Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New evaporation model for water management

25.04.2002


"Formulas from 1948 were being used."

Monthly evaporation models, important for water management, can be improved by studying the dispersion of rain for each month. This is one of the conclusions in the research project of Marieke de Groen. She will defend her thesis on Monday the 29th of April. De Groen: “The subject was neglected for a long time. The monthly models contained formulas from 1948.”

Our main source of food – the agriculture sector – is very dependant on the weather. To determine whether it is wiser to build a dam, irrigate, or make better use of rainwater, monthly models are made. Evaporation plays an important part in these models. De Groen: “If you have 100 mm of rainfall in one month, it could al have fallen on one day, or maybe during 10 days. This is quite important for plants; after all, you don’t water your own plants only once a month.”



In her research, De Groen made a distinction between transpiration and interception. Transpiration is when water is absorbed by the plant through the roots and then evaporates through the leaves. Interception is when part of the rain-water doesn’t reach the ground, but lands on plant leaves and evaporates from there. “Transpiration causes plants to grow, interception doesn’t. That is why the distinction is important,” says De Groen. “This is also important in climate models. The classical models fall short on two points: they don’t take the dispersion of the rainfall over the month into account and they don’t deal with the difference between transpiration and interception.”

De Groen worked at the international hydraulics institute IHE in Delft, which does research in Zimbabwe. During her research period in Zimbabwe, she realised that the occurrence of ‘rain days’ takes place along the lines of the so-called Markov-theory. This means that the probability for rain on a certain day is only dependant on the amount of rain the day before. The theory helped De Groen to create simple monthly models for transpiration and interception. “The classical models simplistically assume that all the rain fell at the beginning of the month and they drastically simplify the relationship between the amount of water in the ground and the amount used by plants,” says De Groen, “I will show that you can make better models by using different assumptions, and they apply world-wide.”

The method developed by De Groen is especially valuable for water managers and hydrologists that depend on a limited amount of data in a limited time frame to be able to make strategic management decisions.



Maarten van der Sanden | alphagalileo
Further information:
http://www.tudelft.nl

More articles from Agricultural and Forestry Science:

nachricht Plasma-zapping process could yield trans fat-free soybean oil product
02.12.2016 | Purdue University

nachricht New findings about the deformed wing virus, a major factor in honey bee colony mortality
11.11.2016 | Veterinärmedizinische Universität Wien

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>