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The present paper is focused on the global spatial (altitude and latitude) structure and seasonal and interannual variability of the migrating diurnal tide derived from the Sounding of the Atmosphere using Broadband Emission Radiometry/Thermosphere‐Ionosphere‐Mesosphere‐Energetics and Dynamics (SABER/TIMED) temperature measurements for 6 full years (January 2002 to December 2007). The tidal results are obtained by a new analysis method where the tides (migrating and nonmigrating) and the planetary waves (zonally traveling and stationary) are simultaneously extracted from the satellite data. It has been found that above 70 km height the SABER migrating diurnal tide reflects mainly the distinctive features of the first symmetric propagating (1,1) mode, while below this height it reflects the features of the first symmetric trapped (1,−2) mode. The trapped component amplifies near 50 km, and its phase is close to ∼1600 LT. The seasonal behavior of the diurnal tide over the equator is dominated by semiannual variation with a primary maximum in February–March (18 K, average amplitude for 6 years) and a secondary maximum in August–September (15 K). The tidal amplitude grows rapidly in the mesosphere/lower thermosphere; however, it undergoes some decay near ∼90 km, defining ubiquitous double‐peaked vertical structure. A very rapid reduction in amplitude is detected at heights near 115 km; however, above this level the diurnal tide amplifies again. The vertical wavelength of the propagating diurnal tide is ∼20 km over the equator; at middle latitudes it is not very different from that over the equator, but its magnitude depends on the season. In the winter it is longer than that in summer. The interannual variability of the diurnal tide indicates a clear correlation with the stratospheric quasi‐biennial oscillation.

Millimeter wave cloud radar (MMCR) is one of the primary instruments employed to observe cloud–precipitation. With appropriate data processing, measurements of the Doppler spectra, spectral moments, and retrievals can be used to study the physical processes of cloud–precipitation. This study mainly analyzed the vertical structures and microphysical characteristics of different kinds of convective cloud–precipitation in South China during the pre-flood season using a vertical pointing Ka-band MMCR. Four kinds of convection, namely, multi-cell, isolated-cell, convective–stratiform mixed, and warm-cell convection, are discussed herein. The results show that the multi-cell and convective–stratiform mixed convections had similar vertical structures, and experienced nearly the same microphysical processes in terms of particle phase change, particle size distribution, hydrometeor growth, and breaking. A forward pattern was proposed to specifically characterize the vertical structure and provide radar spectra models reflecting the different microphysical and dynamic features and variations in different parts of the cloud body. Vertical air motion played key roles in the microphysical processes of the isolated- and warm-cell convections, and deeply affected the ground rainfall properties. Stronger, thicker, and slanted updrafts caused heavier showers with stronger rain rates and groups of larger raindrops. The microphysical parameters for the warm-cell cloud–precipitation were retrieved from the radar data and further compared with the ground-measured results from a disdrometer. The comparisons indicated that the radar retrievals were basically reliable; however, the radar signal weakening caused biases to some extent, especially for the particle number concentration. Note that the differences in sensitivity and detectable height of the two instruments also contributed to the compared deviation.

Vertical mixing is often regarded as the Achilles' heel of ocean models. In particular, few models include a comprehensive and energy‐constrained parameterization of mixing by internal ocean tides. Here, we present an energy‐conserving mixing scheme which accounts for the local breaking of high‐mode internal tides and the distant dissipation of low‐mode internal tides. The scheme relies on four static two‐dimensional maps of internal tide dissipation, constructed using mode‐by‐mode Lagrangian tracking of energy beams from sources to sinks. Each map is associated with a distinct dissipative process and a corresponding vertical structure. Applied to an observational climatology of stratification, the scheme produces a global three‐dimensional map of dissipation which compares well with available microstructure observations and with upper‐ocean finestructure mixing estimates. This relative agreement, both in magnitude and spatial structure across ocean basins, suggests that internal tides underpin most of observed dissipation in the ocean interior at the global scale. The proposed parameterization is therefore expected to improve understanding, mapping, and modeling of ocean mixing. Plain Language Summary When tidal ocean currents flow over bumpy seafloor, they generate internal tidal waves. Internal waves are the subsurface analog of surface waves that break on beaches. Like surface waves, internal tidal waves often become unstable and break into turbulence. This turbulence is a primary cause of mixing between stacked ocean layers—a key process regulating ocean currents and biology and a key ingredient of computer models of the global ocean. In this article, a three‐dimensional global map of mixing induced by internal tidal waves is presented. This map incorporates a large variety of energy pathways from the generation of tidal waves to turbulence, accounting for the conservation of energy. The map is compared to available observations of turbulence across the globe and found to reproduce with good fidelity the main patterns identified in observations. This relatively good agreement suggests that internal tidal waves are the main source of turbulence in the subsurface ocean and implies that the map may serve a range of applications. In particular, the three‐dimensional map provides an efficient and realistic means to represent mixing by internal tidal waves in global ocean models. Key Points A global three‐dimensional map of mixing induced by internal tides is presented The map can serve as a comprehensive and energy‐constrained tidal mixing parameterization in global ocean models The map compares well to available microstructure and upper‐ocean finestructure mixing estimates

