Characteristics of Hg pollution in urban stormwater runoff in Nanjing city, China

In order to assess the mercury Hg pollution in urban stormwater runoff in Nanjing 11 rainfall events in the Maqun region of Nanjing circle expressway were monitored and the events mean concentrations EMC of Hg and the impact of rainfall characteristics on Hg pollution in runoff were analyzed.Results show that the pollution of different Hg species is serious and total Hg THg dissolved Hg HgD and particulate Hg HgP are found to be in the range of 0.173 to 3.347 0.069 to 0.862 and 0.104 to 2.485μg/L respectively.The average EMC value of THg exceeds the Ⅴ class limitation value of Quality standards of surface water environment GB 3838-2002 of China. Hg in runoff mainly exists in particulate form and the concentrations of Hgre 0.250 to 2.821 μg/L are far more than those of Hg0 0.023 to 0.215 μg/L and Hg2＋ 0.026 to 0.359 μg/L . The order of rainfall characteristics impacting on Hg pollution in runoff is dry periods 〉runoff time〉duration of rainfall〉storm intensity〉rainfall.

Framework Design of Emergency Public Warning Information Release Platform in Hunan Province

Construction background of Hunan emergency public warning information release platform was introduced,and current status and demands of provincial information release were analyzed.Supported by GIS,Java,and Net,Hunan early warning information release platform of public emergency was constructed based on ORACLE database and Windows 2008 Server,achieving information collection,packaging,transmission,de-packaging,and releasing concentration,standard and processing.In addition,the framework and functional characters of the system were illustrated and the innovation points were explored.The system provides guarantee for meteorological services and disaster prevention or reducing of Hunan public emergencies.

ENSO cycle and climate anomaly in China

The inter-annual variability of the tropical Pacific Subsurface Ocean Temperature Anomaly （SOTA） and the associated anomalous atmospheric circulation over the Asian North Pacific during the E1 Nifio-Southern Oscillation （ENSO） were investigated using National Centers for Environmental Prediction/ National Center for Atmospheric Research （NCEP/NCAR） atmospheric reanalysis data and simple ocean data simulation （SODA）. The relationship between the ENSO and the climate of China was revealed. The main results indicated the following： 1） there are two ENSO modes acting on the subsurface tropical Pacific. The first mode is related to the mature phase of ENSO, which mainly appears during winter. The second mode is associated with a transition stage of the ENSO developing or decaying, which mainly occurs during summer; 2） during the mature phase of E1Nifio, the meridionality of the atmosphere in the mid-high latitude increases, the Aleutian low and high pressure ridge over Lake Baikal strengthens, northerly winds prevail in northern China, and precipitation in northern China decreases significantly. The ridge of the Ural High strengthens during the decaying phase of E1 Nifio, as atmospheric circulation is sustained during winter, and the northerly wind anomaly appears in northern China during summer. Due to the ascending branch of the Walker circulation over the western Pacific, the western Pacific Subtropical High becomes weaker, and south-southeasterly winds prevail over southern China. As a result, less rainfall occurs over northern China and more rainfall over the Changjiang River basin and the southwestern and eastern region of Inner Mongolia. The flood disaster that occurred south of Changjiang River can be attributed to this. The La Nifm event causes an opposite, but weaker effect; 3） the ENSO cycle can influence climate anomalies within China via zonal and meridional heat transport. This is known as the ＂atmospheric-bridge＂, where the energy anomaly within the tropical Pacific transfers to the mid-high latitude in the northern Pacific through Hadley cells and Rossby waves, and to the western Pacific-eastern Indian Ocean through Walker circulation. This research also discusses the special air-sea boundary processes during the ENSO events in the tropical Pacific, and indicates that the influence of the subsurface water of the tropical Pacific on the atmospheric circulation may be realized through the sea surface temperature anomalies of the mixed water, which contact the atmosphere and transfer the anomalous heat and moisture to the atmosphere directly. Moreover, the reason for the heavy flood within the Changjiang River during the summer of 1998 is reviewed in this paper.

