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Test of the Louis scheme and COARE algorithm for friction velocity in different wind-sea/swell regimes

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Acta Oceanologica Sinica 2005年第4期24卷 20-28页

作者： gao zhiqiu HU Wen LIU Shaomin Chinese Academy of Meteorological Sciences Beijingl00081 China Jiangsu Province Key Laboratory of Meteorological Disaster and Environmental Variation Nanjing 210044 China Anhui Meteorological Bureau Hefei 230061 China State Key Laboratory of Remote Sensing Science School of Geography Beijing Normal University Beijing 100875 China

The Louis scheme and the COARE algorithm （version 3.0） are tested against eddy covariance and inertial dissipation methods for friction velocity estimates in different wind-sea/swell regimes. Atmospheric forcing data, tabulated by Donelan et al. （1997.J Phys Oceanog, 27：2087-2099）, were collected from a mast on the foredeck of a SWATH （small water-plane area, twin hull） ship in deep sea off the State of Virginia during the surface wave dynamics experiment. These data are representative of low to moderate wind regimes. The aerodynamic roughness length is determined by using the Charnock relationship. The intercomparison shows that the Louis scheme and the COARE algorithm underestimate the friction velocity by 6% and 3% respectively under pure wind sea conditions, 15% and 13% respectively under cross swell conditions, and 21% and 17% respectively under counter swell conditions. The analysis shows that these underestimations were caused by the method chosen to determine the aerodynamic roughness length because it significantly underestimates the aerodynamic roughness length. It is especially true under the cross swell and counter swell conditions.

关键词： Louis scheme friction velocity sea surface

Current and Future Precipitation Extremes over Mississippi and Yangtze River Basins as Simulated in CMIP5 Models

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Journal of Earth Science 2016年第1期27卷 22-36页

作者： Zaitao Pan Yuanjie Zhang Xiaodong Liu zhiqiu gao Department of Earth and Atmospheric Sciences Saint Louis University Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters College of Applied MeteorologyNanjing University of Information Science and Technology Institute of Earth Environment Chinese Academy of Sciences State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences

Both central-eastern U.S. and China are prone to increasing flooding from Mississippi River and Yangtze River basins respectively. This paper contrasts historical and projected spatialtemporal distribution of extreme precipitation in these two large river basins using 31 CMIP5（coupled model intercomparison project phase 5） models＇ historical and RCP8.5（representative concentration pathway） experiments. Results show that（1） over both river basins, the heaviest rainfall events have increased in recent decades while the lightest precipitation reduced in frequency. Over Mississippi River Basin, both the lightest precipitation（〈2.5 mm/day） and heaviest（〉50 mm/day） would decrease in frequency notably after mid-2020 s while intermediate events occur more frequently in future; whereas over the Yangtze River Basin, all categories of precipitation are projected to increase in frequency over the coming decades.（2） Although the consensus of CMIP5 models was able to reproduce well domain-time mean and even time-averaged spatial distribution of precipitation, they failed to simulate precipitation trends both in spatial distribution and time means. In a similar fashion, models captured well statistics of precipitation but they had difficulty in representing temporal variations of different precipitation intensity categories.（3） The well-documented 2nd half of the 20 th century surface summer cooling over the two river basins showed different associations with precipitation trends with higher anti-correlation between them over the U.S. region, implying different processes contributing to the cooling mechanisms of the two river basins.

关键词： climate change extreme precipitation flooding GCM simulation.

