Distribution Characteristics of Heavy Metals and Grain Size of Sediments from Hailing Bay, China

The geochemical properties of sediment in the nearby seawater areas of Hailing Bay of the western Guangdong province were first time investigated in the dry period of 2001 and the flood period of 2002, respectively. The temporal and spatial characteristics of Cu, Pb, Zn, Cd and Hg concentrations, organic carbon and total sulfides contents, and granulometric distribution in the surface sediment from the Hailing Bay were analyzed. Results demonstrated that there were no remarkable changes in the composition of sediment between the dry period and the flood period; the average concentrations of Cu, Pb, Zn, Cd and Hg were 32.1 ± 17.5, 36.1 ± 10.0, 107.0 ± 37.4, 0.26± 0.15 and 0.109 ± 0.073 mg·kg-1, respectively; the organic carbon and total sulfides contents were 1.33 ± 0.53 % and 140.13 ± 136.42 mg·kg-1, respectively; surface sediments were dominated by clayey silt and sand, and their mean grain size was 4.62 ± 2.36 φ and in the range 0.52-7.55 φ; there existed obvious correlation between the concentrations of Cu, Pb, Zn and Hg, and among Cu, Pb, Zn and Hg concentrations, organic carbon contents and grain size of sediments.

Study on the Seniors' Recreation in Coastal Regions from the Perspective of Wellness Tourism: A Case Study of Hailing Island

With the increasing proportion of the middle aged and elderly people,the aging of society has become a worldwide issue.Life experience and sufficient leisure time of the elderly are treasures of families and the whole society.The study focuses on improving life value and quality of the elderly,aims at ensuring them to enjoy highquality leisure life.Taking Hailing Island for example,health tourism resources on the island were analyzed,and health tourism development strategies summarized,and the elderly’leisure was explored from the perspective of health tourism,which is a brand-new perspective concerning the seniors and development of coastal tourism destinations.

Harm of Hail to Crops and Countermeasures of Artificial Hail Suppression in Ulanqab City

Hail is one of meteorological disasters affecting crop growth in Ulanqab City.It happens frequently from May to September,and this period is also the main growing season of crops.In this period,hail will cause damage to crops,make farmland soil harden,and bring varying degrees of harm to agricultural production.Artificial hail suppression is an important scientific and technological means for disaster prevention and mitigation.It is necessary to strengthen the monitoring,analysis and forecast of severe convection weather,intensify the release of early warning information of hail weather,provide accurate and reliable real-time information for the implementation of artificial hail suppression operations,strengthen the implementation of artificial weather modification,effectively carry out artificial hail suppression operations,and avoid and reduce the impact of hail disaster.

Analysis of a Large-scale Hail Process in Ulanqab City

Based on the weather monitoring data,NCEP/NCAR reanalysis data and Doppler weather radar data,the circulation background,atmospheric stability and changing characteristics of radar echoes of a large-scale hail weather process in Ulanqab City on July 5,2021 were analyzed.The results show that this hail weather process occurred in the summer afternoon of the hail-prone period in Ulanqab City,and was formed under the influence of upper trough and the circulation background of"two troughs and one ridge",which was conducive to the occurrence of strong convection weather.The low-level shear line provided the dynamic and water vapor conditions for the occurrence of the hail.In strong convection weather,water vapor was transported mainly from the Bay of Bengal,India and Nepal over the Himalayas.Before the occurrence of strong convection weather,water vapor transport increased significantly,and the low-level water vapor concentrated below 400 hPa,with obvious convergence and vertical transport.The characteristic parameters of radar echoes,such as combined reflectivity,vertically integrated liquid,and echo top height,increased significantly before and during the occurrence of hail,which had good indicative significance for the prediction and early warning of hail.