Comparative Study between Waffle and Solid Slab Systems in Terms of Economy and Seismic Performance of a Typical 14-Story RC Building

In order to maximize the return of investments and at the same time improve the quality in the construction industry of midrise buildings, it is very important to derive an optimal solution to the building structural system, which would facilitate faster and easier construction activities with minimal quantity of construction material, while maintaining the satisfactory level of building safety and performance. This paper makes a comparative study between a ＂solid＂ and a ＂waffle＂ slab system. A typical 14-story RC building structure is selected as an example for this study purpose. The first part of this study is focused in deriving an optimal solution for a solid and waffle slab system which are later on considered as constituents of all stories of the 14-story building. In the second part, it is elaborated the effect of both slab systems over the 14-story building model. This study aims to emphasize the advantages of mid-rise buildings constituted of waffle slab system over the buildings characterized with solid types of slabs, in terms of economy, structural safety and performance.

STUDY OF A COMPREHENSIVE MONITORING INDEX FOR TWO TYPES OF ENSO EVENTS

Some recent studies presented two existing types of ENSO events, one is the Eastern-Pacific(EP) type and the other the Central-Pacific(CP) type. This study examined the monitoring ability of several current operational ENSO indices. The results indicated that a single index could not distinguish the EP and CP in the historical ENSO events during 1950-2009. The Nio 3 index may only be suitable for monitoring the EP-type ENSO, while the Nio 4 index works only for the CP-type ENSO. In order to capture the occurrence of ENSO events and distinguish the type, we considered a new monitoring index group using Nio 3 and Nio 4 indices. Further analysis confirmed that this index group can monitor different types of historical ENSO events with different spatial distribution of sea surface temperature. It has a good performance in determining the characteristics of the ENSO events, including peak intensity, onset,decay, and mature phase.

A New Approach for Classifying Two Types of El Nio Events

In recent decades, the typical E1 Nifio events with the warmest SSTs in the tropical eastern Pacific have become less common, and a different of E1 Nifio with the wannest SSTs in the central the east and west by cooler Pacific, which is flanked on SSTs, has become more frequent. The more recent type of E1 Nifio was referred to as central Pacific E1 Nifio, warm pool E1 Nifio, or dateline E1 Nifio, or the E1 Nifio Modoki. Central Pacific E1 Nifio links to a different tropical-to-extratropical teleconnection and exerts different impacts on climate, and several clas- sification approaches have been proposed. In this study, a new classification approach is proposed, which is based on the linear combination （sum or difference） of the two leading Empirical Orthogonal Functions （EOFs） of tropi- cal Pacific Ocean sea surface temperature anomaly （SSTA）, and the typical E1 Nifio index （TENI） and the central E1 Nifio index （CENI） are able to be derived by projecting the observed SSTA onto these combinations. This classification not only reflects the characteristics of non-orthogonality between the two types of events but also yields one period peaking at approximate two to seven years. In particular, this classification can distin- guish the different impacts of the two types of events on rainfall in the following summer in East China. The typi- cal E1 Nifio events tend to induce intensified rainfall in the Yangtze River valley, whereas the central Pacific El Nifio tends to induce intensified rainfall in the Huaihe River valley. Thus, the present approach may be appropriate for studying the impact of different types of E1 Nifio on the East Asian climate.

Heat center of the western Pacific warm pool

A heat center （HC） of the western Pacific warm pool （WPWP） is defined, its variability is examined, and a possible mechanism is discussed. Analysis and calculation of a temperature dataset from 1945-2006 show that the mean position of the HC during this period was near 0.4°S/169.0°E, at 38.0 m depth. From a time series of the HC, remarkable seasonal variability was found, mainly in the meridional and vertical directions. Interannual variabilities were dominant in the zonal and vertical directions. In addition, semiannual variation in the HC depth was discovered. The longitude of the HC varies with ENSO events, and its latitude is weakly related to ENSO on time scales shorter than a decade. The variation of the HC longitude leads the Nifio-3 index by about 3-4 months, and its depth lags the index for approximately 3 months. It is concluded that the HC depth results from a combination of its longitudinal and latitudinal variations. Low-pass-filtered time series reveal that the HC has moved eastward since the mid 1980s.

