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Monitoring the dynamics of atmospheric CO2 is crucial for enhancing comprehension of the carbon cycle. Using column‐averaged dry‐air mole fraction of CO2 (XCO2) data collected by the Orbiting Carbon Observatory (OCO)‐2 and OCO‐3 satellites during 2020–2021, this study explored seasonal and diurnal variations in XCO2 characteristics in typical land cover biomes in China, and investigated their relationships with meteorological drivers. Results showed that XCO2 products retrieved by OCO‐2 and OCO‐3 have good agreement with Total Carbon Column Observing Network measurements, with average deviations of 0.8 and 1.2 ppm, respectively. The satellite observations revealed XCO2 hotpots located mainly in central and eastern China, and areas of low XCO2 values in western China, with a seasonal curve that was highest (lowest) in spring (summer). The largest seasonal cycle amplitude (∼9 ppm) of XCO2 was observed in forest areas, highlighting its key role in carbon exchange. Additionally, XCO2 was found to have a near‐sinusoidal diurnal pattern, characterized by rapid decrease in the early morning as photosynthesis resumed after sunrise, as indicated by the sun‐induced chlorophyll fluorescence (SIF), a peak at around midday, and subsequent decrease as SIF increased after mid‐afternoon. Urban regions had the highest diurnal cycle amplitude (∼6 ppm) among biomes. Statistical analyses revealed seasonal shift and nonlinear variation in the relationships between XCO2 and meteorological variables, suggesting that CO2 uptake is influenced by favorable humidity conditions. These relationships also provide insight into the sensitivity and adaptability of XCO2 to meteorological factors in diverse ecosystems such as savanna and grassland. Plain Language Summary: Measuring CO2 concentrations helps us gain better understanding of the carbon cycle in the context of climate change. China is among the world's main emitters of carbon and it has pledged to achieve carbon neutrality. To create effective strategies for the mitigation of atmospheric CO2, it is important to investigate the CO2 dynamics on multiple time scales. Using observations from the OCO‐2 and OCO‐3 carbon‐monitoring satellites, we characterized the seasonal and diurnal variations in column‐averaged abundance of CO2 (XCO2) across biomes and examined the impact of meteorological factors. Our findings revealed a near‐sinusoidal pattern in the hourly variation of XCO2 over biomes, and suggested XCO2 seasonal variability varies among them, with maximum seasonal variability for forests (∼9 ppm), and the maximum diurnal variability for urban regions (∼6 ppm). Furthermore, meteorological, and photosynthetic activity indicated the complicated relationships with XCO2. Future carbon research efforts should consider the differences in the magnitude of CO2 variation among biomes and the complex effects of meteorological conditions. Key Points: OCO‐3 detects diurnal variations in XCO2 that follow a near‐sinusoidal patternMeteorological factors affect XCO2 seasonally and nonlinearlyVegetation activity should be observed to understand carbon cycles [ABSTRACT FROM AUTHOR]

Metal halide perovskite nanocrystals (PeNCs) are emerging as one of the most promising materials for optoelectrical devices such as light‐emitting diode (LED) owing to their tunable band gaps, high color purity, and tolerance to defects. Nevertheless, the materials have not yet demonstrated their full potential in practical applications due to the poor stability of PeNCs and their unsatisfactory performance in devices. In this research, LED devices based on CsPbBr3 NCs are successfully demonstrated as an active light‐emitting layer with enhanced efficiency via potassium doping. The study of the effect of potassium dopant on physicochemical properties of inorganic CsPbBr3 PeNCs shows that potassium cations (K+) remain in the crystal structure of perovskite compound as interstitial defects, which results in better coverage of surface ligands on the PeNCs and improved energy band alignment with adjacent electron injection layer (2,2′,2′‐(1,3,5‐benzinetriyl)‐tris(1‐phenyl‐1‐H‐benzimidazole)) and hole injection layer (poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate) in an LED. As a consequence, the green LED with the K‐doped CsPbBr3 PeNCs shows luminance up to 5759 cd m‐2 and external quantum efficiency (EQE) of 5.6%, which is superior to the pristine device without K‐doping (luminance: 4579 cd m‐2, EQE: 4.8%). [ABSTRACT FROM AUTHOR]

The climatological characteristics of total aerosol optical thickness (AOT) together with fine and coarse mode AOT (fAOT and cAOT) and fine mode fraction (FMF = fAOT/AOT) over East and South Asia are presented here for the period March 2005 to October 2013. The characteristics are retrieved from POLDER/PARASOL measurements using recently developed aerosol component module of GRASP algorithm. The satellite retrievals were validated and presented a good agreement with the AERONET products (e.g., R of ~0.8–0.9 for AOT, fAOT, Ångström exponent, and FMF). The results show a seasonal cycle and strong relation to the emission sources. For example, FMF has a peak of nearly 1.0 in March in the Indo‐China Peninsula region, reaching a minimum of about 0.4 in April in Northwestern China region. These patterns can be explained by dominance of anthropogenic pollution or desert dust emissions. Maps of fine, coarse, and total AOT, as well as of FMF for the East and South Asia region, are presented and analyzed in scope of seasonal and interannual variabilities. Key Points: Aerosol optical thickness (AOT), fine mode AOT (fAOT), and coarse mode AOT (cAOT) are retrieved simultaneously by the component algorithmThe satellite retrieved aerosol optical properties show a good agreement with AERONET products in AsiaThe climatological characteristics of AOT, fAOT, cAOT, and fine mode fraction (FMF) over East and South Asia are presented [ABSTRACT FROM AUTHOR]

