Alaska and Hawaii; American Pacific Territories - Remote Sensing Application - Completely Remote Sensing, GPS, and GPS Tutorial
Alaska and Hawaii; American Pacific Territories

Having crossed the "48", one might expect the trip to be finished. But, the citizens of the two newest United States would probably be miffed by this apparent overlook. So, we will take off again, to visit Alaska and Hawaii.

Alaska, the 49th state, was admitted to the Union in January, 1959. Here is a nearly complete view of the largest (twice the size of Texas) of these United States, in a color Landsat mosaic (see page 7-3 for an earlier black and white version):

Landsat mosaic of Alaska.

Its key geographic and urban features are shown in this map:

Map of Alaska.

Lets look at the Alaska Range closer up using this Landsat 5 image. Mt. Denali (once named McKinley to honor the assassinated U.S. President, but now called by the Indian name "Denali") at 6160 m (20320 ft) is the highest point in North America. This mountain is treacherous to climb because of sudden, fierce storms; many lives have been lost in the attempt.

Mt. Denali in the Alaska Range; look for it (labeled Denali but in small letters) near the center of the range.

This magnificent peak is impressive from the ground:

Mt. Denali (at left; once named Mt.McKinley) from the ground.

The Brooks Range is the northernmost mountain chain in Alaska. It stands out in this topographic map, which suggests its landforms are created by glaciation. The aerial photo beneath it confirms that observation:

The highest peak in the Brooks Range is Mt. Chamberlain (2749m; 9020 ft). Here is a ground view of this mountain (in the far ridge):

Mount Chamberlain and surrounding peaks.

On the North Slope of Alaska is the great Arctic Wildlife Refuge, which is the scene of years of 'infighting' about whether to open it up for oil and gas drilling or maintain it as a pristine nature preserve, supporting millions of caribou and other game. Here is a MISR image of the Refuge:

The Alaska Arctic Wildlife Refuge; the mountains are the Philip Smith range, the water is the Beaufort Sea; MISR image.

The northernmost town in the United States is Barrow, on the North Slope. It is located in the tundra midst thermokarst lakes. Here it is pictured by an EO-1 Hyperion image:

Hyperion image of Barrow, Alaska.

One of the big three cities in Alaska is Anchorage (the others: Juneau [the capital] and Fairbanks). Locate it in the map above. Here is a SIR-C view:

Radar image of Anchorage, Alaska.

Seen from Cook Inlet, the central part of Anchorage is set off strikingly against the spectacular background of the Chugach Mountains.

Anchorage, Alaska from the ground.

Fairbanks is the home of the University of Alaska. We see it first as a false color satellite subscene, and then from the air:

Fairbanks, Alaska SPOT image; the large stream is the Tanana River.
Fairbanks, aerial view.

The rugged glaciated Chugach mountains extend to the southern coast of Alaska. Part if the range is shown here in this MODIS image:

MODIS image of the Chugach Range.

Here are the Chugach mountains near Port Valdez (where an oil tanker spilled hundreds of thousands of oil, creating a major disaster to wildlife).

Port Valdez in the Chugach mountains.

Just off the bottom right of the above Alaska mosaic, to the south, is the long "panhandle" of Alaska that is nestled against high mountains of the Rocky Mountain chain. Through it run the waterways of the Inland Passage, popular as the main theme of Alaskan Cruises. One destination is Alaska's capital, Juneau, seen here in a Landsat image. Part of the ice field to its east is the Skagway Glacier:

Juneau (purplish patch) near the top of the Alaska Inland Passage; ASTER subscene.

This is Juneau, Alaska's capital, from the ground:

Juneau, Alaska

Alaska is huge - double the area of Texas. It also extends, as part of North America, almost to the latitude of Japan. From Alaska's mainland on the east there is a long, narrow chain of islands known as the Aleutians. These are the best example on Earth of what is known as an Island Arc - a sequence of volcanoes along a classic subduction zone (to the south). Here is a MODIS image of much of this chain, followed by an International Space Station photo of the Cleveland Volcano in eruption, and then a ground photo of a several of the volcanic stratocones:

MODIS image of the Aleutian chain.
The Cleveland Volcano in eruption.
Several of the Aleutian stratocones.

The westernmost village in North America is Unalaska, in the Aleutians:

Unalaska harbor.

The largest of the Aleutian islands is Unimak (4120 km2; 113 km long). It is noted for its active volcano - Shishaldin:

Unimak
The Shishaldin volcano, seen from space.
The symmetrical peak of Shishaldin.

Sometimes the Aleutians are shrouded in fog, but the taller volcanic peaks can rise above this cover, as seen here:

Volcanic peaks rising above the fog.

The westernmost island in the Aleutians is Attu. This is one of two such island occupied for a time by the Japanese Army in World War 2. Today it is home to a radar station. It is also the destination for bird watchers because it is visited by many Asian species but being part of North America a birder can count these on their U.S. life list (the writer, a birder, once planned to go there [by air] in the early 2000s). The island is desolate but one can move around on foot or by bicycle. Here it is from space and from the ground:

ASTER image of Attu, Alaska.
The Aleutians at Attu.

Hawaii was the last state added to the Union, in December of 1959. It is a cluster of many small islands and six large ones. Here is a Landsat mosaic, with a map below it:

The Hawaiian Islands

Best known of its many islands is Oahu, seen in this Landsat image:

The island of Oahu

Using satellite imagery and Digital Elevation Model (DEM) data, this perspective view of Honolulu shows the inlet to Pearl Harbor which, on December 7, 1941 (the "date that will live in infamy"), was partially sealed off by the Japanese sneak attack at dawn that brought the U.S. into World War II:

Perspective view of Honolulu on Oahu.

