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Posts from the ‘Micrometeorology’ Category

Stop Hiding Behind a Shield

Get better air temperature accuracy with this new method

Accurate air temperature is crucial for microclimate monitoring

The accuracy of air temperature measurement in microclimate monitoring is crucial because the quality of so many other measurements depend on it. But accurate air temperature is more complicated than it looks, and higher accuracy costs money. Most people know if you expose an air temperature sensor to the sun, the resulting radiative heating will introduce large errors. So how can the economical ATMOS 41’s new, non-radiation-shielded air temperature sensor technology be more accurate than typical radiation-shielded sensors?

We performed a series of tests to see how the ATMOS 41’s air temperature measurement compared to other sensors, and the results were surprising, even to us. Learn the results of our experiments and the new science behind the extraordinary accuracy of the ATMOS 41’s breakthrough air temperature sensor technology.

In this brief 30-minute webinar, find out:

  • Why you should care about air temperature accuracy
  • Where errors in air temperature measurement originate
  • The first principles energy balance equation and why it matters
  • Results of experiments comparing shielded sensor accuracy against the ATMOS 41
  • The science behind the ATMOS 41 and why its unshielded measurement actually works

 

Register for the Live Event

Date: July 26, 2017 – 8:00 AM – 8:30 AM PDT

Where Will the Next Generation of Scientists Come From?

The Global Learning and Observations to Benefit the Environment (GLOBE) Program is an international science and education program that provides students and the public worldwide with the opportunity to participate in data collection and the scientific process.

GLOBE

GLOBE has a huge impact in schools around the world.

Its mission is to promote the teaching and learning of science, enhance community environmental literacy and stewardship, and provide research quality environmental observations.  The GLOBE program works closely with agencies such as NASA to do projects like validation of SMAP data and the Urban Heat Island/Surface Temperature Student Research Campaign.  The figure below shows the impact GLOBE is having in schools worldwide.

Dixon Butler, former GLOBE Chief Scientist, is excited about the recent African project GLOBE is now participating in called the TAHMO project.  He says, “Right now, in Kenya and Nigeria, GLOBE schools are putting in over 100 new  mini-weather stations to collect weather data, and all that usable data will flow into the GLOBE database.”

GLOBE

Participating in real science at a young age gets youth more ready to be logical, reasoning adults.

Why Use Kids to Collect Data?

Dixon says kids do a pretty good job taking research quality environmental measurements.  Working with agencies like NASA gets them excited about science, and participating in real science at a young age gets them more ready to be logical, reasoning adults.  He explains, “The 21st century requires a scientifically literate citizenry equipped to make well-reasoned choices about the complex and rapidly changing world. The path to acquiring this type of literacy goes beyond memorizing scientific facts and conducting previously documented laboratory experiments to acquiring scientific habits of mind through doing hands-on, observational science.”

Dixon says when GLOBE started, the plan was to have the kids measure temperature.  But one science teacher, Barry Rock, who had third grade students using Landsat images to do ozone damage observations, called the White House and said, “Kids can do a lot more than measure temperature.” He gave a presentation at the White House where he showed a video of two third grade girls looking at Landsat imagery. They were discussing their tree data, and at one point, one said to the other, ‘That’s in the visible. Let’s look at it in the false color infrared.’  At that point, Barry became the first chief scientist of GLOBE, and he helped set up the science and the protocols that got the program started.

GLOBE

GLOBE uses online and in-person training and protocols to be sure the students’ data is research quality.

Can GLOBE Data be Used by Scientists?

GLOBE uses online and in-person training and protocols to be sure the students’ data is research quality.  Dixon explains, “There was a concern that these data be credible, so the idea was to create an intellectual chain of custody where scientists would write the protocols in partnership with an educator so they would be written in an educationally appropriate way.  Then the teachers would be trained on those protocols. The whole purpose is to be sure scientists have confidence that the data being collected by GLOBE is useable in research.”

Today GLOBE puts out a Teacher’s’ Guide and the protocols have increased from 17 to 56.  The soil area went from just a temperature and moisture measurement to a full characterization.  Dixon says, “We’ve been trying to improve it ever since, and I think we’re getting pretty good at it.”  

GLOBE

GLOBE students were the only ones going around looking up at the sky doing visual categorization of clouds and counting contrails. It was just no longer being done, except by these students.

