This work provides a relative intercalibration of the high-energy proton channels from the Energetic Particle Sensors (EPS) flown on the Geostationary Operational Environmental Satellites (GOES) since 1994 using a technique that depends on features that arise during high solar wind dynamic pressure. Based on observations of solar energetic protons from polar-orbiting and geostationary satellites (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013), solar proton fluxes are isotropic at geostationary orbit during periods of high solar wind dynamic pressure (P dyn > 5 − 10 nPa). The observed isotropy results from the solar proton fluxes having rigidities (momenta per unit charge) greater than their geomagnetic cutoffs over the complete energy and angular responses of the satellite-borne detector. (The cutoff in a given direction is the rigidity below which an interplanetary particle cannot reach that location.) Under these conditions, we determine the relative responses of the EPS flown on GOES 8 through 15. These detectors are widely used for alerts of the radiation hazard posed to spacecraft and humans by solar energetic particle events; therefore, it is important to know their relative responses. The results of this low-scatter intercalibration analysis show that the relative responses agree to 20% or better (sometimes better than 1%). The effect of such relative calibration differences on the derived integral fluxes used by NOAA for its real-time solar radiation storm alerts is shown to be small (<10%). This method can be used to intercalibrate solar proton detectors of different design if their broad energy response functions are carefully accounted for.

Immediately following the breakup of the 2005 Arctic spring stratospheric vortex, a tropical air mass, characterized by low potential vorticity (PV) and high nitrous oxide (N₂O), was advected poleward and became trapped in the easterly summer polar vortex. This feature, known as a "Frozen-In Anticyclone (FrIAC)", was observed in Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) data to span the potential temperature range from ~580 to 1100 K (~25 to 40 km altitude) and to persist from late March to late August 2005. This study compares MLS N₂O observations with simulations from the Global Modeling Initiative (GMI) chemistry and transport model, the GEOS-5/MERRA Replay model, and the Van Leer Icosahedral Triangular Advection (VITA) isentropic transport model to elucidate the processes involved in the lifecycle of the FrIAC, which is here divided into three distinct phases. During the "spin-up phase" (March to early April), strong poleward flow resulted in a tight isolated anticyclonic vortex at ~70–90° N, marked with elevated N₂O. GMI, Replay, and VITA all reliably simulated the spin-up of the FrIAC, although the GMI and Replay peak N₂O values were too low. The FrIAC became trapped in the developing summer easterly flow and circulated around the polar region during the "anticyclonic phase" (early April to the end of May). During this phase, the FrIAC crossed directly over the pole between 7 and 14 April. The VITA and Replay simulations transported the N₂O anomaly intact during this crossing, in agreement with MLS, but unrealistic dispersion of the anomaly occurred in the GMI simulation due to excessive numerical mixing of the polar cap. The vortex associated with the FrIAC was apparently resistant to the weak vertical shear during the anticyclonic phase, and it thereby protected the embedded N₂O anomaly from stretching. The vortex decayed in late May due to diabatic processes, leaving the N₂O anomaly exposed to horizontal and vertical wind shears during the "shearing phase" (June to August). The observed lifetime of the FrIAC during this phase is consistent with timescales calculated from the ambient horizontal and vertical wind shear. Replay maintained the horizontal structure of the N₂O anomaly similar to MLS well into August. Isentropic simulations using VITA also captured the horizontal structure of the FrIAC during this phase, but small-scale structures maintained by VITA are problematic and show that important mixing processes are absent from this single-level simulation

Immediately following the breakup of the 2005 Arctic spring stratospheric vortex, a tropical air mass, characterized by low potential vorticity (PV) and high nitrous oxide (N₂O), was advected poleward and became trapped in the easterly summer polar vortex. This feature, known as a "Frozen-In Anticyclone (FrIAC)", was observed in Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) data to span the potential temperature range from ~580 to 1100 K (~25 to 40 km altitude) and to persist from late March to late August 2005. This study compares MLS N₂O observations with simulations from the Global Modeling Initiative (GMI) chemistry and transport model, the GEOS-5/MERRA Replay model, and the Van Leer Icosahedral Triangular Advection (VITA) isentropic transport model to elucidate the processes involved in the lifecycle of the FrIAC, which is here divided into three distinct phases. During the "spin-up phase" (March to early April), strong poleward flow resulted in a tight isolated anticyclonic vortex at ~70–90° N, marked with elevated N₂O. GMI, Replay, and VITA all reliably simulated the spin-up of the FrIAC, although the GMI and Replay peak N₂O values were too low. The FrIAC became trapped in the developing summer easterly flow and circulated around the polar region during the "anticyclonic phase" (early April to the end of May). During this phase, the FrIAC crossed directly over the pole between the 7 and 14 April. The VITA and Replay simulations transported the N₂O anomaly intact during this crossing, in agreement with MLS, but unrealistic dispersion of the anomaly occurred in the GMI simulation due to excessive numerical mixing of the polar cap. The vortex associated with the FrIAC was apparently resistant to the weak vertical shear during the anticyclonic phase, and it thereby protected the embedded N₂O anomaly from stretching. The vortex decayed in late May due to diabatic processes, leaving the N₂O anomaly exposed to horizontal and vertical wind shears during the "shearing phase" (June to August). The observed lifetime of the FrIAC during this phase is consistent with timescales calculated from the ambient horizontal and vertical wind shear. Replay maintained the horizontal structure of the N₂O anomaly similar to MLS well into August. The VITA simulation also captured the horizontal structure of the FrIAC during this phase, but VITA eventually developed fine-scale N₂O structure not observed in MLS data

Abstract-While the past decade has seen a widespread adoption of power electronics curriculum at various university electrical engineering programs, authentic laboratory experiences for students remains to be a challenge for inclusion in the programs. This paper discusses a modular power electronics learning platform called PEGO. PEGO consists of self-contained two terminal modular building blocks for power converters which may be cascaded stage by stage to achieve an overall functional objective. The system has been developed to complement a lecture based design oriented theory course in power electronics. The theory course and the laboratory platform are designed to lead to a system level project experience for the students. A primitive UPS system consisting of a battery charger, high frequency isolated dc-dc converter and a low frequency pulse width modulated inverter is illustrated as a candidate project experience. A detailed description of the system along with sample results from the hardware/software exercises are presented in the paper.