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Aiming at the actual demand of wide-frequency vibration isolation and low-frequency shock resistance of the vibration isolation system for complex external excitation of the aircraft turboprop engine. The dynamic performance of a certain type of turbo-propeller engine vibration isolation system at a 1.5–2000 Hz vibration frequency is investigated by combining simulations and experimental research. Firstly, an equivalent test device for the vibration isolation system of an aircraft turboprop engine is designed, and the reliability of the device structure is verified by finite-element analysis. Then, based on the trial model, sweep frequency vibration tests in three vibration directions are carried out, and the vibration isolation performance of the vibration isolation system under random excitation is analyzed. Finally, the transfer functions of the vibration isolation system in three vibration directions are calculated, and the vibration amplification of the vibration isolation system subjected to low-frequency resonance is analyzed. It provides a test basis and idea for the optimization design of the aero-engine vibration isolation system.

​​​​​​​Land–atmosphere coupling (LAC) has long been studied, focusing on land surface and atmospheric boundary layer processes. However, the influence of humidity in the lower troposphere (LT), especially that above the planetary boundary layer (PBL), on LAC remains largely unexplored. In this study, we use radiosonde observations from the US Southern Great Plains (SGP) site and an entrained parcel buoyancy model to investigate the impact of LT humidity on LAC there during the warm season (May–September). We quantify the effect of LT humidity on convective buoyancy by measuring the difference between the 2–4 km vertically integrated buoyancy with the influence of background LT humidity and that without it. Our results show that, under dry soil conditions, anomalously high LT humidity is necessary to produce the buoyancy profiles required for afternoon precipitation events (APEs). These APEs under dry soil moisture cannot be explained by commonly used local LAC indices such as the convective triggering potential and low-level humidity index (CTP / HILow), which do not account for the influence of the LT humidity. On the other hand, consideration of LT humidity is unnecessary to explain APEs under wet soil moisture conditions, suggesting that the boundary layer moisture alone could be sufficient to generate the required buoyancy profiles. These findings highlight the need to consider the impact of LT humidity, which is often decoupled from the humidity near the surface and is largely controlled by moisture transport, in understanding land–atmospheric feedbacks under dry soil conditions, especially during droughts or dry spells over the SGP.

The Great Plains and southwest regions of the US are highly vulnerable to precipitation-related climate disasters such as droughts and floods. In this study, we propose a self-organizing map–analogue (SOMA) approach to empirically quantify the contribution of atmospheric moist circulation (mid-tropospheric geopotential and column moisture transport) to the regional precipitation anomalies, variability, and multi-decadal changes. Our results indicate that moist circulation contributes significantly to short-term precipitation variability, accounting for 54 %–61 % of the total variance in these regions, though these contributions vary significantly across seasons. As indicated in previous research, Pacific Decadal Oscillation (PDO) is one of the major climate modes influencing the long-term multi-decadal variation in precipitation. By contrasting three multi-decadal periods (1950–1976, 1977–1998, 1999–2021) with shifting PDO phases and linking the phase shift to self-organizing map (SOM) nodes, we found that circulation changes contribute considerably to the multi-decadal changes in precipitation anomaly in terms of the mean and days of dry and wet extremes, especially for the southern Great Plains (GP) and southwest. However, these circulation-induced changes are not totally related to the PDO phase shift (mostly less than half) since internal variability or anthropogenically induced changes in circulation can also be potential contributors. Our approach improves upon flow analogue and SOM-based methods and provides insights into the contribution of atmospheric circulation to regional precipitation anomalies and variability.

