Differences in spring precipitation over southern China associated with multiyear La Ni?a events

Composite analyses were performed in this study to reveal the difference in spring precipitation over southern China during multiyear La Ni?a events during 1901 to 2015. It was found that there is significantly below-normal precipitation during the first boreal spring, but above-normal precipitation during the second year. The difference in spring precipitation over southern China is correlative to the variation in western North Pacific anomalous cyclone(WNPC), which can in turn be attributed to the different sea surface temperature anomaly(SSTA) over the Tropical Pacific. The remote forcing of negative SSTA in the equatorial central and eastern Pacific and the local air-sea interaction in the western North Pacific are the usual causes of WNPC formation and maintenance.SSTA in the first spring is stronger than those in the second spring. As a result, the intensity of WNPC in the first year is stronger, which is more likely to reduce the moisture in southern China by changing the moisture transport, leading to prolonged precipitation deficits over southern China. However, the tropical SSTA signals in the second year are too weak to induce the formation and maintenance of WNPC and the below-normal precipitation over southern China. Thus, the variation in tropical SSTA signals between two consecutive springs during multiyear La Ni?a events leads to obvious differences in the spatial pattern of precipitation anomaly in southern China by causing the different WNPC response.

Diversity on the Interannual Variations of Spring Monthly Precipitation in Southern China and the Associated Tropical Sea Surface Temperature Anomalies

There is a continuous and relatively stable rainy period every spring in southern China(SC).This spring precipitation process is a unique weather and climate phenomenon in East Asia.Previously,the variation characteristics and associated mechanisms of this precipitation process have been mostly discussed from the perspective of seasonal mean.Based on the observed and reanalysis datasets from 1982 to 2021,this study investigates the diversity of the interannual variations of monthly precipitation in spring in SC,and focuses on the potential influence of the tropical sea surface temperature(SST)anomalies.The results show that the interannual variations of monthly precipitation in spring in SC have significant differences,and the correlations between each two months are very weak.All the interannual variations of precipitation in three months are related to a similar western North Pacific anomalous anticyclone(WNPAC),and the southwesterlies at the western flank of WNPAC bring abundant water vapor for the precipitation in SC.However,the WNPAC is influenced by tropical SST anomalies in different regions each month.The interannual variation of precipitation in March in SC is mainly influenced by the signal of El Nino-Southern Oscillation,and the associated SST anomalies in the equatorial central-eastern Pacific regulate the WNPAC through the Pacific-East Asia(PEA)teleconnection.In contrast,the WNPAC associated with the interannual variation of precipitation in April can be affected by the SST anomalies in the northwestern equatorial Pacific through a thermally induced Rossby wave response.The interannual variation of precipitation in May is regulated by the SST anomalies around the western Maritime Continent,which stimulates the development of low-level anomalous anticyclones over the South China Sea and east of the Philippine Sea by driving anomalous meridional vertical circulation.

A Statistical Linkage between Extreme Cold Wave Events in Southern China and Sea Ice Extent in the Barents-Kara Seas from 1289 to 2017

Arctic sea ice loss and the associated enhanced warming has been related to midlatitude weather and climate changes through modulate meridional temperature gradients linked to circulation. However, contrasting lines of evidence result in low confidence in the influence of Arctic warming on midlatitude climate. This study examines the additional perspectives that palaeoclimate evidence provides on the decadal relationship between autumn sea ice extent (SIE) in the Barents-Kara (B-K) Seas and extreme cold wave events (ECWEs) in southern China. Reconstruction of the winter Cold Index and SIE in the B-K Seas from 1289 to 2017 shows that a significant anti-phase relationship occurred during most periods of decreasing SIE, indicating that cold winters are more likely in low SIE years due to the “bridge” role of the North Atlantic Oscillation and Siberian High. It is confirmed that the recent increase in ECWEs in southern China is closely related to the sea ice decline in the B-K Seas. However, our results show that the linkage is unstable, especially in high SIE periods, and it is probably modulated by atmospheric internal variability.

