Analysis Of The Monsoon Contribution In Forming Rainfall Characteristics in Kalimantan As An Effort In Formulating Flood Disaster Mitigation Policies To Support National Security

Abstract

Rainfall plays an important role in human life activities. Floods, landslides, and droughts are the impacts caused by excessive rainfall or no rainfall at all. The characteristics of rainfall are an important factor as a climatological consideration in adjusting and preparing for disasters caused by rainfall. The atmosphere in Indonesia, located in the tropical region, is highly variable and is interference by various atmospheric waves, ranging from daily to decadal periods. National defense and national security are closely related to disaster management because disasters can threaten the sovereignty, integrity, and stability of a country. National security and defense in Indonesia encompass various aspects such as military, political, economic, socio-cultural, and intelligence. Disasters can affect all of these aspects and can threaten national security and defense as a whole. This study aims to determine the characteristics of rainfall in Kalimantan and the phenomena that cause the characteristics of rainfall in Kalimantan, which can be used as one of the considerations in formulating appropriate flood disaster mitigation policies to minimize losses and casualties. The method used in this research is to use descriptive analysis method and literature review (literature review) which the author collects from various sources related to this paper. This method aims to provide a comprehensive and analytical explanation based on data from the literature. The data used in this study are BMKG daily rainfall data for Nunukan, Tarakan, Tanjung Selor, Tanjung Redep, Balikpapan, Samarinda, Kotabaru, Banjarmasin, Banjarbaru, Muara Teweh, Buntok, Palangkaraya, Sampit, Pangkalanbun, Ketapang, Pontianak, Siantan, Nangapinoh, Sintang, Paloh, and Putusibau with the data period 2003-2012 and ECMWF ERA INTERIM 925 HPa with resolution 0.1250 and data period 2003-2012. The methodology used in this research is Make a daily rainfall periodogram with the FFT technique, Make a graph of daily rainfall that is averaged every month, Create a map of wind direction and speed grouped by month, Analyze the periodogram to find the largest period of the rainfall spectrum, Analyze the peak of rainfall on the daily rainfall chart, and Analyze the monsoon winds that affect the peak of rainfall. The results show that Kalimantan's rainfall, with annual periodicity, has 1-2 average daily rainfall peaks spread across Nunukan, Tanjung Selor, Muarateweh, Tanjung Redep, Paloh, Nangpinoh, Putusibau, Sintang, Samarinda Ketapang, Balikpapan, Pangkalanbun, Sampit, Buntok, Palangkaraya, Banjarmasin, Banjarbaru, and Kotabaru. Generally, rainfall with one peak has a higher spectrum density than rainfall with two peaks. Kalimantan's semi-annual periodicity rainfall generally has 2 peaks spread across Tarakan, Siantan, and Pontianak. Then, the Asian monsoon wind greatly affects rainfall in Tanjung Selor, Tanjung Redep, Paloh, Nangapinoh, Putusibau, Sintang, Pangkalanbun, Sampit, Buntok, Banjarbaru, and Banjarmasin. The Asian monsoon transitional wind has an effect on Tarakan, Samarinda, Pontianak, Siantan, and Ketapang. Then, the Australian monsoon wind influences rainfall in Nunukan, Balikpapan, and Kotabaru. By knowing the rain pattern in Kalimantan, it is hoped that it can be used as a basis for consideration in setting policies in mitigating floods. There needs to be more in-depth research on locations that are a national priority, such as East Kalimantan because the area will be a candidate for the National Capital