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McKinney, M. M.; Mitchell, J.; Thomson, S. I.(
, Journal of the Atmospheric Sciences)
Abstract Saturn’s largest moon, Titan, has an Earth-like volatile cycle, but with methane playing the role of water and surface liquid reservoirs geographically isolated at high latitudes. We recreate Titan’s characteristic dry hydroclimate at the equator of an Earth-like climate model without seasons and with water as the condensable by varying a small set of planetary parameters. We use three observationally motivated criteria for Titan-like conditions at the equator: 1) the peak in surface specific humidity is not at the equator, despite it having the warmest annual-mean temperatures; 2) the vertical profile of specific humidity in the equatorial column ismore »nearly constant through the lower troposphere; and 3) the relative humidity near the surface at the equator is significantly lower than saturation (lower than 60%). We find that simply reducing the available water at the equator does not fully reproduce Titan-like conditions. We additionally vary the rotation period and volatility of water to mimic Titan’s slower rotation and more abundant methane vapor. Longer rotation periods coupled with a dry equatorial surface meet fewer of the Titan-like criteria than equivalent experiments with shorter rotation periods. Experiments with higher volatility of water meet more criteria than those with lower volatility, with some of those with the highest volatility meeting all three, demonstrating that an Earth-like planet can display Titan-like climatology by changing only a few physical parameters.« less
Free, publicly-accessible full text available July 22, 2023
A lasting impact of the COVID-19 global pandemic likely is the permanent inclusion of online learning in K–12. The rapid move to online learning left many teachers, parents, and students pining for in-person learning and highlighted major gaps in the online resources necessary for fully remote K–12 learning. But it also underscored considerable strengths of online formats for flexible learning and instruction—particularly as district capacities expanded and familiarity with online instruction increased. Many administrators now envision a permanent end to unplanned school closures (goodbye, snow days!) and long-term support for (at least intermittent) online learning. But what does continued onlinemore »instruction mean for science learning, where hands-on learning is central to students’ developing skills and knowledge? Science educators implementing online instruction have faced myriad challenges, including providing effective feedback and guidance while students engaged in more independent work. We greatly respect and admire the passion and dedication that science teachers have invested in finding creative ways to implement science inquiry during online pandemic instruction. As we move beyond “emergency” remote instruction and build on shared experiences with online science teaching, it is an ideal time to rethink science inquiry online and to collectively pursue new approaches to authentic science instruction with online resources.« less
Free, publicly-accessible full text available April 1, 2023
Getachew, T.; McComas, D. J.; Joyce, C. J.; Palmerio, E.; Christian, E. R.; Cohen, C. M.; Desai, M. I.; Giacalone, J.; Hill, M. E.; Matthaeus, W. H.; et al(
, The Astrophysical Journal)
Abstract In this paper we examine a low-energy solar energetic particle (SEP) event observed by IS⊙IS’s Energetic Particle Instrument-Low (EPI-Lo) inside 0.18 au on 2020 September 30. This small SEP event has a very interesting time profile and ion composition. Our results show that the maximum energy and peak in intensity are observed mainly along the open radial magnetic field. The event shows velocity dispersion, and strong particle anisotropies are observed throughout the event, showing that more particles are streaming outward from the Sun. We do not see a shock in the in situ plasma or magnetic field data throughoutmore »the event. Heavy ions, such as O and Fe, were detected in addition to protons and 4He, but without significant enhancements in 3He or energetic electrons. Our analysis shows that this event is associated with a slow streamer blowout coronal mass ejection (SBO-CME), and the signatures of this small CME event are consistent with those typical of larger CME events. The time–intensity profile of this event shows that the Parker Solar Probe encountered the western flank of the SBO-CME. The anisotropic and dispersive nature of this event in a shockless local plasma gives indications that these particles are most likely accelerated remotely near the Sun by a weak shock or compression wave ahead of the SBO-CME. This event may represent direct observations of the source of the low-energy SEP seed particle population.« less
Free, publicly-accessible full text available February 1, 2023
