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Introduction Previous research indicates that traumatized individuals with post-traumatic stress disorder (PTSD) symptoms may show alterations in interpersonal distance regulation that are not evident in traumatized individuals without PTSD symptoms. However, the underlying mechanisms of these alterations are yet to be investigated. Moreover, it is not clear whether altered interpersonal distance regulation is correlated with trauma-related psychopathology. Objectives The current study investigated behavioral and neurophysiological markers of interpersonal distance regulation as predictors of PTSD and anxiety in traumatized firefighters. Methods Twenty-four active-duty firefighters (M = 30.58, SD = 3.62) completed an experimental task that measures comfortable interpersonal distance. During the task, event-related potentials were recorded to assess attentional processing as reflected in the P1 and N1 components. Trauma-related psychopathology was assessed using the Clinician-Administered PTSD Scale and the state version of the State-Trait Anxiety Inventory. Results Participants who did not choose a closer distance towards friends as compared to strangers experienced greater anxiety post-trauma. On a neurophysiological level, participants who showed attentional avoidance towards strangers reported more PTSD symptoms. By contrast, participants who showed hypervigilant attention towards strangers reported greater anxiety. Conclusions The results demonstrate associations between interpersonal distance regulation and psychopathology after trauma, shedding light on the underlying processes of interpersonal distance regulation in anxiety and PTSD. Future studies should re-investigate these associations in a larger sample and explore potential implications for the prevention and treatment of trauma-related psychopathology.

Values of undercatch-corrected liquid-equivalent snowfall rate (S) at a ground site and microwave reflectivity (Z) retrieved using an airborne W-band radar were acquired during overflights. The temperature at the ground site was between −6 and −15 ∘C. At flight level, within clouds containing ice and supercooled liquid water, the temperature was approximately 7 ∘C colder. Additionally, airborne measurements of snow particle imagery were acquired. The images demonstrate that most of the snow particles were rimed, at least at flight level. A relatively small set of S–Z pairs (four) is available from the overflights. Important distinctions between these measurements and those of Pokharel and Vali (2011), who reported S–Z pairs and an S–Z relationship for rimed snow particles, are (1) the fewer S–Z pairs, (2) the method used to acquire S, and (3) the altitude, relative to ground, of the W-band Z retrievals. This analysis corroborates the fact that the S–Z relationship reported in Pokharel and Vali (2011) yields an S – in scenarios with snowfall produced by riming – substantially larger than that derived using an S–Z relationship developed for unrimed snow particles.

The dataset collected during the Radar Snow Experiment (RadSnowExp) presents the first-ever airborne triple-frequency radar observations combined with almost perfectly co-located and coincident airborne microphysical measurements from a single platform, the National Research Council Canada (NRC) Convair-580 aircraft. The potential of this dataset is illustrated using data collected from one flight during an Arctic storm, which covers a wide range of snow habits from pristine ice crystals and low-density aggregates to heavily rimed particles with maximum size exceeding 10 mm. Three different flight segments with well-matched in situ and radar measurements were analyzed, giving a total of 49 min of triple-frequency observations. The in situ particle imagery data for this study include high-resolution imagery from the Cloud Particle Imager (CPI) probe, which allows accurate identification of particle types, including rimed crystals and large aggregates, within the dual-frequency ratio (DFR) plane. The airborne triple-frequency radar data are grouped based on the dominant particle compositions and microphysical processes (level of aggregation and riming). The results from this study are consistent with the main findings of previous modeling studies, with specific regions of the DFR plane associated with unique scattering properties of different ice habits, especially in clouds where the radar signal is dominated by large aggregates. Moreover, the analysis shows close relationships between the triple-frequency signatures and cloud microphysical properties (particle characteristic size, bulk density, and level of riming).