A statistical approach towards a regionalization of daily rainfall in Sri Lanka

Domroes, Manfred; Ranatunge, E

doi:10.1002/joc.3370130704

Cited by 23 publications

(13 citation statements)

References 40 publications

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“…The country is divided according to the temporal and spatial variations of rainfall into two distinct zones, the dry zone and the wet zone (Domroes and Ranatunge 1993). In general, the wet zone receives rainfall throughout the year while the dry zone experiences long dry periods.…”

Section: Study Areamentioning

confidence: 99%

Century scale climate change in the central highlands of Sri Lanka

Silva

Sonnadara

2016

J Earth Syst Sci

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In this study, an analysis of century scale climate trends in the central highlands of Sri Lanka is presented. Monthly rainfall and temperature records of the period 1869-2006 from five climatological stations were analyzed. The trend is calculated by the least square regression analysis and the significance of the observed trend is estimated using the Mann-Kendall statistic. The results clearly show that there is a statistically significant decrease in annual rainfall in the western slopes of the central highlands. Throughout the last century, the annual reduction of rainfall in Nuwara Eliya which is at an altitude of 1895 m was 5.2 mm/year. The decrease is largely due to the reduction in southwest monsoon rainfall which contributes to 75% of the total reduction. No significant change was observed on the eastern side of the central highlands which receives rainfall predominantly from the northeast monsoons. The mean annual temperature in the mountainous region shows a uniform increasing trend which is in line with the 100-year global temperature increase of 0.8 ± 0.2 • C. Kandy, which is at an altitude of 477 m and closely linked with the rainfall climatology of Nuwara Eliya, showed no significant change in the mean annual temperature. If the current trend continues, in another 100 years, western and eastern slopes of central highlands will receive the same amount of rainfall from the southwest monsoon and the northeast monsoon which will have far reaching consequences for Sri Lanka's economy and the ecology of the hill country.

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Section: Study Areamentioning

confidence: 99%

Century scale climate change in the central highlands of Sri Lanka

Silva

Sonnadara

2016

J Earth Syst Sci

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“…Furthermore, the northward and southward migrations of the Inter Tropical Convergence Zone (ITCZ) during the year also govern the climate. Four seasons were identified in past studies [1]. These are the Northeast monsoon from December to February, South-West monsoon from May to September, First intermonsoon from March to April and Second intermonsoon from October to November.…”

Section: Datamentioning

confidence: 99%

Trends of Rainfall in Sri Lanka over the Last Century

2005

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Utilizing over 100 years of rainfall records in 15 meteorology stations, an analysis was carried out to extract the trends of annual rainfall depth in Sri Lanka over the last century. A statistically significant increasing trend of rate 3.15 mm/year was observed at Colombo and decreasing trends were observed at Nuwara Eliya and Kandy with rates of 4.87 mm/year and 2.88 mm/year respectively. Since no coherent increase or decrease of rainfall in any group of stations in the wet or dry zones was observed, the possibility of large scale change over the past century was ruled out. However, more recent data records (1949 onwards), revealed a decreasing trends in 13 of the 15 stations. Thus, traces of a temporal change seem to be apparent in the rainfall records over the last half century. In general, the downward trends in recent decades are steeper than the long term variations. For the recent data records, the largest downward trend of 11.16 mm/year was observed at Batticaloa. 9 data records maintained by the Department of Meteorology, Sri Lanka [2]. They have applied the necessary quality control checks on the data and estimated missing values using difference and ratio methods suggested by Thom [3]. The recent data records were obtained from the IRI monthly climatic data (IRI/LDEO Climate data Library) and Statistical abstracts from the Department of Meteorology as well as through direct purchase. Table 1 shows a summary of the selected rainfall stations used in this work.

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“…‫ﻧﺪارد.‬ ‫وﺟﻮد‬ ‫ﺑﺎرﺷﯽ‬ ‫روزﻫﺎی‬ ‫از‬ ‫ﯾﮑﺴﺎﻧﯽ‬ ‫ﺗﻌﺮﯾﻒ‬ ‫ﮔﺎﯾﺠﺎرو‬ ‫و‬ ‫ﺳﺎﻣﺮ‬ [Summer & Guijaro, 1993] ‫ﻣﯽ‬ ‫ﺑﺎراﻧﯽ‬ ‫را‬ ‫روزی‬ ‫ﮐﻪ‬ ‫داﻧﺪ‬ ‫دﺳﺖ‬ ‫ﮐﻢ‬ ۰٫۱ ‫ﻣﯿﻠﯽ‬ ‫ﺑﺎﺷﺪ.‬ ‫داﺷﺘﻪ‬ ‫ﺑﺎرش‬ ‫ﻣﺘﺮ‬ ‫راﻧﺎﺗﻮﻧﮓ‬ ‫و‬ ‫دوﻣﺮوس‬ [Domroes & Ranatung, 1993] ‫ﻣﺨﺘﻠﻒ‬ ‫ﻣﻨﺎﺑﻊ‬ ‫از‬ ‫ﻧﻘﻞ‬ ‫ﺑﻪ‬ ‫روزﻫﺎی‬ ‫ﻣﯽ‬ ‫اﻧﺠﺎم‬ ‫ﻣﺎﯾﻞ‬ ‫و‬ ‫ﻋﻤﻮدی‬ ‫ﺻﻮرت‬ ‫دو‬ ‫ﺑﻪ‬ ً ‫ﻣﻌﻤﻮﻻ‬ ‫ﺷﻮد‬ [Alijani, 2002] ‫درﻧﻬﺎﯾﺖ‬ [Alijani, 2002] . [Mofidi et al, 2007, Janbaz Ghobadi et al, 2011Ghayor et al, 2011]…”

Section: ‫اﯾﻦ‬ ‫از‬unclassified