STUDI KEKERINGAN METEOROLOGI DENGAN MENGGUNAKAN METODE STANDARDIZED PRECIPITATION INDEX (SPI) DAN PERCENT NORMAL INDEX (PNI) DI SUB DAS KADALPANG KABUPATEN PASURUAN

Aini Nurnabilla Dukhosagt, Donny Harisuseno, Ery Suhartanto

Abstract


Pada Kabupaten Pasuruan di tahun 2018, terdapat 20 desa di 5 kecamatan yang ditetapkan sebagai daerah rawan bencana. Maka perlu dilakukan studi analisis indeks kekeringan untuk dapat meminimalkan kerugian dan penanggulangan maupun penanganan bencana sesuai skala prioritasnya. Analisis indeks kekeringan meteorologi menggunakan metode Standardized Precipitation Index (SPI) dan metode Percent Normal Index (PNI). Hasil indeks kekeringan meteorologi kemudian dianalisis kesesuaian dengan indeks kekeringan hidrologi metode Standardized Streamflow Index (SSI) guna mengetahui metode yang lebih sesuai di Sub DAS Kadalpang. Kejadian kekeringan terparah metode SPI pada periode defisit 1, 3, dan 6 bulanan pada tahun 2018 sedangkan pada periode defisit 12 bulanan pada tahun 2004. Untuk metode PNI terjadi sepanjang tahun pengamatan kecuali 2010. Setelah dilakukan analisis kesesuaian, diperoleh hasil korelasi lemah dan hasil kesesuaian yang rendah dengan membandingkan pola dan klasifikasi. Sehingga dilakukan perbandingan pola dengan debit dan curah hujan untuk memperkuat pengambilan keputusan. Perbandingan pola dengan metode PNI memperoleh kesesuaian terbesar, sebesar 69% dan 85%. Hasil peta persebaran kekeringan dalam kurun waktu 20 tahun melanda hampir seluruh desa di Sub Das  Kadalpang yang terjadi pada bulan Juni, Juli, Agustus, September dan Oktober.

In Pasuruan Regency in 2018, there were 20 villages in 5 sub-districts that were designated as disaster-prone areas. So it is necessary to do a drought index analysis study to be able to minimize losses and mitigate and handle disasters according to the priority scale. Meteorological drought index analysis uses the Standardized Precipitation Index (SPI) method and the Percent Normal Index (PNI) method. The results of the meteorological drought index were then analyzed according to the hydrological drought index using the Standardized Streamflow Index (SSI) method to determine which method was more suitable in the Kadalpang Sub-watershed. The worst drought incidence was in the SPI method in the deficit period 1, 3, and 6 months in 2018 while in the 12-month deficit period in 2004. For the PNI method occurred throughout the observation year except 2010. After the suitability analysis was carried out, the results of weak correlation and low conformity were obtained by comparing patterns and classifications. So that the comparison of patterns with discharge and rainfall is carried out to strengthen decision making. The comparison of the pattern with the PNI method obtained the greatest suitability, amounting to 69% and 85%. The results of the map of the distribution of drought over a period of 20 years that hit almost all villages in Sub Das Kadalpang which occurred in June, July, August, September and October.


Keywords


Kekeringan; Standardized Precipitation Index; Percent Normal Index; Standardized Streamflow Index; Peta Persebaran

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