科研之友
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摘要
Oman is one of most water-stressed countries in the world, faced with declining reserves of fresh groundwater and the prospect of decreased natural rainfall due to climate change. A technology that can increase natural rainfall and mitigate the current and future imbalance between Oman's demand and availability of water resources is of major interest. A rainfall enhancement trial using a ground-based ionisation technology was conducted in the Hajar Mountains in western Oman over a period of 170 days (May to October) in 2013. Data for the trial were obtained from 120 rain gauges and two automatic weather stations installed for the trial, as well as data from 11 weather stations operated by the Oman Directorate General of Meteorology and Air Navigation and the daily upper air sounding at Muscat International Airport. The trial employed a crossover design with the two ion emitters operated in a pre-determined randomised alternating schedule. Statistical analysis of the trial data was carried out using spatio-temporal models that used meteorological and spatio-temporal covariates to capture natural rainfall variation, enabling prediction of the level of rainfall that would have occurred if the ionisation emitters had not been operated. This methodology used dynamically defined target and control areas corresponding to two 30-km wide 'corridors' placed symmetrically about each emitter site and oriented downwind along the axis defined by the steering wind direction. Overall, a positive and significant rainfall enhancement effect attributable to the operation of the emitters was observed. The trial was continued in 2014, expanding the trial area to include four ion emitters and 149 rain gauges. Results from this year are also discussed.
- 出版日期2016-6
