What are weather radar and weather satellite?

Meteorological radar belongs to active microwave atmospheric remote sensing equipment, which is specially used for atmospheric detection. Meteorological radar is one of the main detection tools for early warning and forecasting small and medium-scale weather. Meteorological satellite is an artificial earth satellite for meteorological observation of the earth and its atmosphere from space. Meteorological satellites have the advantages of wide observation range, many observation times, fast observation time limit and high observation data quality. Meteorological satellite is a kind of artificial earth satellite, which specializes in meteorological observation of the earth and its atmosphere from space.

Can weather radar really quantitatively estimate precipitation?

In the weather information released by the Meteorological Observatory, we can often hear the forecast of precipitation, such as "The precipitation in central and northern Chengdu will exceed 100 mm in the next two days", "It is predicted that there will be a rainstorm in Nanjing, and the rainfall will reach about 130 mm", and so on. Most of them are calculated by computer with numerical weather forecast model.

Meteorologists can also use "weather radar" to quantitatively estimate rainfall. The electromagnetic wave emitted by weather radar will scatter when it meets raindrops, ice crystals and snowflakes in the air, and the returned electromagnetic wave will be received by radar antenna and displayed on the screen. Meteorologists can understand the intensity, distribution and evolution of precipitation in the atmosphere according to the echo images.

On the radar screen, only the intensity, distribution, movement and evolution of radar echo can be seen. How do meteorologists estimate precipitation? Generally speaking, radar echo intensity and precipitation intensity have the same probability distribution. The Meteorological Observatory will collect and count the raindrop spectra of different regions, different precipitation types and different precipitation intensities, and then find out the relationship between the echo intensities of different types of precipitation and their corresponding precipitation intensities, so as to obtain a set of empirical formulas to quantitatively estimate precipitation.

In recent years, the technology of weather radar to estimate precipitation has been constantly updated. Moreover, the radar set on the ground will form a network, and the radar with satellite as the carrier can realize large-scale precipitation observation, which can make up for the shortage of single-point observation.

Doppler weather radar

Meteorological satellites can actually predict crop yields.

The weather forecast affects everyone's life. In particular, it has an important practical effect on crop harvest, and crop growth can also be predicted by meteorological satellites.

1September 1988, China launched its first meteorological satellite, Fengyun-1. Later, China successfully launched a number of polar-orbiting meteorological satellites and a number of stationary meteorological satellites-"Fengyun-2". On May 7, 2008, China launched Fengyun-3 meteorological satellite with more advanced functions and technology. On September 25th, 20 17, Fengyun-4 meteorological satellite was officially put into use.

As early as the early 1980s, scientists at home and abroad began to use the data obtained from polar-orbiting meteorological satellites to dynamically monitor crop growth.

Agricultural meteorologists can judge the growth status of crops, calculate the index and predict the yield per unit area of crops by using mathematical statistical models according to the ground data collected by satellite sensors.

Meteorological satellites can not only monitor weather and crops, but also detect forest and grassland fires, analyze the activities of fish schools and monitor sea fog, sea ice and environmental pollution. It can be seen that meteorological satellites are really omnipotent. In fact, satellite technology has been widely used in many fields and achieved remarkable results.