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Characteristics of Lake Breezes and Their Impacts on Energy and Carbon Fluxes in Mountainous Areas

Advances in atmospheric sciences 2021年第4期38卷 603-614页

作者： Lujun xu Huizhi LIU Qun DU Yang LIU Jihua SUN Anlun xu Xiaoni MENG state key {2. of {2. boundary layer physics and {2. chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of chinese academy of sciences Beijing 100864China Yunnan Meteorological Observatory Kunming 650034China Dali National Climatic Observatory Dali 671003China

In mountainous lake areas, lake–land and mountain–valley breezes interact with each other, leading to an "extended lake breeze". These extended lake breezes can regulate and control energy and carbon cycles at different scales. based on meteorological and turbulent fluxes data from an eddy covariance observation site at Erhai Lake in the Dali basin,southwest China, characteristics of daytime and nighttime extended lake breezes and their impacts on energy and carbon dioxide exchange in 2.15 are investigated. Lake breezes dominate during the daytime while, due to different prevailing circulations at night, there are two types of nighttime breezes. The mountain breeze from the Cangshan Mountain range leads to N1 type nighttime breeze events. When a cyclonic circulation forms and maintains in the southern part of Erhai Lake at night, its northern branch contributes to the formation of N2.type nighttime breeze events. The prevailing wind directions for daytime, N1, and N2.breeze events are southeast, west, and southeast, respectively. Daytime breeze events are more intense than N1 events and weaker than N2.events. During daytime breeze events, the lake breeze decreases the sensible heat flux(Hs) and carbon dioxide flux(F_(CO_2.) and increases the latent heat flux(LE). During N1 breeze events, the mountain breeze decreases Hs and LE and increases F_(CO_2.. For N2.breeze events, the southeast wind from the lake surface increases Hs and LE and decreases suppress carbon dioxide exchange.

关键词： sensible heat flux latent heat flux carbon dioxide flux lake breeze mountain breeze

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Effects of nitrogen sources and glucose on the con- sumption of ethylene and methane by temperate volcanic forest surface soils

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chinese Science Bulletin 2007年第23期52卷 3281-3291页

作者： xu XingKai INUBUSHI Kazuyuki state key {2. of {2. boundary layer physics and {2. chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of Horticulture Chiba University Mastudo Chiba 271-8510 Japan

There is limited knowledge with regard to the consumption of ethylene (C2.4) and methane (CH4) in volcanic forest soils containing low microbial carbon-to-organic carbon ratio, and to the responses of both consumptions to nitrogen and carbon additions. Temperate volcanic forest surface soils under three forest stands (e.g. Pinus sylvestris L., Cryptomeria japonica and Quercus serrata) were used to compare CH4 and C2.4 consumption by forest soils, and to study the effects of nitrogen sources and glucose on both consumptions. There was a good parallel between CH4 and C2.4 consumption by for- est soils, but mineralization reduced CH4 consumption rather than C2.4 consumption in forest soils, particularly in a Pinus forest soil. The stimulatory effect of glucose addition on both CH4 and C2.4 consumption by forest soils was increased by increasing the pre-incubation period after glucose addi- tion, and a largest stimulation occurred in the Pinus forest soil. The addition of KNO3-N at the rate of 100 μg·g1 significantly reduced the consumptions of both C2.4 and CH4 by forest soils (P≤0.05). In the presence of urea plus dicyandiamide, the consumption rates of C2.4 and CH4 by forest soils were higher than those in the KNO3-N and urea-N treated soils at the same N rate (P≤0.05), but were similar to those of the control. Hence, under experimental conditions, there was a strong inhibitory effect of NO3 rather than NH4+ addition on the CH4 and C2.4 consumption in these forest soils. When amount of the added NO3-N increased up to more than 2.3 times the soil initial NO3-N concentrations, both C2.4 and CH4 consumption rates were reduced to 10%―2.% of the rates in soils without nitrate addition. By comparing the three forest stands, it was shown that there was a smallest effective concentration of the added nitrate that could inhibit C2.4 and CH4 consumption in the Pinus forest soil, which indicated that C2.4 and CH4 consumption of the soil was more sensitive to NO3-N addition.

