Water Assessment Tool (SWAT+) was used to split the research region into 13 sub‐basins. The Mann–Kendall, Sen's slope, innovative polygon trend analysis (IPTA), and innovative trend analysis (ITA) methods were used for the monthly precipitation time series. The Shyok sub‐basin (central Karakoram) experienced rising trends for all seasons, while the southwestern Karakoram (Hunza) showed a rising trend only for the winter. The Hindukush Mountain Range feeds five sub‐basins (Gilgit, Chitral, Swat, Kabul, and Kurram). The Gilgit and Kurram sub‐basins observed an upward trend for all seasons. A falling trend in spring and transition from spring (falling) to summer (rising) was observed for the Swat and Kabul sub‐basins. The Chitral sub‐basin received rising precipitation in spring, summer, and autumn, whereas no trend was observed during winter. In the southern Himalayas (Kanshi and Jhelum), no trend was observed in winter and autumn and a falling trend in spring and summer. The Kunhar sub‐basin (southern Himalaya) showed rising trends in winter, spring, and autumn. In contrast, the Soan sub‐basin (eastern Himalaya) has no trend in spring, and other seasons show rising trends. The sub‐basin Upper Indus experienced a rising trend for autumn, winter, and summer, while a downward trend was observed in spring. The IPTA and ITA approaches are much more sensitive than the Mann–Kendall method in detecting trends. Although the innovative methods are mostly compatible with each other (90%), the IPTA presents additional information about trend transitions between successive parts of the time series. The results presented in this study are an advancement in the investigations made so far in this region and will help to understand the climate and hydrology of this region.

Climate change simulation and trend analysis of extreme precipitation and floods in the mesoscale Rur catchment in western Germany until 2099 using Statistical Downscaling Model (SDSM) and the Soil & Water Assessment Tool (SWAT model).

Due to climate change and global warming, speed and intensity of the hydrological cycle will accelerate. In order to carry out regional risk assessment, integrated water resources management and flood protection, far reaching predictions and future scenarios of climate change effects on extreme precipitation and flooding are of particular relevance. In this study, trends in frequencies of extreme precipitation and floods until 2099 are analysed for the German Rur catchment, which is half located in highlands and half in lowlands and therefore has a high topographical and climatological contrast. To predict future trends, coupled modeling is performed based on NCEP reanalysis data and a General Circulation Model (GCM). Assuming HadCM3 future emission scenarios A2a and B2a, an empirical Statistical Downscaling Model (SDSM) is developed and daily precipitation amounts are projected until 2099 by a stochastic weather generator. The generated precipitation data are used as an input for the ecohydrological Soil & Water Assessment Tool (SWAT model) to simulate daily water discharge until 2099. Statistical trend analyses are implemented based on three annual extreme precipitation indices (EPIs) and the magnitudes of ten flood return periods derived with GEV and Gumbel extreme value distributions for 109 30-year moving periods using regression analyses and Mann-Kendall tendency tests to check for significant trends in the frequencies until 2099. As a result, it could be demonstrated for all EPIs that the frequency of extreme precipitation in the upper Rur catchment will significantly increase by +33% to +51% until 2099 compared to the base period 1961-1990, whereas mostly non-significant negative trends of extreme precipitation can be projected in the lowlands. For runoff, it was found that the magnitudes of the ten flood return periods will significantly increase by +31% for B2a to +36% for A2a until 2099 compared to the base period.

Analysis of Precipitation and Temperature Trends Under the Impact of Climate Change Over Ten Districts of Jimma Zone, Ethiopia

Analysis of Precipitation and Temperature Trends Under the Impact of Climate Change Over Ten Districts of Jimma Zone, Ethiopia

Comparison of Statistical Methods to Graphical Method in Precipitation Trend Analysis, A Case Study: Coruh Basin, Turkey

Comparison of Statistical Methods to Graphical Method in Precipitation Trend Analysis, A Case Study: Coruh Basin, Turkey

Homogeneity of Çanakkale Precipitation Observation Stations and Trend Analysis of Annual Precipitation

Coğrafi bölge olarak Marmara Bölgesinde bulunan ve genel anlamda Akdeniz iklimi özelliklerini yansıtan Çanakkale ili yağış eğiliminin, gidişatının ve sıklığının analiz edildiği bu çalışmada 21 yağış gözlem istasyonunun 1929-2020 yılları arası kaydedilen yıllık toplam yağış verileri kullanılmıştır. İlk olarak istasyonların eksik verileri enterpole edilerek kayıp yıllar tamamlanmış ve SNHT, Pettitt, Buishand, Von-Neuman testi olmak üzere 4 farklı homojenlik testi ile sınanmıştır. Yağış gözlem istasyonlarının Mann-Kendall Testi, Mann-Kendall Mertebe Korelâsyon Testi, Sen’in Eğilim Testi ve Şen’in Yenilikçi Eğilimi ile test edilmesi sonucunda 4 testin aynı trend sonucunu vermesiyle birlikte 6 ilçede eğilim kesin olarak saptanmıştır. Ayvacık, Çan, Eceabat, Ezine ve Lapseki ilçesinde artış eğilimi; Biga ilçesinde ise azalış eğilimi belirgin bir şekilde ortaya konulmuştur. Kalan 6 ilçede ise test sonuçları belirgin bir şekilde değerlendirilmeyip çoğunluk durumuna göre belirlenmiştir. Bu duruma göre Bozcaada ve Yenice ilçelerinde artış eğilimi, Bayramiç ve Gelibolu ilçelerinde azalış eğilimi tespit edilmiştir. Merkez ve Gökçeada ilçesinde ise herhangi bir artan veya azalan eğilime rastlanılmamıştır.

