利用850hPa气流资料分析稻飞虱迁飞路径

为了分析我国稻飞虱(褐飞虱Nilaparvata lugens，白背飞虱Sogatella fercifera)迁飞的路径，以确定我国各稻区稻飞虱迁人种群的虫源地，本文在综合各种轨迹分析模型的基础上，提出一种计算稻飞虱迁飞轨迹的实用方法。通过实际虫情与气象资料的验证表明该方法可用于稻飞虱及与稻飞虱迁飞行为相似的中小型迁飞昆虫的轨迹分析及异地预测。     

Acidic Precipitation and Large-Scale Transport of Air Pollutants Observed in Korea

Acid rain at a rural site in Chongwon (KHN), central Korea has been under observation since 1990. To substantiate the 10-year observations, rain samples from six other sites were also collected and analyzed. Results show that acid rain occurred frequently at all sites. At KHN, seasonal and annual variability of pH values had a 10-year VWM value of 4.67 and an arithmetic mean value of 5.09. In general, a high value of pH occurred during springtime when the occurrence of yellow sand (dust) was prevalent in East Asia; during summer, heavy rain usually contained neutral pH values. During other seasons, the degree of acidic precipitation usually coincided with certain air flows. Most frequently, air flows and cyclones coming from south and central China often resulted in precipitation with low pH values observed in Korea. Using daily satellite observations from 1996, we have also been monitoring the long-range and large-scale transport of air pollutants (LSTAP) over East Asia. Many samples of LSTAP were obtained when they were crossing the Yellow Sea and moving over the Korean Peninsula and to SW Japan. The width of the Yellow Sea is ca. 350～700 km and air pollutants take 1～2 days to cross it. Cases of acid rain in Korea clearly correlate wth the LSTAP from source regions in China.     

Mapping of Base Cation Deposition in South Korea

Deposition of non-seasalt base cations (Ca²⁺ + Mg²⁺+ K⁺) in South Korea was mapped for 1994 to 1997 on a 11 × 14 km grid using the so-called inferential modeling technique. It is found that the annual mean wet deposition of non-seasalt base cations is about 290 eq ha^-1 yr^-1 with a maximum of 470 eq ha^-1 yr^-1 and a minimum of 120 eq ha^-1 yr^-1 while the annual mean dry deposition is about 130 eq ha^-1 yr^-1 with a maximum of 240 eq ha^-1 yr^-1 and a minimum 70 eq ha^-1 yr^-1. Theannual mean total deposition of non-seasalt Ca²⁺ + Mg²⁺ + K⁺ is found to be about 420 eq ha^-1 yr^-1 with the predominant range of 400 eq ha^-1 yr^-1 to 550 eq ha^-1 yr^-1 thatoccupies more than 45% of total deposition of non-seasalt base cations and dry deposition constitutes on average30% of the total base cation deposition. About 30% of the annualtotal deposition of sulfur is found counteracted by depositionof non-seasalt base cations over South Korea.     

Rapid Time Variations in Chemical Composition of Precipitation in South Korea

Data from a monitoring program on precipitation at four sites in South Korea during the period from 1993 to 1998 were analyzed for determining a time trend relationship in chemical composition of precipitation. The concentrations of nss-sulphate, ammonium and calcium were found to have decreased over time at a statistically significant level in Seoul (p<0.05). The concentration of nss-sulphate had declined by a rate of 12% per year for the period from 1993 to 1998. The concentrations of ammonium and calcium decreased by 11% and 12% per year respectively for the same period. The concurrent reduction of cation offsets the change in strong acid anion, thus the annual mean pH of precipitation has been approximately constant. In contrast to the rapid change of sulphate, the second most abundant anion, nitrate, showed no statistically significant decrease. As a result, the nitrate to nss-sulphate ratio (N/S ratio) has increased rapidly; the N/S ratio in precipitation has increased from less than 0.1 in 1985 to nearly 0.5 in 1998 at Seoul. In spite of the short monitoring period, a significant upward trend in the N/S ratio was also observed at all of the other sites suggesting that the nitrogen species contribute more to precipitation acidity throughout Korea.     