Risk Assessment of Hail Disaster on Cotton——A Case Study in Anhui Province

[Objective] The aim was to reveal the pattern of hail disaster risk for cotton in Anhui Province. [Method] Based on database of risk evaluation on hail disaster for cotton in Anhui Province, statistical inference and comprehensive indices measurement were made use of for extraction of disastrous index of hail （H） and loss rate of cotton （L）. Hail vulnerability curves in four stages （seedling, bud, boll and boll opening stages） of cotton were fitted by Matlab and SPSS software. Risk evaluation on hail disaster of cotton in Anhui Province was conducted and the related map was drawn on basis of yearly model of loss rate （by hail disaster）, as follows： Sa=n∑i=1Si-a∏i=1Si=1-（1-Si） [Result] In Anhui Province, high risk area by hail concentrates in northeast regions and mountainous regions in west of Anhui, and lower risk area is distributed in middle and down streams of Yangtze River and mountainous area in south of Anhui. [Conclusion] The research explored evaluation methods on hail risks based on the limited information, and could provide references for risk evaluation on hail disaster in other regions.

Analysis of Supercell Storm Structure and Mesocyclone Parameters

By using the high spatial and temporal resolution Jinan Doppler Weather Radar data and Jinan,Xingtai sounding data,the radar signature and mesocyclone parameters of 54 supercells during 2003-2008 were analyzed.The results showed that the probability of a supercell forming would be higher when SI (showalter index) ≤ -2℃,K (K index) ≥ 30℃ and 0-6 km wind shear>15 m/s.The supercell storms can generally be divided into two categories,namely,type of isolation and mosaic type.To the type of isolation,the max reflectivity,cell-based VIL,max reflectivity height,cell top,mesocyclone base and top were significantly higher than the mosaic type.Isolation-type supercells had significantly higher probability of hail,lower probability of gale than the mosaic category.The mesocyclone attribute differences between isolation-type and mosaic type supercells determined the differences of storm structures and severe weather phenomenon.

Analysis of Physical Quantities and Radar Parameters about Hail Shooting and Heavy Convective Rainfall

[Objective] The paper is to analyze physical quantities and radar parameter of hail shooting and heavy convective rainfall weather. [Method] Using radar data of Jinan station during 2002 and 2008, combined with sounding data, the physical quantities and radar parameter of hail shooting and heavy convective rainfall weather are compared and analyzed. [Result] The smaller Sl is conducive to the generation of hail weather. When K〉 35 ~C, the probability for occurrence of heavy rainfall weather is significantly increased; when K〈20 ^（3, the probability for occurrence of heavy rainfall weather is significantly decreased. When CAPE value is greater than 1 500 J/KG, the probability for occurrence of hail weather is significantly decreased, while the probability for occurrence of heavy rainfall weather is significantly in- creased. The possibility for occurrence of hail monomer is small when the wind shear is less than 5 m/s; and it is large while wind shear is greater than 20 m/s. The radar forecasting indexes of hail monomer is as follows： VIL value reaches 35 kg/m2 （May）, 43 kg/m2 （June and July）, the monomer height is greater than 9 km, the maximum reflectivity factor is larger than 60 dBz, strong center height reaches 3.3 km （May）, 4.3 km （June） and 5.5 km （July）; VlL value of heavy rainfall monomer generally is below 25 kg/m2. [Conclusion] The paper provides basis form prediction of hail and heavy rainfall.

3-D observations of a red tide event in the offshore water along the western Guangdong coast

From November 24 to 26, 2014, a red tide event occurred in the offshore water off the Hailing Island located at the western Guangdong coast. The red tide appeared as pink strips distributed within 3 km in the offshore water and extended for about 10 km along the shoreline. During the flood tide, the pink seawater rushed to the beach with breaking waves, forming foam strips on the beach. Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction Technologies, Guangdong Ocean University, emergently responded to the event and organized three-dimensional observations from the air, onboard and on beach. The preliminary analyses of the cruise data and water samples indicate that the event was induced by non- toxic Noctiluca scintillans, of which the concentration reaches as high as 4 200 cells/L near the surface and 2600 cells/L at the bottom.