The Response of Anomalous Vertically Integrated Moisture Flux Patterns Related to Drought and Flood in Southern China to Sea Surface Temperature Anomaly

With the extreme drought(flood)event in southern China from July to August in 2022(1999)as the research object,based on the comprehensive diagnosis and composite analysis on the anomalous drought and flood years from July to August in 1961-2022,it is found that there are significant differences in the characteristics of the vertically integrated moisture flux(VIMF)anomaly circulation pattern and the VIMF convergence(VIMFC)anomaly in southern China in drought and flood years,and the VIMFC,a physical quantity,can be regarded as an indicative physical factor for the"strong signal"of drought and flood in southern China.Specifically,in drought years,the VIMF anomaly in southern China is an anticyclonic circulation pattern and the divergence characteristics of the VIMFC are prominent,while those are opposite in flood years.Based on the SST anomaly in the typical draught year of 2022 in southern China and the SST deviation distribution characteristics of abnormal draught and flood years from 1961 to 2022,five SST high impact areas(i.e.,the North Pacific Ocean,Northwest Pacific Ocean,Southwest Pacific Ocean,Indian Ocean,and East Pacific Ocean)are selected via the correlation analysis of VIMFC and the global SST in the preceding months(May and June)and in the study period(July and August)in 1961-2022,and their contributions to drought and flood in southern China are quantified.Our study reveals not only the persistent anomalous variation of SST in the Pacific and the Indian Ocean but also its impact on the pattern of moisture transport.Furthermore,it can be discovered from the positive and negative phase fitting of SST that the SST composite flow field in high impact areas can exhibit two types of anomalous moisture transport structures that are opposite to each other,namely an anticyclonic(cyclonic)circulation pattern anomaly in southern China and the coastal areas of east China.These two types of opposite anomalous moisture transport structures can not only drive the formation of drought(flood)in southern China but also exert its influence on the persistent development of the extreme weather.

Precipitation Microphysical Characteristics of Typhoon Ewiniar(2018) before and after Its Final Landfall over Southern China

In this paper, the evolution of the microphysical characteristics in different regions(eyewall, inner core, and outer rainbands) and different quadrants [downshear left(DL), downshear right(DR), upshear left(UL), and upshear right(UR)]during the final landfall of Typhoon Ewiniar(2018) is analyzed using two-dimensional video disdrometer and S-band polarimetric radar data collected in Guangdong, China. Due to the different types of underlying surfaces, the periods before landfall(mainly dominated by underlying sea surface) and after landfall(mainly dominated by underlying land surface) are also analyzed. Both before landfall and after landfall, the downshear quadrants had the dominate typhoon precipitation. The outer rainbands had more graupel than the inner core, resulting in a larger radar reflectivity, differential reflectivity, specific differential phase shift, and mass-weighted mean diameter below the melting layer. Compared with other regions, the eyewall region had the smallest mean logarithmic normalized intercept parameter before landfall and the smallest mean mass-weighted mean diameter and the largest mean logarithmic normalized intercept parameter after landfall. The hydrometeor size sorting was obvious in the eyewall and inner core(especially in the eyewall) after landfall. A high concentration of large raindrops fell in the DL quadrant, and more small raindrops fell in the UR quadrant. Although the icephase process and warm rain process were both important in the formation of tropical cyclone precipitation, the warm rain process(ice-phase process) contributed more liquid water before landfall(after landfall). This investigation provides a reference for improving the microphysical parameterization scheme in numerical models.