Biocrust is a key component of ecosystems and plays a vital role in altering hydrological processes in terrestrial ecosystems. The impacts of biocrust on hydrological processes in arid and semi-arid ecosystems have been widely documented. However, the effects and mechanisms of biocrust on soil hydrological processes in alpine ecosystems are still poorly understood. In this study, we selected two meadow types from the northern Qinghai–Tibet Plateau: normal Kobresia meadow (NM) and biocrust meadow (BM). Both the soil hydrological and physicochemical properties were examined. We found that, in the 0–30 cm soil layer, soil water retention and soil water content in NM were higher than those in BM, whereas the 30–40 cm layer's soil water retention and soil water content in NM were lower than those in BM. The topsoil infiltration rate in BM was lower than that in NM. Furthermore, the physicochemical properties were different between NM and BM. The 0–10 cm soil layer's clay content in BM was 9 % higher than that in NM, whereas the 0–30 cm layer's soil capillary porosity in NM was higher than that in BM. In addition, the 0–20 cm layer's soil total nitrogen (TN) and soil organic matter (SOM) in NM were higher than those in BM, implying that the presence of biocrust may not favor the formation of soil nutrients owing to its lower soil microbial biomass carbon and microbial biomass nitrogen. Overall, soil water retention was determined by SOM by altering the soil capillary porosity and bulk density. Our findings suggest that the establishment of cyanobacteria crust biocrust may not improve soil water retention and infiltration, and the soil in cyanobacteria crust meadows could be more vulnerable to runoff generation and consequent soil erosion. These results provide a systematic and comprehensive understanding of the effects of biocrust on the soil hydrology of alpine ecosystems.

Implantation is an essential issue in orthopedic surgery. Bulk metallic glasses (BMGs), as a kind of novel materials, attract lots of attentions in biological field owing to their comprehensive excellent properties. Here, we show that a Zr61Ti2Cu25Al12 (at. %) BMG (Zr-based BMG) displays the best cytocompatibility, pronounced positive effects on cellular migration, and tube formation from in-vitro tests as compared to those of commercial-pure titanium and poly-ether-ether-ketone. The in-vivo micro-CT and histological evaluation demonstrate the Zr-based BMG can significantly promote a bone formation. Immunofluorescence tests and digital reconstructed radiographs manifest a stimulated effect on early blood vessel formation from the Zr-based BMG. Accordingly, the intimate connection and coupling effect between angiogenesis and osteogenesis must be effective during bone regeneration after implanting Zr-based BMG. Dynamic gait analysis in rats after implanting Zr-based BMG demonstrates a tendency to decrease the pain level during recovery, simultaneously, without abnormal ionic accumulation and inflammatory reactions. Considering suitable mechanical properties, we provide a realistic candidate of the Zr61Ti2Cu25Al12 BMG for biomedical applications.

Peatlands are a major carbon (C) sink globally. Organic matter quality influence greenhouse gases production. However, little is known about how organic matter from different vegetation types, influences C composition and resultant greenhouse gases production in subtropical peatland. Anoxic incubation experiments were conducted using two types of peats with different botanical origin to assess C composition, CO2 and CH4 production. First peat had cypress dominance and the second knotted spikerush and water lily (spike + lily). Solid-state CPMAS 13C NMR determined C chemical stability, MESTA determined C thermal stability, stable isotopes for C source and gas chromatograph for carbon dioxide (CO2) and methane (CH4). The results indicated dominance of autochthonous C as indicated by δ13C signatures. Low thermal stable C (LTSC) dominated in litter, FL (fermentation layer) and spike + lily sediment, high thermal stable C was dominant in cypress peat. O-alkyl C strongly correlated with LTSC whereas aromatic C correlated negatively with R400 (LTSC:total C ratio). Generally, O-alkyl decreased and alkyl increased along litter-FL-peat continuum. Spike + lily peat exhibited initial stage of decomposition. Indicated by increased alkyl C, aromatic C and aromatic:O-alkyl ratio with increasing peat depth. Also, exhibited 3 times more CH4 and CO2 production compared to cypress peat that dominantly exhibited second stage of decomposition. O-alkyl C exhibited positive relationship with CH4 (P = 0.012, r2 = 0.57) and CO2 (P = 0.047, r2 = 0.41) production whereas R400 related positively with CH4 (P = 0.05, r2 = 0.40). Organic matter thermal and chemical composition varied between the peat types and thermally and chemically labile C influenced CO2 and CH4 production.

