Water Vapor Environment Research Articles

Acceleration of Environmentally Assisted Cracking Initiation of the Type 316L Steel in High-Temperature Water and Hydrogenated-Steam Vapor Environments

Environmentally assisted cracking of solution-annealed Type 316L austenitic stainless steel with two different surface treatments (polished versus ground) was investigated using the constant extension rate tensile test methodology in high-pressure water at 350°C and low-pressure H2-steam vapor at 350°C, 400°C, 440°C, and 480°C, while maintaining electrochemical corrosion potentials in the NiO stability regime. Flat tapered specimens were used to indentify the threshold stress for cracking (∼400 MPa) under these environmental conditions. Intensive oxidation and typical intergranular cracks were observed to initiate from the polished surface at 400°C and 440°C, whereas wavy cracks initiated on the ground surface. The results indicate that the ultrafine-grained layer formed adjacent to the ground surface effectively suppressed intergranular crack initiation under these test conditions. The slow loading under H2-steam vapor at 400°C under the oxidizing condition (NiO) was found to be a suitable high-accelerated test to study early stages of the cracking.

Quantitative µ-CT Analysis of Scale Topology Formed During Oxidation of High SiMo Cast Iron

High SiMo cast iron components in automotive exhaust systems are exposed to high-temperature oxidation over time. Quantitative analysis of formed oxide scale is therefore important for the assessment of a component durability. The brittle nature of multilayered scale and thermal stress limits capture of a true topology using traditional 2D destructive cut and polish methods. In this study, nondestructive high spatial-resolution 3D µCT analysis was performed on 2.90-mm-diameter oxidized specimens which permitted direct observation with 3.5 µm pixel resolution. The specimens were oxidized in three sequential time steps for a total 100 h at 700 °C and 800 °C in air and combustion gas atmospheres. A MATLAB-coded algorithm was used to quantify the topology, thickness variation in internal and external scale layers, and scale/metal interface unevenness. Scale topology was linked to oxidation temperature and gas atmosphere. A water vapor environment increases scale/metal interface unevenness and scale layer thickness irregularity which were related to an accelerated oxidation rate.

Promoting fine particle removal in double-tower cascade wet flue gas desulfurization system by flue gas temperature reduction

The emission of fine particles from coal-fired power plants could cause many environmental issues. To promote the fine particle removal in coal-fired flue gas, a process involving a double-tower cascade wet flue gas desulfurization system based on heterogeneous water vapor condensation via flue gas temperature reduction between two desulfurization towers is proposed. In the established supersaturated water vapor environment, fine particles could develop into lager condensational-droplets, and then be efficiently removed in the subsequent secondary tower. The results of numerical analysis for this proposed process indicated that it was feasible under most scenarios, and the experimental results showed that the removal efficiency of fine particles in all size ranges could be promoted. Furthermore, the effects of some key operating parameters were also studied, and the results indicated that the total removal efficiency would be promoted by 15–20% and the fine particle emission could be reduced by 30–40% in most cases.

Preliminary estimation of the detection possibilities of Ganymede’s water vapor environment with MAJIS

The exosphere of Ganymede is the interface region linking the moon’s icy surface to Jupiter’s magnetospheric environment. Its characterization is of key importance to achieve a full understanding of the ice alteration processes induced by the radiation environment. Several scientific instruments that will operate on board the upcoming Jupiter Icy Moons Explorer (JUICE) mission, selected by ESA in the context of its Cosmic Vision programme, have the potential to study Ganymede’s exosphere. Among them, the Moons And Jupiter Imaging Spectrometer (MAJIS) will have the chance to investigate the composition of the moon’s exospheric components and the emission of water molecules. The exospheric water density profile, as obtained from current models, is a crucial parameter for the estimation of the expected signal to noise ratio related to the actual measurement. In lack of an adequate number of Ganymede’s observations from past missions, there is a general difficulty in constraining current exosphere models which are based, in general, on different scenarios and considerations and often show large discrepancies in the estimated spatial distribution of the neutral environment. In this work, we make a preliminary estimation of the expected IR emission from exospheric water molecules, using different modelled density profiles, and we speculate on the possibility of JUICE/MAJIS to detect it. An exercise on the potential plume detection capabilities of MAJIS is also performed. The first necessary step for performing these calculations is a rough comparison of the existing models of Ganymede’s water vapor exosphere. We discuss the characteristics of the neutral environment as derived from different exospheric models available in literature, the role of the ion-surface interactions in the H2O exosphere generation, and the related implications also in view of future observations. We then use the model outputs to estimate different scenarios for the expected non-Local Thermal Equilibrium (non-LTE) emission from these molecules. The results of this study can be of help during the JUICE observation planning phase.

