A description of the daily cycle of oceanic shallow cumulus for undisturbed boreal winter conditions in the North Atlantic trades is presented. Modern investigation tools are used, including storm‐resolving and large‐eddy simulations, runover large domains in realistic configurations, and observations from in situ measurements and satellite‐based retrievals. Models and observations clearly show pronounced diurnal variations in cloudiness, both near cloud base and below the trade inversion. The daily cycle reflects the evolution of two cloud populations: (i) a population of nonprecipitating small cumuli with weak vertical extent, which grows during the day and maximizes around sunset, and (ii) a population o deeper precipitating clouds with a stratiform cloud layer below the trade inversion, which grows during the night and maximizes just before sunrise. Previous studies have reported that cloudiness near cloud base undergoes weak variations on time scales longer than a day. However, here we find that it can vary strongly at the diurnal time scale. This daily cycle could serve as a critical test of the models' representation of the physical processes controlling cloudiness near cloud base, which is thought to be key for the determination of the Earth's climate response to warming.

[1] A sawtooth event is identified as a series of energetic particle flux variations, i.e., rapid increases following slow decreases, from geosynchronous satellites observations. The saw blade shape is prominent in the proton flux with energy range between 50 and 400 keV. Though sawtooth events are described as large-amplitude oscillations with periods between 2 and 4 h on the basis of case studies, their period has not been accurately determined by previous studies. In this study, we have identified 111 sawtooth event intervals, which include 438 individual teeth, from January 1998 to December 2007. We find the average period is 179.6 min. However, the period shows large variations from event to event, even from tooth to tooth in the same sawtooth interval. The variability is independent with the length of the period and the number of oscillations, so we conclude that sawtooth events are quasi-periodic events instead of periodic events.

To achieve the wearable comfort of electronic skin (e-skin), a capacitive sensor printed on a flexible textile substrate with a carbon black (CB)/silicone rubber (SR) composite dielectric was demonstrated in this paper. Organo-silicone conductive silver adhesive serves as a flexible electrodes/shielding layer. The structure design, sensing mechanism and the influence of the conductive filler content and temperature variations on the sensor performance were investigated. The proposed device can effectively enhance the flexibility and comfort of wearing the device asthe sensing element has achieved a sensitivity of 0.02536%/KPa, a hysteresis error of 5.6%, and a dynamic response time of ~89 ms at the range of 0-700 KPa. The drift induced by temperature variations has been calibrated by presenting the temperature compensation model. The research on the time-space distribution of plantar pressure information and the experiment of the manipulator soft-grasping were implemented with the introduced device, and the experimental results indicate that the capacitive flexible textile tactile sensor has good stability and tactile perception capacity. This study provides a good candidate for wearable artificial skin.

[1] Different magnetospheric dynamic processes, such as sawtooth events, isolated substorms, and steady magnetospheric convection (SMC), can occur, depending on the solar wind condition. The purpose of this study is to calculate the magnetic flux in the magnetotail and in the polar cap during these magnetospheric modes and to establish a quantitative relation between the magnetic flux and the solar wind parameters. We use the Imager for Magnetopause-to-Aurora Global Exploration Far Ultraviolet Imager and Polar Ultraviolet Imager measurements to derive the magnetic flux in the polar cap and the Geotail measurements to derive the magnetic flux in the magnetotail. The average value of the magnetic flux at the sawtooth onset is $1 GWb in the polar cap and magnetotail, and the relative decrease of the magnetic flux from the maximum value at the sawtooth onset to the minimum value after the onset is 24-26.5%. The average magnetic flux in the polar cap at the onset of isolated substorms is 0.68 GWb and decreases by 26.5% after the expansion phase. The magnetic flux in the polar cap during SMC events varies between 0.3 and 0.8 GWb. The magnetic flux at the isolated substorm onset is at the upper limit of the magnetic flux of SMC events for the same merging electric field, and the magnetic flux at the sawtooth onset is always higher than that during isolated substorms and during SMC events. The magnetic flux in the magnetotail and polar cap during sawtooth events and isolated substorms increases gradually before the onset and then decreases rapidly after the onset, which is consistent with the traditional energy loading-unloading scenario. However, the maximum magnetic flux at the sawtooth or isolated substorm onset is not a constant but increases with the merging electric field and with the corrected Dst index. The results also provide reasonable explanation of the relatively constant period of sawtooth events.Citation: Huang, C.-S., A. D. DeJong, and X. Cai (2009), Magnetic flux in the magnetotail and polar cap during sawteeth, isolated substorms, and steady magnetospheric convection events,

We compare the cloud detection and cloud phase determination of three independent climatologies based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) to airborne in situ measurements. Our analysis of the cloud detection shows that the differences between the satellite and in situ measurements mainly arise from three factors. First, averaging CALIPSO Level l data along track before cloud detection increases the estimate of high-and low-level cloud fractions. Second, the vertical averaging of Level 1 data before cloud detection tends to artificially increase the cloud vertical extent. Third, the differences in classification of fully attenuated pixels among the CALIPSO climatologies lead to differences in the low-level Arctic cloud fractions. In another section, we compare the cloudy pixels detected by colocated in situ and satellite observations to study the cloud phase determination. At midlatitudes, retrievals of homogeneous high ice clouds by CALIPSO data sets are very robust (more than 94.6% of agreement with in situ). In the Arctic, where the cloud phase vertical variability is larger within a 480 m pixel, all climatologies show disagreements with the in situ measurements and CALIPSO-General Circulation Models-Oriented Cloud Product (GOCCP) report significant undefined-phase clouds, which likely correspond to mixed-phase clouds. In all CALIPSO products, the phase determination is dominated by the cloud top phase. Finally, we use global statistics to demonstrate that main differences between the CALIPSO cloud phase products stem from the cloud detection (horizontal averaging, fully attenuated pixels) rather than the cloud phase determination procedures. 100 km) and have been used recently to emphasize models' flaws [Cesana et al., 2015; Komurcu et al., 2014]. CESANA ET AL. CALIPSO CLOUD PHASE VALIDATION 5788