A team of scientists from the Indian Institute of Sciences (IISc) has developed a new device that they said could measure the evaporation rate of a local area in a couple of minutes.
“The device is a more efficient and economical way to measure evaporation compared to existing methods,” Bengaluru-based IISc said in a statement on Friday.
“Our method allows you to get a much more realistic measure of transpiration from plants and evaporation from soils,” says Jaywant H Arakeri, professor in the Department of Mechanical Engineering at IISc and lead author of the study published recently in the Journal of Hydrology. . .
Evaporation is the process by which water changes from a liquid to a gaseous state.
In addition to being an integral process in the water cycle, evaporation also plays an important role in regulating water loss in plants through a process called transpiration.
Being able to measure the evaporation rate is useful for farmers to measure the water requirements for their fields and at weather stations to characterize local atmospheric conditions.
It is also widely used by botanists to study the dynamics underlying the transpiration of plants.
Currently, tray evaporimeters are the most widely used devices to measure evaporation rates.
They look like large saucepans filled with water.
The change in water level during a day gives the evaporation rate of that area for that day.
The disadvantages (of the existing methods) are that the evaporation rates are for a full day and over a large area (one square meter).
And an open ground is needed to place the device.
But we have a simple method to directly measure evaporation from a small surface on the order of a couple of centimeters, and over a short period of time, Arakeri explains.
The proposed device consists of a filter paper connected to a capillary tube that carries the water from a reservoir to the filter paper, moistening it and thus imitating a surface of water that evaporates.
By measuring the distance traveled by the lower meniscus in the capillary tube for a couple of minutes, the evaporation rate is estimated.
The innovation lies in being able to measure the very small amount (about a microliter) of water that is lost by evaporation from the surface in one minute, according to IISc.
Since the evaporation rate is affected by a number of factors such as temperature, wind speed, and humidity, this device could display the evaporation rate within a specific environment.
“It gives you an idea of the evaporation rate even from a small leaf. For example, if this device is kept close to a rice plant, we could get a better measure of the rate of evaporation that a particular leaf of that plant might be experiencing, ”explains Arakeri.
The device would be useful for scientists studying the physiological process of transpiration in plants because of its ability to measure the rate of evaporation in small areas for short periods of time, IISc said.
Stomatal responses can now also be addressed, in a better and more controlled way, using this device, according to the statement.
The authors also suggest that it could be used in the oceans to study changing evaporation patterns in the open ocean and at meteorological stations to estimate evaporation rates in the atmosphere, an important parameter that is currently not measured.
The next step is to make the device commercially available.
“We are looking for companies interested in adopting it and turning it into a product. In the meantime, we have been doing some experiments in the polyhouse (a kind of greenhouse that is used for growing in a controlled environment), and we also want to test it in the field, ”said Arakeri.