Multi-Source Data Analyses of Processes of a Squall Line and the Gale Weather with Heavy Hails before the Squall Line

Through multi-source data analyses of regional automatic station data, wind profiling radar, lightning information, new-generation weather-radar echo data and conventional observations in Fujian Province, and others, this paper finds out aspects to focus on for potential forecasts and the nowcasting of wide-range gale weathers with thunderstorms and hail weathers in west Fujian Province on April 26th, 2016. Thus providing a basis for future forecasting of such catastrophic meteorological activities. Results of analyses showed that being affected by the eastward moving of upper troughs and the eastward and southward moving of low-level vortex shears, cold air and warm air strongly intersected in west Fujian Province;noticeable cold and warm advection formed the temperature frontal-zone;and under the triggering of the ground convergence line, impetuses formed by the strong convergent uplift before the south troughs forcibly produced wide-range squall lines, hails and other strong convective weathers. The squall line was caused by baroclinic frontogenesis. Hails with a diameter of up to 3 cm happened in the prefrontal warm zone. Supercells were generated and developed in the 80 km hot low-pressure convergence zone before the squall line moved along the direction at about 25° to the right of the mean wind field of the environment, belonged to right-shifting hailstorms, were of characteristics representing the hook echo and were of characteristics that the strength of the echo was high. On the afternoon of 26th, on the ground, temperature and humidity strongly increased. Fujian was located in the warm zone in the south side of the inverted trough. The specific humidity at 850 hPa was higher than 12 g/kg. The positive temperature change lasted for 24 hours. In the inland, the ridge was warm, while the trough was cold. Strong vertical wind shears that reached 20 m/s at 925 - 500 hPa and others were beneficial environmental conditions for forming the process of strong convective weather of baroclinic frontogenesis for this time.

Why Cycling in 2007 Was Faster than Being Driven in 2017 in Tianjin

Changes in the road environment of Tianjin were intended to speed up the traffic system and shift bicyclists to the metro,bus and car.The metro system was greatly expanded,along with a modernized bus fleet.App-based taxi services were also introduced.In 2007,travellers to the central area were intercepted to determine the starting point of their trip and their travel mode.The most time-efficient trips in 2007 were by bicycle(61%).These trips were re-enacted in 2017 using taxi and metro as it was no longer physically possible to replicate most of the original bicycle trips.Trips greater than 5 km in distance were somewhat faster by taxi than they were by bicycle,but overall,travel time by taxi was greater than by the bicycle for those same trips in 2007.A network analysis of road changes provides explanation why longer trips became more efficient while short trips became less efficient.Travel by metro alone was much longer than the other two methods,but the combination of app-based bicycles and metro would render this travel method the most efficient.

Diagnostic Analysis on A Hail Storm Occurred in Dalian Area

By using regular meteorological data and Doppler radar data,causes for a hail storm over northern area of Dalian on Oct.13,2009 were analyzed from several aspects,including synoptic background,T-LnP charts and the characteristics of radar reflectivity factor evolution.The results showed that the hail storm occurred in downstream of 500 hPa trough.The 500 hPa cold trough turned zonally and triggered the formation of shear line on lower level.Before the hail event,instability energy and moisture supply were observed.The shear line on lower level intensified the atmospheric instability,promoted the release of potential energy,caused the hail event.The cooperation of upper and lower level jet streams provided favorable dynamic condition for strong convection development.The Doppler radar analysis showed that strong convection was comprised of multiple convection cells,which demonstrated 'L' and 'V' shapes during mature stage,with peak intensity of 50-60 dBz.

