Geography of Sri Lanka
Nickname: Pearl of the Indian Ocean | |
---|---|
Sri Lanka Tamils – 16%, Sri Lankan Moors – 9% |
Sri Lanka's climate includes tropical
Geology
More than 90% of Sri Lanka's surface lies on
The island contains relatively limited strata of sedimentation surrounding its ancient uplands.
Topography
Extensive faulting and erosion over time have produced a wide range of topographic features.[6] Three zones are distinguishable by elevation: the Central Highlands, the plains, and the coastal belt.[6]
The south-central part of Sri Lanka—the rugged
Most of the island's surface consists of plains between 30 and 200 meters above sea level.[6] In the southwest, ridges and valleys rise gradually to merge with the Central Highlands, giving a dissected appearance to the plain.[6] Extensive erosion in this area has worn down the ridges and deposited rich soil for agriculture downstream.[6] In the southeast, a red, lateritic soil covers relatively level ground that is studded with bare, monolithic hills.[6] The transition from the plain to the Central Highlands is abrupt in the southeast, and the mountains appear to rise up like a wall.[6] In the east and the north, the plain is flat, dissected by long, narrow ridges of granite running from the Central Highlands.[6]
A coastal belt about thirty meters above sea level surrounds the island.[6] Much of the coast consists of scenic sandy beaches indented by coastal lagoons.[6] In the Jaffna Peninsula, limestone beds are exposed to the waves as low-lying cliffs in a few places.[6] In the northeast and the southwest, where the coast cuts across the stratification of the crystalline rocks, rocky cliffs, bays, and offshore islands can be found; these conditions have created one of the world's best natural harbors at Trincomalee on the northeast coast, and a smaller rock harbor at Galle on the southwestern coast.[6]
Climate
Sri Lanka's climate can be described as
The rainfall pattern is influenced by the monsoon winds of the Indian Ocean and Bay of Bengal and is marked by four seasons.[6] The first is from mid-May to October, when winds originate in the southwest, bringing moisture from the Indian Ocean.[6] When these winds encounter the slopes of the Central Highlands, they unload heavy rains on the mountain slopes and the southwestern sector of the island.[6] Some of the windward slopes receive up to 2,500 mm (98.4 in) of rain per month, but the leeward slopes in the east and northeast receive little rain.[6] The second season occurs in October and November, the intermonsoonal months.[6] During this season, periodic squalls occur and sometimes tropical cyclones bring overcast skies and rains to the southwest, northeast, and eastern parts of the island.[6] During the third season, December to March, monsoon winds come from the northeast, bringing moisture from the Bay of Bengal.[6] The northeastern slopes of the mountains may be inundated with up to 1,250 mm (49.2 in) of rain during these months.[6] Another intermonsoonal period occurs from March until mid-May, with light, variable winds and evening thundershowers.[6]
An increase in average rainfall coupled with heavier rainfall events has resulted in recurrent flooding and related damages to infrastructure, utility supply and the urban economy.[8]
Humidity is typically higher in the southwest and mountainous areas and depends on the seasonal patterns of rainfall.[6] At Colombo, for example, daytime humidity stays above 70% all year, rising to over 90% percent during the monsoon season in June.[6] Anuradhapura experiences a daytime low of 60% during the intermonsoonal month of March, but a high of 79% during the November and December rains.[6] In the highlands, Kandy's daytime humidity usually ranges between 70 and 79%.[6]
