Origin of hurricanes, harvesting and saving energy. Why else do we need data from space?

(ORDO NEWS) — SpaceX‘s Falcon 9 launch vehicle carrying the SWOT (Surface Water and Ocean Topography) satellite was launched today as part of a joint Franco-American mission.

The Canadian Space Agency (CSA) and the United Kingdom Space Agency (UKSA) are also participating. As indicated on the NASA website, the device will be launched into low Earth orbit at an altitude of 890 km.

The new satellite will make it possible to most accurately determine the level of the World Ocean, as well as to better understand the mechanisms of the water cycle in nature and improve the control of water resources on the planet.

Among several hundred scientific spacecraft operating in the Earth’s orbit, most of them are engaged in its remote sensing. Mankind launches satellites in order to study our planet as conveniently as possible from a height.

The first photographs of the Earth were taken by the Americans in 1946, when a V-2 rocket launched in the United States from the White Sands range entered a suborbital trajectory with an apogee of 105 km and took a series of photographs.

More than ten years remained before the launch of the first satellite, and a satellite image of the planet had already been taken.

Automatic spacecraft for remote sensing of the Earth (ERS) appeared later, in the 60s, and developed over the following years. Currently, Earth remote sensing data are used in many different sectors of the national economy.

Without data received from space, meteorologists, geologists, rescuers, farmers and many other specialists cannot fully work. How does it work?

Images and more

Earth remote sensing spacecraft are in constant operation and generate a huge amount of a wide variety of data. These are images in various ranges from visible to radio, radar survey data.

Depending on the tasks to be solved and the required data, satellites have different working orbits and payloads. For example, hydrometeorological devices of the Electro-L series are in geostationary orbit.

The speed of objects in this orbit is synchronized with the rotation of the Earth, and for an observer on Earth, these spacecraft are always above the same point.

This is very convenient for communication satellites or for devices such as Elektro-L, which receive images of the Earth from a long distance.

With the help of a multi-zone scanning device for hydrometeorological support (MSU-GS), every 30 minutes it takes pictures of the Earth in three visible and seven infrared spectral channels.

The height of the geostationary orbit is 35,786 km above sea level, so the satellite captures the entire globe, while obtaining images with a resolution of 1 km per pixel (in the infrared – 4 km per pixel).

In such images, meteorologists see the birth of hurricanes, snow cover on a planetary scale, large-scale changes in the atmosphere.

Why is it necessary to obtain images in the spectrum that we cannot see – from 700 to 12 thousand nm? They have a lot of applications, they allow you to see what the eye cannot make out in the visible spectrum.

For example, water absorbs waves in the near infrared, so this is useful for defining the boundary between land and water features that are not always visible in visible light.

Mid-infrared images can show wildfires or determine the amount of moisture in clouds, which is very important for meteorologists.

And there is also the thermal, or long-wave, infrared range, which includes wavelengths between 8 thousand and 12 thousand nm.

On images in this range, heat sources are clearly visible, you can determine how warm the soil is and when it is time to plant crops in a particular region.

And this is only one of the instruments of the Elektro-L spacecraft. But on board there is still a heliogeophysical instrumentation complex with seven sensors, including spectrometers and detectors of electrons and protons, meters of the solar constant, X-ray and ultraviolet radiation of the Sun, and even meters of the magnetic field vector.

Using the data obtained from the Elektro-L and its “brother” Arktika-M, scientists compile the most accurate weather maps – temperature, humidity, pressure and wind.

But this is not only a weather forecast for the inhabitants of the country, it is an opportunity to use energy more economically for space heating, more efficient road cleaning and much more.

And all this is only on one spacecraft. But there are still many satellites operating much closer to the Earth than the geostationary orbit.

With their help, images with a much higher resolution, up to several tens of centimeters per pixel, are obtained.

Naturally, the swath of scanning devices and cameras of such devices is also smaller; it does not see the entire planet, but shoots a small strip several kilometers wide.

Therefore, such spacecraft have to be constantly retargeted, set to capture the most interesting areas of the terrain and objects.

Time to process

As a result, it turns out that Earth remote sensing spacecraft constantly generate a huge amount of information. But if it is not processed and interpreted correctly, it will all remain dead weight.

And this is where scientists and specialists from various scientific institutions of the country, working with such data, come into play.

Their job is precisely to create new ways of processing data and applying them.

Using the obtained images, with the joint processing of data in different ranges, one can obtain information that simply cannot be seen without the help of processing.

For example, special processing makes it possible to study floods, although in the visible spectrum water-filled areas are not particularly visible.

In order to determine them, a synthesis of the near infrared and green channels is needed, because dirty water merges with brown earth in natural color reproduction.

Or how to distinguish between ice and snow to study the ice conditions, because for the eye all shades of white and light gray merge into one.

In this case, near infrared light is needed to highlight the difference between water vapor clouds, ice and snow, which are white in the visible range.

As a result, scientists create programs-services that end users need. Simply giving an agronomist a satellite image of his farm’s fields will not help in any way.

But a service that issues heat maps of field temperatures in different areas will already be very useful and will allow you to correctly distribute the timing of wheat planting, depending on where the ground warms up better, where the humidity is higher.

If on a scale of 1–2 hectares these data can be obtained manually, then on vast territories one cannot do without help from space.

And such scientific research, which is gradually becoming useful and convenient for end users, is constantly being conducted by services.

Maps of illegal deforestation, ice conditions on the Northern Sea Route, areas where there is not enough nitrogen fertilizers. All these data can be obtained using spacecraft for remote sensing of the Earth.

Even geological surveys, the search for minerals in the modern world begins with the study of satellite images.

It is on them that, according to indirect data, the changed color of the vegetation or the difference in temperature conditions, it is possible to assume the occurrence of minerals with a high degree of probability.

Separately, it should be said about the importance of satellite data for ecology. For example, with the help of radar images, specialists can detect even small oil pollution on the sea surface.

Identifying and quickly warning of a potential oil spill is the most effective pollution control strategy. And no one can do it better than spacecraft.

They can detect an oil slick, pinpoint its boundaries and monitor the spill until the accident is over and cleanup work is completed.

Spacecraft for remote sensing of the Earth are invisible, but such important assistants that allow increasing efficiency in a variety of seemingly unexpected industries.

Gather more crops, monitor the environment, prevent disasters and look for minerals. Remote sensing satellites have become a truly indispensable tool for thousands of specialists who can no longer imagine their work without cosmic “eyes and ears”.


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