What About the Skeptics?

If you ask Dixon how he deals with skeptics of the data collected by the kids, he says, “I tell them to take a scientific approach.  Check out the data, and see if they’re good.  One year, a GLOBE investigator found a systematic error In U-tube maximum/minimum thermometers mounted vertically, which had been in use for over a century, that no one else found. The GLOBE data were good enough to look at and find the problem.  There are things the data are good for and things they’re not good for. Initially, we wanted these data to be used by scientists in the literature, and there have been close to a dozen papers, but I would argue that GLOBE hasn’t yet gotten to the critical mass of data that would make that easier.”

GLOBE did have enough cloud data, however, to be used in an important analysis of geostationary cloud data where the scientist compared GLOBE student data with satellite data Dixon adds, “GLOBE students were the only ones going around looking up at the sky doing visual categorization of clouds and counting contrails. It was just no longer being done, except by GlOBE students. Now GLOBE has developed the GLOBE Observer app that let’s everyone take and report cloud observations.”

GLOBE

Young minds need to experience the scientific approach of developing hypotheses, taking careful, reproducible measurements, and reasoning with data.

What’s the Future of GLOBE?

Dixon says GLOBE’s goal is to raise the next generation of intelligent constituents in the body politic. He says, “I thought about this a lot when I worked for the US Congress.  In addition to working with GLOBE, I now have a non-profit grant-making organization called YLACES with the objective of helping kids to learn science by doing science.  Young minds need to experience the scientific approach of developing hypotheses, taking careful, reproducible measurements, and reasoning with data. Inquiries should begin early and grow in quality and sophistication as learners progress in literacy, numeracy, and understanding scientific concepts. In addition to fostering critical thinking skills, active engagement in scientific research at an early age also builds skills in mathematics and communications. These kids will grow up knowing how to think scientifically. They’ll ask better questions, and they’ll be harder to fool.   I think that’s what the world needs, and I see the environment and science as the easiest path to get there.”

Learn more about GLOBE and its database here and about YLACES at www.ylaces.org.

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New Weather Station Technology in Africa-3

The Trans African Hydro and Meteorological Observatory (TAHMO) project expects to put 20,000 microenvironment monitors over Africa in order to understand the weather patterns which affect that continent, its water, and its agriculture. In the conclusion of our 3 part series, we  interview Dr. John Selker about his thoughts on the project.

TAHMO

The economics of weather data value may be going up because we’re reaching a cusp in terms of humanity’s consumption of food.

In your TEDx talk you estimate that US weather stations directly bring U.S. consumers  31 billion dollars in value per year. Can Africa see that same kind of return?

Even more.  The economics of weather data value may be going up because we’re reaching a cusp in terms of humanity’s consumption of food.  Africa, one could argue, is the breadbasket for this coming century.  Thus, the value of information about where we could grow what food could be astronomical.  It’s very difficult to estimate.  One application of weather data is crop insurance.  Right now, crop insurance is taking off across Africa. The company we’re working with has 180,000 clients just in Kenya.  When we talked about 31 billion dollars in the U.S., that is the value citizens report, but you need to add to that protection against floods, increased food production, water supply management, crop insurance and a myriad of other basic uses for weather data.  In Africa, the value of this type of protection alone pays for over 1,000 times the cost of the weather stations.

Another application for weather data is that in Africa, the valuation of land itself is uncertain. So if, because of weather station data, we find that a particular microclimate is highly valuable, suddenly land goes from having essentially no value to becoming worth thousands of dollars per acre.  It’s really difficult to estimate the impact the data will have, but it could very well end up being worth trillions of dollars.  We have seen this pattern take place in central Chile, where land went from about $200/hectare in 1998 to over $3,000/ha now due to the understanding that it was exceptionally suited to growing pine trees, which represented a change in land value exceeding $3 billion.

Does the effect of these weather stations go beyond Africa?

There’s limited  water falling on the earth, and if you can’t use weather data to invest in the right seeds, the right fertilizer, and plant at the right time in the right place, you’re not getting the benefit you should from having tilled the soil.  So for Africa the opportunity to improve yields with these new data is phenomenal.  

In terms of the world, the global market for calories is now here, so if we can generate more food production in Africa, that’s going to affect the price and availability of food around the world.  The world is one food community at this point, so an entire continent having inefficient production and ineffective structures costs us all.