The Role of Initial Cloud Condensation Nuclei Concentration in Hail Using the WRF NSSL 2-moment Microphysics Scheme

The effects of the initial cloud condensation nuclei （CCN） concentrations （100-3000 mg-1） on hail properties were investigated in an idealized non-severe hail storm experiment using the Weather Research and Forecasting （WRF） model, with the National Severe Storms Laboratory 2-moment microphysics scheme. The initial CCN concentration （CCNC） had obvious non-monotonic effects on the mixing ratio, number concentrations, and radius of hail, both in clouds and at the surface, with a CCNC threshold between 300 and 500 mg-1. An increasing CCNC is conducive （suppressive） to the amount of surface hail precipitation below （above） the CCNC threshold. The non-monotonic effects were due to both the thermodynamics and microphysics. Below the CCNC threshold, the mixing ratios with the increasing CCNC, resulting in more latent heat released of cloud droplets and ice crystals increased dramatically from condensation and frozen between 4 and 8 km and intensified updraft volume. The extent of the riming process, which is the primary process for hail production, increased dramatically. Above the CCNC threshold, the mixing ratio of cloud droplets and ice crystals increased continuously, but the maximum updraft volume was weakened because of reduced frozen latent heating at low level. The smaller ice crystals reduced the formation of hail and smaller clouds, with decreased rain water reducing riming efficiency so that graupel and hail also decreased with increasing CCNC, which is unfavorable for hail growth.

Prevalence of intestinal parasite infections among patients in local public hospitals of Hail,Northwestern Saudi Arabia

Objective:To evaluate the prevalence of intestinal parasites among patients in Hail,Northwestern Saudi Arabia.Methods:Stool samples were collected from 130 patients(69females and 61 males) in Hail General Hospital.Each sample was examined by direct wet mount microscopic examination using both normal saline and Lugol's iodine preparation and concentration techniques using salt and formol-ether solutions.Permanent stained smears were performed for intestinal coccidian using modified Ziehl-Neelsen technique.Results:The overall prevalence of intestinal parasitic infection was 45.38%(59 cases).Forty-four(33.84%)were found to be infected with one or more intestinal protozoa.5(3.84%) were infected with helminthes and 10(7.69%) had mixed infection with both helminthes and protozoa.The most common intestinal helminth detected was Ancyloxtoma duvdenale(n=5.3.84%),followed by Ascaris lumlmcnidex.Taenia sp.and Trichuris trichiura(n=2 for each species,1.5%).For intestinal protozoa,the coccidian Cryptosporidium parvum(n=25,19.23%) was the most common followed by Entamoeba histolytica/dispur(n=21,16.15%),Giurdia lamblia(n=15,11.54%),Entamoeba coli(n=5.3.85%) and Blastocysts hominis(n=3,2.30%).The prevalence of intestinal parasitic infections in females was significantly higher than in males(P<0.05).Conclusions:This is the first study highlighting that intestinal parasites are still an important public health problem in Northwestern Saudi Arabia Therefore,health education would be the best way to prevent from intestinal parasite infections which are mainly food borne diseases.

Diagnosis of An Infrequent Regional Hail Weather Course in Gansu

Based on routine weather charts, numerical predication products and satellite cloud images, the causes of an infrequent regional hail weather process occurred in east of Gansu on Aug. 2, 2006 were diagnosed and analyzed. The results showed that the hail weather process occurred at the abnormal large-scale circulation leading the system to west. When the cold trough, which was separated by the north cold vortex, moved southward through Hetao and then intersected with 300 hPa jet stream and the surface cold front, that led to the strong convection. There were strong upward motion and unstable stratification in hail area, three MCS in satellite cloud, and a character of formed arch shape echo on radar echo charts.

