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The heritage of ancient buildings is an important part of the world’s history and culture, which has extremely rich historical–cultural value and artistic research value. Beijing has a large number of ancient palace buildings, and because of the age of their construction, many of them have problems with varying degrees of peeling and molding on the inner surfaces of the envelope. To solve the problems of damp interiors of palace buildings, a mathematical model of indoor heat and moisture transfer was established based on an ancient wooden palace building in Beijing. The model was validated by fitting the measured and simulated data. And the effects of outdoor relative humidity, soil moisture, wall moisture, and other factors on indoor heat and moisture transfer of ancient buildings were simulated and analyzed via the control variables method. The results showed that the measured and simulated data are within the error range, which verifies the accuracy of the model. And the simulation of indoor humidity matched the measured humidity. Thus, the simulation results were consistent with the actual situation. The variable trend of the relative humidity of the indoor environment with the outdoor humidity is inconsistent from plane to plane, i.e., it increases or remains constant with the increase in the outdoor humidity. Indoor ambient relative humidity increased with increasing wall moisture. And the indoor average temperature is 24.5 °C, and indoor relative humidity ranged between 87.4% and 92.4%. Soil moisture and wall moisture were the main factors affecting indoor relative humidity.

Global warming has changed both the amount of global precipitation and the atmospheric capacity to retain water. In this paper, a novel definition of the long‐term Capturability of Atmospheric Water (CAW) based on horizontal atmospheric water transport is proposed, describing the ability of a certain area to intercept and convert the atmospheric water transported by horizontal moisture flux into local precipitation. The significant decrease of the CAW in Amazon and Congo rainforests and Inside Greenland indicates that these areas were having less precipitation with the same water vapor in the past 42 years, while in Asia (especially China), CAW is showing a large‐scale increasing trend, verifying the regional humidifying. Considering the change of both the CAW and the background atmospheric water simultaneously, their mismatch degree is also investigated. The positive mismatch in Qinghai Tibet Plateau, Greenland, and the Andes, suggests higher susceptibility to climate change, and in the areas of negative mismatch (Amazon, Maritime Continent, southeastern China, the Eastern United States, India, and Japan), a more stable precipitation response to climate change is expected. The proposed concept of CAW provides a novel perspective to analyze the precipitation response to climate change on a global scale. Key Points A novel definition of long‐term Capturability of Atmospheric Water (CAW) based on horizontal transport is proposed In the past 42 years, the CAW in the Amazon and Congo rainforests and the Greenland ice sheet has degraded significantly The findings provide a perspective to analyze the precipitation response to global climate change

Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 30°–40°C temperature anomalies across the ice sheet. This record-shattering event saw numerous monthly temperature records being broken including a new all-time temperature record of −9.4°C on 18 March at Concordia Station despite March typically being a transition month to the Antarctic coreless winter. The driver for these temperature extremes was an intense atmospheric river advecting subtropical/midlatitude heat and moisture deep into the Antarctic interior. The scope of the temperature records spurred a large, diverse collaborative effort to study the heat wave’s meteorological drivers, impacts, and historical climate context. Here we focus on describing those temperature records along with the intricate meteorological drivers that led to the most intense atmospheric river observed over East Antarctica. These efforts describe the Rossby wave activity forced from intense tropical convection over the Indian Ocean. This led to an atmospheric river and warm conveyor belt intensification near the coastline, which reinforced atmospheric blocking deep into East Antarctica. The resulting moisture flux and upper-level warm-air advection eroded the typical surface temperature inversions over the ice sheet. At the peak of the heat wave, an area of 3.3 million km 2 in East Antarctica exceeded previous March monthly temperature records. Despite a temperature anomaly return time of about 100 years, a closer recurrence of such an event is possible under future climate projections. In Part II we describe the various impacts this extreme event had on the East Antarctic cryosphere.

