La Niña and Mesoamerica
Maria Concepcion DonosoScientist CATHALAC
Republic of Panama
donoso@aoml.noaa.gov
cathalac@sinfo.net
Also, some scientific groups, such as some of our colleagues from Brazil, consider all non-El Niño years as La Niña years, basically making no distinction between normal or cold episodes. This line of thought, I believe is supported by the fact that there is not much difference in the climate between La Niña years and "normal" years for a larger part of their country. This in turn is supported by the fact that no major impacts, or at least not of the size of the impacts associated with El Niño events, are observed/reported during La Niña events.
Very few studies have been carried out on La Niña or on its impact on socio-economic activities in Mesoamerica. Even less has been published. A quick search through our scientific library and ENSO article files did not produce any specific contributions. Surfing the Internet yielded few entries (one of them was the La Niña Summit Home Page) that were related to the climatic event. Personal communications with colleagues from the region provided no input to our quest for La Niña publications, except for a few newspaper articles, some with provocative titles that translate into "If El Niño was bad, wait until you see La Niña" or "Survived El Niño, waiting for La Niña".
Browsing my favorite recently published classics on ENSO, added very little to my quest for information on La Niña and its impacts. George Philander, introduced the term "La Niña" in 1985, and described the physical processes associated with this event in his book "El Niño, La Niña, and the Southern Oscillation." He also presented the interactions between the ocean and the atmosphere, but the Human Dimension of ENSO was not discussed. Glantz (1996) in his book on El Niño's impacts on society, mentioned La Niña in only two sections of his book "Currents of Change," the reason being probably his own statement: "Researchers for the most part have shown less interest in cold events (La Niña) than in El Niño. Perhaps this is because such events are associated with periods of weather and climate conditions that are perceived as normal in various regions" (Glantz, 1996) or "more like an extreme case of the normal pattern" (Glantz, 1991). Diaz and Kiladis (1992) stated that an "aspect of ENSO, overlooked by most workers until the mid-1980s, was the state opposite to El Niño, the so-called La Niña". The beginning of interest in La Niña, at least in the US, may have been motivated by the 1988 La Niña, which was linked to the extensive, severe, and persistent widely publicized and costly North American summer-time drought in 1988. (Glantz, 1991).
Global scale climatic anomalies associated to La Niña are for most part opposite in sign to those seen during El Niño ( Diaz and Kiladis, 1992). For example, in India, monsoon floodings are reported during La Niña events (Parthasarathy and Pant, 1985). Nicholls (1991) also reported flooding in India and eastern Australia, and extreme precipitation in Ethiopia that resulted in flooding in Sudan during the 1988 anti-ENSO (La Niña). Nicholls (1991) correlated outbreaks of Murray Valley encephalitis (MVE) epidemics in southeast Australia with La Niña events. No literature was found addressing La Niña's association with climate anomalies and their subsequent impacts in the region in Mesoamerica.
In conclusion, further work on the impact of La Niña on socio-economic sectors needs to be undertaken. But at the same time, there is a need for a better understanding of the climate variability associated with La Niña. These are particularly necessary and valid challenges for the TC3 region.
Bibliography
Diaz, H. and G. Kiladis, 1992. "Atmospheric Teleconnections Associated with the Extreme Phase of the Southern Oscillation. in H. Diaz and V. Markgraf (eds.), El Niño. Cambridge University Press, pp. 7-28.
Glantz, M.H., 1996. Currents of Change: El Niño's Impact on Climate and Society. Cambridge University Press. 194 pp.
Glantz, M.H., 1991. "General characteristics of El Niño-Southern Oscillation", in M.H. Glantz, N. Nicholls, and R.W. Katz (eds.), Teleconnections Linking Worldwide Anomalies. Cambridge University Press, pp. 1-12.
Nicholls, N, 1991. " Teleconnections and health," in M.H. Glantz, N. Nicholls, and R.W. Katz (eds.), Teleconnections Linking Worldwide Anomalies. Cambridge University Press, pp. 493-510.
Parthasarathy, B., and G.B. Pant, 1985. Seasonal Relationships between Indian Summer Monsoon Rainfall and the Southern Oscillation". J. of Climatology, 5, pp. 369-78.
Philander, G., 1990. El Niño, La Niña and the Southern Oscillation.