Atmospheric Electricity Research Articles

Corrosion behavior and mechanism of 921 A high-strength low-alloy steel in harsh marine atmospheric environments

High-strength low-alloy 921 A steel faces significant corrosion challenges in harsh marine atmospheric conditions, threatening marine and energy industry safety. This study investigates the corrosion behavior of 921 A steel through accelerated tests in a specially developed multi-factor coupled corrosion chamber. Combining the multi-factor coupling cyclic corrosion test method with finite element numerical simulation, the long-term corrosion behavior can be accurately predicted, and the power function relationship between the corrosion rate and time of the test steel is obtained, which is expressed as C=0.2259 t–0.5182. Analysis identified α-FeOOH, Fe3O4, γ-FeOOH, Cl—, and Cr in corrosion layers. First-principles calculations and XPS analysis showed Cr oxidation inhibits Cl— adsorption and diffusion, highlighting the steel’s corrosion resistance. Finite element analysis and outdoor corrosion data confirmed the corrosion rate and time correlation, proving simulation reliability. This research provides crucial insights into 921 A steel’s corrosion resistance in marine environments, benefiting marine engineering.

Smart Lanceolate Surface with Fast Fog-Digesting Performance for Triboelectric Energy Harvesting.

Utilizing the ubiquitous fog in nature to create decentralized energy-harvesting devices, free from geographical and hydrological constraints, presents an opportunity to foster sustainable power generation. Extracting electrical energy from fog relies heavily on fog-digesting performance. Improving the efficiency of fogwater utilization remains a formidable challenge for existing fogwater energy-harvesting technologies. Inspired by the water-harvesting behavior of Tillandsia leaves, a smart lanceolate surface is developed to harvest triboelectric energy by rapidly digesting fog. Such a surface exhibits capabilities in fog management, encompassing precise fog capture, transportation, and critical droplet separation. Specifically, fog droplets condense at hydrophilic sites of acylated cellulose ester, subsequently migrating toward the rear under Laplace pressure, thereby producing energy as they traverse through the tail end. Such architecture yields a brief voltage restoration period (with an average of 9.36 s), can rush the capacitor to 11.59 V within 20 s, and achieves a water-digestion rate of up to 71.05 kg/m2 h. This biomimetic approach enhances the water-digestion efficacy of the atmospheric water energy apparatus and offers perspectives on mitigating deficiencies in power resources.

Observations of Locally Excited Waves in the Low Solar Atmosphere Using the Daniel K. Inouye Solar Telescope

We present an interpretation of the recent Daniel K. Inouye Solar Telescope (DKIST) observations of propagating wave fronts in the lower solar atmosphere. Using MPS/University of Chicago MHD radiative magnetohydrodynamic simulations spanning the solar photosphere, the overshoot region, and the lower chromosphere, we identify three acoustic-wave source mechanisms, each occur at a different atmospheric height. We synthesize the DKIST Visible Broadband Imager G-band, blue-continuum, and Ca ii K signatures of these waves at high spatial and temporal resolution, and conclude that the wave fronts observed by DKIST likely originate from acoustic sources at the top of the solar photosphere overshoot region and in the chromosphere proper. The overall importance of these local sources to the atmospheric energy and momentum budget of the solar atmosphere is unknown, but one of the excitation mechanisms identified (upward propagating shock interaction with down-welling chromospheric plasma resulting in acoustic radiation) may be an important shock dissipation mechanism. Additionally, the observed wave fronts may prove useful for ultralocal helioseismological inversions and promise to play an important diagnostic role at multiple atmospheric heights.

Tracing field lines that are reconnecting, or expanding, or both

The explosive release of energy in the solar atmosphere is driven magnetically, but the mechanisms that trigger the onset of the eruption remain controversial. In the case of flares and coronal mass ejections (CMEs), ideal or non-ideal instabilities usually occur in the corona, but it is difficult to obtain direct observations and diagnostics there. To overcome this difficulty, we analyze observational signatures in the upper chromosphere or transition region, particularly brightening and dimming at the base of coronal magnetic structures. In this paper, we examine the time evolution of spatially resolved light curves in two eruptive flares and identify a variety of tempo-spatial sequences of brightening and dimming, such as dimming followed by brightening and dimming preceded by brightening. These brightening–dimming sequences are indicative of the configuration of energy release in the form of plasma heating or bulk motion. We demonstrate the potential of using these analyses to diagnose the properties of magnetic reconnection and plasma expansion in the corona during the early stages of the eruption.