Structure of summer atmospheric boundary layer in the center of Arctic Ocean and its relation with sea ice extent change

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Science China Earth Sciences 2016年第5期59卷 1057-1065页

作者： BIAN LinGen DING MingHu LIN Xiang LU ChangGui gao zhiqiu Chinese Academy of Meteorological Sciences Beijing 100081 China Climate and Weather Disasters Collaborative Innovation Center Nanjing University of lnformation Science & Technology Nanjing 210044 China

The atmospheric vertical structure and changed characteristics of boundary layer parameters, as well as their relations with sea ice and temperature changes in the center of Arctic Ocean(80°–88°N) are presented by adopting GPS sounding data obtained by the 4th–6th Arctic expeditions of China and NCEP(National Centre for Environmental Prediction) reanalysis data. Obvious differences are observed regarding the tropopause, boundary layer height, temperature inversion, and vertical structure of wind speed and direction in the center Arctic Ocean in the summer of 2012, 2010, and 2014. These differences can be explained by the relations between temperature and changes in sea ice extent in September from 1979 to 2014. In September 2012, the Arctic sea ice extent decreased by 44% an with obvious warming process. In September 2010 and 2014, it decreased by 22.6% and 17% with an obvious cooling process, respectively. A comparison of the two processes shows that sea ice change has a significant influence on the structure of the atmospheric boundary layer. In the recent 30 years, the temperature changes of 1000 and 850 h Pa in the center of the Arctic Ocean have displayed an obvious warming trend and negative correlation with sea ice extent. These changes indicate that the continuous reduction of Arctic sea ice will continue the warming of the troposphere middle layer.

关键词： Arctic Ocean Atmospheric boundary layer Arctic sea ice extent Atmospheric warming

The research on boundary layer evolution characteristics of Typhoon Usagi based on observations by wind profilers

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Acta Oceanologica Sinica 2017年第9期36卷 39-44页

作者： LIAO Fei DENG Hua gao zhiqiu CHAN Pak-wai Guangzhou Meteorological Observatory Guangzhou 511430 China Guangzhou Institute of Tropical and Marine Meteorology China Meteorological Administration Guangzhou 510080 China Guangdong Ecological Meteorological Center Guangzhou 510080 China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Hong Kong Observatory Hong Kong 999077 China

Vertically exploring the characteristics of the typhoon boundary layer（TBL） plays an important role in recognizing typhoon structure. The boundary layer radial direction and tangential wind characteristics of Typhoon Usagi based on the observational data of three boundary layer wind profiler stations along the route of Typhoon Usagi（No. 1319） and by combining with sounding data. The results show that：（1） maximum tangential wind appears in the vicinity of the eye area of Usagi, and it basically maintains a height of around 1 800 m when Usagi keeps a strong typhoon level, with the rapidly decreasing strength of Usagi after it lands, the speed of the maximum tangential wind and its vertical range both decrease;（2） the height of the maximum tangential wind is close to that of the inflow layer top of the typhoon, and is greater than that of the boundary layer estimated on the basis of Richardson number or potential temperature gradient, while the height of mixed layer judged on the basis of the signal-to-noise ratio（SNR） or its gradient is usually low;（3） the the boundary layer height can reach higher than2 100 m before Usagi lands. When the typhoon level or above is achieved, the boundary layer height observed by various stations does not change much, basically staying at between 1 200 and 1 600 m. With the decreasing strength of Usagi after its landfall, the boundary layer height rapidly drops.

关键词： typhoon boundary layer height wind profiler sounding

Contrasting Characteristics of the Surface Energy Balance between the Urban and Rural Areas of Beijing

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Advances in Atmospheric Sciences 2015年第4期32卷 505-514页

作者： WANG Linlin gao zhiqiu MIAO Shiguang GUO Xiaofeng SUN Ting Maofeng LIU Dan LI State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology Institute of Urban Meteorology China Meteorological Administration State Key Laboratory of Hydroscience and Engineering Department of Hydraulic Engineering Tsinghua University Department of Civil and Environmental Engineering Princeton University Program of Atmospheric and Oceanic Sciences Princeton University