The Effect of Precipitation Amount and Atmospheric Concentrations on Wet Deposition Fluxes of Oxidized and Reduced Nitrogen Species in Connecticut

The effects of precipitation amount and atmospheric concentrations of inorganic nitrogen species on precipitationconcentrations and wet fluxes of oxidized and reduced nitrogen inConnecticut were studied for a period of 152 weeks (7 February,1997 through 31 December, 1999). The annual volume weighted mean(VWM) concentration in precipitation of oxidized and reducednitrogen varied with precipitation amount between sites andyears. To investigate the effect of varying precipitation amountand mean monthly temperatures on concentrations of inorganicnitrogen species in precipitation, the precipitation events wereclassified into seven groups and each year was divided into twowarm and cold sampling periods. Increasing precipitation amounthad a substantial decreasing effect on the VWM concentration ofnitrate and ammonium ions in precipitation. The highest VWMconcentrations of oxidized and reduced nitrogen in precipitationwere found in the lower weekly precipitation range of 0 to 0.5 cm. The results of this study indicated that precipitationamount was one of the main factors affecting volume weighted meanconcentrations and fluxes of oxidized and reduced nitrogen. Chemical composition of inorganic nitrogen species in theatmosphere showed that during warm and cold sampling periodsreduced nitrogen was the predominant atmospheric specie, andoxidized nitrogen was the predominant wet specie in precipitationat all sampling sites.     

Wet Deposition of Nitrogenous Pollutants and the Effect of Storm Duration and Wind Direction: A Case Study from Inland Southern California

Meteorological factors affecting concentration of dissolved inorganic nitrogen in rain were examined. Rain samples were collected on an event basis from a location 100 km east of the Los Angeles Basin. Analysis of the data demonstrated a double decay function where small increases in rain volume resulted in large decreases in nitrogen concentration. In separate time series collections of individual storms, storm wind direction also influenced nitrogen concentrations     

Relating Tree Ring Chemistry of Pinus densiflora to Precipitation Acidity in an Industrial Area of South Korea

To test the possible use of tree ring chemical properties as proxies for precipitation acidity ([H⁺]), we investigated the relationships between tree ring chemistry (δ¹³C, δ¹⁵N, Ca-to-Al ratio, and N concentration) of Pinus densiflora and precipitation [H⁺] between 1992 and 2005 in an industrial area in the southwest region of South Korea. Statistical analyses showed that all tree ring chemistry parameters were significantly correlated with precipitation [H⁺]. Tree ring δ¹³C was negatively correlated with precipitation acidity (r?=??0.67, P?<?0.01), reflecting the photosynthetic fixation of ¹³C-depleted CO₂ from fossil fuel combustion that would be the primary source of precipitation acidity. A positive correlation of N concentration (r?=?0.89, P?<?0.001) and a negative correlation of δ¹⁵N (r?=??0.63, P?<?0.05) in tree rings with precipitation acidity most likely reflected the influence of ¹⁵N-depleted N compounds deposited via precipitation. The Ca-to-Al ratio was negatively (r?=??0.58, P?<?0.05) correlated with precipitation acidity, indicating that soil acidification caused the loss of Ca from the soil and solubilization of Al resulting from acid precipitation. Such relationships suggest that δ¹³C, δ¹⁵N, N concentration, and Ca-to-Al ratio in tree rings can be reliably used to evaluate the impact of acid precipitation on the studied P. densiflora stands.     

Estimation and Mapping of Nitrogen Uptake by Forest in South Korea

Regional air pollution in northeast Asia is an emerging environmental problem requiring long-term impact assessment of acidic deposition. In this study, the gridded distribution of nitrogen uptake led by both growing forests and harvested biomass for eight tree species: Japanese Larch, Red pine, Korean pine, Oak tree, Chestnut, Other Conifers, Other broad leaved trees, and Mixed forest was identified to estimate critical loads for nitrogen over South Korea. The gridded spatial distribution of averaged nitrogen uptake was mapped by 0.125° Latitude × 0.125° Longitude resolution. The results showed that net uptake of nitrogen led by both growth and harvested biomass was totaled at 438 mol_c ha^?1 year^?1 among which harvested biomass contribution was estimated to be 25 mol_c ha^?1 year^?1, yielding a very small fraction of total nitrogen uptake presumably due to the younger stages of forest in South Korea.     

