共查询到20条相似文献，搜索用时 31 毫秒
1.
2.
Total sulfur deposition was determined above a Norway spruce forest, in Hungary. Two methods were applied, on one hand dry + wet deposition measurements and on the other, throughfall and stemflow deposition estimations have been carried out. Results show: total depositions are 3.3 and 3.2 g S m–2 yr–1 determined by dry + wet and throughfall deposition methods, respectively. The share of the dry deposition in the total S-load is 73%. The agreement between the results of the two different methods is good and suggests the needlessness of complicated dry + wet flux measurements, i.e. the total and dry deposition of sulfur compounds to forests can be determined by simple throughfall and wet deposition measurements. 相似文献
3.
本文使用中国科学院常熟和鹰潭生态实验站和气象站的观测资料，应用区域酸沉降模式系统（RegADMS）和大叶阻力相似模型来研究华东地区不同下垫面条件上的大气硫沉降问题，定量估计了农田下垫面上大气硫化物的沉降通量。SO2和硫酸盐的干沉降速率使用大叶阻力相似模型来估计，使用与降水量有关的参数化方案来确定湿沉降系数。结果表明，常熟地区农田下垫面的大气硫沉降通量为19．0gm^-2 a^-1，其中干沉降占42％；而位于江西红壤地区的鹰潭站的大气硫沉降通量为10．4gm^-2a^-1，其中干沉降占83％。比较发现，两地硫干沉降通量绝对值相差不大，但其在总沉降通量中所占的份额有较大差异；常熟站的硫湿沉降通量比鹰潭站要大9．23gm^-2a^-1，该差异是由两地污染状况和气象条件的不同造成。华东地区的年硫沉降总量为1．88Mt（1Mt=10^6t），其中72．8％沉降在农田下垫面上。硫沉降中43％是干沉降，57％是湿沉降。 相似文献
4.
Lei Xiao''en 《Acta Meteorologica Sinica》1996,10(1):118-128
A new dry deposition velocity pattern (NDDVP) for the study of region-scale dry deposition processes is developed. The mean ratio between NDDVP and 1022 experimental data of dry deposition velocity Vd is 1.06±0.82. The result shows that NDDVP is well consistent with experimental data. Practical cases are forecasted by the high resolution regional acid deposition model (EM3) with both NDDVP and old Vd pattern. The maximum ratio between the central concentrations for SO4- can reach 2.4 only due to different Vd patterns. 3-D distributions of species concentrations and dry depositions forecasted by NDDVP are better than those by the old Vd pattern. 相似文献
5.
On the relationship of regional meteorological drought with SOI and NAO over southwest Iran 总被引：2，自引：1，他引：1
Amin K. Dezfuli Mohammad Karamouz Shahab Araghinejad 《Theoretical and Applied Climatology》2010,100(1-2):57-66
A fuzzy hierarchical clustering technique using the pairwise similarity matrix is employed to find the homogenous climate subregions over southwest Iran, based on the similarity of meteorological drought characteristics (i.e., duration, intensity, onset, and ending dates). The representative subregions are recognized for different rainy seasons; for each, the regional rainfall anomalies are computed. To find appropriate drought predictors, the lag relationships of regional rainfall with seasonal Southern Oscillation Index (SOI) and North Atlantic Oscillation (NAO) are examined using a conditional probability approach. The results suggest a significant negative correlation between autumn rainfall and June–August SOI. The NAO is also negatively correlated with autumn rainfall such that it is least likely for an extreme autumn drought to occur when June–August NAO is negative. A spring drought is preceded by an October–December NAO greater than 0.5. However, winter droughts do not appear to be lag-correlated with either SOI or NAO. In addition to the findings for droughts, these indices also emerged having considerable influence on wet seasons. A wet autumn tends to occur when either May–July SOI is less than ?0.5 or June–August NAO is less than about ?0.3. It is also apparent that the extreme wet springs are absent when October–December NAO is positive. This season is influenced most by NAO in both dry and wet spells. However, similar to droughts, the wet winter seasons are not found to be associated with either SOI or NAO. 相似文献
6.