Water discharge variability of Changjiang(Yangtze) and Huanghe(Yellow) Rivers and its response to climatic changes

Influences of large-scale climatic phenomena, such as the E1Nifio/La Nifia-Southem Oscillation （ENSO） and the Pacific Decadal Oscillation （PDO）, on the temporal variations of the annual water discharge at the Lijin station in the Huanghe （Yellow） River and at the Datong station in the Changjiang （Yangtze） River were examined. Using the empirical mode decomposition-maximum entropy spectral analysis （EMD- MESA） method, the 2- to 3-year, 8- to 14-year, and 23-year cyclical variations of the annual water discharge at the two stations were discovered. Based on the analysis results, the hydrological time series on the inter- annual to interdecadal scales were constructed. The results indicate that from 1950 to 2011, a significant downward trend occurred in the natural annual water discharge in Huanghe River. However, the changes in water discharge in Changjiang River basin exhibited a slightly upward trend. It indicated that the changes in the river discharge in the Huanghe basin were driven primarily by precipitation. Other factors, such as the precipitation over the Changjiang River tributaries, ice melt and evaporation contributed much more to the increase in the Changjiang River basin. Especially, the impacts of the inter-annual and inter-decadal climate oscillations such as ENSO and PDO could change the long-term patterns of precipitation over the basins of the two major rivers. Generally, low amounts of basin-wide precipitation on interannual to interdecadal scales over the two rivers corresponded to most of the warm ENSO events and the warm phases of the PDO, and vice versa. The positive phases of the PDO and ENSO could lead to reduced precipitation and consequently affect the long-term scale water discharges at the two rivers.

The extreme dry/wet events in northern China during recent 100 years

Using monthly precipitation and monthly mean temperature, a surface humid index was proposed. According to the index, the distributed characteristics of extreme dryness has been fully analyzed. The results indicated that there is an obvious increasing trend of extreme dryness in the central part of northern China and northeastern China in the last 10 years, which shows a high frequency period of extreme dryness; while a low frequency period in the regions during the last 100 years. Compared with variation trend of the temperature in these regions, the region of high frequent extreme dryness is consistent with the warming trend in the same region.

Reinforcement selection for deep and high-stress tunnels at preliminary design stages using ground demand and support capacity approach

Underground mining is going to be deeper gradually because near surface resources are going to be depleted. Therefore, risk of seismic events in underground mines is escalating. Additionally, existence of the large ratio of horizontal to vertical stress, could be a potential reason for high-stress condition and occurrence of dynamic activities. Depending on various parameters such as the level of induced stress, rock properties, etc., ground demand changes and it is difficult to estimate. On the other hand,under seismic condition, energy dissipation and deformation capacity of supports is the most important factors, however, rock support performance factors in dynamic conditions are still under investigation.Expanding the knowledge of reinforcement behaviour and capacity, specifically that of the rockbolt as a primary element in seismic conditions, would help to develop a suitable, safe and economic support design. This paper contains various methods to estimate ground demand including the intact rock properties approach, failure thickness and ejection velocity estimation, and rockburst damage potential method. It also covers measurement methods of rockbolts energy dissipation capacities such as drop test,blasting simulating, back calculation and momentum transfer measurement methods. A large-scale dynamic test rig is also explained. Based on the findings, a table and a graph to show the applicable range of each type of rockbolts were presented. Suitable rockbolt types for various ground energy demand and deformation capacity range were categorised in the table and the graph. The presented support selection method facilitates the selection of a suitable reinforcement system at the preliminary stages of design and guides the designer to adjust the support reinforcement system based on observed ground and support reaction.

Distinguished Effects of Interannual Salinity Variability on the Development of the Central-Pacific El Ni o Events

El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming context.Various physical processes have been identified in the climate system that can be responsible for the modulation of El Nio,especially the effects of interannual salinity variability.In this work,a comprehensive data analysis is performed to illustrate the effects of interannual salinity variability using surface and subsurface salinity fields from the Met Office ENSEMBLES (EN3) quality controlled ocean dataset.It is demonstrated that during the developing phase of an El Nio event,a negative sea surface salinity (SSS) anomaly in the western-central basin acts to freshen the mixed layer (ML),decrease oceanic density in the upper ocean,and stabilize the upper layers.These related oceanic processes tend to reduce the vertical mixing and entrainment of subsurface water at the base of the ML,which further enhances the warm sea surface temperature (SST) anomalies associated with the El Nio event.However,the effects of interannually variable salinity are much more significant during the CP-El Nio than during the eastern Pacific (EP) El Nio,indicating that the salinity effect might be an important contributor to the development of CP-El Nio events.

