The vertical distribution of plant roots in the soil profile is a key trait modulating plant contributions to soil carbon storage, drought and nutrient stress resistance, yield, and fitness. However, direct sampling of deep roots requires massive effort, so existing data are sparse and many researchers have adopted modeling approaches to fill data gaps and generate hypotheses about how soil properties change the biogeochemical, agricultural, ecological, and hydrologic consequences of root depth. Such models are useful only if they correctly represent the processes of interest and give accurate predictions of the root systems they simulate. Most current root growth models represent soil as a uniform and unrestrictive medium. This is often a reasonable simplification when modeling roots grown in pots or artificial media, but is less so for field soils which often increase in density, hardness, and heterogeneity with depth. To better predict the effect of soil hardness on root distribution, we updated the structural-functional root growth model OpenSimRoot to explicitly predict soil hardness from soil bulk density, water content, porosity, and depth. Root growth impedance is curently represented by linear scaling of the root elongation rate according to soil hardness. Future work will incorporate configurable growth responses and allow hardness to control changes in root diameter and growth direction, thus allowing the model to examine the fitness implications of carbon reallocation in complex structured soils. Our updated OpenSimRoot captured >50% of observed variation in penetrometer resistance from field soils. When we incorporated soil hardness into simulations of maize growth, we observed a substantial reduction in the predicted root:shoot ratio that overwhelmed previous model predictions of increased water uptake from steeper root angles. These findings reinforce that models considering costs and benefits of deep rooting should routinely consider soil hardess.

Rangelands cover over 50% of the land surface area in the western US, providing important economic, social and environmental benefits. The resilience of western rangelands, however, is threatened by climate change, including altered phenology and precipitation patterns, increased frequency and intensity of drought and forest fires, heightened pressure from invasive plants, and reduced water storage in winter snowpack. Climate adaptation strategies are available to ranchers, yet uptake varies substantially. Rancher decision-making is a complex function of their beliefs, knowledge, skill level, risk perceptions, and the institutions supporting them. Semi-structured interviews, focus groups and workshops will be utilized to examine how ranchers in Idaho, Montana, Wyoming perceive and respond to climate change, and the opportunities and barriers these social processes create for climate change adaptation.

An unanswered question in planetary science is how could the early Martian atmosphere have maintained a greenhouse effect sufficient to allow for liquid water on the surface? A recent study by Wordsworth et al. (DOI:10.1002/2016GL071766) suggested that previously unaccounted-for collision-induced absorption (CIA) by carbon dioxide (CO2) and hydrogen gas (H2), and by CO2 and methane (CH4) could provide the additional atmospheric absorption needed to trap enough radiation to raise the Martian surface temperature above freezing. However, as CIA cross-sections for CO2-H2 and CO2-CH4 complexes do not exist in the literature, the authors could only use computational methods to simulate the CIA absorption cross-sections that they themselves identify in the study as needing experimental validation. Preliminary results will be presented from experimental measurements of the CIA cross-sections for CO2-H2 and CO2-CH4 complexes performed using Fourier Transform Spectroscopy. We have obtained Beam-time at the Canadian Light Source Far-IR beamline in late October and early November which will allow us to derive Cross-sections over a spectral range of 0-3000 cm-1 and a temperature range of 200-350 K. In addition to allowing us to experimentally validate the hypothesis of Wordsworth, the cross-sections so obtained can also be applied to other planetary systems with CO2-rich atmospheres, such as Venus, and will be useful to terrestrial spectroscopists.

Forests are becoming drier due to a warming climate thus increasing the risk of wildfires. In recent years, wildfires have grown larger and more severe. In the U.S., over 80% of wildfires are human-caused and such events can substantially extend the fire season. At the same time, more and more people are living in areas where wildfires can burn. Recent fires have illustrated the devastating consequences of fires in the Wildland Urban Interface (WUI). In this context, the ability to rapidly assess fuel load is crucial in assessing and managing the risk of wildfires. Current methods for monitoring fuel loads (e.g., FIREMON, Brown’s Transect) are accurate but time- and personnel-intensive. The Global Learning and Observations to Benefit the Environment (GLOBE) Observer Fire Fuel app is being developed using the Photoload Sampling Technique to offer options in rapidly assessing fuel loads by 1) providing citizen scientists with a fast and easy method to monitor WUI fuel loads, enabling them to contribute to the knowledge of fuels in their communities, and empowering them to think more about how fuels might be managed in their area; and 2) offering natural resource managers and fire science researchers a detailed, scientific application that primarily aids experts already studying fuels to better collect the fuels data they need. This poster will provide an overview of the GLOBE Observer Fire Fuel app and the current app development status. We will highlight the value and opportunity the power of smartphones and tablets offer to rapidly assess fuel loads via an app-based method compared to collecting the data on paper. We greatly welcome input from the fire science community at this point of the fire fuel app development.