The boreal summer dry season length is reported to have been increasing in the last 3 decades over the Congo rainforest, which is the second-largest rainforest in the world. In some years, the wet season in boreal autumn starts early, while in others it arrives late. The mechanism behind such a change in the wet season onset date has not been investigated yet. Using multi-satellite data sets, we discover that the variation in aerosols in the dry season plays a major role in determining the subsequent wet season onset. Dry season aerosol optical depth (AOD) influences the strength of the southern African easterly jet (AEJ-S) and, thus, the onset of the wet season. Higher AOD associated with a higher dust mass flux reduces the net downward shortwave radiation and decreases the surface temperature over the Congo rainforest region, leading to a stronger meridional temperature gradient between the rainforest and the Kalahari Desert as early as in June. The latter, in turn, strengthens the AEJ-S, sets in an early and a stronger easterly flow, and leads to a stronger equatorward convergence and an early onset of the wet season in late August to early September. The mean AOD in the dry season over the region is strongly correlated (r=0.7) with the timing of the subsequent wet season onset. Conversely, in low AOD years, the onset of the wet season over the Congo basin is delayed to mid-October.

This study addresses the role of the atmospheric moisture budget in determining the onset and development of summer droughts over the North American Great Plains (GP) using two state-of-the-art reanalysis datasets. We identified zonal moisture advection as the main cause of severe tropospheric drying during the extreme droughts in the southern GP in 2011 and northern GP in 2012. For both events, the eastward advection of anomalously dry and warm air in the free troposphere in spring set the stage for summer drought. This led to a sharp drop in relative humidity above the boundary layer, enhancing dry entrainment and suppressing deep convection. Further breakdown of the zonal advection into dynamic (caused by circulation anomalies) and thermodynamic (caused by moisture anomalies) contributions reveals dominance of thermodynamic advection in the tropospheric drying observed during the onset of both 2011 and 2012 droughts. The dependence of thermodynamic advection on the moisture gradient links springtime precipitation in the Rockies and southwestern US, the source region of the anomalous dry advection, to the GP summer precipitation (with correlations > 0.4 using gauge-based data). Identifying this previously overlooked precursor of the GP summer droughts improves our predictive understanding of drought onset mechanisms over the region.

Locally available organic inputs to soil, solely or in combination with inorganic fertilizers, are used to reverse declining soil fertility and improve soil organic matter content (SOM) in smallholder farms of most Sub-Saharan Africa (SSA) countries. Soil organic matter characterization can indicate soil organic input, carbon (C) sequestration potential, or even an authentication tool for soil C dynamics in C stocks accounting. This study determined the effects of the long-term application of selected integrated soil fertility management (ISFM) technologies on SOM functional group composition and maize yields. The study was carried out on an ongoing long-term soil fertility field experiment established in 2004 in Mbeere South sub-county, the drier part of upper Eastern Kenya. The experimental design was a randomized complete block design. The ISFM treatments were 60 kg ha−1 nitrogen (N) from goat manure (GM60); 30 kg ha−1 inorganic N fertilizer (IF30); 60 kg ha−1 inorganic N fertilizer (IF60); GM30+IF30; 90 kg ha−1 inorganic N fertilizer (IF90); 60 kg ha−1 N from lantana (Lantana camara) (LC60); LC30+IF30; 60 kg ha−1 N from mucuna beans (Mucuna pruriens) (MP60); MP30+IF30; 60 kg ha−1 N from Mexican sunflower (Tithonia diversifolia) (TD60); TD30+IF30, and a control with no inputs. The C compositions of ground soil samples and organic amendments were analyzed using 13C solid-state NMR. The GM60, GM30+IF30, LC60, and TD60 treatments had much higher Alkyl and O-Alkyl C SOM functional groups than the control and other treatments. The average soil C for the control was 7.47 mg kg−1 and ranged from 5.03 to 7.37, 9.57 to 18.77, and 7.03–14.50 mg kg−1 for inorganic fertilizers, organic fertilizers, and organic + inorganic fertilizers, respectively. The mean grain yield for the control was 0.56 Mg ha−1 and ranged from 1.51 to 1.99, 1.94 to 4.16, and 2.98–4.60 Mg ha−1 for inorganic fertilizers, organic fertilizers, and organic + inorganic fertilizers, respectively. The results showed that a long-term application of sole organic fertilizers or combined with inorganic fertilizers increases maize yield and soil C sequestration potential. The increase was attributed to high Alkyl and O-Alkyl C SOM functional groups. Hence, knowing the C fraction content of organic inputs is vital in determining the best-fit management technologies for ameliorating soil fertility and sustaining and/or improving crop yields.

