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Comparison of Nonlinear Local Lyapunov Vectors with Bred Vectors, Random Perturbations and Ensemble Transform Kalman Filter Strategies in a Barotropic Model

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Advances in Atmospheric sciences 2016年第9期33卷 1036-1046页

作者： Jie FENG Ruiqiang ding Jianping LI Deqiang liu State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 College of Earth Science University of Chinese Academy of SciencesBeijing 100049 Global Systems Division Earth System Research Laboratory/Oceanic and Atmospheric Research/National Oceanic and Atmospheric AdministrationBoulderCO80305USA Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information TechnologyChengdu 610225 College of Global Change and Earth System sciences Beijing Normal UniversityBeijing 100875 Joint Center for Global Change Studies Beijing 100875 Fujian meteorological Observatory Fuzhou 350001

The breeding method has been widely used to generate ensemble perturbations in ensemble forecasting due to its simple concept and low computational cost. This method produces the fastest growing perturbation modes to catch the growing components in analysis errors. However, the bred vectors （BVs） are evolved on the same dynamical flow, which may increase the dependence of perturbations. In contrast, the nonlinear local Lyapunov vector （NLLV） scheme generates flow-dependent perturbations as in the breeding method, but regularly conducts the Gram-Schmidt reorthonormalization processes on the perturbations. The resulting NLLVs span the fast-growing perturbation subspace efficiently, and thus may grasp more com- ponents in analysis errors than the BVs. In this paper, the NLLVs are employed to generate initial ensemble perturbations in a barotropic quasi-geostrophic model. The performances of the ensemble forecasts of the NLLV method are systematically compared to those of the random pertur- bation （RP） technique, and the BV method, as well as its improved version--the ensemble transform Kalman filter （ETKF） method. The results demonstrate that the RP technique has the worst performance in ensemble forecasts, which indicates the importance of a flow-dependent initialization scheme. The ensemble perturbation subspaces of the NLLV and ETKF methods are preliminarily shown to catch similar components of analysis errors, which exceed that of the BVs. However, the NLLV scheme demonstrates slightly higher ensemble forecast skill than the ETKF scheme. In addition, the NLLV scheme involves a significantly simpler algorithm and less computation time than the ETKF method, and both demonstrate better ensemble forecast skill than the BV scheme.

关键词： ensemble forecasting bred vector nonlinear local Lyapunov vector ensemble transform Kalman filter

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Identification of winter long-lasting regional extreme low-temperature events in Eurasia and their variation during 1948—2017

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Advances in Climate Change Research 2021年第3期12卷 353-362页

作者： ZHANG Ying-Xian liu Yan-Ju ding Yi-Hui Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijing100081China

Compared with short-duration events,long-lasting regional extreme low-temperature events(RELTEs)often have more severe impacts on human societies due to the induced persistence and large geographic area of related weather and climate ***,an improved objective technique was applied to identify all long-lasting RELTEs in Eurasia from the winter of 1948/1949 to 2017/2018,followed by an in-depth discussion of its variation in terms of the annual frequency,duration,impacted area,mean intensity,maximum intensity,and a comprehensive *** RELTE lasting for 52 d in the winter of 2007/2008 exhibited the longest duration,largest impacted area,and a greatest comprehensive index,which induced extremely low temperatures for more than 20 d in Western Asia,Central Asia,and *** the past 70 winters,the frequency of long-lasting RELTEs decreased,especially after the late ***,the mean and maximum intensities and comprehensive index exhibited distinctly increasing *** indicators of winter long-lasting RELTEs had a similar inter-decadal fluctuation featured by two noticeable peaks occurring around 1970 and 2007,and a remarkable recovery was discovered in the period of late 1990s to mid-2010s,especially for the occurrence of super long-lasting ***,winter long-lasting RELTEs in Eurasia showed distinct trends under various decadal climate backgrounds,i.e.,a strong negative or weak positive trend in the accelerated warming period and conversely,a strong positive or weak negative trend in the wanning slowdown *** findings indicate that we should be alert of the similar future recovery of winter long-lasting RELTEs in Eurasia,which are likely to occur in the slowdown period of global warming.