Characteristics and Affinity of Tropical Flora in Southern China

The tropical flora in southern China is represented mainly by three regional flora, i.e. southern Yunnan (southwestern China), southwestern Guangxi (southwestern China) and Hainan Island (southern China). The floristic composition of each is concisely enumerated. Their geographical elements at generic level are analyzed. Furthermore, a comparison of floristic similarities between southern Yunnan and Hainan Island and Malay Peninsula and Brunei of western Malesia is made, based on existing regional flora treatments. The following is concluded: (1) The flora of southern China consists mainly of tropical floristic elements which contribute about 60% at the family level and more than 80 % at the generic level of its total flora. The dominant distribution type of the flora of southern China at the generic level is the tropical Asian distribution pattern. This reveals that the flora of southern China is of tropical nature with a strong tropical Asian affinity; (2) Most of the dominant families from the flora of southern China are also dominant in the Malesian flora. The floristic similarities between the regional flora of southern China and the regional flora of western Malesia are over 70% at the family level and more than 50% at the generic level. This suggests that the tropical flora of southern China belongs to the Malesian floristic region; (3) Situated at the northern margin of tropical Asia, on the other hand it is also obvious that the flora of southern China comprises less strictly tropical elements compared to the Malesian flora, and is consequently only a marginal type of the latter; (4) The close affinity of the flora of southern China to the Malesian flora can be explained by the geological history of southeast Asia.

Study of liver cirrhosis over ten consecutive years in Southern China

AIM: To investigate the etiology and complications of liver cirrhosis (LC) in Southern China.

Evolution of Intraseasonal Oscillation over the Tropica lWestern Pacific/South China Sea and Its Effect to the Summer Precipitation in Southern China

In this paper, the evolution of intraseasonal oscillation over the South China Sea and tropical western Pacific area and its effect to the summer rainfall in the southern China are studied based on the ECMWF data and TBB data) analyses. A very low-frequency waves exist in the tropics and play an important role in dominating intraseasonal oscillation and lead to special seasonal variation of intraseasonal oscillation over the South China Sea/tropical western Pacific area. The intraseasonal oscillation (convection) over the South China Sea and tropical western Pacific area is closely related to the summer rainfall (convection) in the southern China. Their relationship seems to be a seesaw feature, and this relationship resulting from the different pattern of convection in those two regions is caused by the differnt type of local meridional circulation.

Characteristics of the Boundary Layer Structure of Sea Fog on the Coast of Southern China

Using boundary layer data with regard to sea fog observed at the Science Experiment Base for Marine Meteorology at Bohe,Guangdong Province,the structure of the atmospheric boundary layer and the characteristics of the tops of the fog and the clouds were analyzed.In addition,the effects of advection,radiation,and turbulence during sea fog were also investigated.According to the stability definition of saturated,wet air,the gradient of the potential pseudo-equivalent temperature equal to zero was defined as the thermal turbulence interface.There is evidence to suggest that two layers of turbulence exist in sea fog.Thermal turbulence produced by long-wave radiation is prevalent above the thermal turbulence interface,whereas mechanical turbulence aroused by wind shear is predominant below the interface.The height of the thermal turbulence interface was observed between 180 m and 380 m.Three important factors are closely related to the development of the top of the sea fog：（1） the horizontal advection of the water vapor,（2） the long-wave radiation of the fog top,and（3） the movement of the vertical turbulence.Formation,development,and dissipation are the three possible phases of the evolution of the boundary-layer structure during the sea fog season.In addition,the thermal turbulence interface is the most significant turbulence interface during the formation and development periods;it is maintained after sea fog rises into the stratus layer.

Role of the Subtropical Westerly Jet Waveguide in a Southern China Heavy Rainstorm in December 2013

An extreme rainstorm hit southern China during 13–17 December 2013, with a record-breaking daily rainfall rate, large spatial extent, and unusually long persistence. We examined what induced this heavy rainfall process, based on observed rainfall data and NCEP–NCAR reanalysis data through composite and diagnostic methods. The results showed that a Rossby waveguide within the subtropical westerly jet caused the event. The Rossby wave originated from strong cold air intrusion into the subtropical westerly jet over the eastern Mediterranean. With the enhancement and northward shift of the Middle East westerly jet, the Rossby wave propagated slowly eastward and deepened the India–Burma trough, which transported a large amount of moisture from the Bay of Bengal and South China Sea to southern China. Strong divergence in the upper troposphere, caused by the enhancement of the East Asian westerly jet, also favored the heavy rainfall process over Southeast China. In addition, the Rossby wave was associated with a negative-to-positive phase shift and enhancement of the North Atlantic Oscillation, but convergence in the eastern Mediterranean played the key role in the eastward propagation of the Rossby wave within the subtropical westerly jet.