Sensitivity of the global hydrological cycle to the altitude of stratospheric sulphate aerosol layer

Abstract Stratospheric aerosol geoengineering (SAG) has been proposed as one of the potential options to offset the impacts of anthropogenically induced climate change. Previous modelling studies have shown that the efficacy of the cooling via SAG increases with altitude of the aerosol layer. It has been also shown that the stratospheric heating associated with SAG could stabilize the tropical atmosphere and weaken the tropical hydrological cycle. Using a global climate model, we perform a systematic study by prescribing volcanic sulphate aerosols at three different altitudes (22 km, 18 km and 16 km) and assess the sensitivity of the global and tropical mean precipitation to the altitude. We find that even though the efficacy of cooling increases with altitude of the aerosol layer, the global and tropical mean precipitation changes are less sensitive to the height of the aerosol layer. This is because the magnitude of both the global and tropical mean precipitation reduction increases with aerosol altitude in response to increasing efficacy of aerosols, but this sensitivity related to the slow response is nearly offset by the sensitivity of fast precipitation adjustments to aerosol altitude. A perspective and analysis based on atmospheric energy budget is presented to explain the lack of sensitivity of the hydrological cycle to the altitude of the stratospheric sulphate aerosol layer.

An Overview of the Role of Forests in Climate Change Mitigation

Nowadays, climate change is recognized as one of the biggest problems the world is facing, posing a potential threat to the environment and almost all aspects of human life. Since the United Nations Framework Convention on Climate Change in 1992, many efforts have been made to mitigate climate change, with no considerable results. According to climate change projections, temperatures will continue to rise, and extreme weather events will become more frequent, prolonged, and intense. Reflecting these concerns, the 2015 Paris Agreement was adopted as the cornerstone for reducing the impact of climate change, aiming to limit global warming below 2 °C and even keep the temperature rise below 1.5 °C. To achieve this international goal, focused mitigation actions will be required. Climate change has a strong impact on forests, enhancing their growth but also posing risks to them. Conversely, forests can mitigate climate change, as they have a considerable impact on global surface temperatures through their influence on the land–atmosphere energy exchange and the absorption of vast amounts of CO2 through photosynthesis. Consequently, afforestation and reforestation have become integral components of climate change mitigation strategies worldwide. This review aims to summarize the cutting-edge knowledge on the role of forests in climate change mitigation, emphasizing their carbon absorption and storage capacity. Overall, the impact of afforestation/reforestation on climate change mitigation hinges on strategic planning, implementation, and local forest conditions. Integrating afforestation and reforestation with other carbon removal technologies could enhance long-term effectiveness in carbon storage. Ultimately, effective climate change mitigation entails both restoring and establishing forests, alongside reducing greenhouse gas emissions.

Recent Advances of Bio-Based Hydrogel Derived Interfacial Evaporator for Sustainable Water and Collaborative Energy Storage Applications.

Solar interfacial evaporation strategy (SIES) has shown great potential to deal with water scarcity and energy crisis. Biobased hydrogel derived interfacial evaporator can realize efficient evaporation due to the unique structure- properties relationship. As such, increasing studies have focused on water treatment or even potential accompanying advanced energy storage applications with respect of efficiency and mechanism of bio-based hydrogel derived interfacial evaporation from microscale to molecular scale. In this review, the interrelationship between efficient interfacial evaporator and bio-based hydrogel is first presented. Then, special attention is paid on the inherent molecular characteristics of the biopolymer related to the up-to-date studies of promising biopolymers derived interfacial evaporator with the objective to showcase the unique superiority of biopolymer. In addition, the applications of the bio-based hydrogels are highlighted concerning the aspects including water desalination, water decontamination atmospheric water harvesting, energy storage and conversion. Finally, the challenges and future perspectives are given to unveil the bottleneck of the biobased hydrogel derived SIES in sustainable water and other energy storage applications.

