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1. Comparison of Van Allen Probes radiation belt proton data with test particle simulation for the 17 March 2015 storm: PROTON LOSS

   https://doi.org/10.1002/2016JA023333  

   Engel, M. A. ; Kress, B. T. ; Hudson, M. K. ; Selesnick, R. S. ( November 2016 , Journal of Geophysical Research: Space Physics)
2. The extent of soil loss across the US Corn Belt

   https://doi.org/10.1073/pnas.1922375118  

   Thaler, Evan A. ; Larsen, Isaac J. ; Yu, Qian ( February 2021 , Proceedings of the National Academy of Sciences)

   Soil erosion in agricultural landscapes reduces crop yields, leads to loss of ecosystem services, and influences the global carbon cycle. Despite decades of soil erosion research, the magnitude of historical soil loss remains poorly quantified across large agricultural regions because preagricultural soil data are rare, and it is challenging to extrapolate local-scale erosion observations across time and space. Here we focus on the Corn Belt of the midwestern United States and use a remote-sensing method to map areas in agricultural fields that have no remaining organic carbon-rich A-horizon. We use satellite and LiDAR data to develop a relationship between A-horizon loss and topographic curvature and then use topographic data to scale-up soil loss predictions across 3.9 × 10⁵km²of the Corn Belt. Our results indicate that 35 ± 11% of the cultivated area has lost A-horizon soil and that prior estimates of soil degradation from soil survey-based methods have significantly underestimated A-horizon soil loss. Convex hilltops throughout the region are often completely denuded of A-horizon soil. The association between soil loss and convex topography indicates that tillage-induced erosion is an important driver of soil loss, yet tillage erosion is not simulated in models used to assess nationwide soil loss trends in the United States. We estimate that A-horizon loss decreases crop yields by 6 ± 2%, causing $2.8 ± $0.9 billion in annual economic losses. Regionally, we estimate 1.4 ± 0.5 Pg of carbon have been removed from hillslopes by erosion of the A-horizon, much of which likely remains buried in depositional areas within the fields.

    

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3. Modeling the Effects of Drift Orbit Bifurcation on the Magnetopause Shadowing Loss of Radiation Belt Electrons

   https://doi.org/10.1029/2023GL106359  

   Huang, Jinbei ; Lyu, Xingzhi ; Tu, Weichao ; Albert, Jay_M ; Lee, Sang‐Yun ( December 2023 , Geophysical Research Letters)

   Last closed drift shell (LCDS) has been identified as a crucial parameter for investigating the magnetopause shadowing loss of radiation belt electrons. However, drift orbit bifurcation (DOB) effects have not been physically incorporated into the LCDS calculation. Here we calculate event‐specific LCDS using different approaches to dealing with the DOB effects, that is, tracing field lines ignoring DOB, tracing test particles rejecting field lines with DOB, and tracing particles including field lines with DOB, and then incorporate them into a radial diffusion model to simulate the fast electron dropout observed by Van Allen Probes in May 2017. The model effectively captures the fast dropout at highL*and exhibits the best agreement with data when LCDS is calculated by tracing test particles with DOB more physically included. This study represents the first quantitative modeling of the DOB effects on radiation belt magnetopause shadowing loss via a more physical specification of LCDS.

    

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4. Simultaneous event‐specific estimates of transport, loss, and source rates for relativistic outer radiation belt electrons

   https://doi.org/10.1002/2016JA023093  

   Schiller, Q. ; Tu, W. ; Ali, A. F. ; Li, X. ; Godinez, H. C. ; Turner, D. L. ; Morley, S. K. ; Henderson, M. G. ( March 2017 , Journal of Geophysical Research: Space Physics)
5. Differentiating Between Simultaneous Loss Drivers in Earth's Outer Radiation Belt: Multi‐Dimensional Phase Space Density Analysis

   https://doi.org/10.1029/2023GL106162  

   Staples, F_A ; Ma, Q. ; Kellerman, A. ; Rae, I_J ; Forsyth, C. ; Sandhu, J_K ; Bortnik, J. ( December 2023 , Geophysical Research Letters)

   We analyzed the contribution of electromagnetic ion cyclotron (EMIC) wave driven electron loss to a flux dropout event in September 2017. The evolution of electron phase space density (PSD) through the dropout showed the formation of a radially peaked PSD profile as electrons were lost at highL*, resembling distributions created by magnetopause shadowing. By comparing 2D Fokker Planck simulations of pitch angle diffusion to the observed change in PSD, we found that theμandKof electron loss aligned with maximum scattering rates at dropout onset. We conclude that, during this dropout event, EMIC waves produced substantial electron loss. Because pitch angle diffusion occurred on closed drift paths near the last closed drift shell, no radial PSD minimum was observed. Therefore, the radial PSD gradients resembled solely magnetopause shadowing loss, even though the local pitch angle scattering produced electron losses of several orders of magnitude of the PSD.

    

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