Impact of Blackbody Warm-Up Cool-Down Cycle on the Calibration of Aqua MODIS and S-NPP VIIRS Thermal Emissive Bands

This paper evaluates the calibration quality during the blackbody (BB) warm-up cool-down cycle for thermal emissive bands onboard Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) and Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS). This evaluation utilizes data from Aqua MODIS Collection 6 Level-1B products and VIIRS Sensor Data Records in 6-min granule format provided by the NASA Land Science Investigator-led Processing System. Nearly simultaneous hyperspectral measurements from the Aqua Atmospheric Infrared Sounder (AIRS) and the S-NPP Cross-track Infrared Sounder (CrIS) are used as references for MODIS and VIIRS, respectively. Each AIRS footprint of 13.5 km is co-located with multiple MODIS pixels while each CrIS field of view of 14 km is co-located with multiple VIIRS pixels. The corresponding AIRS-simulated MODIS and CrIS-simulated VIIRS radiances are derived by convolutions based on sensor-dependent relative spectral response functions. In this paper, the analysis mainly focuses on the bands that are used in sea surface temperature products. The results show that there is virtually no impact for MODIS bands 22 and 23 and bands 31 and 32 for a BB temperature below 290 K; however, when the BB temperature increases above 290 K, the impact is up to 0.3 K for bands 22 and 23 and 0.05 K for bands 31 and 32, respectively. For VIIRS, BB temperature-dependent drifts are observed in M15 and M16, which can reach 0.15 and 0.1 K, respectively, over the operational BB temperature range and the VIIRS brightness temperature range

JPSS-2 VIIRS Polarization Sensitivity Performance Comparison with Heritage VIIRS Sensors

The Joint Polar Satellite System 2 (JPSS-2) is the follow-on for the Suomi-National Polar-orbiting Partnership (S-NPP) and Joint Polar Satellite System 1 (JPSS-1) missions. These spacecrafts provide critical weather and global climate products to the user community. A primary sensor on both JPSS and S-NPP is the Visible-Infrared Imaging Radiometer Suite (VIIRS) with Earth observations covering the Reflective Solar Band (RSB), Thermal Emissive Band (TEB) and Day Night Band (DNB) spectral regions. The VIIRS Sensor Data Records (SDRs) contain the calibrated Earth observations that are used in Environmental Data Record (EDR) products such as Ocean Color/Chlorophyll (OCC) and Sea Surface Temperature (SST). This SDR calibration is performed using unpolarized sources such as the Solar Diffuser (SD) for the RSBs and an On-Board Calibrator BlackBody (OBCBB) for the TEBs. Therefore, polarized Earth scenes will have radiometric bias errors within the SDRs based on how sensitive VIIRS is to polarized illumination and is corrected in some EDR algorithms. This paper will discuss the JPSS-2 VIIRS polarization characterization methodology, polarization sensitivity results and compare its performance to its predecessors S-NPP and JPSS-1 VIIRS. Optical modifications to the JPSS-2 VIIRS sensor to address heritage polarization sensitivity issues will be discussed

Prelaunch and On-Orbit Electronic Calibration for Earth Observing Instruments

"The Electronic Calibration (Ecal) tests are performed during various stages of instrument development to examinethe linearity of the instrument electronics. During this process, charges with stepwise increments are injected inthe analog electronics circuitry to generate a ramp signal that can be used to characterize any nonlinearities in theelectronics. The prelaunch characterization of MODIS (on the Terra and Aqua platforms) and VIIRS (on SNPP,JPSS-1 and JPSS-2) involved a regular evaluation of the electronics linearity using the Ecal tests. On orbit,the Ecal tests have been regularly performed over the mission for both the MODIS instruments to derive theelectronics gain and linearity. Unlike MODIS, the Ecal tests on the VIIRS instruments are performed on an as-needed basis. To date, no Ecal tests were performed for S-NPP VIIRS on orbit. The VIIRS instrument on JPSS-1(now NOAA 20) was launched on November 18, 2017. An Ecal test was performed to support the instrumentsinitial post-launch performance assessment. Shortly after the first on-orbit emissive band calibration, degradationin the instrument gain was observed for the LWIR bands (M15, M16 and I5). As a part of the investigationrelated to this anomaly, a second Ecal test was performed and results were compared with the prelaunch results.In this paper, we discuss the prelaunch Ecal tests and representative results from MODIS and VIIRS prelaunchcharacterization. Also, discussed are the on-orbit results from the two MODIS instruments as well as from therecently launched VIIRS instrument.

Analysis of JPSS J1 VIIRS Polarization Sensitivity Using the NIST T-SIRCUS

The polarization sensitivity of the Joint Polar Satellite System (JPSS) J1 Visible Infrared Imaging Radiometer Suite (VIIRS) measured pre-launch using a broadband source was observed to be larger than expected for many reflective bands. Ray trace modeling predicted that the observed polarization sensitivity was the result of larger diattenuation at the edges of the focal plane filter spectral bandpass. Additional ground measurements were performed using a monochromatic source (the NIST T-SIRCUS) to input linearly polarized light at a number of wavelengths across the bandpass of two VIIRS spectral bands and two scan angles. This work describes the data processing, analysis, and results derived from the T-SIRCUS measurements, comparing them with broadband measurements. Results have shown that the observed degree of linear polarization, when weighted by the sensor's spectral response function, is generally larger on the edges and smaller in the center of the spectral bandpass, as predicted. However, phase angle changes in the center of the bandpass differ between model and measurement. Integration of the monochromatic polarization sensitivity over wavelength produced results consistent with the broadband source measurements, for all cases considered

Breast Milk Protects Against Gastrointestinal Symptoms in Infants at High Risk for Autism During Early Development.