Environmental barrier coatings using low pressure plasma spray process

AbstractYb2Si2O7/Si bilayer environmental barrier coatings (EBCs) on SiC ceramic substrate were produced by low pressure plasma spray (LPPS) process. Phase composition, microstructure, and thermal durability of LPPS Yb2Si2O7/Si coating were investigated. XRD analysis indicated that the coating is mainly composed of Yb2Si2O7 with ~15.5v% Yb2SiO5 phases. The LPPS EBCs have a dense microstructure with porosity less than 4%. Adhesion strength measurement indicated the LPPS EBCs have an average adhesion strength of 29.1 ± 0.8 MPa. Furnace cycle test (FCT) on the coatings in air at 1316°C was performed and the test ran for 900 cycles and there was no coating spallation/failure for LPPS Yb2Si2O7/Si EBCs. The FCT results demonstrated the excellent thermal cycle durability of LPPS EBCs. Oxidation kinetics investigation of LPPS EBCs in flowing 90% H2O (g)+10% air at 1316°C showed that the thermally grown oxide (TGO) growth rate is close to the oxidation rate of pure Si in dry air and is significantly lower than that in water vapor environment. The LPPS process is promising in making highly durable Yb2Si2O7‐based dense EBCs by impeding diffusion and ingression of water vapor/O2.

A review of ultra-high temperature materials for thermal protection system

Ultra-High Temperature Materials (UHTMs) are at the base of entire aerospace industry; these high stable materials at temperatures exceeding 1600 °C are used to manage the heat shielding to protect vehicles and probes during the hypersonic flight through reentry trajectory against aerodynamic heating and reducing plasma surface interaction. Those materials are also recognized as Thermal Protection System Materials (TPSMs). The structural materials used during the high-temperature oxidizing environment are mainly limited to SiC, oxide ceramics, and composites. In addition to that, silicon-based ceramic has a maximum-use at 1700 °C approximately; as it is an active oxidation process over low temperature and water vapor environment condition. However, a great emphasis is required for developing structural materials in oxidation and rapid heating environment where the temperature is greater than 1700 °C. This review covers briefly all main types of Thermal Protection Systems (TPSs) and all the materials are used to fabricate them with the maximum operational temperatures. Also, it covers the promised UHTMs (SiC, ZrB2, HfB2, SiB6 and B4C) which are currently using for several aerospace applications, especially for TPS. Besides, it discusses the oxidation of SiC, B4C, SiB6, ZrB2 and HfB2. Therefore, the carbides and borides of the transition metals, Zr and Hf have a high-melting temperature and good stability in forming high-melting temperature oxides.

