Sains Malaysiana 45(5)(2016): 689–697

Horizontal Heat Flux between Urban Buildings and Soil and Its Influencing Factors

(Fluks Haba Mendatar antara Bangunan Bandar dan Tanah serta Faktor yang Mempengaruhinya)

HONGXUAN ZHOU, XIAOLIN WANG, YUANZHENG LI, FENGSEN HAN & DAN HU*

State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China

Diserahkan: 12 Jun 2015/Diterima: 3 Disember 2015

ABSTRACT

The soil temperature near four external walls with different orientations was investigated in spring and summer. In both seasons, the soil temperature was higher in the positions closest to the buildings, suggesting that the buildings were a heat source for the soil surrounding them. Therefore, it could be confirmed that there was lateral heat transfer between the soil and the buildings. Based on this, a soil heat flux plate was set between the soil and the buildings to investigate the horizontal heat flux. The data showed diurnal variations of the horizontal heat flux in both spring and summer. In order to determine the factors that influenced the horizontal heat flux and to provide a basis to understand its mechanism, the correlations between the data of several meteorological factors and the horizontal heat flux were analysed. The results showed that solar radiation was significantly correlated with the horizontal heat flux (p<0.0001) in any single season and in the two seasons that were studied. Additionally, other meteorological factors (net radiation, air temperature, relative humidity and soil temperature and moisture) showed strong correlations with the horizontal heat flux on a diurnal scale only. On a seasonal time scale, the correlation might be significant (p<0.0001) as well, but the correlation coefficients decreased too significantly, such as those for soil temperature, air temperature and relative humidity. Alternatively, the correlation might not be significant (p>0.05), such as that for soil moisture. The stepwise regression results indicated that the relative importance of these meteorological factors was 48.63, 21.94, 14.44, 8.12 and 6.87% for solar radiation, soil temperature, air temperature, relative humidity and soil moisture, respectively, on a diurnal scale.

Keywords: Building; construction; horizontal heat flux; soil temperature; urban area

ABSTRAK

Suhu tanah berhampiran empat dinding luar dengan orientasi yang berbeza telah dikaji pada musim bunga dan musim panas. Dalam kedua-dua musim, suhu tanah adalah lebih tinggi dalam kedudukan paling hampir dengan bangunan, menunjukkan bahawa bangunan adalah sumber haba untuk tanah di sekeliling mereka. Oleh itu, ia boleh mengesahkan terdapat pemindahan haba sisi antara tanah dan bangunan. Berdasarkan ini, plat fluks haba tanah telah ditubuhkan antara tanah dan bangunan untuk mengkaji fluks haba mendatar. Data menunjukkan variasi diurnal fluks haba mendatar dalam kedua-dua musim bunga dan musim panas. Untuk menentukan faktor yang mempengaruhi fluks haba mendatar dan untuk menyediakan asas untuk memahami mekanismenya, korelasi antara data daripada beberapa faktor meteorologi dan fluks haba mendatar telah dianalisis. Hasil kajian menunjukkan bahawa sinaran suria telah mempunyai hubungan yang signifikan dengan fluks haba mendatar (p<0.0001) dalam mana-mana musim tunggal dan dalam dua musim yang dikaji. Selain itu, faktor meteorologi lain (sinaran bersih, suhu udara, kelembapan dan suhu tanah dan kelembapan) menunjukkan korelasi yang kuat dengan fluks haba mendatar pada skala yang diurnal sahaja. Pada skala masa bermusim, korelasi mungkin signifikan (p<0.0001) juga, tetapi pekali korelasi menurun terlalu ketara, seperti yang untuk suhu tanah, suhu udara dan kelembapan relatif. Sebagai alternatif, korelasi mungkin tidak signifikan (p>0.05), seperti untuk kelembapan tanah. Keputusan regresi ikut langkah menunjukkan bahawa kepentingan relatif faktor meteorologi adalah 48,63, 21,94, 14,44, 8.12 dan 6.87% masing-masing untuk radiasi solar, suhu tanah, suhu udara, kelembapan dan kelembapan tanah pada skala yang diurnal.

Kata kunci: Fluks haba mendatar; kawasan bandar; pembinaan; suhu tanah

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*Pengarang untuk surat-menyurat; email: hudan@rcees.ac.cn