The continental tropics play a leading role in the terrestrial energy, water, and carbon cycles. Land–atmosphere interactions are integral in the regulation of these fluxes across multiple spatial and temporal scales over tropical continents. We review here some of the important characteristics of tropical continental climates and how land–atmosphere interactions regulate them. Along with a wide range of climates, the tropics manifest a diverse array of land–atmosphere interactions. Broadly speaking, in tropical rainforest climates, light and energy are typically more limiting than precipitation and water supply for photosynthesis and evapotranspiration (ET), whereas in savanna and semi-arid climates, water is the critical regulator of surface fluxes and land–atmosphere interactions. We discuss the impact of the land surface, how it affects shallow and deep clouds, and how these clouds in turn can feed back to the surface by modulating surface radiation and precipitation. Some results from recent research suggest that shallow clouds may be especially critical to land–atmosphere interactions. On the other hand, the impact of land-surface conditions on deep convection appears to occur over larger, nonlocal scales and may be a more relevant land–atmosphere feedback mechanism in transitional dry-to-wet regions and climate regimes.

Sediment from three reservoirs located in the Little Washita River Experimental Watershed (LWREW) in Oklahoma, USA with contrasting dominant land uses were analyzed for total and extractable concentrations of arsenic (As) and chromium (Cr), and the potential ecologic risk to benthic organisms. Extractable As ranged from 0.24 to 1.21 mg kg−1, in the order grazing>cropland>forest and 0.13–0.58 mg kg−1 for extractable Cr, in the order of forest>grazing>cropland. However, only approximately grazing>forest. The sediment exhibited an alkaline pH (8.0–8.7). As sorption exhibited a positive relationship with Al (r = 0.9995; P = 0.0001), Fe (r = 0.9829; P = 0.0001), and C (r = 0.4090; P = 0.0017) and Cr correlated positively with Al (r = 0.9676 P = 0.0001), Fe (r = 0.9818; P = 0.0001), and C (r = 0.3368; P = 0.0111). In addition, both As and Cr exhibited positive relationships with carbon (C) functional groups in the order of O-alkyl C> methoxyl C> alkyl C> aromatic C> carboxyl C> phenolic C. The sediment concentration analysis results illustrated that As in all reservoirs exceeded their respective Threshold Effect Level (TEL) and/or Probable Effect Level (PEL) indicating that existing concentrations of metals in these sediments were sufficiently high to cause adverse effects. However, Cr concentrations in all reservoirs evaluated was lower compared to the TEL and PEL.

