Interannual variability of precipitation in Sri Lanka

Jayawardene, Hkwi; Jayewardene,; Sonnadara, D. U. J.

doi:10.4038/jnsfsr.v43i1.7917

Cited by 17 publications

(18 citation statements)

References 18 publications

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“…According to Jayawardene et al [51], average rainfall in Colombo, Sri Lanka, will have a significant annual increase of 3.15 mm/year, whereas two other cities Kandy and Nuwara Eliya (about 100-200 km away Colombo) will have an annual decrease of 2.88 and 4.87 mm/year, respectively. Several other researchers including Ampitiyawatta and Guo [52], Herath and Ratnayake [53], Jayawardene et al [54], Malmgren et al [55], Ranatunge et al [56], Suppiah [57], and Wickramagamage [58] have carried out extensive research work to analyse the rainfall trends in many other important areas in Sri Lanka. However, the literature does not show any rainfall trend analysis for the Uma Oya catchment, one of the most important catchments in Sri Lanka.…”

Section: Introductionmentioning

confidence: 99%

Rainfall Trend Analysis in Uma Oya Basin, Sri Lanka, and Future Water Scarcity Problems in Perspective of Climate Variability

Khaniya

Jayanayaka

Jayasanka

et al. 2019

Advances in Meteorology

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The effect of climate variability on the rainfall pattern is canvassed on the Uma Oya river basin, Sri Lanka, consisting of 5 rainfall gauging stations. The Uma Oya basin (720 km2) is given utmost precedence due to environmental concerns seen in the ongoing Uma Oya multipurpose development project (529 million USD worth) which is expected to divert water to the southeast dry zone of the country while adding 231 GWh/year electricity to the national grid. The rainfall data for a period of 26 years (1992–2017) were analysed using Mann–Kendall’s test and Sen’s slope estimator test to identify the rainfall trends. Both of these trend analysis test results depict only one negative trend for Hilpankandura Estate for the month of June; however, the seasonal trend analysis and annual trend analysis do not support this observation. Nevertheless, Mann–Kendall’s test showed potential positive trends for the 3 rainfall gauging stations Kirklees Estate, Ledgerwatte Estate, and Welimada Group only in the 1st intermediate period (March-April), and this is well supported by the monthly trend analysis. Other than these trends, the results do not show any significant negative trends in the Uma Oya catchment. Therefore, the results vividly explain that there is no threat of water scarcity to the catchment area being resistant to changing global climate for the past 26 years.

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Section: Introductionmentioning

confidence: 99%

Rainfall Trend Analysis in Uma Oya Basin, Sri Lanka, and Future Water Scarcity Problems in Perspective of Climate Variability

Khaniya

Jayanayaka

Jayasanka

et al. 2019

Advances in Meteorology

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“…Jayawardene et al [5] have reported that El-Niño Southern Oscillation (ENSO) has consistently lasted for 3-4 years and that Hambantota has shown a periodicity (peak events) of 3.8 years.…”

Section: Figure1 -Main Agro-climatic Zones Of Sri Lanka [25]mentioning

confidence: 99%

Suitability of Silt Deposits of Irrigation Tanks in Angunakolapelessa, Sri Lanka for Engineering Applications

Nawagamuwa

Senarathna²

2018

Engineer

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Dry zone of Sri Lanka is the main contributor to the rice supply in the island nation. Since this zone is prone to long droughts, a large network of agricultural tanks had been built over 1500 years ago to overcome the adverse impacts of the droughts experienced in the zone. Due to poor maintenance and negligence, there is siltation in some of these tanks and as a result of this the water storage of the tanks is not at the optimum level. This study was focused mainly on ten such tanks situated in the Angunakolapelessa Divisional Secretariat Division in the Hambantota District. These tanks require dredging to be at their optimum capacities. It has therefore become necessary to investigate the possible uses of dredged material , i.e., for erosion mitigation, since ad-hoc dumping of erodible dredged materials would in turn adversely affect the capacities of the other tanks located downstream of the cascade. Thirty soil samples were collected from a depth of 300 mm and laboratory tests were conducted on them to study their soil properties. Particle size distribution and Atterberg Test results show that the samples contain mostly clay-silt sediments and according to USCS and USDA classifications, most of them can be classified as silty loam. Standard Proctor Compaction Tests conducted on the samples indicate that the soils have a low maximum dry density and a high optimum moisture content which indicate that the soils tested cannot be recommended for use in embankment/road construction. However, these soils could be reused in erosion barriers/berms erected in agricultural fields. Proper management of irrigation tanks avoiding siltation caused by erosion is recommended to ensure food security and sustainable water management.

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“…Indian Ocean sea surface temperature is the important factor influencing the circulation or rainfall over Indian Ocean rim countries. Indian Ocean Dipole (IOD) plays an important role as a modulator of rainfall in Sri Lanka [38]. Furthermore, the influence of IOD and ENSO are statistically inter-linked and the IOD influence will be highly significant even when there is no ENSO influence and when the two are in competition, the IOD influence will prevail dominantly over that of ENSO [39].…”

Section: Enso Impact On the Seasonal Rainfallmentioning

confidence: 99%

Teleconnection between Cold ENSO Phases and Seasonal Rainfall Over Sri Lanka: Case Study in Kotmale Catchment

Chandrasekara¹,

Chandrasekara

Venkatraman

et al. 2018

Engineer

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Cold ENSO phase or La-Nina is the least considered atmospheric oscillation in the hydro-meteorological sector in Sri Lanka. Therefore, this study focused on understanding teleconnection between cold ENSO phases and the seasonal rainfall over Kotmale catchment. Daily rainfall data of 9meteorological stations were used to investigate behaviour of annual rainfall climatologies of the catchment. Daily mean inflow data of Kotmale reservoir for the duration of 1984-2012 was analysed to understand the trends of the reservoir inflow. Sea surface temperature values were extracted from the Japan Meteorological Agency to determine cold ENSO phase. Rainfall trend for each station and inflow trend of the reservoir both declined throughout the selected time duration. However the rate of decreasing trend changes with each station. Seasonal rainfall of all the stations showed negative correlation with mean sea surface temperature over Nino 3 region for December to September. Cold ENSO phases encounter prominent above-average seasonal rainfall during and the onset of SouthWest monsoon. Further, onset and during of NorthEast monsoon rainfall over the catchment was weakened due to the impact of cold ENSO phase over Nino 3 region. However, further studies are suggested to identify hidden opposite phenomenon observed during cold ENSO phases on 1964 and 1967 in Kotmale catchment, where all the stations experienced worst below-average seasonal rainfall.

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Interannual variability of precipitation in Sri Lanka

Cited by 17 publications

References 18 publications

Rainfall Trend Analysis in Uma Oya Basin, Sri Lanka, and Future Water Scarcity Problems in Perspective of Climate Variability

Rainfall Trend Analysis in Uma Oya Basin, Sri Lanka, and Future Water Scarcity Problems in Perspective of Climate Variability

Suitability of Silt Deposits of Irrigation Tanks in Angunakolapelessa, Sri Lanka for Engineering Applications

Teleconnection between Cold ENSO Phases and Seasonal Rainfall Over Sri Lanka: Case Study in Kotmale Catchment

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