Tactile temporal offset cues reduce visual representational momentum

The perception of dynamic objects is sometimes biased. For example, localizing a moving object after it has disappeared results in a perceptual shift in the direction of motion, a bias known as representational momentum. We investigated whether the temporal characteristics of an irrelevant, spatially uninformative vibrotactile stimulus bias the perceived location of a visual target. In two visuotactile experiments, participants judged the final location of a dynamic, visual target. Simultaneously, a continuous (starting with the onset of the visual target, Experiments 1 and 2) or brief (33-ms stimulation, Experiment 2) vibrotactile stimulus (at the palm of participant’s hands) was presented, and the offset disparity between the visual target and tactile stimulation was systematically varied. The results indicate a cross-modal influence of tactile stimulation on the perceived final location of the visual target. Closer inspection of the nature of this cross-modal influence, observed here for the first time, reveals that the vibrotactile stimulus was likely just taken as a temporal cue regarding the offset of the visual target, but no strong interaction and combined processing of the two stimuli occurred. The present results are related to similar cross-modal temporal illusions and current accounts of multisensory perception, integration, and cross-modal facilitation.

Effects of spatial resolution and temporal offset of air-sea boundary-layer variables on turbulent heat flux estimates

<p>Air-sea turbulent heat fluxes and their spatial gradients are important to the ocean, climate, weather, and their interactions. Satellite-based estimation of air-sea latent and sensible fluxes, providing broad coverage, require measurements of sea surface temperature, ocean-surface wind speed, and air temperature and humidity above sea surface. Because no single satellite has been able to provide simultaneous measurements of these input variables, they typically come from various satellites with different spatial resolutions and sampling times that can be offset by hours. These factors introduce errors in the estimated heat fluxes and their gradients that are not well documented. As a model-based assessment of these errors, we performed a simulation using a Weather Research and Forecasting (WRF) model forced by high-resolution blended satellite SST for the Gulf Stream extension region with a 3-km resolution and with 30-minute output. Latent and sensible heat fluxes were first computed from input variables with the original model resolutions and at coincident times. We then computed the heat fluxes by (1) decimating the input variables to various resolutions from 12.5 to 50 km, and (2) offsetting the “sampling” times of some input variables from others by 3 hours. The resultant estimations of heat fluxes and their gradients from (1) and (2) were compared with the counterparts without reducing resolution and without temporal offset of the input variables. The results show that reducing input-variable resolutions from 12.5 to 50 km weakened the magnitudes of the time-mean and instantaneous heat fluxes and their gradients substantially, for example, by a factor of two for the time-mean gradients. The temporal offset of input variables substantially impacted the instantaneous fluxes and their gradients, although not their time-mean values. The implications of these effects on scientific and operational applications of heat flux products will be discussed. Finally, we highlight a mission concept for providing simultaneous, high-resolution measurements of boundary-layer variables from a single satellite to improve air-sea turbulent heat flux estimation.</p>

Enhanced transport and mixing of Arctic ozone during SSWs

<p><span>The extreme disruptions of the wintertime stratospheric circulation during sudden stratospheric warmings (SSW) have important effects on tracer concentrations through alterations in transport and mixing properties. In this presentation we will examine the dynamics that control changes of Arctic ozone during the life cycle of SSWs, providing a quantitative analysis of both advective transport and mixing of Arctic ozone. We use output from four ensemble members (60 years each) of the Whole Atmospheric Community Climate Model, and also use reanalysis and satellite data for validation purposes. The composite evolution of ozone displays positive mixing ratio anomalies up to 0.5 – 0.6 ppmv above 550 K (∼50 hPa) around the central warming date and negative anomalies below (-0.2 to -0.3 ppmv), consistently in observations, reanalysis and model.</span></p><p><span>Our analysis shows a clear temporal offset between ozone eddy transport and diffusive ozone fluxes. The initial changes in ozone are mainly driven by isentropic eddy fluxes linked to enhanced wave drag responsible for the SSW. The recovery of climatological values in the aftermath of SSWs is slower in the lower than in the upper stratosphere, and is driven by the competing effects of cross-isentropic motions (which work towards the recovery) and isentropic mixing (which delays the recovery). These features are enhanced in strength and duration during sufficiently deep SSWs, particularly those also labeled as Polar-night Jet Oscillation (PJO) events. It is found that SSW-induced ozone concentration anomalies below 600 K (∼40 hPa), as well as total column estimates, persist around one month longer in PJO than in non-PJO warmings.</span></p>

