气溶胶吸收光学特性对低层大气短波加热率的影响   总被引：3，自引：4，他引：3  

苏文颖  陈长和 《高原气象》1997,16(4):353-358

根据气溶胶折射指数的参数化方法确定其虚部ｋ的日变化，并考虑其对短波加热率的影响，发现用ｋ的日平均值代替其逐时值计算大气气溶胶国中热率，将所得结果增大最大增值可达１．６℃／ｄ。  相似文献   

兰州冬季气溶胶的短波加热效应及其对混合层发展的影响   总被引：5，自引：0，他引：5       下载免费PDF全文

田文寿  陈长和 《应用气象学报》1997,8(3):292-301

综合考虑无云天气条件下，气溶胶和大气中各种吸收气体对太阳辐射的影响，建立了一个气溶胶大气的短波加热率模式，研究了兰州冬季气溶胶的短波加热效应。计算结果表明:气溶胶吸收太阳辐射而加热大气的作用是显著的。在上述工作的基础上，建立了一个完全闭合的混合层发展模式，利用数值方法探讨了气溶胶的辐射效应对混合层发展的影响。计算发现大气中气溶胶的增加会抑制混合层的发展，使混合层内的平均位温减小。  相似文献   

Influence of atmospheric inputs on the iron distribution in the subtropical North-East Atlantic Ocean   总被引：3，自引：0，他引：3  

Graldine Sarthou  Alex R. Baker  Jurjen Kramer  Patrick Laan  Agathe Laës  Simon Ussher  Eric P. Achterberg  Hein J.W. de Baar  Klaas R. Timmermans  Stphane Blain 《Marine Chemistry》2007,104(3-4):186-202

Aerosol (soluble and total) iron and water-column dissolved (DFe, < 0.2 μm) and total dissolvable (TDFe, unfiltered) iron concentrations were determined in the Canary Basin and along a transect towards the Strait of Gibraltar, in order to sample across the Saharan dust plume. Cumulative dust deposition fluxes estimated from direct aerosol sampling during our one-month cruise are representative of the estimated deposition fluxes based on near surface water dissolved aluminium concentrations measured on board. Iron inventories in near surface waters combined with flux estimates confirmed the relatively short residence time of DFe in waters influenced by the Saharan dust plume (6–14 months). Enhanced near surface water concentrations of DFe (5.90–6.99 nM) were observed at the Strait of Gibraltar mainly due to inputs from metal-rich rivers. In the Canary Basin and the transect towards Gibraltar, DFe concentrations (0.07–0.76 nM) were typical of concentrations observed in the surface North Atlantic Waters, with the highest concentrations associated with higher atmospheric inputs in the Canary Basin. Depth profiles showed that DFe and TDFe were influenced by atmospheric inputs in this area with an accumulation of aeolian Fe in the surface waters. The sub-surface minimum of both DFe and TDFe suggests that a simple partitioning between dissolved and particulate Fe is not obvious there and that export may occur for both phases. At depths of around 1000–1300 m, both regeneration and Meddies may explain the observed maximum. Our data suggest that, in deep waters, higher particle concentrations likely due to dust storms may increase the scavenging flux and thus decrease DFe concentrations in deep waters.  相似文献   

平流层臭氧对人类活动排放氯化物及氮氧化物的非线性响应          下载免费PDF全文

王革丽  杨培才 《地球物理学报》2007,50(1):51-57

利用本文所建立的平流层下部臭氧异相光化学系统，研究硫酸气溶胶表面积浓度以及氯化物和氮氧化物的排放强度对系统状态的影响.光化系统由19种分别来自氧族、氢族、氮族、氯族和碳族的化学成分组成.研究结果指出，仅就气溶胶而言，它不是一个重要的决定光化系统行为的因子.然而，当它与奇氯ClOx或奇氮NOx的外源共同影响系统时，通过复杂的非线性光化学过程，它将使系统的行为发生重大变化.可以看到，在某些确定的参数范围内，系统存在多平衡态解，并构成一个“折叠"突变流型.  相似文献   

Retrieval of mixing height and dust concentration with lidar ceilometer   总被引：4，自引：2，他引：4  

Christoph Münkel  Noora Eresmaa  Janne Räsänen  Ari Karppinen 《Boundary-Layer Meteorology》2007,124(1):117-128

The Vaisala ceilometers CT25K and CL31 are eye-safe single lens lidar systems reporting attenuated backscatter profiles; they often operate 24 h a day in fully automated, hands-off operation mode. These profiles can be used for more than just cloud-base height determination. In dry weather situations, there is a fairly good correlation between the ceilometer near-range backscatter and in situ PM10 concentration readings. The comparison of mixing height values based on soundings and on ceilometer backscattering profiles indicates that ceilometers are suitable instruments for determining the convective mixing height. Its enhanced optics and electronics enables the CL31 ceilometer to detect fine boundary-layer structures whose counterparts are seen in temperature profiles.  相似文献   

A study of aerosol particle sizes in the atmosphere of Athens, Greece, retrieved from solar spectral measurements     

A.D. Adamopoulos  H.D. Kambezidis  D.G. Kaskaoutis  G. Giavis   《Atmospheric Research》2007,86(3-4):194-206