The fundamental features of one kind of rarely known stratocumulus, which was termed as “Millipede Cloud,” occurred over the Eastern Pacific Ocean in 2017 were first documented by using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery. These clouds had long and meandering “central axes” extending from several hundreds to thousands kilometers, and a number of “radical cloud arms” extending several tens of kilometers in its two sides. Total 59 “Millipede Clouds,” 4 and 55 of them, were formed over the Northern and the Southern Hemispheres, respectively. Their environmental backgrounds were analyzed by using ERA5 reanalysis data and MODIS sensor Level‐2 data. The cloud top pressures of these “Millipede Clouds” were between 850 and 800 hPa, and their top heights were about 1–2 km. There existed “inversion layer” of air temperature near the cloud tops at 800 hPa, which strongly suggested that these clouds were lower stratocumulus in essence. Plain Language Summary “Millipede Cloud,” one kind of rarely known stratocumulus which looks like “Millipede” shape, is termed for the first time in this paper. It has an obvious “central axis” and a number of well‐organized “radial cloud arms” in two sides of the “central axis” extending in several tens of kilometers length. This paper introduces the fundamental features of “Millipede Clouds” occurred over the Eastern Pacific Ocean in 2017 from the perspective of satellite image. Totally, 59 “Millipede Clouds” were found to occur over the Eastern Pacific Ocean. Their geographic distribution, cloud top features and vertical structure of one typical case on 16 July 2017 were documented. Key Points The fundamental features of “Millipede Clouds” over the Eastern Pacific Ocean in 2017 were documented by using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery The environmental backgrounds of these “Millipede Clouds” were analyzed by using ERA5 reanalysis data and MODIS data The cloud top pressures of these “Millipede Clouds” are between 850 and 800 hPa, and their top heights are about 1–2 km

Aerosol effects on convective precipitation is critical for understanding human impacts on extreme weather and the hydrological cycle. However, even their signs and magnitude remain debatable. In particular, aerosol effects on vertical structure of precipitation have not been systematically examined yet. Combining 6‐year space‐borne and ground‐based observations over the North China Plain, we show a boomerang‐shape aerosol effect on the top height of convective precipitation, from invigoration to suppression. Further analyses reveal that the aerosols play distinct effects on precipitation rate at different layers. Particularly, near surface precipitation rate shows no significant responses to aerosol and precipitation‐top height due to strong evaporation. The competition of energy between released from condensation and freezing and absorbed by evaporation contributes to different responses of precipitation‐top height to aerosol and can explain the boomerang‐shape aerosol effect. Plain Language Summary Aerosol particles in the atmosphere can alter precipitation efficiency and modulate the hydrological cycle, while their impacts on the cloud and precipitation vertical profiles remain poorly understood. Using 6‐year multi‐source observation data along with reanalysis meteorology, we find that aerosols exert distinct effects on precipitation rate at different layers. The observations show that aerosols enhance precipitation‐top height first and then suppress it under various dynamics and thermodynamics conditions, with a turning point at medium aerosol amount. In contrast, the response of near surface precipitation rate to aerosol perturbation is complex due to varying evaporation efficiency. These findings challenge the previous studies that suggested that the characteristics of cloud and precipitation at high altitude are closely correlated with precipitation rate near the surface. Key Points Observations show a boomerang‐shape aerosol effect on the top height of convective precipitation from invigoration to suppression Aerosols impose distinct effects on precipitation rate at different layers, with no significant impact near surface Energy change within conversion processes between hydrometeors and water vapor explains different responses of precipitation to aerosol

A new interpretative approach is proposed to best-estimate of gravity parameters related to simple geometrical shaped structures such as a semi-infinite vertical cylinder, an infinite horizontal cylinder, and a sphere like structures. The proposed technique is based on the multiple-linear regression oriented towards estimating the model parameters, e.g., the depth from the surface to the center of the buried structure (sphere or infinite horizontal cylinder) or the depth from the surface to the top of the buried object (semi-infinite vertical cylinder), the amplitude coefficient, and the horizontal location from residual gravity anomaly profile. The validity of the proposed approach is firstly demonstrated through testing different synthetic data set corrupted and contaminated by a white Gaussian random noise level. The theoretical synthetic obtained results obviously show that the estimated parameters values, derived by the proposed technique are close to the assumed true parameters values. This approach is applied on five real field residual gravity anomalies taken from Cuba, Sweden, Iran, USA, and Germany, where the efficacy of this new approach is consequently proven. A comparable and acceptable agreement is noticed between the results derived by this proposed approach and those obtained from the real field data information.

