Friday, July 17, 2015

Scaling Plant Traits

Current Earth system models represent Arctic plant traits with a mean value that does not vary with time or space.  We’re working towards approaches that will provide rich descriptions of plant traits for next generation models that will enable the representation of spatial and temporal variation in several key model parameters.  To achieve this goal we are building relationships between plant functional and structural traits and spectral signatures of plant leaves and canopies so that we can leverage near surface, airborne and ultimately space borne remotely sensed data to retrieve these plant traits.

We’ve spent the last week working towards that goal.  Shawn and Wil have been scanning plant canopies and Kim and I and been following them around measuring physiological properties before handing our leaves back to Shawn and Wil for measurement of leaf level spectra.  We’re hoping to demonstrate that leaf level relationships between spectra and plant traits translate to canopy level measurements that can be used to retrieve physiological properties across time and space and in the near term hope to apply these relationships to observations from the NGEE-Arctic tram.

Monday, July 13, 2015

Hydrology Tracer Study Gets Underway...

Nathan Wales, NGEE Hydrology Masters Student from New Mexico Tech, working with LANL NGEE hydrologists Brent Newman and Cathy Wilson, is putting the finishing touches on the deployment of water sampling and measurement equipment that will be used to carry out a tracer experiment at the Barrow Environmental Observatory NGEE Arctic intensive field site. The NGEE team deployed 75 macro-rhizons over the past 2 days, in order to collect soil water samples at multiple soil depths across two polygons types in order to track and quantify the role of polygon surface and frost table micro-topography in controlling subsurface horizontal flow of water in the landscape. 

Nathan installs a collar (green tube) around a well hole to ensure that the dilute sodium bromide tracer cannot flow into the well hole through surface water pathways during rain events.  Brent Newman (background) installs the macro-rhizons at 15cm, 25 cm and 35 cm below the ground surface. Subsurface soil water samples collected with the macro-rhizons will be analyzed in the BARC laboratory to quantify how fast the tracer applied at the surface of the high center polygon will infiltrate into the soil and move sideways through the subsurface down to the subsoil in the troughs.

 Most global climate models assume that all subsurface water flux is one dimensional, in the vertical direction; driven into the soil by gravity and negative soil water pressures (suction) during rainfall, and drawn out of the soil and into the atmosphere by evaporation and plant transpiration. But analysis of new NGEE in-situ geochemical data, and analysis of seasonal inundation patterns using remote sensing data, both suggest that horizontal water flow, well after snow melt, may be important in determining the spatial distribution of chemical constituents and biogeochemical processes in low relief Arctic coastal plain environments. Water level and tracer data will be used together to inform NGEE’s Arctic Terrestrial Simulator, that will be used to help interpret the tracer study results and improve our understanding of water and chemical constituent transport in the Arctic. 

Nathan programs the water level sensor to record water levels every 10 minutes in the shallow (1m deep) wells deployed across the polygons.
UTEP researchers, Florencia and Steve, visit the low center polygon tracer study site to photograph NGEE wells for Craig Tweedie’s BAID GIS project. BAID archives and serves GIS and other spatial data for all research activities in the BEO. 

Golden plover inspects experimental design.


Monday, July 6, 2015

Pics of the Trip...

It was a great two weeks of research in Barrow. I always enjoy working with colleagues and helping them, where possible, accomplish their project-related objectives. Members of our NGEE Arctic team will continue to come and go on the North Slope throughout the field season. We also have a large team of scientists visiting the Seward Peninsula in late July and early August to evaluate possible field sites for our proposed Phase 2 research activities. I’ll be sure to provide daily postings to the blog during that trip. Until then here are a few of my favorite pictures taken this past couples of weeks. Special thanks to Ori Chaffe for contributing her photos.