1999 EARTH SCIENCE VIDEOTAPES |
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Tape Title | Record ID | Date Produced | TRT: |
Synopsis |
| SCIENTISTS USE SATELLITES TO UNRAVEL LINK BETWEEN RIFT VALLEY FEVER AND EL NINO | G99-064 | 7/15/99 | 00:13:06 | Scientist's first successful prediction of El Nino in 1997 helped save millions of dollars when state authorities wisely prepared for the intense weather. Now scientists have discovered how to read the early signs of an El Nino to help save hundreds of human lives and thousands of livestock in East Africa from a mosquito-borne disease called Rift Valley fever. |
TAPE CONTENTS: |
| ITEM (1): DECIPHERING THE LINK (1980 - 1988) - Scientists have discovered that the combination of the warmer than normal water temperatures associated with El Nino and rising sea surface temperatures in the western equatorial Indian Ocean can trigger outbreaks of Rift Valley Fever in East Africa. The two warm pools of water (highlighted in boxes) increase rainfall in wide areas of eastern Africa which can lead to large-scale outbreaks of the mosquito-borne disease.
Satellites provide synchronous measurements of ocean temperature and vegetation conditions. These images illustrate the close relationship between ocean temperature (warmer than normal ocean colors are shown in red, cooler than normal temps in blue), rainfall, and their impacts on land vegetation (greener than normal vegetation shown in green). Data Source: NOAA AVHRR
Courtesy NASA
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| ITEM (2): DECIPHERING THE LINK (1992 - 1998) - In the early 1980s scientists discovered an episodic cycle of Rift Valley Fever outbreaks dependent upon rainfall. There were large outbreaks every 7 to 10 years, but the virus apparently disappeared between outbreaks. Scientists found that some El Nino episodes over the past five decades resulted in large Rift Valley fever outbreaks. The deciding factor lies in whether the Indian Ocean warms up along with the Pacific. Scientists believe they can now predict episodes of Rift Valley Fever in East Africa six months in advance. Data Source: NOAA AVHRR
Courtesy NASA
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| ITEM (3): DECIPHERING THE LINK (1992-1998) CLOSEUP Data Source: NOAA AVHRR
Courtesy NASA
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| ITEM (4): THE VEGETATION FACTOR - By closely monitoring the vegetation in the region affected by the increased rainfall, scientists can identify the actual areas affected. Scientists use satellite images to show regions of Africa that are greener (and wetter) than normal or more brown (and drier) than normal. Data Source: NOAA AVHRR/ Normalized Difference Vegetative Index
Courtesy NASA
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| ITEM (5): A GLOBAL EL NINO - The segment illustrates the global scale of the massive 1997-1998 El Nino and contains a superposition of sea surface temperature anomalies on anomalies of the sea surface elevation. Warmer than normal temperatures shown in red. Cooler than normal temperatures shown in blue. Data Source: Sea elevation data from NASA/CNES TOPEX/Poseidon, sea temperature data from NOAA AVHRR
Courtesy NASA
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| ITEM (6): THE EVOLUTION AND DECLINE OF EL NINO - The space-based perspective provided by satellite observations trace the evolution of El Nino (shown in red) from its beginning in early 1997 through its decline in early 1998. The onset of La Nina can be seen as the emergence cooler than normal waters (blue) along the equator. Data Source: Sea elevation data from NASA/CNES TOPEX/Poseidon, sea temperatures from NOAA TOGA TAO subsurface temperatures.
Courtesy NASA
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| ITEM (7): B-ROLL SCIENTISTS STUDY SATELLITE DATA OF EL NINO - Scientists at NASA's Goddard Space Flight Center discuss recent satellite data.
Courtesy NASA
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| ITEM (9): INTERVIEW EXCERPT - Assaf Anyamba, Geographer, NASA Goddard Space Flight Center at NASA's Goddard Space Flight Center discuss recent satellite data.
Courtesy NASA
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