This paper used potential height field data published by the China National Climate Center and the US NCEP reanalysis data. A study was conducted on a strong cold wave weather process in central and eastern China from...This paper used potential height field data published by the China National Climate Center and the US NCEP reanalysis data. A study was conducted on a strong cold wave weather process in central and eastern China from October 2 to 5, 2022. The results show that this weather process is a cold air weather process of “horizontal trough to vertical” type from the east of Novaya Zemlya Island. Cold air passes through Russia and Mongolia south, controlling northern China. The precipitation process is caused by the combination of high-altitude trough, ground front, warm and humid air flow, and precipitation weather formed by the influence of warm and humid air due to the 700 hPa shear line. The northern Sichuan Basin and the middle and lower reaches of the Yellow River in China can precipitate almost 50 mm. Water vapor is transported from the South China Sea to central and eastern China by the southwest warm and humid air flow along the west side of the West Pacific Subtropical High. Water vapor is concentrated over the precipitation area through horizontal convergence and is the most important source of water vapor causing precipitation.展开更多
This study uses data provided by the National Meteorological Information Center of China, Japan Meteorological Agency (JMA) and National Oceanic Atmospheric Administration (NOAA) Physical Sciences Laboratory of the US...This study uses data provided by the National Meteorological Information Center of China, Japan Meteorological Agency (JMA) and National Oceanic Atmospheric Administration (NOAA) Physical Sciences Laboratory of the USA to analyze a cold air weather process at the beginning of January 2021. Synoptic analysis is mainly used to summarize synoptic laws or patterns based on observational data, and describe and infer weather processes. The main conclusions are as follows: The cold air travels south along the northwest path, affecting most of China. During the cold wave process, the first cold air is weak, which has a certain cooling effect on northern China. The second cold air was guided by the low vortex, the accumulation in the transverse groove of Mongolia was strengthened, and the cooling effect was significant. The southwest jet showed an increasing trend, and the water vapor transport conditions were good. However, due to the relatively gentle southern branch system, the warm and humid air flow was weak and the precipitation level was small. The purpose of this study is to better understand a large-scale cold air weather process in January 2021 in China.展开更多
Based on the conventional meteorological data and the NCEP/NCAR 1° × 1° reanalysis data and those related to mid-scale automatic station, satellite cloud picture and radar return, with the dynamic...Based on the conventional meteorological data and the NCEP/NCAR 1° × 1° reanalysis data and those related to mid-scale automatic station, satellite cloud picture and radar return, with the dynamic diagnosis analysis method, an analysis is made on the process of the convective rainstorm of quasi-stationary front triggered by the weak cold air on June 4-7, 2014, showing: 1) the process occurred in the event of convection of a stationary front triggered by the eastward moving south trough and the southward moving weak cold air from west under the background of circulation of two ridges and one trough at the Asian-European mid-high latitude and weakening and southeastward moving subtropical high;2) a system configuration that contributes to convective rainstorms formed in the event of the convergence of low-level moisture, upper-level divergence and the continuous vertical ascending motion after the 200 hPa upper-level jet stream moved westwards from east and the 850 hPa southwest jet stream intensified;3) after the intrusion by weak cold air of the meso-scale katallobaric area formed by the accumulated warm moist air of Guangxi before the intrusion, the warm moist air rose to trigger convection;convection cells developed and spread nearby the boundary between anallobaric area and katallobaric area, during which total 5 MCSs developed and each formed a rainstorm center at the part where the MCSs coincide;a meso-scale katallobaric area forms and develops 2 - 5 hours earlier than convection, so that it is also a warning of heavy rains.展开更多
In 2005,significant rainfall reinforcement and severe disaster was induced by tropical cyclone(TC) Talim after it made landfall on the east of China.Observational analyses show that it has relationship with cold air i...In 2005,significant rainfall reinforcement and severe disaster was induced by tropical cyclone(TC) Talim after it made landfall on the east of China.Observational analyses show that it has relationship with cold air intrusion.For investigating the impact of cold air intensity,we make use of Weather Research and Forecasting(WRF) model,the synthesizer of NCEP/NCAR reanalysis data and Japan regional spectral model data,to carry out numerical experiments.Results show that rainfall reinforcement occurs in all experiments.Different intensity of cold air can modify the rainfall distribution and intensity significantly.In the rainfall center,the increment maximum of rainfall is twice as large as that of the minimum.Moderate cold air intrusion may result in the strongest rainfall reinforcement.Different cold air intensity can lead to different motion of low-level convergence lines and fronts.There is a good relationship between the rainfall region and the eastern part of the front.On one hand,strong cold air weakens the TC intensity by its intrusion into the TC center and results in weak convergence and a convergent zone and a rain band shifted southward.On the other hand,weak cold air reduces the convergence and moves the convergent zone and rain band northward.Moderate cold air intrusion maintains strong low-level convergence and high-level divergence,keeping strong upward motion over certain regions.Consequently,the rain band begins to stagnate and rainfall reinforces abruptly therein.展开更多
In southern China, cold air is a common weather process during the winter season; it can cause strong wind, sharp temperature decreases, and even the snow or freezing rain events. However, the features of the atmosphe...In southern China, cold air is a common weather process during the winter season; it can cause strong wind, sharp temperature decreases, and even the snow or freezing rain events. However, the features of the atmospheric boundary layer during cold air passage are not clearly understood due to the lack of comprehensive observation data, especially regarding turbulence. In this study, four-layer gradient meteorological observation data and one-layer, 10-Hz ultrasonic anemometer-thermometer monitoring data from the northern side of Poyang Lake were employed to study the main features of the surface boundary layer during a strong cold-air passage over southern China. The results show that, with the passage of a cold air front, the wind speed exhibits low-frequency variations and that the wind systematically descends. During the strong wind period, the wind speed increases with height in the surface layer. Regular gust packets are superimposed on the basic strong wind flow. Before the passage of cold air, the wind gusts exhibit a coherent structure. The wind and turbulent momentum fluxes are small, although the gusty wind momentum flux is slightly larger than the turbulent momentum flux. However, during the invasion of cold air, both the gusty wind and turbulent momentum fluxes increase rapidly with wind speed, and the turbulent momentum flux is larger than the gusty wind momentum flux during the strong wind period. After the cold air invasion, this structure almost disappears.展开更多