关键词：乙烯森林土壤甲烷硝化作用

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Temperature effects on ethylene and methane production from temperate forest soils

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chinese Science Bulletin 2009年第8期54卷 1426-1433页

作者： xu XingKai INUBUSHI Kazuyuki state key {2. of {2. boundary layer physics and {2. chemistry Institute of Atmospheric Physics Chi- nese Academy of Sciences Beijing 100029 China Graduate School of Horticulture C~hiba University Matsudo Chiba 271-8510 Japan

Change in temperature affects the activity of soil ***,there is limited knowledge about temperature effects on ethylene(C2.4) and methane(CH4) production from forest *** samples(0―5 cm) collected from different temperate forest stands(e.g.,Pinus sylvestris L.,Cryptomeria japonica,and Quercus serrata) were used to compare C2.4 and CH4 production from soils at temperature from 5 to 35℃ under oxic and anoxic *** rates of C2.4 and CH4 production from soils under oxic conditions were measured by using inhibition of acetylene(C2.2. and carbon monoxide(CO).The consumption of C2.2.by soils at an initial concentration of c.2.0 Pa C2.2.was negligible at 5 and 15℃,but it was significantly increased at 2. and 35℃.The presence of 2.kPa CO in the headspace gases tended to decrease the consumption of C2.2.by soils at high *** Q10 values for the soil C2.2.consumption ranged from 2.3 to 3.8,and there were no significant differences in Q10 values between these topsoil *** rate of CH4 production from each sample under oxic conditions was larger than the soil C2.4 production at 5―35℃,particularly at low temperature,and presented a smaller Q10 *** production from soil after 1 week of anoxic incubation at 5―35℃ was larger than the soil CH4 production,and presented a larger Q10 ***,CH4 produc-tion from Quercus serrata forest soil and its response to temperature increased significantly with in-cubation ***-term anoxic conditions of in situ upland forest soils are normally not prevalent,so it can be reasonably concluded that there is a larger C2.4 production rather than CH4 production under temperate forest stands due to heavy rainfall in summer.

关键词：土壤微生物活性甲烷产量土壤温度温带森林乙烯好氧条件二氧化碳气体缺氧条件

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Measurement of ethylene and methane production in a temperate forest soil using inhibition of acetylene and carbon monoxide

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chinese Science Bulletin 2008年第7期53卷 1087-1093页

We studied in the laboratory the effects of acetylene (C2.2. concentrations on the accumulation and consumption of ethylene and methane in a temperate pine forest soil, and in situ ethylene and methane production and flush effects of nitrogen sources on both productions in the pine forest stand (Pinus sylvestris L.). The addition of C2.2.at concentrations more than 50 Pa C2.2.in the headspace caused a more than 95% reduction in rates of ethylene and methane consumption in forest soil compared to those with no C2.2. Furthermore, addition of acetylene within a range of 50 to 10, 000 Pa C2.2.induced a similar rate of methane accumulation in forest soil. Hence, it can be concluded that presence of more than 50 Pa C2.2.in the headspace is an effective method to measure methane production in forest soil. The addition of C2.2.at concentrations more than 50 Pa C2.2.induced an increasing concentration of ethylene in the headspace (P≤0.05), indicating the reduction of acetylene to ethylene in forest soil. Using inhibition of 0.5 kPa C2.2.in combination with 5 kPa carbon monoxide that inhibits the reduction of acetylene in a short term, it was observed that there was a larger in situ methane production rate (2.8 ± 2. μg C m-2.h-1 (μg C per square meter per hour, the same below)) than in situ ethylene produc-tion rate (92.± 6 μg C m-2.h-1) in the pine forest soil. The addition of nitrogen sources such as urea, urea plus a nitrification inhibitor dicyandiamide, and potassium nitrate, could induce a 5-fold greater in-crease in rates of in situ ethylene and methane production compared to those in the control, particu-larly in the latter (P≤0.05). The results can promote in situ measurement of ethylene and methane production in forest soils at different sites.