ObjectivesParents of children with autism spectrum disorders (ASDs) often report gastrointestinal (GI) dysfunction in their children. The objectives of the present study were to determine whether infants at high risk for developing ASD (ie, siblings of children diagnosed as having ASD) show greater prevalence of GI problems and whether this prevalence is associated with diet and age at weaning from breast milk.MethodsUsing questionnaires, diet history and GI problems were tracked prospectively and retrospectively in 57 high-risk infants and for comparison in 114 low-risk infants (infants from families without ASD history).ResultsIn low-risk infants, prevalence of GI symptoms, in aggregate, did not vary with diet or age of weaning. By contrast, high-risk infants with GI symptoms were weaned earlier than those without symptoms (P < 0.04), and high-risk infants showed greater prevalence of GI symptoms, in aggregate, on a no breast milk diet than on an exclusive breast milk diet (P < 0.017). Constipation, in particular, was more prevalent in high-risk infants compared with low-risk infants (P = 0.01), especially on a no breast milk diet (P = 0.002). High-risk infants who completed weaning earlier than 6 months showed greater prevalence of constipation (P = 0.001) and abdominal distress (P = 0.004) than those fully weaned after 6 months.ConclusionsThe greater prevalence of GI symptoms in high-risk infants suggests that GI dysfunction during early infant development may be a part of the ASD endophenotype. Late weaning and exclusive breast milk were associated with protection against GI symptoms in high-risk infants

Breast Milk Protects Against Gastrointestinal Symptoms in Infants at High Risk for Autism During Early Development.

ObjectivesParents of children with autism spectrum disorders (ASDs) often report gastrointestinal (GI) dysfunction in their children. The objectives of the present study were to determine whether infants at high risk for developing ASD (ie, siblings of children diagnosed as having ASD) show greater prevalence of GI problems and whether this prevalence is associated with diet and age at weaning from breast milk.MethodsUsing questionnaires, diet history and GI problems were tracked prospectively and retrospectively in 57 high-risk infants and for comparison in 114 low-risk infants (infants from families without ASD history).ResultsIn low-risk infants, prevalence of GI symptoms, in aggregate, did not vary with diet or age of weaning. By contrast, high-risk infants with GI symptoms were weaned earlier than those without symptoms (P < 0.04), and high-risk infants showed greater prevalence of GI symptoms, in aggregate, on a no breast milk diet than on an exclusive breast milk diet (P < 0.017). Constipation, in particular, was more prevalent in high-risk infants compared with low-risk infants (P = 0.01), especially on a no breast milk diet (P = 0.002). High-risk infants who completed weaning earlier than 6 months showed greater prevalence of constipation (P = 0.001) and abdominal distress (P = 0.004) than those fully weaned after 6 months.ConclusionsThe greater prevalence of GI symptoms in high-risk infants suggests that GI dysfunction during early infant development may be a part of the ASD endophenotype. Late weaning and exclusive breast milk were associated with protection against GI symptoms in high-risk infants

Nitrone [2]rotaxanes: Simultaneous chemical protection and electrochemical activation of a functional group

We report on the use of the hydrogen bond accepting properties of neutral nitrone moieties to prepare benzylic-amide-macrocycle-containing [2]rotaxanes in yields as high as 70 %. X-Ray crystallography shows the presence of up to four intercomponent hydrogen bonds between the amide groups of the macrocycle and the two nitrone groups of the thread. Dynamic 1H NMR studies of the rates of macrocycle pirouetting in nonpolar solutions indicate that amide-nitrone hydrogen bonds are particularly strong, ~1.3 and ~0.2 kcal mol-1 stronger than similar amide-ester and amide-amide interactions, respectively. In addition to polarizing the N-O bond through hydrogen bonding, the rotaxane structure affects the chemistry of the nitrone groups in two significant ways: The intercomponent hydrogen bonding activates the nitrone groups to electrochemical reduction, a one electron reduction of the rotaxane being stablized by a remarkable 400 mV (8.1 kcal mol-1) with respect to the same process in the thread; encapsulation, however, protects the same functional groups from chemical reduction with an external reagent (and slows down electron transfer to and from the electroactive groups in cyclicvoltammetry experiments). Mechanical interlocking with a hydrogen bonding molecular sheath thus provides a route to an encapsulated polarized functional group and radical anions of significant kinetic and thermodynamic stability

Results of SEI Line-Funded Exploratory New Starts Projects

<p>The Software Engineering Institute (SEI) annually undertakes several line-funded exploratory new starts (LENS) projects. These projects serve to (1) support feasibility studies investigating whether further work by the SEI would be of potential benefit and (2) support further exploratory work to determine whether there is sufficient value in eventually funding the feasibility study work as an SEI initiative. Projects are chosen based on their potential to mature and/or transition software engineering practices, develop information that will help in deciding whether further work is worth funding, and set new directions for SEI work. This report describes the LENS projects that were conducted during fiscal year 2012 (October 2011 through September 2012).</p