The preconditioning of the atmosphere for a shallow-to-deep convective transition during the dry-to-wet season transition period (August–November) is investigated using Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) GoAmazon2014/5 campaign data from March 2014 to November 2015 in Manacapuru, Brazil. In comparison to conditions observed prior to shallow convection, anomalously high humidity in the free troposphere and boundary layer is observed prior to a shallow-to-deep convection transition. An entraining plume model, which captures this leading dependence on lower tropospheric moisture, is employed to study indirect thermodynamic effects associated with vertical wind shear (VWS) and cloud condensation nuclei (CCN) concentration on preconvective conditions. The shallow-to-deep convective transition primarily depends on humidity, especially that from the free troposphere, which tends to increase plume buoyancy. Conditions preceding deep convection are associated with high relative humidity, and low-to-moderate CCN concentration (less than the 67th percentile, 1274 cm−3). VWS, however, shows little relation to moisture and plume buoyancy. Buoyancy estimates suggest that the latent heat release due to freezing is important to deep convective growth under all conditions analyzed, consistent with potential pathways for aerosol effects, even in the presence of a strong entrainment. Shallow-only convective growth, however, shows an association with a strong (weak) low (deep) level VWS and with higher CCN concentration.

The interactions between aerosols and ice clouds represent one of the largest uncertainties in global radiative forcing from pre-industrial time to the present. In particular, the impact of aerosols on ice crystal effective radius (Rei), which is a key parameter determining ice clouds' net radiative effect, is highly uncertain due to limited and conflicting observational evidence. Here we investigate the effects of aerosols on Rei under different meteorological conditions using 9-year satellite observations. We find that the responses of Rei to aerosol loadings are modulated by water vapor amount in conjunction with several other meteorological parameters. While there is a significant negative correlation between Rei and aerosol loading in moist conditions, consistent with the "Twomey effect" for liquid clouds, a strong positive correlation between the two occurs in dry conditions. Simulations based on a cloud parcel model suggest that water vapor modulates the relative importance of different ice nucleation modes, leading to the opposite aerosol impacts between moist and dry conditions. When ice clouds are decomposed into those generated from deep convection and formed in situ, the water vapor modulation remains in effect for both ice cloud types, although the sensitivities of Rei to aerosols differ noticeably between them due to distinct formation mechanisms. The water vapor modulation can largely explain the difference in the responses of Rei to aerosol loadings in various seasons. A proper representation of the water vapor modulation is essential for an accurate estimate of aerosol–cloud radiative forcing produced by ice clouds.

Recent research in large-scale hydroclimatic variability is surveyed, focusing on five topics: (i) variability in general, (ii) droughts, (iii) floods, (iv) land–atmosphere coupling, and (v) hydroclimatic prediction. Each surveyed topic is supplemented by illustrative examples of recent research, as presented at a 2016 symposium honoring the career of Professor Eric Wood. Taken together, the recent literature and the illustrative examples clearly show that current research into hydroclimatic variability is strong, vibrant, and multifaceted.

The onset and demise of the rainy season in Amazonia are assessed in this study using meteorological data from the GoAmazon experiment, with a focus on the 2014–2015 rainy season. In addition, global reanalyses are also used to identify changes in circulation leading to the establishment of the rainy season in the region. Our results show that the onset occurred in January 2015, 2–3 pentads later than normal, and the rainy season during the austral summer of 2015 contained several periods with consecutive dry days in both Manacapuru and Manaus, which are not common for the wet season, and resulted in below-normal precipitation. The onset of the rainy season has been strongly associated with changes in large-scale weather conditions in the region due to the effect of the Madden–Julian Oscillation (MJO). Regional thermodynamic indices and the height of the boundary layer did not present a significant difference between the onset and demise of the wet season of 2015. This suggests that local changes, such as those in the regional thermodynamic characteristics, may not have influenced its onset. Thus, variability of the large-scale circulation was responsible for regional convection and rainfall changes in Amazonia during the austral summer of 2014–2015.