The Zonal Seasonal Cycle of Tropical Precipitation: Introducing the Indo-Pacific Monsoonal Mode

Abstract The intertropical convergence zone (ITCZ) is associated with a zonal band of strong precipitation that migrates meridionally over the seasonal cycle. Tropical precipitation also migrates zonally, such as from the South Asian monsoon in Northern Hemisphere summer (JJA) to the precipitation maximum of the west Pacific in Northern Hemisphere winter (DJF). To explore this zonal movement in the Indo-Pacific sector, we analyze the seasonal cycle of tropical precipitation using a 2D energetic framework and study idealized atmosphere–ocean simulations with and without ocean dynamics. In the observed seasonal cycle, an atmospheric energy and precipitation anomaly forms over South Asia in northern spring and summer due to heating over land. It is then advected eastward into the west Pacific in northern autumn and remains there due to interactions with the Pacific cold tongue and equatorial easterlies. We interpret this phenomenon as a “monsoonal mode,” a zonally propagating moist energy anomaly of continental and seasonal scale. To understand the behavior of the monsoonal mode, we develop and explore an analytical model in which the monsoonal mode is advected by low-level winds, is sustained by interaction with the ocean, and decays due to the free tropospheric mixing of energy. Significance Statement Regional concentrations of tropical precipitation, such as the South Asian monsoon, provide water to billions of people. These features have strong seasonal cycles that have typically been framed in terms of meridional shifts of precipitation following the sun’s movement. Here, we study zonal shifts of tropical precipitation over the seasonal cycle in observations and idealized simulations. We find that land–ocean contrasts trigger a monsoon with concentrated precipitation over Asia in northern summer and near-surface eastward winds carry this precipitation into the west Pacific during northern autumn in what we call a “monsoonal mode.” This concentrated precipitation remains over the west Pacific during northern winter, as further migration is impeded by the cold sea surface temperatures (SSTs) and easterly winds of the east Pacific.

Eco-friendly triboelectric nanogenerator for self-powering stacked In2O3 nanosheets/PPy nanoparticles-based NO2 gas sensor

As atmospheric issues and energy crises worsen, developing environmentally friendly, low-cost, high-performance self-powered gas sensing systems for gas pollutant monitoring is crucial for the development of ecological civilization. In this work, an eco-friendly self-powered nitrogen dioxide (NO2) sensor (EFNS) system based on an eco-friendly triboelectric nanogenerator (EF-TENG) is reported. The system comprises a power supply unit (EF-TENG) and a sensing unit (In2O3/PPy sensor), connected through a signal stabilization circuit. EF-TENG utilizes eco-friendly and biodegradable gelatin and PLA/PBAT as the friction layer. By introducing leaf structures on the gelatin surface using a template method, the output voltage and current of EF-TENG were increased by 1.44 and 1.67 times, respectively. The peak power density and root mean square power density of EF-TENG reached 1386 mW m−2 and 185.35 mW m−2, respectively. Additionally, EF-TENG exhibited excellent long-term stability, maintaining a stable output voltage (∼24 V) after rectification and voltage stabilization treatment under conditions of 15–55°C and 40–80 % RH. Additionally, an In2O3/PPy heterostructure sensor was prepared, and the EFNS system was constructed through impedance matching effects, revealing the NO2 response mechanism of the In2O3/PPy heterostructure. This achieved a wide detection range and highly sensitive (Vg/Va = 355 %@30 ppm) detection of NO2. This work provides insights into eco-friendly self-powered gas sensors and sensing mechanisms, offering ideas for the development of environmental monitoring sensors and clean energy harvesting devices.

Negative Anomalies in the Atmospheric Electric Field near the Earth's Surface in Seismically Active Regions

The paper examines poorly-studied negative bay-like anomalies in the near-earth atmospheric electric field in seismically active regions at fair weather suitable for atmospheric electric observations. Observation data analysis revealed characteristic features of anomalies formation that allow us to conclude that the anomalies are associated with the deformation of near-surface rocks at tectonoseismic process. On the basis of the concept of atmospheric electricity, the source of anomalies in the electric field is a local negative space charge of small ions in the near-earth air emerged at a negative vertical gradient of electrical conductivity. It was revealed that the charge and produced negative anomalies in the electric field have deformation and emanation processes in their origin. We propose a scheme of anomalies formation and consider the role of radon and thoron in their emergence. It was found that thoron plays a more important role in some cases.