利用贵州省19个测站1951～2000年夏季逐月降水资料,计算了降水量的月平均（区域平均）标准化距平。并进行模糊聚类分析、经验正交函数分解（EOF）和小波分析,研究了贵州夏季降水异常的区域特征。结果表明,贵州夏季降水在近50 a中存在5个明显的气候段：20世纪50年代前期为多雨期;50年代中期到60年代前期为少雨期;60年代中后期为多雨期;70～80年代为少雨期;90年代以后进入多雨期;降水呈增多的趋势。全省一致性是贵州夏季降水的最主要特征,同时还存在区域差异。贵州夏季降水异常有5种空间分布型,即：全省旱（涝）型、东旱（涝）西涝（旱）型、南旱（涝）北涝（旱）型、中东旱（涝）西南涝（旱）型和西南旱（涝）其余涝（旱）型。各型降水具有多时间尺度振荡的特点,存在10～12 a、4～5 a、2～3 a的周期。 相似文献
7.
用区域气候模式 (RegCM_NCC) 对江淮流域地区春季初始土壤湿度异常导致的区域气候效应进行了数值模拟分析, 结果表明:土壤湿度异常变化对区域降水的影响非常显著, 土壤湿度的正异常使得异常区域内降水增大, 地面空气增湿、蒸发加大, 与此相应, 地表气温迅速降低, 土壤湿度的负异常有与之相反的结果, 这种区域气候响应是通过改变地表辐射平衡及地-气系统能通量而实现的; 区域土壤湿度异常对短期气候的影响在一个月之内较明显, 它的影响可持续至以后的几个月, 但强度逐渐减弱; 区域土壤湿度异常的气候响应不仅仅局限于异常区域内部, 而且可以通过次级环流影响到其他区域的降水、温度等变化。 相似文献
8.
9.
采用目前国家干旱监测业务实行的MCI指数,利用Morlet小波、经验正交函数（EOF）等方法,分析了福建省1961—2019年全省66个气象站MCI指数表征的干湿状况和干旱变化特征。结果表明：福建省存在明显的干湿气候特征,具有显著的6—8 a和22 a的周期振荡,内陆山区干湿变化周期比沿海长,在季节尺度上各季均存在多时间尺度和地域差异化的特点;其空间变化具有3种典型模态,反映了季风降水多寡和地形差异。MCI表征的干旱过程时空分布与历史干旱事件相吻合,秋季和冬季是福建省干旱发生频率最高的季节,春季和夏季是干旱强度最强的季节;闽江口以南沿海地区干旱发生率明显高于内陆地区,全省出现同步干旱的机率较小（12%）。 相似文献
10.
Characterization of nutrients in the atmospheric wet and dry deposition observed at the two monitoring sites over Yellow Sea and East China Sea 总被引：5，自引：0，他引：5
To investigate the atmospheric deposition of nutrients into the coastal and shelf regions of the northwest Pacific Ocean,
observation sites were established upon Qianliyan Island (within the Yellow Sea) and the Shengsi Archipelago (within the East
China Sea), respectively. Nutrient concentrations, including , were determined in both aerosols and rainwater samples. The analytical results contain clear seasonal signatures, with high
values during the dry season and low values during the rainy season. Similar trends are observed for deposition fluxes. The
amount of wet deposition is greater than that of dry deposition for the studied nutrient species. The influence of meteorological
factors such as rainfall means that samples from Qianliyan Island record higher nutrient values than those from Shengsi. Along
with riverine inputs, atmospheric deposition plays an important role in determining the biogeochemistry of nutrient species
in coastal and shelf oceans.
An erratum to this article can be found at 相似文献
11.
Measurements of ozone concentrations, and meteorological and surface parameters were carried out over a flat green grassland in northwest Spain, in July 1995. Turbulent parameters and sensible and latent heat fluxes were calculated using the gradient technique. Fluxes and deposition velocity and resistances were evaluated assuming that the diffusivity for heat fluxes was equal to pollutant diffusivity. The daily average value of dry deposition velocity was 6 mm s-1 but it was influenced by wind velocity and atmospheric stability. Resistances have been calculated according to a simple resistance model and a comparison between theoretical and measured values has been made. 相似文献
12.
