Where on Earth...? MISR Mystery Image Quiz #9
Here's another chance to play geographical detective! These four images from the Multi-angle Imaging SpectroRadiometer (MISR) cover the same geographic area but were acquired on four different dates. Each image was acquired by MISR's vertical-viewing (nadir) camera and encompasses an area measuring 257 kilometers x 195 kilometers. North is toward the top.
This mystery concerns a small island located near the western edge of the observed area. In the top two images, the island presents an obstacle to the westerly winds, and wake patterns in the cloud layers are visible downstream of the island's location. In the lower left image, the island is visible within a relatively clear area of open ocean. In the lower right image, the island is partially obscured by cumulus clouds, and a spiral cloud pattern associated with an atmospheric depression is visible in the southeast quadrant.
The Terra satellite, with MISR aboard, flies in a polar orbit and daylight images such as these are acquired as the spacecraft flies from north to south. Terra's orbit is "sun-synchronous", and when the satellite crosses the daylight equator the local time beneath the spacecraft is approximately 10:30 a.m. The four images shown here were processed identically, and relative variations in brightness between the different views have been preserved.
Using any reference materials you like, please answer the following 5 questions:
Answers (added July 17, 2002)
1. The images contain multiple clues that can be used to determine whether the observed area is situated in the northern or southern hemisphere. Name the hemisphere and describe at least two clues you used to establish your answer. (Clues should not make use of knowledge of the island's identity.)
The region shown is in the southern hemisphere. There are 5 clues which can be used to determine hemisphere:
- The clockwise rotation of the decaying cyclonic circulation in the lower right-hand panel;
- Brightness changes between the panels indicate that June is closer to mid-winter (June image appears darker than May image which is darker than April);
- Shadows from cumulus clouds (especially visible in the lower panels) are cast toward the south, thus the sun is north of the clouds;
- The northern sides of these clouds are more brightly illuminated than their southern sides, also indicating that the sun is to the north;
- Shadows are longer in June than in May.
(Note: The westerly wind direction cannot be used as a reliable indicator of hemisphere, and westerlies can curve to the north or south in both hemispheres. Westerly winds do indicate that the region is probably at mid to high latitudes.)
2. Three of the following four statements about the island's environment are true. Which one is false?
(A) Glaciers cover most of the island, and vegetation is limited to lichens and mosses.
(B) The island is of volcanic origin and located at the intersection of oceanic ridges.
(C) A colony of Atlantic puffins makes the island its home.
(D) The highest peak rises more than 750 meters above sea level.
The Atlantic Puffin (Fraterculus arctica) cannot be found here since the Puffin is restricted to the northern hemisphere. This small volcanic island is situated at the intersection of the Mid-Atlantic Ridge (southern extremity), the America-Antarctic Ridge, and the Atlantic Indian Ridge. Vegetation at this permanently glaciated isle is restricted to lichens and mosses. The highest peak (Olavtoppen) rises to 780 meters (2560 feet).
3. Three of the following four statements about the history of the island are true. Which one is false?
(A) Sovereignty over the island was transferred from one country to another sometime between 1918 and 1932.
(B) Steep cliffs make the island difficult to access, and despite many attempts the first landing did not take place until the 1850's.
(C) In the 19th century, a whaling/sealing expedition christened the island with the name of a city located in their native country.
(D) The earliest documented discovery of the island was by an 18th century French explorer, and the island is currently named after this individual.
The island was first sighted in 1738 by French explorer Jean-Baptiste Charles Bouvet de Lozier. Bouvet was convinced it was the northernmost tip of Antarctica but could not circumnavigate or land upon the island due to severe weather. Steep cliffs surrounding most sides of the island also made access difficult, and after various attempts, a landing was made in 1822 by an American sealer, Benjamin Morrell, who named the island after Bouvet. A British whaling/sealing expedition arrived three years later and named it Liverpool Island. The Norwegians claimed sovereignty of the island in 1928, and they renamed it in honor of Bouvet during their expedition of 1929.
4. All five of the following events took place, but only four occurred during the second half of the 20th century. Which one did not occur in this time period?
(A) The island and adjacent waters were designated a nature reserve.
(B) A weather station was established on the island, providing automated temperature and pressure data.
(C) A nuclear bomb test occurred within 3000 kilometers of the island.
(D) An abandoned boat of unknown origin was discovered on the island.
(E) The island's seals were declared to be protected species.
Answer: E (see note below)
(A) Bouvetøya became a Nature Reserve in 1971
(B) An automated weather station was established in 1977
(C) A nuclear bomb was detonated between Bouvetøya and Marion Island in 1979
(D) A lifeboat and supplies were discovered on the island in 1964, but their origin could not be determined.
(E) Seals in the area were declared to be protected in 1935. However, this protection was incorporated into international agreement in 1959.
- Respondents who noted this ambiguity were given credit for this question.
5. What is the name of the island and to which country does it belong?
The island is Bouvet Island (or Bouvetøya) and is a territory of Norway.
37 people from all over the world sent in responses before the deadline. Individuals who answered all five questions correctly are listed below in the order in which responses were received. The prize winners are indicated by asterisks.
1. Antti Kuosmanen, Espoo, Finland*
2. JHG Hendriks, Hintham, The Netherlands*
3. Kathleen Crean, Pasadena, California
4. Robert Korechoff, Pasadena, California
5. Karl Bailey, Mason, MI, USA
6. Mitch Burrill from Purcellville, VA, USA*
7. Kyle Dantzler, Carrollton, TX, USA
8. Patrick B. Phillips, Bismarck, ND, USA
9. Tony MacAdam, Halifax, Nova Scotia, Canada
10. Joe Capuano, Ypsilanti, MI, USA
11. Pam Mitchel and Phil Garwood, Gardiner, ME, USA
12. Chris Martin, Cambridge, United Kingdom
13. Jacques Allemand, Annecy, France
14. Peter Nash, Swinton, South Yorkshire, United Kingdom
15. Yu Wei, Xiamen, China
16. Roy Britten, Christchurch, New Zealand
MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.
Credit: Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
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