In order to improve the cold start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about th...In order to improve the cold start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about the partial working processes of the diesel engine, the amount of heat energy, enough to make the fuel self ignite at the end of compression process at different temperatures of coolant and intake air, was calculated. Several HY20 preheating plugs were used to heat up the intake air. Meanwhile, an electronic control system based on 8 bit micro controller unit (MCS 8031) was designed to automatically control the process of heating intake air. According to the various temperatures of coolant and ambient air, one plug or two plugs can automatically be selected to heat intake air. The demo experiment validated that the total system could operate successfully and achieve the scheduled function.展开更多
With the increase of mining depth, more and deeper coal mines are limited by heat disaster. The cooling energy in deep mine cooling system comes from mine water inrush or ground cooling tower, but we cannot adopt the ...With the increase of mining depth, more and deeper coal mines are limited by heat disaster. The cooling energy in deep mine cooling system comes from mine water inrush or ground cooling tower, but we cannot adopt the two methods because mine water inrush in many old coal mines in China is limited. What is more, the cooling pipelines cannot be put in narrow pit-shaft. To settle the problem above, according to the characteristics of Zhangxiaolou Coal Mine, this paper adopts the deep mine return air as the cooling energy for deep mine cooling system. In addition, we carried out cite test to extract cold energy from return air. Through monitoring the water quantity, water temperature of cooling system and air temperature, we got the thermodynamic equilibrium parameters during the cooling energy acquisition analysis and the effect of cooling system that the temperature and humidity on working face are respectively reduced to 8-12 ℃ and 8-15% through cooling. This research offers experimental reference for deep mine cooling which lacks cooling energy.展开更多
Based on intensive automatic weather station data, satellite cloud imagery, NCEP reanalyzed data, and the simulation results from mesoscale numerical models, this study analyzes the characteristics and formation mecha...Based on intensive automatic weather station data, satellite cloud imagery, NCEP reanalyzed data, and the simulation results from mesoscale numerical models, this study analyzes the characteristics and formation mechanisms of the mesoscale convection system(MCS) during the extreme precipitation event that was triggered by a weakened low-pressure inverted trough of Typhoon Haikui on August 10/2012. The results of this study show that cold air at the rear of a northeastern cold vortex creates thermodynamic conditions favorable to the development of extreme precipitation. The main body of the cold air is northward located so that the cold air invades only the middle layer of the periphery of the inverted trough. Thus, the cold air minimally affects the lower layer, which results in a vertically distributed structure of the temperature advection that augments the formation and development of convective instability stratification. In the middle troposphere, the cold air encounters the convergent, ascending, warm moist air from the low-pressure inverted trough, leading to frontogenesis. The frontogenesis enhances wind convergence which, in turn, further enhances the frontogenesis, and the positive feedback between these two forces augments the development of meso- and small-scale convection systems in the rainstorm region and its vicinity, which strengthens the upward transportation of water vapor from low layers and thickening of water vapor convergence and results in local heavy rains.展开更多
A 24-h simulation with the Advanced Regional Prediction System (ARPS) nonhydrostatic model is performed for the heavy snowfall event of 3-4 February 1998 along the eastern coast of Korean Peninsula; the results are ...A 24-h simulation with the Advanced Regional Prediction System (ARPS) nonhydrostatic model is performed for the heavy snowfall event of 3-4 February 1998 along the eastern coast of Korean Peninsula; the results are used to understand the snowfall process, including why the precipitation maxima formed along the Yeongdong coastal region rather than over the mountain slope and ridge top during. The numerical simulation with a 4-kin horizontal grid spacing and 43 levels reproduces very well the narrow snowband located off the eastern Korean coast, away from, instead of over, the Yeongdong coastal mountain range. The general evolution of the snowband agrees quite well with radar observations, while the water-equivalent precipitation amount agrees reasonably well with radar precipitation estimate. The simulation results clearly show that the snow band developed due to the lifting by a coastal front that developed because of the damming of cold air against the eastern slope of the coastal mountain range. The damming was enhanced by the advection of cold air by a tow-level mountain-parallel jet from the north, formed due to geostrophic adjustment as the on-shore upslope air was decelerated by the mountain blocking. As the onshore flow weakened later due to synoptic-scale flow pattern change, the cold front propagated off shore and the precipitation dissipated.展开更多
Air cold plasma has been used as a novel method for enhancing microbial fermentation. The aim of this work was to explore the effect of plasma on membrane permeability and the formation of ATP and NADH in Saccharomyce...Air cold plasma has been used as a novel method for enhancing microbial fermentation. The aim of this work was to explore the effect of plasma on membrane permeability and the formation of ATP and NADH in Saccharomyces cerevisiae, so as to provide valuable information for largescale application of plasma in the fermentation industry. Suspensions of S. cerevisiae cells were exposed to air cold plasma for 0, 1, 2, 3, 4 and 5 min, and then subjected to various analyses prior to fermentation (Oh) and at the 9 and 21 h stages of fermentation. Compared with nonexposed cells, cells exposed to plasma for 1 min exhibited a marked increase in cytoplasmic free Ca2+ concentration as a result of the significant increase in membrane potential prior to fermentation. At the same time, the ATP level in the cell suspension decreased by about 40%, resulting in a reduction of about 60% in NADH prior to culturing. However, the levels of ATP and NADH in the culture at the 9 and 21 h fermentation stages were different from the level at 0 h. Taken together, the results indicated that exposure of S. cerevisiae to air cold plasma could increase its cytoplasmic free Ca2+ concentration by improving the cell membrane potential, consequently leading to changes in ATP and NADH levels.展开更多
