scholarly journals Rainfall Trends over the Past Century for Tropical Climatic Region in Western India

10.29007/szsv ◽  
2018 ◽  
Author(s):  
Priyank Sharma ◽  
Prem Lal Patel

Present study examines the applications of different trend detection methodologies for investigation of trend in long-term rainfall over Lower Tapi basin, India using daily gridded rainfall data for the period 1901 – 2013 at 0.25  0.25 resolution. The trends in rainfall indices, viz. total annual rainfall (TAR), annual maximum rainfall (AMR) and average annual rainfall intensity (AAI) have been detected using non-parametric and graphical methods. The results show increasing trends in TAR across all the 9 grids in the study region, with significant increasing trend over Grids-8 and 9. Further, AMR exhibited increasing trend over 7 out of 9 grids, with significant increasing trend over Grid-8 (ZMMK = 2.478;  = 0.356 mm/year) and Grid-9 (ZMMK = 2.278;  = 0.257 mm/year). The Innovative Trend Analysis plots reveal overall increasing trend in AMR across all the grids. The AAI exhibited significant increasing trend over 5 grids including Grids-8 and 9. The Grids 8 and 9 encompass the urban areas of the Surat city, located in the Lower Tapi basin. The urbanization in the Surat city and proximity to the Arabian Sea areas may be the possible reasons for significant increase in the extreme rainfall and rainfall intensity over Grids-8 and 9.

Changing Climate is one of the most significant ecological issue, with the implications for agricultural production, water resource, energy and some other aspects of human well-being. Analysis of changing climate is important to assess climate-induced changes through the analysis of variability of climatic parameters such as temperature, precipitation, runoff and groundwater to suggest feasible adaptation strategies. This paper aims the long-term variability of rainfall and temperature using gridded daily data obtained from India Meteorological Department with 0.250 resolution from 1901-2016 for precipitation and 10 resolution from 1969-2005 for temperature (re-gridded to IMD 0.250 gridded location) in Ghataprabha sub basin (K3) of Krishna basin. The analysis of variability and trend in precipitation and temperature carried out by using coefficient of variation (CV), rainfall and temperature anomaly and also Mann-Kendall (MK) test was used to detect the time series trend. Statistical analysis of variability and trend in annual, Indian Summer Monsoon (ISMR) rainfall and temperature observed that i) there is an intra and inter annual variability of precipitation in the sub basin ii) test results revealed that the annual and ISMR trend appears to be increased by 0.12 & 0.14, iii) the Mann-Kendal trend test also analysed for annual minimum, mean and maximum temperature over the K3 sub basin (1969-2005) shows increasing trend by 0.06, 0.21 and 0.40. This analysis revealed that, there is an increasing trend in annual rainfall and temperature observed over the study region.


Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 347 ◽  
Author(s):  
Hanane Bougara ◽  
Kamila Baba Hamed ◽  
Christian Borgemeister ◽  
Bernhard Tischbein ◽  
Navneet Kumar

Northwest Algeria has experienced fluctuations in rainfall between the two decades 1940s and 1990s from positive to negative anomalies, which reflected a significant decline in rainfall during the mid-1970s. Therefore, further analyzing rainfall in this region is required for improving the strategies on water resource management. In this study, we complement previous studies by dealing with sub basins that were not previously addressed in Tafna basin (our study area located in Northwest Algeria), and by including additional statistical methods (Kruskal–Wallis test, Jonckheere-Terpstra test, and the Friedman test) that were not earlier reported on the large scale (Northwest Algeria). In order to analyse the homogeneity, trends, and stationarity in rainfall time series for nine rainfall stations over the period 1979–2011, we have used several statistical tests. The results showed an increasing trend for annual rainfall after the break detected in 2007 for Djbel Chouachi, Ouled Mimoun, Sidi Benkhala stations using Hubert, Pettitt, and Buishand tests. The Lee and Heghinian test has detected a break at the same year in 2007 for all stations except Sebdou, Beni Bahdel, and Hennaya stations, which have a break date in 1980. We have confirmed this increasing trend for rainfall with other trend detection methods such as Mann Kendall and Sen’s method that highlighted an upward trend for all the stations in the autumn season, which is mainly due to an increase in rainfall in September and October. On a monthly scale, the date of rupture is different from one station to another because the time series are not homogeneous. In addition, we have applied three tests enabling further results: (i) the Jonckheere-Terpstra test has detected an upward trend for two stations (Khemis and Hennaya), (ii) Friedman test has indicated the difference between the mean rank again with Khemis and Hennaya stations and the Merbeh station, (iii) according to the Kruskal-Wallis test, there have been no variance detected between all the rainfall stations. The increasing trend in rainfall may lead to a rise in stream flow and enhance potential floods risks in low-lying regions of the study area.