Evaluation of the Characteristics of Acid Precipitation in Taipei,Taiwan Using Cluster Analysis

This work investigated the characteristics of acid precipitation collected in Taipei, Taiwan during 1991–1995 by performing cluster analysis. The extent to which meteorological conditions influence precipitation chemistry was also elucidated. Three potential sources of water-soluble ions in rainwater were identified: seasalt aerosols (Na⁺, Cl^- and Mg²⁺), anthropogenic pollutants (H⁺ and NO₃ ^-), and mixing sources associated with sulfate (nss-SO₄ ^2-, NH₄ ⁺ and Ca²⁺). As the northeast flow prevailed during the northeast monsoon season, the concentrations of seasalt and sulfate ions in rainwater were significantly high. During that season, a typically high ratio of nss-SO₄ ^2-/NO₃ ^- was also observed, indicating that Taipei might receive foreign pollutants via a long-range transport. In contrast, when the Pacific high dominated the region, nitrate concentration in rainwater was significantly elevated. Also during that period, the ratio of nss-SO₄ ^2-/NO₃ ^- was substantially lower, indicating the prominence of acidic substances contributed by local sources.     

Spatial and Temporal Patterns of Chloride Deposition in Southern Sweden

Monthly bulk deposition of chloride at 49 stations in Southern Sweden between 1989 and 1995 was used to produce quarterly and annual deposition maps through ordinary block kriging. Generally, deposition decreases from the west coast and eastward and displays a large annual variation, governed by the frequency and intensity of midlatitude cyclones. The 1st quarter dominates the temporal pattern all years except 1992. The 4th quarter is the second most important and the 2nd and 3rd quarters have generallylow deposition. The spatial deposition maximum was often displaced from the west coast to the western fringe of the South Swedish highland, due to orographic enhancement of precipitation. On the western rise of the highland, deposition almost entirely co-variates with precipitation. On the west coast and in the eastern part of Southern Sweden, thetemporal pattern is a more complex result of precipitation and frequency of strong westerlies. Comparing the quarterly total dataset with precipitation and frequency of westerly gales shows that both the 3rd and 4th quarters have higher mean precipitation than the 1st quarter, but lower deposition, while the second quarter has substantially lower precipitation but almost equal deposition to the 3rd quarter. The frequency of westerly gales shows a clearer, linear relationship to quarterly deposition. The 1st quarter has the highest variability in deposition and precipitation as well as in frequency of westerly gales. The importance of single highlysalt laden cyclones to the annual deposition is obvious in the 1st quarter of 1993. Changes in cyclone activity due to climate change is therefore of vital importance for the chemical characteristics of the midlatitude atmosphere.     

Temporal Patterns of the Wet Deposition of Zn,Cu, Ni,Cd and Pb: The Arcachon Lagoon (France)

We report here the first data set on wet deposition of heavy metals in the southwestern French coastal zone. In this region, there are two major sensitive coastal ecosystems: the Gironde Estuary and the Arcachon Lagoon. Chemical analyses of heavy metals were carried out by ICP-MS. Annual mean concentrations of the dissolved fraction in precipitation were 0.2, 3.4, 4.3, 8.1 and 30 μg L^-1for Cd, Ni, Cu, Pb and Zn, respectively. In terms of annual fluxes, these numbers are of the same order of magnitude as the fluxes measured in southeastern France, but are higher than those measured in western Brittany. When extrapolated to the entire Bay of Biscay, the annual wet dissolved fluxes of Cd, Ni, Cu, Pb and Zn are respectively 7, 110, 140 340 and 1440 t yr^-1. According to available data in the literature, the regional Cd, Cu, Pb and Zn atmospheric fluxes for the Bay of Biscay are of the same order of magnitude as riverine inputs (Loire and Gironde). On a daily or weekly time scale, we observed a strong variability of elemental fluxes: up to 20% of the annual dissolved flux may occur in a rain event shorter than 3.5 days. Although elements display generally parallel variations with time, they sometimes follow independent behaviours (e.g. Pb and Cd), suggesting that they may derive from different geographical and/or pollution sources.     