Analysis on the Hail Climate and Radar Characteristics in Linyi City

[Objective] The research aimed to study the hail climate and radar characteristics in Linyi City.[Method] The five representative stations which were Mengyin,Yishui,Linshu,Cangshan,Linyi and were collectively called as Linyi City in Yimeng mountain area were selected.From the hail path,weather situation and influence system,the 40 times hail weather processes which happened in every station in June during 1965-2008 were carried out the statistics analysis.The typical weather situation and physical structure characteristics in the hail weather process in Linyi City were studied.On this basis,the statistical analysis on the new generation weather radar characteristics in the hail process during 2003-2008 was carried out.The climatic index of hail occurrence,the characteristic index of radar data and the radar observation characteristic in the city were discussed.[Result] The weather systems which affected the hail shooting in Linyi City were Mongolia cold vortex type,eastward shift small trough type,northwest airflow cold temperature trough type and so on.On the 6 h ground chart before the hail shooting,there were the small low pressure,cold front or wind shear line(airflow convergence field) in Shandong Province.They had the 'trigger' and 'development' effects on the occurrence and development of strong convection hail shooting.The joining of small trough in the rear of 500 hPa low vortex had three forms that were the west small trough supplementary type,the airflow field divergence in front of vortex and the small trough in the rear of vortex southward swing in general.When the vertical liquid water content quickly increased from zero or the small amount to above 40 kg/m2,it was possible to generate the hail weather.In the different months,when the echo intensity of convective cloud body >50 dBz,the initial echo height >5 km,and the crown elevation,strong center height reached the certain values,it was possible to generate the hail weather.On the radar radial velocity chart,the meso-scale convective system characteristic(the bottom layer was the convergence,and the high layer was the divergence) was obvious.At 1.5° and 3.4° elevation angles in the middle layer,there was the strong wind shear in the vertical direction of convective storm monomer.[Conclusion] The research provided the certain reference value for the analysis and forecast of this kind of weather.

Climatic Characteristics of Hail Disaster and Division of Defense Region in Guizhou Province

[Objective] The aim was to study the climatic characteristics of hail disaster from 1984 to 2006 in Guizhou Province,China.[Method] Through statistical analysis,the climatic characteristics and disaster characteristics of hail from 1984 to 2006 in Guizhou Province were annalyzed and compared with previous results,then the classification standards of hail disaster were established,finally the defense zoning map of hail disaster in Guizhou Province was made.[Result] According to the statistical analysis on the historical data of hail disaster from 1984 to 2006,the frequency hail was 1 243 times in Guizhou in 23 years,that is,annual average frequency reached 54 times;annual average hailing days were 0.1-2.7 d in Guizhou Province,and the average frequency of hail was 3.8 times during each hail process;the frequency of hail was below 30 times in 52% of years and 30-80 times in 35% of years among 23 years.Hail could appear in the whole year,and 74% of hails occurred in spring,while winter had the fewest times.The results above were basically consistent with those of previous studies.Hail disaster mainly resulted in casualties and direct economic loss,and was divided into four grades according to direct economic loss,namely Grade I(extremely severe hail disaster),Grade II(severe hail disaster),Grade III(comparatively severe hail disaster) and Grade IV(medium hail disaster).The defense zoning map of hail disaster in Guizhou Province was made based on the frequency of hail and severe hail disaster,that is,the defense region at Grade I mainly distributed in Liupanshui City(in western Guizhou) and southern Guizhou;the defense region at Grade II was in the west,south and northeast of Guizhou Province,while the rest was at Grade III.[Conclusion] The study was of reference value for the defense of hail disaster in Guizhou Province.

Temporal-spatial Distribution and Short-range Prediction Indicators of Hail Weather in East Central Haixi Prefecture of Qinghai Province

[ Objective] The study aimed to discuss the temporal-spatial distribution and short-range prediction indicators of hail weather in east central Haixi Prefecture of Qinghai Province. [Method] Using hail data of six stations in east central Haixi Prefecture from 1960 to 2010, the temporal and spatial distribution of hail weather was analyzed firstly. Afterwards, based on the high-altitude factual data of 30 case studies of hail during 2006 -2010, its high-altitude and ground weather situation and physical quantity field were studied to summarize short-term circulation pattern and shod- range prediction characteristics of hail weather. [ Result] In east central Haixi, hail appeared from April to September, and it was most frequently from May to August. Meanwhile, hail was frequent from 14：00 to 20：00. Among the six stations, hail was most frequent in Tianjun but least frequent in Wulan. Moreover, hail disaster mainly occurred in Wulan and Tianjun. In addition, there were three typos of circulation pattern of hail weather at 500 hPa. Hail mainly occurred under the effect of northwest airflow, and it had shortwave trough, cold center or trough, jet stream core or one of the three. Hail appeared frequently under the situation of upper-level divergence and low-level convergence, and abundant water vapor and water vapor flux convergence at low levels were important conditions for hailing. [ Conclusion] The research could provide scientific references for improving the accuracy of hail forecast.

