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Here’s another chance to play geographical detective! This mystery concerns a particular type of cloud, one example of which was imaged by the Multi-angle Imaging SpectroRadiometer (MISR) in November, 2001. Usually, clouds take their names—cirrus, cumulus, and stratus—from Latin terms that describe the way they appear to someone standing on the ground. But clouds look very different when viewed from space, because satellites can detect, much more easily than a single observer on the ground, “cells” of cloudiness that form on scales ranging from tens to hundreds of kilometers. This image covers an area of 380 kilometers by 325 kilometers over the eastern tropical Pacific. Use any reference material you like and answer the following seven questions about the type of cloud shown in the image. The letters in parentheses associated with the correct answers, when put together, will spell out a relevant word. Submit this seven-letter word as your quiz solution.

1. Two of these statements are false. Which one is true?
   (A) The individual convective cells that collectively make up this cloud structure are quite shallow, with heights generally less than 2 km.
   (T) These cloud systems only occur when the ocean temperature is above 80 degrees F (26.5 degrees C).
   (F) These clouds are usually associated with violent storm systems.
2. Two of these statements are false. Which one is true?
   (U) These clouds are often detected using ground-based radar.
   (C) This type of cloud was first imaged from space in the early 1960’s, soon after the launch of the TIROS V satellite.
   (Y) These clouds are commonly tracked using propeller-driven research aircraft.
3. Two of these statements are false. Which one is true?
   (N) These clouds persist only for a short time when severe weather is occurring.
   (P) Clouds of this type occasionally produce heavy precipitation.
   (T) The organization of these clouds resembles Rayleigh-Bénard convection.
4. Two of these statements are false. Which one is true?
   (H) When these clouds make landfall, they often spawn tornadoes.
   (I) These clouds are often observed to form off the western coasts of continents.
   (N) These clouds form when the atmospheric pressure drops very rapidly, causing condensation.
5. Two of these statements are false. Which one is true?
   (N) These clouds were originally thought to be a transitional form between open and closed cells.
   (E) This type of cloud system plays a major role in the 1939 movie adaptation of a book published in 1900.
   (O) Cloud systems of this type are often given names contributed by Asian-Pacific countries.
6. Two of these statements are false. Which one is true?
   (L) Hail often occurs when these clouds are seen.
   (A) Cloud systems like these are associated with cold ocean currents.
   (O) These cloud systems rarely form near the equator.
7. Two of these statements are false. Which one is true?
   (N) The Coriolis force strongly influences the morphology of these cloud patterns.
   (E) The name describing these cloud forms is also used in conjunction with certain sea creatures.
   (S) The vorticity associated with such clouds can be very dangerous, and when they are seen, you should take cover.

Quiz Rules

Send us your answers, name (initials are acceptable if you prefer), and your hometown by the quiz deadline of Tuesday, March 22, 2005, using the Quiz answer form. Answers will be published on the MISR web site. The names and home towns of respondents who answer all questions correctly by the deadline will also be published in the order responses were received. The first 3 people on this list who are not affiliated with NASA, JPL, or MISR and who have not previously won a prize will be sent a print of the image.

A new “Where on Earth...?” mystery appears as the MISR “latest featured image” approximately once every two-to-three months. New featured images are released on Wednesdays at noon Pacific time on the MISR home page. The image also appears on the Atmospheric Sciences Data Center home page, though usually with a several-hour delay.

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.

Image courtesy NASA/GSFC/LaRC/JPL, MISR Team. Text by Mike Garay (JPL), Clare Averill (Raytheon ITSS/ JPL) and David Diner (JPL).