Trend Analysis Of Precipitation Research Articles

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

ÇANAKKALE YAĞIŞ GÖZLEM İSTASYONLARININ HOMOJENLİK DURUMU VE YILLIK YAĞIŞLARIN TREND ANALİZİ

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

Water security assessment in ungauged regions using the water balance and water footprint concepts and satellite observations

AbstractWater security assessments often rely on outputs from hydrological models that are applicable only in gauged regions where there are river discharge data to constrain the models. Therefore, there is an urgent need to explore new methods for assessing water security in ungauged regions. This study proposes the use of the water balance and water footprint concepts and satellite observations to assess water security in Anglophone Cameroon, which is an example of a typically ungauged region. Specifically, the study assesses demand-driven water scarcity in terms of blue and green water scarcities and population-driven water scarcity quantified using the Falkenmark index across all districts in Anglophone Cameroon. The study also performs a spatiotemporal trend analysis of precipitation and temperature in the study area using the Mann–Kendall test. Precipitation trend analysis returns varying strengths and magnitudes for different districts unlike temperature which demonstrates an upward trend in all districts. The water security assessment shows that blue water scarcity is substantially low across most districts, whereas population-driven water scarcity is observed in densely populated districts (<1,700 m3/capita/year). The results from this study suggest that the proposed method may be used to assess water security in ungauged regions irrespective of climate or population size.

Unravelling Precipitation Trends in Greece since 1950s Using ERA5 Climate Reanalysis Data

Precipitation is one of the most variable climatic parameters, as it is determined by many physical processes. The spatiotemporal characteristics of precipitation have been significantly affected by climate change during the past decades. Analysis of precipitation trends is challenging, especially in regions such as Greece, which is characterized by complex topography and includes several ungauged areas. With this study, we aim to shed new light on the climatic characteristics and inter-annual trends of precipitation over Greece. For this purpose, we used ERA5 monthly precipitation data from 1950 to 2020 to estimate annual Theil–Sen trends and Mann–Kendall significance over Greece and surrounding areas. Additionally, in order to analyze and model the nonlinear relationships of monthly precipitation time series, we used generalized additive models (GAMs). The results indicated significant declining inter-annual trends of areal precipitation over the study area. Declining trends were more pronounced in winter over western and eastern Greece, but trends in spring, summer and autumn were mostly not significant. GAMs showcased that the trends were generally characterized by nonlinearity and precipitation over the study area presented high inter-decadal variability. Combining the results, we concluded that precipitation did not linearly change during the past 7 decades, but it first increased from the 1950s to the late 1960s, consequently decreased until the early 1990s and, afterwards, presented an increase until 2020 with a smaller rate than the 1950–1960s.

Application of non-parametric innovative trend analysis of different time scale precipitation during (1951–2016) in Khyber Pakhtunkhwa, Pakistan

Application of non-parametric innovative trend analysis of different time scale precipitation during (1951–2016) in Khyber Pakhtunkhwa, Pakistan

Analysis of Precipitation Trends and Prediction in Selected Cities in the Southeast Louisiana

The impacts of climate change are being felt in Louisiana, in the form of changing weather patterns that have resulted in changes in floods, hurricanes, tornadoes frequencies of occurrence, and magnitudes, among others resulting in, flooding. The variabilities in rainfall in a drainage basin affect water availability and sustainability. This study analyzed the precipitation data of Southeastern Louisiana, United States, for the period 1990 to 2020. Data used in the study was from, Donaldsonville, Galliano, Lafourche, Gonzales, Ascension, Morgan, New Orleans, Audubon, Plaquemine, and Ponchatoula, Tangipahoa, weather stations. These stations were selected because the differences between each of their highest and lowest average annual rainfall data were greater than 20 inches. To investigate climate patterns and trends for the given weather stations in Southeastern Louisiana, precipitation data were analyzed on annual time scales using data collected from the World Bank Group Climate Change Knowledge Portal for Development Practitioners and Policy Makers and the Applied Climate Information System (ACIS) of the National Weather Service Prediction Center. The data were further aggregated using annual average blocks of 4 years, and linear and polynomial regression was performed to establish trends. The highest and lowest average annual rainfall data for Donaldsonville, Galliano, Lafourche, Gonzales, Ascension, Morgan, New Orleans, Audubon, Plaquemine, and Ponchatoula, Tangipahoa, weather stations were, 75 and 48, 71 and 44, 73.5 and 52.7, 75 and 46.4, 72 and 41.3, 94 and 55.3, Ponchatoula, and 78.6 and 44, respectively. Plaquemine recorded the highest average annual average rainfall while New Orleans, Audubon station recorded the lowest. The projection of the precipitation in 2030 has been carried out to inform scientists and stakeholders about the approximate quantity of rainfall expected and enable them to make their expected impacts on agriculture, economy, etc. The precipitation for 2030 was predicted by extrapolating models for the weather stations. The data used for the modeling was selected based on the data entries most representative. Hence, the coefficient of correlation and the number of data entries were both considered. Extrapolating results for 2030 precipitation in Donaldsonville, Galliano, Gonzales, Morgan, New Orleans, Audubon, and Plaquemine were found to be within the ranges, (85.6 - 86.7), (75.55 - 76.60), (89.7 - 90.67), (99.9 - 100.5), (71.68 - 72.66), and (107.7 - 108.8) inches, respectively. Hence, the average annual precipitations in areas covered by these stations except for Plaquemine station are expected to significantly increase. A restively low increase in average precipitation is expected for Plaquemine station. The increase could impact agriculture negatively or positively depending on the crop’s soil moisture tolerance.