Analysis on the Climatic Characteristics of Hail in the South Mountain Area of Ningxia

[Objective] The research aimed to study the climatic characteristics of hail in the southern mountain area of Ningxia in recent 50 years. [Method] Based on the hail observation data of 5 surface meteorological stations (Guyuan, Xiji, Jingyuan, Longde, Liupanshan) in the south of Ningxia during 1960-2009, the spatial distribution rule, the interannual and monthly climatic characteristics and variation trends of hail in the south mountain area of Ningxia were analyzed by using the statistical method. Moreover, the hail disaster prevention and reduction measures in Guyuan were put forward. [Result] The hail in the south mountain area of Ningxia in recent 50 years had the obvious annual, seasonal, monthly and daily variation characteristics. The hail might occur from March to October and mainly concentrated during May-August which occupied 72% in the whole year. The occurrence probability of hail in June was the biggest and occupied 21.7% in the whole year. It was the typical multi-hail zone in summer. The interannual variation of hail occurrence in Guyuan was big and had 3-year periodicity. The secondary-order time trend of hail in Guyuan was the anti-parabolic type, and the hail occurrence times during the 1960s-1980s presented the increase trend. It was the hail multi-occurrence period in the 1970s and 1980s. After the 1990s, the hail presented the decrease trend. In recent 20 years, the hail significantly decreased. The hail in Guyuan mainly concentrated during 12:00-21:00, and the hail occurrence times occupied 85% of total times. The hail distribution in Guyuan area had the obvious regional characteristics. The hail in the mountain area, hilly area was more and in the stream valley, north Pingchuan area was less. The hail cloud mainly derived from the mountain areas, such as Liupanshan, Nanhua Mountain, Yueliang Mountain, Xifeng Mountain and Yunwu Mountain, etc. The move direction of hail cloud was mainly from northwest to southeast or from north to south. Part of hail cloud disappeared in the original place. According to the regional distribution of hail, the hail risk in Guyuan City was divided into the high, moderate and low occurrence zones by combining with the hail disaster data. [Conclusion] The research provided the scientific basis for the forecast, early-warning of hail weather and the artificial hail suppression.

Growth and yield responses to simulated hail damage in drip-irrigated cotton

The frequent occurrence of hailstorm in Xinjiang affects cotton(Gossypium hirsutum L.)production and causes enormous economic loss.The indeterminate growth habit of cotton allows for varying degrees of recovery and yield when different hail damage levels occur at different stages,which brings inconvenience to agricultural insurance claims and post-damage management.Therefore,this study aimed to elucidate cotton recovery and yield responses to different levels of simulated hail damage at different growth stages.Four levels of hail damage(0,30,60,and 90%)were simulated every 15 d from the five-leaf stage to the boll opening stage in 2018 and 2019,for a total of six times(Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ,and Ⅵ).The results showed that seed cotton yield decreased as the damage level increased and yield reduction increased when the damage was applied to older plants(for 30,60 and 90% damage levels,yield reduction was 9-17%,22-37% and 48-71%,respectively).One possible reason was that the leaf area index and leaf area duration of plant canopy decreased after hail damage,resulting in a reduction in the accumulation of above-ground biomass.However,when hail damage occurred before bloom,due to the indeterminate growth habit of cotton,the vegetative organs produced a strong compensation ability that promoted the bud development.The compensation ability of vegetative organs decreased when hail damage occurred after bloom and the recovery time was too short to promote new boll maturity.As the first study to understand the recovery of cotton after hail damage,it analyzed the leaf area index,leaf area duration,above-ground biomass accumulation and yield,rather than the yield alone.The findings are of great importance for cotton production as they inform decisions about post-damage management practices,yield forecasts and insurance compensation.