Eliza S. Bradley

Cloud shading and fog drip influence the metabolism of a coastal pine ecosystem

Assessing the ecological importance of clouds has substantial implications for our basic understanding of ecosystems and for predicting how they will respond to a changing climate. This study was conducted in a coastal Bishop pine forest ecosystem that experiences regular cycles of stratus cloud cover and inundation in summer. Our objective was to understand how these clouds impact ecosystem metabolism by contrasting two sites along a gradient of summer stratus cover. The site that was under cloud cover ~15% more of the summer daytime hours had lower air temperatures and evaporation rates, higher soil moisture content, and received more frequent fog drip inputs than the site with less cloud cover. These cloud-driven differences in environmental conditions translated into large differences in plant and microbial activity. Pine trees at the site with greater cloud cover exhibited less water stress in summer, larger basal area growth, and greater rates of sap velocity. The difference in basal area growth between the two sites was largely due to summer growth. Microbial metabolism was highly responsive to fog drip, illustrated by an observed ~3-fold increase in microbial biomass C with increasing summer fog drip. In addition, the site with more cloud cover had greater total soil respiration and a larger fractional contribution from heterotrophic sources. We conclude that clouds are important to the ecological functioning of these coastal forests, providing summer shading and cooling that relieve pine and microbial drought stress as well as regular moisture inputs that elevate plant and microbial metabolism. These findings are important for understanding how these and other seasonally dry coastal ecosystems will respond to predicted changes in stratus cover, rainfall, and temperature.

Design of an image analysis website for phenological and meteorological monitoring

Web camera image databases and web-based services can be valuable components for a variety of modelling applications, but are still areas of relatively new exploration. Investigating design and information flow for an online image archive and analysis site for plant phenology and meteorological research has broader relevance to considerations of interoperability and website features. Currently, numerous online weather cameras provide images, but have no or limited-utility archives and do not support quantitative image analysis. We describe the design and implementation of a website (http://zulu.geog.ucsb.edu/Data/camera.html) that both provides different display options for archived image review, as well as the ability to chart time-series values extracted for user-specified regions of interest. This interface is distinguished by content-enabled charts with the ability to click on data points and directly access the corresponding image for reference purposes. A linked website to the meteorological data from the camera station further extends the potential for exploratory analysis and pedagogical utility. Online quantification of the color change related to plant senescence and insolation impacts due to cloud cover are demonstrated. We conclude that dynamic web pages are a powerful and useful tool for adding educational and scientific value to repeat digital photography systems.

Linking Physical Geography Education and Research through the Development of an Environmental Sensing Network and Project-Based Learning.

Geographic education is more effective when students actively participate by developing hypotheses, designing experiments, collecting and analyzing data, and discussing results. We describe an innovative pedagogical approach, in which students learn physical geography concepts by analyzing environmental data collected in contrasting environments in Santa Barbara County, CA. The major components of this approach include a local network of micrometeorology stations (the Innovative Datasets for Environmental Analysis by Students (IDEAS network)), student field trips, a web portal (www.geog.ucsb.edu/ideas) and analysis tools which support student education and research. Examples of student work, graded rubrics, course evaluation scores, and instructor observations demonstrate the effectiveness of this approach. The most serious limitation is the high cost of equipment given the low number of students initially involved, a weakness that can be addressed through expanded use of this facility by other physical geography classes and institutions, facilitated by the IDEAS website, and increased enrollment in existing classes.

Multi-Scale Sensor Fusion With an Online Application: Integrating GOES, MODIS, and Webcam Imagery for Environmental Monitoring

Webcam and satellite imagery are integral sensor web components, but there are few websites that directly synthesize these products. Additionally, websites as a means for reviewing multiple images in an organized way and for analyzing time-series imagery have not been fully explored. This paper describes how web applications can facilitate review of image archives for multi-scale sensor data fusion, with a test case of an automatic panning camera at the highest peak on Santa Cruz Island (in Channel Islands National Park off the Santa Barbara, CA coast) and MODIS and GOES-11 satellite imagery. We developed the application PanOpt (http://zulu.geog.ucsb.edu/panopt/index.html) for filtering this image database and outputting selected images as a static matrix or as an animation. On-demand product generation includes time-series charts and scatter plots of image metrics for regions of interest, with data markers linked to views of corresponding satellite and camera imagery via event-based web scripting. This is useful not only for exploratory analysis but is well suited for pedagogical applications and imparting a greater synoptic understanding of environmental phenomena. Demonstration of this websites utility includes multi-modal characterization of clouds as well as ground- and satellite-based plant phenology time-series. With this tool, the quantitative and qualitative aspects of image exploration are synergistic, making it easier to discern underlying trends and anomalies and to identify directions for further analysis.

Point source emissions mapping using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) measures reflected solar radiation in the shortwave infrared and has been used to map methane (CH4) using both a radiative transfer technique [1] and a band ratio method [2]. However, these methods are best suited to water bodies with high sunglint and are not well suited for terrestrial scenes. In this study, a cluster-tuned matched filter algorithm originally developed by Funk et al. [3] for synthetic thermal infrared data was used for gas plume detection over more heterogeneous backgrounds. This approach permits mapping of CH4, CO2 (carbon dioxide), and N2O (nitrous oxide) trace gas emissions in multiple AVIRIS scenes for terrestrial and marine targets. At the Coal Oil Point marine seeps offshore of Santa Barbara, CA, strong CH4 anomalies were detected that closely resemble results obtained using the band ratio index. CO2 anomalies were mapped for a fossil-fuel power plant, while multiple N2O and CH4 anomalies were present at the Hyperion wastewater treatment facility in Los Angeles, CA. Nearby, smaller CH4 anomalies were also detected immediately downwind of hydrocarbon storage tanks and centered on a flaring stack at the Inglewood Gas Plant. Improving these detection methods might permit gas detection over large search areas, e.g. identifying fugitive CH4 emissions from damaged natural gas pipelines or hydraulic fracturing. Further, this technique could be applied to other trace gasses with distinct absorption features and to data from planned instruments such as AVIRISng, the NEON Airborne Observation Platform (AOP), and the visible-shortwave infrared (VSWIR) sensor on the proposed HyspIRI satellite.