Mathematical model to help predict drought

June 10th, 2008 - 4:17 pm ICT by IANS  

Sydney, June 10 (IANS) Models developed by a mathematician will take the uncertainty out of predicting droughts and say exactly where and for how long they are expected to occur. The models, named copulas, will help assist farmers determine the viability of different crops and the drought mitigation steps they need to take under varying climatic conditions.

Geraldine Wong of the University of Adelaide has used global climatic indices such as the Southern Oscillation Index (SOI) in conjunction with rainfall statistics to develop the copulas that predict future droughts with a high degree of accuracy.

“The drought over the past two years has cost Australia billions of dollars. This is a big issue for farmers and the nation,” Wong noted.

“If we can forecast in advance the probability of occurrence and the severity of a drought, this will give the rural sector supporting information to help decide on investments such as crops or water allocations.”

The mathematical models are similar to those employed by the financial sector to predict stock market movements.

“Not many hydrologists have used this statistical method until recently, but it can show us the relationship between the severity, intensity and duration of a drought with relative accuracy,” she said.

“In a global sense, a drought means different things to different countries.

“In Asia, for example, meteorologists consider it a drought if there is no rainfall for a couple of weeks. It’s a very subjective term but in Australia’s case, a drought has serious economic and social repercussions,” she said.

“If we can improve the prediction of droughts, this will help mitigate their impact, since farmers can plant more drought-tolerant crops or alter their irrigation needs.

“Water resource managers can also plan contingency arrangements to secure water supply in cities and country towns,” she said.

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