The Influence of Two Kinds of El Ni?o Events on the Strong Tropical Cyclone Generation and Strength in the Pacific Ocean

This paper focuses on the effects of two types of El Nino events on tropical cyclone activity. We classified El Nino events from 1961 to 2015 according to their sea surface temperature （SST） anomalies into an eastern type and a central type. Then we selected strong tropical cyclones to statistically analyze the tropical cyclone characteristics during different events and their effects, as well as to study the possible mechanisms related to thermodynamic and dynamic factors. The tropical cyclone generation areas were found to be very similar during the two kinds of events. The average number of tropical cyclone in the eastern event is more than that in central event, and the hurricane in northeastern Pacific （HNP） has more energy than the typhoon in northwestern Pacific （TNP） in all cases. The seasonal distribution of the TNP high-incidence centers during central El Nifio events is opposite to that of the HNP. The TNP accumulated cyclone energy （ACE） intensity is similar in the fall and summer, and the HNP ACE intensity in the summer is greater than that in the fall. The SSTs are consistent with the TNP and HNP movement trends. The Walker circulation intensity was strongly affected by the eastern events, but it quickly returned to its normal state, while the intensity was slightly reduced in the central events, and it slowly returned to its normal state. The vertical velocity distributions in the Pacific are different at different stages of both events, and the distributions of vertical velocity anomalies for typhoons and hurricanes are consistent.

Evolved Urban Form to Respond to Extreme Sea Level Events in Coastal Cities

Along with climate change and global warming, ESLEs （extreme sea level events） are seriously threatening coastal cities＇ development. In order to respond to such events, transformational adaptation strategy in urban planning might play an important role. For instance, it has been proposed that BCR （building coverage ratio） should be minimized to a certain range in order to enhance coastal areas＇ resiliency. For the purpose of urban planning practices, the main objective of this research is to develop a method which could formulate the proper BCR range in vulnerable coastal areas. The research is conducted through simulating storm surge floods in simplified waterfront settlements with different BCRs. Data representing the impact of ESLEs collected through CFD （computational fluid dynamic） simulations has been examined. This research has proved that in dense coastal areas, ESLEs may cause serious damage to the built environment if their protective structures fail. It showed that controlling BCR is an effective way to enhance their resiliency. When the BCR is low, the pressure caused by storm surge floods and wave height can be greatly reduced. However, decreased BCR may also reduce land utilization efficiency. Simulation results indicated that controlling the BCR to around 36% might be the most effective scenario which balances resiliency and land use efficiency. They also showed that under the same storm surge flood scenario, the pressures caused by flood waves could be reduced if the length of the building is increased. This study might be considered as transformational adaptation measures that contributes some knowledge for waterfront development in vulnerable locations, and it also provides scientific and useful proof for sustainable strategies in coastal cities and reveals that particular urban design tools, such as BCR control, could play an essential role in responding to ESLEs.

Sub seasonal variations of weak stratospheric polar vortex in December and its impact on Eurasian air temperature

Weak stratospheric polar vortex(WPV)events during winter months were investigated.WPV events were identified as being weakest in December,accompanied by the most dramatic increase in geopotential height over the polar region.After the onset of a December WPV event,the dynamic processes influencing Eurasian temperature can be split into two separate periods.Period I(lag of 0-25 days)is referred to as the stratosphere-troposphere interactions period,as it is mainly characterized by stratospheric signals propagating downwards.In Period I,a stratospheric negative Northern Annular Mode(NAM)pattern associated with the WPV propagates downwards,inducing a negative NAM in the troposphere.The anomalous low centers over the Mediterranean and North Pacific bring cold advection to northern Eurasia,resulting in a north-cold-south-warm dipole pattern over Eurasia.The zero line between negative and positive temperature anomalies moves southwards during days 5-20.Stratospheric cold anomalies at midlatitudes propagate downwards to high latitudes in the troposphere and contribute to the dipole structure.During PeriodⅡ(lag of 25-40 days),as downward signals from the stratosphere have vanished,the dynamic processes mainly take place within the troposphere.Specifically,a wave train is initiated from the North Atlantic region to northern Europe.The propagation of wave activity flux intensifies a cyclonic anomaly over northern Europe,which brings cold advection to Scandinavia and warm advection to central Asia.Therefore,a northwest-cold-southeast-warm dipole structure occupies Eurasia and migrates southeastwards during this period.