Spatio-temporal trend and frequency analysis of precipitation in South-southern Nigeria (SSN)

Precipitation is one of the key climatic parameters that have a significant impact on the spatial and temporal trends of available water resources in a region. Therefore, carrying out a long-term analysis on its seasonal and annual trends and variability is imperative for viable water resources management. This study investigates the seasonal and annual precipitation data for South-southern Nigeria (SSN) between 1951 and 2016. Over the 66 yr period, SSN witnessed a region-wide decrease in annual and DJF, MAM and JJA seasonal precipitation; while in SON, precipitation was reduced in 81.2% of the stations. On the regional level, station-specific trend analysis confirmed a region-wide decrease; however, a greater number of significant declines were found for annual and MAM precipitation records for all 6 states within SSN. The degree of wetness and dryness within the states indicate that all experienced more periods of extreme dryness than extreme wetness during the study duration. This may be attributed to evident changes in climate that are also reflected in the decreasing trends reported for the annual and seasonal timescales. The only significant cycle was detected at 1 yr timescale throughout the study period for precipitation time series in all the six states in SSN.. The major results of this study show that SSN may have challenges in securing the water required for agriculture and other domestic needs if adequate measures are not in place to fully harness other water sources within the crop-growing season of MAM.

Observed climate changes in the Toplica river valley : Trend analysis of temperature, precipitation and river discharge

Changes in air temperature, precipitation, and the Toplica river discharge were investigated. Annual and seasonal climatic data were collected at weather stations Kursumlija and Prokuplje, and discharge data on hydrological gauges Pepeljevac and Doljevac. The data covered a period of 62 years (1957–2018). Mann-Kendall and Pettitt’s tests have been applied for the periods 1957–2018, 1957–1987, 1988–2018, and 1975–1994, which we find as very important period when atmospheric circulation was altered. Mean annual temperature and precipitation were greater in the second half-period, while the discharge was smaller, even all the signals had growth trend. Mean seasonal temperature increased for all seasons, as well as precipitation, except for summer (JJA). The discharge is lower in the second half-period for almost all seasons, with signs of recovery for all seasons except summer.

Drought Monitoring and Assessment of Climate Parameters Variability in Koutiala and San Districts, Mali

In Mali, the annual temperature, rainfall, and evapotranspiration are high variables. Their distributions are unevenly spread from north to south. Climate change strengthens to increase air temperature and evapotranspiration. It also increases the intense rainstorms and the risk of drought associated heat waves. Drought is considered a natural disaster among all hydrologic extremes. It causes severe damage to the environment, agriculture, and livelihoods relying on water resources. The present study evaluated the variation of drought indices from 1989 to 2019 in Koutiala and San districts, respectively. Therefore, the Standardized Precipitation Evapotranspiration Index (SPEI) was applied. Hence, the Mann-Kendall (MK) test was used and for 12-month time-scales. Trend analysis of monthly precipitation, temperature, and evapotranspiration has been done by using the MK test. Based on the analysis result, the climate of the Koutiala and San districts has been classified as moderate to severe drought category. However, this result clearly shows SPEI pattern changes in both districts. The monthly precipitation showed a significant decreasing trend in Koutiala and San districts. In comparison, the monthly temperature and evapotranspiration displayed an increasing trend in both districts.

