The weather - a set of relatively short-term atmospheric phenomena - is difficult to predict due to the large number of factors affecting it, and the variability of their impact. The Earth's atmosphere is a complex dynamic system, therefore, to improve the accuracy of forecasting, it is necessary to take into account its state in different regions at every moment. For several decades now, meteorological satellites have been a necessary tool for conducting atmospheric research on a global scale.
Beginning of space weather observations
The satellite that showed the fundamental suitability of spacecraft for meteorological observations was the American TIROS-1, launched on April 1, 1960.
The satellite transmitted the first television image of our planet from space. Subsequently, on the basis of devices of this type, the global meteorological satellite of the same name was created.system.
The first meteorological satellite of the USSR, Cosmos-122, was launched on June 25, 1966. It had on board equipment for shooting in the optical and infrared ranges, made it possible to study the distribution of clouds, ice fields and snow cover, as well as measure the temperature characteristics of the atmosphere on the day and night sides of the Earth. Since 1967, the Meteor system began to function in the USSR, which formed the basis of subsequently developed meteorological systems for various purposes.
Satellite weather systems of different countries
Several series of satellites, such as Meteor-Nature, Meteor-2 and Meteor-3, as well as devices of the Resurs series, became the heirs of Meteor. Since the beginning of the 2000s, the creation of the Meteor-3M complex has continued. In addition, the number of meteorological satellites of Russia included two satellites of the Electro-L complex. With the first of them, which worked in orbit for 5 years and 8 months, the connection was lost in 2016, the second one continues to work. The launch of the third satellite of this series is planned.
In the USA, in addition to the TIROS system, spacecraft of the Nimbus, ESSA, NOAA, GOES series were developed and used. Several NOAA and GOES series units are currently in service.
European satellite weather systems are represented by two generations of Meteosat, MetOp, as well as the discontinued ERS and Envisat - one of the largest devices launched into low Earth orbit by the European Space Agency.
Japan ("Himawari"), China ("Fengyun"), India (INSAT-3DR) and some other countries have their own meteorological satellites.
Types of satellites
Spacecraft included in the meteorological complexes are divided into two types according to the parameters of the orbit and, accordingly, by purpose:
- Geostationary satellites. They are launched in the equatorial plane, in the direction of the Earth's rotation, to a height of 36,786 km above sea level. Their angular velocity corresponds to the rotational speed of the planet. With such orbital characteristics, satellites of this type are always above the same point, if you do not take into account the fluctuations and "drift" caused by errors in orbiting and gravitational anomalies. They constantly observe one area, which is about 42% of the earth's surface - a little less than a hemisphere. These satellites do not allow observing the regions of the highest latitudes and do not provide a detailed image, but they provide the possibility of continuous monitoring of the situation in large regions.
- Polar satellites. Vehicles of this type move in much lower orbits - from 850 to 1000 km, as a result of which they do not provide a wide coverage of the observed territory. However, their orbits necessarily pass over the poles of the Earth, and one satellite of this type is capable of “removing” the entire surface of the planet in narrow (about 2500 km) bands with good resolution in a certain number of orbits. With the simultaneous operation of two satellites located in sun-synchronous polar orbits, each region is surveyed frominterval of 6 hours.
General description and characteristics of meteorological satellites
A spacecraft designed for meteorological observations consists of two modules: a service module (satellite platform) and a payload carrier (instruments). The service compartment houses power equipment that provides power from solar panels mounted on it along with a radiator and propulsion system. A radio engineering complex equipped with several antennas and sensors for monitoring the heliophysical situation are connected to the working module.
The launch weight of such devices usually reaches several tons, the payload is from one to two tons. The record holder among meteorological satellites - the European Envisat - had a launch weight of over 8 tons, a useful one - more than 2 tons with dimensions of 10 × 2.5 × 5 m. With deployed panels, its width reached 26 meters. The dimensions of the American GOES-R are 6.1 × 5.6 × 3.9 m with almost 5200 kg of launch weight and 2860 kg of dry weight. The Russian Meteor-M No. 2 has a body diameter of 2.5 m, a length of 5 m, a width with deployed solar panels of 14 m. The payload of the satellite is about 1200 kg, the launch weight was slightly less than 2800 kg. Below is a photo of the meteorological satellite "Meteor-M" No. 2.
Scientific satellite equipment
As a rule, weather satellites carry two types of instruments as part of their equipment:
- Overview. With their help, television and photographic images of the surface of the land and oceans, clouds, snow and ice cover are obtained. Among these instruments there are at least two devices for multi-zone imaging in different spectral ranges (visible, microwave, infrared). They shoot at different resolutions. The satellites are also equipped with a radar surface scanning facility.
- Measuring. By means of instruments of this type, the satellite collects quantitative characteristics reflecting the state of the atmosphere, hydrosphere, and magnetosphere. Such characteristics include temperature, humidity, radiation situation, current parameters of the geomagnetic field, etc.
The meteorological satellite payload also includes an onboard data acquisition and transmission system.
Receiving and processing data on Earth
The satellite can operate both in the mode of storing information with subsequent transmission of a data packet to a ground-based receiving and processing complex, and conduct a direct direct transmission. The satellite data received by the ground complex are subjected to decoding, during which the information is linked by time and cartographic coordinates. Then data from different spacecraft are combined and further processed to create visually perceptible images.
The World Meteorological Organization adopted the concept of "open skies", declaring free access to meteorological information - unencryptedreal-time data from satellites. To do this, you must have the appropriate receiving equipment and software.
International Meteorological Observing System
Because there is only one geostationary orbit, its use requires coordination between space agencies and meteorological (as well as other interested) services of different countries. Yes, and when choosing low polar orbits at the present time, it is impossible to do without coordination. In addition, satellite monitoring of dangerous weather events (such as typhoons) makes it necessary to unite the efforts of hydrometeorological services and exchange relevant information, since the weather knows no state borders.
Harmonization of international issues relating to the application of space systems in weather forecasting is the responsibility of the Coordinating Group for Meteorological Satellites within WMO. The sharing of satellite weather systems began as early as the 1970s. Coordination in this area is especially important now. After all, the international constellation of meteorological satellites placed in geostationary orbit includes spacecraft from many countries: the United States, European countries, Russia, India, China, Japan, and South Korea.
Prospects for space technology in meteorology
Modern weather satellites are part of the global Earth remote sensing system and as such have serious development prospects.
Firstly, it is planned to expand their participation in monitoring natural hazards, natural disasters, dangerous phenomena, in forecasting long-term climate change. Secondly, meteorological satellites of the Earth, of course, should be increasingly used as tools for obtaining knowledge about processes in the atmosphere and hydrosphere, as well as about the state of the geomagnetic field, both applied and fundamental scientific value.