关键词： Regional extreme low-temperature events Winter Long-lasting Eurasia Climate variation

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The Relationship between Deterministic and Ensemble Mean Forecast Errors Revealed by Global and Local Attractor Radii

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Advances in Atmospheric sciences 2019年第3期36卷 271-278,339页

作者： Jie FENG Jianping LI Jing ZHANG Deqiang liu Ruiqiang ding School of Meteorology University of Oklahoma College of Global Change and Earth System Science (GCESS) Beijing Normal University Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology Cooperative Institute for Research in the Atmosphere GSD/ESRL/OAR/NOAA Fujian meteorological Observatory Wuyishan National Park meteorological Observatory State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology

It has been demonstrated that ensemble mean forecasts, in the context of the sample mean, have higher forecasting skill than deterministic(or single) forecasts. However, few studies have focused on quantifying the relationship between their forecast errors, especially in individual prediction cases. Clarification of the characteristics of deterministic and ensemble mean forecasts from the perspective of attractors of dynamical systems has also rarely been involved. In this paper, two attractor statistics—namely, the global and local attractor radii(GAR and LAR, respectively)—are applied to reveal the relationship between deterministic and ensemble mean forecast errors. The practical forecast experiments are implemented in a perfect model scenario with the Lorenz96 model as the numerical results for verification. The sample mean errors of deterministic and ensemble mean forecasts can be expressed by GAR and LAR, respectively, and their ratio is found to approach2^(1/2) with lead time. Meanwhile, the LAR can provide the expected ratio of the ensemble mean and deterministic forecast errors in individual cases.

关键词： attractor radius ensemble forecasting ensemble mean forecast error saturation

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Aerosol properties over an urban site in central East china derived from ground sun-photometer measurements

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Science china Earth sciences 2017年第2期60卷 297-314页

作者： liu Qi ding WeiDong XIE Lei ZHANG JinQiang ZHU Jun XIA XiangAo liu DongYang YUAN RenMin FU YunFei School of Earth and Space sciences University of Science and Technology of ChinaHefei 230026China Anhui meteorological Observatory Hefei 230001China Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China

Sun-photometer measurements at Hefei,an urban site located in central East china,were examined to investigate the variations of aerosol loading and optical *** is found that aerosol optical thickness(AOT)keeps higher in winter/spring and gets relatively lower in summer/*** large AOT in winter is caused by anthropogenic sulfate/nitrate aerosols,while in spring dust particles elevate the background aerosol loading and the excessive fine-mode particles eventually lead to severe *** is a dramatic decline of AOT during summer,with monthly averaged AOT reaching the maximum in June and soon the minimum in ***,aerosol size decreases consistently and single scattering albedo(SSA)reaches its minimum in *** summertime large-sized particles play a key role to change the air from clean to mild-pollution situation,while the presence of massive small-sized particles makes the air being even more *** complicated summer patterns are possibly related to the three key processes that are active in the high temperature/humidity environment concentrating on sulfate/nitrate aerosols,i.e.,gas-to-particle transformation,hygroscopic growth,and wet *** of season,the increase of SSA with increasing AOT occurs across the visible and near-infrared bands,suggesting the dominant negative/cooling effect with the elevated aerosol *** SSA spectra under varying AOT monotonically decrease with *** relatively large slope arises in summer,reinforcing the dominance of sulfate/nitrate aerosols that induce severe pollution in summer season around this city.

关键词： Aerosol optical thickness Single scattering albedo Central East china Sun-photometer

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Impacts of Atmospheric Boundary Layer Vertical Structure on Haze Pollution Observed by Tethered Balloon and Lidar

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Journal of meteorological Research 2021年第1期35卷 209-223页

作者： Haijiong SUN Yu SHI Lei liu Weichen ding Zhe ZHANG Fei HU State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 University of chinese academy of sciences Beijing 100049

In this paper, the characteristics of the atmospheric boundary layer(ABL) vertical structure over the North china Plain(NCP) during a comprehensive observation experiment conducted during 15–21 December 2018 were investigated. Observational data were obtained with a large tethered balloon, Doppler wind lidar, and ground-level instruments. The maximum concentration of PM_(2.5) exceeded 200 μg m^(-3), and the ratio of PM_(2.5)/PM_(10) was approximately 0.4(its maxi-mum was approximately 0.8) during the whole observation period, indicating the explosive growth of dominant fine-mode aerosols in the winter heating season. Elevated concentrations of pollutants decreased the solar irradiance received by the ground, resulting in lower temperature at ground level. Our results illustrate three distinct types of vertical profiles: Type 1(convective state)—the concentration of PM_(2.5) decreased nearly linearly with increase of the height below approximately 600 m;Type 2(stable state)—the PM_(2.5) concentration sharply decreased from the ground to approximately 200 m;and Type 3(multilayer structure)—some pollutants were suspended aloft in the upper air layer. Diurnal evolution of the vertical profiles of PM_(2.5) and their relationship with the changes in meteorological factors were identified. From daytime to nighttime, the vertical profiles evolved from Type 1 to Type 2 or Type 3. All the 33 vertical PM_(2.5) profiles that we obtained showed a strong relationship with elements of the ABL structure, such as the distributions of winds, the inversion layer, and turbulence activities. A light-wind layer and weak turbulence activity, especially within the inversion layer, contributed greatly to the accumulation of *** PM_(2.5) concentration patterns were also greatly affected by local ground-level emission sources and regional transport processes.