The Influence of El Ni?o on MJO over the Equatorial Pacific

In this paper, the influence of E1 Nino event on the Madden-Julian Oscillation （MJO） over the equatorial Pacific is stud- ied by using reanalysis data and relevant numerical simulation results. It is clearly shown that E1 Nino can reduce the intensity of MJO. The kinetic energy of MJO over the equatorial Pacific is stronger before the occurrence of the E1 Nino event, but it is reduced rapidly after E1 v event outbreak, and the weakened MJO even can continue to the next summer. The convection over the cen- tral-western Pacific is weakened in E1 Nino winter. The positive anomalous OLR over the central-western Pacific has opposite variation in E1 Nino winter comparing to the non-ENSO cases. The vertical structure of MJO also affected by E1 Nino event, so the opposite direction features of the geopotential height and the zonal wind in upper and lower level troposphere for the MJO are not remarkable in the E1 Nino winter and tend to be barotropic features. El Nino event also has an influence on the eastward propa- gation of the MJO too. During E1 Nino winter, the eastward propagation of the MJO is not so regular and unanimous and there exists some eastward propagation, which is faster than that in non-ENSO case. Dynamic analyses suggest that positive SSTA （El Nino case） affects the atmospheric thickness over the equatorial Pacific and then the excited atmospheric wave-CISK mode is weakened, so that the intensity of MJO is reduced; the combining of the barotropic unstable mode in the atmosphere excited by external forcing （SSTA） and the original MJO may be an important reason for the MJO vertical structure tending to be barotropic during the E1 Nino.

Comparative Analysis of Extreme High Temperature Weather in the Summers of 2013 and 2003

The characteristics of regional high temperature(HT) weather in 2013 and 2003 and their causes were studied using daily maximum temperature data, National Center for Environmental Prediction(NCEP) reanalysis data, and outgoing longwave radiation(OLR) data. For these two years of HT weather, there were many similar characteristics, such as their long duration, wide range, high intensity, and severe influence. However, there were also three obvious differences: firstly, in 2013, the major area where HT weather occurred was farther north than in 2003; secondly, the HT weather in South China and the southeast area of Jiangnan in 2013 lasted fewer days than in 2003, but in other areas it lasted for more days than in 2003; thirdly, the intensity of the HT weather in 2013 was also stronger in the north and weaker in the south, similar to that of the duration. A strong and stable western Pacific subtropical high(WPSH), a continental warm high, and the distribution of the warm center in the lower troposphere played important roles in the HT weather formation. Several probable causes for the differences are that the cold air was weaker, the WPSH was farther north, and the tropical convective systems were stronger in 2013 than in 2003. Finally, a preliminary cause analysis of the WPSH anomaly was presented.

Subsurface temperature anomalies in the North Pacific Ocean associated with the ENSO cycle