Thermochemical stability of Y2Si2O7 in high‐temperature water vapor

AbstractThe thermochemical stability of Y2Si2O7 was assessed in a high‐temperature high‐velocity water vapor environment to improve the understanding of the mechanisms that lead to SiO2 depletion. Spark plasma sintered Y2Si2O7 specimens were exposed in a steam‐jet furnace at 1000°C and 1200°C for 3‐250 hours, steam velocities of 131‐174 m/s and at 1 atm H2O pressure. These exposures resulted in the selective volatilization of SiO2 to form volatile Si(OH)4 and porous Y2SiO5. Microstructural evolution from fine rectangular pores at short times to larger rounded pores at longer times was observed. Mechanisms contributing to the overall depletion reaction kinetics were evaluated and include the interface reaction to form Y2SiO5 and Si(OH)4 (g), Y2SiO5 coarsening, development of tortuosity in the pore network and diffusion of H2O (g) and Si(OH)4 (g) through pores by molecular diffusion and/or Knudsen diffusion. SiO2 depletion was found to follow parabolic volatilization kinetics (kp = 0.38 µm2/h) at 1200°C indicating the reaction is limited by a diffusion process, most likely the outward diffusion of Si(OH)4 (g) through pores. Results are utilized to assess the viability of Y2Si2O7 and other rare‐earth silicates as environmental barrier coating (EBC) materials for SiC ceramic matrix composites (CMCs).

Water vapor corrosion behaviors of plasma sprayed RE2SiO5 (RE = Gd, Y, Er) coatings

In this work, the corrosion behaviors of plasma sprayed RE2SiO5 coatings (X1-Gd2SiO5, X2-Y2SiO5, X2-Er2SiO5) in water vapor environments were evaluated at 1400 °C. The microstructure evolution of the coatings was characterized by SEM, XRD, XPS, and EBSD. The results showed that the RE2O3 phase in the surface layer of the as-sprayed coatings disappeared. A layer composed of Gd4.67Si3O13, Y2SiO5 and Er2SiO5 was formed for the Gd2SiO5, Y2SiO5 and Er2SiO5 coatings, respectively. The corrosion layer of the Er2SiO5 coating was the thinnest among all the coatings. The corrosion mechanisms of the coatings were analyzed based on microstructure characters.

Nanocarbon Electrochemistry

Automated image recognition and analysis techniques were combined with liquid cell transmission electron microscopy to explore the oxidation kinetics of nanocrystalline Fe thin films in a water vapor environment. From in situ microscopy experiments, localized oxidation was observed to initiate in the film then propagate in an unsteady fashion, alternatingly arresting and progressing. The oxidation front propagation occurred via new oxidation sites initiating 10s of nm ahead of the existing front rather than through a continuous expansion mechanism. The oxidation rate was seen to be highly dependent on electron dose rate, with increasing electron dose rate accelerating the oxidation front propagation and increasing the density of oxidation initiation sites. The in situ experiments were also performed in diffraction space where it was seen that Fe2O3 was formed during oxidation. Coupling in situ microscopy with automated image analysis creates new opportunities for studying the early stages of localized corrosion by providing direct observation of oxidation propagation as well as quantification of the oxidation rates and rapid identification of byproducts.

Investigating local oxidation processes in Fe thin films in a water vapor environment by in situ liquid cell TEM

Automated image recognition and analysis techniques were combined with liquid cell transmission electron microscopy to explore the oxidation kinetics of nanocrystalline Fe thin films in a water vapor environment. From in situ microscopy experiments, localized oxidation was observed to initiate in the film then propagate in an unsteady fashion, alternatingly arresting and progressing. The oxidation front propagation occurred via new oxidation sites initiating 10s of nm ahead of the existing front rather than through a continuous expansion mechanism. The oxidation rate was seen to be highly dependent on electron dose rate, with increasing electron dose rate accelerating the oxidation front propagation and increasing the density of oxidation initiation sites. The in situ experiments were also performed in diffraction space where it was seen that Fe2O3 was formed during oxidation. Coupling in situ microscopy with automated image analysis creates new opportunities for studying the early stages of localized corrosion by providing direct observation of oxidation propagation as well as quantification of the oxidation rates and rapid identification of byproducts.

