Pemodelan prediksi suhu-udara lingkungan (To) :: Kasus koridor Malioboro

WINAKTOE, Wied Wiwoho, Prof. Dr. Sutikno

2008 | Tesis | S2 Ilmu Lingkungan

INTISARI Penelitian ini bertujuan: (a). memformulasi model matematis yang dapat digunakan untuk memprediksi nilai To(simbol) (kondisi terpanas) pada area perkotaan berdasar kasus di kawasan-inti Malioboro, Yogyakarta; (b). mengkaji potensialitas nilai absorbtansi-fasad bangunan terhadap reduksi To di kawasan-inti Malioboro; (c) mengkaji distribusi isotermal To(simbol) pada area perkotaan di kawasan-inti Malioboro guna mengidentifikasi area discomfort. Materi penelitian yang akan diukur mencakup: Y = To(simbol), X1(simbol) = kelembaban relatif (RH), X2(simbol) = velositas angin (Wv), X3(simbol) = kerapatan tajuk (Df), X4(simbol) = tinggi kanopi (Hc), X5(simbol) = height/width (H/W) atau rasio antara tinggi bangunan-gedung dengan jarak di antara bangunan gedung tersebut, X6(simbol) = absorbtansi fasad (αf), X7(simbol) = reflektansi perkerasan (ρp), X8(simbol) = jam observasi (Ho). Pemodelan To dilakukan melalui uji model fit serta asumsi klasik (multikolinieritas, autokorelasi, heteroskedatisitas, serta normalitas). Uji hipótesis tentang penurunan nilai X6(simbol) (αf) berhubungan positip dengan penurunan nilai Y (To lingkungan) dilakukan melalui (a) uji curve fit secara numerik maupun grafik, dan (b) penentuan nilai korelasi sesuai curve fit. Selanjutnya isotermal dilakukan melalui konstruksi (a) weather tool, (b) konstruksi tri-matra, (c) simulasi MRT (Mean Radiant Temperature) pada jam 6.00, 12.00,14.00,15.00,18.00 W.I.B, (d) kalibrasi simulasi MRT, dan (e) penetapan isotermal. Pemodelan To menghasilkan regresi (Y = -0,686X1(RH) – 0,004X2(Wv) – 0,006X3(Df) – 0,063X4(Hc) – 39X5(H/W) – 0,021X6(αf) – 0,069X7(ρp) + 0,092X8(Ho); R2 = 0,624rumus). Korelasi To dengan X6(simbol)(αf) menunjukkan korelasi non-linier (R) = 0,044721, yang berarti tunacocok; implikasinya menyebabkan hipotesis tidak terbukti. Pada isotermal diperoleh konklusi area radiatif juga terjadi pada area terbuka non-koridor sehingga kebijakan Pemerintah Kota Yogyakarta untuk mereduksi To melalui penanaman pepohonan setiap 15 m di koridor kawasan-inti Malioboro sebaiknya diperluas ke ruang terbuka yang berada dalam kawasan-inti tersebut.

This research aims at (a) formulating mathematical model which can be used to predict To(symbol) (the hottest condition) in the urban area based on the case of core-area of Malioboro, Yogyakarta; (b) knowing the potentiality of façade absorbtance value to reduce To(symbol) at the core-area of Malioboro; and (c) knowing isothermal distribution in the core-area of Malioboro to identify the discomfort area. Certain variables involved are Y = outdoor temperature (To), X1(symbol) = relative humidity (RH), X2(symbol) = wind velocity (Wv), X3(symbol) = density of foliage (Df), X4(symbol) = height of canopy (Hc), X5(symbol) = height/width (H/W), X6(symbol) = façade absorbtance (αf), X7(symbol) = reflectance of pavement (ρp), X8(symbol) = hour of observation (Ho). To modelling is constructed through model-fit test and classical-assumption test (multicollinearity, autocorrelation, heteroscedaticity, and normality). Hypothetical testing about positive correlation between the declination of To along with the inclination of X6(symbol) (αf) follows (a) curve-fit test, and (b) correlation value according to the curve fit. Isothermal is simulated through the construction of (a) weather tool, (b) 3-dimension model, (c) MRT simulation at Ho = 6.00, 12.00, 14.00, 15.00, 18.00 W.I.B, (d) calibration of MRT (Mean Radiant Temperature) simulation, and (e) isothermal final-model . To modeling produces (Y = -0,686X1(RH) – 0,004X2(Wv) – 0,006X3(Df) – 0,063X4(Hc) – 39X5(H/W) – 0,021X6(αf) – 0,069X7(ρp) + 0,092X8(Ho); R2 = 0,624formula). Correlation between To and X6(symbol)(αf) shows a non-liniear value (R) = 0,044721 which means that this correlation is weak therefore reject the hypothesis. Isothermal modeling finds that radiative areas are also distributed outside of the corridor then the policy of City Government of Yogyakarta which focusing on the tree plantation along the corridor (separated at 15 m) should be extended towards the open spaces which exist within the core- area of Malioboro.

Kata Kunci : Model To,Perkotaan Malioboro, model, To, urban