TAHMO

If we can generate more food production in Africa, that’s going to affect the price and availability of food around the world.

You’re collecting data from Africa. Is it time to celebrate yet?

I think this is going to be one of those projects where we are always chilling the champagne and never quite drinking it.  It is such a huge scope trying to work across a continent.  So I would say we’ve got some stations all over Africa, we’re learning a lot, and we’ve got collaborators who are excited.  We have reason to feel optimistic.  It will be another five years before I’ll believe that we have a datastream that is monumental.  Right now we’re still getting the groundwork taken care of.  By September of this year we expect to have five hundred of stations in place, and then two years from now, over two thousand. This will be a level of observation that will transform the understanding of African weather and climate.

TAHMO

This is a project of hundreds of people across the world putting their hands and hearts in to make this possible.

How do you deal with the long wait for results?  

In science there is that sense you get when you want to know something, and you can see how to get there.  You have a theory, and you want to prove it.  It kind of captures your imagination.  It’s a combination of curiosity and the potential to actually see something happen in the world: to go from a place where you didn’t know what was going on to a place where you do know what’s going on.  I think about Linus Pauling, who made the early discoveries about the double helix.  He had in his pocket the X-ray crystallography data to show that the protein of life was in helical form, and he said, “In my pocket, I have what’s going to change the world.”  When we realized the feasibility of TAHMO, we felt much the same way.”  

Sometimes in your mind, you can see that path: how you might change the world.  It may never be as dramatic as what Pauling did, but even a small contribution has that same excitement of wanting to be someone who added to the conversation, who added to our ability to live more gracefully in the world.  It’s that feeling that carries you along, because in most of these projects you have an idea, and then ten years later you say, “why was it that hard?”  

Things are usually much harder than your original conception, and that energy and curiosity really helps you through some of the low points in your projects.  So, curiosity has a huge influence on scientific progress.  Changing the world is always difficult, but the excitement, curiosity, and working with people, it all fits together to help us draw through the tough slogs.  In TAHMO, I cannot count the number of people who have urged us to keep the effort moving forward and given a lift just when we needed it most.  This is a project of hundreds of people across the world putting their hands and hearts in to make this possible.  Having these TAHMO supporters is an awesome responsibility and concrete proof of the generosity and optimism of the human spirit.

Learn how you can help TAHMO.

New Weather Station Technology in Africa (Part 2)

Weather data improve the lives of many people. But, there are still parts of the globe, such as Africa, where weather monitoring doesn’t exist (see part 1). John Selker and his partners intend to remedy the problem through the Trans African Hydro Meteorological Observatory (TAHMO).  Below are some challenges they face.

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TAHMO aims to deploy 20,000 weather stations across the continent of Africa in order to fill a hole that exists in global climate data.

Big Data, Big Governments, and Big Unknowns

Going from an absence of data to the goal of 20,000 weather stations offers hope for positive changes. However, Selker is still cautious. “Unintended consequences are richly expressed in the history of Africa, and we worry about that a lot. It’s an interesting socio-technical problem.”  This is why Selker and others at TAHMO are asking how they can bring this technology to Africa in a way that fits with their cultures, independence, and the autonomy they want to maintain. 

TAHMO works with the government in each country stations are deployed in; negotiating agreements and making sure the desires of each recipient country are met. Even with agreements in place, the officials in each country will do what is in the best interest of the people: a gamble in countries where corruption is a factor which must be addressed. Selker illustrates this point by recalling an instance in 1985 when he witnessed a corrupt government official take an African farmer’s land because the value had increased due to a farm-scale water development project.

Most TAHMO weather stations are hosted and maintained by a local school, making it available as an education tool for teachers to use to teach about climate and weather. Data from TAHMO are freely available to the government in the country where the weather station is hosted, researchers who directly request data, and to the school hosting and maintaining the weather station. Commercial organizations will be able to purchase the data, and the profits will be used to maintain and expand the infrastructure of TAHMO.

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Selker says it’s all about collaboration.

Terrorism, Data, and Open Doors

“When I wanted to go out and put in weather stations, my wife simply said, ‘no, you will not go to Chad.’ … because it is Boko Haram central,” Selker says.

