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Advances in Atmospheric Sciences 2021年第8期38卷 1334-1350页

作者： Bo LIU juan huo Daren LYU Xin WANG Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

The accuracy of passive satellite cloud top height (CTH) retrieval shows regional dependence. This paper assesses the CTH derived from the FY-4A and Himawari-8 satellites through comparison with those from the ground-based millimeter radar at two sites: Yangbajing, Tibet, China (YBJ), and the Institute of Atmospheric Physics (IAP), Beijing, China. The comparison shows that Himawari-8 missed more CTHs at night than FY-4A, especially at YBJ. It is found that the CTH difference (CTHD;radar CTH minus satellite CTH) for FY-4A and Himawari-8 is 0.06 ± 1.90 km and −0.02 ± 2.40 km at YBJ respectively, and that is 0.93 ± 2.24 km and 0.99 ± 2.37 km at IAP respectively. The discrepancy between the satellites and radar at IAP is larger than that at YBJ. Both satellites show better performance for mid-level and low-level clouds than for high-level clouds at the two sites. The retrievals from FY-4A agree well with those from Himawari-8, with a mean difference of 0.08 km at YBJ and 0.06 km at IAP. It is found that the CTHD decreases as the cloud depth increases at both sites. However, the CTHD has no obvious dependence on cloud layers and fractions. Investigations show that aerosol concentration has little impact on the CTHD. For high and thin clouds, the CTHD increases gradually with the increase of the surface temperature, which might be a key factor causing the regional discrepancy between IAP and YBJ.

关键词： cloud top height Tibet millimeter radar FY-4A Himawari-8

Impact of cloud inhomogeneity on bi-directional reflectance

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Chinese Science Bulletin 2008年第1期53卷 124-130页

作者： WANG Yue LU DaRen huo juan Laboratory for Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

This paper uses SHDOM (Spherical Harmonics Discrete Ordinate Method) to calculate the nadir bidi-rectional reflectance distribution function (BRDF) of the cumulus and stratocumulus fields at the wave-lengths of 0.67 μm and 2.13μm, and discusses the impact of cloud inhomogeneity on BRDF. The cloud fields are adopted from I3RC Phase II, which are used to compare 3D radiative transfer models. The simulation results show that the cu field has 6% abnormal BRDF values (BRDF>1) with the increase of solar zenith angle. Further analyses show that grid cells whose BRDF is greater than one gather to-gether at the local trough of the top of cloud. These regions can receive not only the direct incident solar beam, but also the beam scattered by the higher cloud of its neighborhood. Hence, the BRDF of those regions is enhanced. The abnormal BRDF phenomenon shows that the cloud inhomogeneity can result in inconsistency between satellite observation and plane parallel theory, implying that the re-flectance observed by high resolution satellite is maybe enhanced by the cloud 3D effects. Thus one should take this fact into account when using the product retrieved by these data. The dominant solar zenith angles are quite large in the mid-high altitude area, and the impact of cloud inhomogeneity on these areas may be more significant.

关键词：云层反射率方向分布函数

Cloud Classification and Distribution of Cloud Types in Beijing Using Ka-Band Radar Data

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Advances in Atmospheric Sciences 2019年第8期36卷 793-803页

作者： juan huo Yongheng BI Daren Lü Shu DUAN Key Laboratory for Atmosphere and Global Environment Observation Chinese Academy of Sciences

A cloud clustering and classification algorithm is developed for a ground-based Ka-band radar system in the vertically pointing mode. Cloud profiles are grouped based on the combination of a time–height clustering method and the k-means clustering method. The cloud classification algorithm, developed using a fuzzy logic method, uses nine physical parameters to classify clouds into nine types: cirrostratus, cirrocumulus, altocumulus, altostratus, stratus, stratocumulus, nimbostratus,cumulus or cumulonimbus. The performance of the clustering and classification algorithm is presented by comparison with all-sky images taken from January to June 2014. Overall, 92% of the cloud profiles are clustered successfully and the agreement in classification between the radar system and the all-sky imager is 87%. The distribution of cloud types in Beijing from January 2014 to December 2017 is studied based on the clustering and classification algorithm. The statistics show that cirrostratus clouds have the highest occurrence frequency(24%) among the nine cloud types. High-level clouds have the maximum occurrence frequency and low-level clouds the minimum occurrence frequency.

关键词： clouds clustering algorithm classification algorithm radar cloud type

Anomalous pattern of ocean heat content during different phases of the solar cycle in the tropical Pacific

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Atmospheric and Oceanic Science Letters 2017年第1期10卷 9-16页

作者： huo Wen-juan XIAO Zi-Niu State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China College of Earth Science University of Chinese Academy of Sciences Beijing China

Solar radiation is a forcing of the climate system with a quasi-11-year *** a quasi-period forcing,the influence of the phase of the solar cycle on the ocean system is an interesting topic of *** this paper,the authors investigate a particular feature,the ocean heat content（OHC）anomaly,in different phases of the total solar irradiance（TSI） *** results show that almost opposite spatial patterns appear in the tropical Pacific during the ascending and declining phases of the TSI *** analysis reveals the presence of the quasi-decadal（11-year） solar signal in the SST,OHC and surface zonal wind anomaly field over the tropical Pacific with a high level of statistical confidence（95%）.It is noted that the maximum centers of the ocean temperature anomaly are trapped in the upper ocean above the main pycnocline,in which the variations of OHC are related closely with zonal wind and ocean currents.

