What Are Cirrostratus Clouds?

Cirrus clouds belong to the Gaoyun tribe. It sometimes occurs at the highest altitude where clouds can be formed, and the cloud base is generally between 4500 and 10,000 meters. It is composed of fine ice crystals at high altitudes, and the ice crystals are relatively sparse, so the clouds are thin and have good light transmission, the color is white, and the ice crystals are bright. Cirrus clouds are classified into four categories: Mao Cirrus Clouds, Hook Cirrus Clouds, Pseudo Cirrus Clouds, and Dense Cirrus Clouds according to their characteristics such as shape and structure.

Scientific name in Chinese: Cirrus

Latin name: Cirrus

International abbreviation: Ci

The formed cirrus clouds will also take on various forms due to the falling ice crystals passing through different air layers such as temperature, humidity, and wind. Scattered individuals often appear in a variety of forms, such as strands, ponytails, feathers, hooks, clusters, and flakes.

Cirrus clouds form for a variety of reasons, or because of high-altitude convection, often with the shape of a cumulus cloud; or

According to the shape and structure characteristics, cirrus clouds can be divided into

Study on the Distribution and Physical Properties of Cirrus Clouds

Cirrus clouds play an important role in atmospheric radiation. Their horizontal distribution affects the radiation field of the earth-gas system, and the information in the vertical direction is also very important for climate feedback. Preliminary observations of the horizontal distribution, optical characteristics, and microphysical properties of cirrus clouds are made using artificial observations, micropulse lidar, and millimeter-wave cloud survey radar data. (1) Using the cloud-like timing data from 756 ground-based meteorological basic reference stations in China since the establishment of the station to December 2010, statistical analysis of the horizontal distribution and seasonal variation of cirrus clouds. The results show that the annual frequency of dense cirrus clouds is much higher than that of the other three types of cirrus clouds, which are basically characterized by "lower south and higher north". Low-value centers are located in the southeastern region of Sichuan, with a frequency of less than 10%. The appearance frequency of cirrus clouds has obvious seasonal changes. Generally, the frequency continues to increase from winter to summer, and the frequency decreases from summer to autumn. (2) Micropulses in Beijing from November 2011 to May 2012 are used. The lidar data statistically analyzed the height, thickness and optical thickness of the cirrus cloud base. The results show that the height of the cirrus cloud base is mainly distributed between 5-10km, and the average altitude is 7.04 ± 1.10km. As the height of the cloud base increases, the frequency of cirrus clouds gradually decreases; the thickness of cirrus clouds is mainly distributed at 0.3 Between 1.5km and 1.5km, the average is 0.73 ± 0.25km; the cirrus cloud base height and thickness have a negative correlation; the cirrus cloud's optical thickness value is less than 0.14, and the optical thickness has a positive correlation with the thickness. (3) The algorithm based on the micropulse lidar and millimeter-wave cloud radar to inverse the microphysical properties of cirrus is studied.The algorithm uses the extinction coefficient and The cirrus echo signal intensity values measured by millimeter-wave radar together invert the cirrus' IWC (Ice Water Content, ice water content) and Dge (General Effective Size, particle effective size). Through the analysis of a cirrus cloud process in Shouxian, it is concluded that the ice water content of cirrus clouds is distributed at 10-3 10-1gm-3 and the effective size distribution of ice grains is 1 200m, which is consistent with empirical values and the changes are consistent The evolution of cirrus clouds illustrates the effectiveness of the method. It provides a feasible method for remote sensing of ground-based cirrus microphysical characteristics, and satellite data can be used to obtain global cirrus microphysical characteristics. ^[4]

Cirrus clouds have dual effects on Earth's radiation

The first is the scattering of solar short-wave radiation, which reduces the solar radiation reaching the surface and thus has a cooling effect on the surface; the second is that cirrus clouds have a greenhouse effect, absorbing long-wave radiation and heating (Zer efo set al., 20 03). F ua nd Liou (19 93) studies show that thin cirrus clouds cause positive radiative forcing at the top of the atmosphere, while thicker cirrus clouds exhibit a cooling effect. The fourth assessment report of the IP CC pointed out that there is still great uncertainty about the role of cirrus clouds in radiative forcing and climate change (I PCC, 2007). Cirrus clouds play an important role in the earth-atmosphere radiation balance, and its radiative forcing effect is an urgent problem to be solved in current global climate change research. ^[5]