Degradation of a SiC‐SiC composite in water vapor environments

AbstractThe article examines degradation of a SiC‐based fiber composite containing Tyranno ZMI fibers in water vapor at elevated temperatures (800°C and 1100°C). Degradation is characterized through mechanical tests under cyclic and quasi‐static tensile loading in the near‐threshold regime, at stresses at or slightly above the matrix cracking limit. These tests are augmented by examinations of fracture surfaces and polished cross‐sections, measurements of fracture mirror radii, and measurements of interfacial debond toughness and sliding resistance. Degradation involves highly localized consumption of fibers through reactions of water vapor with the fibers and the BN coatings in regions adjacent to the few matrix cracks present at low stresses; the global hysteresis response and the average interfacial properties are minimally affected. Boria formed by oxidation of BN appears to play a fluxing role; it combines with silica on the fibers to form a non‐protective molten glass. Inhomogeneous fiber consumption leads to stress concentrations in the fibers and hence reduced fiber strength. Spatial variations in the degradation process occur at two length scales: at the macroscopic scale, because of cracking of the external CVI SiC overcoat and subsequent water ingress through the cracks, and at the tow‐scale, because of cracking of the CVI SiC around the tows. Parsing the kinetic processes over the two length scales remains a significant challenge.

Thermal modification of high moisture round logs in the environment of saturated water vapor with simultaneous predrying

The review of researches in the field of heat treatment of wood in Russia and abroad is carried out. The energy saving technology of thermal modification of high moisture round logs in the environment of saturated water vapor with simultaneous predrying is developed. The description of design of installation for realization of the offered technology is presented. The tests for determination of physical and chemical changes in wood during thermal modification were run. The results of tests and the regime parameters of conducting the process of thermal modification in the environment of water vapor for the purpose of receiving wood with the improved final characteristics are presented.

Effect of water vapour on morphology of the Si/Ti-rich phase at the interface between oxide layer and aluminide coating

Silicon-doped aluminide (Al–Si) coatings were prepared on IN738 superalloy by hot dip. The microstructure and oxidation performance of the Al–Si coatings was investigated at 1050 °C in air and air plus water vapour. Water vapour can significantly reduce the oxidation resistance of Al–Si coatings. The Kirkendall voids were formed under the oxide layer in water vapour environment. The formation of a continuous Si/Ti-rich (SiCr3/Si3Ti5 phases) phase below the oxide layer could possibly slow down the internal oxidation, which increased the coating’s oxidation resistance in air. In addition, the Si/Ti-rich phase was unstable in air plus water vapour atmosphere.

Influence of salinity and moisture on the threshold shear velocity of saline sand in the Qarhan Desert, Qaidam Basin of China: A wind tunnel experiment

Determination of the threshold shear velocity is essential for predicting sand transport, dust release and desertification. In this study, a wind tunnel experiment was conducted to evaluate the influence of salinity and moisture on the threshold shear velocity of saline sand. Saline sand samples (mean particle size of 164.50–186.08 µm and the total silt, clay and salt content of 0.80%–8.25%) were collected from three saline sand dunes (one barchan dune and two linear dunes) in the Qarhan Desert, Qaidam Basin of China. Original saline sand samples were placed in two experimental trays for wet and dry processing to simulate deliquescence and desiccation, respectively. Surface moisture content ranging from 0.30% to 1.90% was generated by the steam method so that the saline sand can absorb water in a saturated water vapor environment. The motion of sand particles was determined by the observers with a solid laser. The laser sheet (0.80 cm thick), which was emitted by the solid laser, horizontally covered the sand surface and was bound to the sand. Results show that the cohesion of saline sand results from a combination of salt and water. The threshold shear velocity increases exponentially with the increase in crust thickness for the linear sand dunes. There is a positive linear correlation between the original moisture content and relative threshold shear velocity. The threshold shear velocity of dewatered sand is greater than that of wet sand with the same original moisture content. Our results will provide valuable information about the sand transport of highly saline soil in the desert.