2019 ◽  
Vol 34 (2) ◽  
pp. 247-254
Author(s):  
Luciele Vaz da Silva ◽  
Derblai Casaroli ◽  
Adão Wagner Pêgo Evangelista ◽  
José Alves Júnior ◽  
Rafael Battisti

Abstract The region of study was MATOPIBA, located in the north of Brazilian Savanna biome (Cerrado), encompassing part of north/northeast of Brazil. The region has been gaining prominence in the last years due to the expansion of agricultural over this area. The aims of this study were: to adjust parameters for rainfall intensity-duration-frequency; and to identify the most vulnerable agricultural areas to erosion based on erosivity and erodibility. The rainfall intensity-duration-frequency function were adjusted using series of maximum annual rainfall event from 105 rainfall gauges. Gumbel model was the most efficient to simulate the maximum rainfall intensity, where these data were used to adjusted the rainfall intensity-duration-frequency model based on K, a, b and c parameters. The most rainfall gauges showed intensity between 51 and 80 mm h-1 and 81 and 120 mm h-1, respectively, for return period of 2 and 100 years with rainfall duration of 30 minutes. The higher rainfall intensity was observed mainly in the central-north of the region associated with rainfall systems. The rainfall intensity showed a huge capacity to cause soil erosion based on the erosivity energy, while the moderate erodibility was observed for areas with Ferralsols and Leptosols and low erodibility for areas with Arenosols.


Hydrology ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 32 ◽  
Author(s):  
Adam Repel ◽  
Vinayakam Jothiprakash ◽  
Martina Zeleňáková ◽  
Helena Hlavatá ◽  
Ionut Minea

The aim of this paper is the application of temporal analysis of daily and 10 min of rainfall data from Poprad station, located in Eastern Slovakia. There are two types of data used in the analysis, firstly, a daily time step data, manually collected between the years 1951 and 2018 and secondly, 10 min of data, automatically collected between the years 2000 and 2018. For proper comparability, the automatically collected data has been recalculated to the daily form. After a comparison of the sets of data, manually collected daily data has been used in further analysis. The main analysis can be divided into two sections. The first section consists of basic statistics (mean, standard deviation, etc.) and the second section of descriptive statistics, where the subjects of examination were trend, stationarity, homogeneity, periodicity and noise. The results of the basic statistics outlined trend behavior in the data meaning that the annual total rainfall for the period 1951–2018 is slightly increasing but the further investigation supported by the methods of descriptive statistics refuted this thesis. The number of rainy days is decreasing but maximum rainfall intensity is increasing year by year, indicating that total rainfall is happening in lesser and lesser days, with an increase in the number of 0 rainfall days. The results demonstrated no presence of the trend or only a weak trend in daily time step, but a significant increasing trend in annual rainfall. Tests of stationarity proved that the data are stationary and, therefore, suitable for any hydrologic analysis. The tests of homogeneity showed no breakpoints in the data. The interesting result was demonstrated by the periodicity test, which showed exactly a 365.25 days’ period, while 0.25 indicates a leap year. As a summary for the Poprad station, there is no tendency of increasing of daily average rainfall, but slight increasing trend of total annual rainfall, the summer season has the highest ratio on total precipitation per year, September and October are the months with the highest numbers of days without rain.


Author(s):  
Viviane R. Dorneles ◽  
Rita de C. F. Damé ◽  
Claudia F. A. Teixeira-Gandra ◽  
Letícia B. Méllo ◽  
Mario A. A. Ramirez ◽  
...  

ABSTRACT Rainfall intensity-duration-frequency (IDF) relationships are a tool that can be used in modeling the transformation of rainfall to runoff, required for the design of hydraulic works. The objective of this study was to verify if there is a significant difference between the intensity-duration-frequency relationships generated using pluviographic records and those determined from pluviometric data. Maximum annual rainfall intensity values were obtained from the disaggregation of maximum daily rainfall and rainfall records in the durations of 5, 10, 15, 20, 30, 60, 120, 360, 720 and 1440 min and for the return periods of 2, 5, 10, 20, 25, 50 and 100 years, in the locality of Pelotas, Rio Grande do Sul state, Brazil (31° 46’ 34’’ S; 52° 21’ 34’’ W, altitude of 13.2 m). By Student’s t-test, it was verified that there is no significant difference between the values of maximum rainfall intensity obtained from pluviographic records and those determined from pluviometric data.