Statistical Analysis of Atmospheric Electrical Potential

Atmospheric electricity, a complex interplay between Earth's surface, atmosphere, and ionosphere, is driven by both the dramatic charge separation in thunderstorms and the continuous ionization by cosmic rays and radioactivity. This study investigates the variations in atmospheric electrical potential using statistical analysis of data collected in Ilorin, Nigeria. A copper arrester and an earth rod connected to a data logger continuously measured the air-ground potential difference for four months. Meteorological parameters (humidity and temperature) were also monitored. We analyzed the factors influencing atmospheric electrical potential variations and developed a predictive model based on the collected data. The model was validated with independent datasets. Results indicate a diurnal and seasonal pattern in atmospheric electrical potential, with peaks observed during evenings and winter months, and lows in afternoons and summer. atmospheric electrical potential exhibited a positive correlation with humidity and a negative correlation with temperature. This study highlights the complex and dynamic nature of atmospheric electrical potential, influenced by various local and global factors. These findings contribute valuable data and insights on atmospheric electrical potential, advancing scientific understanding in this field.

How Volcanic Aerosols Globally Inhibit Precipitation

AbstractVolcanic aerosols reduce global mean precipitation in the years after major eruptions, yet the mechanisms that produce this response have not been rigorously identified. Volcanic aerosols alter the atmosphere's energy balance, with precipitation changes being one pathway by which the atmosphere acts to return toward equilibrium. By examining the atmosphere's energy budget in climate model simulations using radiative kernels, we explain the global precipitation reduction as largely a consequence of Earth's surface cooling in response to volcanic aerosols reflecting incoming sunlight. These aerosols also directly add energy to the atmosphere by absorbing outgoing longwave radiation, which is a major cause of precipitation decline in the first post‐eruption year. We additionally identify factors limiting the post‐eruption precipitation decline, and provide evidence that our results are robust across climate models.

The biogeophysical impacts of land cover changes in Northern Hemisphere permafrost regions

The permafrost zone in the Northern Hemisphere has experienced substantial land cover changes (LCCs) in recent decades, resulting in significant impacts on climate and ecosystems by regulating land–atmosphere interactions, energy, water fluxes, and carbon exchange. However, the response of LCCs to climate change is highly variable, especially in terms of biogeophysical effects in high latitude regions. The goal of this study therefore is to quantify the biogeophysical effects of LCCs in Northern Hemisphere permafrost regions. We combine land cover and climate data and separate natural and biogeophysical impacts of LCCs to estimate the contribution on the surface and shallow soil temperatures. From 2001 to 2020, approximately 26 % of the permafrost zone experienced LCCs. LCCs caused a decrease in albedo (−0.15 ± 1.03 %) and an increase in snow depth (2.04 ± 31.96 cm), evapotranspiration (2.19 ± 11.37 mm), and surface heat flux (0.09 ± 1.36 W/m2), resulting in an increase in temperatures: 0.03 ± 0.42 K (surface temperature), 0.07 ± 0.46 K (0–10 cm soil temperature), 0.07 ± 0.45 K (10–100 cm soil temperature), and 0.06 ± 0.43 K (100–200 cm soil temperature), which could increase the risk of permafrost degradation. Seasonally, LCCs exacerbate the temperature difference between winter and summer. Albedo dominates surface temperature changes, with about 87.5 % of surface temperature changes coinciding with albedo changes. Soil temperatures are regulated by snowpack and surface heat fluxes, in addition to albedo.

Observation of atmospheric millimeter-wave discharges at 94 GHz and comparison with other microwave and millimeter-wave frequencies

This report describes an investigation by experimentation to elucidate atmospheric discharge plasma induced using a 50 kW millimeter-wave beam at 94 GHz. Millimeter-wave discharge plasma is useful for an ultraviolet light source, radioactive material detection, chemical decomposition, and beamed energy propulsion (BEP). The gyrotron used in this study is the “UT-94” with a frequency of 94 GHz and an output power of 100 kW, which was developed at the University of Tokyo specifically for BEP research. The 94 GHz frequency is promising for atmospheric energy beaming because of its low atmospheric attenuation, small beam divergence, and existing utilization track records in the atmosphere. This study experimentally investigated the relationship between the incident beam power density and propagation velocity of an ionization-wave front, which is particularly critical to thrust performance. In addition, the plasma structures were also clarified at 94 GHz and compared with other microwave and millimeter-wave frequencies, such as 28 GHz and those higher than 100 GHz. As a result, finer microscopic structure in the H–k plane was observed than those reported in earlier studies. Furthermore, we found a clear relation between structures and propagation velocities in terms of the electric field concentration of the incoming electromagnetic-waves.

