Normalized algorithm for mapping and dating forest disturbances and regrowth for the United States

Forest disturbances such as harvesting, wildfire and insect infestation are critical ecosystem processes affecting the carbon cycle. Because carbon dynamics are related to time since disturbance, forest stand age that can be used as a surrogate for major clear-cut/fire disturbance information has recently been recognized as an important input to forest carbon cycle models for improving prediction accuracy. In this study, forest disturbances in the USA for the period of ∼1990–2000 were mapped using 400+ pairs of re-sampled Landsat TM/ETM scenes in 500m resolution, which were provided by the Landsat Ecosystem Disturbance Adaptive Processing System project. The detected disturbances were then separated into two five-year age groups, facilitated by Forest Inventory and Analysis (FIA) data, which was used to calculate the area of forest regeneration for each county in the USA.     

Pressure-temperature microscopy of coal liquefaction

A pressure-temperature microscopy system (PTM) has been developed for obtaining observations on coals and heavy hydrocarbons at elevated temperatures and hudrogen pressures commonly used in the hydroprocessing of coal, coal liquids, and petroleum residua. A Pittsburgh #8 seam coal, from near New Eagle in Washington County located south of Pittsburgh, Penna., was extensively characterized by petrographic analysis, proximate and ultimate analysis, Gieseler plastometer, and Ruhr dilatometry as well as data on grindability, ash characteristics, and oxidation properties. Novel direct microscopic observations at elevated temperatures and pressures with catalysts give observable changes in phase transition behavior of coal. Direct microscopic observations of fresh vitrain particles at elevated temperature and high nitrogen pressure in the presence of a tin chloride catalyst show plastic deformation. Upon replacement of nitrogen by pressurized hydrogen, individual vitrain particles are observed to liquefy in the presence of molten tin. After liquefaction, further temperature increase at 1950 psig hydrogen results in the formation of mesophase and the segregation of the molten tin.Pressure-temperature microscopy is also presented on the liquefaction behavior of a solvent-refined coal (SRC) from Wilsonville, Ala. Additional pressure-temperature microscopy is presented on the tin-catalyzed co-liquefaction behavior of the solvent-refined coal with the Pittsburgh #8 seam vitrain. The pressure-temperature microscopy of the liquefaction experiments and mesophase development have been video recorded and are available for viewing.     

Near real-time geoprocessing on the grid: A scalable approach to road traffic monitoring

The geospatial sensor web is set to revolutionise real-time geospatial applications by making up-to-date spatially and temporally referenced data relating to real-world phenomena ubiquitously available. The uptake of sensor web technologies is largely being driven by the recent introduction of the OpenGIS Sensor Web Enablement framework, a standardisation initiative that defines a set of web service interfaces and encodings to task and query geospatial sensors in near real time. However, live geospatial sensors are capable of producing vast quantities of data over a short time period, which presents a large, fluctuating and ongoing processing requirement that is difficult to adequately provide with the necessary computational resources. Grid computing appears to offer a promising solution to this problem but its usage thus far has primarily been restricted to processing static as opposed to real-time data sets. A new approach is presented in this work whereby geospatial data streams are processed on grid computing resources. This is achieved by submitting ongoing processing jobs to the grid that continually poll sensor data repositories using relevant OpenGIS standards. To evaluate this approach a road-traffic monitoring application was developed to process streams of GPS observations from a fleet of vehicles. Specifically, a Bayesian map-matching algorithm is performed that matches each GPS observation to a link on the road network. The results show that over 90% of observations were matched correctly and that the adopted approach is capable of achieving timely results for a linear time geoprocessing operation performed every 60 seconds. However, testing in a production grid environment highlighted some scalability and efficiency problems. Open Geospatial Consortium (OGC) data services were found to present an IO bottleneck and the adopted job submission method was found to be inefficient. Consequently, a number of recommendations are made regarding the grid job-scheduling mechanism, shortcomings in the OGC Web Processing Service specification and IO bottlenecks in OGC data services.     

