Hot and Humid Climate of Singapore

Background of National Library

The National Library is Singapore’s knowledge institution that stores all the books with relevant knowledge about almost everything. With massive cultural and literary heritage, it provides trusted references for patrons.

The National Library of Singapore (NLS), situated in the National Library Building on 100 Victoria Street, empowers individuals and businesses with knowledge and information as it continues to expand its vast lineup of reference collections and services. The NLS is responsible for preserving the nation’s literary, heritage, intellectual memory and also making them easily accessible. Beginnings of the National LibraryThe National Library started in 1823 and was inevitably bounded to the establishment of Singapore’s first major educational institution, The Singapore Institution, now renamed as Raffles Institution after the founder of modern Singapore, Sir Stamford Raffles. Stamford Raffles worked for the British East India Company, a purely commercial enterprise but he was a self-made man who fervently believed in the opportunities afforded by education and its ability to benefit the poor. Soon after the founding of Singapore, Raffles proposed setting up an educational establishment and envisioned that a library was needed to support the educational aims of the college.
As such, the seeds of the National Library were sown. Early 1823-1845 The Singapore Library was part of Singapore Institution and the building was completed in 1837. It was only open to students and staffs, however, the public could use it at a price of 25 cents per month. Due to the increasing calls from the public for it to be opened beyond school hours, The Singapore Library was formed and opened on 22 January 1845. Hence The Singapore Library became Singapore’s first subscription library. The New BuildingOn 12 October 1887, the Governor of Singapore, Sir Frederick Weld, officially opened the new building of the Raffles Library and Museum. Japanese OccupationFor 2 weeks before Singapore fell to the Japanese on 15 February 1942, the British and Australian forces occupied the library as a Regimental Aid Station. Thereafter, it was closed only to be reopened officially on 29 April 1942, on the occasion of the birthday of the Japanese Emperor.

The Raffles Library and Museum were renamed the Syonan Hakubutsu Kan, as the museum, as compared to the library, was more eminent during the pre-war period. The library section was known as the Syonan Tosyokan and was headed by Marquis Yoshichika Tokugawa who was related to the Emperor of Japan, a situation that was propitious to the safeguarding of the library and its collections. Post-war YearsThe library was reopened to the public under British Administration on 1 December 1945. The perseverance, steadfastness and relative safety of the library during the Japanese Occupation cemented the role and importance of the library, as an emblem of Singapore’s cultural heritage and ‘an epitome of commitment by all to consolidate society through shared knowledge and experience’.The National Library @ Stamford RoadLee Kong Chian laid the foundation stone of the National Library at Stamford Road on 15 August 1957. The National Library building, which was supposed to reflect the red-brick epoch of British architecture in the 1950s, received mixed reviews. Most criticised the aesthetics of the building which stood in contrast to the dignified and Victorian style architecture of the National Museum. The library building, however, was four times larger than its old size and brought about much-needed space.

A Chapter Ends

The iconic red-bricked National Library at Stamford Road closed its doors for the last time on 31 March 2004, six years after the government announced that the building would be demolished for urban redevelopment. Given the special place the National Library had in the hearts and minds of many Singaporeans, a year-long series of events were planned to commemorate the closing of one chapter and to beginning of a new one half a century later, Lee Kong Chian’s legacy and support continued with a $60 million donation from the Lee Foundation towards the development of the new National Library at Victoria Street. The reference library is named in honor of Lee Kong Chian. National Library Site Plan & Orientation Figure 1: Satellite image of National Library Site PlanAs you can see from the satellite view of the site above, the building entrance is facing the North-East direction. The sun rises in the east and sets in the west hence the building’s entrance will not be exposed to full impact sunlight throughout the day. National Library Floor Plan Figure 2: National Library Floor Plan (B3-L9)Figure 3: National Library Floor Plan (L10-Roof) The 2 photos above shows the floor plans of The National Library from Basement 3 to the Roof.

