Analisis Kekritisan Lingkungan berdasarkan Environmental Criticality Index dan Fenomena Urban Heat Island di Kota Bima

Abstract

Konversi lahan vegetasi menjadi lahan terbangun yang terjadi di Kota Bima mendorong terjadinya urban heat island (UHI) dan penurunan kualitas lingkungan yang dapat mempengaruhi kualitas hidup masyarakat dan pembangunan berkelanjutan di Kota Bima. Kekritisan lingkungan dapat diduga menggunakan Environmental Crticality Index (ECI) yang merupakan nilai rasio Normalized Difference Vegetation Index (NDVI) dan suhu permukaan tanah. Pada penelitian ini, ECI dikembangkan menjadi persamaan suhu udara dan Built-up Area Index (BU). Penelitian ini bertujuan mengetahui tingkat kekritisan lingkungan di Kota Bima berdasarkan nilai ECI dan mengetahui hubungan antara UHI dengan ECI di Kota Bima. Analisis dilakukan dengan menggunakan citra satelit Landsat 8 dan pengukuran lapangan. Hasil dari penelitian ini, Kota Bima memiliki kisaran nilai NDVI -0.16 - 0.61 dengan nilai NDVI di perkotaan lebih rendah dibandingkan di pinggiran kota. Kisaran nilai BU -1 - 0.2 dengan BU di wilayah perkotaan lebih tinggi dibandingkan di pinggiran kota. Nilai UHI di Kota Bima tinggi pada tahun 2021. Nilai ECI menunjukan bahwa dari tahun 2015 hingga 2021 lingkungan semakin kritis di wilayah perkotaan. Wilayah pesisir Kota Bima memiliki nilai ECI yang tinggi artinya kondisi lingkungannya telah memasuki kondisi kritis dan juga diidentifikasi terjadi fenomena UHI. Korelasi (r) ECI dengan UHI di Kota Bima cukup kuat (0.36 – 0.55), namun korelasi ECI dengan NDVI dan ECI dengan BU sangat kuat (0.95 – 0.96) dan (0.943 – 0.975).

The conversion of vegetated land into built-up land that occurs in the City of Bima encourages the occurrence of urban heat islands (UHI) and a decrease in environmental quality that can affect the community's quality of life and sustainable development in the City of Bima. Environmental criticality can be estimated using the Environmental Criticality Index (ECI), which is the ratio value of the Normalized Difference Vegetation Index (NDVI) and soil surface temperature. In this study, ECI was developed into an equation of air temperature and Built-up Area Index (BU). This study aims to determine the level of environmental criticality in Bima City based on the ECI value and determine the relationship between UHI and ECI in Bima City. The analysis was carried out using Landsat 8 satellite imagery and field measurements. In this study, Bima City has an NDVI value range of -0.16 - 0.61, with a lower NDVI value in urban areas than in the suburbs. The range of BU values is -1 - 0.2, with BU in urban areas being higher than in the suburbs. The UHI value in Bima City is increased in 2021. The ECI value shows that from 2015 to 2021, the environment is increasingly critical in urban areas. The coastal area of Bima City has a high ECI value, meaning that the environmental conditions have entered a critical condition, and the UHI phenomenon has also been identified. The correlation (r) of ECI with UHI in Bima City is quite strong (0.36 – 0.55), but the correlation of ECI with NDVI and ECI with BU is very strong (0.95 – 0.96) and (0.943 – 0.975).