Chapter
5
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The 1997-1998 El Niño:
Images of Floods and Drought
Cynthia A. Evans, Julie A. Robinson, M. Justin Wilkinson,
Susan Runco, Patricia W. Dickerson,
David L. Amsbury, and Kamlesh P. Lulla
Office of Earth Sciences
NASA Johnson Space Center
Houston, Texas USA
Abstract
Astronauts and cosmonauts on the Mir Space Station had an unprecedented opportunity to photograph and present a global view of the effects of the 1997-1998 El Niño from July 1997 through May 1998. Their photographs document both the local effects and the supraregional extent of weather anomalies in areas where El Niño conditions have traditionally been reported, such as Southeast Asia, Australia, and northern South America. Significantly, effects of weather anomalies were also documented in regions far from the equatorial Pacific, such as southern Canada/northeastern United States, southern Africa and northeastern Africa. Progressive drought in Southeast Asia, Australia, the Andean Altiplano, northern Brazil and South Africa is expressed in lower lake, reservoir and river levels and increased biomass burning. Abnormally high levels of rainfall and snowpack in typically arid regions of the southwestern U.S. and northeastern Africa are reflected in unusually green vegetation and higher lake and river levels. Minimal sea ice in the Gulf of St. Lawrence attested to the unusually warm winter there.
Citation for the published article
Evans, C. A., J. A. Robinson, M. J. Wilkinson, S. Runco, P. W. Dickerson, D. L. Amsbury, and K. P. Lulla, 2000. The 1997-1998 El Niño: Images of floods and drought, in Dynamic Earth Environments: Remote Sensing Observations from Shuttle-Mir Missions (K. P. Lulla and L. V. Dessinov, eds.), John Wiley & Sons, New York, pp. 61-76, 262-263, 272-274.
Links to Color Images
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Figure 5.1
Sea surface temperature anomaly map, December 8, 1997. (From Fleet Numerical Meteorology and Oceanography Center, 1998). Precipitation anomalies estimated to be within the driest or wettest 10% of climatological occurrence between November 1997 and January 1998 have been plotted on the map. (Modified from Climate Prediction Center, 1998.) Regions affected by El Niño weather that are discussed in this chapter are marked by arrows connected to the text boxes. The temperature scale is in degrees Celsius. Mission durations are: NASA 5 from May to September 1997; NASA 6 from September 1997 to January 1998; and NASA 7 from January 1998 to June 1998. |
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Figure 5.2
Severe flooding in the Paraná drainage of northern Argentina and Uruguay can be seen in this early January 1998 view (NASA photograph NASA6-710-077). The photo looks west over the Rio Meriñay (foreground) and the Paraná (under the solar panel). Sunglint highlights the immense area covered in water - the edges of the normal river drainages can barely be discerned in the larger flooded river valleys (arrows). Salto, Uruguay is just off the edge of the image to the lower left. The graph shows the regional precipitation deviations due to El Niño. The cumulative observed precipitation is given by the heavy solid line, and normal precipitation (cumulative) is depicted by the thin dashed line. The bar indicates when the photo was taken. (Modified from the Climate Prediction Center, 1998.) |
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Figure 5.3
Dry season in Brazil. This photograph (NASA photograph NASA5-705-080) looks southeastward over Lake Titicaca in the Peruvian-Bolivian Andes (foreground) and Lago Poopó (Bolivia) toward the smoke-induced haze of Brazilian and Bolivian lowlands. The late July 1997 Amazon smoke pall, the result of biomass burning in the Amazon Basin during the dry season, is the light haze filling the background. The smoke finds its way up valleys from the basin even into the upper reaches of the Andes (center left of the image). The dry season in parts of the Amazon basin was unusually severe in 1997, which has been attributed to El Niño. The graph below the photo shows the regional precipitation deviations due to El Niño. The cumulative observed precipitation is given by the heavy solid line, and normal precipitation (cumulative) is depicted by the thin dashed line. The bar indicates when this photo and the photos in Figure 5.4 were taken. (Modified from the Climate Prediction Center, 1998.) |
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Figure 5.4
This series of photos of Lago Poopó shows how rapidly the lake dried up during the 1997-1998 El Niño. This shallow lake in the Bolivian Andes is very responsive to climate shifts. The extreme fluctuations in water levels can be used as a visual indicator for relative rainfall in the region. The view in the upper left (NASA photograph NM23-714-627) was taken in March 1997 after unusually wet weather in the high Andes - up to 200% of normal - had flooded Lake Poopó (arrow), and nearby salars Uyuní and Coipasa (just right of center) for the first time in years. The photo in the upper right (NASA photograph NASA5-705-085) shows Lago Poopó in late July 1997. By November 1997 the "thumb" on Poopó had completely evaporated (lower left, NASA photograph NASA6-710-082). The lower right photo, taken in May 1998, completes the time series and shows that the lake is almost completely dry (NASA photograph NASA7-726-036). A chart showing regional cumulative precipitation over this time period is provided in Figure 3. |