关键词： haze pollution PM_(2.5) vertical structure inversion atmospheric boundary layer(ABL)

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Sensitivity of surface air temperature change to land use/cover types in china

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Science china Earth sciences 2009年第8期52卷 1207-1215页

作者： YANG XuChao ZHANG YiLi liu LinShan ZHANG Wei ding MingJun WANG ZhaoFeng Institute of Geographic sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Institute of meteorological sciences Meteorological Bureau of Zhejiang ProvinceHangzhou 310017China Shanghai Institute of Geological Survey Shanghai 200072China

Using CRU high resolution grid observational temperature and ERA40 reanalysis surface air temperature data during 1960–1999, we investigated the sensitivity of surface air temperature change to land use/cover types in china by subtracting the reanalysis from the observed surface air temperature (observation minus reanalysis, OMR). The results show that there is a stable and systemic impact of land use/cover types on surface air temperature. The surface warming of each land use/cover type reacted differently to global warming. The OMR trends of unused land (?0.17 °C/decade), mainly comprised by sandy land, Gobi and bare rock gravel land, are obviously larger than those of the other land use/cover types. The OMR over grassland, farmland and construction land shows a moderate decadal warmingabout 0.12°C/decade, 0.10°C/decade, 0.12°C/decade, respectively. Woodland areas do not show a significant warming trend (0.06°C/decade). The overall assessment indicates that the surface warming is larger for areas that are barren and anthropogenically developed. The better the vegetation cover, the smaller the OMR warming trend. Responses of surface air temperature to land use/cover types with similar physical and chemical properties and biological processes have no significant difference. The surface air temperature would not react significantly until the intensity of land cover changes reach a certain degree. Within the same land use/cover type, areas in eastern china with intensive human activities exhibit larger warming trend. The results provide observational evidence for modeling research on the impact of land use/cover change on regional climate. Thus, projecting further surface climate of china in regional scale should not only take greenhouse gas increase into account, but also consider the impact of land use/cover types and land cover change.

关键词： surface air temperature land use/cover types OMR method observations reanalysis

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Towards More Snow Days in Summer since 2001 at the Great Wall Station,Antarctic Peninsula:The Role of the Amundsen Sea Low

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Advances in Atmospheric sciences 2020年第5期37卷 494-504页

作者： Minghu ding Wei HAN Tong ZHANG Xiaoyuan YUE Jeremy FYKE Ge liu Cunde XIAO State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Fluid Dynamics and Solid Mechanics Group Los Alamos National LaboratoryLos AlamosNew Mexico 87545USA Associated Engineering Group LtdVernonBritish Columbia V1T 9P9Canada State Key Laboratory of Earth Surface and Resource Ecology Beijing Normal UniversityBeijing 100875China beijing meteorological Observation Center Beijing 100176China

The variation in the precipitation phase in polar regions represents an important indicator of climate change and *** studied the precipitation phase at the Great Wall Station and Antarctic Peninsula(AP)region,based on daily precipitation,synoptic records and ERA-Interim data during the austral summers of 1985?***,there was no trend in the total precipitation amount or days,but the phase of summer precipitation(rainfall days versus snowfall days)showed opposite trends before and after 2001 at the *** total summer rain days/snow days increased/decreased during 1985?2001 and significantly decreased at a rate of?14.13 d(10 yr)?1/increased at a rate of 14.31 d(10 yr)?1 during 2001?2014,agreeing well with corresponding variations in the surface air ***,we found that the longitudinal location of the Amundsen Sea low(ASL)should account for the change in the precipitation phase since 2001,as it has shown a westward drift after 2001[?41.1°(10 yr)?1],leading to stronger cold southerly winds,colder water vapor flux,and more snow over the AP region during *** study points out a supplementary factor for the climate variation on the AP.

关键词： precipitation phase Great Wall Station Amundsen Sea Low

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Quantifying local predictability of the Lorenz system using the nonlinear local Lyapunov exponent

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Atmospheric and Oceanic Science Letters 2017年第5期10卷 372-378页

作者： HUAI Xiao-Wei LI Jian-Ping ding Rui-Qiang FENG Jie liu De-Qiang State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric PhysicsChinese Academy of Sciences Beijing China College of Earth Science University of Chinese Academy of Sciences Beijing China College of Global Change and Earth System Science (GCESS) Beijing Normal University Beijing China Joint Center for Global Change Studies Beijing Normal University Beijing China College of Atmospheric sciences Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology Chengdu China GIobal Systems Division Earth System Research Laboratory/Oceanic and Atmospheric Research/National Oceanic and Atmospheric Administration Boulder CO USA Fujian meteorological Observatory Fuzhou China

The nonlinear local Lyapunov exponent（NLLE） can be used as a quantification of the local predictability limit of chaotic systems. In this study, the phase-spatial structure of the local predictability limit over the Lorenz-63 system is investigated. It is found that the inner and outer rims of each regime of the attractor have a high probability of a longer than average local predictability limit, while the center part is the opposite. However, the distribution of the local predictability limit is nonuniformly organized, with adjacent points sometimes showing quite distinct error *** source of local predictability is linked to the local dynamics, which is related to the region in the phase space and the duration on the current regime.