As you can see from the photos above, the building is something like a modified square shaped building from the top view and almost the entire exterior facades are made up of glass. This allows maximum natural lighting during the daytime and also at night and as a result of this, artificial lightings costs can be reduced. This is considered a passive design which will be touched on more in the passive design section below. Characteristics of Hot & Humid ClimatesClimates around the world are classified according to the Köppen Climate Classification System. The classifications in this system are based on temperature and precipitation averages on a monthly and yearly basis. Humid tropical climates have distinguishing characteristics other than temperature and precipitation.

Tropical humid climates have distinct locations and abundant animal and plant life.TemperatureRainforests are warm with temperatures staying around 80 degrees Fahrenheit year-round and fluctuating little during any given month or year. More fluctuation occurs in daily temperature than in monthly or yearly temperature. Areas with a humid tropical never experience frost.LocationLatitude is a determining factor in the existence of tropical climates. All humid tropical climates are near the equator between the Tropic of Cancer and the Tropic of Capricorn or latitudes that range between 10 degrees south to 25 degrees north. Climate Conditions of The National LibraryThe National Library is located in Singapore and the building experiences a hot & humid climate. The characteristics of a hot & humid climate are as follows: General Climate ConditionsSingapore is situated near the equator and experiences typically tropical climate with abundant rainfall, high and uniform temperatures, high humidity all year round and many of its climate variables, such as temperature and relative humidity, do not show large month-to-month variation. In addition, many other variables exhibit prominent diurnal or daily variations from hour to hour, indicating the strong influence that solar heating has on the local climate.

Seasons in SG

In Singapore, there are two monsoon seasons separated by inter-monsoonal periods. The Northeast Monsoon occurs from December to early March and the Southwest Monsoon from June to September. The major weather systems affecting Singapore that can lead to heavy rainfall are:Monsoon surges, or strong wind episodes in the Northeast Monsoon flow bringing about major rainfall events;Sumatra squalls, an organised line of thunderstorms travelling eastward across Singapore, having developed over the island of Sumatra or Straits of Malacca west of us;Afternoon and evening thunderstorms caused by strong surface heating and by the sea breeze circulation that develops in the afternoon. The occurrence of these events at different times of year is outlined in the following table. Figure 4: Table showing different weather systems throughout the year and the weather characteristics Rainfall

Rainfall is plentiful in Singapore and it rains an average of 167 days* of the year. Much of the rain is heavy and accompanied by thunder. [*A day is considered to have “rained” if the total rainfall for that day is 0.2mm or more.] Figure 5: Number of Raindays throughout the year Figure 6: Amount of rainfall throughout the year Figure 7: The amount of rain in a day and its trend throughout the year While there is no distinct wet or dry season in Singapore, monthly variations in rainfall do exists. Higher rainfall occurs from November to January during the wet phase of Northeast Monsoon season (Figures 5 – 7), when the major tropical rain belt (the Intertropical Convergence Zone, ITCZ) is positioned near to us. The driest month is February which is during the dry phase of the Northeast Monsoon when the rain-belt has moved further south to affect Java. Rainfall in Singapore occurs more frequently during the daytime, particularly in the afternoons when solar heating is strongest. In terms of rainfall distribution across Singapore, rainfall is higher over the northern and western parts and decreases towards the eastern part of the island.TemperatureFigure 8: Categorisation of max and min temperatures in SG throughout the year figure 9: Temperature ranges throughout the day throughout the year Compared to countries in the temperate regions, temperatures in Singapore very little from month to month and also from day to day.

The daily temperature range has a minimum of about 23-25ºC during the night and maximum of about 31-33ºC during the day.