Spatio-temporal trend analysis and future projections of precipitation at regional scale: a case study of Haryana, India

Abstract In this study, we investigated the spatio-temporal distribution and performance of seasonal precipitation in all districts of Haryana, India. We analysed the gridded precipitation dataset of the India Meteorological Department (IMD) for a period of 120 years (1901–2020) using different statistical methods. We found that Haryana received a mean precipitation of 37.0, 37.7, 468.3, and 24.8 mm during the winter, pre-monsoon, monsoon, and post-monsoon seasons, respectively. During each season, the eastern districts of Haryana received more precipitation than its western counterparts. Sen's slope results obtained after trend-free pre-whitening (TFPW) showed a statistically significant increasing trend of 0.12 mm (p-value; 0.04) during the pre-monsoon period, whereas decreasing but non-significant trends were observed during the winter, monsoon and post-monsoon seasons at the rate of −0.04 mm (p-value; 0.49), −0.26 mm (p-value; 0.52), −0.05 mm (p-value; 0.33) per year, respectively, for the entire Haryana state. The winter precipitation is expected to increase under the Representative Concentration Pathway 4.5 (RCP4.5) scenario, whereas pre-monsoon precipitation is expected to decrease under the RCP8.5 scenario by the end of the 21st century. The monsoon precipitation is expected to decrease under all RCP scenarios, whereas post-monsoon precipitation is expected to gradually increase under the RCP8.5 scenario by the end of the 21st century.

Long period trend analysis of precipitation and temperature of west Sikkim, India

The present study aims to analyse the long period trend of precipitation and temperature in West district of Sikkim, India. For this purpose daily precipitation and temperature data of more than 100 years were extracted from the gridded dataset provided by the India Meteorological Department, Government of India. Long-term monthly, annual and seasonal trend of precipitation and temperature have been analysed and results show declining trend of monsoonal and annual precipitation as revealed by Sen’s slope estimator, whereas increasing trend of temperature since 1950s. Rate of change of mean annual temperature is 0.027 °C per year for the period of 1901-2014.

Анализ климатических переменных в верховьях бассейна реки Амударья в Таджикистане

This article presents the results of the trend analysis of precipitation, maximum and minimum temperatures in the upstream of Amu Darya River Basin in Tajikistan. The result showed that in the south part of Tajikistan the trend of the summer and winter seasons indicate a positive and the temperature rises in summer and winter. In the north and central part of Tajikistan, there is also a positive trend in summer and winter with the exception of the Rasht and Murgab stations, where was recorded a decreasing trend in air temperature in summer. The eastern part of Tajikistan, where the high-altitude territory begins, the temperature trend shows that the summer period of the year becomes slightly cooler, and the winter period shows an increasing temperature trend, i.e. it is getting warmer. On the flat plain areas of Tajikistan, a relative increase in precipitation is observed, and the amount of precipitation in the high-mountain zone (eastern Pamir) decreases according to long-term data. This study shows pronounced climatic fluctuations in Tajikistan, changes in air temperature and precipitation conditions.

Climate Change and Overuse: Water Resource Challenges during Economic Growth in Coquimbo, Chile

The arid Coquimbo region of Chile has experienced a significant economic growth in recent decades, fueled in large part by water-intensive activities such as mining and agriculture. Under this context, a monthly and annual trend analysis of precipitation, streamflow, and piezometric levels was carried out. Thus, 43 pluviometric stations, 11 fluviometric stations, and 11 wells were selected. These stations were evaluated for their temporal trends using the Mann–Kendall test. Results revealed a significant decrease in river flows, with negative and significant trends concentrated in the mean and maximum flows, both at annual and monthly levels. Likewise, positive trends were found in the depth to water table on wells, with significant trends in 81.8% of the monthly cases, and in 72.7% of the annual cases. While also decreasing over the same period, rainfall trends exhibit high variability and lacked significance. Although the amounts of precipitation have decreased, this does not seem to be the main factor responsible for the scarcity of water in the region, but rather an excessive consumption of this resource. This is endorsed by the increase in GDP (Gross Domestic Product), which is explained by activities that consume water (mining and agriculture). Similarly, an increase in the granting of underground water rights was verified, which speaks of the high demands for the resource. However, future modeling is advised to better understand the regional hydrology of the area and quantify the anthropic effects on water resources more precisely.

Temperature and precipitation trend analysis of the Iraq Region under SRES scenarios during the twenty-first century

Temperature and precipitation trend analysis of the Iraq Region under SRES scenarios during the twenty-first century