Climate data for Colombo, Sri Lanka (1961–1990, extremes 1961–2012) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
Record high °C (°F) | 35.2 (95.4) |
35.6 (96.1) |
36.1 (97.0) |
35.2 (95.4) |
33.2 (91.8) |
33.5 (92.3) |
32.2 (90.0) |
32.2 (90.0) |
32.5 (90.5) |
33.6 (92.5) |
34.0 (93.2) |
35.0 (95.0) |
36.1 (97.0) |
Mean daily maximum °C (°F) | 31.0 (87.8) |
31.2 (88.2) |
31.7 (89.1) |
31.8 (89.2) |
31.1 (88.0) |
30.4 (86.7) |
30.0 (86.0) |
30.0 (86.0) |
30.2 (86.4) |
30.0 (86.0) |
30.2 (86.4) |
30.4 (86.7) |
30.7 (87.3) |
Daily mean °C (°F) | 26.6 (79.9) |
26.9 (80.4) |
27.7 (81.9) |
28.2 (82.8) |
28.3 (82.9) |
27.9 (82.2) |
27.6 (81.7) |
27.6 (81.7) |
27.5 (81.5) |
27.0 (80.6) |
26.7 (80.1) |
26.6 (79.9) |
27.4 (81.3) |
Mean daily minimum °C (°F) | 22.3 (72.1) |
22.7 (72.9) |
23.7 (74.7) |
24.6 (76.3) |
25.5 (77.9) |
25.5 (77.9) |
25.1 (77.2) |
25.1 (77.2) |
24.8 (76.6) |
24.0 (75.2) |
23.2 (73.8) |
22.8 (73.0) |
24.1 (75.4) |
Record low °C (°F) | 16.4 (61.5) |
18.8 (65.8) |
17.7 (63.9) |
21.2 (70.2) |
20.5 (68.9) |
21.4 (70.5) |
21.4 (70.5) |
21.6 (70.9) |
21.2 (70.2) |
21.0 (69.8) |
18.6 (65.5) |
18.1 (64.6) |
16.4 (61.5) |
Average precipitation mm (inches) | 58.2 (2.29) |
72.7 (2.86) |
128.0 (5.04) |
245.6 (9.67) |
392.4 (15.45) |
184.9 (7.28) |
121.9 (4.80) |
119.5 (4.70) |
245.4 (9.66) |
365.4 (14.39) |
414.4 (16.31) |
175.3 (6.90) |
2,523.7 (99.35) |
Average precipitation days | 5 | 5 | 9 | 14 | 16 | 16 | 12 | 11 | 15 | 17 | 15 | 10 | 145 |
Average relative humidity (%) (at Daytime)
|
69 | 69 | 71 | 75 | 78 | 79 | 78 | 77 | 78 | 78 | 76 | 73 | 75 |
Mean monthly sunshine hours | 248.0 | 246.4 | 275.9 | 234.0 | 201.5 | 195.0 | 201.5 | 201.5 | 189.0 | 201.5 | 210.0 | 217.0 | 2,621.3 |
Source 1: NOAA[9] World Meteorological Organization (precipitation only)[10] | |||||||||||||
Source 2: Deutscher Wetterdienst (extremes)[11] |
Climate data for Kandy | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
Mean daily maximum °C (°F) | 27 (81) |
28 (82) |
30 (86) |
30 (86) |
29 (84) |
28 (82) |
27 (81) |
28 (82) |
28 (82) |
28 (82) |
27 (81) |
27 (81) |
28 (83) |
Daily mean °C (°F) | 23.1 (73.6) |
24.1 (75.4) |
25.4 (77.7) |
25.9 (78.6) |
25.6 (78.1) |
24.8 (76.6) |
24.3 (75.7) |
24.4 (75.9) |
24.3 (75.7) |
24.3 (75.7) |
24 (75) |
23.7 (74.7) |
24.5 (76.1) |
Mean daily minimum °C (°F) | 18 (64) |
18 (64) |
18 (64) |
20 (68) |
20 (68) |
20 (68) |
20 (68) |
19 (66) |
19 (66) |
19 (66) |
19 (66) |
18 (64) |
19 (66) |
Average precipitation mm (inches) | 79 (3.1) |
74 (2.9) |
71 (2.8) |
188 (7.4) |
144 (5.7) |
132 (5.2) |
128 (5.0) |
113 (4.4) |
155 (6.1) |
264 (10.4) |
296 (11.7) |
196 (7.7) |
1,840 (72.4) |
Average rainy days | 6 | 5 | 8 | 14 | 11 | 15 | 14 | 13 | 13 | 17 | 16 | 14 | 146 |
Mean daily sunshine hours | 7 | 8 | 8 | 7 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 7 |
Source 1: Weather2Travel for highs, lows and sunshine,[12] Climate-Data.org for daily mean temperatures (altitude: 518 m)[13] | |||||||||||||
Source 2: World Climate Guide,[14] HolidayCheck.com,[15] World Climate[16] |
Ecological zones
