An objective classification system of air mass types for Szeged, Hungary, with special interest in air pollution levels

Summary This paper determines the characteristic air mass types over the Carpathian Basin for the winter (December, January, and February) and summer (June, July and August) months dependant on levels of the main air pollutants. Based on the ECMWF data set, daily sea-level pressure fields analysed at 00 UTC were prepared for each air mass type (cluster) in order to relate sea-level pressure patterns with the level of air pollutants in Szeged. The data comprise daily values of twelve meteorological and eight pollutant parameters for the period 1997–2001. Objective definition of the characteristic air mass types is achieved by using the methods of Factor Analysis and Cluster Analysis. According to the results, during the winter months five air mass types (clusters) were detected based on higher concentrations of primary pollutants that occur with high irradiance and low wind speed. This is the case when an anticyclone is found over the Carpathian Basin and over the region south of Hungary, influencing the weather of the country. Low levels of pollutants occur when zonal currents exert influence over Hungary. During the summer months anticyclones and anticyclone ridge situations are found over the Carpathian Basin. (During the prevalence of anticyclone ridge situations, the Carpathian Basin is found at the edge of a high pressure centre.) As a result of high irradiance and very low NO levels, secondary pollutants are highly enriched.     

Isotope geochemistry and Re–Os geochronology of the Yanjiagou Mo deposit in the central North China Craton

The Yanjiagou deposit, located in the central North China Craton (NCC), is a newly found porphyry‐type Mo deposit. The Mo mineralization here is spatially associated with the Mapeng batholith. In this study, we identify four stages of ore formation in this deposit: pyrite phyllic stage (I), quartz–pyrite stage (II), quartz–pyrite–molybdenite stage (III), which is the main mineralization stage, and quartz–carbonate stage (IV). We present sulphur and lead isotope data on pyrite, and rhenium and osmium isotopes of molybdenite from the porphyry deposit and evaluate the timing and origin of ore formation. The δ³⁴S values of the pyrite range from ‐1.1‰ to −0.6‰, with an average of −0.875‰, suggesting origin from a mixture of magmatic/mantle sources and the basement rocks. The Pb isotope compositions of the pyrite show a range of 16.369 to 17.079 for ²⁰⁶Pb/²⁰⁴Pb, 15.201 to 15.355 for ²⁰⁷Pb/²⁰⁴Pb, and 36.696 to 37.380 for ²⁰⁸Pb/²⁰⁴Pb, indicating that the ore‐forming materials were derived from a mixture of lower crust (or basement rocks) and mantle. Rhenium contents in molybdenite samples from the main ore stage are between 74.73 to 254.43 ppm, with an average of 147.9 ppm, indicating a mixed crustal‐mantle source for the metal. Eight molybdenite separates yield model ages ranging from 124.17 to 130.80 Ma and a mean model age of 128.46 Ma. An isochron age of 126.7 ± 1.1 Ma (MSWD = 2.1, initial ¹⁸⁷Os = 0.0032 ± 0.0012 ppb) is computed, which reveals a close link between the Mo mineralization and the magmatism that generated the Mapeng batholith. The age is close to the zircon U–Pb age of ca. 130 Ma from the batholith reported in a recent study. The age is also consistent with the timing of mineralization in the Fuping ore cluster in the central NCC, as well as the peak time of lithosphere thinning and destruction of the NCC. We evaluate the spatio‐temporal distribution of the Mo deposits in the NCC and identify three important molybdenum provinces along the northern and southern margins of the craton formed during three distinct episodes: Middle to Late Triassic (240–220 Ma), Early Jurassic (190–175 Ma), and Late Jurassic to Early Cretaceous (150–125 Ma). The third period is considered to mark the most important metallogenic event, coinciding with the peak of lithosphere thinning and craton destruction in the NCC. Copyright © 2014 John Wiley & Sons, Ltd.     