It is generally accepted that environmental factors can significantly influence respiratory system. Cold is one of these factors. Understanding of the reaction of airways to cold air is very important tool leading to ...It is generally accepted that environmental factors can significantly influence respiratory system. Cold is one of these factors. Understanding of the reaction of airways to cold air is very important tool leading to improvement in management of cold induced rhinitis, cold induced asthma, exercise induced asthma, and exacerbation of chronic airway diseases induced by cold exposure. Despite the airways are protected against cold air by powerful heat and moisture exchanging counter current system within the nose, they are still at the risk of onset and development of cold induced symptoms mainly if this mechanism is insufficient, exposed person hyperventilates or is breathing subfreezing air. Some of the mechanisms involved in cold air induced reactions are understood quite well, but some of them are still discussed as they have not been satisfactorily explained, yet. Most discussed mechanisms by which cold air may induce respiratory symptoms include direct cooling and exsiccation of mucosal surface with subsequent hyper-tonicity of superficial fluid layer and interactions between the trigeminal and the vagus nerve at the central level. Molecular background for such a reaction may rely on the presence of thermo sensitive channels, mainly TRPM8, expressed on airway afferent nerves, which initiate response to cold air, giving a rise to autonomic responses like bronchoconstriction, cough, dyspnoea, chest tightness, mucus secretion and mucosal swelling. Identification of targets for cold action in the airway may help to identify potent antagonists which may prevent or reverse cold induced reactions sharing possibility for clinical application.展开更多
<span style="font-family:Verdana;">The capacity of a cold atmospheric-pressure air plasma (CAAP) device for advanced first aid is presented. Using swine as </span><span style="font-family...<span style="font-family:Verdana;">The capacity of a cold atmospheric-pressure air plasma (CAAP) device for advanced first aid is presented. Using swine as </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">animal model, two trials: 1) a large, curved cut in hindquarters area and 2)</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">amputation of a front leg, were perfo</span><span style="font-family:Verdana;">rmed. Cold atmospheric-pressure air plasma effluent, which carri</span><span style="font-family:Verdana;">es reactive oxygen species (ROS) atomic oxygen (OI), is applied for wound treatments. Swift hemostasis of the wounds by the CAAP treatment was demonstrated. The pressure applied by a finger on the cut arteries in trial 1 and the tourniquet applied in trial 2 could be removed immediately after the treatment and there was no re-bleed in both cases. CAAP hemostasis mechanism wa</span><span><span style="font-family:Verdana;">s explored via </span><i><span style="font-family:Verdana;">in</span></i><span style="font-family:Verdana;">-</span><i><span style="font-family:Verdana;">vitro</span></i><span style="font-family:Verdana;"> tests. The tests on sodium citrate mix</span></span><span style="font-family:Verdana;">ed blood-droplet samples show that 1) the heat delivered by the CAAP has no impact on the observed clot formation, 2) plasma effluent activates platelets to promote coagulation state and cascade, and 3) the degree of clotting increases with the total amount of applied OI by means of the CAAP effluent. It took only 16 s o</span><span style="font-family:Verdana;">f the CAAP treatment to reach full clotting, which was considerab</span><span style="font-family:Verdana;">ly shorten</span><span style="font-family:Verdana;">ed from the natural clotting time of about 25 minutes. The tests on</span><span style="font-family:Verdana;"> smeared blood samples show that the reduction of the platelet count and the increase of RBC count are proportional to the amount of applied OI. A plausible CAAP hemostasis mechanism is concluded from the in vitro test results and the animal model trials.</span></span>展开更多
Strom surges are not only determined by the atmospheric forcing,but also influenced by the coastal geometry and bathymetry.The Bohai Sea,as one of China’s marginal seas,is seriously harmed by storm surges,especially ...Strom surges are not only determined by the atmospheric forcing,but also influenced by the coastal geometry and bathymetry.The Bohai Sea,as one of China’s marginal seas,is seriously harmed by storm surges,especially those caused by cold-air outbreaks.As the coastline of the Bohai Sea has changed evidently these years,storm surges may have new characteristics due to the changes in the local geometry.This paper aims to find out these new characteristics by primarily investigating the influence of the changes in the local geometry on storm surges with numerical methods.20 scenarios were constructed based on the track and inten-sity of the cold-air outbreaks to describe the actual situation.By analyzing the model results of the control scenarios,it is found that the main changes of the maximum surge elevation occur in the Bohai Bay and the Laizhou Bay.At the top of the Bohai Bay,the maximum surge elevation is obviously decreased,while in the Laizhou Bay,it is enhanced by the growing Yellow River Delta.This,however,does not suggest that the storm surges in the Laizhou Bay become more serious.A comparison of the risk assessment of storm surges in the Tanggu,Huanghua and Yangjiaogou regions shows that the risk of storm surges in these coastal areas is lightened by the evolvement of the coastal geometry.Particularly near Yangjiaogou,though the maximum surge elevation becomes higher to subject more areas to risk,the risk is still reduced by the evolvement of the Yellow River Delta.展开更多
The NCEP/NCAR reanalysis data are used to investigate the role of cold air and moisture characteristics during the evolution of two cases of tropical cyclones (Nanmadol and Irma) which made landfall on China in winter...The NCEP/NCAR reanalysis data are used to investigate the role of cold air and moisture characteristics during the evolution of two cases of tropical cyclones (Nanmadol and Irma) which made landfall on China in wintertime. The results are shown as follows. (1) The East Asia trough steered the cold air into the tropical ocean in early winter. The tropical cyclones moved in opposite directions with a high moving out to sea and the enhancement of the pressure gradient at the periphery played a role in maintaining and strengthening the intensity of the storms. The intrusion of weak cold air into the low levels of the tropical cyclones strengthened them by improving the cyclonic disturbance when they were still over the warm sea surface. When the cold air was strong enough and intruded into the eyes, the warm cores were damaged and stuffed before dissipation. (2) The tropical cyclones were formed in a convergence zone of moisture flux and their development could enhance the disturbance of water vapor convergence, thus strengthening the moisture convergence zone. However, when they were outside the moisture zone, the storms could not gain sufficient water vapor and became weak. There were no belts of strong moisture transportation during the wintertime tropical cyclone processes.展开更多
