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British hay fever maps

Hay fever maps have been produced to help sufferers identify ‘hotspots’ that should be avoided. The map locates plants that can trigger hay fever or asthma attacks across Britain. It is hoped the map will help sufferers make decisions about where to live, work or visit at certain times, by also identifying the peak times when pollen is released. The researchers from University of Exeter, the Met Office and NERC’s Centre for Ecology and Hydrology, examined 12 key plant species that are associated with hay fever and asthma and mapped the data across Britain.

Dancing cyclones: The ‘Fujiwhara effect’

The Fujiwhara effect is a rare phenomenon that sees nearby cyclones ‘dancing’ round each other. In July it was seen not once, but twice*: Hurricanes Hilary and Irwin rotated round each other in the Eastern Pacific Ocean off the coast of Mexico generating high surf for Southern California; whilst thousands of miles away in the western Pacific east of Japan just days earlier, Typhoon Noru and Tropical Storm Kulap spun round each other*.

Damp or dry? Measuring humidity

Measuring humidity is easier than you might think, especially with modern day instruments.

Humidity is the amount of water vapour, an invisible gas, in the air. Warm air can ‘hold’ more water vapour than cold air; in fact air at 35°C can hold six times more water vapour as air at 5°C. All meteorological instruments measure the relative humidity (RH); this is the amount of water vapour in the air compared to the amount required to saturate it, given as a percentage - so completely saturated air has a RH of 100%.