The meteorological impact to the air temperature on a sub-tropical city

This study will center on the meteorological impact of clouds and its influence to the urban air temperature. Quantitative assessment over the behavior and temperature pattern was done using a five-year data of meteorological parameters obtain from the local weather and climate bureau. Urban heat island (UHI) is defined as the increased air temperature of the city over its surrounding sub-urban and rural areas and in this case of a five-year summer period of Taipei, Taiwan were heat temperatures are higher and can go beyond 39°C, acting dominant meteorological cloud cover factor is observe for its effect in temperature pattern. Analysis of local heat characteristics suggests the possibility of the believed theory Urban-scaled greenhouse effect that maybe affecting the patterns of the urban air temperature. An urban-scaled greenhouse effect is a theory that implies; when dense cloud covers the city, most of the supposed released long wave radiation or heat energy is trapped and reflected back by the dense clouds, creating a body of conserved heat that is prolonged in the area. The duration of conserved heat (DCH) is measured by the difference of the diurnal maximum and minimum temperature. To assess the value of the theory the daily cloud amount (CA) and its relationship with the DCH was tested with regression analysis. Calm days with the complete cycle of maximum and minimum temperature accordingly were selected and tested. The five-year average (2008 - 2012) resulted in a regression value of R² = 0.072. Although the years 2011 & 2012 showed a higher regression value of R² = 0.265 and R² = 0.104 respectively, certainly enough the data of years 2011 and 2012 revealed a higher ratio of days with less combination of high wind speed and rainfall which created less fluctuations. Trend pattern for the five summers showed similarities. Some days showed fluctuation but no negative trend of correlation was detected. The heat intensity (HI) is another type of temperature pattern that was observed against CA and DCH, it is characterized by the difference of maximum and minimum diurnal temperature. Suggestive with our analysis, all five-year summertime data of HI showed negative correlation with the CA and DCH, attesting a faster release of long wave radiation when clouds are less.