Observations of downwelling far-infrared emission at Table Mountain California made by the FIRST instrument

AbstractThe Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument measured downwelling far-infrared (far-IR) and mid-infrared (mid-IR) atmospheric spectra from 200 to 800cm−1 at Table Mountain, California (elevation 2285m). Spectra were recorded during a field campaign conducted in early autumn 2012, subsequent to a detailed laboratory calibration of the instrument. Radiosondes launched coincident with the FIRST observations provide temperature and water vapor profiles for model simulation of the measured spectra. Results from the driest day of the campaign (October 19, with less than 3mm precipitable water) are presented here. Considerable spectral development is observed between 400 and 600cm−1. Over 90% of the measured radiance in this interval originates within 2.8km of the surface. The existence of temperature inversions close to the surface necessitates atmospheric layer thicknesses as fine as 10m in the radiative transfer model calculations. A detailed assessment of the uncertainties in the FIRST measurements and in the model calculations shows that the measured radiances agree with the model radiance calculations to within their combined uncertainties. The uncertainties in modeled radiance are shown to be larger than the measurement uncertainties. Overall, the largest source of uncertainty is in the water vapor concentration used in the radiative transfer calculations. Proposed new instruments with markedly higher measurement accuracy than FIRST will be able to measure the far-IR spectrum to much greater accuracy than it can be computed. As such, accurate direct measurements of the far-IR, and not solely calculations, are essential to the assessment of climate change

Prediction of buried mine-like target radar signatures using wideband electromagnetic modeling

ABSTRACT Current ground penetrating radars (GPR) have been tested for land mine detection, but they have generally been costly and have poor performance. Comprehensive modeling and experimentation must be done to predict the electromagnetic (EM) signatures of mines to access the effect of clutter on the EM signature of the mine, and to understand the merit and limitations of using radar for various mine detection scenarios. This modeling can provide a basis for advanced radar design and detection techniques leading to superior performance. Lawrence Livermore National Laboratory (LLNL) has developed a radar technology that when combined with comprehensive modeling and detection methodologies could be the basis of an advanced mine detection system. Micropower Impulse Radar (MIR) technology exhibits a combination of properties, including wideband operation, extremely low power consumption, extremely small size and low cost, array configurability, and noise encoded pulse generation. LLNL is in the process of developing an "optimal" processing algorithm to use with the MIR sensor. In this paper, we use classical numerical models to obtain the signature of mine-like targets and examine the effect of surface roughness on the reconstructed signals. These results are then qualitatively compared to experimental data

Ionospheric E-Region Response to Solar-Geomagnetic Storms Observed by TIMED/SABER and Application to IRI Storm-Model Development

The large thermospheric infrared radiance enhancements observed from the TIMED/SABER experiment during recent solar storms provide an exciting opportunity to study the influence of solar-geomagnetic disturbances on the upper atmosphere and ionosphere. In particular, nighttime enhancements of 4.3 um emission, due to vibrational excitation and radiative emission by NO+, provide an excellent proxy to study and analyze the response of the ionospheric E-region to auroral electron dosing and storm-time enhancements to the E-region electron density. In this paper we give a status report of on-going work on model and data analysis methodologies of deriving NO+ 4.3 um volume emission rates, a proxy for the storm-time E-region response, and the approach for deriving an empirical storm-time correction to International Reference Ionosphere (IRI) E-region NO+ and electron densities

Atomic oxygen in the mesosphere and lower thermosphere derived from SABER : Algorithm theoretical basis and measurement uncertainty

Peer reviewedPublisher PD

The Spectroscopic Foundation of Radiative Forcing of Climate by Carbon Dioxide

No abstract availabl

Global Conservation Priorities for Marine Turtles

Where conservation resources are limited and conservation targets are diverse, robust yet flexible priority-setting frameworks are vital. Priority-setting is especially important for geographically widespread species with distinct populations subject to multiple threats that operate on different spatial and temporal scales. Marine turtles are widely distributed and exhibit intra-specific variations in population sizes and trends, as well as reproduction and morphology. However, current global extinction risk assessment frameworks do not assess conservation status of spatially and biologically distinct marine turtle Regional Management Units (RMUs), and thus do not capture variations in population trends, impacts of threats, or necessary conservation actions across individual populations. To address this issue, we developed a new assessment framework that allowed us to evaluate, compare and organize marine turtle RMUs according to status and threats criteria. Because conservation priorities can vary widely (i.e. from avoiding imminent extinction to maintaining long-term monitoring efforts) we developed a “conservation priorities portfolio” system using categories of paired risk and threats scores for all RMUs (n = 58). We performed these assessments and rankings globally, by species, by ocean basin, and by recognized geopolitical bodies to identify patterns in risk, threats, and data gaps at different scales. This process resulted in characterization of risk and threats to all marine turtle RMUs, including identification of the world's 11 most endangered marine turtle RMUs based on highest risk and threats scores. This system also highlighted important gaps in available information that is crucial for accurate conservation assessments. Overall, this priority-setting framework can provide guidance for research and conservation priorities at multiple relevant scales, and should serve as a model for conservation status assessments and priority-setting for widespread, long-lived taxa