(Invited) MOCVD-Grown Ga2O3 Field Effect Transistors on Sapphire

Gallium oxide (Ga2O3) materials have bandgaps in the range of ~4.8 eV, competitive mobility (~100 cm2/Vs), and high breakdown fields in the range of ~8-9 MV/cm. This breakdown is significantly higher than GaN or SiC, which are commonly used in today’s power transistors. As a consequence, Ga2O3 has an exceptionally large Baliga’s figure of merit[1] of 3214 vs only 846 for GaN or 317 for SiC.[2] This makes Ga2O3 a leading candidate to address the ultra-high power market, >1 kW. The simplest approach is to grow Ga2O3 on a native Ga2O3 substrate; however, these substrates are still expensive and limited in wafer size. There is a desire to develop heteroepitaxy of Ga2O3 with sapphire being one of the most common substrate choices.[3] One the factors complicating this work has been the many polymorphs possible for Ga2O3: α-, β-, γ-, δ-, ε- and κ- phase have all been reported. Most of the heteroepitaxial devices reported to date have been based on a-Ga2O3 which undergoes a phase transition at higher temperatures that limits high temperature operation—a major issue for a power transistors. In this work we report the metal organic chemical vapor deposition (MOCVD) growth of n-type and p-type Ga2O3:Si on c-plane sapphire substrates. We use a commercial Axitron 200/4 RF horizontal-flow reactor with trimethylgallium (TMGa) as the gallium precursor, high purity deionized water as the oxygen precursor, and SiH4 gas as the dopant. Both p- and n-type doping can be achived via MOCVD using silicon as the primary dopant, but by varryign the doping conditions alternately p- or n-type material can be achieved. MOCVD is very favorable or growing Ga2O3 thin films at low cost with high reproducibility for eventual industrial scale production. The use of low cost sapphire substrates also lends itself to a potential cost as existing industrial-scale MOCVD reacords currently used to grow GaN for solid-state lighting could easily be adapted to grow Ga2O3. We have previously studied our MOCVD-grown films via transmission electron microscopy (TEM) and reported them to be κ-Ga2O3 (an analog of orthorhombic κ-Al2O3 with the space group of Pna21).[4] This phase is unique among MOCVD heteroepitaxial material in that high temperature annealing of these films show that these films are stable when annealed in a nitrogen and water vapor environment at temperatures up to 900 °C—only a slight broadening of the x-ray full-with a half-maximum (FWHM) occurs, with no phase transition. This is important for the operation of high power desity transistors. These layers are then fabricated into various metal oxide semiconductor field effect transistors (MOSFET). We report devices with both p- and n-channels. We tested the best n-channel devices at high temperature found them to be thermally stable at temperatures from room temperature all the way up to 250 °C. The best MOSFETS exhibited complete pinch-off at a gate voltage of −10V with an on-off ratio of 108 at a drain source voltage (VDS) of 100 V. The three-terminal breakdown voltage (Vbr) at the off state is as high as 390 V at a gate voltage (VG) of −30 V. The drain current (ID) and on/off ratio slightly decrease at high operating temperatures; however, the devices maintains an on/off ratio of >106 even at 250 °C. Furthermore, the maximum ID was maintained even after thermal cycling the device 10 times from 250 °C to room temperature, and it was observed that the on/off ratio of 108 at RT was fully recovered. These thermally-stable MOSFETs fabricated from Ga2O3:Si grown by MOCVD on c-plane sapphire demonstrate the potential of Ga2O3 for next generation high power device applications. [1] B. J. Baliga, "Power semiconductor device figure of merit for high-frequency applications," in IEEE Electron Device Letters, vol. 10, no. 10, pp. 455-457, Oct. 1989. [2] Michael A. Mastro,a Akito Kuramata,b,c Jacob Calkins,d Jihyun Kim,e Fan Ren,f,∗ and S. J. Peartong, “Opportunities and Future Directions for Ga2O3,” ECS Journal of Solid State Science and Technology, 6 (5) P356-P359 (2017). [3] Manijeh Razeghi, Ji-Hyeon Park, Ryan McClintock, Dimitris Pavlidis, Ferechteh H. Teherani, David J. Rogers, Brenden A. Magill, Giti A. Khodaparast, Yaobin Xu, Jinsong Wu, Vinayak P. Dravid, "A review of the growth, doping, and applications of Beta-Ga2O3 thin films," Proc. SPIE 10533, Oxide-based Materials and Devices IX, 105330R (14 March 2018) [4] Y. Xu, J. Park, Z. Yao, C. Wolverton, M. Razeghi, J. Wu, and V. P. Dravid, “Strain-Induced Metastable Phase Stabilization in Ga2O3 Thin Films,” ACS Appl. Mater. Interfaces, vol. 11, p. acsami.8b17731, 2019. Figure 1

