University of Idaho MESA Network – 3D Wireless Sensor Network for Terrain-Climate Research in Remote Mountainous Environments
Recent climate changes have demonstrated that human society has a profound impact on nature, on a global scale. We are only beginning to understand the complex processes that govern natural ecosystems on our planet, and our interactions with them. Even remote mountainous environments are affected by climate change and human activities. Despite their rugged appearance, these rather fragile ecosystems are threatened by changes in global temperature and precipitation patterns.
A considerable portion of human civilization lives at the base of mountains, or near watersheds that originate in the mountains and within weather patterns that are shaped by those same mountain areas. A significant portion of the world’s forests are located in mountainous areas and they are a crucial element in shaping weather patterns and hydrological cycles. Forests are not only a source of vital oxygen on our planet, they also provide a source of clean water, food, and are a habitat for many species. They help mitigate global warming by acting as a carbon sink. That’s why deforestation is one of the most negative impacts humans have had on natural ecosystems. Deforestation not only shrinks the size of our forests and upsets the global CO2 balance, it also causes erosion and with it a decline in the health and stability of our watersheds. These changes express themselves as increased flooding, deteriorating water quality, and declining fish populations.
As human civilization expands, our planet’s natural ecosystems are changing, in many cases in detrimental ways. This is often caused by our lack of knowledge and awareness about how we humans interact with nature, and how nature actually operates. Clearly, a more comprehensive understanding of natural ecosystems is required, and of the interactions between these systems and human activities.
That is one of the reasons why more and more recent efforts by scientists have focused on modeling natural ecosystems and visualizing their processes. “We use models to help us peer into the future", says Katy Kavanagh, a professor at the College of Natural Resources at the University of Idaho. Kavanagh and her research team at the Forest Ecology and Biogeosciences Department are investigating climate change impacts in remote mountainous forestlands. They aim to improve our understanding of processes that control carbon and water cycles, and how climate change affects them. By deploying sensors in and around trees in mountainous terrains, they hope to gather data that will allow them to ultimately visualize and model ecosystem processes in mountainous regions.
Kavanaghs team chose the Taylor Wilderness Research Station (TWRS) as study site for their research project, a remote, pristine, mountainous wilderness area that has seen little to no human impact. The TWRS site is ideal for monitoring because it has not been locally altered by human activities, revealing how climate change is affecting natural habitats. Data collected in this pristine region can be used as a benchmark for climate change research.
The team designed a complex 3-dimensional wireless sensor system to gather data needed for their ecosystem model. They named their sensor network the “Mountainous Ecosystem Sensor Array” or MESA for short. MESA is a hierarchical wireless network with three different sensor types aggregating data from three elevations, each about 1 km apart. At each elevation, there are soil, canopy, and atmospheric sensors transmitting data to a base station located at the TWRS cabin.
The remoteness of the site and the mountainous terrain make it very difficult to deploy sensors. Kavanagh says, “Paradoxically, the factors that make these remote, natural sites challenging for sensor networking are often what make them indispensable for climate change research.” The MESA team also faced the challenge of needing to deploy many of their sensors at the top of trees, requiring hazardous climbing to mount them. Other challenges include transmitting wireless signals through leaves and branches and across rugged terrain, and providing enough power to all sensor stations.
Kavanagh’s fellow researcher Paul Robinson and his engineers evaluated a number of currently available wireless sensor systems, and decided to use the InteleCell and InteleMote wireless data loggers in their project. Derek Neal, a MESA team member, said: “Intelesense quickly became the preferred choice for network devices mostly due to their superb technical support, user-friendly and robust format, and flexibility. Furthermore, they had solved and provided a large piece of the system design: data storage and presentation. Many of the MESA sensors already had drivers available and the remaining drivers were written by Intelesense. They were willing to collaborate closely during the design process helping to solve the obstacles of implementation. Such customer service was absent from all other explored companies.”
Intelesense was able to rapidly interface environmental sensors selected by the MESA team to the InteleCell and InteleMote devices. These sensors included:
- Vaisala HMP155 - Air Temperature and Relative Humidity Sensor
- Vaisala GMP343 - Carbon Dioxide
- Vaisala WXT520 - Weather Station (Wind Speed and Direction, Rainfall, Air Temperature, Relative Humidity, Barometric Pressure)
- Stevens Hydra Probe II - Soil Water and Soil Temperature
- Hukseflux NR01 - Solar Radiation
- Judd Communications Depth Sensor - Snow Depth
- ICT International DR26 Band Dendrometer - Tree Trunk Circumference
- Decagon Leaf Wetness Sensor - Leaf Wetness
These sensors were used to monitor atmospheric, hydrological, and biospheric conditions in and around three main trees, each at a different elevation. InteleCells were mounted at the top of these trees and InteleMotes were used for gathering data from individual sensors that were mounted at various points of the main tree as well as other trees within a few hundred feet of the main tree. The InteleCells with their long-range transmitters formed a back-bone wireless network that spanned from the TWRS cabin to the top of the mountain range, while the smaller InteleMotes created “micronets” - mesh network clusters around each main tree. This functional subdivision created both a cost effective and power effective solution. And since InteleMotes are able to transmit their data over distances of up to 4 miles with simple dipole antennas, the three micronets of InteleMotes can even talk to each other, which increases the robustness of the MESA network. This communications redundancy combined with the fact that InteleCells and InteleMotes share the same hardware interfaces and sensor drivers offered the MESA team a lot of flexibility in designing their sensor network.
InteleCells and InteleMotes sample all sensors every 15 minutes, and transmit their data to the TWRS base station at the same rate. From there, the data is uploaded to the Intelesense Data Exchange server which can be accessed by researchers via the Internet to view and download data. MESA researchers can also change the settings and configuration of each site remotely using the Intelesense website.
One concern Kavanagh had for the InteleCells was their ability to operate at full capacity in Idaho’s harsh winter conditions. Intelesense Technologies designed an “extreme-cold” InteleCell for the University of Idaho. This cold-weather adapted InteleCell can withstand temperatures as low as -70°C because it is equipped with a battery heater that is activated when the InteleCell temperature drops below a user-defined temperature, and enclosed by a NASA-developed Aerogel thermal insulation sleeve.
The data collected at Taylor Wilderness Research Station will benefit a broad scientific community, primarily in ecology, conservation, biology, and environmental science. The University of Idaho plans to use this research to educate students about the effects of climate change and to inspire a conversation about mitigating potential effects of climate change in mountainous ecosystems. An interactive portal on collaborate.org will allow University of Idaho researchers to share the information with people beyond the research lab. This portal allows users to overlay the collected sensor data with other geospatial data layers available for the area.