The Asian monsoon region is the most prominent moisture center of water vapor in the lower stratosphere (LS) during boreal summer. Previous studies have suggested that the transport of water vapor to the Asian monsoon LS is controlled by dehydration temperatures and convection mainly over the Bay of Bengal and Southeast Asia. However, there is a clear geographic variation of convection associated with the seasonal and intra-seasonal variations of the Asian monsoon circulation, and the relative influence of such a geographic variation of convection vs. the variation of local dehydration temperatures on water vapor transport is still not clear. Using satellite observations from the Aura Microwave Limb Sounder (MLS) and a domain-filling forward trajectory model, we show that almost half of the seasonal water vapor increase in the Asian monsoon LS are attributable to geographic variations of convection and resultant variations of the dehydration center, of which the influence is comparable to the influence of the local dehydration temperature increase. In particular, dehydration temperatures are coldest over the southeast and warmest over the northwest Asian monsoon region. Although the convective center is located over Southeast Asia, an anomalous increase of convection over the northwest Asia monsoon region increases local diabatic heating in the tropopause layer and air masses entering the LS are dehydrated at relatively warmer temperatures. Due to warmer dehydration temperatures, anomalously moist air enters the LS and moves eastward along the northern flank of the monsoon anticyclonic flow, leading to wet anomalies in the LS over the Asian monsoon region. Likewise, when convection increases over the Southeast Asia monsoon region, dry anomalies appear in the LS. On a seasonal scale, this feature is associated with the monsoon circulation, convection and diabatic heating marching towards the northwest Asia monsoon region from June to August. The march of convection leads to an increasing fraction of the air mass to be dehydrated at warmer temperatures over the northwest Asia monsoon region. Work presented here confirms the dominant role of temperatures on water vapor variations and emphasizes that further studies should take geographic variations of the dehydration center into consideration when studying water vapor variations in the LS as it is linked to changes of convection and large-scale circulation patterns.

This study investigates the impacts of fire emission, convection, various climate conditions and transport pathways on the interannual variation of carbon monoxide (CO) in the tropical upper troposphere (UT), by evaluating the field correlation between these fields using multi-satellite observations and principle component analysis, and the transport pathway auto-identification method developed in our previous study. The rotated empirical orthogonal function (REOF) and singular value decomposition (SVD) methods are used to identify the dominant modes of CO interannual variation in the tropical UT and to study the coupled relationship between UT CO and its governing factors. Both REOF and SVD results confirm that Indonesia is the most significant land region that affects the interannual variation of CO in the tropical UT, and El Niño–Southern Oscillation (ENSO) is the dominant climate condition that affects the relationships between surface CO emission, convection and UT CO. In addition, our results also show that the impact of El Niño on the anomalous CO pattern in the tropical UT varies strongly, primarily due to different anomalous emission and convection patterns associated with different El Niño events. In contrast, the anomalous CO pattern in the tropical UT during La Niña period appears to be less variable among different events. Transport pathway analysis suggests that the average CO transported by the "local convection" pathway (ΔCOlocal) accounts for the differences of UT CO between different ENSO phases over the tropical continents during biomass burning season. ΔCOlocal is generally higher over Indonesia–Australia and lower over South America during El Niño years than during La Niña years. The other pathway ("advection within the lower troposphere followed by convective vertical transport") occurs more frequently over the west-central Pacific during El Niño years than during La Niña years, which may account for the UT CO differences over this region between different ENSO phases.

Past studies have identified a variety of pathways by which carbon monoxide (CO) may be transported from the surface to the tropical upper troposphere (UT); however, the relative roles that these transport pathways play in determining the distribution and seasonality of CO in the tropical UT remain unclear. We have developed a method to automate the identification of two pathways ("local convection" and "advection within the lower troposphere (LT) followed by convective vertical transport") involved in CO transport from the surface to the UT. This method is based on the joint application of instantaneous along-track, co-located, A-Train satellite measurements. Using this method, we find that the locations and seasonality of the UT CO maxima in the tropics were strongly correlated with the frequency of local convective transport during 2007. We also find that the "local convection" pathway (convective transport that occurred within a fire region) typically transported significantly more CO to the UT than the "LT advection → convection" pathway (advection of CO within the LT from a fire region to a convective region prior to convective transport). To leading order, the seasonality of CO concentrations in the tropical UT reflected the seasonality of the "local convection" transport pathway during 2007. The UT CO maxima occurred over Central Africa during boreal spring and over South America during austral spring. Occurrence of the "local convection" transport pathway in these two regions also peaked during these seasons. During boreal winter and summer, surface CO emission and convection were located in opposite hemispheres, which limited the effectiveness of transport to the UT. During these seasons, CO transport from the surface to the UT typically occurred via the "LT advection → convection" pathway.