Effects of irrigation‐induced surface thermodynamics changes on wind speed in the Heihe River basin, Northwest China

AbstractThe Heihe River Basin, located in Northwest China, serves as a major commodity grain base in China due to its state‐of‐the‐art irrigation system. The rapid increase in soil moisture caused by irrigation can alter the land–atmosphere energy fluxes and regulate regional climate. However, the effects and mechanisms of irrigation on wind speed related to thermodynamics remain unclear. Here, we carried out two 10‐year numerical simulations using the Weather Research and Forecast (WRF) model incorporating a real‐time irrigation scheme. By comparing the simulation differences (including and excluding irrigation), we found that irrigation significantly decreased the daily mean and maximum wind speed at 10 m above ground by 0.30 and 0.55 m·s−1, respectively, in the irrigated area during the growth season. Such surface wind slowdown could be explained by irrigation‐induced surface air cooling and, hence, intensifying atmospheric column stability, weakening turbulent momentum transport, as well as opposite‐to‐prevailing winds vector anomaly caused by increased southward pressure gradient. Meanwhile, we also found wind slowdown mainly occurs below 1100 m while acceleration effect above that level. It was highlighted that the surface wind slowdown effect of irrigation substantially improved the performance of the WRF model. Due to the surface wind slowdown effect of irrigation, the positive bias of daily mean and maximum wind speed simulated by the WRF model was reduced by 15.3% and 27.4%, respectively. Our findings implicate the potential importance of irrigation in improving the performance of climate models as well as in explaining the phenomenon of global stilling.

Propagation and Maintenance of the Quasi-Biweekly Oscillation over the Western North Pacific in Boreal Winter

Abstract This study investigates the propagation and maintenance mechanisms of the dominant intraseasonal oscillation over the western North Pacific in boreal winter, the quasi-biweekly oscillation (QBWO). The wintertime QBWO over the western North Pacific is characterized by the westward-northwestward movement from the tropical western Pacific to the western North Pacific and resembles the n = 1 equatorial Rossby wave. Its westward migration is primarily driven by the seasonal-mean zonal winds that advect vorticity anomalies in the lower–middle troposphere and moisture anomalies in the lower troposphere. Its northward movement is preconditioned by the vorticity dynamics of the beta effect, the low-level vertical moisture variation, and the local air–sea interaction. The latter involves the atmospheric forcing on the underlying ocean by changing the surface heat flux fluctuations and the sea surface temperature feedback on the low-level atmospheric instability. Its maintenance is primarily through atmospheric external energy sources from diabatic heating, which first generates eddy available potential energy and then converts it to eddy kinetic energy. Significance Statement Atmospheric quasi-biweekly oscillation (QBWO) is an important climate phenomenon over the western North Pacific in boreal winter. It can trigger significant influences both in the tropical and extratropical regions. Given the importance, it is necessary to investigate the propagation and maintenance mechanisms of the QBWO over the western North Pacific in boreal winter. The QBWO usually propagates northwestward from the tropical western Pacific to the western North Pacific. The westward propagation is driven by the seasonal mean zonal winds that advect vorticity anomalies in the lower–middle troposphere and moisture anomalies in the lower troposphere. The northward propagation is caused jointly by several processes, including the atmospheric forcing on the ocean via the surface heat flux fluctuations, the feedback of ocean on the low-level atmospheric instability, the vorticity dynamics of the beta effect, and the vertical variation of low-level moisture. In addition, converting from eddy available potential energy to eddy kinetic energy is essential in maintaining the QBWO’s development. The disclosure of these crucial processes deepens the dynamics of the QBWO over the western North Pacific in boreal winter.

Historical sensible-heat-flux variations key to predicting future hydrologic sensitivity

Under anthropogenic climate change (CC), the global hydrological cycle intensifies at a rate known as hydrologic sensitivity (HS). Global climate models (GCMs) exhibit substantial uncertainty in HS. Past work suggests that another form of HS, derived from internal climate variability (IV), is useful for constraining this uncertainty. However, these two forms of HS are weakly related. Here we show that decomposing HS under both CC and IV, based on the global energy budget, provides insight into the likely range of future HS. We find that sensible heat exchange between the atmosphere and ocean is not accounted for in the atmospheric energy budget under IV, masking the connection between HS under IV and CC. Removing this term, a closer relationship emerges. We use observations in conjunction with this relationship to suggest an upward shift in the likely range of future HS (66% confidence interval: 2.00–2.36 W m−2 K−1).

