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It certainly has been a funny old year weather wise. Most Kiwis have some idea of El Nino and La Nina and their ramifications, even though they can be mysterious at times. Now we have the phenomenon of the reverse Antarctic oscillation, whereby all those cold fronts that are normally kept south in the summer have been sent spinning northwards to totally confound our whole season. Why this actually happens has never been adequately explained. However people from all sides of the political spectrum generally believe that the timing of this phenomenon, just after Don Brash’s speech at Orewa, is purely coincidental. While the weather pattern has been a life saving drought breaker in many parts of the South Island, and an unexpected boon to growth in the Waikato, the floods in the lower North Island have been horrific and it will take considerable time for the region to be back on its feet again economically. Some of the more subtle effects have been other areas of agriculture, in particular facial eczema and spore counts. Late last year the Alpha-Scientific Newsletter, the Bullet, had an intriguing piece on the effects of El Nino and La Nina on spore counts. |
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the river in some cases, and so most of the country can breath easily for the time being as the risk of facial eczema outbreaks has diminished. However liver enzymes were still very high in some areas, reflecting the fact that many cows were affected by the extreme spore count levels before advent of the heavy rain. March was another month of unsettled weather but there is still risk through to early May. Grass minimum temperature will stay relatively warm and it will not take much in the way of fine weather, with all the moisture in the soil, coupled with a humid atmosphere for nature to force another little kick before the danger period is over. Perhaps the only real risk now is complacency as winter chills seem to have arrived much earlier than normal.
Inside this issue:
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Their records over the years have shown that spore counts are dramatically higher in El Nino years, with the extremely bad facial eczema year of 1999 being a strong El Nino year. The prediction for this year was that it would be an intermediate year weather wise, between El Nino and La Nina, and so the risk of facial eczema would be a moderate one. However the only thing certain about our weather is the uncertainty. At the end of January the climate was warm, stormy and, in the North anyway, extremely humid. These are ideal conditions for growth of Pithomyces chartarum and spore counts in the last week of January were spiraling out of control. The whole country was on a ‘red alert’ for facial eczema and some clinical cases actually started to appear in some areas, even though it was earlier than normal. It looked as if 2004 would be a year to rival 1999 for facial eczema outbreaks. Just as concern was mounting dramatically along wanders the reverse Antarctic oscillation and the torrential rains of February. These have had the effect of washing the spores into the ground, even down |
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