台北都會區的假期效應

Holiday Effect of the Taipei Metropolitan Area

談珮華(Pei-Hua Tan) ； 周佳(Chia Chou) ； 梁靜宜(Jing-Yi Liang) ； 吳柏霖(Bo-Lin Wu)

《大氣科學》 36卷3期 (2008/09) Pp. 197-215

摘要

本研究分析1994~2006年環保署台北縣市13個地面測站，1986~2006年氣象局台北地面測站及板橋探空站的氣象參數，來探討台北都會區春節的假期效應，該定義爲假日與非假日的數值差異是否有統計上的顯著性。結果發現在溫度變數方面，環保署13個測站平均資料在日夜溫差、日最高溫和日均溫皆爲非春節期間大於春節期間，二個期間的差異值分別爲0.61℃、0.53℃及0.22℃，而且具有統計的顯著性。日最低溫在春節期間和非春節期間的差異則未觀察到有統計的顯著性。由氣象局台北地面測站來看，溫度參數在這二個期間雖未有統計上的顯著差異，但其變化趨勢與環保署資料是一致的，而且在差異值的大小也是相當。
在其他氣象參數方面，氣象局台北地面測站資料顯示平均雲量、累積日照時數和日照率，在春節期間和非春節間皆有統計上的顯著差異。平均雲量是春節期間大於非春節期間，累積日照時數及日照率是春節期間小於非春節期間。全天空日射量、累積降雨量及平均能見度則都未發現到統計上顯著的假期效應。
分析懸浮微粒(PM10)與氣象參數之間的關係發現，半直接輻射效應可能與台北都會區的假期效應有關。氣象局板橋探空測站的平均溫度剖面提供了可能但較薄弱的佐證。整體而言，與非春節期間相比，在春節期間空氣中懸浮微粒(PM10)的濃度因汽車活動較少而減少，會吸收較少的太陽輻射，使周圍環境大氣溫度變冷，垂直穩定度變小，進而強化對流使雲量變多，因此累積日照時數及日照率變少，最高溫變低，日夜溫差變小。

關鍵字

假期效應 ； 週末效應 ； 氣候變異 ； 懸浮微粒 ； 半直接輻射效應

並列摘要

This study is aimed to investigate the holiday effect, defined as the difference in meteorological parameters between holiday and non-holiday periods, over the Taipei Metropolitan area. We used surface measurements from thirteen Environmental Protection Administration (EPA) stations in 1994-2006, and one Central Weather Bureau (CWB) station in 1986-2006, along with radiosonde measurement from CWB Banqiao station in 1986-2006 during the Chinese New Year (CNY) and non-Chinese New Year (NCNY) periods.
The 13-station average of EPA showed lower levels of diurnal temperature range, daily maximum temperature and daily mean temperature in the CNY than in the NCNY period, and their differences between the two periods were statistically significant, with differences of 0.61℃, 0.53℃, and 0.22℃, respectively. The CWB data also had lower levels of these three temperature parameters in the CNY than in the NCNY period, though no statistically significant difference was found between the two periods.
Besides, the CWB data showed that cloud amount, sunshine hour, sunshine rate were higher, lower, and lower, respectively, in the CNY than in the NCNY period; their differences between the two periods were statistically significant. We noted that daily minimum temperature, global solar radiation, rainfall and visibility had no statistically significant holiday effect.
The comparison between aerosol (PM10) and meteorological parameters implied a possibility of a semidirect effect on the explanation of the observed holiday effect in the Taipei Metropolitan area. The sounding data of Banqiao station provided a possible, though not strong, evidence for this effect. Overall, during the CNY period, compared to the NCNY period, the concentration of PM10 was lower due to lower vehicle emissions, and the absorption of solar radiation was lower, which resulted in lower air temperature, smaller atmosphere stability, stronger convection, more cloud amount, fewer sunshine hour, lower sunshine rate, lower daily maximum temperature and diurnal temperature range.

並列關鍵字

Holiday effect ； Weekend effect ； Climate variability ； Aerosol ； Semi-direct effect