The Boko Haram— a terrorist organization that has pledged allegiance to ISIS— creates an uncommon hurdle. Currently the Boko Haram is most active in Nigeria, but has made attacks in Chad, Cameroon, and Niger.

Selker also mentioned similar issues with ISIS, “When ISIS came through Mali, the first thing they did is destroy all the weather stations. So they have no weather data right now in Mali.” Acknowledging the need for security, he adds, “we’re  completing the installation of  eight stations [in Mali] in April.”

“We have good contacts [in Nigeria] and they’re working hard to get permission to put up stations right now in that area. We’ve shipped 15 stations which are ready to install. With these areas we can’t go visit, it’s all about collaboration. It’s about partners and people you know. We have a partnership with a tremendous group of Africans who are really the leading edge of this whole thing.”

weather station

Most TAHMO weather stations are hosted and maintained by a local school.

A Hopeful Future

Despite the challenges of getting this large-scale research network off the ground, Selker and his group remain hopeful.  About his weather data he says, “It’s not glamorous stuff, you won’t see it on the cover of magazines, but these are the underpinnings of a successful society.”

Selker optimistically adds, “We are in a time of incredible opportunity.”

Learn more about TAHMO

Next Week:  Read an interview with Dr. John Selker on his thoughts about TAHMO.

New Weather Station Technology in Africa

Weather data, used for flight safety, disaster relief, crop and property insurance, and emergency services, contributes over $30 billion in direct value to U.S. consumers annually. Since the 1990’s in Africa, however, there’s been a consistent decline in the availability of weather observations. Most weather stations are costly and require highly trained individuals to maintain. As a result, weather stations in African countries have steadily declined over the last seventy years. Oregon State University’s, Dr. John Selker and his partners intend to remedy the problem through his latest endeavor— the Trans African Hydro Meteorological Observatory (TAHMO).

weather stations

Weather data improve the lives of many people. But, there are still parts of the globe where weather monitoring doesn’t exist.

Origins of TAHMO

TAHMO is a research-based organization that aims to deploy 20,000 weather stations across the continent of Africa in order to fill a hole that exists in global climate data. TAHMO originated from a conversation between Selker and Dr. Nick van de Giesen from Delft University of Technology while doing research in Ghana. Having completed an elaborate study on canopy interception at a cocoa plantation in 2006, they hit a “data wall.” There was virtually no weather data available in Ghana, a problem shared by most African countries. This opened the door to what would later become TAHMO.

weather stations

The majority of weather stations are being installed at local schools where teachers are using the data in their classroom lessons.

Logistics and Equipment

Originally Selker and van de Geisen set out to make a $100 weather station, which Selker admitted, “turned out to be harder than we thought.” Not only was making a widely-deployable, affordable, research-grade, no-moving-parts weather station difficult, but additional challenges presented themselves.

“The model of how we might measure the weather in Africa, the whole business model, the production model, infrastructure support, the data-base and delivery system, the agreements with the countries, agreements with potential data-buyers, that all took us a long time to sort-out.” Despite these challenges, in 2010 it started to look feasible. “That’s when we really started to figure out what the technology we were going to use was going to look like.”

After giving a lecture at Washington State University, Selker spoke with Dr. Gaylon Campbell about the project, which led to a long development-deployment-development cycle. Eventually the final product emerged as a low-maintenance, no-moving-parts, cellular-enabled, solar-powered weather station.

weather stations

An estimated 60 percent of the African population earn their income by farming.

Agricultural Benefits of Weather Stations

Crop insurance, a service that is widely used in developed countries, relies on weather data. Once historical data exists, insurance rates can be set, and farmers can purchase crop insurance to replace a crop that is lost to drought, weather, wildfire, etc. On a continent with the largest percentage of the total population subsistence farming, this empowers farmers to take larger risks. Without insurance, farmers need to conserve seed, saving enough to eat and plant again if a crop fails. With crop insurance, crop loss is not as devastating, and farmers can produce larger yields without worrying about losing everything. Hypothetically, this would lead to more food available to the global market, stabilizing food prices year over year.

Crop insurance aside, weather data provide growers with information like when to plant, when not to plant, what crops to plant, and when and if to treat for disease. For rainfed crops, this can mean the difference between a successful yield and a failure.