A direct comparison of urban and rural surface energy balances, as well as a variety of other variables including incoming shortwave/longwave radiation and aerosol optical depth, is conducted for the Beijing metropolitan area. The results indicate that, overall, the urban area receives a smaller amount of incoming shortwave radiation but a larger amount of incoming longwave radiation. However, comparisons in the aerosol optical depth and cloud fraction at the two locations suggest that neither aerosol optical depth nor cloud fraction alone can explain the difference in the incoming shortwave radiation. The urban–rural differences in the incoming longwave radiation are unlikely to be caused by the presence of more abundant greenhouse gases over the urban area, as suggested by some previous studies, given that water vapor is the most dominant greenhouse gas and precipitable water is found to be less in urban areas. The higher incoming longwave radiation observed over the urban area is mostly likely due to the higher temperatures of the ambient air. The urban area is also found to always produce higher sensible heat fluxes and lower latent heat fluxes in the growing season. Furthermore, the urban area is associated with a larger amount of available energy（the sum of sensible and latent heat fluxes） than the rural area, except in May and October when evapotranspiration in the rural area significantly exceeds that in the urban area. This study provides observational evidence of urban–rural contrasts in relevant energy-balance components that plausibly arise from urban–rural differences in atmospheric and land-surface conditions.

关键词： aerosol load cloud evapotranspiration surface energy balance urbanization

Seasonal and Interannual Variations of Carbon Exchange over a Rice–Wheat Rotation System on the North China Plain

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Advances in Atmospheric Sciences 2015年第10期32卷 1365-1380页

作者： CHEN Chen LI Dan gao zhiqiu Jianwu TANG GUO Xiaofeng WANG Linlin WAN Bingcheng State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences Graduate University of Chinese Academy of Sciences Program of Atmospheric and Oceanic Sciences Princeton University The Ecosystems Center Marine Biological Laboratory

Rice-wheat （R-W） rotation systems are ubiquitous in South and East Asia, and play an important role in modulating the carbon cycle and climate. Long-term, continuous flux measurements help in better understanding the seasonal and interannual variation of the carbon budget over R-W rotation systems. In this study, measurements of CO2 fluxes and meteorological variables over an R-W rotation system on the North China Plain from 2007 to 2010 were analyzed. To analyze the abiotic factors regulating Net Ecosystem Exchange （NEE）, NEE was partitioned into gross primary production （GPP） and ecosystem respiration. Nighttime NEE or ecosystem respiration was controlled primarily by soil temperature, while daytime NEE was mainly determined by photosythetically active radiation （PAR）. The responses of nighttime NEE to soil temperature and daytime NEE to light were closely associated with crop development and photosynthetic activity, respectively. Moreover, the interannual variation in GPP and NEE mainly depended on precipitation and PAR. Overall, NEE was negative on the annual scale and the rotation system behaved as a carbon sink of 982 g C m 2 per year over the three years. The winter wheat field took up more CO2 than the rice paddy during the longer growing season, while the daily NEE for wheat and rice were -2.35 and -3.96 g C m-2, respectively. After the grain harvest was subtracted from the NEE, the winter wheat field became a moderately strong carbon sink of 251-334 g C m-2 per season, whereas the rice paddy switched to a weak carbon sink of 107-132 per season.

关键词： net ecosystem exchange gross primary production rice-wheat rotation system

On the surface fluxes characteristics and roughness lengths at Zhongshan station,Antarctica

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International Journal of Digital Earth 2019年第8期12卷 878-892页

作者： Changwei Liu Yubin Li Qinghua Yang Linlin Wang Xianqiao Wang Shimin Li zhiqiu gao Key Laboratory of Meteorological Disaster of Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters School of Geography and Remote SensingNanjing University of Information Science and TechnologyNanjingChina Key Laboratory of Research on Marine Hazards Forecasting National Marine Environment Forecasting CenterBeijingPeople’s Republic of China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingPeople’s Republic of China