关键词： Ocean heat content anomaly total solar irradiance solar cycle tropical Pacific

Application of cloud multi-spectral radiances in revealing cloud physical structures

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Earth and Planetary Physics 2019年第2期3卷 126-135页

作者： juan huo DaRen Lu WenJing Xu Key Laboratory for Atmosphere and Global Environment Observation Chinese Academy of Sciences

The radiances scattered or emitted by clouds demonstrate diverse features at different wavelengths due to different cloud physical structures. This paper presents a method(the smallest-radiance-distance method, SRaDM) of revealing the physical structures of clouds. The method is based on multi-spectral radiances measured by the Moderate Resolution Imaging Spectroradiometer(MODIS)onboard Aqua. The principle and methodology of SRaDM is deduced and provided in this paper. Correlation analysis based on data from MODIS and Cloud Profiling Radar(onboard CloudSat), collected from January 2007 to December 2010 over an ocean area(15°N–45°N,145°E–165°E), led to selection of radiances at 13 wavebands of MODIS that demonstrated high sensitivity to cloud physical structures;radiances at the selected wavebands were subjected to SRaDM. The Standardized Euclidean distance is introduced to quantify the degree of changes in multi-spectral radiances(termed D_(rd)) and in physical structures(termed D_(st)) between cloud profiles. Statistics based on numerous cloud profiles show that D_(rd) decreases monotonically with a decrease in D_(st), which implies that small D_(rd) always accompanies small D_(st). According to the law of D_(rd) and D_(st), the new method, SRaDM, for revealing physical structures of clouds from the collocation of cloud profiles of similar multi-spectral radiances, is presented. Then, two successful experiments are presented in which cloud physical structures are captured using multi-spectral radiances. SRaDM provides a way to obtain knowledge of the physical structures of clouds over relatively larger areas, and is a new approach to obtaining 3D cloud fields.

关键词： cloud physical structure radiance radar

The impact of solar activity on the 2015/16 El Ni?o event

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Atmospheric and Oceanic Science Letters 2016年第6期9卷 428-435页

作者： huo Wen-juan XIAO Zi-Niu State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina College of Earth Science University of Chinese Academy of SciencesBeijingChina

Recent SST and atmospheric circulation anomaly data suggest that the 2015/16 El Nino event is quickly decaying. Some researchers have predicted a forthcoming La Nina event in late summer or early fall 2016. From the perspective of the modulation of tropical SST by solar activity, the authors studied the evolution of the 2015/16 El Nino event, which occurred right after the 2014 solar peak year. Based on statistical and composite analysis, a significant positive correlation was found between sunspot number index and El Ni^o Modoki index, with a lag of two years. A clear evolution of El Nino Modoki events was found within 1-3 years following each solar peak year during the past 126 years, suggesting that anomalously strong solar activity during solar peak periods favors the triggering of an El Nino Modoki event. The patterns of seasonal mean SST and wind anomalies since 2014 are more like a mixture of two types of El Nino （i.e. eastern Pacific El Nino and El Nino Modoki）, which is similar to the pattern modulated by solar activity during the years following a solar peak. Therefore, the El Nino Modoki component in the 2015/16 El Nino event may be a consequence of solar activity, which probably will not decay as quickly as the eastern Pacific El Nino component. The positive SST anomaly will probably sustain in the central equatorial Pacific （around the dateline） and the northeastern Pacific along the coast of North America, with a low-intensity level, during the second half of 2016.

关键词： El Nino El Nino Modoki solaractivity SST atmospheric circulation

Last but not the least: effects of laying sequence on egg color variation and embryonic development of Russet Sparrow(Passer cinnamomeus)

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Avian Research 2018年第3期9卷 198-205页

作者： juan huo Tongping Su Nan Niu Canchao Yang Wei Liang Ministry of Education Key Laboratory for Ecology of Tropical Islands College of Life Sciences Hainan Normal University College of Forestry Guangxi University

Background: Laying sequence has important effects on eggshell color and embryonic development in birds. Some birds can allocate resources unevenly among the eggs within a clutch, prioritizing those at the beginning of the laying sequence, in order to maximize reproductive success. The changes in egg color according to laying sequence may be an adaptation to pressure from predators or brood ***: In this study, effects of laying sequence on egg color and embryonic heart rate in Russet Sparrows(Passer cinnamomeus) were investigated using artificial nest boxes. The eggs were divided into three groups: first to be laid, intermediate in the laying sequence, and last to be laid. We maintained the eggs in an incubator and measured embryonic heart ***: Avian visual modeling showed that the background color brightness of the last eggs laid was significantly higher(whiter) than those of the other eggs. All eggs were about the same size and hatched around 13 days, indicating that laying sequence significantly affected embryonic development speed; the last eggs to be laid developed significantly faster than did the first in the ***: Our study quantified the effect of laying sequence on egg color variation and proved that laying sequence has an important effect on embryonic heart rate in Russet Sparrows.