The pattern of life in Sri Lanka depends directly on the availability of rainwater.[6] The mountains and the southwestern part of the country, known as the "wet zone," receive ample rainfall (an annual average of 2500 millimeters).[6] Most of the southeast, east, and northern parts of the country comprise the "dry zone, which receives between 1200 and 1900 mm of rain annually.[6] Much of the rain in these areas falls from October to January; during the rest of the year there is very little precipitation, and all living creatures must conserve precious moisture.[6] The arid northwest and southeast coasts receive the least amount of rain—600 to 1200 mm per year—concentrated within the short period of the winter monsoon.[6]
The natural vegetation of the dry zone has adapted to the annual change from flood to drought.[6] The typical ground cover is scrub forest, interspersed with tough bushes and cactuses in the driest areas.[6] Plants grow very fast from November to February when rainfall is heavy, but stop growing during the hot season from March to August.[6] Various adaptations to the dry conditions have developed.[6] To conserve water, trees have thick bark; most have tiny leaves, and some drop their leaves during this season.[6] Also, the topmost branches of the tallest trees often interlace, forming a canopy against the hot sun and a barrier to the dry wind.[6] When water is absent, the plains of the dry zone are dominated by browns and grays.[6] When water becomes available, either during the wet season or through proximity to rivers and lakes, the vegetation explodes into shades of green with a wide variety of beautiful flowers.[6] Varieties of flowering acacias are well adapted to the arid conditions and flourish on the Jaffna Peninsula.[6] Among the trees of the dry-land forests are some valuable species, such as satinwood, ebony, ironwood, and mahogany.[6]
In the wet zone, the dominant vegetation of the lowlands is a tropical evergreen forest, with tall trees, broad foliage, and a dense undergrowth of vines and creepers.[6] Subtropical evergreen forests resembling those of temperate climates flourish in the higher altitudes.[6] Montane vegetation at the highest altitudes tends to be stunted and windswept.[6]
Forests at one time covered nearly the entire island, but by the late 20th century lands classified as forests and forest reserves covered only one-fifth of the land.
Land use and settlement patterns
The dominant pattern of human settlement during the last 2,500 years has consisted of village farming communities.[6] Even in the 1980s, the majority of people lived in small villages and worked at agricultural pursuits.[6] Traditional farming techniques and life-styles revolve around two types of farming--"wet" and "dry"—depending upon the availability of water.[6]
The typical settlement pattern in the rice-growing areas is a compact group of houses or neighborhood surrounding one or several religious centers that serve as the focus for communal activities.[6] Sometimes the houses may be situated along a major road and include a few shops, or the village may include several outlying hamlets.[6] The life-sustaining rice fields begin where the houses end and stretch into the distance.[6] Some irrigated fields may include other cash crops, such as sugarcane, or groves of coconut trees.[6] Palmyra trees grow on the borders of fields or along roads and paths.[6] Individual houses also may have vegetable gardens in their compounds.[6] During the rainy seasons and thereafter, when the fields are covered by growing crops, the village environment is intensely verdant.[6]
The nature of agricultural pursuits in Sri Lanka has changed over the centuries and has usually depended upon the availability of arable land and water resources.
