Introduction


The Blanket Effect is intended for others to learn about weather modification and its related subjects in an easy to understand way. Started in 2005, this blog is a work in progress as the technology advances

February 21, 2008

Why They 'Seed' Clouds in China

(note: part two is a continuation of a report on Chinese weather modification, translated from Chinese to English. Due to the poor translation, grammatical errors are corrected by The Blanket Effect editor. For the emerging series, click China/Huzhijin link)

Precipitation Enhancement in China: A Developing Technology for Obtaining Additional Water from Sky
PDF
Hu Zhijin
Chinese Academy of Meteorological Sciences



The Precipitation Enhancement (PE) activities in China are mainly aimed at mitigation of the drought damage.

In the North of China drought occurs almost every year and covers a large area, so the PE activities in many provinces are carried out regularly in spring seasons.

In the South of China droughts usually occur in a seasonal and local manner, the PE activities are usually carried out urgently. (image at right outlines natural north/south boundaries, with the Qinling Mountains and Huai River marking the approximate boundary between wheat and rice cultivation, click for detail, from Wikipedia.com)

In recent years, more attention [has been] paid to PE for obtaining additional water in the catchment area of reservoirs or river[s].

This kind of PE activities will be carried out regularly in the wet season, when the cloud condition is much better than that in the drought situation. A PE project in the upper reaches of Huanghe River may be a recent example.

[A] PE operation was also used for prevention of forest fire[s] and [for the] protection of the crops from severe cold, through the increase of snow cover in winter.

Warm cloud seeding was emphasized in [the] 1960's, [when the] introduction of [a] large amount of salt particles in Cucong clouds (Cumulus Congestus) led to some rain-enhancement effects, but there were difficulties in dealing with the large amount of corrosive material.

On account of the most contribution of Cb clouds (Cumulonimbus) to the total rainfall and the high efficiency of the ice forming technology, introduction of ice-forming agent in developing Cb cloud (mainly by artillery shoot) was adopted for rain enhancement through its microphysical and dynamical effects.

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