Saturday, March 03, 2007

Climate cooling Real world at odds with computer games

The important reality of climate forecasts over extended timeframes are at best an educated guess of the possibilites of the future.These are not predictions of accuracy beyond what a non scientifc prediction based on random coin tosses etc.

As Niwa says ordinary weather forecasts of conditions for a particular day cannot be usefully extended beyond about a week, because of the chaotic nature of the atmosphere. However it is now becoming clear that in some regions and under some existing climate conditions (e.g. during an El Niño) , useful predictions can be made of the likelihood of particular climatic conditions in a future month or season . (Such predictions might indicate, for example, whether the season is likely to be warmer, colder, wetter or drier than average).

Research reported in a paper by Dr John Kidson suggests that about half of the variability in New Zealand seasonal temperatures might potentially be predictable, while the remaining half is inherently unpredictable since it arises from the random, chaotic nature of the atmosphere. The scientific methods and knowledge available to us today can only reach part of the potential 50% predictability.

Mean summer temperatures were well below average. The national average temperature of 15.7°C was 0.9°C below normal and the lowest for summer since 1992/93. December was particularly cold. Summer temperatures were as much as 1.5 °C below average in quite a few eastern areas from coastal Wairarapa to North Canterbury, as well as parts of King Country and Wellington. However, summer temperatures were near average in Nelson. Rainfall was below normal in the west of the North Island from Auckland to Taranaki, as well as Eastern Bay of Plenty, and much of the north, west, and south of the South Island, with less than 50 percent (half) of normal in parts of Waikato, Marlborough, and Otago. By the end of summer severe soil moisture deficits had developed in most eastern areas of both islands from Gisborne to Otago, and spread to Auckland, Waikato, Eastern Bay of Plenty, Wanganui, Manawatu, Wellington, and Nelson. Above average summer rainfall occurred in parts of Northland and Canterbury. Sunshine hours were above normal in Northland and Westland, and below normal in South Taranaki and North Canterbury. The overall summer climate pattern was dominated by more anticyclones in the south Tasman Sea producing more frequent cool southerly winds over the whole of New Zealand. At the same time, seas around New Zealand were about 1°C below normal.

As we stated here the expertise and qualitative attributes of high energy physics is not part of climate scientists technical ability,it is not correctly assimilated into the GCM by parametization of coupled energy equations ie the models suggest closed sets with a “steady state universe in thermodynamic equilibrium”

Atmospheric scientists tend to divide the gaseous regions above a planet into two broad categories called simply lower and upper atmosphere. For Earth, the study of the lower regions (troposphere and strato-sphere) form the discipline of meteorology. The study of the upper regions (mesosphere, thermosphere, exosphere) and their ionized components (the ionosphere) form the discipline of aeronomy. The negative aspect of such a two-fold division is that it encourages thinking of the various atmospheric-spheres as isolated regions of self-contained physics, chemistry, and (in the case of Earth) biology. In reality, there is consider-able coupling from lower to upper regions, an aspect of aeronomy fully appreciated only in the last decade. Com-plimenting this external influence from below, an upper atmosphere has long been known to experience forcing and coupling to and from regions far above it. Aeronomy thus deals with one of the most highly coupled systems in space science --- with neutrals, plasmas, and electromagnetic processes that link the planets, moon, and comets from their surfaces to the solar wind and ultimately to the Sun itself.


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