Stable isotopes of summer monsoonal precipitation in southern China and the moisture sources evidence from δ^18O signature

Summer monsoons （South Asian monsoon, South China Sea monsoon and Subtropical monsoon） are prominent features of summertime climate over southern China. Dif- ferent monsoons carry different inflow moisture into China and control the temporal and spatial distributions of precipitation. Analyses of meteorological data, particularly wind, tempera- ture and pressure anomalies are traditional methods of characterizing moisture sources and transport patterns. Here, we try to utilize the evidence from stable isotopes signatures to trace summer monsoons over southern China. Based on seven CHNIP （Chinese Network of Iso- topes in Precipitation） observatory stations located in southern China, monthly composite precipitation samples have been collected and analyzed for the composition of δ^18O during July, 2005. The results indicated that the spatial distributions of δ^18O in precipitation could properly portray the moisture sources together with their transport pathways. Moreover, the amount effect, altitude effect, temperature effect and the correlation between δ^18O vs. relative humidity were discussed.

Identification and Typing of Respiratory Adenoviruses in Guangzhou, Southern China Using a Rapid and Simple Method

Human adenoviruses (HAdVs), especially HAdV-B3, -E4 and -B7, are associated with Acute Respiratory Disease in Chinese children, and occasionally in adults. In order to establish and document the profiles of the respiratory adenovirus pathogen among children in Guangzhou, Southern China, a rapid, simple and practical method for identification and typing of respiratory adenoviruses was developed and evaluated. One pair of universal PCR primers was designed according to the conserved region of the hexon gene, which can detect not only HAdV-B3, -E4 and -B7, but also HAdV-B14, -F40 and -F41, with a specific 300bp PCR product. Three pairs of type-specific PCR primers were also designed according to the hypervariable regions of the hexon gene to type HAdV-B3, -E4 and -B7 by three independent PCR reactions, making it easy to optimize the PCR conditions. By using this method, one hundred throat swab specimens collected during Oct 2010 to Dec 2011 and suspected of being positive for adenoviral infection were identified and typed for adenoviruses. Of these samples, fifty-five were adenovirus-positive. The most common HAdV type was HAdV-B3, identified in 92.7% of samples, which is not only consistent with the data reported in 2004-2006, but also consistent with the recent report in Hangzhou, eastern China, indicating that HAdV-B3 has been circulating in Guangzhou, and maybe in eastern China, for many years. The method for the respiratory adenovirus identification and typing we developed is rapid, simple and practical, which has a potential in the real-time surveillance of circulating adenovirus strains and also to provide etiological evidence for the adenovirus-relative disease control and prevention in China.

Evaluating the grassland net primary productivity of southern China from 2000 to 2011 using a new climate productivity model

Grassland is the important component of the terrestrial ecosystems. Estimating net primary productivity （NPP） of grassland ecosystem has been a central focus in global climate change researches. To simulate the grassland NPP in southern China, we built a new climate productivity model, and validated the model with the measured data from different years in the past. The results showed that there was a logarithmic correlation between the grassland NPP and the mean annual temperature, and there was a linear positive correlation between the grassland NPP and the annual precipitation in southern China. Al these results reached a very signiifcant level （P〈0.01）. There was a good correlation between the simulated and the measured NPP, withR2 of 0.8027, reaching the very signiifcant level. Meanwhile, both root mean square errors （RMSE） and relative root-mean-square errors （RRMSE） stayed at a relatively low level, showing that the simulation results of the model were reliable. The NPP values in the study area had a decreasing trend from east to west and from south to north, and the mean NPP was 471.62 g C m？2 from 2000 to 2011. Additionaly, there was a rising trend year by year for the mean annual NPP of southern grassland and the tilt rate of the mean annual NPP was 3.49 g C m？2 yr？1 in recent 12 years. The above results provided a new method for grassland NPP estimation in southern China.

