July 17, 2020


Ecosystem water stress and water resource management

With Trishna’s temperature measurements, we will be able to monitor plants’ water stress all over the globe, because it can be deduced from their surface temperature. A high temperature indicates that a plant is not transpiring and therefore suffering from water stress. Acquiring measurements every three days at a resolution of 57 metres, Trishna will deliver finely detailed data on the water status of crops and forests to enable land planners to adjust practices accordingly. For example, optimizing irrigation would help the farming sector—which today accounts for 70% of all global water consumption—to make significant water savings. Applying the right cultural practices at the right times in crop growth cycles could improve yields, vital in many countries like India, where the population already exceeds one billion.
By gauging evapotranspiration, Trishna will also indirectly reveal biogeochemical transfers between the compartments of the Earth system: water transports chemical pollutants which then filter down into the soil or escape into the air when it evaporates. Closer knowledge of these exchanges will inform land planning to avert polluting soils and thus improve water quality.

Hydrology of coastal strips and land surfaces

The sea-surface temperatures that Trishna will obtain in coastal zones are a good indicator of gas exchanges between the sea and atmosphere. Whether certain gases like carbon dioxide (CO2) are dissolved or rather released into the atmosphere depends not only on this surface temperature but also on biological activity. Trishna’s data will enable scientists to assess the status of marine ecosystems, i.e., fish stocks, the risk of algal blooms and the quality of sea water and water running into it from land surfaces. For example, in river deltas or near nuclear power stations, it will be possible to observe how thermal plumes mix and to track how they evolve. Further inland, monitoring of rivers, lakes and other water bodies is just as necessary to ensure effective management of water resources and good water quality.

Urban heat islands

In urban areas, land-use planning and human activities generate microclimates that can affect the quality of life and health of city dwellers. With populations increasingly moving to cities and rising summer temperatures, such heat islands are likely to get worse. Trishna data will help to better gauge the effect of greening urban areas and to make the right construction choices (architecture, orientation and materials, roofing, roads and pavements, etc.).


At high latitudes and elevations, surface temperature data will improve understanding into how climate change is affecting snow, polar ice caps, glaciers and permafrost. In high mountain areas, monitoring the water cycle by measuring glaciers, snow pack and lakes will enable better management of the basins their catchment areas. In India, where a significant portion of the nation’s available water comes from the Himalayas, such measurements will prove very valuable, as along with precipitation, the spatial and latitudinal distribution of temperature is a key driver in the hydrology of mountain drainage basins.


The energy budget of clouds is a key component of Earth’s overall radiation budget. Trishna’s temperature measurements will thus help us to refine our knowledge of ongoing climate change.

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