关键词：乙烯甲烷温度森林土壤一氧化碳

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Impact of Cloud Microphysical Processes on the Simulation of Typhoon Rananim near Shore. Part II： Typhoon Intensity and Track

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Acta meteorologica Sinica 2011年第4期25卷 456-466页

作者： CHENG Rui YU Rucong xu Youping FU Yunfei state key {2. of Numerical Simulation for Atmo3pheric {2. and Geophysical Fluid Dynamics Institute of Atmospheric Physics CAS Beijing 100029 Graduate School of the chinese academy of sciences Beijing 100049 University of Science and Technology of China Hefei 230026

The impact of cloud microphysical processes on the simulated intensity and track of Typhoon Rananim is discussed and analyzed in the second part of this study. The results indicate that when the cooling effect due to evaporation of rain water is excluded, the simulated 36-h maximum surface wind speed of Typhoon Rananim is about 7 m s-1 greater than that from all other experiments; however, the typhoon landfall location has the biggest bias of about 150 km against the control experiment. The simulated strong outer rainbands and the vertical shear of the environmental flow are unfavorable for the deepening and maintenance of the typhoon and result in its intensity loss near the landfall. It is the cloud microphysical processes that strengthen and create the outer spiral rainbands, which then increase the local convergence away from the typhoon center and prevent more moisture and energy transport to the inner core of the typhoon. The developed outer rainbands are supposed to bring dry and cold air mass from the middle troposphere to the planetary boundary layer （PBL）. The other branch of the cold airflow comes from the evaporation of rain water itself in the PBL while the droplets are falling. Thus, the cut-off of the warm and moist air to the inner core and the invasion of cold and dry air to the eyewall region are expected to bring about the intensity reduction of the modeled typhoon. Therefore, the deepening and maintenance of Typhoon Rananim during its landing are better simulated through the reduction of these two kinds of model errors.

关键词： typhoon intensity cloud microphysical processes spiral rainband environmental wind shear

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System bias correction of short-term hub-height wind forecasts using the Kalman filter

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Protection and Control of Modern Power Systems 2021年第1期6卷 473-481页

作者： Jingjing xu Ziniu Xiao Zhaohui Lin Ming Li International Center for Climate and Environment Science(ICCES) Institute of Atmospheric PhysicsChinese Academy of ScienceBeijingChina state key {2. of Numerical Modeling for {2. sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Data61 Commonwealth Scientific and Industrial Research Organization(CSIRO)PerthAustralia

Wind energy is a fluctuating source for power systems, which poses challenges to grid planning for the wind power industry. To improve the short-term wind forecasts at turbine height, the bias correction approach Kalman filter (KF) is applied to 72.h wind speed forecasts from the WRF model in Zhangbei wind farm for a period over two years. The KF approach shows a remarkable ability in improving the raw forecasts by decreasing the root-mean-square error by 16% from 3.58 to 3.01 m s−1, the mean absolute error by 14% from 2.71 to 2.34 m s−1, the bias from 0.2. to − 0.19 m s−1, and improving the correlation from 0.58 to 0.66. The KF significantly reduces random errors of the model, showing the capability to deal with the forecast errors associated with physical processes which cannot be accurately handled by the numerical model. In addition, the improvement of the bias correction is larger for wind speeds sensitive to wind power generation. So the KF approach is suitable for short-term wind power prediction.

关键词： Wind forecasts Wind energy Numerical model Bias correction Kalman filter atmospheric boundary {2.