Over Antarctica,surface fluxes play an important role in the local atmospheric dynamical *** reveal the surface fluxes characteristics and aerodynamic and thermal roughness lengths over Zhongshan station,Antarctica,this paper analyzes the data observed at the station during 3 March 2008 through 15 February *** is found that easterlies dominated this site throughout the whole year,with a maximum(average)speed of 25(5.6)m s−1 at 3.9 m height,and the annual maximum(minimum)surface temperature reached 291.05(230.05)K,while the annual maximum(minimum)air-specific humidity was 4.1(0.05)g/kg at 3.9 m *** maximum(minimum)values of seasonal mean temperature,humidity,each radiation components,sensible and latent heat flux occurred in summer(winter),while for the seasonal averaged wind speed andτthe minimums(maximums)appeared in summer(autumn).After comparing with a partially linear regression method for aerodynamic roughness length and four previous equations that derive thermal roughness length from surface Reynolds number,constant values of aerodynamic roughness length as 3.6×10^(−3)m and thermal roughness length as 1.2×10^(−4)m at this site were validated by using the other three level observations and suggested for future studies.

关键词： Antarctica Zhongshan station turbulent momentum flux sensible heat flux aerodynamic roughness length thermal roughness length

CH₄ Monitoring and Background Concentration at Zhongshan Station, Antarctica

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Atmospheric and Climate Sciences 2016年第1期6卷 135-144页

作者： Lingen Bian zhiqiu gao Yulong Sun Minghu Ding Jie Tang Russell C. Schnell Chinese Academy of Meteorological Sciences Beijing China Climate and Weather Disasters Collaborative Innovation Center Nanjing University of Information Science & Technology Nanjing China NOAA ESRL Global Monitoring Division R/GMD Boulder CO USA

Background CH4 concentration and seasonal variations measured at Zhongshan Station (69°22'2''S, 76°21'49''E, 18.5 m) in Antarctica from 2008 through 2013 are presented and discussed. From 2008-2013 CH4 was measured in weekly flask samples and started on line measurement by Picarro CO2/CH4/H2O analyzer from March, 2010-2013. These CH4 measurements show the expected growth period of CH4 concentration during February (Antarctic spring) with a peak in September (fall). Irrespective of wind direction, CH4 concentrations distribute evenly after the removal of polluted air from station operations, accounting for 1% of the data. The mean daily cycle of CH4 concentration in all four seasons is small. The monthly mean CH4 concentration at Zhongshan station is similar to those at other stations in Antarctica showing that CH4 observed in Antarctica is fully mixed in the atmosphere as it is transported from the northern through the southern hemisphere. The annual CH4 increase in recent years at Zhongshan station is 4.8 ppb·yr-1.

关键词： Antarctica Zhongshan Station CH4 Background CH4 Characteristics

Surface Ozone Monitoring and Background Concentration at Zhongshan Station, Antarctica

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Atmospheric and Climate Sciences 2018年第1期8卷 1-14页

作者： Lingen Bian Lei Ye Minghu Ding zhiqiu gao Xiangdong Zheng Russell C. Schnell Chinese Academy of Meteorological Sciences Beijing China Climate and Weather Disasters Collaborative Innovation Center Nanjing University of Information Science & Technology Nanjing China NOAA ESRL Global Monitoring Division R/GMD Boulder USA

The background surface O3 concentrations and seasonal changes observed at the Zhongshan Station (69°22'2''S, 76°21'49''E;18.5 m), east Antarctica from 2008 to 2013 are presented. Irrespective of wind direction, surface O3 concentrations distribute evenly after the removal of polluted air from station operations, accounting for 1.1% of the data. These O3 exhibit the expected lowest in summer, with a peak in winter. The daily range of average O3 in all four seasons is small. The monthly mean O3 is similar to that of other stations in Antarctica, with seasonal CO2 amplitudes in the order of 15 ppb to 35 ppb. Surface O3 significantly negatively correlated with UVB in the spring and autumn, with correlation coefficients of 0.50 and 0.57 under the 0.01 significance test. Furthermore, the surface O3 concentration during polar nights was 1 - 2 times higher than that during polar days. Thus, the chemical effect of the aurora lights was the dominant cause of ozone destruction, showing that surface O3 observed in Antarctica has a small interferences from human activities in the atmosphere as it moves from the north through the southern hemisphere.

关键词： Antarctica Zhongshan Station Surface Ozone Background Concentration