An Estimation of the Nitrogen and Phosphorus Loading by Wet Deposition over Lake Maracaibo,Venezuela

In order to make an estimation of thewet deposition levels of the major nitrogen compoundsin Lake Maracaibo system, the precipitation wascollected by events at five sites located on shorearound the Lake from 1991 to 1994. Also the phosphorusconcentrations were determined in rain samples. RainpHs averaged about 5 to 6. NH₄ ⁺ levels weresignificantly higher (up to 1.44 mg L^-1NH₄-N) than NO₃ ^-plus NO₂ ^-ions which resulted in the highest pHs values in thestrait Maracaibo. The strait is the nearest zone toAmmonia Plant located upwind at the TablazoPetrochemical Complex. At the strait, theinorganic-nitrogen ((NH₄ + NO₃ +NO₂)-N) concentrations were greater than organicnitrogen levels, but at the other sites were lower.Phosphorus levels were low, ranging from undetectableto 1.5 mg L^-1; organic-P was estimated to accountfor about 40% of total-P. Total mean nitrogen wetdepositions were 6.93 kg ha^-1 yr^-1 (≈59% asNH₄-N) at the strait and 9.85–16.84 kg ha^-1yr^-1 (≈55% as organic-N) around the lakeshore.Inorganic and organic nitrogen account for about equalportions of the total nitrogen loading. These amountsrepresents ≈24% of the annual total-N inputsby the tributary rivers to the lake and aresubstantially higher than those reported in the shoreof Lake Valencia (north-central part of Venezuela) andother tropical areas. The contribution ofprecipitation to P in lake is very small; ≈0.6 kg ha^-1 of total-P are added annually. The N and Pinputs were greater than the sewage contributions. Themean molar ratio N/P is ≈22 at the straitsite whilst at lake sites the N/P ratio isconsistently >22 (about 35～1 to 100～1). The results of this preliminary study show that the atmosphere represents a significant factor for the total nitrogen loading to Lake Maracaibo system.     

温度耦合驱动下土壤-地下水有机污染物迁移规律与模拟研究进展

场地土壤-地下水有机污染空间分布受场地温度场、水动力场、化学场和生物场等多场控制。明晰有机污染物在土壤-地下水系统中的空间分布规律和驱动机制，定量模拟污染迁移过程，是有效开展污染控制与修复的前提。在众多的影响因素中，温度通过改变有机污染物的理化性质及多相流、化学/生物作用驱动参数，进而影响其在土水介质中的迁移及空间分布。本文综述了有机污染物理化性质（密度、黏度、溶解度）和有机污染化学/生物驱动（挥发、吸附和生物降解）关键参数与温度之间的解析关系，及考虑温度影响的土壤-地下水中有机污染传质过程模拟的研究进展，并针对目前模拟研究的不足提出了耦合温度场的土壤-地下水有机污染物迁移数学模型，为定量探究温度耦合驱动下的有机污染物迁移转化过程和规律提供启示。     

Wet Deposition to an Upland Area of England in 1988 and 1999: Measurements and Modelling

Fine spatial-scale measurements of acidic deposition have been made over two time frames: 1987/1988 and 1999/2000. Over this period, dramatic reductions in precursor emissions have occurred. The two sets of data are compared in order to quantify deposition reductions. Orographic enhancement of wet deposition from the seeder-feeder mechanism is important in the UK at high-elevation sites such as these and the measurements were corrected for this process using a standard methodology. The data were also modelled using a simple long-term Lagrangian acid deposition model and comparisons made with both sets of observations at a resolution of 5 km_5 km. Future scenarios (2010) of emissions were modelled to examine the impact of UK and other European sources in order to determine optimal protection of ecosystems in this region.     

Wet and Dry Deposition Fluxes of Polychlorinated Biphenyls (PCBs) in an Urban Area of Turkey

Atmospheric polychlorinated bihenyls (PCBs) deposit by dry and wet deposition mechanisms, and therefore they constitute a significant polluting source for lands and surface waters. Various samplers have been used to determine the PCB pollution level resulting from deposition. In the presented study, a modified wet deposition sampler (WDS) was used for sampling both wet and dry deposition samples with the same instrument by which wet deposition reservoir of the WDS is opened and dry deposition reservoir is closed when rain starts. Wet and dry deposition samples were collected between June 2008 and June 2009. In the samples taken from BUTAL which is known as an urban area with heavy traffic, ??PCB dry deposition fluxes were determined as 18?±?10 ng/m²??day, and wet deposition fluxes for dissolved and particle phase were measured as 480?±?1,185 and 475?±?1,000 ng/m²??day, respectively. The dissolved and particle-phase PCB concentrations in rain were 10?±?13 and 13?±?14 ng/l, respectively. The contribution of wet deposition to total PCB deposition was determined as 52%. PCB concentrations in the ambient air were measured to be 370?±?200 and 20?±?20 pg/m³ for gas and particle phases, respectively. Washout ratio was determined by proportioning rain concentration to concentration in air. The washout ratios of the samples were between 1,675?C311,800 and 12,775?C2,511,120 for dissolved and particulate phases, respectively.     