Accurate estimation of the spatiotemporal variations of solar radiation is crucial for assessing and utilizing solar energy, one of the fastest‐growing and most important clean and renewable resources. Based on observations from 2,379 meteorological stations along with scare solar radiation observations, the random forest (RF) model is employed to construct a high‐density network of daily global solar radiation (DGSR) and its spatiotemporal variations in China. The RF‐estimated DGSR is in good agreement with site observations across China, with an overall correlation coefficient (R) of 0.95, root‐mean‐square error of 2.34 MJ/m2, and mean bias of −0.04 MJ/m2. The geographical distributions of R values, root‐mean‐square error, and mean bias values indicate that the RF model has high predictive performance in estimating DGSR under different climatic and geographic conditions across China. The RF model further reveals that daily sunshine duration, daily maximum land surface temperature, and day of year play dominant roles in determining DGSR across China. In addition, compared with other models, the RF model exhibits a more accurate estimation performance for DGSR. Using the RF model framework at the national scale allows the establishment of a high‐resolution DGSR network, which can not only be used to effectively evaluate the long‐term change in solar radiation but also serve as a potential resource to rationally and continually utilize solar energy.Key Points: The RF model exhibits high accuracy and considerable potential in projecting DGSRImportance of possible variables for estimating DGSR is identified by the RF modelSpatiotemporal variations of DGSR across China are constructed from high‐density meteorological observations [ABSTRACT FROM AUTHOR]

The accuracy of the Atmospheric Infrared Sounder (AIRS) water vapor product in China is as yet unknown due to the lack of collocated in situ sounding observations. Based on high‐resolution soundings at 1400 Beijing time from 113 radiosonde sites across China, along with the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Global Positioning System (GPS) data sets, a preliminary assessment has been conducted of AIRS water vapor mixing ratio (q) and precipitable water vapor (PWV) products in June 2013 and June 2014. Comparison between AIRS and radiosonde data suggests that the correlation coefficient (R) and mean bias of these two q products in China exhibit a distinct geographical dependence (with the highest R values in northwest China). This suggests that the AIRS q product tends to be underestimated in southeast China where cloud cover prevails, but overestimated in northwest China where cloud cover is sparse. With regard to the height‐resolved distribution, the q products from both AIRS and radiosondes tend to decrease with increasing altitude, irrespective of the particular region. The spatial distribution of AIRS PWV is consistent with that from radiosonde‐derived PWV, except in south China where the AIRS PWV data set is considerably underestimated. The accuracy of the AIRS water vapor product tends to be impaired under highly cloudy conditions, corroborating the notion of clouds affecting the retrieval of AIRS PWV. Our findings highlight the importance of afternoon sounding measurements in validating AIRS data and call for the improved understanding of the role of water vapor in the context of global climate change. Key Points: Preliminary assessment of AIRS water products were performed in China based on radiosonde measurements at 1400 Beijing TimeAIRS water vapor mixing ratio is underestimated in southeast China, but overestimated in northwest ChinaClouds significantly affect the accuracy of AIRS water vapor products [ABSTRACT FROM AUTHOR]

Selective catalytic reduction (SCR) of NO by NH3 on iron‐based catalysts was investigated with a magnetically fluidized bed (MFB). Magnetic fields promoted the NO conversion. The optimal efficiency of 95 % was attained under a magnetic field of 0.01–0.015 T at 250 °C. Magnetic fields yielded transport effects and chemical effects on SCR of NO over Fe2O3 catalyst. The transport effects are reflected by the enhancement of physical transfer in a MFB. Magnetic fields can check and eliminate bubbles, increase gas‐solid contact probabilities, and thereby improve heat and mass transfer characteristics in a MFB. The chemical effects can be summarized into three points. First, the magnetization of γ‐Fe2O3 by uniform magnetic fields gives rise to boundary effects, which results in Faraday force on paramagnetic NO molecules and yields NO movement to the catalyst surface, and hence increases NO chemisorption. Second, the synergy of magnetic fields and ferrimagnetic iron‐based catalyst can boost the transformation of antimagnetic reactant into paramagnetic products, and accelerate electron transport in the reaction, which enhances the activation of NH3 on magnetic Fe (III) sites. Third, magnetic fields can alter the energy dispersal of a free radicals reaction system, and thereby promotes the free radicals reaction between NH2· and NO·. [ABSTRACT FROM AUTHOR]

Aerosol microphysical and optical properties as well as aerosol direct radiative effect (ADRE) were measured at a few ground sites to investigate aerosol optical‐radiative characteristics in northeastern China. Bimodal size distributions showed a dominance of fine mode particles at Shenyang, a megacity, and more impacts from larger particles at Fushun and Dalian, industrial and coastal sites, respectively. High aerosol optical depths at 440 nm in July (0.67–1.25) were ascribed to hygroscopic effects or cloud processing. Single scattering albedos at 440 nm show strong to moderate absorption at the urban and industrial sites (0.84–0.86) and weaker absorption at the coastal and rural sites (0.92–0.94). The single scattering albedo wavelength dependence implied influences of dust at the urban, industrial, and coastal regions (shorter wavelengths) and biomass emissions at the rural site (longer wavelengths). Absorptive aerosol optical depths at the urban and industrial sites were ~2.5 and 3.7 times higher than at the coastal and rural sites. Large negative ADREs at the bottom of the atmosphere at the urban and industrial sites implied strong surface cooling and the larger ADREs at the top of the atmosphere at the coastal site indicated more cooling of the Earth‐atmosphere system. The main aerosol types at the urban and industrial sites were mixed absorbing particles, while weakly‐absorbing fine mode particles dominated the coastal and rural sites. This study provides new information on the aerosol distributions and potential regional climate effects of aerosols in northeastern China. Key Points: High AODs in July were ascribed to hygroscopic effects in Northeast ChinaThe SSA440 nm show strong to slight absorption over the study regionThere is stronger surface cooling effect at the urban and industrial sites [ABSTRACT FROM AUTHOR]