Clinicopathological features and trend changes of gastric carcinoma in Southern China

AIM: To investigate the clinicopathological features of gastric carcinoma in southern China and disease trends changes over the last 18 years.

Ramp facies in an intracratonic basin:A case study from the Upper Devonian and Lower Carboniferous in central Hunan,southern China

Detailed studies on Late Devonian to Early Carboniferous carbonate rocks in central Hunan, southern China have led to the recognition of 25 lithofacies which can be grouped into： （I） inner ramp peritidal platform, （2） inner ramp organic hank and mound, （3） mid ramp, （4） outer ramp, and （5） shelf basin facies associations. The peritidal platform facies association dominates the Zimenqiao Formation （Namurian A or late Datangian） and is characterized by gypsum and dolostone-containing sequences, indicating a peritidal platform environment. The other four facies associations dominate the Menggongao Formation （late Famennian）, Liujiatang Formation （Tournaisian or Yangruanian）, Shidengzi Formations （early Visean or early Datangian）. Five upward-shallowing cycles were distinguished in these three Formations. The predominant facies associations developed in each Formation demonstrate an overall transgression-regression cycle in the Late Devonian to Early Carboniferous in central Hunan. The overall transgressive sequence was preserved in the Shaodong, Menggongao, and Liujiatang Formations, and the overall regressive sequence was preserved in the Liujiatang, Shidengzi, Ceshui and Zimenqiao Formations.

Influences of Low-Temperature Hydrothermal Fluids on the Re-distributions and Occurrences of Associated Elements in Coal——A Case Study from the Late Permian Coals in the Zhijin Coalfield, Guizhou Province. Southern China

The occurrences of associated elements and their genetic factors in the No. 30 coal seam in the Zhijin Coalfield were studied using instrumental neutron activation analysis, inductively coupled plasma-atomic emission spectroscopy, and a scanning electron microscope equipped with an energy-dispersive X-ray analyzer. And, a microscope photometer system (Leitz MPV-Ⅲ) was used to observe the characteristics of coal petrology. According to the influence degree by the siliceous low-temperature hydrothermal fluids, the organic matter is divided into four types: A, B, C, and D of the hydrothermally-altered organic matter (HAOM). The study shows that the high content of Fe (2.31%) is not from pyrite, but mostly from the siliceous low-temperature hydrothermal fluids. The occurrences of the associated elements in the four organic matter types are different. The contents of Fe, Si, and Al are decreasing, but S and Cu are increasing in the order of the HAOM-A, HAOM-B, HAOM-C, and HAOM-D. The losing rate of sulfur in organic matter is 0.35% and the content of Fe taken from the low-temperature hydrothermal fluids into the organic matter is 0.794% during the siliceous low-temperature hydrothermal fluids invading the coal seam. The above facts indicate that the low-temperature hydrothermal fluids play a crucial role in the re-distributions and occurrences of associated elements in coal.

An Investigation of the Formation of the Heat Wave in Southern China in Summer 2013 and the Relevant Abnormal Subtropical High Activities

In the summer of 2013, an unprecedented heat wave was experienced over a vast area of southern China. The great areal extent, duration, and strength of this high temperature are very rare. For the 2013 hot spell, the major and direct influence mostly came from the anomaly of the western Pacific subtropical high(WPSH). The abnormally strong and stable WPSH was associated with specific surrounding circulations. The eastward extension of a stronger Qinghai-Xizang high favored the westward extension of the WPSH. The weaker cold air activity from the polar region led to the northward shift of the WPSH and helped it to remain stable. In the tropics, the western segment of the ITCZ was abnormally strong in the period, and supported the maintenance of the WPSH from the south. In addition, the interdecadal variation of the WPSH provided a decadal background for the anomaly variation of the WPSH that summer.