Critical Loads of Acid Deposition for Ecosystems in South China — Derived by a New Method

Critical loads of acid deposition for ecosystems in South China are derived by synthesizing the critical loads of acid deposition for soils, the critical loads of SO₂ dry deposition for ecosystems, as well their exceedance. The results show in the southeast of Sichuan province around Chongqing municipality, the central and north of Guizhou province around Guiyang municipality, and the most areas of Jiangsu province, both the critical loads for soils and critical loads of SO₂ dry deposition are exceeded. In Guangxi Zhuang Autonomous Region and some areas among Jiangxi, Zhejiang and Anhui provinces, the critical loads of SO₂ dry deposition is the only restricting factor. There is no area where the critical load for soil is the only restricting factor in South China, so only the critical load for soil is not enough to be the basis to make sulfur abatement scheme.     

Critical Loads of SO2 Dry Deposition and Their Exceedance in South China

The critical loads of SO₂ dry deposition in South China,which is transferred from critical level, as well the excess ofcritical loads are computed and mapped. The areas with thelowest critical load and the highest excess are, respectively,identified. The research is complementary to the previousresearches on critical loads for soils, and expected to beintegrated with them to make efficient sulfur emission abatement strategy.     

Dry and Wet Deposition of Nitrogen Emitted in Buenos Aires City to Waters of de la Plata River

Dry and wet deposition of atmospheric nitrogen species (NO₂ and HNO₃) coming from nitrogen oxides emissions in Buenos Aires city to surface waters of de la Plata River were estimated. Atmospheric dispersion models DAUMOD-RD (v.2) and CALPUFF were applied to area and point sources, respectively. These models were run considering 1 year of hourly meteorological data. Emission information included a typical diurnal variation of area source emissions. Annual atmospheric nitrogen (N–NO₂?+?N–HNO₃) deposition to 1,763 km² of the river was 35,600 kg-N year^?1. Dry deposition processes accounted for 89% of this value. The small contribution of wet deposition was a consequence of the very few cases (5%) of rain events during offshore wind conditions. Monthly dry deposition to 1,763 km² of the river varied from 1,628 kg-N month^?1 in February to 3,799 kg-N month^?1 in December, following the monthly occurrence of offshore winds. Monthly wet deposition varied from 1 kg-N month^?1 in June to 1,162 kg-N month^?1 in February. These results came from the combination of favorable conditions for formation of HNO₃ and the occurrence of precipitation during offshore wind situations. Spatial distribution of annual atmospheric N deposition showed a strong coastal gradient. Deposition values reached a maximum of 137.1 kg-N km^?2 year^?1 near the shoreline, which was reduced to the half at 4 km from the coast.     

广西南部后汛期降水的年际变化及其与低纬度环流系统的遥相关

本文用近４０年（１９５～１９９０年）降水资料，统计出广西南部后汛期降水的年际变化特征，并初步分析了低纬度环流系统对广西南部后汛期降水年际变化的影响。结果表明：（１）广西南部后汛期降水年际变化较大，有明显的准三年变化周期；（２）广西南部后汛期降水的年际变化与同期的副高年际变化有密切联系；（３）广西南部后汛期降水与赤道东太平洋海温及厄尔尼诺现象有明显的遥相关关系。     

华西雨屏区退耕地不同植被经营模式坡面径流和产沙特征分析

利用建立坡面径流观测场,对洪雅县低山区退耕还林中几种植被恢复模式进行定点观测。结果表明:(1)该区域产生坡面地表径流和土壤侵蚀最更本的原因是土地的耕作与否,3年未被直接扰动土壤的退耕地土壤侵蚀量仅是耕地的13.3%～37.9%;(2)林 草、竹 草种植模式的地表径流和土壤侵蚀特征既不同于农耕地,又与未被扰动的生态林植被相差较大。表现为随植被经营利用而出现阶段性的变化,牛鞭草的刈割对退耕地地表径流和土壤侵蚀影响较大。进一步研究、完善林 草、竹 草生态经营技术体系,提高该类退耕种植植被恢复模式的调蓄降雨能力,对指导退耕还林及植被经营有重要的意义。