1 / 39

Holiday effect of the Taipei Metropolitan area 台北都會區的假期效應

Holiday effect of the Taipei Metropolitan area 台北都會區的假期效應. 報告人：談珮華 博士 國立嘉義大學史地學系副教授 日期： 2009 年 10 月 7 日. Goal. Study the holiday effect over the Taipei Metropolitan area. Holiday effect The statistically significant differences of variables between holiday and non-holiday periods.

terrel
Download Presentation

Holiday effect of the Taipei Metropolitan area 台北都會區的假期效應

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Holiday effect of the Taipei Metropolitan area台北都會區的假期效應 報告人：談珮華 博士國立嘉義大學史地學系副教授 日期：2009年10月7日

  2. Goal • Study the holiday effect over the Taipei Metropolitan area. • Holiday effect • The statistically significant differences of variables between holiday and non-holiday periods.

  3. The weekend effect 週末效應 • Stock market • Disease, syndrome

  4. Introduction (1) • Weekend effect of air pollutants • Gaseous pollutants such as NOx, CO, VOCs 揮發性有機物or NMHC非甲烷碳氫化合物, and SO2 higher on weekdays than on weekends (e.g., Bronnimann and Neu 1997; Beirle et al. 2003; Qin et al. 2004; Riga-Karandinos and Saitanis 2005; Steinbacher et al. 2005; Riga-Karandinos et al. 2006) • Particulate pollutants such as PM10, PM2.5, PM1, and black carbon  higher on weekdays than on weekends (Morawska et al. 2002; Madhavi Latha and Badarinath 2003) .

  5. 污染來源 • 氣狀污染物 • 粒狀污染物 • NOx, CO, NMHC, O3, SO2, PM10

  6. Introduction (2) • O3: major secondary air pollutant a more complex distribution • Lower on weekdays than weekends (e.g., Cleveland et al. 1974; Lebron 1975; Bronnimann and Neu 1997; Diem 2000; Qin et al. 2004; Riga-Karandinos and Saitanis 2005; Tsai 2005; Riga-Karandinos et al. 2006) • Higher on weekdays than weekends (Bronnimann and Neu 1997; Diem 2000) • ?? O3 precursor substances, such as NOx and NMHC, are decreased on weekends, while O3 is simultaneously increased.

  7. Introduction (3) • Several hypotheses for O3 weekend effect (California Air Resources Board, 2003). (1) nonlinear relation between O3 and its precursors: lower NOx on weekends a faster ozone production rate in NOx-saturated (VOC-limited) areas (2) NO titration effect (NO滴定效應): lower NOx  less ozone destruction on weekends, ozone↑, O3 + NO NO2+O2 (3) aerosol and UV radiation: on weekends, aerosol ↓ sunshine↑ ozone↑ (4) NOx timing: delayed weekend traffic patterns and stronger sunshine  ozone↑ (5) carry-over emissions: higher traffic volumes on Friday evenings than on weekends more O3 precursors on weekends

  8. Introduction (4) • Weekend effect of meteorological parameters • Diurnal temperature range, DTR (Forster and Solomon 2003; Gong et al. 2006a)日溫差 • dayily minimum temperature, Tmin (Forster and Solomon 2003)最高溫 • dayily maximum temperature, Tmax (Gong et al., 2006a)最低溫 • daily precipitation frequency (Gong et al., 2006b) • annual precipitation and tropical cyclonic mean maximum wind speed (Cerveny and Balling 1998) • seasonal rainfall, seasonal maximum and minimum temperature (Simmonds and Keay 1997) • visibility (Tsai 2005)能見度

  9. avg (Sat-Mon) – avg (Wed-Fri) DTR avg (Sat-Mon) – avg (Wed-Fri) Tmin Forster and Solomon (2003) • Most weekend-weekday differences are statistically significant, but their sign might be opposite for different regions or seasons (Forster and Solomon 2003, Gong et al. 2006a), and are attributed to anthropogenic influences (Cerveny and Balling 1998; Forster and Solomon 2003).

  10. Introduction (5) • Weekend effect: a useful tool to detect the influence of human-related activities on the environment and climate system. • Other similar effects, such as “holiday effect”, provide a possibility to study such phenomena for regions not showing a clear weekend effect.

  11. Part 1. air pollutant concentrations • Part 2. meteorological parameters

  12. Part 1. air pollutant concentrations • The method • the Chinese New Year holiday • the most important holiday for the Chinese people. • The Chinese New Year (CNY) and non-Chinese New Year (NCNY) periods. • 春節及非春節期間

  13. The CNY and NCNY periods Sources: Taiwan Central Personnel Administration (1994-2006)

  14. Part 1. air pollutant concentrations • The method Weather effect a longer record in time  filter out the random change of weather climatic feature

  15. The study area 6.39 million inhabitants Population density 2750 /km2

  16. The data • NOx, CO, NMHC, O3, SO2, PM10 • Hourly and daily surface measurements of six major air pollutants from thirteen (four for NMHC) air quality monitoring stations of the Taiwan Environment Administration during the holiday and non-holiday periods in 1994-2006.

