What’s up? Learn about weather changes

Know the weather by looking at clouds

Characteristics and classification of clouds

Clouds are water droplets condensed from water vapor in the atmosphere, supercooled water droplets, ice crystals or a mixture of them Visible suspension.

The formation, appearance characteristics, amount, distribution and evolution of clouds not only reflect the movement, stability and water vapor conditions of the atmosphere at that time, but are also one of the important features that predict future weather changes. Correct observation and analysis of cloud changes is an important factor in understanding the physical conditions of the atmosphere and grasping the laws of weather changes.

The formation and change of clouds are very complex. Like anything, they contain their own special contradictions, resulting in their colorful appearance and ever-changing characteristics. Only by mastering these characteristics of clouds can we correctly identify clouds and continuously improve the level of cloud observation.

The appearance characteristics of clouds are ever-changing, and the causes of their formation are different, but they have their own unique characteristics. Usually based on their unique characteristics and combined with actual needs, clouds are divided into three families: low, medium and high according to the height of the cloud bottom, and then divided into ten genera and several categories according to the cloud's appearance characteristics, structure and nucleation origin.

Cloud Family Clouds belong to the cloud category

Low clouds, cumulus, light cumulus, dense cumulus, broken cumulus, cumulonimbus, bare cumulonimbus, stratocumulus, light-transmitting layer, cumulus-shielding layer Cumuluscumulus stratocumulus fortress stratocumulus lenticular stratocumulus stratocumulus stratus nimbus nimbus stratus stratus nimbus nimbus stratus mid-level cloud altostratus light-transmitting altocumulus blocking light altocumulus altocumulus flocculent altocumulus cumulus altocumulus fortress altocumulus lenticular altocumulus blocking light altocumulus transmitting light altocumulus high cloud cirrus cirrus dense cirrus pseudo cirrus hook cirrus cirrostratus cirrostratus thin curtain cirrocumulus cirrocumulus cirrocumulus

Low clouds are mostly composed of water droplets. Thick or vertically developed low clouds are composed of a mixture of water droplets, supercooled water droplets, and ice crystals. The cloud base height is generally below 2,500 meters, but it varies with seasons, weather conditions and different geographical latitudes. Most low clouds may produce precipitation. Nimbostratus clouds often have continuous precipitation, and cumulonimbus clouds often have intermittent precipitation, sometimes with heavy precipitation.

Cumulus clouds

Cumulus clouds are distinct individuals, with a flat bottom and a convex top. The clouds are mostly disconnected; clouds formed by air convection and water vapor condensation.

Cumulonimbus

The clouds are dense and thick, and the cloud body is huge, much like a towering mountain. The top has begun to freeze, it is white, the outline is blurred, and some have a fiber-like structure. . The bottom is very dark, often with drooping rain streamers or broken rain clouds.

Cumulonimbus clouds are mostly composed of water droplets, supercooled water droplets, ice crystals, snowflakes, and sometimes also contain particles and hail. There are strong rising and downdraft areas within the cloud. Rising and downdrafts with speeds of tens of meters per second can be observed, and undulating cloud bases often appear.

Cumulonimbus clouds are the peak stage of convection development. Mature cumulonimbus clouds often produce strong bursts of precipitation, which can be accompanied by strong winds, thunder and lightning, sometimes hail, and occasionally tornadoes.

Stratocumulus

Clouds are generally larger and vary greatly in thickness and shape, some in strips, some in sheets, and some in groups. Often off-white or gray, the structure is relatively loose. Thin clouds can tell the position of the sun, while thick clouds are darker. Cloud patches are often arranged in rows or waves.

The thickness of stratocumulus clouds generally ranges from a few hundred meters to two thousand meters. It is mostly composed of water droplets with a diameter of 5-40 microns. Cumulonimbus clouds that appear in winter may also be composed of ice crystals or snow flakes.

In most cases, stratocumulus clouds are formed due to the condensation of water vapor due to the wavy movement and turbulent mixing of air. Sometimes it is formed by intense radiation cooling. Generally, it means that the weather is relatively stable, but if the stratocumulus clouds gradually thicken or even merge into layers, it means that the weather will change. Low, thick stratocumulus clouds tend to produce precipitation.

Stratus

The clouds are uniformly layered, gray and resemble fog, and the cloud base is very low but does not touch the ground.