Influence of meteorological drought on environmental flows in mountain catchments

This study investigates the course of atmospheric drought to the response of the water resources availability taking into account the constraints arising from the need to maintain adequate environmental flows (e-flow) releases. For that purpose, eight catchments of southern Poland, namely, Skawa and Dunajec sub-basins (i.e., upper Vistula basin), were considered as study cases. The analysis was carried out as follows: trend analysis of streamflow rate and mean annual precipitation; determination of e-flows using the following methods: 25% mean multi-year flow (25%MAF), the minimum acceptable flow determined by Kostrzewa's method (Qn), the median of monthly mean flows (Qmed), flow with a guarantee of 90% (Q90%), and minimum mean 7-day flow with a recurrence period of 2 years (7Q2). The standardized precipitation index (SPI) and normal precipitation index (PNI) were used as meteorological drought indices to determine the relationship between meteorological drought and e-flow releases. The results revealed a lack of significant trends in annual precipitation and a significantly decreasing trend of streamflow rate in the Skawa sub-basin. For the Dunajec sub-basin, the significantly decreasing trend in streamflow was detected only for Biała; a significant increasing trend was for Biała and Sękówka catchments. The highest values of e-flows were obtained for Qmed and the lowest for 7Q2. The SPI values resulting from the multi-year analysis show that most of the period was dominated by meteorological drought. According to PNI values, the dominant period was normal years. Extremely wet years were found sporadically and were triggered by extremely high precipitation over southern Poland, like in 2010. The results demonstrate that the highest correlations between the SPI, PNI, and e-flows were obtained for 25%MAF and Qmed. Moreover, results exhibited a weak correlation between SPI, PNI values, streamflow rate, and a medium to high correlation for e-flows. The findings from this study showed that SPI and PNI indices could be a helpful tool in water resources management and planning, especially in predicting the influence of droughts on the e-flows deficit.

Innovative trend analysis of annual precipitation in Serbia during 1946–2019

Innovative trend analysis of annual precipitation in Serbia during 1946–2019

Variability and trend analysis of precipitation during 1961-2015 in Southwest Guizhou Autonomous Prefecture (SGAP), China

Information on variability and trends of precipitation over a region is useful in the agricultural production management. The linear regression analysis, 5-year moving average, accumulated anomaly and Mann-Kendall trend detection were used to assess the variability and trends in precipitation over Southwest Guizhou Autonomous Prefecture (SGAP) region of China. The results revealed that the annual precipitation showed an increasing trend at Wangmo and Xingren and decreasing trends at Anlong, Ceheng, Pu’an, Qinglong, Xingyiand Zhenfeng stations. The UF(k) and UB(k) curves of each region have intersections, except in Ceheng and Xingren, and this indicated that the precipitation has seen a abrupt change in six stations. The results of this study will provide theoretical guidance for agricultural water management in Southwest Guizhou Autonomous Prefecture of China.

Drought identification and analysis of precipitation trends in Beed District, Maharashtra

Drought is a complex natural hazard with slow-onset and can occur over months or even years. Typically, a drought index is used to quantify the effect of drought which is based on various meteorological parameters, most importantly precipitation. However, the changing pattern of the rainfall is now a concerning issue and therefore, trend analysis of the precipitation data has become a vital part of the study, as it gives important information of the possibility of changes before prediction and analysis of natural hazards like drought. In the present study, spatial and temporal assessment of meteorological drought has been carried out for the Beed district of the Marathwada region, which is known as a drought-prone area in Maharashtra state. Initially, trend analysis of 34 years of precipitation data has been carried out using non-parametric tests Man-Kendall and Sen’s slope estimator. The beginning and end of the trend is determined using sequential Mann-Kendall test. Then, standardized precipitation index (SPI) values of different timescales (1, 3, 6, 9, and 12-monthly) were used to identify and analyze the drought events. The evaluation of the spatial distribution of the SPI over the region has been carried out using GIS. The results of trend analysis revealed that the East and West Beed region station shows non-significant decreasing trends while Central Beed shows a non-significant increasing trend for the monsoon season (June to September). The study has identified a total of six drought events (1985–86, 1987–88, 1992–93, 2001–02, 2005–06, and 2011–12) from 1979 to 2013. The results of the study show that Jamkhed, Ashti, Majalgaon, and Ambejogai are the most affected areas, whereas, Georai and Beed are the least affected during the drought events. The findings of present study will be helpful to gain a better understanding of the drought situation through in-depth trend analysis of precipitation, and assisting policymakers in developing a drought management plan to address the water related crisis.