Studies on corrosion behavior of a single-crystal superalloy and its sputtered nanocrystalline coatings with solid NaCl deposit in O2 + 38 vol.% H2O environment at 700 °C

Corrosion behavior of the N5 superalloy (Ni-7.0 Cr-6.2 Al-7.5 Co-5.0 W-1.5 Mo-6.5 Ta-3.0 Re) and two nanocrystalline coatings prepared by magnetron sputtering is investigated in chlorine and water vapor environment at 700 °C. The alloy shows low corrosion resistance. Its oxide scale spalls off readily and includes porous NiO outer layer and NiCr(Al)2O4 inner one. The nanocrystalline coating performs better. Its oxide scale consists of Al2O3, NiO and Ta2O5. Chlorination and/or oxidation of Ta ruined compactness of scale. The yttrium modified nanocrystalline coating provides the highest corrosion resistance. Its scale is exclusively alumina. Yttrium inhibits the outward diffusion of Ta.

Photocatalytic properties of CuO/(001)‐TiO2 composites synthesized by the vapor–thermal method

Composites of (001)‐face‐exposed TiO2 ((001)‐TiO2) and CuO were synthesized in water vapor environment at 250°C with various Cu/Ti molar ratios (RCu/Ti). The resulting CuO/(001)‐TiO2 composites were characterized using a variety of techniques. The synthesis under high‐temperature vapor allows close contact between CuO and (001)‐TiO2, which results in the formation of heterojunctions, as evidenced by the shift of valence band maximum towards the forbidden band of TiO2. An appropriate ratio of CuO can enhance the absorption of visible light and promote the separation of photogenerated carriers, which improve the photocatalytic performance. The degradation rate constant Kapp increased from 5.5 × 10−2 to 8.1 × 10−2 min−1 for RCu/Ti = 0.5. Additionally, the results showed that superoxide radicals (•O2−) play a major role in the photocatalytic degradation of methylene blue.

Water dynamics and thermal properties of tyramine-modified hyaluronic acid - Gelatin hydrogels

A new family of injectable hydrogels, enzymatically crosslinked from mixtures of tyramine conjugates of hyaluronic acid (HA) and gelatin (Gel) are characterized in terms of their molecular morphology, miscibility and water sorption ability by employing Field Emission Scanning Electron Microscopy, water sorption/desorption measurements and differential scanning calorimetry technique. The hydrogels were chemically crosslinked by reaction of the phenol groups of the tyramine in the presence of the enzyme horseradish peroxidase and a small amount of hydrogen peroxide. The water fraction in the microporous hydrogels, hw, was up to 0.68 being achieved by equilibration in environment of saturated water vapor. Our measurements reveal good miscibility between HA and Gel components in the whole hydration range studied and that the HA/Gel mixtures exhibit glass transition characteristics, water diffusion dynamics and equilibrium water contents that are independent of the composition. The intermolecular interactions have been found to be dependent on the hydration level and the mixtures behave like the Gel component for hw < 0.20 and like the HA for higher hydration levels. On the other hand, the appearance of gel-sol like transition in all mixtures, like in neat Gel component, points to nanoscale heterogeneities in the hydrogels and the existence of Gel-rich nanodomains. Calorimetric measurements on hydrogels at high hydration levels (hw > 0.40) show that they become partially crystallized at subzero temperatures and reveal that absorbed water molecules form, at least, two discrete forms of ice crystals. In the phase separated hydrogels, next to ice phase, a second phase of polymer/water homogeneous mixture with constant water fraction about 0.25 has been identified.