In the present work, we investigate the effect of dipole interactions on hyperthermia heating the cluster composed of multi superparamagnetic nanoparticles via time-quantified Monte Carlo simulation. The dynamic hysteresis loop area of non-interacting particles calculated by a modified Rosensweig’s model is shown to be proportional to the field frequency. The inverse of the total number of Monte Carlo steps per field cycle is considered as a computational frequency in our modelling. By comparing the two proportionality constants gained from the simulation and from the Rosensweig’s model, respectively, the time scale of one Monte Carlo step is estimated. The shape of the cluster is characterised by treating it as an equivalent ellipsoid. When the morphology of cluster is highly anisotropic such in a chain and cylinder, dipole interactions align the moments of the particles to the morphology anisotropy axis of the cluster. The strength of such alignment depends on the magnitude of morphology anisotropy of the cluster. The alignment helps improve heating capability of the chain and cylinder clusters at the most angles between the field direction and morphology anisotropy axis. However, when the field direction is away from the axis too much, the high energy barrier will hamper the cluster to maintain the magnetization, leading to a reduced heating efficiency. Once the cluster loses its morphology anisotropy (i.e. cube), the influence of dipole interactions on hysteresis losses is reduced to the minimum; the probability to obtain an improved heating becomes very low no matter with the type of particle arrangement.

The factors that control the influence of deep convective detrainment on water vapor in the tropical upper troposphere are examined using observations from multiple satellites in conjunction with a trajectory model. Deep convection is confirmed to act primarily as a moisture source to the upper troposphere, modulated by the ambient relative humidity (RH). Convective detrainment provides strong moistening at low RH and offsets drying due to subsidence across a wide range of RH. Strong day-to-day moistening and drying takes place most frequently in relatively dry transition zones, where between 0.01% and 0.1% of Tropical Rainfall Measuring Mission Precipitation Radar observations indicate active convection. Many of these strong moistening events in the tropics can be directly attributed to detrainment from recent tropical convection, while others in the subtropics appear to be related to stratosphere-troposphere exchange. The temporal and spatial limits of the convective source are estimated to be about 36–48 h and 600–1500 km, respectively, consistent with the lifetimes of detrainment cirrus clouds. Larger amounts of detrained ice are associated with enhanced upper tropospheric moistening in both absolute and relative terms. In particular, an increase in ice water content of approximately 400% corresponds to a 10–90% increase in the likelihood of moistening and a 30–50% increase in the magnitude of moistening.

This study investigates the national expansion of urban and artificial coverages in Chile between 2000 and 2022 using remote sensing techniques. The research employed Google Earth Engine and Landsat imagery to classify land use and land cover (LULC) changes. By analyzing annual cloud-free composites and employing random forest algorithms, the study produced detailed LULC maps, focusing on the 'infrastructure' class, which includes urban areas and major roads. Results indicate a significant 33% increase in infrastructure coverage, growing from approximately 380,000 hectares in 2000 to 510,000 hectares in 2022. This expansion was predominantly observed in seven regions, which accounted for 68% of the total infrastructure area and 83% of the national increase. A notable correlation (0.6) between urban growth and population growth was identified, suggesting that urban expansion is largely driven by demographic changes. However, regions with higher population growth exhibited more vertical urban development. The study highlights the complex interplay between urbanization, population dynamics, and regional planning, emphasizing the need for sustainable development strategies to manage urban growth effectively. Validation efforts showed high classification accuracies, with infrastructure class accuracies averaging 82% for the User and 87% for the Producer across the evaluated years.