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Seen from Space 2008

The 40th anniversary, Ogasawara Islands

 
Fig. 1. Ogasawara Islands
Ogasawara Islands, Tokyo (kmz, 2.71MB, Low Resolution) as seen on Google Earth
Figure 1 presents an image of the Ogasawara Islands on the 40th anniversary of the handover to Japan on 26 June, 2008. On the north side is the Chichi-jima (Father Island; chichi means father and jima means island) Group,and on the south side is the Haha-jima (Mother Island) Group. The Ogasawara Islands comprise over 30 large and small islands consisting of the Muko-jima (Bridegroom Island) Group, Volcano Islands Group, Minami-Tori-shima and Okino-tori-shima including the Chichi-jima and Haha-jima Groups. The Chichi-jima Group consists of Chichi-jima, Ani-jima (Elder Brother Island), and Ototo-jima (Younger Brother Island). The Haha-jima Group consists of Ane-jima (Elder Sister Island), Imoto-Jima (Younger Sister Island) and Mei-jima (Niece Island). Their names are very family-like.

The Ogasawara Islands are 1,000km southeast of Tokyo, Japan. They are oceanic islands and volcanic islands like Hawaii and the Galapagos Islands. The Ogasawara Islands have unique ecosystems because they have been isolated from all continents since their formation. Most of the Ogasawara Islands were designated a Japanese National Park in 1972. They are now tentatively listed on the World Heritage list of the United Nations Educational, Scientific and Cultural Organization (UNESCO), and around these islands humpback whale watching can be enjoyed in spring.

The Pacific Plate was overridden by the Philippine Plate 48 to 45 million years ago, and the Muko-jima Islands and the Ogasawara islands were formed by the subsequent volcanic activity in the shallow layer. As the volcanic activity moved south, the Haha-jima Islands were formed by the activity in the deeper layer. With further subduction of the Pacific plate, the volcanic islands including Iou-jima were formed and are still active today. The volcanic islands are located 180km southwest of this image.
Except for Chichi-jima, Haha-jima, and Minami-tori-shima, the islands are uninhabited. Ogasawara has a population of 2,700 (National Census, 2005) and is part of the Tokyo megalopolis.

Fig. 2. Chichi-jima Group
Figure 2 depicts the Chichi-jima Group with its core island, Chichi-jima (24km square). From south to north, the islands are Chichi-jima, Ani-jima, Ototo-jima and Mago-jima. From Takeshiba Pier in Tokyo to Port Futami on Chichi-jima takes twenty five and a half hours by ship. Most of the inhabitants of Chichi-jima live in Omura district, particularly Port Futami, where there are many boarding houses and bed and breakfast facilities.

The beautiful beach visible from offshore Ani-jima extends from Miyanohama on the northern end of Chichi-jima to Nagasaki and Hatsuneura. The sea is home to coral reefs and tropical fish. JAXA's tracking station in the center of the island monitors the flights of rockets launched from Tanegashima Space Center. On a clear day, you can see all around as far as Muko-jima and Haha-jima from Mt. Chuo (central Chichi-jima, 319m above sea level) south of the station.

Kopepe beach and Kominato beach on the west of the island are beautiful white beaches where sea turtles lay their eggs. Boarding houses and bed-and-breakfast facilities dot Nogiyama, Ohgiura and Kominato beaches.

Minami-jima (South Island) on the southwestern end of Chichi-jima is a natural treasure island in the Ogasawara Islands. Sightseeing and trekking tours for viewing various flora and egg-laying sites of sea birds and sea turtles are very popular. However, landing on the island is limited to protect the natural environment.

Fig. 3. Haha-jima Group
Figure 3 depicts the Haha-jima Group with its core island, Haha-jima (20km square). Ane-jima, Imoto-jima and Mei-jima lie in a line south of Haha-jima. It is 50km from Port Futami on Chichi-jima to Port Oki on Haha-jima, requiring a two-hour boat trip.

Several hundred people lived in North Port on the north side of Haha-jima before World War II. A coral reef protects the island, and blue sea turtles inhabit the surrounding sea. The highest peak on Haha-jima is Mt. Chibusa (463m above sea level), and other mountains rise from the center of Haha-jima. Many plants are indigenous to Ogasawara, such as Hahajimanobotan (a type of peony) and wadannoki (wild chrysanthemum). The east beach visible from the mountain top is beautiful, as is the sunset from Shin-yuhi-ga-oka near Inokuma Bay. The present island population is concentrated in Motoji (Okimura and Fujisawa) facing Port Oki south of the island.

Ane-jima, Imoto-jima and Mei-jima are now uninhabited and have become the habitat of native fauna and flora, including the bird "Meguro" (Bonin Honeyeater), a special Natural Treasure of Japan.

Ogasawara has a complicated history due to its geography but has transitioned from comeback and restoration to development and enrichment. New cultural activities, such as the hula dancing of and other dances of South Pacific cultures have now become popular. Memorial ceremonies and carnivals are planned for the 40th anniversary, so please visit Ogasawara.



Explanation of the Images:


(Click the images twice to enlarge.)
Satellite: Advanced Land-Observing Satellite (ALOS) (Daichi)
Sensor: Advanced Visible and Near Infrared Radiometer-2 (AVNIR-2)
Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM, Figs. 2 and 3)
Date: 0117 (UTC) on February 14, 2007 (Figs. 1 and 3, AVNIR-2)
0117 (UTC) on November 17, 2007 (Fig. 2, AVNIR-2/PRISM)
0117 (UTC) on November 17, 2007 (Fig. 3, PRISM)
Ground resolution: 2.5m (PRISM) and 10m (AVNIR-2)
Map Projection: Universal Transversal Mercator (UTM)
AVNIR-2 has four observation bands. The composite images are produced by assigning red to Band 3 (610 to 690nm), green to Band 2 (520 to 600nm), and blue to Band 1 (420 to 500nm). The resulting images have natural coloring as if seen by the naked eye. Thus, the following colors designate ground objects.

Green: Forests
Light green: Grass fields or farmlands
Bluish grey: City area or roads
Light brown: Bare land, developing land, or roofs
Blue: Water surfaces
White: Clouds

Figs. 2 and 3
PRISM is an optical sensor for observing ground surfaces with visible and near-infrared signals in the 520 to 770 nano-meter (one-billionth of a meter) band. The acquired image is monochrome. PRISM has three independent optical systems (telescopes) to acquire images for nadir, forward, and backward views at the same time. Only the nadir image was used in this article.

The AVNIR-2 composite image was then transformed into hue, saturation and intensity, and the intensity was replaced by the PRISM image. The hue, saturation and intensity data were then reversed into a color image, resulting in a virtual 2.5m ground-resolution color image. This kind of high-resolution color image, composed by combining a higher-resolution monochrome image and a lower-resolution color image, is called a pan-sharpened image.

Related Sites:
ALOS Research and Application Page
"The Gathering Place" in the Pacific, Oahu Island, Hawaii
Observing the New Year's First Sun Rising over the Ocean
Land, Seen from Space
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