关键词： Nonlinear local Lyapunov exponent local predictability limit chaotic system Lorenz system

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Aerosol and boundary-layer interactions and impact on air quality

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National Science Review 2017年第6期4卷 810-833页

作者： Zhanqing Li Jianping Guo Aijun ding Hong Liao Jianjun liu Yele Sun Tijian Wang Huiwen Xue Hongsheng Zhang Bin Zhu State Key Laboratory of Earth Surface Processes and Resource Ecology GCESS Beijing Normal University Department of Atmospheric and Oceanic sciences University of Maryland State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences School of Atmospheric sciences Nanjing University School of Environmental Science and Engineering Nanjing University of Information Science and Technology State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences Center for Excellence in Regional Atmospheric Environment Institute Chinese Academy of Sciences Department of Atmospheric and Oceanic sciences Peking University School of Atmospheric Physics Nanjing University of Information Science and Technology

Air quality is concerned with pollutants in both the gas phase and solid or liquid phases. The latter are referred to as aerosols, which are multifaceted agents affecting air quality, weather and climate through many mechanisms. Unlike gas pollutants, aerosols interact strongly with meteorological variables with the strongest interactions taking place in the planetary boundary layer(PBL). The PBL hosting the bulk of aerosols in the lower atmosphere is affected by aerosol radiative effects. Both aerosol scattering and absorption reduce the amount of solar radiation reaching the ground and thus reduce the sensible heat fluxes that drive the diurnal evolution of the PBL. Moreover, aerosols can increase atmospheric stability by inducing a temperature inversion as a result of both scattering and absorption of solar radiation, which suppresses dispersion of pollutants and leads to further increases in aerosol concentration in the lower *** positive feedback is especially strong during severe pollution events. Knowledge of the PBL is thus crucial for understanding the interactions between air pollution and meteorology. A key question is how the diurnal evolution of the PBL interacts with aerosols, especially in vertical directions, and affects air *** review the major advances in aerosol measurements, PBL processes and their interactions with each other through complex feedback mechanisms, and highlight the priorities for future studies.

关键词： aerosol PBL radiation aerosol-PBL interaction climate change

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The Significant Role of Radiosonde-measured Cloud-base Height in the Estimation of Cloud Radiative Forcing

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Advances in Atmospheric sciences 2021年第9期38卷 1552-1565页

作者： Hui XU Jianping GUO Jian LI Lin liu Tianmeng CHEN Xiaoran GUO Yanmin LYU ding WANG Yi HAN Qi CHEN Yong ZHANG State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China College of Earth sciences University of Chinese Academy of SciencesBeijing 100049China meteorological Observation Center China Meteorological AdministrationBeijing 100081China

The satellite-based quantification of cloud radiative forcing remains poorly understood,due largely to the limitation or uncertainties in characterizing cloud-base height(CBH).Here,we use the CBH data from radiosonde measurements over china in combination with the collocated cloud-top height(CTH) and cloud properties from MODIS/Aqua to quantify the impact of CBH on shortwave cloud radiative forcing(SWCRF).The climatological mean SWCRF at the surface(SWCRFSUR),at the top of the atmosphere(SWCRFTOA),and in the atmosphere(SWCRFATM) are estimated to be-97.14,-84.35,and 12.79 W m^(-2),respectively for the summers spanning 2010 to 2018 over *** illustrate the role of the cloud base,we assume four scenarios according to vertical profile patterns of cloud optical depth(COD).Using the CTH and cloud properties from MODIS alone results in large uncertainties for the estimation of SWCRFATM,compared with those under scenarios that consider the ***,the biases of the CERES estimation of SWCRFATM tend to increase in the presence of thick clouds with low ***,the discrepancy of SWCRFATM relative to that calculated without consideration of CBH varies according to the vertical profile of *** a uniform COD vertical profile is assumed,the largest SWCRF discrepancies occur during the early morning or late *** comparison,the two-point COD vertical distribution assumption has the largest uncertainties occurring at noon when the solar irradiation *** findings justify the urgent need to consider the cloud vertical structures when calculating the SWCRF which is otherwise neglected.

关键词： cloud base height radiosonde radiative forcing china climatology

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