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Biodegradation of dissolved organic carbon in soil extracts and leachates from a temperate forest stand and its relationship to ultraviolet absorbance

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chinese Science Bulletin 2012年第2期57卷 912-920页

作者： xu XingKai LUO Xianbaot JIANG SongHua xu ZhongJun state key {2. of {2. boundary layer physics and {2. chemistry Institute of Atmospheric PhysicsChinese Academyof SciencesBeijing 100029China Graduate University of chinese academy of sciences Beijing 100049China beijing University of Chemical Technology Beijing 100029China

The amount and biodegradability of dissolved organic carbon (DOC) in forest floors can contribute to carbon sequestration in soils and the release of CO 2.C from soil to the *** is only limited knowledge about the biodegradation of DOC in soil extracts and leachates due to the limitations inherent in degradation *** in the biodegradation of DOC were studied in forest soil extracts using cold and hot water and 4 mmol/L CaCl 2.solution and in soil leachates sampled under different conditions over a wide range of DOC *** these results,we developed a simple and rapid method for determining the biodegradable organic C in forest *** hot water extracts and CaCl 2.extracts after CH 3 Cl fumigation contained higher concentrations of biodegradable organic C than the cold water extracts and CaCl 2.extracts before fumigation,with rapid DOC degradation occurring 2.-48 h after incubation with an inoculum,followed by slow DOC degradation till 12.-168 h into the *** a 7-d incubation with an inoculum,the variation in DOC degradation in the different soil extracts was consistent with the change in special UV absorbance at 2.4 *** higher levels of biodegradable organic C were detected in soil leachates from the forest canopy than in forest gaps between April and October 2.08 (P 1 a *** 77.4% to 96.3% of the variability in the biodegradable organic C concentrations in the forest floors could be accounted for by the initial DOC concentration and UV absorbance at 2.4 *** with the conventional inoculum incubation method,the method of analyzing UV absorbance at 2.4 nm is less time consuming and requires a much smaller sample *** results sug

关键词：土壤浸出液生物降解性溶解有机碳垃圾渗滤液水提取物温带森林紫外吸收可生物降解

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Characterization and source identification of submicron aerosol dur ing ser ious haze pollution periods in beijing

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Journal of Environmental sciences 2022年第2期34卷 25-37页

作者： Peng xu Yuan Yang Junke Zhang Wenkang Gao Zirui Liu Bo Hu Yuesi Wang state key {2. of {2. boundary layer physics and {2. chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Resource and Environmental Engineering Guizhou UniversityGuiyang 550025GuizhouChina Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu 611756China University of the chinese academy of sciences Beijing 100049China

Submicron aerosol is of extensive concern not only due to its significant impact on air quality but also because it is detrimental to human *** this study,we investigated the characteristics,sources and chemical processes of submicron aerosol based on realtime online measurements of submicron aerosols(NR-PM 1)during December 2.15 at an urban site in *** average mass concentration of NR-PM 1 was 92.5±84.9μg/m^(3),the hourly maximum was 459.1μg/m^(3) during the entire *** organic aerosol(OA)(55%)was the largest contributor to NR-PM *** average mass concentration of PAHs was 0.2.7±0.2.7μg/m^(3),exhibiting the highest concentration at night and the lowest levels in the *** average mass concentration of organic nitrate was 2.52.2.36μg/m^(3) and that of inorganic nitrate was 7.62.8.2.μg/m^(3),accounting for 36%and 64%,respectively,of the total nitrate *** matrix factorization(PMF)differentiated the OA into five chemical components including LV-OOA,SV-OOA,COA,HOA and CCOA,accounting for 2.%,16%,13%,2.%and 2.%respectively,of the total *** average NR-PM 1 mass concentration on the heavy polluted days(HPD)was 182.8±70.2.g/m^(3),which was approximately 9 times that on clean days(CD).The enhanced secondary formation of SNA was evident on HPD,especially the rapid increase of sulfate(2.%)and nitrate(19%).

