Analisis Perubahan Vegetasi dan Variabilitas Curah Hujan di Kawasan Taman Nasional Lore Lindu, Sulawesi Tengah

Lore Lindu National Park is the major zone of the Lore Lindu Biosphere Reserve that is located in Central Sulawesi Province. The National Park consists mainly of mountain and sub-mountain forest (± 90%) and a small part of lowland forest (± 10%). Vegetation changes and climate variability in this ecological zone will have a wide impact on ecosystems from local to global levels. Climate anomalies that occur have the potential to cause changes in rainfall variability and vegetation changes. The purpose of this study is to analyze the correlation of Normalize Difference Vegetation Index (NDVI) with rainfall variability in Lore Lindu National Park use the Pearson correlation method. The data used are rainfall data from 2015 to 2017 from several rain posts around the Lore Lindu National Park area, and NDVI data was taken from NOAA satellites using Advanced Very High Resolution Radiometer (AVHRR) sensors. In this study for further analysis used data from two rainfall posts where the average of rainfall has the highest correlation with NDVI changes, namely Doda and Lore Peore rainfall posts. The results of this study show that rainfall is positively correlated to NDVI, which means that rainfall changes are followed by changes in NDVI (changes in vegetation). The highest correlation occurred in Doda rain post, this is due to the location of the Doda rain post which is close to dense vegetation in the Lore Lindu National Park area.Taman Nasional Lore Lindu merupakan zona inti dari cagar biosfir Lore Lindu yang terletak di Provinsi Sulawesi Tengah. Taman Nasional ini sebagian besar terdiri atas hutan pegunungan serta sub – pegunungan (±90%) dan sebagian kecil hutan dataran rendah (±10%). Perubahan vegetasi dan variabilitas iklim pada zona ekologi ini akan berdampak luas terhadap ekosistem dari tingkat lokal hingga global. Anomali iklim yang terjadi berpotensi menimbulkan perubahan varibilitas hujan dan perubahan vegetasi. Tujuan dari penelitian ini adalah untuk menganalisis korelasi Normalize Difference Vegetation Index (NDVI) dengan variabilitas curah hujan di Taman Nasional Lore Lindu menggunakan metode korelasi Pearson. Data yang dipergunakan adalah data curah hujan tahun 2015 hingga 2017 beberapa pos hujan di kawasan Taman Nasional Lore Lindu dan data NDVI diambil dari satelit NOAA yang menggunakan sensor Advanced Very High Resolution Radiometer (AVHRR). Hasil dari penelitian ini menunjukan bahwa curah hujan berkorelasi positif terhadap NDVI yang artinya perubahan curah hujan diikuti oleh perubahan NDVI (perubahan vegetasi). Korelasi tertinggi terjadi pada pos hujan Doda hal ini disebabkan karena letak pos hujan Doda yang berdekatan dengan vegetasi lebat di kawasan Taman Nasional Lore Lindu

Effect of Strong El-Nino and Strong La-Nina Periode on Groundwater Availability in Palembang City

El-Nino results in reduced air mass in most parts of Indonesia and can cause drought. In the La-Nina phase some parts of Indonesia will get more water vapor resulting in increased frequency of rain. Increased rainfall has an impact on  groundwater availability. Groundwater  availability illustrates the condition of water in the soil which is useful in many sectors of life, especially in the agricultural sector. This study aims to see the relationship between the El Nino and La Nina phenomena strongly by using SOI indicators on groundwater availability in Palembang. In the Strong El-Nino phase in 1994 and 1997 the SOI index had a moderate correlation with  groundwater availability of 32% and 39%. In 2015 the correlation of SOI to groundwater avability was 79% indicating a strong relationship. In 2008 and 2011 which was a strong La-Nina phase the SOI index correlation value for groundwater availability was 46% and 45%, respectively, which indicated a moderate correlation.

