The Sunday Mail
Grace Kaerasora
The Meteorological Services Department is cloud-seeding to mitigate below-normal rainfall during early summer cropping, with Treasury channelling US$400 000 towards the exercise.
Two new aircraft are being used in the countrywide programme for which Finance Minister Patrick Chinamasa had budgeted US$500 000.
One aircraft is covering Mashonaland, Manicaland and parts of Midlands while the second is assigned to Matabeleland and Masvingo.
About 75 percent of Zimbabwe received normal rainfall between November 2017 and January 3, 2018, and cloud-seeding will likely increase precipitation.
MSD head (Public Weather Service), Mr Tich Zinyemba told The Sunday Mail: “The Meteorological Services Department is using two aircraft for the exercise in order to reduce flying time to target areas as well as (to maximise) on capturing as many rain-pregnant clouds as possible.
“One aircraft is based in Harare, covering all the Mashonaland provinces, Manicaland as well as parts of Midlands. The second aircraft is positioned in Bulawayo to cover the Matabeleland provinces, Masvingo as well as parts of Midlands.”
On the rainfall update, Mr Zinyemba said: “. . . The bulk of Mashonaland West Province, Mashonaland Central Province (Mazowe through to Mvurwi, Guruve and Mount Darwin), much of Midlands Province (stretching from Kwekwe through Mberengwa to Zvishavane), much of northern Masvingo Province (and) south of Manicaland Province (Chimanimani to Chisumbanje) have received less of their usual rain.”
Zimbabwe Commercial Farmers’ Union president Mr Wonder Chabikwa said: “This season has been displeasing as there is not enough water and as farmers, we have been wondering whether what we are experiencing is a mid-season drought.
“Therefore, cloud-seeding becomes handy when it comes to mitigating this; grazing and stocking up our dams, even for the winter cropping season.”
Zimbabwe Farmers’ Union executive director Mr Paul Zakariya added: “We applaud efforts being made because this season has already proved tough with erratic rains and, in some cases, not enough moisture to cause germination.
“The high temperatures also can only spell a negative outcome towards output such that every effort put towards salvaging the situation is welcome.”
Seeding is a deliberate process that introduces precipitation-inducing particles known as ice nuclei into clouds.
These particles have an ice crystal structure and enable clouds produce precipitation by freezing super-cooled liquid water. Natural ice nuclei are often insufficient within the atmosphere; therefore, adding more through seeding can boost precipitation in clouds. Some clouds contain little ice particles to efficiently convert their super-cooled water into precipitation, and seeding’s artificial ice-forming substances help.
Experts say cloud-seeding increases rainfall by 20-30 percent.
In the 2001-02 summer cropping season, for instance, Zimbabwe received up to 20 percent of its rainfall from cloud-seeding.
The programme has run yearly since 1980 — except for four years — and has variably helped the country overcome dry spells which, in recent years, have been directly linked to climate change.
The MSD forecast normal-to-below-normal rainfall in the early stages of 2017-18 summer cropping and normal-to-above-normal rainfall thereafter.