State-of-the-art climate models have long-standing intrinsic biases that limit their simulation and projection capabilities. Significantly weak ENSO asymmetry and weakly nonlinear air-sea interaction over the tropical...State-of-the-art climate models have long-standing intrinsic biases that limit their simulation and projection capabilities. Significantly weak ENSO asymmetry and weakly nonlinear air-sea interaction over the tropical Pacific was found in CMIP5 (Coupled Model Intercomparison Project, Phase 5) climate models compared with observation. The results suggest that a weak nonlinear air-sea interaction may play a role in the weak ENSO asymmetry. Moreover, a weak nonlinearity in air-sea interaction in the models may be associated with the biases in the mean climate--the cold biases in the equatorial central Pacific. The excessive cold tongue bias pushes the deep convection far west to the western Pacific warm pool region and suppresses its development in the central equatorial Pacific. The deep convection has difficulties in further moving to the eastern equatorial Pacific, especially during extreme El Nifio events, which confines the westerly wind anomaly to the western Pacific. This weakens the eastern Pacific El Nifio events, especially the extreme E1 Nifio events, and thus leads to the weakened ENSO asymmetry in climate models. An accurate mean state structure (especially a realistic cold tongue and deep convection) is critical to reproducing ENSO events in climate models. Our evaluation also revealed that ENSO statistics in CMIP5 climate models are slightly improved compared with those of CMIP3. The weak ENSO asymmetry in CMIP5 is closer to the observation. It is more evident in CMIP5 that strong ENSO activities are usually accompanied by strong ENSO asymmetry, and the diversity of ENSO amplitude is reduced.展开更多
Employing the mesoscale WRF(Weather Research and Forecast) model, Super Typhoon Saomai(2006) is simulated. The variation of track and intensity and its offshore rapid intensification process are well demonstrated by t...Employing the mesoscale WRF(Weather Research and Forecast) model, Super Typhoon Saomai(2006) is simulated. The variation of track and intensity and its offshore rapid intensification process are well demonstrated by the model, and the temperature and humidity patterns associated with the dry cold air activity and their impact on and mechanism of the offshore rapid intensification of Saomai are mainly studied in this paper. The results indicate that high-resolution water vapor imagery can visually reveal the development, evolution, interaction as well as the mutual complementation of the dry cold air activity accompanied with the development of Saomai. The offshore rapid intensification phenomenon of Saomai is closely related to the dry cold air which originates from the upper- and mid-troposphere. Besides, the dry cold air from the upper troposphere is stronger than that from the mid-troposphere.Saomai intensifies as the dry cold air from the northwest moves toward its circulation but weakens when the dry cold air from the southwest is drawn into the storm. Dry cold airflows and their cold advection effect caused by the downward motion across the isentropic surface are favorable to the development of Saomai. The dry cold air always moves along an isentropic surface from the upper troposphere to the mid-troposphere around the typhoon circulation and contributes to Saomai's abrupt intensity change.展开更多
In this study, a novel approach to measure the absolute cytoplasmic Caconcentration([Ca]cyt) using the Caindicator fluo-3 AM was established. The parameters associated with the probe fluo-3 AM were optimized to accura...In this study, a novel approach to measure the absolute cytoplasmic Caconcentration([Ca]cyt) using the Caindicator fluo-3 AM was established. The parameters associated with the probe fluo-3 AM were optimized to accurately determine fluorescence intensity from the Ca-bound probe. Using three optimized parameters(final concentration of 6 m M probe,incubation time of 135 min, loading probe before plasma treatment), the maximum fluorescence intensity(F?=?527.8 a.u.) and the minimum fluorescence intensity(F?=?63.8 a.u.) were obtained in a saturated Casolution or a solution of lacking Ca. Correspondingly, the maximum [Ca]cytinduced by cold plasma was 1232.5 n M. Therefore, the Caindicator fluo-3 AM was successfully applied to measure the absolute [Ca]cytin Saccharomyces cerevisiae stimulated by cold plasma at atmospheric air pressure.展开更多
Taking a typical strong storm in Guizhou on April 5, 2017 for example, the diagnosis analysis used the water vapor cloud and the initial field of EC thin grid, including physical quantity, surface and upper air meteor...Taking a typical strong storm in Guizhou on April 5, 2017 for example, the diagnosis analysis used the water vapor cloud and the initial field of EC thin grid, including physical quantity, surface and upper air meteorological observation, as well as radar observation data. For the environment parameter analysis, small CAPE value tended to underestimate storm intensity on potential forecast stage, strong vertical wind shear revealed the strong dry cold air was the important intensity factors of the storm. The water vapor cloud map can be used to monitor the most important features, the dry zone, the wet zone and the boundary between them. When dry intrusion is found, it can be used as one of the bases for the development of heavy rain. Dry cold air intrusion on high-level was traced by water vapor images. And in this process, the analyses revealed the role of dry cold air’s influence on intensity of the storm.展开更多
The efficacy and mechanism of a cold atmospheric-pressure air plasma (CAAP), which carries abundant atomic oxygen (OI), on blood coagulation are studied. The tests on sodium citrate mixed blood-droplet samples show th...The efficacy and mechanism of a cold atmospheric-pressure air plasma (CAAP), which carries abundant atomic oxygen (OI), on blood coagulation are studied. The tests on sodium citrate mixed blood-droplet samples show that 1) The heat delivered by the CAAP has no impact on the observed clot formation, 2) Plasma effluent activates platelets to promote coagulation state and cascade, and 3) The degree of clotting increases with the OI flux delivered by the CAAP. The full clotting time is shortened from about 25 minutes of the natural clotting time to about 16 s of the CAAP treatment time. The tests on smeared blood samples show that the reduction of the platelet count and the increase of RBC count are proportional to the applied OI flux. In vivo tests, using swine as nimal model, swift hemostasis of large and deep cut wounds on the back by the CAAP treatment was demonstrated. A cut artery was sealed completely with 25 s treatment. The pressure applied by a finger on the cut artery could be removed immediately after the treatment and there was no re-bleed. Based on the in vitro test results and the animal model trials, CAAP coagulation mechanism is presented.展开更多
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences[grant numbers XDA23090102]the National Natural Science Foundation of China[grant numbers 42175078 and 42075040]+1 种基金the Health Meteorological Project of Hebei Province[grant number FW202150]the National Key Research and Development Program of China[grant number 2018YFA0606203].