Multi-year Simple Ocean Data Assimilation （SODA） and National Centers for Environmental Prediction （NCEP） datasets were used to investigate the leading patterns of subsurface ocean temperature anomalies （SOTA） and the corresponding atmospheric circulation structure in the Pacific Ocean （20°S-60°N）. In this paper, the evolution of North Pacific SOTA associated with El Nifio-southern oscillation （ENSO）, and their relationship with the overlying zonal/meridional atmospheric circulations were elucidated. The results indicate that： （1） there are two dominant modes for the interannual variability of the North Pacific SOTA. The primary mode is the dipole pattern of the central and western North Pacific SOTA associated with the leading mode of ENSO, and the second mode is the zonal pattern related to the second mode of ENSO. These two modes consist of the temporal-spatial variation of the SOTA in the North Pacific. （2） During the developing phase of the El Nifio event, positive （negative） SOTA appears in the western （central） portion of the North Pacific Ocean. During the mature and decaying phase of the E1 Nifio event, the western positive center and the central negative center continue to be maintained and enhanced. Meanwhile, the position of the western positive center slightly changes, and the central negative center moves eastward slowly. After the El Nifio event vanishes, the positive SOTA disappears, and the central negative SOTA becomes weak and remains in the northeastern Pacific Ocean. The results for La Nifia are generally the opposite. （3） During the El Nifio/La Nifia cycle, formation and evolution of the SOTA, with opposite signs in central and western North Pacific Ocean, resulted from vertical movement of the two northern branches of the Hadley Cell with opposite direction, as well as the positive feedback of the air-sea interaction induced by dynamic processes in the mid-latitudes. The former gives rise to the initial SOTA, and the latter intensifies SOTA. Under the forcing of these two processes, SOTA evolution is formed and sustained during the El Nino/La Nina events. Also discussed herein as background for the ENSO cycle are the possible connections among the West Pacific subtropical high, the strength of the Kuroshio near the East China Sea, the Kuroshio meanders south of Japan, the Aleutian Low, and cold advection in the central North Pacific Ocean.

Coral Reef Recovery Status in South Andaman Islands after the Bleaching Event 2010

The Andaman and Nicobar Islands are one of the Union Territories of India, located in the eastern part of the Bay of Bengal. In 2010 summer, the increment in sea surface water temperature （up to 34℃） resulted in the bleaching of about 74% to 77% of corals in the South Andaman. During this event, coral species such as Acropora cerealis, A. humilis, Montipora sp., Favia paIlida, Diploastrea sp., Goniopora sp. Fungia concinna, Gardineroseries sp., Porites sp., Favites abdita and Lobophyllia robusta were severely affected. This study is to assess the recovery status of the reef ecosystem by estimating the percentage of Live Coral cover, Bleached coral cover, Dead coral with algae, Rubble, Sandy fiat, Algal assemblage and other associated organisms, The sedimentation rate （mg cm^-2 d^-1） and coral coverage （%） were assessed during this study period. The average sedimentation rate was ranged between 0.27 and 0.89 mg cm^-2 d^1. The observed post bleaching recovery of coral cover was 21.1% at Port Blair Bay and 13.29% at Havelock Island. The mortality rate of coral cover due to this bleaching was estimated as 2.05% at Port Blair Bay and 9.82% at Havelock Island. Once the sea water temperature resumed back to the normal condition, most of the corals were found recovered.

Research on the Relationship of ENSO and the Frequency of Extreme Precipitation Events in China

Based on a daily precipitation observation dataset of 743 stations in China from 1951 2004, the F distribution function is used to calculate the probability distribution of daily precipitation and to define extreme precipitation events. Based on this, the relationship of ENSO and the frequency of extreme precipitation events is studied. Results reveal that ENSO events have impact on extreme precipitation events, with different magnitudes at different regions and seasons. In general, during winter and spring, extreme precipitation events occur more often during E1 Nino events than during La Nina events. While during summer and autumn, the opposite is found. The relationship of a two season-lag ENSO and extreme precipitation frequency shows different pattern. Extreme precipitation events occur more often in several regions if an ENSO warm phase happened in the central-eastern tropical Pacific two seasons before. No similar impacts of El Nino and La Nina on the frequency of extreme precipitation events are found.

Studies on Marine Oil Spills and Their Ecological Damage

The sources of marine oil spills are mainly from accidents of marine oil tankers or freighters, marine oil-drilling platforms, marine oil pipelines, marine oilfields, terrestrial pollution, oil-bearing atmosphere, and offshore oil production equipment. It is concluded upon analysis that there are two main reasons for marine oil spills: (I) The motive for huge economic benefits of oil industry owners and oil shipping agents far surpasses their sense of ecological risks. (II) Marine ecological safety has not become the main concern of national security. Oil spills are disasters because humans spare no efforts to get economic benefits from oil. The present paper draws another conclusion that marine ecological damage caused by oil spills can be roughly divided into two categories: damage to marine resource value (direct value) and damage to marine ecosystem service value (indirect value). Marine oil spills cause damage to marine biological, fishery, seawater, tourism and mineral resources to various extents, which contributes to the lower quality and value of marine resources.