Indonesia is the largest archipelago in the world. It consists of five major islands and about 30 smaller groups. The figure for the total number of islands is 17,508 according to the Indonesian Naval Hydro-Oceanographic Office. The archipelago is on a crossroad between two oceans, the Pacific and the Indian, and bridges two continents, Asia and Australia. This strategic position has always influenced the cultural, social, political, and economic life of the country.

The territory of the Republic of Indonesia stretches from 6°08' north latitude to 11°15' south latitude, and from 94°45' to 141°05' east longitude. The Indonesian sea area is four times greater than its land area, which is about 1.9 million sq. km. The sea are is about 7.9 million sq. km (including an exclusive economic zone) and constitutes about 81% of the total area of the country. The five main islands are: Sumatra, which is about 473,606 sq. km in size; the most fertile and densely populated islands, Java/Madura, 132,107 sq. km; Kalimantan, which comprises two thirds of the islands of Borneo and measures 539,460 sq. km; Sulawesi, 189,216 sq. km; and Irian Jaya, 421,981 sq. km, which is part of the world's second largest island, New Guinea. Indonesia's other islands are smaller in size.

The archipelago is divided into three groups. The islands of Java, Sumatra, and Kalimantan, and the small islands in between, lie on the Sunda Shelf which begin on the coasts of Malaysia and Indo China, where the sea depth does not exceed 700 feet. Irian Jaya which is part of the island of New Guinea, and the Aru Isles lie on the Sahul Shelf, which stretches northwards from the Australian coast. Here the sea depth is similar to that of the Sunda Shelf. Located between these two shelves is the island group of Nusa Tenggara, Maluku, and Sulawesi, where the sea depth reaches 15,000 feet. Coastal plains have been developed around the islands of Sumatra, Java, Kalimantan, and Irian Jaya.
The land area is generally covered by thick tropical rain forest, where fertile soils are continuously replenished by volcanic eruptions like those on the island of Java

CLIMATE AND WEATHER

The climate and weather of Indonesia is characterized by two tropical seasons, which vary with the equatorial air circulation (The Walker Circulation) and the meridian air circulation (The Hardley Circulation). The displacement of the latter follows the north-south movement of the sun and its relative position form the earth, in particular from the continents of Asia and Australia, at certain periods of the year. These factors contribute to the displacement and intensity of the Inter-Tropical Convergence Zone (ITCZ) which is an equatorial trough of low pressure that produces rain. Thus, the west and east monsoons, or the rainy and dry seasons, are a prevalent feature of the tropical climate.

The Main Seasons

The climate changes every six months. The dry season (June to September) is influenced by the Australian continental air masses; while the rainy season (December to March) is the result of the Asian and Pacific Ocean air masses. The air contains vapor which precipitates and produces rain in the country. Tropical areas have rains almost the whole year through. However, the climate of Central Maluku is an exception. The rainy season is from June to September and the dry season from December to March. The transitional periods between the two seasons are April to May and October to November.

Temperature and Humidity
Due to the large number of islands and mountains in the country, average temperatures may be classified as follows:
· coastal plains: 28°C
· in land and mountain areas: 26°C
· higher mountain areas: 23°C, varying with the altitude.

Being in a tropical zone, Indonesia has an average relative humidity between 70% and 90%, with a minimum of 73% and a maximum of 87%.

TERRITORIAL WATERS AND EXCLUSIVE ECONOMIC ZONE

When independence was proclaimed and sovereignty gained, Indonesia had to enact laws to govern the seas in accordance with the geographic structure of an archipelagic state. This, however, did not mean that the country would bar international passage. The laws were necessary instruments for the unity and national resilience of the country, with a territory that embraces all the islands, the islets and the seas in between.

In view of the country’s susceptibility to foreign intervention from the sea and fo domestic security reasons, on December 13, 1957, the Indonesian Government issued a declaration on the territorial waters of the Republic. It stated that all the waters surrounding and between the islands in the territory came within Indonesia’s sovereignty. It also determined that the country’s territorial water limit was 12 miles, measured from a straight baseline drawn from the outermost points of the islands.

In the past, archipelagic states like Indonesia have unilaterally determined their 200 mile Exclusive Economic Zones. Today such economic zones are confirmed by the International Convention on the Law of the Sea, which was ratified by the Indonesian Government on October 18, 1983, by Act No. 5 of the same year. This is the legal basis of the Indonesian Exclusive Economic Zone