文摘This paper used potential height field data published by the China National Climate Center and the US NCEP reanalysis data. A study was conducted on a strong cold wave weather process in central and eastern China from October 2 to 5, 2022. The results show that this weather process is a cold air weather process of “horizontal trough to vertical” type from the east of Novaya Zemlya Island. Cold air passes through Russia and Mongolia south, controlling northern China. The precipitation process is caused by the combination of high-altitude trough, ground front, warm and humid air flow, and precipitation weather formed by the influence of warm and humid air due to the 700 hPa shear line. The northern Sichuan Basin and the middle and lower reaches of the Yellow River in China can precipitate almost 50 mm. Water vapor is transported from the South China Sea to central and eastern China by the southwest warm and humid air flow along the west side of the West Pacific Subtropical High. Water vapor is concentrated over the precipitation area through horizontal convergence and is the most important source of water vapor causing precipitation.
文摘This study uses data provided by the National Meteorological Information Center of China, Japan Meteorological Agency (JMA) and National Oceanic Atmospheric Administration (NOAA) Physical Sciences Laboratory of the USA to analyze a cold air weather process at the beginning of January 2021. Synoptic analysis is mainly used to summarize synoptic laws or patterns based on observational data, and describe and infer weather processes. The main conclusions are as follows: The cold air travels south along the northwest path, affecting most of China. During the cold wave process, the first cold air is weak, which has a certain cooling effect on northern China. The second cold air was guided by the low vortex, the accumulation in the transverse groove of Mongolia was strengthened, and the cooling effect was significant. The southwest jet showed an increasing trend, and the water vapor transport conditions were good. However, due to the relatively gentle southern branch system, the warm and humid air flow was weak and the precipitation level was small. The purpose of this study is to better understand a large-scale cold air weather process in January 2021 in China.
文摘Based on the conventional meteorological data and the NCEP/NCAR 1° × 1° reanalysis data and those related to mid-scale automatic station, satellite cloud picture and radar return, with the dynamic diagnosis analysis method, an analysis is made on the process of the convective rainstorm of quasi-stationary front triggered by the weak cold air on June 4-7, 2014, showing: 1) the process occurred in the event of convection of a stationary front triggered by the eastward moving south trough and the southward moving weak cold air from west under the background of circulation of two ridges and one trough at the Asian-European mid-high latitude and weakening and southeastward moving subtropical high;2) a system configuration that contributes to convective rainstorms formed in the event of the convergence of low-level moisture, upper-level divergence and the continuous vertical ascending motion after the 200 hPa upper-level jet stream moved westwards from east and the 850 hPa southwest jet stream intensified;3) after the intrusion by weak cold air of the meso-scale katallobaric area formed by the accumulated warm moist air of Guangxi before the intrusion, the warm moist air rose to trigger convection;convection cells developed and spread nearby the boundary between anallobaric area and katallobaric area, during which total 5 MCSs developed and each formed a rainstorm center at the part where the MCSs coincide;a meso-scale katallobaric area forms and develops 2 - 5 hours earlier than convection, so that it is also a warning of heavy rains.
基金Meteorological Technology Special Opening Projects of Zhejiang Province (kf2010002)National Public Welfare Special Project of China (GYHY201206006)+2 种基金Planning Project for Key National Fundamental Research (2009CB421504)National Natural Science Foundation of China (41105062,40675033)Meteorological Technology Planning Projects of Zhejiang Province (2011ZD01)
文摘In 2005,significant rainfall reinforcement and severe disaster was induced by tropical cyclone(TC) Talim after it made landfall on the east of China.Observational analyses show that it has relationship with cold air intrusion.For investigating the impact of cold air intensity,we make use of Weather Research and Forecasting(WRF) model,the synthesizer of NCEP/NCAR reanalysis data and Japan regional spectral model data,to carry out numerical experiments.Results show that rainfall reinforcement occurs in all experiments.Different intensity of cold air can modify the rainfall distribution and intensity significantly.In the rainfall center,the increment maximum of rainfall is twice as large as that of the minimum.Moderate cold air intrusion may result in the strongest rainfall reinforcement.Different cold air intensity can lead to different motion of low-level convergence lines and fronts.There is a good relationship between the rainfall region and the eastern part of the front.On one hand,strong cold air weakens the TC intensity by its intrusion into the TC center and results in weak convergence and a convergent zone and a rain band shifted southward.On the other hand,weak cold air reduces the convergence and moves the convergent zone and rain band northward.Moderate cold air intrusion maintains strong low-level convergence and high-level divergence,keeping strong upward motion over certain regions.Consequently,the rain band begins to stagnate and rainfall reinforces abruptly therein.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40965001 and 40875008)the open project of State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences (Grant No.2009LASW-A02)
文摘In southern China, cold air is a common weather process during the winter season; it can cause strong wind, sharp temperature decreases, and even the snow or freezing rain events. However, the features of the atmospheric boundary layer during cold air passage are not clearly understood due to the lack of comprehensive observation data, especially regarding turbulence. In this study, four-layer gradient meteorological observation data and one-layer, 10-Hz ultrasonic anemometer-thermometer monitoring data from the northern side of Poyang Lake were employed to study the main features of the surface boundary layer during a strong cold-air passage over southern China. The results show that, with the passage of a cold air front, the wind speed exhibits low-frequency variations and that the wind systematically descends. During the strong wind period, the wind speed increases with height in the surface layer. Regular gust packets are superimposed on the basic strong wind flow. Before the passage of cold air, the wind gusts exhibit a coherent structure. The wind and turbulent momentum fluxes are small, although the gusty wind momentum flux is slightly larger than the turbulent momentum flux. However, during the invasion of cold air, both the gusty wind and turbulent momentum fluxes increase rapidly with wind speed, and the turbulent momentum flux is larger than the gusty wind momentum flux during the strong wind period. After the cold air invasion, this structure almost disappears.