KARAKTERISTIK SUHU DAN SALINITAS VERTIKAL TERHADAP MASSA AIR SELAMA PERIODE IOD (+) , IOD (-) , MUSIM BARAT, DAN MUSIM TIMUR DI SELAT MENTAWAI

Selat Mentawai merupakan bagian Perairan Barat Indonesia yang secara geografis dilalui fenomena antar tahunan Indian Ocean Dipole (IOD) dan perubahan monsun. Dampak yang ditimbulkan oleh fenomena tersebut terhadap karakteristik massa air, khususnya berkaitan dengan distribusi, stratifikasi dan proses percampuran massa air yang berasal dari Perairan Samudera Hindia menjadi fokus utama penelitian. Lokasi penelitian dilakukan di Selat Mentawai yang secara geografis terletak antara 2,3° – 3,3° Lintang Utara dan 100° – 101,5° Bujur Timur, dimana terbagi dalam 4 periode penelitian yaitu: IOD Positif (+), IOD Negatif (-), Monsun Timur dan Monsun Barat. Kajian dilakukan menggunakan data insitu dari instrumen Conductivity Temperature Depth (CTD) untuk mengukur parameter kedalaman, temperatur, dan salinitas. Analisis data CTD menggunakan diagram T-S yang menunjukan hubungan antara suhu dan salinitas di beberapa kedalaman. Selain itu data model arus yang bersumber dari marine.copernicus.eu digunakan untuk melihat distribusi arus laut secara horizontal. Pengolahan data dilakukan dengan memanfaatkan perangkat lunak Ocean Data View (ODV). Secara umum, hasil analisa diagram T-S menunjukan lapisan termoklin berada pada kedalaman antara 50 sampai dengan 150 meter. Dimana lapisan termoklin saat IOD (-) pada kedalaman (92 – 155 meter) dimana lebih dalam daripada IOD (+) pada kedalaman (77 – 130 meter). Lapisan termoklin saat monsun barat pada kedalaman (92,3 - 155,8 meter) lebih dalam daripada monsun timur pada kedalaman (55,7 – 109,7 meter). Arus laut Selat Mentawai dipengaruhi oleh perubahan IOD dan monsun, dimana saat IOD (-) arah arus dominan dari Barat Laut ke Tenggara dan sebaliknya saat IOD (+) arah arus dominan dari Tenggara ke Barat Laut. Sedangkan pada saat monsun barat arah arus dominan dari Barat Laut ke Tenggara. Sebaliknya saat monsun timur arah arus dominan dari Tenggara ke Barat laut. Karakteristik massa air di Upper Water (0 – 500 meter) wilayah Selat Mentawai terdiri dari Benggal Bay Water (BBW), Subtropical Low Water (SLW), South Indian Central Water (SICW), Indonesian Upper Water, dan Indian Equatorial Water. Sementara untuk wilayah Intermidiate Water massa air yang paling dominan berasal dari Red-Sea Persian Intermediate Water (RSPIW). Pada kondisi IOD +, IOD -, Monsun Barat, dan Monsun Timur tidak terdapatnya perbedaan karakteristik massa air

Identifikasi Borneo Vortex terhadap Dinamika Suhu Permukaan Laut di Laut Jawa

The event of Borneo Vortex is a disruption of the synoptic scale that occurs when the Asian monsoon is active. Borneo Vortex occurs because of the interaction of the Asian monsoon winds with the wind from the southeast in the northwest region of Borneo so that the vortex is formed which can increase rainfall. Related with rainfall, Sea Surface Temperature (SST) becomes one of the factors that influence it. The purpose of this study is to examine the effect of Borneo Vortex on the dynamics of Sea Surface Temperatures in the Java Sea. The impact of Borneo Vortex, SST parameter becomes dynamic and very important to influence the condition of waters in Java Sea. Data used in this research is ERA Interim ECMWF (European Center for Medium-Range Weather Forecast) Reanalysis data in the form of wind component u and v, vortisitas relative, divergence, and specific humidity. Rainfall analysis is done using daily rainfall data of 3B42RT TRMM (Tropical Rainfall Measuring Mission), while SST data uses the data of Visualize NOAA (National Oceanic and Atmospheric Administration) High Resolution Blended Analysis Data. The Sea Surface Temperature analysis was performed using Remote Sensing data from the period of December until February (DJF) 2004/05 to 2014/15. The method used is to find the composite value of each parameter at the time of Borneo Vortex event during the time of research. The results identify that the largest event of Borneo Vortex was in December. With the presence of Borneo Vortex, there is a significant change in vorticity, divergence, moisture transport, rainfall, and SST. The impact of Borneo Vortex can increase rainfall and increase SST in the Java Sea. Borneo Vortex occurred in December January February at the time of an active Asian monsoon in northwest Borneo where there is a synoptic scale disorder in the form of a massive air vortex causing an increase in rainfall and the dynamics of SST tend to rise as well