World Meteorological Day 2017: Understanding Clouds

The World Meteorological Organization (WMO) said the theme for this year's World Meteorological Day (March 23) was chosen as "Understanding clouds".

In a message to member countries, Prof. Petteri Taalas, Secretary General of WMO, emphasized that “Understanding clouds” is an important basis for weather forecasting, simulating the impacts of future climate change and predicting water resources. Because clouds play a very important role in regulating climate, weather and the Earth’s energy balance. Clouds have contributed to regulating the water cycle and the entire climate system.

More than two thousand years ago, the philosopher Aristotle studied clouds and wrote a treatise explaining their role in the hydrological cycle. However, it was Luke Howard, an amateur meteorologist living in England, who first created a classification of clouds in the early 19th century.

Based on his extensive records of weather in the London area from 1801 to 1841, Howard identified three main genera, or categories, of clouds: cumulus, stratus, and cirrus. The identification, description, and naming of clouds remains crucial to the study of weather and climate.

From this classification, at the end of the 19th century, scientists created the International Cloud Atlas to serve the research of astronomical weather. This Atlas includes detailed instructions on cloud standards and many images of clouds and some other weather phenomena.

To mark World Meteorological Day this year, WMO is updating its Cloud Atlas. The 2017 edition will be available digitally online. It provides a comprehensive list of cloud types, with hundreds of images of cloud types such as roll clouds, contrails, and even wave-like clouds. It also contains important information on other meteorological phenomena such as rainbows, halos, snowdrifts, and hail.

According to Tuoi Tre