2016 ◽  
Vol 11 (2) ◽  
pp. 567-576 ◽  
Author(s):  
S Thangamani ◽  
A Raviraj

The present study attempted to find out the relation between rainfall variability, trend and distribution in Dindigul district of Amaravathi basin for groundwater management. A detailed analysis of monthly, seasonal and spatial variation of rainfall (1971-2014) for the study area had carried out. The normal annual rainfall of the district varies from 700 to 1600 mm. The north east monsoon contributed the maximum rainfall of 439mm (50%), followed by South-west monsoon which contributed 254 mm (29%), summer which contributed 147 mm (16.8%) and winter contributed the minimum rainfall of 26.8 mm (2.8%).A high value of CV had observed in all the stations, which indicate the greater rainfall variability, and more chances of occurrence of drought. Higher variability of coefficient of variation was observed in central part of the district.Theresult of MMK z-test at 1% level indicates that the majority of stations showed non-significant trend in annual, summer and monsoon season of rainfall. Out of the 13 stations studied in the district, annual rainfall of only one station (Kuthiraiyar) showed significant decreasing trend in annual rainfall (-3.05 mm/year) and five stations recorded the significant decreasing trend in rainy days during southwest monsoon. Chatrapatti and Natham stations recorded the significant increasing trend during north east monsoon and Virupatchi station recorded the decreasing trend.


2010 ◽  
Vol 11 (1) ◽  
pp. 26-45 ◽  
Author(s):  
Nityanand Singh ◽  
Ashwini Ranade

Abstract Characteristics of wet spells (WSs) and intervening dry spells (DSs) are extremely useful for water-related sectors. The information takes on greater significance in the wake of global climate change and climate-change scenario projections. The features of 40 parameters of the rainfall time distribution as well as their extremes have been studied for two wet and dry spells for 19 subregions across India using gridded daily rainfall available on 1° latitude × 1° longitude spatial resolution for the period 1951–2007. In a low-frequency-mode, intra-annual rainfall variation, WS (DS) is identified as a “continuous period with daily rainfall equal to or greater than (less than) daily mean rainfall (DMR) of climatological monsoon period over the area of interest.” The DMR shows significant spatial variation from 2.6 mm day−1 over the extreme southeast peninsula (ESEP) to 20.2 mm day−1 over the southern-central west coast (SCWC). Climatologically, the number of WSs (DSs) decreases from 11 (10) over the extreme south peninsula to 4 (3) over northwestern India as a result of a decrease in tropical and oceanic influences. The total duration of WSs (DSs) decreases from 101 (173) to 45 (29) days, and the duration of individual WS (DS) from 12 (18) to 7 (11) days following similar spatial patterns. Broadly, the total rainfall of wet and dry spells, and rainfall amount and rainfall intensity of actual and extreme wet and dry spells, are high over orographic regions and low over the peninsula, Indo-Gangetic plains, and northwest dry province. The rainfall due to WSs (DSs) contributes ∼68% (∼17%) to the respective annual total. The start of the first wet spell is earlier (19 March) over ESEP and later (22 June) over northwestern India, and the end of the last wet spell occurs in reverse, that is, earlier (12 September) from northwestern India and later (16 December) from ESEP. In recent years/decades, actual and extreme WSs are slightly shorter and their rainfall intensity higher over a majority of the subregions, whereas actual and extreme DSs are slightly (not significantly) longer and their rainfall intensity weaker. There is a tendency for the first WS to start approximately six days earlier across the country and the last WS to end approximately two days earlier, giving rise to longer duration of rainfall activities by approximately four days. However, a spatially coherent, robust, long-term trend (1951–2007) is not seen in any of the 40 WS/DS parameters examined in the present study.


2016 ◽  
Vol 144 (16) ◽  
pp. 3422-3425 ◽  
Author(s):  
P. SINGH ◽  
M. CHHABRA ◽  
P. SHARMA ◽  
R. JAISWAL ◽  
G. SINGH ◽  
...  

SUMMARYCrimean-Congo haemorrhagic fever (CCHF) is an emerging zoonotic disease in India which is prevalent in neighbouring countries. CCHF virus (CCHFV) is a widespread tick-borne virus which is endemic in Africa, Asia, Eastern Europe and the Middle East. In the present study, samples of clinically suspected human cases from different areas of northern-western India were tested for the presence of CCHFV by RT–PCR through amplification of nucleocapsid (N) gene of CCHFV. Positive samples were sequenced to reveal the prevailing CCHFV genotype(s) and phylogenetic relatedness. A phylogenetic tree revealed the emergence of diverse strains in the study region showing maximum identity with the Pakistan, Afghanistan and Iran strains, which was different from earlier reported Indian strains. Our findings reveal for the first time the emergence of the Asia 1 group in India; while earlier reported CCHFV strains belong to the Asia 2 group.