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Figure 5.5
Graph of water areas in Lago Poopó and Salar de Coipasa, Bolivia. The data were mapped from photographs taken by astronauts and cosmonauts. The gaps represent periods for which no data are available. The El Niño events are indicated by shading in the background |
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Figure 5.6
The first photo from the Shuttle-Mir program to visibly portray early El Niño impacts was taken during the STS-86 mission in September 1997, as Dave Wolf was exchanging places with Mike Foale (NASA ESC image S86E5087). The Electronic Still Camera on the Shuttle, controlled by middle school students involved in the KidSat project (KidSat, 1997), was used to create a photomosaic of the smoke pall covering southern Sumatra. This is one of these images showing a corner of the smoke pall covering the southern tip of Sumatra. The white arrows mark some of the individual smoke plumes, the dark arrow points to dense smoke with gravity waves, which could be mistaken for cloud. The graph shows the regional precipitation deviations due to El Niño. The cumulative observed precipitation is given by the heavy solid line, and normal precipitation (cumulative) is depicted by the thin dashed line. The bar indicates when the photo was taken. (Modified from the Climate Prediction Center, 1998.) |
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Figure 5.7
Lake Eyre in south-central Australia responds to El Niño events by drying up. These photos of Lake Eyre were taken in July 1997 (NASA photograph STS094-748-083), January 1998 (NASA photograph STS089-717-055) and April 1998 (NASA photograph NASA7-714-014) and depict the dropping water levels in Lake Eyre due to the regional, El Niño-induced drought. The graph below the photo shows the regional precipitation deviations due to El Niño. The cumulative observed precipitation is given by the heavy solid line, and normal precipitation (cumulative) is depicted by the thin dashed line. The red bars indicate when the photos were taken. (Modified from the Climate Prediction Center, 1998.) |
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Figure 5.8
Coastal Somalia in March 1996 and January 1998. The 1998 view (NASA photograph NASA6-708-056), taken after the heavy rains, shows remarkably green vegetation over this normally arid region. It contrasts with the brown, more normal view, taken in March 1996 (NASA photograph NM21-727-006). The large light-colored patches on the coast are dune fields. The graph shows the regional precipitation deviations due to El Niño. The cumulative observed precipitation is given by the heavy solid line, and normal precipitation (cumulative) is depicted by the thin dashed line. The bar indicates when the NASA 6 photo was taken. (Modified from the Climate Prediction Center, 1998.) |
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Figure 5.9
Heavy rains from December through April along the central California coast supported significant growth of the regional vegetation, which gave this section of California an unusually green cast. This image (NASA photograph NASA7-709-029), taken in March 1998, centers on San Francisco Bay. The urban region around the bay contrasts strongly with the green vegetation on the surrounding hillsides. The graph shows the regional precipitation deviations due to El Niño. The cumulative observed precipitation is given by the heavy solid line, and normal precipitation (cumulative) is depicted by the thin dashed line. The red bar indicates when the photo was taken. (Modified from the Climate Prediction Center, 1998.) |
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Figure 5.10
These two views compare the ice on Lake Erie on (A) February 20, 1997 and (B) February 25, 1998 (NASA photographs NM22-773-083 and NASA7-707-049). View (B) looks south over the lakes toward the Chesapeake on the horizon. Sunglint highlights the water. The box shows the approximate area covered in view (A). Despite regional snow cover, no ice covered the eastern Great Lakes in February 1998 when view (B) was taken. |
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Figure 5.11
A visual marker for the unusually mild winter over the northern United States and southern Canada was the lack of an extensive ice cover on the St. Lawrence Seaway. An early January 1998 view of the Isles de la Madeleine (NASA photograph NASA6-708-003), usually icebound by midwinter, contrasts with a February 1997 regional view (NASA photograph NM22-778-081), which shows extensive ice cover in the southeastern Gulf of St. Lawrence between Newfoundland (foreground) and Nova Scotia (left of center). The arrow points to the Isles de la Madeleine. |
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Figure 5.12
Fires burning out of control in central and southern Mexico and Central America created a regional smoke pall that covered much of Central America and extended into the Pacific and Caribbean region and as far north as Canada. This view (NASA photograph NASA7-726-009) was taken near the height of the fires in mid-May 1998. It looks north from Nicaragua in the foreground toward Mexico at the top; smoke extends to the horizon. |