“Currently in most African countries, the production per acre is about one-sixth of that in the United States. That is the biggest opportunity, in my opinion, for sustainable growth without having to open up new tracts of land. The land is already under cultivation, but we can up productivity, probably by a factor of four, by giving information about when to plant,” Selker comments.  

Despite the social benefits, Selker makes it clear that the TAHMO effort is based on mutual benefit: “We are here for a reason, we want these data to advance our research on global climate processes.  This is a global win-win partnership.”

Learn how you can help TAHMO by getting active.

Next week:  Read about some of the challenges facing TAHMO

German Researchers Directly Measure Climate Change Effects Using TERENO Lysimeters

In Germany, scientists are measuring the effects of tomorrow’s climate change with a vast network of 144 large lysimeters.

lysimeters

The goal of these lysimeters is to measure energy balance, water flux and nutrition transport, emission of greenhouse gases, biodiversity, and solute leaching into the groundwater.

In 2008, the Karlsruhe Institute of Technology began to develop a climate feedback monitoring strategy at the Ammer catchment in Southern Bavaria. In 2009, the Research Centre Juelich Institute of Agrosphere, in partnership with the Helmholtz-Network TERENO (Terrestrial Environmental Observatories) began conducting experiments in an expanded approach.  

Throughout Germany, they set up a network of 144 large lysimeters with soil columns from various climatic conditions at sites where climate change may have the largest impact.  In order to directly observe the effects of simulated climate change, soil columns were taken from higher altitudes with lower temperatures to sites at a lower altitude with higher temperatures and vice versa. Extreme events such as heavy rain or intense drought were also experimentally simulated.

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Lysimeter locations in Germany

Georg von Unold, whose company (formerly UMS, now METER) built and installed the lysimeters comments on why the project is so important. “From a scientific perspective, we accept changes for whatever reason they may happen, but it is our responsibility to carefully monitor and predict how these changes cause floods, droughts, and disease. We need to be prepared to react if and before they affect us.”

How Big Are the Lysimeters?

Georg says that each lysimeter holds approximately 3,000 kilograms of soil and has to be moved under compaction control with specialized truck techniques.  He adds,The goal of these lysimeters is to measure energy balance, water flux and nutrition transport, emission of greenhouse gases, biodiversity, and solute leaching into the groundwater. Researchers measure the conditions of water balance in the natural soil surrounding the lysimeters, and then apply those same conditions inside the lysimeters with suction ceramic cups that lay across the bottom of the lysimeter.  These cups both inject and take out water to mimic natural or artificial conditions.”

lysimeters

Researchers use water content sensors and tensiometers to monitor hydraulic conditions inside the lysimeters.

Researchers monitor the new climate situation with microenvironment monitors and count the various grass species to see which types become dominant and which might disappear. They use water content sensors and tensiometers to monitor hydraulic conditions inside the lysimeters. The systems also use a newly-designed system to inject CO2 into the atmosphere around the plants and soil to study increased carbon effects.  Georg says, “We developed, in cooperation with the HBLFA Raumberg Gumpenstein, a new, fast-responding CO2 enrichment system to study CO2 from plants and soil respiration. We analyze gases like CO2, oxygen, and methane. The chambers are rotated from one lysimeter to another, working 24 hours, 7 days a week.  Each lysimeter is exposed only for a few minutes so as not to change the natural environment.”

Next week:  Read about the intense precision required to move the soil-filled lysimeters, how problems are prevented, and how the data is used by scientists worldwide.

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Top Five Blog Posts in 2016

In case you missed them the first time around, here are the most popular Environmental Biophysics.org blog posts in 2016.

Lysimeters Determine if Human Waste Composting can be More Efficient

Top five blog posts Environmental biophysics

In Haiti, untreated human waste contaminating urban areas and water sources has led to widespread waterborne illness.  Sustainable Organic Integrated Livelihoods (SOIL) has been working to turn human waste into a resource for nutrient management by turning solid waste into compost.  Read more

Estimating Relative Humidity in Soil: How to Stop Doing it Wrong

Top five blog posts Environmental biophysics

Estimating the relative humidity in soil?  Most people do it wrong…every time.  Dr. Gaylon S. Campbell shares a lesson on how to correctly estimate soil relative humidity  from his new book, Soil Physics with Python, which he recently co-authored with Dr. Marco Bittelli.  Read more.