Beginning in the 16th century and culminating during the
The coastal belt surrounding the island contains a different settlement pattern that has evolved from older fishing villages.[6] Separate fishing settlements expanded laterally along the coast, linked by a coastal highway and a railway. The mobility of the coastal population during colonial times and after independence led to an increase in the size and number of villages, as well as to the development of growing urban centers with outside contacts.[6] In the 1980s, it was possible to drive for many kilometers along the southwest coast without finding a break in the string of villages and bazaar centers merging into each other and into towns.[6]
Statistics
Land use (2018): 20.7% arable land, 15.8% permanent crops, 7% permanent pasture, 29.4% forest, 27.1% other.[1]
Irrigated land: 5,700 km2 (2012)[1]
Total renewable water resources: 52.8 cubic km[1]
Natural hazards: occasional cyclones and tornadoes[1]
Environmental issues: deforestation; soil erosion; wildlife populations threatened by poaching and urbanization; coastal degradation from mining activities and increased pollution; freshwater resources being polluted by industrial wastes and sewage runoff; waste disposal; air pollution in Colombo[1]
Maritime claims
- contiguous zone: 24 nmi (44.4 km; 27.6 mi)[1]
- continental shelf: 200 nmi (370.4 km; 230.2 mi) or to the edge of the continental margin[1]
- exclusive economic zone: 200 nmi (370.4 km; 230.2 mi)[1]
- territorial sea: 12 nmi (22.2 km; 13.8 mi)[1]
See also
References
- ^ a b c d e f g h i j k l m n o "Sri Lanka". The World Factbook. Central Intelligence Agency. May 11, 2021. Retrieved May 14, 2021. This article incorporates text from this source, which is in the public domain.
{{cite web}}
: CS1 maint: postscript (link) - ^ "Joshua Calder's World Island Info – Largest Islands of the World". Worldislandinfo.com. Retrieved 2016-01-30.[unreliable source?]
{{cite web}}
: CS1 maint: postscript (link) - ^ www.jpp.co.jp https://www.jpp.co.jp/lanka/geo/geote/geo05e.htm. Retrieved 2023-04-14.
{{cite web}}
: Missing or empty|title=
(help) - ^ Manimaran, G. (2008-08-01). "Geoenvironmental Scenario on the Landward Migration of Thamiraparani Microlithic Culture to Sri Lanka Through Adam's Bridge". Journal of the Geological Society of India. 72: 222–224..
- ^ "Adam's bridge". Encyclopædia Britannica. 2007. Archived from the original on 13 January 2008. Retrieved 14 September 2007.
- ^ OCLC 311429237. This article incorporates text from this source, which is in the public domain.)
{{cite encyclopedia}}
: CS1 maint: postscript (link - ^ Pathirana, H.D.N.C., 1980, Geology of Sri Lanka in relation to Plate Tectonics; L. Natn. Sci. Coun. Sri Lanka v. 8, p. 75-85
- ^ Integrating urban agriculture and forestry into climate change action plans: Lessons from Sri Lanka, Marielle Dubbeling, the RUAF Foundation, 2014
- ^ "Colombo Climate Normals 1961–1990". National Oceanic and Atmospheric Administration. Retrieved November 19, 2016.
- ^ "World Weather Information Service – Colombo". World Meteorological Organization. Archived from the original on February 18, 2017. Retrieved November 19, 2016.
- ^ "Klimatafel von Colombo (Kolamba) / Sri Lanka (Ceylon)" (PDF). Baseline climate means (1961–1990) from stations all over the world (in German). Deutscher Wetterdienst. Archived from the original (PDF) on 16 April 2019. Retrieved November 19, 2016.
- ^ "Best Weather in Kandy, Sri Lanka". Weather2Travel. Retrieved 12 November 2013.
- ^ "Climate: Kandy CP (altitude: 518 m) – Climate graph, Temperature graph, Climate table". Climate-Data.org. Retrieved 12 December 2013.
- ^ www.worldclimateguide.co.uk. "Kandy Climate Guide, Sri Lanka – World Climate Guide".
- ^ Temperature Kandy – climate Kandy Sri Lanka (Inside) – weather Kandy Archived 25 January 2013 at archive.today
- ^ "World Climate: N07E080 – Weather history for travel real estate and education".
- ^ Darashaw Nosherwan Wadia (1943). "Records of the Department of Mineralogy, Ceylon".
{{cite journal}}
: Cite journal requires|journal=
(help)