Measuring Soil Moisture for Global Maps
A NASA satellite called the Soil Moisture Active and Passive (SMAP) is scheduled to launch in 2014. Its mission will be to gather soil moisture data from above, eventually leading to global maps. In support of this project, University of Michigan engineering professors Mahta Moghaddam and Mingyan Liu are installing networks of wireless sensors on the ground in several test spots. The data from the sensors will be used to validate the satellite data - to help ensure that the orbiting instrument is giving accurate readings. "Root zone soil moisture is one of the most important pieces of information for understanding how ecosystems function, and how the water, energy, and carbon cycles are regulated around the globe," says Moghaddam.
Transcript
00:00:02 soil moisture is one of the most important parameters in um Global ecosystem studies it determines weather pattern so it's one of the most important things that the scientists are interested in when they study global climate change Madam and Ming yanlu are two professors in the University of Michigan's Department of electrical engineering and computer
00:00:24 science this summer with help from graduate students they expanded their lab into the garden the goal of the project is to set up a network of Institue soil moisture sensors the engineers are working on a NASA sponsored project to accurately measure soil moisture can you help me with this only two the idea is to uh come up with smart techniques for validating what we
00:00:50 derive from satellite data let's go to the next one so if you have a satellite and its way up there and it measures this whole area as just one number it's very hard to for us to validate that number uh unless we have several sensors on the ground I use I we use a screw here soil moisture it can change very fast from place to place and as a function of time for example today we
00:01:12 had drain so as soon as it drains of course the the very dry ground gets wet naturally we're here under the tree for a reason because it doesn't get wet so quickly right so you could tell within a distance of just a few meters soil moisture could change pretty drastically so if you have a satellite and its way up there and it measures this whole area just one number it's very hard to for us
00:01:34 to validate that number uh unless we have several sensors on the ground to somehow make the correspondence between what we measure on the ground and what the satellite [Music] measures so that's the whole purpose of the project and if you want to deploy the sensors in an extensive way we can't have sensors that are wired to our
00:01:56 measurement station right we need to have wireless sensors and that that's where manan's work comes into the picture because she's an expert in sensor networks wireless sensor networks so the basic idea is um as you have seen today here is um uh each location has consist of three underground soy moisture probes and they are being actuated controlled by a uh Wireless
00:02:20 ground module so this module actuates the sensors collects the data and wirelessly transmit the data back to a uh collector base station from what we retrieve on the ground which we call the truth because we actually measured it on the ground we adjust the satellite measurements we validate them so that uh later on we could expand this adjustment to everywhere else on the globe the
00:02:43 reason I'm really interested in soil moisture and problems having to do with water in general is that water is a very scarce natural resource as the population of the Earth increases water is going to become uh more and more scarce per person because there is only so much fresh water available and we all depend on it to live right so being able to understand how water gets distributed
00:03:05 in the Earth how it cycles and how we can best utilize it uh is going to be a huge issue uh in the coming years for for everyone in the [Music] world