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Hecht, James

Publications and source records attributed to Hecht, James.

GOES-R L1b Readiness Implementation and Management Plan

A complement of Readiness, Implementation and Management Plans (RIMPs) to facilitate management of post-launch product test activities for the official Geostationary Operational Environmental Satellite (GOES-R) Level 1b (L1b) products have been developed and documented. Separate plans have been created for each of the GOES-R sensors including: the Advanced Baseline Imager (ABI), the Extreme ultraviolet and X-ray Irradiance Sensors (EXIS), Geostationary Lightning Mapper (GLM), GOES-R Magnetometer (MAG), the Space Environment In-Situ Suite (SEISS), and the Solar Ultraviolet Imager (SUVI). The GOES-R program has implemented these RIMPs in order to address the full scope of CalVal activities required for a successful demonstration of GOES-R L1b data product quality throughout the three validation stages: Beta, Provisional and Full Validation. For each product maturity level, the RIMPs include specific performance criteria and required artifacts that provide evidence a given validation stage has been reached, the timing when each stage will be complete, a description of every applicable Post-Launch Product Test (PLPT), roles and responsibilities of personnel, upstream dependencies, and analysis methods and tools to be employed during validation. Instrument level Post-Launch Tests (PLTs) are also referenced and apply primarily to functional check-out of the instruments.

Validation Readiness↗

Lower Thermospheric Composition Studies in the Auroral Zone

This TIMED/CEDAR grant had two major objectives. The GUVI instrument on TIMED should routinely produces maps of the flux of energetic particles and their average energy. However, while those data will be available soon there were no plans to routinely produce the O/N2 ratio in the auroral. Ground-based photometric techniques have been available for years which routinely measure all three quantities in the auroral zone. The first objective of the previous proposal was to use these ground-based techniques to provide some validation for the routine measure of average energy. The second objective was to use the ground-based to data to validate GUVI algorithms for the measure of O/N2 in the auroral zone. We have made some progress to these goals while we await the release of the properly precessed GUVI data. For now these objectives are being addressed by making use of algorithms by one of us (Doug Strickland of CPI) that are being used for specific GUVI level 1B data sets that contain data coincident with the groundbased measurements. Also we have collected ground-based data from two Alaska sites and they are available on our web site and on the CEDAR website. The details of the progress we have made are discussed.

Hecht, James↗

The Link Between UV Extinction and Infrared Cirrus

Low resolution spectra from the International Ultraviolet Explorer satellite were used to derive ultraviolet extinction curves for stars in four clusters away from the galactic plane. The extinction in three of the clusters is very similar to the general interstellar curve defined by Seaton. Stars in the fourth region, near the Rho Ophiuci dark cloud, have extinction curves that are characterized by a small "linear" term component. The star BD +36 deg 781 is unique amongst the 20 stars observed in that it shows evidence for extinction by diamond grains near 1700 angstroms. We used data from the final release of the IRAS Sky Survey Atlas (ISSA) to determine the 60 micron to 100 micron intensity ratio for the infrared cirrus. The ISSA data, which have been corrected for zodiacal light, gave intensity ratios that are more robust and self-consistent than for other data sets that we used. When the infrared and ultraviolet data are combined, we see a general trend for low values of the ultraviolet "linear term" (al) to correlate with high values of 60 micron/100 micron ratio. This implies that, in regions where the average dust temperature is hotter (high 60 micron/100 micron ratio), there is a relative absence of the small silicate grains that are responsible for the ultraviolet linear term. However, the new data do not bear out our earlier contention that the 60 micron and 100 micron emissions are poorly correlated spatially in regions where the 60 micron/100 micron ratio is low. Only NGC 1647 shows this result. It may be that the different dust types are particularly poorly mixed in this area.

Hackwell, John A.↗