文摘In order to improve the cold start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about the partial working processes of the diesel engine, the amount of heat energy, enough to make the fuel self ignite at the end of compression process at different temperatures of coolant and intake air, was calculated. Several HY20 preheating plugs were used to heat up the intake air. Meanwhile, an electronic control system based on 8 bit micro controller unit (MCS 8031) was designed to automatically control the process of heating intake air. According to the various temperatures of coolant and ambient air, one plug or two plugs can automatically be selected to heat intake air. The demo experiment validated that the total system could operate successfully and achieve the scheduled function.
基金Financial supports for this project, provided by the key program supported by the National Natural Science Foundation of China(No. 51134005)the Doctoral Scientific Fund Project of the Ministry of Education of China (No. 20120023120004), are gratefully acknowledged
文摘With the increase of mining depth, more and deeper coal mines are limited by heat disaster. The cooling energy in deep mine cooling system comes from mine water inrush or ground cooling tower, but we cannot adopt the two methods because mine water inrush in many old coal mines in China is limited. What is more, the cooling pipelines cannot be put in narrow pit-shaft. To settle the problem above, according to the characteristics of Zhangxiaolou Coal Mine, this paper adopts the deep mine return air as the cooling energy for deep mine cooling system. In addition, we carried out cite test to extract cold energy from return air. Through monitoring the water quantity, water temperature of cooling system and air temperature, we got the thermodynamic equilibrium parameters during the cooling energy acquisition analysis and the effect of cooling system that the temperature and humidity on working face are respectively reduced to 8-12 ℃ and 8-15% through cooling. This research offers experimental reference for deep mine cooling which lacks cooling energy.
基金Jiangsu Province Natural Science Fund(BK20131459)Science and Technology Department Social Development Project(BE2011818)+1 种基金National Meteorological Public Professional Science and Technology Program of China(GYHY201306010)National Sci-Tech Support Plan(2011BAK21B04)
文摘Based on intensive automatic weather station data, satellite cloud imagery, NCEP reanalyzed data, and the simulation results from mesoscale numerical models, this study analyzes the characteristics and formation mechanisms of the mesoscale convection system(MCS) during the extreme precipitation event that was triggered by a weakened low-pressure inverted trough of Typhoon Haikui on August 10/2012. The results of this study show that cold air at the rear of a northeastern cold vortex creates thermodynamic conditions favorable to the development of extreme precipitation. The main body of the cold air is northward located so that the cold air invades only the middle layer of the periphery of the inverted trough. Thus, the cold air minimally affects the lower layer, which results in a vertically distributed structure of the temperature advection that augments the formation and development of convective instability stratification. In the middle troposphere, the cold air encounters the convergent, ascending, warm moist air from the low-pressure inverted trough, leading to frontogenesis. The frontogenesis enhances wind convergence which, in turn, further enhances the frontogenesis, and the positive feedback between these two forces augments the development of meso- and small-scale convection systems in the rainstorm region and its vicinity, which strengthens the upward transportation of water vapor from low layers and thickening of water vapor convergence and results in local heavy rains.
基金supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government (MEST)(Grant No. 2011-0013879)supported by NSF (Grant Nos. AGS-0802888,AGS-1046171,and EEC-0313747)
文摘A 24-h simulation with the Advanced Regional Prediction System (ARPS) nonhydrostatic model is performed for the heavy snowfall event of 3-4 February 1998 along the eastern coast of Korean Peninsula; the results are used to understand the snowfall process, including why the precipitation maxima formed along the Yeongdong coastal region rather than over the mountain slope and ridge top during. The numerical simulation with a 4-kin horizontal grid spacing and 43 levels reproduces very well the narrow snowband located off the eastern Korean coast, away from, instead of over, the Yeongdong coastal mountain range. The general evolution of the snowband agrees quite well with radar observations, while the water-equivalent precipitation amount agrees reasonably well with radar precipitation estimate. The simulation results clearly show that the snow band developed due to the lifting by a coastal front that developed because of the damming of cold air against the eastern slope of the coastal mountain range. The damming was enhanced by the advection of cold air by a tow-level mountain-parallel jet from the north, formed due to geostrophic adjustment as the on-shore upslope air was decelerated by the mountain blocking. As the onshore flow weakened later due to synoptic-scale flow pattern change, the cold front propagated off shore and the precipitation dissipated.
基金Supported by National Natural Science Foundation of China(Nos.21246012,21306015 and 21476032)
文摘Air cold plasma has been used as a novel method for enhancing microbial fermentation. The aim of this work was to explore the effect of plasma on membrane permeability and the formation of ATP and NADH in Saccharomyces cerevisiae, so as to provide valuable information for largescale application of plasma in the fermentation industry. Suspensions of S. cerevisiae cells were exposed to air cold plasma for 0, 1, 2, 3, 4 and 5 min, and then subjected to various analyses prior to fermentation (Oh) and at the 9 and 21 h stages of fermentation. Compared with nonexposed cells, cells exposed to plasma for 1 min exhibited a marked increase in cytoplasmic free Ca2+ concentration as a result of the significant increase in membrane potential prior to fermentation. At the same time, the ATP level in the cell suspension decreased by about 40%, resulting in a reduction of about 60% in NADH prior to culturing. However, the levels of ATP and NADH in the culture at the 9 and 21 h fermentation stages were different from the level at 0 h. Taken together, the results indicated that exposure of S. cerevisiae to air cold plasma could increase its cytoplasmic free Ca2+ concentration by improving the cell membrane potential, consequently leading to changes in ATP and NADH levels.
