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How did high temperature extremes in southern Xinjiang,China induce the repaid rise in jujube futures prices in the summer of 2021?

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Advances in climate change Research 2023年第3期14卷 449-457页

作者： De-Qian LI Shu-Juan HU Jing-Jing ZHANG Chen-Bin GAO Bing-Qian ZHOU Wen-Xin ZHANG Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China

In the summer of 2021,southern Xinjiang,China,experienced a temporary period of high temperature extremes.Because of this weather event,jujube futures prices rose by more than 50%in a short time.To clarify the influence mechanism of these two events,we investigated the current status of jujube farming and collected investors’online comments.We analysed these comments specifically using textual analysis tools,such as co-word networks.Results showed that the concerns of investors about the reduction in jujube production triggered by high temperature extremes were the primary reason for the rapid rise in jujube futures prices.Especially in combination with the cultivation density of jujube and their adaptability to the growing environment,a new understanding can be obtained.That is to say,when a crop is excessively densely cultivated in a region and is highly sensitive to a meteorological variable anomaly at a certain growth stage,a less destructive local extreme weather event could induce severe panic among investors regarding production reduction and thus influence the normal changes in futures price.In response to the impact mechanisms revealed in this study,we proposed policy recommendations,such as strengthening the degree of crop damage disclosure and designing weather futures derivatives,to address similar situations in the future.This study not only fills the gap in the research on the impact paths of high temperature extremes on jujube futures prices but also has a reference value for securing the stability of futures prices of related agricultural products in the future.

关键词： Jujube futures prices High temperature extremes Co-word networks Market hot topics Southern Xinjiang

Attribution of the Tibetan Plateau to northern drought

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National Science Review 2020年第3期7卷 489-492页

作者： Yuzhi Liu Yaohui Li Jianping Huang Qingzhe Zhu Shanshan Wang Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou University Institute of arid Meteorology China Meteorology Administration

The Tibetan Plateau (TP), which is located in Asia and has an average elevation of over 4000 m, acts as a raised source of heat [1] and an isolated region of humidity in the atmosphere [2]. The TP serves as a ‘world ... 详细信息

关键词： Attribution of the Tibetan Plateau to northern drought

Spatial–temporal characteristics of haze and vertical distribution of aerosols over the Yangtze River Delta of China

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Journal of Environmental Sciences 2018年第4期30卷 12-19页

作者： Yueqian Cao Wu Zhang Wenjing Wang Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric Sciences Lanzhou University

Variation of haze events occurred in the Yangtze River Delta（YRD） of China, the characteristics of meteorological elements and the vertical distribution of aerosols during haze episodes were analyzed by utilizing data of ground observation, radiosonde and CALIPSO. The results illustrate that the frequency of haze events between 1981 and 2010 peaked in winter but bottomed out in summer and decreased from north to south in the YRD region, reaching at the lowest point in ＂low frequency center＂ - Shanghai. When haze happened, the most seriously affected area was 2-4 km above the ground and the concentrated range of total backscattering coefficient（TBC） that decreased with altitude was 0.8 × 10^（-3）-2.5 × 10^（-3） km^（-1）·sr^（-1）. Particulate depolarization ratio（PDR） was less than 40%in a large part and 93% aerosols over the YRD area were regular particles, while the irregular ones concentrated on 2 km above the surface and the irregularity rose up but the diversity diminished when altitude increased. Color ratio（CR） was lower than 1.2 mostly at all altitudes and distributed asymmetrically above the ground. Nearly 80% aerosols under10 km were fine particles（CR 〈1.0） clustered at 2-4 km. Large particles（CR 〉 1.2） aggregated in lower troposphere massively yet relatively smaller ones gathered in middle and upper troposphere. In the YRD region, aerosols with more powerful capabilities were wider and less regular than the ones of Northwestern China.

关键词： Yangtze River Delta Haze Aerosol Spatial-temporal characteristics Vertical distribution

Aerosol optical properties and its direct radiative forcing over Tibetan Plateau from 2006 to 2017

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Particuology 2023年第3期74卷 64-73页

作者： Hongru Bi Siyu Chen Dan Zhao Fuquan Lu Yu Chen Yawen Guan Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou UniversityLanzhou730000China key laboratory of Land Surface Process and climate change in Cold and arid Regions Northwest Institute of Eco-Environment and ResourcesLanzhou730000China