  17. Results13-station daily mean air pollutant concentrations in 1994-2006 < < < > < < *significance with p level < 0.05

  18. CNY NCNY

  19. Total oxidants In CNY, at noon, UVA & UVB , if nonlinear, NOx↓, O3↑, But O3 

  20. Ozone holiday effect O(1) nonlinear relation between O3 and its precursors: lower NOx on weekends a faster ozone production rate in NOx-saturated (VOC-limited) areas OO (2) NO titration effect: lower NOx, lower NO  less ozone destruction on weekends X(3) aerosol and UV radiation: on weekends, aerosol ↓ sunshine↑ ozone↑; in CNY, aerosol ↓ ozone↑ but sunshine  X(4) NOx timing: delayed weekend traffic patterns and stronger sunshine, ozone↑; in CNY, no such pattern X(5) carry-over emissions: higher traffic volumes on Friday evenings than on weekends more O3 precursors on weekends; 4-8 days in CNY

  21. CNY NCNY Concentration (ppb) Concentration (g/m3) NCNY NCNY CNY CNY

  22. The effect of dust • The influence levels of dust storms on Taiwan • Daily maximum PM10 concentrations for any of the three air quality monitoring stations in northern Taiwan • 0  < 150 g/m3 • 1  150-200 g/m3 • 2  200-300 g/m3 • 3  300-400 g/m3 CNY: dust & no-dust cases NCNY: dust & no-dust cases

  23. Conclusions (1) • Holiday effect of air pollutant concentrations was found over the Taipei Metropolitan area. • Daily (24-h)mean, diurnal cycle and interannual variation • NOx, CO, NMHC, SO2 and PM10: CNY< NCNY • O3: CNY > NCNY • The diurnal cycles of the differences of O3, total oxidants and NOx between the CNY and NCNY periods NO titration effect is more important

  24. Conclusions (2) • 1994-2006 • NOx and CO: negative trends in NCNY • SO2 and PM10: positive trends in CNY  Holiday effect is weakening. • The long-range transport of dust SO2 and PM10 in CNY and NCNY stronger impact in CNY due to cleaner air in CNY.

  25. Conclusions (3) • It involved a great movement of people and motor vehicles before and after the CNY period, the observed holiday effect provided evidence of the impact of human activity on ambient air quality. • Holiday effect in other countries with similar national or cultural holidays.

  26. Part 2. meteorological parameters • The goal • the holiday effect • The relation between air pollutants (PM10) and meteorological parameters • Radiation effects of aerosol • 懸浮微粒的輻射效應 • Direct effect 直接輻射效應 • Indirect effect 間接輻射效應 • Semi-direct effect 半直接輻射效應

  27. IPCC AR4 (2007)

  28. Part 2. meteorological parameters • The method • The study area • The data: • 13 EPA stations(1994-2006, 13 years) • 2 CWB stations(1986-2006, 21 years) • surface measurement of Taipei weather station • Radiosonde measurement of Banqiao station (00Z, 12Z) • Tmax, Tmin, Tavg, DTR • cloud cover, sunshine hour, sunshine rate, • global solar radiation, rainfall, visibility • Vertical profile of temperature

  29. Results not statistically significant  Tmin, global solar radiation, rainfall, visibility

  30. CWB radiosonde measurement (00Z) • In average, warmer atmosphere in the NCNY than CNY period. • atmospheric stability dT/dz • 1000-500mb • NCNY: -4.73 ℃/km • CNY : -4.89 ℃/km (CNY more unstable)

  31. Conclusions (1) Holiday effects: DTR, Tmax, Tavg, cloud cover, sunshine hour, sunshine rate

  32. Conclusions (2) • Compared to CNY, in the NCNY • Semi-direct effect • aerosol (PM10)↑, absorbed solar radiation ↑, warmer atmosphere, stability ↑, convection↓, cloud cover↓, sunshine hour ↑, sunshine rate ↑, Tmax ↑, DTR ↑ • aerosol in Taipei, SSA≒0.76-0.79, many light-absorbed aerosols, Shiu (2008) • Direct effect:  aerosol (PM10)↑, absorbed solar radiation↑, surface radiation↓ sunshine hour↓  but sunshine hour ↑ • Indirect effect: • aerosol (PM10)↑, CCN ↑, cloud cover ↑  but cloud cover↓

  33. Conclusions • Semi-direct radiation effect • Sounding data • ……..

  34. CWB radiosonde measurement • In average, warmer atmosphere in the NCNY period. • But, the standard deviation is large if viewed year by year. • Not a strong evidence. • ………..

  35. 參考資料 • Tan, P.-H., C. Chou, J.-Y. Liang, C. C.-K. Chou, C.J. Shiu, 2009: Air pollution “holiday effect” resulting from the Chinese New Year, Atmos. Environ., 43 (13), 2114-2124. • 談珮華、周佳、梁靜宜、吳柏霖，2008：台北都會區的假期效應，大氣科學，36 (3)，197-215。

  36. Thank you for your attention!!

  37. NOx-saturated area BACK

  38. O3 cycle NO + O3 -> NO2 + O2 (1) NO2 + hυ -> NO + O (2) O + O2 + M -> O3 + M (3)

More Related