Preventive earth observation for the climate change

Nowadays, topics concerning the global climate and its necessary protection receive more and more attention in the international media. Especially in recent weeks, months and years, the importance of prevention has become clear, as in the case of the current raging forest fires in Spain, Italy or Greece, or past fires, such as those last year in the United States of America. Fires currently taking place around the world can be followed in near real time on the National Aeronautics and Space Agency NASA website (https://firms2.modaps.eosdis.nasa.gov/map/#d:2021-08-23..2021-08-24;l:country-outline;@0.0,0.0,3z). The majority of these fires could have been prevented or at least anticipated by preventive measures and thus better fought. 

First and foremost, it is important to distinguish between two types of forest fires: On the one hand, parts of the global forest areas are deliberately burned down in order to eventually use these areas as industrial areas. On the other hand, parts of the forest are set on fire by natural events, where humans are not the direct trigger of the fire, but only optimizes the conditions (for example by influencing the climate) in favor of a fire.

Fire prevention measures are consequently applied to the latter, recording factors such as wind direction and speed, relative humidity and temperature, type of vegetation and associated soil conditions, as well as the elevation of a terrain and the resulting general fire risk. All these data are collected with the help of satellites, in the European area the German company “Ororatech” is a representative of this technology.

Construction of the CubeSat

Ororatech uses innovative and versatile Cubesats (see Figure 1), which have 40% more payload volume compared to conventional CubeSat satellites. Due to constant technological progress in recent years, the size of this satellite has been limited to only 3000cm3 (30cmx10cmx10cm). Despite the size, such a nanosatellite contains a camera, an image processing processor and the necessary support electronics. CubeSats are built with commercially available components and are thus relatively inexpensive compared to the old large satellites, allowing for greater quantity of satellites deployed.

In addition to data from specially constructed nanosatellites, data sets from existing satellites are also used. Long-term complementary use of the instruments guarantees 600 km sun-synchronous orbits, up to seven orbital planes launched in several steps and several overflights per hour.

Implemented technologies

On board, among other already mentioned sensors, is a fundamentally important multispectral thermal infrared camera module (see Figure 2). It can detect both midwave and longwave infrared radiation, making it an ideal choice for detecting high-temperature events – forest fires.
In addition, a state-of-the-art GPU-accelerated on-board processing module is built into the satellite, which greatly reduces the data transmission time, allowing forest fires to be detected while still on board the CubeSat. Based on this, the delay in disseminating forest fire warnings can be reduced by several hours.

The impact of climate change on fire incidents

The general trend of significantly increasing temperatures for decades (see Figures 5 and 6) indicates a tendency of increasing risk for forest fires. Regions with low precipitation that already had dry vegetation or parched soils are only experiencing more and more risk of bursting into flames, while an increasingly number of humid areas are losing their humidity. This not only greatly increments the risk of devastating wildfires, but also throws the ecological system out of balance, and makes it more difficult to extinguish the fire.
Lavorel et al. (2007) further concluded that fires affect not only the fauna and vitality of a system, but also the climate itself. Fires and the resulting changes in vegetation have significant effects on the atmosphere, biochemical processes, and numerous other ecological control circuits. This then leads to a vicious circle, as it again optimizes the conditions of a fire incident.

Satellite remote sensing for home

Satellite remote sensing can also be carried out in near real time from home. Using the interactive online tool (https://apps.sentinel-hub.com/eo-browser/) of the European Space Agency ESA, data from more than 15 satellites can be viewed. Information on air pollution, flood hazards, ozone layer changes, glaciers, volcanoes and droughts, as well as forest fires, oceans and water bodies, can be accessed (see Figure 3).
After selecting the desired satellite(s) and intended data set, one only has to select any time period in the lower left corner before pressing the “Search” button and accessing the interactive map with the respective selected information. You will then be presented with a variety of different records, simply select the one you want by clicking on it and, if you wish, create a time-lapse recording of it using the camera icon in the right-hand bar (see Figure 4).
The website offers a number of options and settings, but most of them are self-explanatory.

Figure 4 shows an exemplary time-lapse representation based on the forest fires in the area of Greece and Turkey. As a time period the frame from 23.07.2021 to 23.08.2021 was examined, the data were measured by the satellite Sentinel 3SLSTR (Sea and Land Surface Temperature Radiometer). This measured both the temperature in said environment and the infrared radiation. This combination is ideally suited for the detection of forest fires.

Author: Carmen Engele (Aug. 2021)

Dieser Artikel ist auch verfügbar auf: German