Studies on optical properties of aerosols can reduce the uncertainty for modelling direct radiative forcing(DRF)and improve the accuracy for discussing aerosols effects on the Tibetan Plateau(TP)climate.This study investigated the spatiotemporal variation of aerosol optical and microphysical properties over TP based on OMI and MERRA2,and assessed the influence of aerosol optical properties on DRF at NamCo station(30°46.44′N,90°59.31′E,4730 m)in the central TP from 2006 to 2017 based on a long measurement of AERONET and the modelling of SBDART model.The results show that aerosol optical depth(AOD)exhibits obvious seasonal variation over TP,with higher AOD500nm(>0.75)during spring and summer,and lower value(<0.25)in autumn and winter.The aerosol concentrations show a fluctuated rising from 1980 to 2000,significant increasing from 2000 to 2010 and slight declining trend after 2013.Based on sensitivity experiments,it is found that AOD and single scattering albedo(SSA)have more important impact on the DRF compared withαvalues and ASY.When AOD440nm increases by 60%,DRF at the TOA and ATM is increased by 57.2%and 60.2%,respectively.When SSA440nm increases by 20%,DRF at the TOA and ATM decreases by 121%and 96.7%,respectively.

关键词： Direct radiative forcing Aerosol optical depth Single scattering albedo Santa Barbara DISORT Atmospheric Radiative Transfer Model Tibetan plateau

An overview of the influence of atmospheric circulation on the climate in arid and semi-arid region of Central and East Asia

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Science China Earth Sciences 2018年第9期61卷 1183-1194页

作者： Yuzhi LIU Chuqiao WU Rui JIA Jianping HUANG Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric Sciences Lanzhou University

The arid and semi-arid(ASA) region of Asia occupies a large area in the middle latitudes of the Northern Hemisphere, of which the main body is the ASA region of Central and East Asia(CEA). In this region, the climate is fragile and the environment is sensitive. The eastern part of the ASA region of CEA is located in the marginal zone of the East Asian monsoon and is jointly influenced by westerly circulation and the monsoon system, while in the western part of the ASA of CEA,the climate is mainly controlled by westerly circulation. To understand and predict the climate over this region, it is necessary to investigate the influence of general circulation on the climate system over the ASA region of CEA. In this paper, recent progress in understanding the relationship between the general circulation and climate change over the ASA region is systematically reviewed. Previous studies have demonstrated that atmospheric circulation represents a significant factor in climate change over the ASA region of CEA. In the years with a strong East Asian summer monsoon, the water vapor flux increases and precipitation is abundant in the southeastern part of Northwest China. The opposite situation occurs in years when the East Asian summer monsoon is weak. With the weakening of the East Asian summer monsoon, the climate tends to dry over the semi-arid region located in the monsoon marginal zone. Recently, owing to the strengthening of the South Asian monsoon, more water vapor has been transported to the ASA region of Asia. The Plateau summer monsoon intensity and the precipitation in summer exhibit a significant positive correlation in Central Asia but a negative correlation in North China and Mongolia. A significant positive correlation also exists between the westerly index and the temperature over the arid region of CEA. The change in the westerly circulation may be the main factor affecting precipitation over the arid region of Central Asia.

关键词：气候系统半干旱循环东亚中央大气亚洲季风季风系统

Atmospheric Warming Slowdown during 1998-2013 Associated with Increasing Ocean Heat Content

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Advances in Atmospheric Sciences 2019年第11期36卷 1188-1202,I0006,I0007,I0008,I0009,I0010,I0011页

作者： Changyu LI Jianping HUANG Yongli HE Dongdong LI Lei DING Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou University

Although atmospheric greenhouse gas concentrations continuously increased, there was relatively little change in global-averaged surface temperatures from 1998 to 2013, which is known as atmospheric warming slowdown. For further understanding the mechanism involved, we explored the energy redistribution between the atmosphere and ocean in different latitudes and depths by using data analysis as well as simulations of a coupled atmosphere–ocean box model. The results revealed that, compared with observational changes of ocean heat content (OHC) associated with rapid warming, the OHC changes related to warming slowdown are relatively larger in multiple ocean basins, particularly in the deeper layer of the Atlantic. The coupled box model also showed that there is a larger increasing trend of OHC under the warming slowdown scenario than the rapid warming scenario. Particularly, during the warming slowdown period, the heat storage in the deeper ocean increases faster than the ocean heat uptake in the surface ocean. The simulations indicated that the warming patterns under the two scenarios are accompanied by distinct outgoing longwave radiation and atmospheric meridional heat transport, as well as other related processes, thus leading to different characteristics of ocean heat uptake. Due to the global energy balance, we suggest this slowdown has a tight relationship with the accelerated heat transport into the global ocean.