Stratus clouds are generally composed of water droplets or supercooled water droplets with a diameter of 5-30 microns. The thickness is generally 400-500 meters.

Stratus clouds are formed when water vapor condenses or fog rises due to strong radiation cooling or turbulent mixing at night when the air layer is stable. Stratus clouds often dissipate after sunrise as the temperature rises and the stable layer is destroyed. Sometimes stratus clouds can also produce drizzle or light snow.

Nimbostratus

Nimbostratus clouds are low and amorphous. The clouds are evenly layered and can completely block the sun and moon. They are dark gray or off-white, and are often accompanied by broken clouds at the base. Rain clouds. Clouds are widely distributed horizontally, often covering the entire sky. The thickness of the cloud layer reaches 4000-5000 meters.

The lower part of nimbostratus clouds is generally composed of water droplets or supercooled water droplets. The upper parts of nimbostratus clouds that appear in the north are often composed of ice or snow crystals.

Nimbostratus clouds mostly appear in warm front cloud systems (sometimes appearing in other weather systems). They are formed by the entire layer of moist air systems sliding up and cooling adiabatically. It often causes continuous precipitation for a long period of time. The farmer's proverb "The gray cloth hangs in the sky and the rain is continuous" refers to the precipitation status of nimbostratus clouds.

Medium clouds

Medium clouds are mostly composed of water droplets, supercooled water droplets, ice crystals or a mixture of them. Some altocumulus clouds can also be composed of a single water droplet. Cloud base height is usually between 2500-5000 meters.

Altostratus clouds often produce precipitation, while thin altocumulus clouds generally produce no precipitation.

Altostratus clouds

The clouds are uniformly distributed, off-white or gray, and the cloud base often has a strip structure. They often appear in frontal cloud systems and often cover the entire sky. Altostratus clouds are generally composed of water droplets with a diameter of 5-20 microns, supercooled water droplets mixed with ice crystals and snow crystals.

Altocumulus

The clouds are smaller and have clear outlines. They are very different in thickness and layer. Thin clouds are white, and the outlines of the sun and the moon can be seen. Thick clouds are It turns into dark gray, and the outline of the sun and moon cannot be distinguished clearly. They often form oblate, tile-like fish scales or water-wave-like dense cloud strips.

Altocumulus clouds are composed of water droplets or a mixture of water droplets and ice crystals. Sunlight and moonlight pass through thin altocumulus clouds and often form a halo or bloom of blue inside and red outside due to diffraction.

The formation of altocumulus clouds is similar to that of stratocumulus clouds. Thin altocumulus clouds are stable and rarely change, and generally indicate sunny days. There is a saying among the people that "clouds with tiles are harmful to the sun" and "carp spots in the sky do not need to be turned over when the sun is shining". If the thick altocumulus clouds continue to thicken and merge into layers, it means that the weather will change and even precipitation will occur.

High clouds

High clouds are all composed of tiny ice crystals. Cloud base height is usually above 5,000 meters. High clouds generally do not produce precipitation. In winter, cirrostratus and dense cirrus clouds in the north occasionally snow, and snow streamers can sometimes be seen.

Cirrus clouds

Clouds have a fibrous structure, often white, without shadows, with a hair-like luster, and are mostly in the form of strips, sheets, feathers, or hooks. Shape, lump, etc. Cirrus clouds are composed of ice crystals.

Cirrostratus clouds

The clouds are uniformly layered, transparent or milky white, with clear outlines of the sun and moon through the clouds, shadows on ground objects, and often halos. Cirrostratus clouds thicken and reduce, and the system develops, which often indicates that weather systems will affect the measuring station. Therefore, there are folk sayings such as "midnight rain in the solar halo and wind at noon in the lunar halo". However, if there is no obvious development, or even the cloud cover decreases, there will be no significant change in the weather in the future.

Cirrocumulus clouds

The clouds are very small, in the shape of thin white flakes, often arranged in rows and groups, much like the breeze blowing on the water. into small ripples. Cirrocumulus clouds are usually formed by fluctuations in high-altitude stratification instability. If the sky is dominated by cirrocumulus clouds and is related to and develops systematically with cirrocumulus clouds, it generally indicates that a weather system will affect the measuring station, with frequent rainy and windy weather. The farmer's proverb "the sky is like a fish's scale, even if it doesn't rain, it's like a phoenix" refers to this situation.