How Many Soil Moisture Sensors Do You Need?

Top five blog posts Environmental biophysics

“How many soil moisture sensors do I need?” is a question that we get from time to time. Fortunately, this is a topic that has received substantial attention by the research community over the past several years. So, we decided to consult the recent literature for insights. Here is what we learned.

Data loggers: To Bury, or Not To Bury

Top five blog posts Environmental biophysics

Globally, the number one reason for data loggers to fail is flooding. Yet, scientists continue to try to find ways to bury their data loggers to avoid constantly removing them for cultivation, spraying, and harvest.  Chris Chambers, head of Sales and Support at Decagon Devices always advises against it. Read more

Founders of Environmental Biophysics:  Champ Tanner

Top five blog posts Environmental biophysics

Image: http://soils.wisc.edu/people/history/champ-tanner/

We interviewed Gaylon Campbell, Ph.D. about his association with one of the founders of environmental biophysics, Champ Tanner.  Read more

And our three most popular blogs of all time:

Do the Standards for Field Capacity and Permanent Wilting Point Need to Be Reexamined?

Top five blog posts Environmental biophysics

We asked scientist, Dr. Gaylon S. Campbell, which scientific idea he thinks impedes progress.  Here’s what he had to say about the standards for field capacity and permanent wilting point.  Read more

Environmental Biophysics Lectures

Top five blog posts Environmental biophysics

During a recent semester at Washington State University a film crew recorded all of the lectures given in the Environmental Biophysics course. The videos from each Environmental Biophysics lecture are posted here for your viewing and educational pleasure.  Read more

Soil Moisture Sensors In a Tree?

Top five blog posts Environmental biophysics

Soil moisture sensors belong in the soil. Unless, of course you are feeling creative, curious, or bored. Then maybe the crazy idea strikes you that if soil moisture sensors measure water content in the soil, why couldn’t they be used to measure water content in a tree?  Read more

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Soil Moisture: An Important Parameter in Weather Monitoring

CoCoRaHS and Weather Monitoring

Each time a rain, hail, or snow storm crosses over your area, volunteers are taking precipitation measurements that are then used to analyze situations ranging from water resource availability to severe storm warnings.  

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CoCoRaHS precipitation data is used by many high profile organizations.

CoCoRaHS (Community Collaborative Rain, Hail and Snow Network) is a non-profit community-based network of volunteers of all ages and backgrounds working together to measure and map precipitation (rain, hail and snow).  Their data is used by the National Weather Service, meteorologists, hydrologists, emergency managers, city utilities, USDA, engineers, farmers, and more.  The organization will soon add another layer to their weather-monitoring efforts:  soil moisture measurement.

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In 1997, a localized flooding event in Fort Collins, Colorado was not well-warned due to lack of high-density precipitation observation.

Why Soil Moisture?

CoCoRaHS originated as the brain child of Nolan Doesken, the state climatologist of Colorado,  in 1997 in response to a localized flooding event in Fort Collins, CO that was not well-warned due to lack of high-density precipitation observations.  Ten years ago the Colorado Climate Center began a partnership with the National Integrated Drought Information System to establish the first regional drought early warning system. This particular system would serve the Upper Colorado River Basin and eastern Colorado.

From the beginning, Nolan was thinking about soil moisture.  He says, “When we first started this project, we identified one weakness of the current climate monitoring systems as the inability to quantitatively assess soil moisture.  Soil moisture is critical as it affects both short term weather forecasts and long-term seasonal forecasts, which are important for drought early warning and avoiding the agricultural consequences of too much or too little soil moisture.”It wasn’t until years later in the drought of 2012, which developed rapidly in the mid and late spring across the intermountain west and central plains that Nolan began planning to use CoCoRaHS as a vehicle for improving the soil moisture aspect of drought early warning.

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The organization intends to measure soil moisture using the gravimetric method.

How Will Volunteers Measure Soil Moisture?