关键词： warming slowdown ocean heat content box model heat transport

Estimation of the Aerosol Radiative Effect over the Tibetan Plateau Based on the Latest CALIPSO Product

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Journal of Meteorological Research 2018年第5期32卷 707-722页

作者： Rui JIA Yuzhi LIU Shan HUA Qingzhe ZHU Tianbin SHAO Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou University

Based on the CALIPSO （Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation） Version 4.10 products released on 8 November 2016, the Level 2 （L2） aerosol product over the Tibetan Plateau （TP） is evaluated and the aerosol radiative effect is also estimated in this study. As there are still some missing aerosol data points in the day-time CALIPSO Version 4.10 L2 product, this study re-calculated the aerosol extinction coefficient to explore the aer-osol radiative effect over the TP based on the CALIPSO Level 1 （L1） and CloudSat 2B-CLDCLASS-LIDAR products. The energy budget estimation obtained by using the AODs （aerosol optical depths） from calculated aerosol extinction coefficient as an input to a radiative transfer model shows better agreement with the Earth＇s Radiant En- ergy System （CERES） and CloudSat 2B-FLXHR-LIDAR observations than that with the input of AODs from aero- sol extinction coefficient from CALIPSO Version 4.10 L2 product. The radiative effect and heating rate of aerosols over the TP are further simulated by using the calculated aerosol extinction coefficient. The dust aerosols may heat the atmosphere by retaining the energy in the layer. The instantaneous heating rate can be as high as 5.5 K day^-1 de-pending on the density of the dust layers. Overall, the dust aerosols significantly affect the radiative energy budget and thermodynamic structure of the air over the TP, mainly by altering the shortwave radiation budget. The signific-ant influence of dust aerosols over the TP on the radiation budget may have important implications for investigating the atmospheric circulation and future regional and global climate.

关键词： aerosol radiative effect Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation （CALIPSO） Version 4.10 product Tibetan Plateau

Multiple Equilibria in a Land–Atmosphere Coupled System

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Journal of Meteorological Research 2018年第6期32卷 950-973页

作者： Dongdong LI Yongli HE Jianping HUANG Lu BI Lei DING Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric Sciences Lanzhou University

Many low-order modeling studies indicate that there may be multiple equilibria in the atmosphere induced by thermal and topographic forcings.However,most work uses uncoupled atmospheric model and just focuses on the multiple equilibria with distinct wave amplitude,i.e.,the high-and low-index equilibria.Here,a low-order coupled land–atmosphere model is used to study the multiple equilibria with both distinct wave phase and wave amplitude.The model combines a two-layer quasi-geostrophic channel model and an energy balance model.Highly truncated spectral expansions are used and the results show that there may be two stable equilibria with distinct wave phase relative to the topography:one(the other)has a lower layer streamfunction that is nearly in(out of)phase with the topography,i.e.,the lower layer ridges(troughs)are over the mountains,called ridge-type(trough-type)equilibria.The wave phase of equilibrium state depends on the direction of lower layer zonal wind and horizontal scale of the topography.The multiple wave phase equilibria associated with ridge-and trough-types originate from the orographic instability of the Hadley circulation,which is a pitch-fork bifurcation.Compared with the uncoupled model,the land–atmosphere coupled system produces more stable atmospheric flow and more ridge-type equilibrium states,particularly,these effects are primarily attributed to the longwave radiation fluxes.The upper layer streamfunctions of both ridge-and trough-type equilibria are also characterized by either a high-or low-index flow pattern.However,the multiple wave phase equilibria associated with ridge-and trough-types are more prominent than multiple wave amplitude equilibria associated with high-and low-index types in this study.

关键词： multiple equilibria land–atmosphere coupling wave phase longwave radiation stability

Theory of three-pattern decomposition of global atmospheric circulation

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Science China Earth Sciences 2020年第9期63卷 1248-1267页

作者： Shujuan HU Bingqian ZHOU Chenbin GAO Zhihang XU Qingwan WANG Jifan CHOU Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China

This paper reviews the three-pattern decomposition of global atmospheric circulation(3P-DGAC)developed in recent years,including the decomposition model and the dynamical equations of global horizontal,meridional,and zonal circulations.Compared with the traditional two-dimensional(2D)circulation decomposition method,the 3P-DGAC can effectively decompose the actual vertical vorticity into two components that are caused by the horizontal circulation and convergent/divergent movement(associated with the meridional and zonal circulations).It also decomposes the vertical velocity into the components of the meridional vertical circulation and the zonal vertical circulation,thus providing a new method to study the dynamical influences of convergent/divergent motions on the evolution of actual vertical vorticity and an accurate description of local vertical circulations.The 3P-DGAC is a three-dimensional(3D)circulation decomposition method based on the main characteristics of the actual atmospheric movements.The horizontal,meridional,and zonal circulations after the 3P-DGAC are the global generalization of Rossby waves in the middle-high latitudes and Hadley and Walker circulations in low latitudes.Therefore,the three-pattern decomposition model and its dynamical equations provide novel theoretical tools for studying complex interactions between middle-high and low latitude circulations as well as the physical mechanisms of the abnormal evolution of large-scale atmospheric circulations under the background of global warming.

关键词： Horizontal circulation Meridional circulation Zonal circulation Three-pattern decomposition of global atmospheric circulation(3P-DGAC) Dynamical equations