When NASA blasts off to space, we assume it’s on a mission to explore where no man has gone before. But these days, the same sort of technology that enables us to explore new worlds is being used to look back at planet Earth. Specifically, the soil just beneath our feet. Turns out, some of life’s most important processes begin and end in the dirt.
Not just the stuff you track onto the carpet, dirt or soil, is the lifeblood of the planet; it’s the bridge that connects the inner workings of our planet to the atmosphere that surrounds it. And amazingly enough, you can find out quite a lot from measuring soil moistness. From drought predictions and flood warnings, to determining crop yields and climate changes, the benefits of testing the ground just inches beneath our feet are plentiful.
But this isn’t some new revelation discovered by men in lab coats. Farmers have always known this, and they’ve continually perfected their methods of testing. But as the world gets smaller and technology flies higher, what better way to keep track of the health of our land as a whole than with a more global perspective. And NASA has the rocket science to get the job done.
With their Soil Moisture Active Passive (SMAP) observatory – that uses both radar and radiometer measurements – NASA will create global maps of soil moisture that will provide valuable data for farmers and weather forecasters alike.
Active, because the satellite’s radar actively sends and receives radio waves indicating the moisture level of the soil. “Using an advanced radar and radiometer, the satellite peers beneath clouds, vegetation and other surface features to monitor water and energy fluxes.”
Passive, because the radiometer detects radio waves that are emitted by the ground from the same small area, sensing ground temperature. Together, the two instruments will make complete soil moisture maps of the earth, from pole to pole, every 2-3 days.
This means more accurate drought warnings, flood predictions and weather forecasting. Imagine the data being available real-time to determine crop yields, water supply, hydrology or climate change impacts.
Yes, soil moisture: it’s just a couple of inches below the surface and just a fraction of all the water on the planet, but it has an affect on every living thing on land. In fact, soil moisture is a major player in the Earth’s water, carbon and energy cycles.
We know that when it rains (or snows), water falls from the sky onto the land and then rises from the land back to the sky when it heats up and evaporates. But water is not the only thing that rises.
Evaporation gets rid of nearly half of the solar energy that reaches land, keeping our planet’s temperature comfortable. It’s called the energy cycle. Soil moisture determines how Earth heats up and cools down – which, in turn, drives weather.
If moisture is in the air due to soil moisture evaporation, low pressure systems will condense the moisture and precipitation will occur. If the soil is very dry, there will be less available moisture in the air and it is less likely for precipitation to occur if a low pressure system moves in.
Soil moisture is important for forecasting temperature too. As the temperature rises the evaporation rate of soil moisture increases. The increased soil moisture evaporation helps cool the ground.
Also rising from the soil is CO2. In fact, the amount of CO2 emissions from soil is ten times greater than that of human fossil fuel emissions. Called soil respiration or soil carbon flux, it is basically the by-product of bacteria and microorganisms after consuming organic materials in the soil.
But never fear: while soil respiration is a major contributor of greenhouse gasses, soil acts as a reservoir, or sink, for CO2 by a process called carbon sequestration. Not only does soil carbon sequestration provide a net sink for atmospheric concentrations of CO2 but it can increase crop yields, minimize erosion, and save in fuel costs associated with farming. Nature always has a way of healing itself.
During the Dust Bowl, Franklin D. Roosevelt said: ‘A nation that destroys its soils destroys itself.” Keeping the soil healthy and balanced is good for the earth and good for the living things on it. What NASA hopes to do is keep track of it all: the healthy land, the not-so-healthy land, the dry land, the frozen land.
Soil changes over time, and as it does, SMAP will be there to collects the data. And that data will be used to create models. And models will be used to make predictions about not only catastrophic events, like floods and droughts, but more importantly, to help farmers make sound choices regarding their soil.
The USDA’s National Water and Climate Center has already started a pilot program for a nationwide soil moisture monitoring system. Data from NASA’s SMAP observatory, along with microwave and thermal infrared observations from the NOAA (National Oceanic and Atmospheric Administration), plus the University of Arizona’s Cosmic Ray-Soil Moisture Observing System and the Texas A&M North American Soil Moisture Database will all be used together to create a National Soil Moisture Network.
The program hopes to provide farmers and land owners access to real-time data from a home computer, related to their specific location.