Human activities have been changing deposition rate of the atmospheric reactive N over the last decades. The understanding of the process that rules the accumulation and deposition of reactive nitrogen in the environment still faces major gaps mainly in regions with lack of data as South America. In this work, we evaluated the atmospheric dry deposition of reactive nitrogen (Nr) using concentration measurements of different chemical species, in six sampling sites with different environmental characteristics in the state of São Paulo, Brazil, for a sampling period of approximately 24 months (2015-2017). We used the sampling system DELTA (Sampler for Atmospheric Sampling of Long Term), and ion chromatography method to determine the concentration of gaseous (NH3 and HNO3), and particulate (NH4+ and NO3-) chemical species in the atmosphere. The N-NH3 (gaseous) was the dominant form of Nr in the atmosphere at all sampling sites. The highest N-NH3 mean value was found near the urban area of the municipality of São Paulo (SP, 1.58 ± 0.73 μgN m-3) and the lowest mean value in the most eastern sampling site (0.26 ± 0.26 μgN m-3). The high values in the SP sampling site is related to the intense traffic in the metropolitan area and, also to waste management, industrial NH3, and human emissions as observed in other urban areas around the world. The particulate N-NH4+ is the second most common form of Nr in the São Paulo state atmosphere. The other forms of Nr in the atmosphere, the gaseous HNO3 and particulate NO3, represent only about 10% of the total Nr in the atmosphere each. The total gaseous Nr concentration was a factor of 1.7 larger than particulate Nr. The Nr deposition varied throughout the years. We did not observe a pattern of variation linked to meteorological characteristics of dry and wet season, as observed in other regions of the globe. However, we found good correlation with wind speed higher than 3.5 m s-1 and humidity. Our results provide the first spatial analysis of Nr deposition using in situ data in a Latin American region and will contribute to the understanding of nitrogen balance and to improve Nr deposition modelling approaches. This study was supported by the project Nitrogen cycling in Latin America: drivers, impacts and vulnerabilities (Nnet, IAI/CRN3005 and FAPESP 2012/06416-1), PCI Program of the MCTIC, and collaborators.

When NASA established the Planetary Data System (PDS) in the late 1980s, its mandate to the PDS was not merely to preserve the bytes from NASA’s planetary science missions, but to maintain the usability of the data for present and future generations. Two fundamental pillars support this ambitious goal: The external peer review required for acceptance of all archived data submissions; and the PDS Standards for data and metadata formatting and completeness. The PDS external peer review process is at least equivalent to, if not more rigorous than, the journal refereeing process(1). Data reviewers who are field experts but not affiliated with the data preparer, nor involved in the PDS consulting process, are brought in to review documentation and completeness. They are specifically charged to attempt to use the data to perform some scientific investigation (reproducing published results, comparison to correlated observations for consistency, etc.). If the reviewers are not successful, the impediments are documented and the data submission is amended by the preparer until the reviewers are satisfied. This process demonstrates immediate usability of the data. The PDS Standards, and in particular the recently-implemented version based on the PDS4 Information Model, require exhaustive metadata documenting data structure, observing circumstances, provenance, analytical metadata, and so on using the same templates across the entire archive. The associated schematic enforcement of at least minimal requirements for metadata completeness and quality provides a foundation for discoverability, interoperability, and usability of data from disparate sources throughout the archive. Together, the PDS external peer review and the Information Model-based PDS4 standards ensure both quality and usability for data accepted into the PDS archive, for this and future generations of planetary scientists. Reference: (1) Raugh, A. and Bauer, J., PDS Data Sets as Peer-Reviewed References, Poster presented at the 15th Annual Meeting of the Asia Oceania Geosciences Society Meeting, 03-08 June 2018, Honolulu, Hawai’i.

Several studies suggest that magnetic reconnection plays an essential role to generate and accelerate most of the erupting coronal magnetic flux ropes such as coronal mass ejections (CMEs). We explore the connection between magnetic properties (magnetic flux and helicity) of interplanetary coronal mass ejection (ICME) flux-ropes (magnetic clouds [MCs]) and those of associated near-sun CME flux-ropes formed in situ by low corona magnetic reconnection. We identify the progenitor CMEs and their solar sources and derive the source region reconnection flux using the post-eruption arcade (PEA) method. Combining the reconnection flux and the geometrical properties of associated CMEs obtained by forward-modeling, we extract the magnetic properties of CME flux ropes at their source. To measure the magnetic properties of 1 AU ICME we use constant-α force-free cylindrical flux rope model fit to in situ observations and directly from the observed magnetic time series rotated to the cloud frame. We investigate whether a significant difference exists in magnetic properties of ICMEs if their solar source is composed of pre-existing flux-ropes (filaments). This study has significant implications in finding the role of reconnection in the formation of twisted flux ropes during a solar eruptive process that transport solar magnetic flux and helicity into interplanetary space.