Historically, CoCoRaHS has had success using low-cost measurement tools, stressing training and education, and using an interactive web-site to provide the highest quality data, and soil moisture will be no different.  The organization intends to measure soil moisture using the gravimetric method, where the user will take samples using a soil ring, dry samples in their own oven, and measure sample weight with an electronic scale. Peter Goble, a research assistant at Colorado State, has developed the measurement protocols that volunteers will follow.  He says, “We have installed several different types of soil sensors and tried gravimetric techniques in a field next to the center, and our experience has helped us set up a protocol that gets observers as educated as they can be by the time they take their measurements. The coring device we use is something that came about through trial and error. We were trying to reconcile the fact that we really wanted deeper root zone measurements in order to satisfy drought early-warning-system users, and the need for an inexpensive set of standardized materials that we could send out to observers in a kit.”  Volunteers will take soil samples at each point in a grid pattern, both at the surface and at the 7-9 inch level near the root zone.

What will Happen to the Data?

Initially, while the program is in its test phase, the data will be put in a spreadsheet and shared. However, once CoCoRaHS has finished sending this protocol around the nation to a group of alpha testers, they’ll set up a website infrastructure enabling volunteers to enter their VWC data directly into the CoCoRaHS website.

The need for soil moisture measurement in weather monitoring will outweigh the volunteers’ ability to measure, but there is a solution.

The need for soil moisture measurement in weather monitoring will outweigh the volunteers’ ability to measure, but there is a solution.

Why the Gravimetric Method?

Nolan says the challenge of water content is that soil is highly variable across space.  And if you add issues like sensor performance, improper installation of sensors, problems with soil contact, changes in bulk density, and soil compaction, you end up with inconsistent data.  The gravimetric method will avoid inconsistencies in spatial measurements and ensure higher quality data.

An Overwhelming Task

Nolan says the need for soil moisture measurement in weather monitoring will outweigh the volunteers’ ability to measure, but there is a solution. “People who use soil moisture data in atmospheric applications need high resolution, gridded information in every square kilometer across the country, but it will happen through modeling.  The measurements we take of precipitation and soil moisture will help in the refinement of the weather modules the atmospheric scientists will use as input to their weather prediction models.”

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Unraveling the Effects of Dams in Costa Rica

Thirty years ago, in Costa Rica’s Palo Verde National Park, the wetlands flooded regularly and eco-tourists could view thousands of waterfowl. Today, invasive cattail plants cover portions of the wetland which has subsequently dried up and become colonized by hardwoods. Consequently, the number of birds has fallen dramatically.

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The number of birds on Palo Verde National Park has fallen dramatically. (Image: anywherecostarica.com)

Some people blame the dams built in the 1970’s which introduced hydrological power and created a large irrigation district in the remote region. Dr. Rafael Muñoz-Carpena, Professor and University of Florida Water Institute Faculty Fellow and his research team are performing environmental studies on the wetlands, trying to unravel the effects of the dams and how to revert some of the damage. Rafael explains, “We have a situation where modern engineering brought about social improvements, helpful renewable resources, and irrigation for abundant food production. But the resulting environmental degradation threatens a natural region in a country that depends on eco-tourism.”

dams

“A vast network of mangrove-rich swamp, lagoons, marshes, grassland, limestone outcrops, and forests comprise the 32,266 acre Palo Verde National Park.” (Image and text: anywherecostarica.com)

Are The Dams Responsible?

Dr. Muñoz-Carpena says because of lack of historical data it’s difficult to untangle and separate all the factors that have caused the environmental degradation. He adds, “Thirty years ago Palo Verde National Park was part of a large wetland system which was important to all of Central America because it contained many endangered species and was a wintering ground for migratory birds from North America. The Palo Verde field station on the edge of the wetland, operated by the Organization of Tropical Studies (OTS), attracted birdwatchers and wetland scientists from all over the world.”

In the 1970’s, with international funding, a dam was built in the mountains to collect water from the humid side of Costa Rica in order to generate hydroelectric power. It was clean, abundant, and strategically important.  With the water transferred to the dry side of the country, a large irrigation district was created to not only produce important crops to the region like rice and beans, but to distribute the land among small parcel settlers.

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“Birding is the principal draw of visitors to the park.” (Image and text: anywherecostarica.com)

Over the years, however, the wetland area slowly degraded to the point where its Ramsar Convention wetland classification is under question. Rafael says that understanding the causes of the degradation, the impacts of the human system, and how the natural and human systems are linked, is the big question of his research, and there are many factors to consider. “The release of the water, ground and surface water (over)use, agriculture, human development, and a larger population are all factors that could contribute to this degradation. Everything compounds in the downstream coastal wetlands. In collaboration with OTS and other partner organizations and universities, we are trying to disentangle these different drivers.”