Quantifying reaction rates in methane oxidation: atomistic simulations at high temperature

This study presents a comprehensive analysis of methane oxidation at high temperatures (2500 K–3500 K)—a critical process in atmospheric chemistry and energy production. Employing reactive molecular dynamics simulations, the research bridges the knowledge gap in understanding the complex reaction networks at these elevated temperatures. Key features include the identification of intermediate species and the simplification of the reaction networks through advanced simulation and post-processing techniques. Another focus of the study is on employing the Arrhenius equation for nonlinear curve fitting to determine activation energy and pre-exponential factors for various reactions. The analysis reveals that, despite temperature variations, there are 121 common reactions among the reduced reaction systems. This discovery revealed the underlying consistency in methane oxidation pathways across a range of high temperatures. The results of this research are vital for enhancing current models of methane oxidation, particularly in the context of improving combustion processes and deepening our understanding of atmospheric dynamics involving methane.

Low-Level Liquid-Bearing Clouds Contribute to Seasonal Lower Atmosphere Stability and Surface Energy Forcing over a High-Mountain Watershed Environment

Abstract Measurements of atmospheric structure and surface energy budgets distributed along a high-altitude mountain watershed environment near Crested Butte, Colorado, from two separate, but coordinated, field campaigns, Surface Atmosphere Integrated field Laboratory (SAIL) and Study of Precipitation, the Lower Atmosphere, and Surface for Hydrometeorology (SPLASH), are analyzed. This study identifies similarities and differences in how clouds influence the radiative budget over one snow-free summer season (2022) and two snow-covered seasons (2021/22; 2022/23) for this alpine location. A relationship between lower-tropospheric stability stratification and longwave radiative flux from the presence or absence of clouds is identified. When low clouds persisted, often with signatures of supercooled liquid in winter, the lower troposphere experienced weaker stability, while radiatively clear skies that are less likely to be influenced by liquid droplets were associated with appreciably stronger lower-tropospheric stratification. Corresponding surface turbulent heat fluxes partitioned differently based upon the cloud–stability stratification regime derived from early morning radiosounding profiles. Combined with the differences in the radiative budget largely resulting from dramatic seasonal differences in surface albedo, the lower atmosphere stratification, surface energy budget, and near-surface thermodynamics are shown to be modified by the effective longwave radiative forcing of clouds. The diurnal evolution of thermodynamics and surface energy components varied depending on the early morning stratification state. Thus, the importance of quiescent versus synoptically active large-scale meteorology is hypothesized as a critical forcing for cloud properties and associated surface energy budget variations. The physical relationships between clouds, radiation, and stratification can provide a useful suite of metrics for process understanding and to evaluate numerical models in such an undersampled, highly complex terrain environment.

ITCZ Response to Disabling Parameterized Convection in Global Fixed‐SST GFDL‐AM4 Aquaplanet Simulations at 50 and 6 km Resolutions

AbstractAs the community increases climate model horizontal resolutions and experiments with removing moist convective parameterizations entirely, it is imperative to understand how these advances affect the InterTropical Convergence Zone (ITCZ). We investigate how the ITCZ responds to deactivating parameterized convection at two resolutions, 50 and 6 km, in fixed sea surface temperature, aquaplanet simulations with the NOAA GFDL AM4 atmospheric model. Disabling parameterized convection at 50 km resolution narrows the ITCZ and increases its precipitation minus evaporation (P–E) maximum by ∼78%, whereas at 6 km resolution doing so widens the ITCZ and decreases its P–E maximum by ∼50%. Using the column‐integrated moist static energy budget, we decompose these tropical P–E responses into contributions from changes in atmospheric energy input (AEI), gross moist stability, and gross moisture stratification. At 6 km, the ITCZ weakens due to increased gross moist stability. Disabling the convective parameterization at this finer resolution deepens the circulation, favoring more efficient poleward energy transport out of the deep tropics and reduced precipitation in the core of the ITCZ. Conversely, at 50 km the ITCZ strengthening is primarily driven by AEI, which in turn stems primarily from increased low cloud amount and thus longwave cloud radiative cooling in the Hadley cell subsiding branch. The Hadley circulation overturning intensifies to produce poleward energy fluxes that compensate the longwave cooling, yielding a stronger ITCZ. We further show that the low level diabatic heating profiles over the descending region are instrumental in understanding such diverse responses.