level 2

13日洋洋洒洒一整天的小雨雪,给市民带来不少惊喜。但由于天气过程中云层太低太薄,到不到高射炮发射云层的厚度,人工增雨[1]未能如期实施。

山东省潍坊市[2]人工影响天气办公室郑学山介绍说,人工增雨要有适合的天气条件,空中要有充足的云水资源,还要有适合降雨的天气动力条件,只有满足这两个基本条件,各种增雨设备才能将催化剂[3]送到云层中,并产生作用。此次降水过程冷空气太强,且云层厚度高度也不"达标"。"高射炮和火箭发射需要45度角,需要的云层至少在3000米以上高度,但这次冷空气过程,云层最高才2000米,达不到实施人工降雨的条件。"

郑学山告诉记者,发射里程不到,高射炮和火箭打不到云层里去,催化剂起不到作用,对地面的居民安全也有影响。

潍坊市人工影响办公室的工作人员两个月前就做好了人工增雨的准备,却迟迟无法实施,此次冷空气交汇过程,工作人员从13日凌晨开始一直实时关注天气情况,但云层条件始终不如意,最终只好放弃"借水计划"。

气象[4]专家介绍,把天上的水实实在在地降到地面上来,不让它白白跑过去,这就是人工降雨。其有空中、地面作业两种方法,空中作业是用飞机云中播撒催化剂,地面作业是利用高炮、火箭从地面上发射。但也不是想增多大就能增多大,有统计显示,正确运用人工催化技术,可最多开发云中20%的降水量。

据了解,人工增雨原理可概括地用"触发机制"四个字来描述,即在充分研究自然降水过程的基础上,人工触发自然降雨机制。有云才能有雨,但不是所有的云都有降水潜力,只有那些有降水潜力和开发利用可能(云水资源丰富,云层较厚,对冷云来讲主要要有较丰厚的过冷水区)的云才可催化致雨。

13日凌晨,山东潍坊迎来今冬首场降雪。记者从山东省潍坊市气象局获悉,截至13日晚19点,全市平均降水2.4毫米,地区最大降水量4.8毫米。降水预计将于今日结束,未来两天潍坊将遭遇持续性大风和强降温天气。据了解,今年潍坊头场雪,较去年冬天"迟到"了42天,此次降水未经人为干预,属于天然降水。

The voluminous rain and snow that fell on the 13th have made townspeople pleasantly surprised. Though since the cloud layer was low and thin, anti-aircraft artillery could be launched to reach the cloud layer. The artificial inducement of the rain couldn't be implemented on schedule.

Zhang Xueshan of the office of artificially influencing the weather in Weishang, Shandong province explained that suitable weather conditions are required for inducing rain artificially. Adequate water resourced should exist in the clouds in the sky as well as appropriate rain force conditions. Only if these two basic conditions are filled, various kinds of rain inducing equipment could be transmitted inside the cloud level as a catalyst, producing the desired effect. This time, the air during the precipitation process was so severely cold, and the cloud thickness level didn't 'reach the standards'. Launching anti-aircraft artillery and rockets requires an angle of 45 degrees, as well as a cloud layer at an altitude of at least 3000 meters, but this time, with the course of cold air, the highest cloud level is only at 2000 meters, not reaching the favorable conditions for putting the man-induced precipitation into effect.

Zheng Xuesheng told reporters that the launching course cannot be realized, as anti-aircraft artillery in rockets cannot reach the inside of the cloud layer, the catalyst cannot have an effect, and might affect the safety of the inhabitants on the ground.

Staff members of the office for artificially influencing weather in Weishang have already prepared for artificial rain inducement two months ago, but tardily cannot put it into effect. In the course of the cold air communication this time, workers are  constantly paying close attention to the weather situation since the dawn of the 13th, but the cloud layer conditions are completely unsatisfactory, the "lending water project" ultimately must be renounced.

Meteorologists explain, in order to indeed drop the sky's water to the ground, and not allow clouds to move out in vain, man-induced precipitation exists. Its can be achieved by two methods: "Inside the sky" and "ground surface operation". "In the sky" operation is using airplanes as a disseminating catalyst, "ground surface" operation is utilizing anti-aircraft weapons and rackets, launching them from the ground. Still, this doesn't mean that precipitation can be increased by as much as we want. Statistics show that using the man-made catalyst technology correctly can at most exploit 20% of the precipitation in the clouds.

According to what is understood, the principles of artificially induced rain can be summarized by these describing words: "Mechanism trigger". Even with the foundation of fully studying natural precipitation, man operation only triggers the natural rain mechanism. Rain can exist only if there are clouds, though not all clouds have a precipitation capacity. Only clouds with precipitation potential and the possibility of being utilized could be targeted by the rain catalyst.

On the dawn of the 13th, Shandong's Weifang city welcomes the first snow fall this winter. Reporters from Shandong's Weifang city's Weather Bureau has learnt, that by 19pm, December 13th, the mean precipitation in the entire city is 2.4 mm, highest precipitation in the district are of 4.8 mm. According to what is understood, the first snow fall in Weifang this year is late by 42 days compared to the winter last year. The precipitation this time has not been intervened by man and is natural precipitation.


[1] 人工增雨 réngōng zēng yǔ - 'Man made rain increase', artificial rain inducing; Methods to induce precipitation when rain clouds appear, as explained in this article.

[2] 潍坊市 wéifāng shì - Weifang city, a prefecture-level city in Shandong province.

[3] 催化剂 cuīhuàjì - Catalyst, inducing factors

[4] 气象 qìxiàng - Meterology



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