适用于大中尺度污染物输送模式的粒子干沉降参数化方案 总被引：2，自引：0，他引：2
用“二层”模式给出一个适用于污染物输送模式的粒子干沉降参数化方案,它比较详细地考虑了近地面层的气象条件,地表特性和气溶胶粒子的物理、化学特性等。从计算值与观测值的比较来看,计算值的离散范围能涵盖所有的观测结果,因而从总体上看此参数化方案是合理的,能够描述粒子总污染物干沉降的主要物理过程及机制。
相似文献
13.
利用中尺度非静力MM5模式研究不同初始扰动（误差）对2003年7月4—5日发生在江淮流域的一次梅雨锋暴雨数值预报不确定性的影响,并着重分析了提前36h定量降水的可预报性。结果表明,利用常规观测资料和NCEP/NCAR分析资料形成初始场的控制试验能够提前36h做出较好的模拟。扰动温度场的敏感性试验表明,扰动温度的均方差愈大,降水预报不确定性也愈大。误差演变特征和增长机制分析表明,误差增长具有升尺度特征,误差首先在对流层低层和高层增长,然后大值区向对流层中层扩展;湿降水过程是对流层中低层误差增长的主要机制;对流层高层的误差增长是大气干动力与湿过程共同作用的结果,前期以干过程为主,后期以湿过程为主。 相似文献
14.
Variations of Summer Precipitation and Its Relation with Vapor Transfer over the Qinghai Plateau 
下载免费PDF全文
下载免费PDF全文 From the study of the summer precipitation variation over the Qinghai Plateau and its dependence on vapor transfer, results are presented as follows: 1) during 1961-2003, both the summer rainfall and meridional net vapor flux (NVF) in the atmosphere display a parabola-shaped change with first rise and then drop in intensity and, in contrast, the zonal and regional NVFs exhibit increasing trends; 2) meridional NVF is positively correlated with the rainfall; 3) di erences in vapor transfer throughout atmospheric vertical
extent between dry and wet years over the plateau are shown in that the transfer is stronger in a wet year with large-scale vapor convergence and vice versa in a dry year; in a wet year the meridional vapor transport can reach a belt 3.5 degrees of latitude northward and 7 degrees of longitudes eastward of the positions in a dry year; and vapor flux increases (decreases) by 54.0% (21.9%) in a wet (dry) year with respect to the mean (over 1971-2000). 相似文献
15.
Precipitation chemistry data derived from a sampling network operated in the Inland Sea model region (June 1984–May 1985) are used as a basis for discussing the wet deposition of sulfate on a regional scale in Japan. Horizontal distribution, seasonal variation, relationship between wet deposition and precipitation amount, sulfate/nitrate ratio, and transport of sulfate from the ocean are discussed. Temporal trends in concentrations of atmospheric sulfur compounds and sulfate wet deposition in the model region are also covered. 相似文献
16.
氮氧化物(NOX)在对流层中的收支与循环的研究 总被引：2，自引：0，他引：2
对氮氧化物（NOx）在对流层中的收支与循环问题，及其在对流层中的各种源汇过程进行了综述与讨论。其中包括NOx的人为排放与自然排放，干、湿沉降的清除及其相对重要性等。并对我国NOx的人为排放与自然排放进行了估算。 相似文献
17.
M. A. Tadross W. J. Gutowski Jr B. C. Hewitson C. Jack M. New 《Theoretical and Applied Climatology》2006,86(1-4):63-80
Summary Two cumulus convection and two planetary boundary layer schemes are used to investigate the climate of southern Africa using
the MM5 regional climate model. Both a wet (1988/89) and a dry (1991/92) summer (December–February, DJF) rainfall season are
simulated and the results compared with three different observational sources: Climate Research Unit seasonal data (precipitation,
2 m surface temperature, number of rain days), satellite-derived diurnal precipitation and the Surface Radiation Budget diurnal
short-wave fluxes and optical depth.