This work aims at determining the aerosol particle radii in the atmosphere of Athens. Such a work is carried out in Athens for the first time. For this purpose, solar spectral direct-beam irradiance measurements were used in the spectral range 310–575 nm. To estimate the particle radius from aerosol optical depth retrieval, a minimization technique was employed based on the golden-section search of the difference between experimental and theoretical values of the aerosol optical depth. The necessary Mie computations were performed based on the algorithm LVEC.In this study, the mean particle radius of a given distribution was calculated every 30 min during cloudless days in the period November 1996 to September 1997. The largest particles were observed in the summer and the smallest during winter. The result was verified by the increased values of the aerosol optical depth and the turbidity factors calculated in the summer. The differences in the diurnal variation from season to season are attributed to the prevailing wind regime, pollutant emission and sink rates in the atmosphere of Athens.  相似文献   

MODIS遥感中国近海气溶胶光学厚度的检验分析   总被引：16，自引：0，他引：16  

董海鹰  刘毅  管兆勇 《南京气象学院学报》2007,30(3):328-337

基于中分辨率成像光谱仪(TERRA/MODIS)的一级数据和相应的辅助数据,利用MODIS/ARIS预处理软件包(IMAPP)中的气溶胶软件反演得到中国近海气溶胶的光学厚度,与AERONET太阳光度计的反演结果作对比分析,验证了此反演方法的可行性.研究了2002年10-11月中国近海气溶胶光学厚度和Angstrom指数(表征粒子谱宽度)的变化特征,进一步结合气块后向轨迹分析和地理环境背景场信息讨论了卫星反演气溶胶光学参量的适用范围和误差来源,结果表明:IMAPP反演得到的气溶胶光学厚度,在东海和日本以南等广阔海域与气溶胶地基观测网(AERONET)的观测结果基本一致;在渤海和黄海近海岸一带反演值偏高,其主要原因是该海域存在二类水体的影响.  相似文献   

岭南山地气溶胶物理化学特征研究   总被引：16，自引：6，他引：16  

吴兑  邓雪娇  叶燕翔  黄浩辉 《高原气象》2006,25(5):877-885

对岭南山地收集的气溶胶样品的质量谱与水溶性离子成分谱的分析表明:总气溶胶质量与诸离子浓度大体在华南大陆的清洁点均值与大中城市均值之间,其分布主要表现为明显的三峰分布,分别位于巨粒子段,大粒子段与亚微米粒子段,主峰值位于巨粒子段。K 的分布最为特殊,仅仅在细粒子段位于0.065~1.1μm处表现为一个明显的峰。气溶胶中均以SO42-为主要阴离子成分,Ca2 为主要阳离子成分,较之华南乡村清洁对照点,除离子浓度成倍增加外,SO42-浓度占了阴离子含量的绝大部分。另外,NO3-、NH4 的含量比华南城市显著减少是其主要特点。在雨季无论是总浓度还是SO42-、Ca2 、Mg2 的浓度均比旱季时明显减少,与降水的清除过程有关。气溶胶中水溶性NH4 、K 、SO42-较多地存在于细粒态粒子中,它们的质量中值直径在旱季比广州大,在雨季略小于广州的情况;而F-、Ca2 、Cl-、Na 较多地存在于粗粒态粒子中。相对于华南土壤而言,旱季的大瑶山和白云山气溶胶中Mg2 、Ca2 有明显富集,SO42-也有一定程度的富集,雨季仅仅白云山上Mg2 有富集现象。通过离子中和情况的讨论,岭南山地气溶胶应呈酸性,对雨水酸化的缓冲能力较差,会加重该区的酸雨危害。  相似文献   

Atmospheric variability and binary homogeneous nucleation: A parametrisation and conditions required for a significant effect     

J. Lauros  E.D. Nilsson  H. Vehkamki  M. Kulmala 《Atmospheric Research》2006,82(3-4):503

The binary water–sulphuric acid nucleation has long been considered an important path for new particle formation in the atmosphere. The formation rate depends nonlinearly on temperature and vapour concentrations. We aim to find out if atmospheric small scale and mesoscale spatial and temporal variability can increase the nucleation rate significantly. Simultaneous and separate effects of variation in temperature, humidity and sulphuric acid concentration on the mean nucleation rate have been modelled. We have assumed that the distributions of variables are Gaussian and compare the mean of simulated nucleation rates with the nucleation rate in mean conditions without variation. According to our studies the atmospheric variability can increase the mean nucleation rate by orders of magnitude but the significant effect is limited to specific conditions. The effect seems to be more important in the lower troposphere than in the upper troposphere, where temperature and sulphuric acid concentrations are lower. In addition, our model simulations indicate that the atmospheric variability can only explain part of the difference between measured and theoretically required sulphuric acid concentrations in conditions where particle formation has been observed. We have parametrised the effect of atmospheric variability as a simple correction factor for the effect of temperature and humidity variation.  相似文献   

省级MODIS植被指数序列的建立与应用     

张树誉  李登科  李星敏  高蓓 《山西气象》2006,(3):25-28

本文采用安德森分级采样直接获得的大气气溶胶质量密度换算成数密度。在此基础上,根据气溶胶数密度谱分布,验证了大气气溶胶的Junge谱与分段三参数谱相结合的谱模式。并且在得出气溶胶粒子谱基础上计算了大气气溶胶的散射、消光、吸收系数。  相似文献