1. Analyzing Arctic Ecology Using Networked Infomechanical Systems*
Nathan C. Healey1, Steven F. Oberbauer1, Robert D. Hollister2, Craig E. Tweedie3,
Jeffrey M. Welker4, William A. Gould5, A. Joshua Leffler4
1. Florida International University 2. Grand Valley State University 3. University of Texas, El Paso
4. University of Alaska, Anchorage 5. USDA Forest Service, International Institute of Tropical Forestry, Rio Piedras, Puerto Rico
*2012 AGU Abstract # C13E-0676
Abstract
Instrumentation and Transect Diagrams
Observations from the Alaskan NIMS Systems
Understanding ecological dynamics is important for investigation into the potential impacts of climate change in the Arctic. Established in the early 1990’s, the International Tundra Experiment (ITEX) began observational inquiry of plant phenology, plant growth, community composition, and ecosystem properties as part of a greater effort to study changes across the Arctic. Unfortunately, these observations are labor intensive and time consuming, greatly limiting their frequency and spatial coverage. We have expanded the capability of ITEX to analyze ecological phenomenon with improved spatial and temporal resolution through the use of Networked Infomechanical Systems (NIMS) as part of the Arctic Observing Network (AON) program. The systems exhibit customizable infrastructure that supports a high level of versatility in sensor arrays in combination with information technology that allows for adaptable configurations to numerous environmental observation applications. We observe stereo and static time-lapse photography, air and surface temperature, incoming and outgoing long and short wave radiation, net radiation, and hyperspectral reflectance that provides critical information to understanding how vegetation in the Arctic is responding to ambient climate conditions. These measurements are conducted concurrent with ongoing manual measurements using ITEX protocols. Our NIMS travels at a rate of three centimeters per second while suspended on steel cables that are ~1 m from the surface spanning transects ~50 m in length. The transects are located to span soil moisture gradients across a variety of land cover types including dry heath, moist acidic tussock tundra, shrub tundra, wet meadows, dry meadows, and water tracks. We have deployed NIMS at four locations on the North Slope of Alaska, USA associated with 1 km2 ARCSS vegetation study grids including Barrow, Atqasuk, Toolik Lake, and Imnavait Creek. A fifth system has been deployed in Thule, Greenland beginning in Once compiled and quality controlled, all of our data are freely available online via the Arctic Observing Network’s Advanced Cooperative Arctic Data and Information Service (ACADIS). Here we present some of our findings to show how our results can be advantageous to various disciplines including plant ecology, hydrology, geology, atmospheric sciences, and remote sensing. For instance, we found that albedo decreases with increasing NDVI after initial green-up and loss of dead standing litter (DOY ), displaying an r2 of 0.90 in 2012 at Toolik Lake. This relationship is vital for determining phonological events via remote sensing and understanding the surface energy balance that impacts atmospheric processes, weather and climate, the hydrologic cycle, and ecophysiological progression throughout the short arctic growing season. Scaling these data to larger scales, which is critical to future monitoring of the potential impacts of climate change on arctic vegetation, is facilitated by linkage of measurements along the NIMS transects and manual vegetation measurements in the 1 km2 sample grids with frequent low-altitude aerial photography.
2012 Averages
Table 1. Average values from various instrumentation installed on the NIMS Systems
Figure 5. The NIMS system including all instruments (A & B). Included are displays of the CR3000 data logger, the Ocean Optics A B C D E F
JAZ Spectrometer with fiber optics and the power supply (C), the CR200 data logger for the motor (D), the magnetic counter wheel (E), and the PlantCam which captures a picture every half hour.
Campbell Scientific CR3000 data logger
Campbell Scientific CR200 data logger
Photovoltaic Cells
Mini-PC laptop computer
Two towers ~50 m apart
Fuji stereo (3-D) imaging camera
Figure 7. Plots of air temperature (Tair) and surface temperature (Tsfc) over the 2012 field season at Barrow (A), Atqasuk (B), Toolik Lake (C), and Imnavait Creek (D).
Kipp and Zonen CNR4 Net Radiometer
Ocean Optics JAZ Spectrometer
Trimble GreenSeeker NDVI sensor
(Red = 660nm , Near Infrared = 770nm)
Apogee SI-111 Infrared Thermometer
Campbell Scientific SR50A Sonic Distance
Plant Camera
Figure 8. Average NDVI in 2012 for the four Alaskan sites with an inset displaying the relationship between albedo and NDVI after initial green-up at Toolik Lake.
Figure 4. Diagrams of the NIMS transects at Barrow(A), Atqasuk (B), Toolik Lake (C), and Imnavait Creek (D). Each depiction displays transitions from one major functional type to the next along each transect. B C D A B C A D F G E H
Figure 9. Normalized Difference Vegetation Index (NDVI) observations acquired by the Trimble GreenSeeker NDVI sensor at Barrow (A), Atqasuk (B), Toolik Lake (C), and Imnavait Creek (D), and comparisons of NDVI observations between the Trimble GreenSeeker and the Ocean Optics JAZ Spectrometer on 19 June (E), 9 July (F), 5 August (G), and 22 August 2012 (H).
2012 Seasonal NDVI
Toolik Lake
Dry Heath
Shrub
Tundra
Moist Acidic Tundra
Wet Acidic Tundra
Imnavait Creek
Atqasuk
Wet Meadow
Carex sp.
Barrow
Figure 5. Images of the Alaskan transects from ground level showing the different functional types present at each location.
Imnavait Creek
10 m
Barrow
Atqasuk
10 m
Toolik Lake
10 m
Research Setting and Questions
What form will new arctic plant communities take and what are the processes driving these changes?
What will the ecosystem properties and function of these new plant communities be?
How will these changes in ecosystem properties scale to regional and global level?
Toolik Lake
Imnavait Creek
Barrow
Atqasuk
Thule, Greenland
10 m
Conclusions
Figure 6. Aerial images of the Alaskan transects showing the different functional types present at each location.
Collecting critical information toward a better understanding of how vegetation in the Arctic is responding to ambient climate conditions including analyses of growth, phenology, and ecosystem function.
Collaborative effort among institutions striving to combine efforts in analyzing labor intensive site-specific/plot-level vegetative analysis with a variety of remote sensing technologies that do not have the same labor intensity requirements.
Advantageous to various disciplines including plant ecology, hydrology, geology, atmospheric sciences, and remote sensing.
Reflectance data can be useful for analysis of changes in plant status including chlorophyll content, photosynthetic activity, water content, and greenness.
Data is made freely available via the Advanced Cooperative Arctic Data and Information Service (ACADIS).
Aspirations for full automation of the systems to reduce the need for researchers on-site and for greater data acquisition capability.
Collaboration
and Scaling
This project is funded by NSF Grant OPP The authors of this work owe a debt of gratitude for aid in field work, logistical support, and completion of other vital facets of this research including Dr. Hella Ahrends, Sergio Vargas, Jennifer Liebig, Kelseyann Kremers, Jose Luciani, Ed Metzger, Dr. Paulo Olivas, Jeremy May, Jonathan Moser, the Toolik Lake Biological Field Station Staff, CH2MHill Polar Services, and UMIAQ Logistics.
Acknowledgements
Point Framing
Networked Infomechanical
Systems
Kite Aerial
Photography
Unmanned Aerial
Vehicle
Satellite
Figure 1. Map of Alaska with stars indicating research locations at Barrow (Red), Atqasuk (Yellow), Toolik Lake (Blue), and Imnavait Creek (Orange).
Figure 2. Image of Greenland with a star indicating the research location at Thule.