2008 ◽  
Vol 12 (2) ◽  
pp. 523-535 ◽  
Author(s):  
M. López-Vicente ◽  
A. Navas ◽  
J. Machín

Abstract. The Mediterranean environment is characterized by strong temporal variations in rainfall volume and intensity, soil moisture and vegetation cover along the year. These factors play a key role on soil erosion. The aim of this work is to identify different erosive periods in function of the temporal changes in rainfall and runoff characteristics (erosivity, maximum intensity and number of erosive events), soil properties (soil erodibility in relation to freeze-thaw processes and soil moisture content) and current tillage practices in a set of agricultural fields in a mountainous area of the Central Pyrenees in NE Spain. To this purpose the rainfall and runoff erosivity (R), the soil erodibility (K) and the cover-management (C) factors of the empirical RUSLE soil loss model were used. The R, K and C factors were calculated at monthly scale. The first erosive period extends from July to October and presents the highest values of erosivity (87.8 MJ mm ha−1 h−1), maximum rainfall intensity (22.3 mm h−1) and monthly soil erosion (0.25 Mg ha−1 month−1) with the minimum values of duration of erosive storms, freeze-thaw cycles, soil moisture content and soil erodibility (0.007 Mg h MJ−1 mm−1). This period includes the harvesting and the plowing tillage practices. The second erosive period has a duration of two months, from May to June, and presents the lowest total and monthly soil losses (0.10 Mg ha−1 month−1) that correspond to the maximum protection of the soil by the crop-cover ($C$ factor = 0.05) due to the maximum stage of the growing season and intermediate values of rainfall and runoff erosivity, maximum rainfall intensity and soil erodibility. The third erosive period extends from November to April and has the minimum values of rainfall erosivity (17.5 MJ mm ha−1 h−1) and maximum rainfall intensity (6.0 mm h−1) with the highest number of freeze-thaw cycles, soil moisture content and soil erodibility (0.021 Mg h MJ−1 mm−1) that explain the high value of monthly soil loss (0.24 Mg ha−1 month−1). The interactions between the rainfall erosivity, soil erodibility, and cover-management factors explain the similar predicted soil losses for the first and the third erosive periods in spite of the strong temporal differences in the values of the three RUSLE factors. The estimated value of annual soil loss with the RUSLE model (3.34 Mg ha−1 yr−1) was lower than the measured value with 137Cs (5.38 Mg ha−1 yr−1) due to the low values of precipitation recorded during the studied period. To optimize agricultural practices and to promote sustainable strategies for the preservation of fragile Mediterranean agrosystems it is necessary to delay plowing till October, especially in dryland agriculture regions. Thus, the protective role of the crop residues will extend until September when the greatest rainfall occurs together with the highest runoff erosivity and soil losses.


2013 ◽  
Vol 17 (7) ◽  
pp. 2859-2871 ◽  
Author(s):  
D. H. Yan ◽  
D. Wu ◽  
R. Huang ◽  
L. N. Wang ◽  
G. Y. Yang

Abstract. Abrupt drought–flood change events caused by atmospheric circulation anomalies have occurred frequently and widely in recent years, which has caused great losses and casualties in China. In this paper, we focus on investigating whether there will be a rainfall occurrence with higher intensity after a drought period in the Huang–Huai–Hai River basin. Combined with the Chinese climate divisions and the basin's DEM (digital elevation model), the basin is divided into seven sub-regions by means of cluster analysis of the basin meteorological stations using the self-organizing map (SOM) neural network method. Based on the daily precipitation data of 171 stations for the years 1961–2011, the changes of drought times with different magnitudes are analyzed, and the number of consecutive days without precipitation is used to identify the drought magnitudes. The first precipitation intensity after a drought period is analyzed with the Pearson-III frequency curve, then the relationship between rainfall intensity and different drought magnitudes is observed, as are the changes of drought times for different years. The results of the study indicated that the occurrence times of different drought levels show an overall increasing trend; there is no clear interdecadal change shown, but the spatial difference is significant. (2) As the drought level increases, the probability of extraordinary rainstorm becomes lower, and the frequency of occurrence of spatial changes in different precipitation intensities vary. In the areas I and II, as the drought level increases, the occurrence frequency of different precipitation intensities first shows a decreasing trend, which becomes an increasing trend when extraordinary drought occurs. In the area III, IV and V, the probability of the different precipitation intensities shows an overall decreasing trend. The areas VI and VII are located at the mountains with high altitudes where the variation of different precipitation intensities with the increase in drought level is relatively complex. (3) As the drought times increase, areas I, II and V, which are located on the coastal and in the valley or basin, are vulnerable to extreme precipitation processes; areas III, IV, VI and VII are located in the inland area, where heavier precipitation is not likely to occur. (4) The local rainfall affected by multiple factors is closely related with drought occurrence. The characteristics between the first rainfall intensity after a drought period and different drought magnitudes (or drought occurrence times) are preliminarily examined in this paper, but its formation mechanism still requires further research.


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