LUAS TUTUPAN VEGETASI DAN VARIASI INDEKS KENYAMANAN TERMAL PADA TAHUN 2002 DAN 2014 DI KAWASAN PERKOTAAN YOGYAKARTA

ADI TRI UTOMO, Mukhlison, S.Hut.,M.Sc.

2016 | Skripsi | S1 KONSERVASI SUMBER DAYA HUTAN

Areal tidak terbangun di perkotaan atau disebut ruang terbuka hijau merupakan salah satu yang terkena dampak oleh urbanisasi. Perubahan luas tutupan vegetasi pada ruang terbuka hijau berdampak lurus terhadap perubahan kualitas iklim mikro seperti kenyamanan termal. Kepadatan jumlah penduduk perkotaan juga berdampak lurus terhadap peningkatan suhu udara di perkotaan, yang berakibat tingkat kenyamanan menurun sehingga produktivitas penduduk perkotaan terhambat. Penelitian ini bertujuan untuk mengetahui luas tutupan vegetasi dan variasi indeks kenyamanan termal di Kawasan Perkotaan Yogyakarta berdasarkan citra Landsat. Luas tutupan vegetasi pada tahun 2002 dan 2014 di Kawasan Perkotaan Yogyakarta (KPY) ditentukan menggunakan metode NDVI (Normalized Difference Vegetation Index), yaitu dengan formula NDVI = (NIR-red)/(NIR+red), dengan NIR adalah spektrum inframerah dekat dan red adalah spektrum merah pada citra Landsat. Sementara itu, variasi indeks kenyamanan termal diklasifikasikan berdasarkan nilai THI (Temperature Humidity Index). Nilai THI 21-24 (nyaman), 24-27 (cukup nyaman) dan >27 (tidak nyaman). Formula THI =0,8t + ((RH x t)/500), dengan t adalah suhu dan RH adalah kelembaban relatif. Dari hasil penelitian diketahui luas tutupan vegetasi di KPY pada tahun 2002 sebesar 51,92 Km2 atau 28,39%, berkurang sebesar 3,98 Km2 atau 2,17% pada tahun 2014 menjadi 47,94 Km2 atau 26,22%. Namun sebaran tutupan vegetasi yang mendekati 30% tersebut tidak merata di seluruh KPY. Sementara itu, variasi indeks kenyamanan termal (THI) di KPY pada tahun 2002 dikategorikan tidak nyaman sebanyak 3 kecamatan, dan dikategorikan cukup nyaman sebanyak 20 kecamatan dengan rata-rata nilai indeks 26,76. Selanjutnya, pada tahun 2014 wilayah KPY dikategorikan tidak nyaman sebanyak 17 kecamatan dan dikategorikan cukup nyaman sebanyak 6 kecamatan, dengan rata-rata nilai indeks 27,58.

Areal which not be constructed in urban can be called the green open space, that is one of some place which affected by urbanization. The changes of vegetation cover extents in green open space is has straight impact to the changes of the micro climate quality, it is like thermal discomfort. Urban population density also has a straight impact to enhancement of urban air temperature, which it can be affected to thernal discomfort so the productivity of urban population is hampered. The aims of this research is to know the extents of vegetation cover and the variation of Temperature Humidity Index (THI) in Yogyakarta urban agglomeration based on Landsat image. The extents of vegetation cover in 2012 and 2014 at Yogyakarta Urban Agglomeration (KPY) has been determined use NDVI (Normalized Difference Vegetation Index) method, the formula is NDVI = (NIR-red)/(NIR+red), which NIR is a near infrared spectrum and red is red spectrum in Landsat citra. Meanwhile, variation of Temperature Humidity Index is classified by the value of THI. The value of THI from 21-24 it is classified as comfortable, from 24-27 is classified as quite comfortable, and >27 is classified as not comfortable. The formula of THI is THI =0,8t + ((RH x t)/500), which t is a temperature and RH is relative humidity. Based on the research result is known that the extents of vegetation cover at KPY in 2002 is 51,92 Km2 or 28,39%, that is decreased 3,98 Km2 or 2,17% in 2014 which is 47,94 Km2 or 26,22%. However the distribution of vegetation cover which close to 30% is not equally in all of KPY. Meanwhile, variation of Temperature Humidity Index at KPY in 2002 it is categorized as not comfortable as much as three districts, and categorized as quite comfortable as much as 20 districts with the mean of index is 26,76. Then, in 2014 the area of KPY which categorized as not comfortable as much as 17 districts and categorized as quite comfortable as much as six districts, with the mean of index is 27,58.

Kata Kunci : Kawasan Perkotaan Yogyakarta, ruang terbuka hijau, ndvi, kenyamanan termal