Online Spatial and Temporal Calibration for Monocular Direct Visual-Inertial Odometry

Owing to the nonlinearity in visual-inertial state estimation, sufficiently accurate initial states, especially the spatial and temporal parameters between IMU (Inertial Measurement Unit) and camera, should be provided to avoid divergence. Moreover, these parameters are required to be calibrated online since they are likely to vary once the mechanical configuration slightly changes. Recently, direct approaches have gained popularity for their better performance than feature-based approaches in little-texture or low-illumination environments, taking advantage of tracking pixels directly. Based on these considerations, we perform a direct version of monocular VIO (Visual-inertial Odometry), and propose a novel approach to initialize the spatial-temporal parameters and estimate them with all other variables of interest (IMU pose, point inverse depth, etc.). We highlight that our approach is able to perform robust and accurate initialization and online calibration for the spatial and temporal parameters without utilizing any prior information, and also achieves high-precision estimates even when large temporal offset occurs. The performance of the proposed approach was verified through the public UAV (Unmanned Aerial Vehicle) dataset.

Response of Arctic ozone to sudden stratospheric warmings

Sudden stratospheric warmings (SSWs) are the main source of intra-seasonal and interannual variability in the extratropical stratosphere. The profound alterations to the stratospheric circulation that accompany such events produce rapid changes in the atmospheric composition. The goal of this study is to deepen our understanding of the dynamics that control changes of Arctic ozone during the life cycle of SSWs, providing a quantitative analysis of advective transport and mixing. We use output from four ensemble members (60 years each) of the Whole Atmospheric Community Climate Model version 4 performed for the Chemistry Climate Model Initiative and also use reanalysis and satellite data for validation purposes. The composite evolution of ozone displays positive mixing ratio anomalies of up to 0.5–0.6 ppmv above 550 K (∼ 50 hPa) around the central warming date and negative anomalies below (−0.2 to −0.3 ppmv), consistently in observations, reanalysis, and the model. Our analysis shows a clear temporal offset between ozone eddy transport and diffusive ozone fluxes. The initial changes in ozone are mainly driven by isentropic eddy fluxes linked to enhanced wave drag responsible for the SSW. The recovery of climatological values in the aftermath of SSWs is slower in the lower than in the upper stratosphere and is driven by the competing effects of cross-isentropic motions (which work towards the recovery) and isentropic irreversible mixing (which delays the recovery). These features are enhanced in strength and duration during sufficiently deep SSWs, particularly those followed by polar-night jet oscillation (PJO) events. It is found that SSW-induced ozone concentration anomalies below 600 K (∼ 40 hPa), as well as total column estimates, persist around 1 month longer in PJO than in non-PJO warmings.

Response of Arctic ozone to sudden stratospheric warmings

Sudden stratospheric warmings (SSW) are the main source of intra-seasonal and interannual variability in the extratropical stratosphere. The profound alterations to the stratospheric circulation that accompany such events produce rapid changes in the atmospheric composition. The goal of this study is to deepen our understanding of the dynamics that control changes of Arctic ozone during the life cycle of SSWs, providing a quantitative analysis of advective transport and mixing. We use output from four ensemble members (60 years each) of the Whole Atmospheric Community Climate Model version 4 performed for the Chemistry Climate Model Initiative, and also use reanalysis and satellite data for validation purposes. The composite evolution of ozone displays positive mixing ratio anomalies up to 0.5–0.6 ppmv above 550 K (~ 50 hPa) around the central warming date and negative anomalies below (−0.2 to −0.3 ppmv), consistently in observations, reanalysis and model. Our analysis shows a clear temporal offset between ozone eddy transport and diffusive ozone fluxes. The initial changes in ozone are mainly driven by isentropic eddy fluxes linked to enhanced wave drag responsible for the SSW. The recovery of climatological values in the aftermath of SSWs is slower in the lower than in the upper stratosphere, and is driven by the competing effects of cross-isentropic motions (which work towards the recovery) and isentropic irreversible mixing (which delays the recovery). These features are enhanced in strength and duration during sufficiently deep SSWs, particularly those followed by Polar-night Jet Oscillation (PJO) events. It is found that SSW-induced ozone concentration anomalies below 600 K (~ 40 hPa), as well as total column estimates, persist around one month longer in PJO than in non-PJO warmings.