Using the ETA model boundary layer in MM5 simulates too much incident short-wave radiation at the surface at 12 UTC, whereas
the medium range forecast model boundary layer yields a diurnal cycle of short-wave radiation closer to the observed. The
Betts-Miller convection scheme in MM5 simulates peak rainfall later in the day and less rain days than observed, whereas when
using the Kain-Fritsch convection scheme a peak rainfall earlier in the day and more rain days than observed are simulated.
The intensity of the hydrological cycle is therefore dependent on the choice of convection scheme, which in turn is further
modified by the boundary layer scheme. Precipitation during the wet 1988/89 season is reasonably captured by most simulations,
though using the Betts-Miller scheme more accurately simulates rainfall during the dry 1991/92 season. Mean DJF biases in
the surface temperature and diurnal temperature range are consistent with biases in the number of rain days and the diurnal
cycles of surface moisture and energy. 相似文献
18.
19.
Abstract The Acid Deposition and Oxidant Model (ADOM) is an Eulerian long‐range transport and deposition model. One of the most highly parametrized and least well established parts of the model is the scavenging module that describes cloud formation, pollutant scavenging, aqueous‐phase chemistry and wet deposition. As a means of gaining insight into the scavenging module, results from simulations with the module are compared with the results from simulations for equivalent conditions with a three‐dimensional dynamic cloud chemistry model. Comparisons of results for a variety of initial conditions show that wet deposition of sulphate, nitrate and ammonium ions tend to be underpredicted by the scavenging module and that the pH of the rain is overpredicted. Although the differences are for the most part not large, they are sensitive to cloud top height. The amount of hydrogen peroxide deposited at the surface is significantly smaller in the ADOM module than in the cloud chemistry model. For the particular conditions that are considered, oxidation is limited by the hydrogen peroxide concentration for the cloud chemistry model, but by the sulphur dioxide concentration for the ADOM module. 相似文献
20.
The Asian Dust Aerosol Model 2 with the MM5 meteorological model has been employed to estimate the dust emission, dust concentration, and wet and dry deposition of dust in the Asian region for the month of March in 2010. It is found that the model simulates quite reasonably the dust (PM10) concentrations both in the dust source region and the downstream region of Korea. The starting and ending times of most dust events and their peak concentration occurrence times are well simulated. The monthly mean maximum surface dust concentration (PM10) is found to be 267???g?m?3 in the domain of central northern China (CNC). Monthly total maximum dust emission of more than 32?t km?2 and that of deposition of more than 25.4?t km?2 (dry deposition of 24?t km?2 and wet deposition of 1.4?t km?2) are found to occur in the domain CNC, whereas the monthly mean minimum surface dust concentration (PM10) is found to be 0.2???g?m?3 in the domain of the Tibetan Plateau, where the monthly total dust emission (4?kg?km?2) and the monthly total dust deposition (9?kg?km?2) are found to be minimum. This monthly total dust deposition of 9?kg?km?2 (dry deposition of 7?kg?km?2 and wet deposition of 2?kg?km?2) is as large as 2.25 times of that of emission (4?kg?km?2), suggesting net dust influx toward the Tibetan Plateau from the surrounding dust source regions. It is also found that the ratio of the total dust deposition to the total dust emission in the source region increases toward the downstream direction from 0.4 in the upstream source region of Taklimakan to 0.80 in the downstream source region of northeastern China. More than 90% of the total dust deposition is found to be contributed by dry deposition due to the lack of precipitation in the dust source region. The monthly mean dust concentration (PM10) is found to decrease with distance away from the dust source region. The monthly mean dust concentration of 62???g?m?3 over the Yellow Sea (YES) decreases to 4.3???g?m?3 over the Northwestern Pacific Ocean (NWP). The monthly total dust deposition in the downstream region is also found to decrease away from the source region from 2.33?t km?2 (dry deposition of 1.36?t km?2 and wet deposition of 0.97?t km?2) over the domain YES to 1.45?t km?2 (dry deposition of 0.16?t km?2 and wet deposition of 1.30?t km?2) over the domain NWP. A large amount of the total dust deposition over the seas is contributed by wet deposition (more than 90%), causing a small decreasing rate of the total dust deposition with distance from the source region. The estimated dust deposition could adversely impact the eco-environmental system significantly in the downstream regions of the Asian dust source region, especially over the seas. 相似文献