Dengue Fever Epidemiological Status and Relationship with Meteorological Variables in Guangzhou, Southern China, 2007-2012

Ecological methodology plus negative binomial regression were used to identify dengue fever （DF） epidemiological status and its relationship with meteorological variables. From 2007 to 2012, annual incidence rate of DF in Guangzhou was 0.33, 0.11, 0.15, 0.64, 0.45, and 1.34 （per 100 000） respectively, showing an increasing trend. Each 1℃ rise of temperature corresponded to an increase of 10.23% （95% CI 7.68% to 12.83%） in the monthly number of DF cases, whereas l hPa rise of atmospheric pressure corresponded to a decrease in the number of cases by 5.14% （95% CI： 7.10%-3.14%）. Likewise, each one meter per second rise in wind velocity led to an increase by 43.80% or 107.53%, and one percent rise of relative humidity led to an increase by 2.04% or 2.19%.

The First Hadrosaurid Dinosaur from Southern China

A new hadrosaurid dinosaur, Nanningosaurus dashiensis gen. et sp. nov., is described based on an incomplete skeleton from the Late Cretaceous red beds of the Nalong Basin, Guangxi, southern China. Diagnostic features for the new taxon include the presence of a tall and sharply peaked dorsal process of the maxilla with reduced process of the jugal and a distinct lacrimal facet, gracile humerus with low, rounded deltopectoral crest, mandibular condyle of the quadrate transversly broad with reduced paraquadrate notch, dentary tooth with sinuous median carina and subsidiary ridge, relatively few tooth positions, ischial shaft straight along most of its distance, but to curve dorsally and expand at the distal end before the ischial foot begins. Phylogenetic analysis suggests that Nanningosaurus dashiensis is a basal member of Lambeosaurinae.

Methods of Studying Petroleum Systems in Residual Basins-A Case Study of Mesozoic and Palaeozoic MarineBasins in Southern China

Through an integrated study of Mesozoic and Palaeozoic petroleum geology insouthern China and a summing-up of the results of exploration, the authors tentatively put forward aset of methods of studying petroleum systems in modified residual basins or superposed basins. Itscore idea is to put emphasis on the study of the dynamic evolution of petroleum systems. Thetempo-spatial evolution, hydrocarbon-generating processes and hydrocarbon-generating intensities andamounts of resources in different geological stages of chief source rocks are mainly deducedbackward by 3-D basin modelling. The regularities of formation and destruction of oil and gasaccumulations are summarized by analyzing the fossil and existing oil and gas accumulations, thedirection of migration is studied by palaeo-structural analysis, and the dynamic evolution ofPalaeozoic and Mesozoic petroleum systems in southern China is studied according to stages of majortectonic movements. The authors suggest that the realistic exploration targets of Palaeozoic andMesozoic petroleum systems in southern China are secondary and hydrocarbon-regeneration petroleumsystems, while the existing primary petroleum systems are rare. They propose that the favourableareas for exploration of Palaeozoic and Mesozoic petroleum systems in southern China are the frontarea of the Daba Mountains and the steep anticlinal zone on the western side of the Shizhusynclinorium in northeastern Sichuan, the Funin-Yancheng-Hai'an-Xinghua-Baoying area in the northernJiangsu basin, the Qianjiang-Xiantao-Paizhou-Chacan 1 well area in the southern part of the Chenhuarea of the Jianghan basin, the South Poyang basin in Jiangxi and the North subbasin of the Chuxiongbasin. This view has been supported by the discovery of the Zhujiadun gas field in the Yanchengsubbasin of the northern Jiangsu basin and the Kaixiantaixi oil-bearing structure in the southernpart of the Chenhu area of the Jianghan basin.