Unified modeling of flow liquefaction and cyclic mobility

Flow liquefaction and cyclic mobility are two different phenomena that are encountered during strong earthquakes. Flow liquefaction is associated with the contractive behavior of loose granular materials and cyclic mobility is associated with the dilative response of both loose and dense granular materials at low confining stresses. These two types of response pertain to the same material and therefore should be modeled in a consistent manner. Whether a soil in a given state exhibits contractive or dilative behavior is dependent on its dilatancy, d=d_v^p/d_q^p. A form of the dilatancy d=d(η,ψ,C) is proposed, where η=q/p is the stress ratio, and ψ and C denote the internal state variables and the intrinsic properties, respectively. It has been shown that such a state-dependent dilatancy is effective in describing both the contractive and dilative behavior. This allows the soil behavior associated with flow liquefaction and cyclic mobility during earthquakes to be modeled in a unified way.     

大气和植被生态及土壤系统水文过程相互作用的一些研究

利用我国测站的降水资料、卫星测得的OLR和高云量资料、SST和137°E次表层海温资料以及NCEP/NCAR再分析资料,分析了东亚夏季风的爆发和北进的年际变化特征及其与热带西太平洋热状态的关系.分析结果表明:当春季热带西太平洋处于暖状态,菲律宾周围对流活动强,在这种情况下,南海上空对流层下层有气旋性距平环流,西太平洋副热带高压偏东,从而使得南海夏季风爆发早;并且,当夏季热带西太平洋也处于暖状态,菲律宾周围对流活动也很强,在这种情况下,西太平洋副热带高压北进时,在6月中旬和7月初存在明显的突跳,从而使得东亚季风雨带在6月中旬明显由华南北跳到江淮流域,并于7月初由江淮流域北跳到黄河流域、华北和东北地区.这将引起江淮流域和长江中、下游夏季风降水偏少,并往往发生干旱,而黄河流域、华北和东北地区的夏季降水正常或偏多.相反,当春季热带西太平洋处于冷状态,菲律宾周围对流活动弱,在这种情况下,南海上空对流层下层有反气旋性距平环流,西太平洋副热带高压偏西,从而使得南海夏季风爆发晚;并且,当夏季热带西太平洋也处于冷状态,菲律宾周围对流活动也很弱,在这种情况下,西太平洋副热带高压北进时,在6月中旬或7月初向北突跳并不明显,而是以渐进式向北移动,从而使得东亚季风雨带一直维持在长江流域和淮河流域.这将引起此两流域夏季风降水偏多,并往往发生洪涝,而黄河流域、华北和东北地区的夏季降水偏少,发生干旱.作者还从非线性多平衡态动力理论说明了菲律宾周围对流活动强弱对西太平洋副热带高压北进时以突跳或渐进式向北移动起到重要作用.     

RegCM3区域气候模式对中国气候的模拟

使用RegCM3区域气候模式嵌套ERA40再分析资料,对东亚地区进行了15 a（1987-2001年）时间长度的数值积分试验。结果表明：模式可较好地模拟中国地面气温的分布和季节变化,但存在系统性的冷偏差;对降水的变化模拟也较好,但其地理分布模拟存在一定偏差。     

The possible influences of the increasing anthropogenic emissions in India on tropospheric ozone and OH

A 3-D chemical transport model (OSLO CTM2) is used to investigate the influences of the increasing anthropogenic emission in India. The model is capable of reproducing the observational results of the INDOEX experiment and the measurements in summer over India well. The model results show that when NOx and CO emissions in India are doubled, ozone concentration increases, and global average OH decreases a little. Under the effects of the Indian summer monsoon, NOx and CO in India are efficiently transported into the middle and upper troposphere by the upward current and the convective activities so that the NOx, CO, and ozone in the middle and upper troposphere significantly increase with the increasing NOx and CO emissions. These increases extensively influence a part of Asia, Africa, and Europe, and persist from June to September.     

