Climate anomalies

The geographic nonuniformity of climatic anomalies has important implications for agricultural productivity since some compensation is implied. That is, during a given growing season, good weather and higher crop yields in one... 

By definition, climate is characterized by estimates of meteorological parameters averaged over a time period of 30 years. For instance, climate anomalies for the 1990s are defined as the deviation from averages for the period 1961-1990. Nevertheless, analysis of the spatiotemporal climate variability for individual years is widely practiced. In particular, the World Meteorological Organization (WMO) publishes annual summaries of global climate (Yan and Torres, 2007). 

Edwards M, Beaugrand G, Reid PC, Rowden AA, Jones MB (2002) Ocean climate anomalies in the ecology of the North Sea. Mar Ecol Progr Ser 239 1-10... 

Kiladis, G. N., and H. F. Diaz. 1989. "Global climatic anomalies associated with extremes in the Southern Oscillation." Journal of Climate. 2 1069-1090. 

Various meteorological and proxy records do indicate regional climate anomalies inl783-1784 (e.g., Brififa et al., 1998), but the patterns are not yet well understood or modeled. More generally, it is not clear how readily volcanic plumes generated by fissure and flood basalt emptions can reach, and entrain sulfur into, the stratosphere, and considerable work is still required to understand the circumstances by which effusive activity can compete in the climate stakes with explosive emptions. 

Wang, X., Auler, A.S., Edwards, R.L., Cheng, H., Cristall, P.S., Smart, P.L., Richards, D.A. Shen, C.-C. (2004) Wet periods in northeastern Brazil over the past 210kyr linked to distant climate anomalies. Nature 432, 740-743. 

Our subject of discussion in this chapter is global climate prediction and the uncertainties of such predictions. What do we mean by a prediction of climate E. Lorenz, the father of the chaos theory (Gleick, 1988), once clarified the important difference between forecasts of climate anomalies, such as the one caused by the El Nino phenomenon, and forecasts of the state of climate caused by changes in the solar forcing or by changes in the composition of the atmosphere. The first of these phenomena can in principle be predicted per se with useful skill, while in the second case only changes in the statistical structure of climate can be predicted. We will not be able to say whether a particular summer or winter will be warmer or colder than normal but only say, for example, that the number of summers with a temperature above a certain value will be more common than what it was previously. In this chapter I will use the expression climate prediction only in the context of the ability to simulate or predict the overall statistics of climate. 

However, we still do not know whether characteristic climate anomalies like ENSO and NAO will systematically change in a warmer climate. This cannot be ruled out at present, and in fact some models indicate that the present probability distribution of both ENSO and NAO may be different (Timmermann et al., 1998). Such a change may have more serious consequences for the regional climate than an overall superimposed warming. 

Rhodes L.L., Haywood, A.J., Ballantine, W.J., and Mackenzie, A.L Algal blooms and climate anomalies in north-east New Zealand, August-December 1992, NZ. J. Mar. Freshwat. Res., 27, 419-430, 1993. 

A past climate situation in which changes similar to the present occurred. Used in making climatic projections, climatic anomaly... 

Trouet, V., Esper, J., Graham, N.E., Baker, A., Scourse, J.D., and Frank, D.C. (2009). Persistent positive North Atlantic oscillation mode dominated the medieval climate anomaly. Science, 324(5923), 78-80. 

---