Sensitivity of the Brewer–Dobson Circulation and Polar Vortex Variability to Parameterized Nonorographic Gravity Wave Drag in a High-Resolution Atmospheric Model

The role of parameterized nonorographic gravity wave drag (NOGWD) and its seasonal interaction with the resolved wave drag in the stratosphere has been extensively studied in low-resolution (coarser than 1.9° × 2.5°) climate models but is comparatively unexplored in higher-resolution models. Using the European Centre for Medium-Range Weather Forecasts Integrated Forecast System at 0.7° × 0.7° resolution, the wave drivers of the Brewer–Dobson circulation are diagnosed and the circulation sensitivity to the NOGW launch flux is explored. NOGWs are found to account for nearly 20% of the lower-stratospheric Southern Hemisphere (SH) polar cap downwelling and for less than 10% of the lower-stratospheric tropical upwelling and Northern Hemisphere (NH) polar cap downwelling. Despite these relatively small numbers, there are complex interactions between NOGWD and resolved wave drag, in both polar regions. Seasonal cycle analysis reveals a temporal offset in the resolved and parameterized wave interaction: the NOGWD response to altered source fluxes is largest in midwinter, while the resolved wave response is largest in the late winter and spring. This temporal offset is especially prominent in the SH. The impact of NOGWD on sudden stratospheric warming (SSW) life cycles and the final warming date in the SH is also investigated. An increase in NOGWD leads to an increase in SSW frequency, reduction in amplitude and persistence, and an earlier recovery of the stratopause following an SSW event. The SH final warming date is also brought forward when NOGWD is increased. Thus, NOGWD is still found to be a very important parameterization for stratospheric dynamics even in a high-resolution atmospheric model.

Brainstem network dynamics underlying the encoding of bladder information

Urodynamic status must interact with arousal and attentional processes so that voiding occurs under appropriate conditions. To elucidate the central encoding of this visceral demand, multisite recordings were made within a putative pontine-cortical micturition circuit from the pontine micturition center (PMC), locus coeruleus (LC) and medial prefrontal cortex (mPFC) during cystometry in unanesthetized rats. PMC neurons had homogeneous firing patterns, characterized by tonic activity and phasic bursts that were temporally associated with distinct phases of the micturition cycle. LC and cortical activation became synchronized 20-30 s prior to micturition. During this pre-micturition interval, a theta oscillation developed in the LC, the mPFC desynchronized and LC-mPFC coherence increased in the theta frequency range. The temporal offset between the shift in LC-mPFC network activity and micturition may allow time to disengage from ongoing behaviors unrelated to micturition and initiate specific voiding behaviors so that micturition occurs in environmentally and socially appropriate conditions.

The absence or temporal offset of visual feedback does not influence adaptation to novel movement dynamics

Delays in transmitting and processing sensory information require correctly associating delayed feedback to issued motor commands for accurate error compensation. The flexibility of this alignment between motor signals and feedback has been demonstrated for movement recalibration to visual manipulations, but the alignment dependence for adapting movement dynamics is largely unknown. Here we examined the effect of visual feedback manipulations on force-field adaptation. Three subject groups used a manipulandum while experiencing a lag in the corresponding cursor motion (0, 75, or 150 ms). When the offset was applied at the start of the session (continuous condition), adaptation was not significantly different between groups. However, these similarities may be due to acclimation to the offset before motor adaptation. We tested additional subjects who experienced the same delays concurrent with the introduction of the perturbation (abrupt condition). In this case adaptation was statistically indistinguishable from the continuous condition, indicating that acclimation to feedback delay was not a factor. In addition, end-point errors were not significantly different across the delay or onset conditions, but end-point correction (e.g., deceleration duration) was influenced by the temporal offset. As an additional control, we tested a group of subjects who performed without visual feedback and found comparable movement adaptation results. These results suggest that visual feedback manipulation (absence or temporal misalignment) does not affect adaptation to novel dynamics, independent of both acclimation and perceptual awareness. These findings could have implications for modeling how the motor system adjusts to errors despite concurrent delays in sensory feedback information.NEW & NOTEWORTHY A temporal offset between movement and distorted visual feedback (e.g., visuomotor rotation) influences the subsequent motor recalibration, but the effects of this offset for altered movement dynamics are largely unknown. Here we examined the influence of 1) delayed and 2) removed visual feedback on the adaptation to novel movement dynamics. These results contribute to understanding of the control strategies that compensate for movement errors when there is a temporal separation between motion state and sensory information.