Honolulu is the capital of the state. We first saw it on page 4-3. Here is its downtown:

Central Honolulu.

Honolulu is the home to the largest U.S. naval base in the Pacific - Pearl Harbor. On December 6, 1941 six battleships were there when the Japanese Navy attacked by air (fortunately, the American aircraft carriers were on manoveurs elsewhere). More than 4000 were killed on the "Day that will live in Infamy" that brought the United States into World War II. Here is a view of Pearl Harbor from space and a ground photo of the U.S.S. Arizona and other ships aflame shortly after the bombing:

Astronaut photo of Pearl Harbor.
Wounded battleships at Pearl Harbor.

The best known natural landmark in Honolulu is Diamond Head, a ring around an extinct caldera, seen here is this aerial view:

Diamond Head, near downtown Honolulu.

The big island of Hawaii is shown in this Landsat image (compare with the one shown on page 17-3):

The Big Island of Hawaii.

As mentioned elsewhere in this Tutorial, the big island is just the latest in the Hawaiian chain to have formed by eruption of basalt from the sea floor. In this region the Pacific tectonic plate is moving northwest. Each island and seamount in the chain resulted when that part of the crust was atop an active hot spot made up of a widespread mantle plume (molten magma that emerges as lava. The center of volcanic activity is Kilauea, whose caldera is shown here:

The Kilauea caldera, with the Mauna Loa shield volcano in the background.

Another of the islands deserves special mention. Molokai is considered the most pristine of the larger islands, having a population around 7000. It was once the home of a famed leper colony, run by Father Damien. It now welcomes tourists.

Landsat image of Molokai.

This image does not clearly show its other claim to fame, indicated by this ground photo.

The cliffs of Molokai.

These are the highest steep cliffs in the world. Internet sites are ambiguous about the actual heights: several cited "greater than 3000 feet"; 2000 feet was also found. The cliffs make up most of the northern shore. Regardless, their origin was as spectacular as the cliffs themselve. Some time in prehistory Molokai was perhaps twice its present size. For reasons unknown, a huge section of the island gave way in a massive landslide, producing the cliffs now seen. Large blocks of the separated land have been found in the ocean tens of kilometers from Molokai.

The United States possesses a widespread collection of atolls and volcanic islands scattered about the Pacific. Several are used as military bases. Here are two views of one that is well known: Guam (it sends delegates to the Republican and Democratic conventions):

Guam as seen from space.
Aerial oblique photo of Guam

Guam appears to be uninhabited in the above two views but it actually has many residences as evident in this Quickbird image, which also shows a golf course:

One of Guam's golf courses.

American Samoa is part of the Samoan Islands (the others are an independent state) in the western Pacific. The American island, with about 60000 residents, was in the news in late September of 2009 because of a tsunami that killed more than 100 of its residents. Here is a space image of Tutuila, the main island, and a ground photo of the harbor near Pago Pago, its main city:

The island of Tutuila.
Pago Pago.

Some American Pacific islands have notably histories in World War II. Midway northwest of the Hawaiian Islands was part of the turning point battle of the Japanese campaign. While it was being attached by Japanese carrier planes, U.S. carriers launched strikes at the Japanese, sinking four of their carriers (the U.S. lost one). The Battle of Midway remains the biggest sea battle ever fought. Midway is actually two islands above water on a larger coral reef.

Midway Island.
Closer view of the Midway air field.

Less well known to most Americans are the islands of Saipan and Tinian in the Marianas in the western Pacific. These belonged to the Japanese at the start of World War II. They were invaded and captured by American marines near the end of that war and have remained in U.S. hands since (they elected to become part of the United States in 1986). It was from Tinian that the B-29 aircraft, the famed Enola Gay, took off to drop the first nuclear bomb ever on Hiroshima in Japan. Here they are as seen from space (Saipan is at the top):

Saipan and Tinian.

With these scenes of the newest of the United States, we end our sojourn across the 48 contiguous United States and the two states beyond. If you have crossed the U.S. before, you can use this tour as a reminder of what you saw. If such a trip is in your future, this tour is a splendid preview of what you could look for. Bon voyage!

But wait! You should really be aiming to become a world traveler. For the U.S., there already is an Atlas of Landsat scenes covering the 48 contiguous states. Would be nice to have a World Atlas composed of Landsat images (except, since up to 11000 are needed to cover all land areas, such an atlas would have more pages the a multi-book Encyclopedia; however, National Geographic has a global Atlas that uses space imagery). To entice you to think "worldwide", the remainder of this Section will take you on a space-based tour of the countries beyond the United States.

To affirm that you have now developed the skills needed to "geographically locate" a Landsat image, we are going to give you another (littler) test. On the next page are 8 full and four partial Landsat scenes, taken from all (except the Antarctic) of the other continents besides North America. They are labeled from A to H. Using any means at your disposal (but a World Atlas is best) try to locate each scene. To help you in this, we will put a few key word hints beneath each image.

So, to proceed with the game, press "Game". This will get you in the proper frame of mind to then pass onto the second part of this Section - the travelogue through the continents that helps you, through looking at various characteristic cities and landscapes, to gain a perspective on the wide varieties of scenery that make up the land surfaces of planet Earth.

Source: http://rst.gsfc.nasa.gov/