关键词： Egg color variation Egg color quantification Embryonic development Fiber optic spectrometer Laying sequence Russet Sparrow

Antioxidant axis Nrf2-keap1-ARE in inhibition of alcoholic liver fibrosis by IL-22

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World Journal of Gastroenterology 2017年第11期23卷 2002-2011页

作者： Ya-Hui Ni Li-juan huo Ting-Ting Li Department of Gastroenterology First Hospital of Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina

AIM To explore the effect of interleukin(IL)-22 on in vitro model of alcoholic liver fibrosis hepatic stellate cells(HSCs), and whether this is related to regulation of *** HSC-T6 cells were incubated with 25, 50, 100, 200 and 400 μmol/L acetaldehyde. After 24 and 48 h, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay was used to detect proliferation of HSCs to choose the best concentration and action time. We used the optimal concentration of acetaldehyde(200 μmol/L) to stimulate HSCs for 24 h, and treated the cells with a final concentration of 10, 20 or 50 ng/m L IL-22. The cell proliferation rate was detected by MTT assay. The cell cycle was analyzed by flow cytometry. The expression of nuclear factor-related factor(Nrf)2 and α-smooth muscle antigen was detected by western blotting and immunocytochemistry. The levels of malondialdehyde(MDA) and glutathione(GSH) were measured by spectrophotometry. RESULTS In the MTT assay, when HSCs were incubated with acetaldehyde, activity and proliferation were higher than in the control group, and were most obvious after 48 h treatment with 200 μmol/L acetaldehyde. The number of cells in G0/G1 phases was decreased and the number in S phase was increased in comparison with the control group. When treated with different concentrations of IL-22, HSC-T6 cell activity and proliferation rate were markedly decreased in a dosedependent manner, and cell cycle progression was arrested from G1 to S phase. Western blotting and immunocytochemistry demonstrated that expression of Nrf2 total protein was not significantly affected. Expression of Nrf2 nuclear protein was low in thecontrol group, increased slightly in the model group(or acetaldehyde-stimulated group), and increased more obviously in the IL-22 intervention groups. The levels of MDA and GSH in the model group were significantly enhanced in comparison with those in the control group. In cells treated with IL-22, the MDA level was attenuat

关键词： Interleukin-22 Alcoholic liver fibrosis Hepatic stellate cells Nrf2 Oxidative stress

Russet Sparrows spot alien chicks from their nests

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Avian Research 2018年第2期9卷 150-156页

作者： juan huo Canchao Yang Tongping Su Wei Liang Anders Pape Moller Ministry of Education Key Laboratory for Ecology of Tropical Islands College of Life Sciences Hainan Normal University Haikou 571158 China College of Forestry Guangxi University Nanning 530004 China Ecologie Systematique Evolution Universite Paris-Sud CNRS Agro Paris Tech Universite Paris Saclay 91405 Orsay Cedex France

Background： In coevolutionary interactions between brood parasites and their hosts, host parents are under strong selection to evolve defenses against parasitism. Egg rejection is an efficient and common defense against parasitism, although some apparently suitable hosts do not reject cuckoo ***： Sparrows Ploceidae are widespread throughout the Old World, and they have a suitable diet for rearing cuckoos, but still they are rarely exploited by brood parasites. To solve such puzzle, we conducted artificial parasitism and cross-fostering experiments in Russet Sparrow （Posset cinnomomeus）.Results： The present study showed that Russet Sparrows have no egg recognition ability, but recognize their own nestlings and eject alien chicks or starve them to death. They may use visual cues in chick recognition, although they accept sister species Tree Sparrow （Posset montonus）.Conclusions： By rejecting nestlings of foreign species, Russet Sparrows have succeeded to escape from the brood parasitism by cuckoos and other parasites. Our studies shed light on the puzzle why some species are not utilized by cuckoo parasites as hosts,

关键词： Chick recognition Coevolution Cross-fostering Egg recognition Posset cinnamomeus

Calibration and Validation of an All-Sky Imager

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Atmospheric and Oceanic Science Letters 2009年第4期2卷 220-223页

作者： huo juan LU Da-Ren Key Laboratory for Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The automatic all-sky imager developed by the Institute of Atmospheric Physics,Chinese Academy of Sciences,provides all-sky visible images in the red,green,and blue *** paper presents three major cali-bration experiments of the all-sky imager,geometric an-gular calibration,optical calibration,and radiometric calibration,and then infers an algorithm to retrieve rela-tive radiance from the all-sky *** experiments show that the related coefficient between retrieved radi-ance and measured radiance is about *** is feasible to use the algorithm to retrieve radiance from *** paper sets up a relationship between radiance and the im-age,which is useful for using the all-sky image in nu-merical-simulations that predict more meteorological pa-rameters.

关键词： all-sky visible image radiance cloud