文摘It is generally accepted that environmental factors can significantly influence respiratory system. Cold is one of these factors. Understanding of the reaction of airways to cold air is very important tool leading to improvement in management of cold induced rhinitis, cold induced asthma, exercise induced asthma, and exacerbation of chronic airway diseases induced by cold exposure. Despite the airways are protected against cold air by powerful heat and moisture exchanging counter current system within the nose, they are still at the risk of onset and development of cold induced symptoms mainly if this mechanism is insufficient, exposed person hyperventilates or is breathing subfreezing air. Some of the mechanisms involved in cold air induced reactions are understood quite well, but some of them are still discussed as they have not been satisfactorily explained, yet. Most discussed mechanisms by which cold air may induce respiratory symptoms include direct cooling and exsiccation of mucosal surface with subsequent hyper-tonicity of superficial fluid layer and interactions between the trigeminal and the vagus nerve at the central level. Molecular background for such a reaction may rely on the presence of thermo sensitive channels, mainly TRPM8, expressed on airway afferent nerves, which initiate response to cold air, giving a rise to autonomic responses like bronchoconstriction, cough, dyspnoea, chest tightness, mucus secretion and mucosal swelling. Identification of targets for cold action in the airway may help to identify potent antagonists which may prevent or reverse cold induced reactions sharing possibility for clinical application.
文摘<span style="font-family:Verdana;">The capacity of a cold atmospheric-pressure air plasma (CAAP) device for advanced first aid is presented. Using swine as </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">animal model, two trials: 1) a large, curved cut in hindquarters area and 2)</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">amputation of a front leg, were perfo</span><span style="font-family:Verdana;">rmed. Cold atmospheric-pressure air plasma effluent, which carri</span><span style="font-family:Verdana;">es reactive oxygen species (ROS) atomic oxygen (OI), is applied for wound treatments. Swift hemostasis of the wounds by the CAAP treatment was demonstrated. The pressure applied by a finger on the cut arteries in trial 1 and the tourniquet applied in trial 2 could be removed immediately after the treatment and there was no re-bleed in both cases. CAAP hemostasis mechanism wa</span><span><span style="font-family:Verdana;">s explored via </span><i><span style="font-family:Verdana;">in</span></i><span style="font-family:Verdana;">-</span><i><span style="font-family:Verdana;">vitro</span></i><span style="font-family:Verdana;"> tests. The tests on sodium citrate mix</span></span><span style="font-family:Verdana;">ed blood-droplet samples show that 1) the heat delivered by the CAAP has no impact on the observed clot formation, 2) plasma effluent activates platelets to promote coagulation state and cascade, and 3) the degree of clotting increases with the total amount of applied OI by means of the CAAP effluent. It took only 16 s o</span><span style="font-family:Verdana;">f the CAAP treatment to reach full clotting, which was considerab</span><span style="font-family:Verdana;">ly shorten</span><span style="font-family:Verdana;">ed from the natural clotting time of about 25 minutes. The tests on</span><span style="font-family:Verdana;"> smeared blood samples show that the reduction of the platelet count and the increase of RBC count are proportional to the amount of applied OI. A plausible CAAP hemostasis mechanism is concluded from the in vitro test results and the animal model trials.</span></span>
基金supported by the National Science and Technology Pillar Program during China's Eleventh Five-Year Plan Period (2006BAC03B01)
文摘Strom surges are not only determined by the atmospheric forcing,but also influenced by the coastal geometry and bathymetry.The Bohai Sea,as one of China’s marginal seas,is seriously harmed by storm surges,especially those caused by cold-air outbreaks.As the coastline of the Bohai Sea has changed evidently these years,storm surges may have new characteristics due to the changes in the local geometry.This paper aims to find out these new characteristics by primarily investigating the influence of the changes in the local geometry on storm surges with numerical methods.20 scenarios were constructed based on the track and inten-sity of the cold-air outbreaks to describe the actual situation.By analyzing the model results of the control scenarios,it is found that the main changes of the maximum surge elevation occur in the Bohai Bay and the Laizhou Bay.At the top of the Bohai Bay,the maximum surge elevation is obviously decreased,while in the Laizhou Bay,it is enhanced by the growing Yellow River Delta.This,however,does not suggest that the storm surges in the Laizhou Bay become more serious.A comparison of the risk assessment of storm surges in the Tanggu,Huanghua and Yangjiaogou regions shows that the risk of storm surges in these coastal areas is lightened by the evolvement of the coastal geometry.Particularly near Yangjiaogou,though the maximum surge elevation becomes higher to subject more areas to risk,the risk is still reduced by the evolvement of the Yellow River Delta.
基金National Development and Plan for Key Foundamental Research (2009CB421505)11th National Five-Year Plan for Science Support (2006BAC02B)+1 种基金National Natural Science Foundation (40775058)Natural Science Foundation of Guangxi (2010GXNSFA013010)
文摘The NCEP/NCAR reanalysis data are used to investigate the role of cold air and moisture characteristics during the evolution of two cases of tropical cyclones (Nanmadol and Irma) which made landfall on China in wintertime. The results are shown as follows. (1) The East Asia trough steered the cold air into the tropical ocean in early winter. The tropical cyclones moved in opposite directions with a high moving out to sea and the enhancement of the pressure gradient at the periphery played a role in maintaining and strengthening the intensity of the storms. The intrusion of weak cold air into the low levels of the tropical cyclones strengthened them by improving the cyclonic disturbance when they were still over the warm sea surface. When the cold air was strong enough and intruded into the eyes, the warm cores were damaged and stuffed before dissipation. (2) The tropical cyclones were formed in a convergence zone of moisture flux and their development could enhance the disturbance of water vapor convergence, thus strengthening the moisture convergence zone. However, when they were outside the moisture zone, the storms could not gain sufficient water vapor and became weak. There were no belts of strong moisture transportation during the wintertime tropical cyclone processes.