Interactions between large-scale waves and the Hadley cell are examined using a linear two-layer model on an f plane. A linear meridional moisture gradient determines the strength of the idealized Hadley cell. The trade winds are in thermal wind balance with a weak temperature gradient (WTG). The mean meridional moisture gradient is unstable to synoptic-scale (horizontal scale of ∼1000 km) moisture modes that are advected westward by the trade winds, reminiscent of oceanic tropical depression–like waves. Meridional moisture advection causes the moisture modes to grow from “moisture-vortex instability” (MVI), resulting in a poleward eddy moisture flux that flattens the zonal-mean meridional moisture gradient, thereby weakening the Hadley cell. The amplification of waves at the expense of the zonal-mean meridional moisture gradient implies a downscale latent energy cascade. The eddy moisture flux is opposed by a regeneration of the meridional moisture gradient by the Hadley cell. These Hadley cell–moisture mode interactions are reminiscent of quasigeostrophic interactions, except that wave activity is due to column moisture variance rather than potential vorticity variance. The interactions can result in predator–prey cycles in moisture mode activity and Hadley cell strength that are akin to ITCZ breakdown. It is proposed that moisture modes are the tropical analog to midlatitude baroclinic waves. MVI is analogous to baroclinic instability, stirring latent energy in the same way that dry baroclinic eddies stir sensible heat. These results indicate that moisture modes stabilize the Hadley cell and may be as important as the latter in global energy transport.

A recent theory proposes that tropical depression (TD)‐type waves grow by flattening the mean meridional moisture gradient, consequently weakening the Hadley Cell through a poleward moisture flux. To evaluate this theory, we investigate the seasonality of TD‐type waves and their relation to the Hadley Cell in ERA5 and Coupled Model Intercomparison Project Phase 6 (CMIP6) models. On the basis of the theory, a Hadley Cell instability metric is defined whose variability is largely determined by the background meridional moisture gradient and the sensitivity of rainfall to moisture fluctuations. Results show that both TD‐type wave column moisture variance and eddy moisture fluxes peak when the Hadley Cell instability metric is a maximum. These conditions typically occur when the mean meridional precipitation gradient is strongest and the Hadley Cell is weak and narrow. CMIP6 models that exhibit higher Hadley Cell instability metric simulate stronger TD‐type wave activity in the Northern Hemisphere.

Precipitation and the atmospheric moisture budget are analyzed for 40-yr periods of recent and future climate simulated by the 10 CMIP6 models from which the vertically integrated moisture flux data are available. This allows new assessments of this important atmospheric transport, which can typically only be approximated. Seasonal climatological fields are compared with those from the ERA5 reanalysis. Using the four-season average M skill score for the globe, precipitation from the 10 models is similar in skill to that from a further 25 models. The scores for six moisture variables, including flux and its convergence, demonstrate global skill for each model. The 10-model average fields have better skill than any individual model. Changes are calculated for 2040–79 under the SSP5-8.5 forcing scenario. The focus is on the 10-model average scaled as a projection of change for a global warming of 2°C. The changes in precipitation, temperature, and pressure in each season are largely consistent with those from the larger ensemble. The changes in flux, convergence, water column, and winds at three levels are presented. The role of convergence in balancing precipitation changes over many land regions is evident. Flux, convergence, and precipitation are shown in detail for selected cases, including central North America, the South American monsoon, southern Africa in summer, southern South America in winter, Europe in summer, and both polar regions. Typically, flux is enhanced, but the associated convergence may shift. The production of the vertically integrated flux vector as a standard output from climate models is supported.