Improvement of Surface Passivation of Tunnel Oxide Passivated Contact Structure by Thermal Annealing in Mixture of Water Vapor and Nitrogen Environment

The effects of post‐crystallization annealing within various atmospheres on the surface passivation quality of tunnel oxide passivated contact (TOPCon) for crystalline silicon (c‐Si) solar cells are studied. The results provide an innovative method for improving the surface passivation of the as‐crystallized TOPCon structure by annealing at moderate temperatures ranging from 300 to 700 °C within a mixture of water vapor and nitrogen atmosphere. The wet nitrogen improves the implied open‐circuit voltages (iVoc) from 700–710 to ≈730 mV on average and reduces the single‐side reverse saturated recombination current density (J0) to 3.8 fA cm−2, which is much more effective than the so‐called forming‐gas annealing. In addition, the contact resistivity remains in low values of ≈5 mΩ cm2, ensuring its application in the high‐efficiency c‐Si solar cell. Secondary ion mass spectroscopy provides the evidence that the enhanced surface passivation by the water vapor annealing results from the hydrogen incorporation, which is logically believed to passivate the defects in the oxide and c‐Si interface region. This study proposes a simple and cost‐effective technique to improve the surface passivation of TOPCon structure, which is suitable for the high‐efficiency c‐Si solar‐cell manufacture.

A Study of the Characteristics of Vertical Cloud Base Height Distribution over Eastern China

Cloud is an important factor that affects weather and climate, and the vertical distribution of cloud determines its role in the atmospheric radiation transfer process. In this paper, the characteristics of different cloud types and their vertical cloud base height distributions over Eastern China are investigated with a four-year 2B-CLDCLASS-LIDAR product. The intercomparison of cloud base height distribution from ground-based lidar, CloudSat and CALIPSO measurements was studied with observations over the Hefei and Jinhua areas. The 2B-CLDCLASS-LIDAR product has the potential to uncover geographical and seasonal changes in cloud base height distribution over the Hefei area and Jinhua area, which may be beneficial for local climate models, although the CPR on CloudSat suffers from surface clutter or blind-zones. The results show that for non-precipitation cloud over the defined region (Eastern China), the occurrence frequencies of altocumulus, stratocumulus, and cirrus clouds are 29.4%, 21.0%, and 18.9%, respectively. The vertical occurrence frequencies of their cloud base heights are 0.5–8.5 km, below 3.5 km, and 5.5–17.0 km. The precipitation clouds are dominated by nimbostratus (48.4%), cumulus (17.9%), and deep convective clouds (24.2%), and their cloud base heights are all below 3.0 km. The cloud base height distributions have large differences below 3 km between the satellite measurement and ground-based measurement over Hefei site. Between the Hefei site and Jinhua site, the difference in cloud base height distribution measured by ground-based lidar is in good agreement with that measured by satellite over their matched grid boxes. Over the Hefei site, the vertical occurrence frequencies of cloud base height measured by ground-based lidar are higher than the satellite measurement within 0–0.5 km during all the seasons. It is suggested that more cloudy days may result from the sufficient water vapor environment in Hefei. In summer, the occurrence frequency of the cloud base height distribution at a height of 0–2.0 km is lower than other seasons over Jinhua city, which may be associated with the local weather system. Over the Jinhua site, the difference in seasonal cloud base height distribution based on satellite is in good agreement with that based on ground-based lidar. However, it does not appear over Hefei site. Thus, a multi-platform observation of cloud base height seems to be one of the essential ways for improvement in the observation of cloud macroscopic properties.