Clearing the Air on the Haze – A Hazy New Year?

Haze

“As any geographer would attest to, the haze itself might be dull in sight, but insight into the haze is surely never boring.”

The Straits Times reported on October 19th 2015 that the haze could persist until 20161. A researcher from the Centre for International Forestry Research was quoted as saying that it might very well last until the final month of 2015 or the first month of next year. Unsurprisingly, many Singaporeans might wonder why we are to bear the brunt of the haze for a longer period than our squeaky clean and ‘sterile’ respiratory airways are normally accustomed to. Amongst the reasons for the persistence of the haze are factors of a geographical nature.

The seasonal monsoons experienced in this part of the world that straddles the Equator are the main culprits. In June 2013, the worst haze in Singapore’s meteorological history was recorded. The southwest monsoon was the main cause of the haze as winds blowing from Sumatra to Singapore carried a comparatively higher concentration of particulate matter (PM) particles with them2. In March 2014, the haze was back again – but this time, the northeast monsoon was the primary cause of the public’s ire. Its northeasterly winds were retreating back northwards3, accompanying the gradually moving Inter-Tropical Convergence Zone (ITCZ) with the approach of warmer temperatures in the northern hemisphere. Now, in October 2015, however, one would expect a taming of the haze as the northeast monsoon comes to our rescue – to rid us of the prevailing southwesterly winds that have been carrying too many PM particles4 with frequencies greater than comfort ordinarily affords. However, in any given locality, the replacement of the southwest monsoon by the northeast monsoon during the inter-monsoon period is a gradual process5 that requires patience on the part of the people who would be expected to relish in this seasonal change.

SST

Diagram 1: Sea Surface Temperature anomalies across the tropical Pacific (22nd October 2015) enable us to visualise the temperature disparities across the Pacific Ocean that drive the El Niño Southern Oscillation. Source: National Oceanic and Atmospheric Administration (NOAA), United States.


This time, however, hope for clearer skies might be further afield than initially expected due to the current cycle of the El Niño Southern Oscillation (ENSO) being experienced in our part of the world. The ENSO is brought about by cross-longitudinal changes in oceanic water circulation that results in a change in temperatures across oceans (Diagram 1). In the case of the eastern margins of the Pacific Ocean, warmer sea surface temperatures bring higher rainfall to South American countries such as Chile. The corollary to this is that Singapore and the rest of Southeast Asia that lie along the western margins of the Pacific Ocean experience drier conditions brought about by easterly winds rid of moisture6. The ENSO occurs every few years and lasts for variable periods of time7. Drier conditions that may exacerbate forest fires in Indonesia due to the persistence of the ENSO are the reason cited by geographers and meteorologists as to why the haze might continue up until January 2016. It is worth noting that this is certainly not the first time the ENSO and Indonesian forest fires made for a fearsome combination. In 1997, the ENSO brought about forest fires in Kalimantan, Indonesia that emitted a thick aerosol plume, forcing the shutting down of airports in Indonesia, Malaysia and Singapore.

There might exist a commonly held misconception in the Singaporean psyche – that our country does not experience seasonal changes in weather patterns. We do. There is also perhaps a feeling amongst those who are uninitiated with the geography of weather and climate that compared to life in temperate countries, living in Singapore makes for a boring existence due to the high year-round temperatures and rainfall experienced here where snow can only be artificially manufactured in air-conditioned enclosures and where tomorrow’s weather must surely be as mundane as that of any other day in the year. On the contrary, our susceptibility to seasonal weather patterns has impacts on our daily lives that are more real than one might imagine, given the right conditions (in this case, an anthropogenic condition imposed upon us by our neighbours which is being heightened in its effect by physical conditions). As any geographer would attest to, the haze itself might be dull in sight, but insight into the haze is surely never boring.


References:

[1] The Straits Times. (2015). Hazy new year: South-east Asia set to suffer for months as Indonesia fails to douse fires. (2015, October 19). Retrieved from http://www.straitstimes.com/asia/se-asia/hazy-new-year-south-east-asia-set-to-suffer-for-months-as-indonesia-fails-to-douse.

[2] Velasco, E. & Rastan, S. (2015). Air quality in Singapore during the 2013 smoke-haze episode over the Strait of Malacca: Lessons learned. Sustainable Cities and Society, 17, 122-131.

[3] Meteorological Service Singapore. (2014). Update of Regional Weather and Smoke Haze for April 2014. Singapore: Government of Singapore. Retrieved from http://wip.weather.gov.sg/wip/pp/ssops/reparch/apr14.pdf.

[4] Ministry of Foreign Affairs. (2015). Press Statement: Singapore Registers Haze Concerns with Indonesia. (2015, September 10). Retrieved from http://www.mfa.gov.sg/content/mfa/overseasmission/jakarta/press_statements_speeches/2015/201509/Singapore_Registers_Haze_Concerns_With_Indonesia.html.

[5] ASEAN Specialised Meteorological Centre. (2015). Update of Regional Weather and Smoke Haze for September 2015. Singapore: Association of Southeast Asian Nations. Retrieved from http://asmc.asean.org/wp-content/uploads/2015/09/Sep15.pdf.

[6] Cane, M. (2005). The evolution of El Niño, past and future. Earth and Planetary Science Letters, 230, 227-240.

[7] Chen, D. & Cane, M.A. (2008). El Niño prediction and predictability. Journal of Computation Physics, 227, 3625-3640.

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