Condensed water in tropical cyclone “Oliver”, 8 February 1993

On February 8, 1993, the NASA DC-8 aircraft profiled from 10,000 to 37,000 feet (3.1–11.3 km) pressure altitude in a stratified section of tropical cyclone “Oliver” over the Coral Sea northeast of Australia. Size, shape and phase of cloud and precipitation particles were measured with a 2-D Greyscale probe. Cloud/ precipitation particles changed from liquid to ice as soon as the freezing level was reached near 17,000 feet (5.2 km) pressure altitude. The cloud was completely glaciated at −5°C. There was no correlation between ice particle habit and ambient temperature. In the liquid phase, the precipitation-cloud drop concentration was 4.0 × 10³ m⁻³, the geometric mean diameter D_g=0.5−0.7 mm, and the liquid water content 0.7−1.9 g m⁻³. The largest particles anywhere in the cloud, dominated by fused dendrites at concentrations similar to that of raindrops (2.5 × 10³ m⁻³) but a higher condensed water content (5.4 g m⁻³ estimated) were found in the mixed phase; condensed water is removed very effectively from the mixed layer due to high settling velocities of the large mixed particles. The highest number concentration (4.9 × 10⁴ m⁻³), smallest size (D_g=0.3−0.4 mm), largest surface area (up to 2.6 × 10² cm² m⁻³ at 0.4−1.0 g m⁻³ of condensate) existed in the ice phase at the coldest temperature (−40°C) at 35,000 feet (10.7 km). Each cloud contained aerosol (haze particles) in addition to cloud particles. The aerosol total surface area exceeded that of the cirrus particles at the coldest temperature. Thus, aerosols must play a significant role in the upscattering of solar radiation. Light extinction (6.2 km⁻¹) and backscatter (0.8 sr⁻¹ km⁻¹) was highest in the coldest portion of the cirrus cloud at the highest altitude.     

Regional and urban population size weights in Saudi Arabia, 1962–1974

The aim of this paper 3s to study the development of population weights for regions and urban centres in Saudi Arabia through the period 1962–1974. In order to achieve this aim some non-parametric statistical rules have been used such as rank-size rule and the four-city index. The results show non-balanced distribution of population on both regional and urban scales. The concentration of people in urban centres is more pronounced than the concentration in regions. This is due to internal and external movement of population towards largesized urban centres. The paper recommends that the official authorities should give more consideration to economic and service development in rural and urban areas that are retreating in ranking and decreasing in population.     

Momentum transport of wave zero during March: A possible predictor for the Indian summer monsoon

Analysis of monthly momentum transport of zonal waves at 850 hPa for the period 1979 to 1993, between ‡S and ‡N for January to April, using zonal (u) and meridional (v) components of wind taken from the ECMWF reanalysis field, shows a positive correlation (.1% level of significance) between the Indian summer monsoon rainfall (June through September) and the momentum transport of wave zero TM(0) over latitudinal belt between 25‡S and 5‡N (LB) during March. Northward (Southward) TM(0) observed in March over LB subsequently leads to a good (drought) monsoon season over India which is found to be true even when the year is marked with the El-Nino event. Similarly a strong westerly zone in the Indian Ocean during March, indicates a good monsoon season for the country, even if the year is marked with El-Nino. The study thus suggests two predictors, TM(0) over LB and the strength of westerly zone in the Indian Ocean during March.     

Grain size and mineralogy of Al Batinah beach sediments,Sultanate of Oman

The nature of Al Batinah coast beach sediments in the Sultanate of Oman was investigated by the analysis of grain size and mineralogy. The beach sediments, mostly light-medium gray green, were predominantly fine sands, with the average grain size of all samples about 200 μm. Some of the particles were gravel (2–16 mm), and some were even larger pebble-size particles (16–256 mm). Some mud (sediment <63 μm) was present, mostly in the sub-tidal sediments. The majority of the samples were skewed to the coarse size with coarse tail partly due to the presence of shell fragments. Approximately 50 % of the beach sediments were quartz with different varieties based on shape and size. The second major component of beach sediment was calcium carbonate which varied from 10 to 65 %. The other components in decreasing order consisted of microbreccia, feldspar, pyroxene, igneous rock fragments, biotite flakes, and heavy minerals. The levels of carbonate were lower in NW Al Batinah coast from Harmul to Al Khaburah but were higher in the SE from Al Khaburah to Al Ghubrah. This could be attributed to either lower carbonate production or more sediment input by wadis along the north-western part of Al Batinah coast. The unique and complex nature of these sediments is largely due to the geology of the terrestrial source area in the Hajar Mountains which contains the famous Samail ophiolite complex and the weak sorting along the shoreline in these tide-modified beaches.