Global tsunami deposits database

The National Geophysical Data Center and co-located World Data Center for Geophysics and Marine Geology provide integrated access to historical tsunami event, deposit, and proxy data. Historical events are important for understanding the frequency and intensity of relatively recent tsunamis. Deposit data collected during post-tsunami field surveys provide information on tsunami erosion, sedimentation, flow depths, inundation, and run-up. Deposit data from prehistoric tsunami events extend the record to pre-recorded times, constrain tsunami recurrence intervals, and estimate the minimum magnitude of tsunami inundation. Proxies indicate that an event capable of producing a tsunami occurred, but are not direct evidence of a tsunami. All of these data are used to develop tsunami hazard assessments, provide guidance to warning centers, validate models, inform community preparedness efforts, and educate the public about tsunami risks.     

A Service Oriented Geoprocessing System for Real‐Time Road Traffic Monitoring

The emergence of the Sensor Web has paved the way for a new set of innovative software applications that exploit the enhanced availability of real‐time information. This article describes one such application built from Sensor Web components that aggregates GPS track data from a fleet of vehicles to provide an overview of road traffic congestion at the city scale. The application embodies a Service Oriented Architecture; web service components are used to archive and pre‐process incoming sensor observations, to encapsulate a horizontally partitioned spatial database that performs geoprocessing, and to disseminate results to client applications. Our results confirm that floating car data can provide an accurate depiction of current road traffic conditions. The presented solution uses Open Geospatial Consortium web services where possible and serves to highlight the difficulties inherent in achieving horizontal database scalability in sensor based geoprocessing systems.     

Soil moisture response to white ash mortality following emerald ash borer invasion

Emerald ash borer (EAB) (Agrilus planipennis Fairmaire), an invasive forest insect first identified in southeastern Michigan in 2002, is established in at least 32 US states and three Canadian provinces. Ash (Fraxinus spp.) mortality rates in some forested areas exceed 90%, but to date, little is known about the potential effects of EAB-caused ash mortality on hydrological processes. More broadly, there is a need for information on the timing and magnitude of soil moisture response to species-specific mortality of overstory vegetation in deciduous forest systems. Soil moisture was examined in 28 forested sites where 0–100% of the white ash basal area (Fraxinus americana L.) was killed by EAB. Synoptic measurements of near-surface (0–6 cm depth) soil moisture were collected from 112 plots (18 m radius) within the sites. Three plots were also instrumented with soil moisture sensors at 10 and 25 cm depth to log hourly measurements from May to October. Synoptic data showing white ash mortality and soil moisture were positively correlated in the 34 plots with ≥?5% mortality (by total basal area). In the intensively monitored plots, volumetric soil moisture declined from 37 to 16% between July and September where white ash mortality was low (0.6% of basal area killed), but remained near field capacity (~?30%) throughout the monitoring period in the high mortality plot (8.6% of basal area killed), meriting further investigation to assess effects of white ash mortality on evapotranspiration and soil moisture dynamics in heterogeneous upland forests. Altered soil moisture may have implications for regrowth dynamics, infiltration/runoff partitioning, and nutrient cycling, but additional study to quantify the extent and duration of EAB-related ash mortality on hydrology at the plot and watershed scale is necessary.     

Polarization of solar active regions at 9.5 mm wavelength

A study of the circular polarization structure of solar active regions has been made from data obtained at 9.5 mm wavelength, using the 85 ft reflector and polarimeter at the Naval Research Laboratory Maryland Point Observatory. The angular resolution of the telescope at this wavelength is 1.6. All important active regions observed at 9.5 mm are bipolar in nature, the degree of polarization is about the same for both right and left circular components and it ranges up to about 4%. These oppositely polarized components correspond with the Mt. Wilson magnetic regions of opposite polarity; the line of zero polarization delineates clearly the neutral line between the regions of opposite polarity on magnetograms. Unipolar regions in magnetograms also show up as unipolar regions at 9.5 mm. Magnetic fields as low as 5–10 G on magnetograms manifest as distinctly polarized regions on 9.5 mm maps. A line of zero polarization seems to delineate the extent of absorption features observed at 9.5 mm in coincidence with H dark filaments.     

Brightness distributions of the Sun at 33 and 37 GHz

The brightness distributions of the Sun were observed at 33 and 37 GHz. Maximum limb brightening of about 10% was observed at both frequencies.