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Understanding the causes of the degradation, the impacts of the human system, and how the natural and human systems are linked, is the big question of this research. (Image: anywherecostarica.com)

A Lack of Historical Data

One of the challenges the researchers face is to gather a sufficient amount of temporal and spatial information about what happened in the past forty years.  There are no public repositories of data to tap, and the information is spotty and hard to access. Rafael says, “Thanks to the collaboration of many local partners, we have been able to gather enough information to stitch together a large database out of a collection of non-systematic studies. The biggest challenge is to harmonize data that has been collected by different people in non-consistent ways.” This large database now contains the best long-term record possible for key hydrologic variables: river flow, groundwater stage, precipitation, and evapotranspiration.

The team is also using remote sensing sources to try to obtain time-series data for land-use and vegetation change, and will have those data ground truthed through instruments that are collecting similar time-series data. Rafael says, “The idea is to build a network that will allow us to overlap some of the previous data sources with our own, validate and upscale the ground data with remote sensing sources, enabling us to put together a detailed picture of what happened.”

Next Week:  Find out how the researchers established connectivity in such a remote area,  some of the problems associated with the research, and how the team has addressed those issues.

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Can Canopy Measurements Determine Soil Moisture? (Part 2)

Dr. Y. Osroosh, now a researcher at Washington State University, believes that plants are the best soil moisture sensors (see part 1).  He and his team have developed a new model for interpreting plant canopy signals to indirectly determine soil moisture in a Fuji apple orchard.  Below are the results of their efforts and what he sees as the future of this research.

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Could plants be the best indicators of soil moisture?

The Results

Osroosh says they expected to see correlations, but such strong relationships were unexpected. The team found that soil water deficit was highly correlated with thermal-based water stress indices in drip-irrigated apple orchard in the mildly-stressed range. The relationships were time-sensitive, meaning that they were valid only at a specific time of day. The measurements taken between 10:00am and 11:00am (late morning, time of maximum transpiration) were highly correlated with soil water deficit, but the “coefficient of determination” decreased quickly and significantly beyond this time window (about half in just one hour, and reached zero in the afternoon hours).  Osroosh says this is a very important finding because researchers still think midday is the best time to measure canopy water stress index (CWSI). He adds, “The apple trees showed an interesting behavior which was nothing like what we are used to seeing in row crops. They regulate their stomata in a way that transpiration rate is intense late in the morning (maximum) and late in the afternoon. During the hot hours of afternoon, they close their stomata to minimize water loss.”

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Researchers have found good relationships between CWSI and soil water content in the root zone near the end of the season at high soil water deficits in row crops.

Other Research

Osroosh points to other efforts which have tried to correlate remotely-sensed satellite-based thermal or NIR measurements to soil water content. He says, “The closest studies to ours have been able to find good relationships between CWSI and soil water content in the root zone near the end of the season at high soil water deficits in row crops. Paul Colaizzi, a research agricultural engineer did his PhD research in part on the relationship between canopy temperature, CWSI, and soil water status in Maricopa, Arizona; also motivated by Jackson et al. (1981). Steve Evett and his team at Bushland, Texas are continuing that research as they try to develop a relationship between CWSI and soil water status that will hold up. They are using a CWSI that is integrated over the daylight hours and have found good relationships between CWSI and soil water content in the root zone near the end of the season when plots irrigated at deficits begin to develop big deficits.”

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Osroosh wants to study other apple cultivars, tree species, and perhaps even row crops, under other irrigation systems and climates.

What’s The Future?

In the future Osroosh hopes to study the limitations of this approach and to find a better way to monitor a large volume of soil in the root zone in real-time (as reference). He says, “We would like to see how universal these equations can be. Right now, I suspect they are crop and soil-specific, but by how much we don’t know. We want to study other apple cultivars, tree species, and perhaps even row crops, under other irrigation systems and climates. We need to monitor crops for health, as well, to make sure what we are measuring is purely a water stress signal. One of our major goals is to develop a sensor-based setup which, after calibration, can be used for “precise non-contact sensing of soil water content” and “stem water potential” in real-time by measuring canopy temperature and micrometeorological parameters.”

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