The intertropical convergence zone (ITCZ), with its twice-annual passage over central Africa, is considered as the main driver of the rainfall seasonality. In this ITCZ paradigm, high rainfall occurs over regions of large low-level convergence. But recently, this paradigm was challenged over central Africa. Here, we show that a shallow meridional overturning circulation—driven by surface conditions—plays a thermodynamical control on the rainfall seasonality over central Africa. Indeed, due to the local evaporative cooling effect, the foot of the ascending branch of Hadley cells occurs where the temperature is the warmest, indicating a thermal low. This distorts the southern Hadley cell by developing its bottom-heavy structure. As result, both shallow and deep Hadley cells coexist over central Africa year-round. The deep mode is associated with the poleward transport of atmospheric energy at upper levels. The shallow mode is characterized by a shallow meridional circulation, with its moisture transport vanishing and converging in the midtroposphere rather than at lower troposphere. This midtropospheric moisture convergence is also the dominant component that shapes the vertically integrated moisture flux convergence, with little contribution of African easterly jets. This convergence zone thus controls the precipitating convection. Its meridional migration highlights the interhemispheric rainfall contrast over central Africa and outlines the unimodal seasonality. On the other hand, forced by the Congo basin cell, the precipitable water regulates the deep convection from the vegetated surface of Congo basin, acting as a continental sea. This nonlinear mechanism separates the rainfall into three distinct regimes: the moisture-convergence-controlled regime, with convective rainfall exclusively occurring in the rainy season; the local evaporation-controlled regime with drizzle in the dry season; and the precipitable-water-controlled regime, with exponential rainfall increase in the dry season.

The coupling between soil moisture (SM) and evapotranspiration (ET) governs key dynamics of Earth's climate and biosphere productivity. Yet, prevailing statistical models fall short of capturing the physics of water–energy exchange across diverse hydroclimates. In this study, we introduce an optimal transport framework based on the hypothesis that hydroclimates regulate SM–ET coupling near a quasi‐optimum state. This state is characterized by least action principle, defined by dynamic convolution between the water potential gradient (Δω${\\Delta }\\omega $ ) driving land‐to‐atmosphere moisture flux and the time weighted mass flux (referred as the SM‐ET coupling metric, λSM−ET${\\lambda }_{SM-ET}$ ). Global validation of this framework using decadal (2010–2019) SM and ET remote sensing data reveals widespread convergence toward the least action state across hydroclimatic zones, supporting the notion of emergent climatic regulation in SM–ET coupling. As a corollary to the proposed hypothesis, we estimate two emergent properties of the SM–ET coupling: active root zone depth supporting ET, and the characteristic transit timescales over which SM is lost to atmosphere. Our root depth estimates show strong correspondence with in situ measurements (correlation >0.86) across biomes, underscoring the framework's physical realism. Notably, dynamic transit times are also validated against isotope measurements and findings suggest that SM perturbations often cycle back into the atmosphere within 3–7 days, calling into question traditional metrics of bulk residence time, that often overestimates the actual turnover. Overall, this framework provides a physically grounded way to study water–energy interactions across diverse environments.

Observations show a bimodal frequency distribution in total column vapor (TCV) over tropical oceans, with convective rainfall predominantly produced on the moist side of the frequency minimum between two modal peaks. Here we show a km–scale model of the tropics with explicit convection produces a bimodal TCV distribution, whereas the same model with parameterized convection does not. The parameterized model also fails to realistically confine rainfall to a moist mode. Using concepts from statistical mechanics we relate TCV frequency and tendency, and isolate process contributions to tendency in TCV phase‐space. Where bimodality is lacking, we find an incorrect relationship between moisture flux convergence and TCV in environments with little or no rainfall. The resulting lack of a strong gradient in TCV tendency with respect to TCV is inconsistent with that expected to maintain a TCV frequency minimum. Our results demonstrate value in the TCV distribution as a process diagnostic.

An approach to studying the processes of thermal treatment (heating, drying) of some types of polygraphic materials is proposed, which is based on the theory of nonstationary heat and mass transfer. The approach has been approbated for the process of conductive (contact) drying of a board sheet. The results of numerical investigations are applicable in practice in studying the processes of heat and moisture transfer in capillary-porous colloidal structures, as a result of which optimization of the technological regimes of drying-out and provision of the required qualitative characteristics of the products is possible for both polygraphic and other industrial areas.