May and June have the highest average monthly temperature (24-hour mean of 27.8ºC) and December and January are the coolest (24-hour mean of 26.0ºC). Singapore, being an island also has a coastal climate and the sea has a moderating influence on Singapore’s climate. This is because water has a larger heat capacity than the land surface, and a greater amount of heat is required to increase the sea temperatures. During afternoons, conditions at the coast are often relieved by sea breezes. The presence of significant wind speeds, rainfall and cloud cover are the most important natural influences in mitigating the tropical heat.HumidityRelative humidity shows a fairly uniform pattern throughout the year and does not vary much from month to month (Fig 10). Its daily variation is slightly more notable, with the values varying from more than 90% in the morning just before sunrise and falling to around 60% in the mid-afternoon on days when there is no rain. The average annual relative humidity is 83.9%. Periodically, the relative humidity frequently reaches 100% and it is due to prolonged durations of rain. Figure 10: Hourly variation of relative humidity for each month (1981-2010) Surface Wind Figure 11: Annual wind rose (m/s) (1981-2010) The most prominent winds in Singapore are from the northeast and the south, reflecting the dominance of the monsoons in Singapore (refer to Fig 11).

On any given day, winds generally follow the prevailing monsoon flow except when light winds are being adjusted by terrain or weather systems. Wind directions blow from northerly to northeasterly during the Northeast Monsoon (December to March) and southerly to southeasterly during the Southwest Monsoon (June to September). Wind strength is greater during the Northeast Monsoon. The inter-monsoon months (April, May, October, and November) are transition periods between the monsoons and show lighter and more variable winds. Figure 12: Hourly variation of surface wind speed (m/s) and direction for each month (1981-2010 average) Figure 13: Average monthly surface wind speed (m/s) Winds throughout the year show a diurnal variation, with lighter winds during the night and stronger winds during the day. The strongest winds occur during the Northeast Monsoon in January and February (Fig 13).

Winds in Singapore are generally light, with the mean surface wind speed normally less than 2.5 m/s except during the presence of a Northeast Monsoon surge when mean speeds of 10m/s or more have been observed. The other times when strong winds occur are during thunderstorms. Surface wind gusts are produced from thunderstorm downdrafts and from the passage of Sumatra squall lines.VisibilityVisibility is generally good during the Northeast Monsoon months from December to March except during rainfall or showers. Slight to moderate haze, which is common during the Southwest Monsoon and in light wind conditions during the inter-monsoon months, can reduce the visibility to below 10 kilometers. During severe episodes of transboundary smoke haze, visibilities below 1 km have been recorded. Poor visibility is also often observed between 0500hr and 0900hr in light to calm wind conditions when mist forms. Visibility, however, usually improves quickly within a few hours after sunrise when the mist dissipates. Following a few hours of rain, poor visibility is also sometimes observed, particularly in almost calm wind conditions. Sunshine DurationSunshine duration refers to the total time during which a specific area receives direct sunlight of at least 120 Watts/m2.

Since Singapore is near the equator, the length of its day is relatively constant throughout the year, and so will the amount of sunshine it receives. Daily sunshine hours are mainly influenced by the presence or absence of cloud cover. They average from four to five hours during the wet periods of eight to nine hours during the dry periods. February and March have the largest number of sunshine hours, while November and December have the lowest (Figs 14 – 15).Figure 14: Average monthly sunshine hours Figure 15: Hourly variation of sunshine hours for each monthCloud CoverCumulus, stratocumulus and cumulonimbus clouds are the most common low cloud types in Singapore. On an average day, cumulus clouds start to develop in the mid-morning, covering to about ? to ½ of the skies by midday with bases of around 0.6 km and tops from 2.5 to 3.5km. During the afternoon and early evening, these cumulus clouds may develop into cumulonimbus clouds with tops reaching between 9 to 12km. The clouds diminish and begin to flatten into stratiform layers by dusk and slowly disperse during the night. Weather systems act to intensify or reduce this diurnal cycle of cloud development.

Overcast conditions caused by extensive middle to high layer clouds together with active cumulus and cumulonimbus clouds are often experienced during the passage of a “Sumatra” squall line. During a Northeast Monsoon surge, broken to overcast medium layer clouds occur together with large cumulus clouds producing prolonged widespread rain and intermittent bouts of heavy rain. Low stratus clouds with bases below 0.3 km are frequently observed following the passage of Sumatra squall lines and during Northeast Monsoon surges.