Kajian pola penyimpangan musim di kabupaten Magelang provinsi Jawa Tengah

Widiyastuti Nurchayati, Prof. Dr. H.A. Sudibyakto, M.S.

2011 | Skripsi | S1 GEOGRAFI DAN ILMU LINGKUNGAN

Tujuan penelitian ini adalah 1) mengetahui pola pergeseran awal musim, 2) mengetahui karakteristik hujan musiman, dan 3) mengetahui kecenderungan hujan musiman di Kabupaten Magelang. Metode yang digunakan yaitu analisis statistik deskriptif dan moving averages 5 tahunan. Analisis statistik deskriptif meliputi nilai; rerata, simpangan baku, variasi, intensitas dan frekuensi penyimpangan hujan musiman. Metode moving averages 5 tahunan digunakan untuk mengetahui kecenderungan hujan musiman. Pemetaan dilakukan untuk mengetahui pola keruangan masing-masing nilai. Data yang digunakan merupakan data sekunder, yakni data hujan harian 24 stasiun hujan yang kemudian dikelompokkan menjadi data hujan musiman dan dipilih 11 stasiun penelitian dengan mempertimbangkan hasil uji konsistensi dan korelasi. Periode data adalah 30 tahun, yaitu tahun 1980 hingga 2010. Hasil penelitian menunjukkan bahwa (1) Adanya pergeseran awal musim pada periode 1990-2009, dan periode 2000-2009 dari periode awal (1980-1999), hingga 3 dasarian pada musim kemarau dan 2 dasarian pada musim hujan. (2) Hujan musim kemarau memiliki sifat lebih beragam daripada musim hujan dengan koefisien variasi rata-rata musim kemarau 0,697 dan musim hujan 0,233. Terdapat hujan orografis di lereng Sumbing dan Merapi yang diidentifikasi dari isohyet tahunan dan musiman. (3) Kecenderungan hujan di Kabupaten Magelang pada musim kemarau cenderung menurun dan pada musim hujan cenderung meningkat. Ketiganya menunjukkan adanya penyimpangan musim di Kabupaten Magelang.

The objectives of this research are; 1) to know dislocation the beginning of season, 2) to know seasonal rainfall characteristic, and 3) to know seasonal rainfall trend at Magelang Regency. The methods that were used in the research were statistical descriptive analysis and moving averages during 5 years. Statistical descriptive analisys consist of value of mean, standard deviation, variation, intensity and frequency of seasonal anomaly. The purpose of moving averages during 5 years was to know seasonal rainfall trend. The mapping was used by the author to know the spatial pattern of each values. Secondary data, such as daily rainfall data which was obtained from 24 rainfall stations, further it was grouped into seasonal rainfall data sets and then it was chosen 11 stations based on the result of consistency and correlations. The data was used for this research had the observation period of 30 years, which was started on 1980 until 2010. Based on the objectives of this research, the result show; (1) There is a change in the beginning of the season in 1990-2009, and 2000-2009 from the first periode (1980-1999), until maximum early or late 3 tendays at dry season, and 2 tendays at rainy season. (2) Dry season rainfall has much more variation than the rainy season which has the variation coefficient is 0, 697 and 0, 233. There is orografic rain in the slope of Sumbing and Merapi identified from the isohyets, yearly and seasonly. (3) Rainfall tendency in Magelang at dry season decreases and in the rainy season tends to increase. Those data sets show that there are seasional anomalies in Magelang Regency.

Kata Kunci : Hujan, Musim, Magelang,Rainfall, Season, Magelang