基金supported by the National Basic Research Program of China under the project“Structures,Variability and Climatic Impacts of Ocean Circulation and the Warm Pool in the Tropical Pacific Ocean”(Grant No.2012CB417401)the Strategic Priority Research Program–Climate Change:Carbon Budget and Related Issues,of the Chinese Academy of Sciences(Grant No.XDA05110302)+2 种基金the China Postdoctoral Science Foundation(Grant No.2012M521378)the Large-scale and Climate Dynamics Program of the U.S.National Science Foundation(AGS 0553111 and AGS 0852329)the Office of Global Programs of NOAA
文摘State-of-the-art climate models have long-standing intrinsic biases that limit their simulation and projection capabilities. Significantly weak ENSO asymmetry and weakly nonlinear air-sea interaction over the tropical Pacific was found in CMIP5 (Coupled Model Intercomparison Project, Phase 5) climate models compared with observation. The results suggest that a weak nonlinear air-sea interaction may play a role in the weak ENSO asymmetry. Moreover, a weak nonlinearity in air-sea interaction in the models may be associated with the biases in the mean climate--the cold biases in the equatorial central Pacific. The excessive cold tongue bias pushes the deep convection far west to the western Pacific warm pool region and suppresses its development in the central equatorial Pacific. The deep convection has difficulties in further moving to the eastern equatorial Pacific, especially during extreme El Nifio events, which confines the westerly wind anomaly to the western Pacific. This weakens the eastern Pacific El Nifio events, especially the extreme E1 Nifio events, and thus leads to the weakened ENSO asymmetry in climate models. An accurate mean state structure (especially a realistic cold tongue and deep convection) is critical to reproducing ENSO events in climate models. Our evaluation also revealed that ENSO statistics in CMIP5 climate models are slightly improved compared with those of CMIP3. The weak ENSO asymmetry in CMIP5 is closer to the observation. It is more evident in CMIP5 that strong ENSO activities are usually accompanied by strong ENSO asymmetry, and the diversity of ENSO amplitude is reduced.
基金National Natural Science Foundation of China(40730948,40875030,41475041)
文摘Employing the mesoscale WRF(Weather Research and Forecast) model, Super Typhoon Saomai(2006) is simulated. The variation of track and intensity and its offshore rapid intensification process are well demonstrated by the model, and the temperature and humidity patterns associated with the dry cold air activity and their impact on and mechanism of the offshore rapid intensification of Saomai are mainly studied in this paper. The results indicate that high-resolution water vapor imagery can visually reveal the development, evolution, interaction as well as the mutual complementation of the dry cold air activity accompanied with the development of Saomai. The offshore rapid intensification phenomenon of Saomai is closely related to the dry cold air which originates from the upper- and mid-troposphere. Besides, the dry cold air from the upper troposphere is stronger than that from the mid-troposphere.Saomai intensifies as the dry cold air from the northwest moves toward its circulation but weakens when the dry cold air from the southwest is drawn into the storm. Dry cold airflows and their cold advection effect caused by the downward motion across the isentropic surface are favorable to the development of Saomai. The dry cold air always moves along an isentropic surface from the upper troposphere to the mid-troposphere around the typhoon circulation and contributes to Saomai's abrupt intensity change.
基金supported by National Natural Science Foundation of China (Grant Nos. 21246012, 21306015 and 21476032)
文摘In this study, a novel approach to measure the absolute cytoplasmic Caconcentration([Ca]cyt) using the Caindicator fluo-3 AM was established. The parameters associated with the probe fluo-3 AM were optimized to accurately determine fluorescence intensity from the Ca-bound probe. Using three optimized parameters(final concentration of 6 m M probe,incubation time of 135 min, loading probe before plasma treatment), the maximum fluorescence intensity(F?=?527.8 a.u.) and the minimum fluorescence intensity(F?=?63.8 a.u.) were obtained in a saturated Casolution or a solution of lacking Ca. Correspondingly, the maximum [Ca]cytinduced by cold plasma was 1232.5 n M. Therefore, the Caindicator fluo-3 AM was successfully applied to measure the absolute [Ca]cytin Saccharomyces cerevisiae stimulated by cold plasma at atmospheric air pressure.
文摘Taking a typical strong storm in Guizhou on April 5, 2017 for example, the diagnosis analysis used the water vapor cloud and the initial field of EC thin grid, including physical quantity, surface and upper air meteorological observation, as well as radar observation data. For the environment parameter analysis, small CAPE value tended to underestimate storm intensity on potential forecast stage, strong vertical wind shear revealed the strong dry cold air was the important intensity factors of the storm. The water vapor cloud map can be used to monitor the most important features, the dry zone, the wet zone and the boundary between them. When dry intrusion is found, it can be used as one of the bases for the development of heavy rain. Dry cold air intrusion on high-level was traced by water vapor images. And in this process, the analyses revealed the role of dry cold air’s influence on intensity of the storm.
文摘The efficacy and mechanism of a cold atmospheric-pressure air plasma (CAAP), which carries abundant atomic oxygen (OI), on blood coagulation are studied. The tests on sodium citrate mixed blood-droplet samples show that 1) The heat delivered by the CAAP has no impact on the observed clot formation, 2) Plasma effluent activates platelets to promote coagulation state and cascade, and 3) The degree of clotting increases with the OI flux delivered by the CAAP. The full clotting time is shortened from about 25 minutes of the natural clotting time to about 16 s of the CAAP treatment time. The tests on smeared blood samples show that the reduction of the platelet count and the increase of RBC count are proportional to the applied OI flux. In vivo tests, using swine as nimal model, swift hemostasis of large and deep cut wounds on the back by the CAAP treatment was demonstrated. A cut artery was sealed completely with 25 s treatment. The pressure applied by a finger on the cut artery could be removed immediately after the treatment and there was no re-bleed. Based on the in vitro test results and the animal model trials, CAAP coagulation mechanism is presented.