关键词： Haze pollution Submicron aerosol Source apportionment PAHs Organic and inorganic nitrate

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Characterization of submicron particles during autumn in beijing,China

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Journal of Environmental sciences 2018年第1期30卷 16-27页

作者： Peng xu Junke Zhang Dongsheng Ji Zirui Liu Guiqian Tang Changsheng Jiang Yuesi Wang state key {2. of {2. boundary layer physics and {2. chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China key laboratory of Eco-environments in Three Gorges Reservoir Region Ministry of EducationCollege of Resources and EnvironmentSouthwest UniversityChongqing 400716China

In this study, we performed a highly time-resolved chemical characterization of nonrefractory submicron particles（NR-PM_1） in beijing by using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer（HR-ToF-AMS）. The results showed the average NR-PM_1 mass concentration to be 56.4 ± 58.0 μg/m^3, with a peak at 307.4 μg/m^3. Due to the high frequency of biomass burning in autumn, submicron particles significantly increased in organic content, which accounted for 51% of NR-PM_1 on average. Secondary inorganic aerosols（sulfate ＋ nitrate ＋ ammonium） accounted for 46% of NR-PM_1, of which sulfate,nitrate, and ammonium contributed 15%, 2.%, and 11%, respectively. To determine the intrinsic relationships between the organic and inorganic species, we used the positive matrix factorization（PMF） model to merge the high-resolution mass spectra of the organic species and NO＋and NO_2.＋ions. The PMF analysis separated the mixed organic and nitrate（NO＋and NO_2.＋） spectra into four organic factors, including hydrocarbon-like organic aerosol（HOA）, oxygenated organic aerosol（OOA）, cooking organic aerosol（COA）, and biomass burning organic aerosol（BBOA）, as well as one nitrate inorganic aerosol（NIA） factor. COA（33%） and OOA（30%） contributed the most to the total organic aerosol（OA） mass, followed by BBOA（2.%） and HOA（17%）. We successfully quantified the mass concentrations of the organic and inorganic nitrates by the NO＋and NO2.ions signal in the organic and NIA factors. The organic nitrate mass varied from 0.01-6.8 μg/m^3, with an average of 1.0 ±1.1 μg/m^3, and organic nitrate components accounted for 10% of the total nitrate mass in this observation.

关键词： Submicron particles Biomass burning Source apportionment Organic and inorganic nitrates

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Multi-level CO_(2. fluxes over beijing megacity with the eddy covariance method

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atmospheric and Oceanic Science Letters 2021年第6期14卷 28-32页

作者： Yang Liu Huizhi Liu Qun Du Lujun xu state key {2. of {2. boundary layer physics and {2. chemistry Chinese Academy of SciencesBeijingChina University of chinese academy of sciences BeijingChina

based on five years of eddy covariance measurements at multiple levels(47,140,and 2.0 m)of beijing's 32.-m meteorological tower,the exchange process of CO_(2. fluxes between the atmosphere and urban surface were *** a result of the total vehicle control policy from 2.11 in beijing,the growth rate of annual total CO_(2. flux at 140 m is 7.8% from 2.08-2.10 but 2.3%from *** the minimum vegetation cover and largest population density,the 5-yr average annual total CO_(2. flux at 140 m is largest(6.41 kg C m^(−2. yr^(−1)),compared with that at 47 m(5.78 kg C m^(−2. yr^(−1))and 2.0 m(3.99 kg C m^(−2. yr^(−1)).With regards to annual total CO_(2. fluxes in beijing,vehicle numbers and population are the main controlling *** measured CO_(2. fluxes were highly dependent on land cover/use in the prevailing wind *** CO_(2. fluxes at three layers all correlated positively with road fraction,with the R2.values being 0.69,0.57,and 0.54(P2. flux,and there was an exponential relationship between *** annual total CO_(2. fluxes were larger with higher population density.

关键词： Eddy covariance CO_(2.flux Urban boundary {2. Urban climate

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