Evaluating forest ecological integrity remains a major challenge for ecologists. We analyzed understory vegetation using an approach that combined plant functional types and vertical stratification to evaluate the effects of human disturbances on the ecological integrity of sugar maple-dominated stands in southern Québec. Ecological integrity was evaluated by analyzing the divergence of understory species assemblages from those observed in comparable unmanaged forest. Multivariate analyses of biological traits revealed 13 emergent groups that share common traits associated with a similar life history strategy. Responses of these groups, of specific traits, and of understory structure to different human disturbances were tested. Nine of the 13 emergent groups varied in occurrence or diversity among disturbance types. Analyses also revealed a set of traits specifically associated with unmanaged old growth forest, indicating that species possessing these traits may be sensitive to human disturbance. Overall, the understory vegetation assemblage was found to be relatively stable among all human disturbances investigated. However, our results suggest some issues of possible long-term conservation concern given a continuation of human disturbances: (i) an increase of species associated with open environment, including exotic species; (ii) a decrease of spring geophytes; (iii) a decrease of certain shade-tolerant forbs; and (iv) a modification of understory structure by the development of a dense sapling stratum.

The mean vertical structure of mesoscale eddies in the Peru‐Chile Current System is investigated by combining the historical records of Argo float profiles and satellite altimetry data. A composite average of 420 (526) profiles acquired by Argo floats that surfaced into cyclonic (anticyclonic) mesoscale eddies allowed constructing the mean three‐dimensional eddy structure of the eastern South Pacific Ocean. Key differences in their thermohaline vertical structure were revealed. The core of cyclonic eddies (CEs) is centered at ∼150 m depth within the 25.2–26.0 kg m−3 potential density layer corresponding to the thermocline. In contrast, the core of the anticyclonic eddies (AEs) is located below the thermocline at ∼400 m depth impacting the 26.0–26.8 kg m−3 density layer. This difference was attributed to the mechanisms involved in the eddy formation. While intrathermocline CEs would be formed by instabilities of the surface equatorward coastal currents, the subthermocline AEs are likely to be shed by the subsurface poleward Peru‐Chile Undercurrent. In the eddy core, maximum temperature and salinity anomalies are of ±1°C and ±0.1, with positive (negative) values for AEs (CEs). This study also provides new insight into the potential impact of mesoscale eddies for the cross‐shore transport of heat and salt in the eastern South Pacific. Considering only the fraction of the water column associated with the fluid trapped within the eddies, each CE and AE has a typical volume anomaly flux of ∼0.1 Sv and yields to a heat and salt transport anomaly of ±1–3 × 1011 W and ±3–8 × 103 kg s−1, respectively. Key Points A new methodology is proposed to assess the eddy vertical structure from ARGO profiles Cyclonic and anticyclonic eddies show clear distinct vertical structures They impact differently on heat and salt transports of the thermo‐ and subthermocline

The vertical structure of the observed stable boundary layer often deviates substantially from textbook profiles. Even over flat homogeneous surfaces, the turbulence may not be completely related to the surface conditions and instead generated by elevated sources of turbulence such as low-level jets and transient modes. In stable conditions, even modest surface heterogeneity can alter the vertical structure of the stable boundary layer. With clear skies and low wind speeds, cold-air drainage is sometimes generated by very weak slopes and induces a variety of different vertical structures. Our study examines the vertical structure of the boundary layer at three contrasting tower sites. We emphasize low wind speeds with strong stratification. At a given site, the vertical structure may be sensitive to the surface wind direction. Classification of vertical structures is posed primarily in terms of the profile of the heat flux. The nocturnal boundary layer assumes a variety of vertical structures, which can often be roughly viewed as layering of the heat-flux divergence (convergence). The correlation coefficient between the temperature and vertical velocity fluctuations provides valuable additional information for classification of the vertical structure.

The cloud vertical structure (CVS) is important, yet operational CVS products depend on active observation or reanalysis fields, limiting high‐frequency monitoring. In this study, we propose a lightweight and satellite‐only model that reconstructs volumetric cloud masks from geostationary multispectral imagery. This method employs a compact one‐dimensional convolutional neural network that combines three convolutional layers, channel attention and L1 regularization, which is trained on CALIPSO/CloudSat joint profiles and Himawari‐8 multispectral observations. The network produces per‐pixel 38‐layer cloud masks at 500 m vertical resolution and attains strong performance (Intersection over Union = 0.8730; mean absolute error of cloud thicknes = 0.4651 km; cloud top height bias ≈453.25 m). Ablation experiments demonstrate that the chosen architecture and regularization considerably improve layer discrimination. A case study of Typhoon Yutu shows that the reconstructed three‐dimensional structure is consistent with active‐sensor profiles. This observation‐only retrieval reconstructs CVS independent of meteorological inputs, avoiding potential double‐use of geostationary data.