摘要：氧化镁(MgO)是大气中矿物气溶胶的重要组分之一, 对二次污染物的形成有着重要影响. 本研究采用原位漫反射红外傅里叶变换光谱(DRIFTS)与离子色谱(IC)技术, 研究了二氧化氮(NO2)在MgO颗粒表面的非均相反应. 探讨了无光照、紫外光照、臭氧(O3)、温度及相对湿度(RH)等对该反应的影响机制, 建立了新的测定摄取系数的方法. 结果表明, 无光照时, NO2在MgO颗粒表面生成的主要产物为硝酸盐和亚硝酸盐; 在NO2-MgO-O3和NO2-MgO-hn两种反应体系中主要产物均为硝酸盐, 生成的硝酸根峰面积分别是无光照条件下的1.54倍和3.04倍, O3和紫外光照对硝酸盐的生成均具有促进作用; 在紫外光照条件下, NO2在MgO颗粒物表面生成硝酸根的初始速率随温度的升高而呈单峰变化, 40℃时初始速率最大; 影响NO2与MgO颗粒物反应的敏感因素为紫外光照和臭氧, 其次为相对湿度和温度. 在25℃, RH为5%时, 无光照条件和紫外光照条件下反应初始摄取系数分别为9.01×10-4和5.65×10-3.
韩力慧, 陈媛媛, 贾龙, 程水源, 徐永福,等. NO2在MgO颗粒物表面的非均相反应. 中国科学 化学, 2014, 44(12),2004-2012
Heterogeneous reactions of NO2 on the surface of MgO particles
Abstract：MgO is one of the most important components of mineral aerosol, and it has an important influence on the formation of secondary pollutants. The heterogeneous reaction of NO2 on MgO particles was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC). The influences of no ultraviolet radiation(UV), ultraviolet radiation(UV), ozone (O3), temperature and relative humidity (RH) on the reaction were investigated. A new method has firstly been established to determine uptake coefficients. The main products from the heterogeneous reaction of NO2 on MgO particles were nitrate and nitrite without UV. In NO2-MgO-O3 and NO2-MgO-hv reaction systems, the main product was nitrate, and its infrared adsorption peak areas were 1.54 and 3.04 times higher than that without UV, respectively. O3 and UV were in favor of the formation of nitrate. The initial rate of nitrate, due to the rise of temperature, showed a unimodal pattern with the maximum initial rate at 40℃ under UV. More sensitive factors affecting the reaction of NO2 on MgO particles are UV and ozone, followed by relative humidity and temperature. The initial reactive uptake coefficients of NO2 on MgO particles were determined to be 9.01×10-4 without UV and 5.65×10-3 with UV at 25℃ and 5% RH.
HAN LiHui, CHEN YuanYuan, JIA Long, CHENG ShuiYuan, XU YongFu,et al. Heterogeneous reactions of NO2 on the surface of MgO particles. Scientia Sinica Chimica, 2014, 44(12),2004-2012.
使用全球海洋环流模式LICOM，通过设计三个试验，即以OMIP和WOA09资料为强迫场的试验W，用NCEP/NCAR再分析资料（简称NCEP资料）中的风应力资料代替试验W中的风应力资料的试验M，以及用NCEP资料中的热力强迫代替试验M中的热力强迫资料的试验N，来研究不同的热力和动力强迫场对模式的影响。三个试验的模拟结果均模拟出了水团和流场的分布型和极值区。从三个试验的结果对比可以看出，NCEP资料较弱的风应力使得试验M环流场明显偏弱，减弱了大洋内部的温盐输送，加大了深海温盐模拟结果与观测资料的偏差，但对原模式过强的南极中层水的输送有所改善。NCEP的短波辐射通量和非短波热通量弱于OMIP，且在两极区域NCEP资料的海表温度（SST）比WOA09资料最多低4℃以上。试验N的模拟结果改善了南大洋60°S以南海区试验W 模拟的SST偏高问题，减小了北冰洋部分海域以及副热带大洋东部SST的偏差。此外，试验N高纬度较低的SST增强了北大西洋深水以及南极底层水的输送，因而改善了深海的温盐模拟结果。 三个试验在一些关键海区得到的经向热输送在观测估计及前人模拟结果的范围中，总体上试验M的输送最弱。综合三个试验的模拟结果，可以认为OMIP风应力资料和NCEP SST资料更适合作为LICOM模式的强迫场。
Responses of a Global Ocean Model to Different Forcing Fields
Hu Yaqiong, Liu Haiwen,Li Yangchun,Xu Yongfu
With a global ocean general circulation model, the influences of different thermal and dynamical forcing fields on the model simulation are studied by designing three different numerical experiments, including the run called Exp W with the forcing from OMIP and WOA09, the run called Exp M in which the wind stress in Exp W is replaced with NCEP/NCAR reanalysis data, and the run called Exp N in which the thermal forcing in Exp M is further replaced with NCEP/NCAR data. These simulations were performed with the LASG/IAP climate system ocean model named LICOM. Three numerical experiments all generate the observed features of distributions of water mass and large-scale circulation. A comparison analysis of these three experiments shows that because of weak wind stress in NCEP data, the simulated circulation fields are weaker in Exp M than those in Exp W, including that the transport strength of the Antarctic Circumpolar Current in Exp M is 13% weaker than that in Exp W, and that the strengths of two overturning cells on both sides of the equator and the Deacon Cell are reduced in Exp M, which reduces the transport of temperature and salinity in Exp M, leading to the increase in the differences of temperature and salinity between simulations and observations in the deep water. Because both short-wave radiation fluxes and other non-short-wave thermal fluxes are smaller in NCEP data than those in OMIP data, and the SST in the two polar regions in NCEP data is up to over 4°C smaller than that in WOA09 data, the simulated results from Exp N improve the results with higher SST in the region south of 60°S obtained by Exp W, and reduce the deviation of SST in some areas of the Arctic Ocean and eastern subtropical region obtained in other experiments. In addition, lower SST in the higher region in Exp N enhances the transport of North Atlantic Deep Water and Antarctic Bottom Water, so that the simulated temperature and salinity in the deep water are improved. The meridional heat transport in the critical areas obtained by three experiments generally lies within the uncertainty range obtained with data-based estimate and by other researchers. The meridional heat and volume transports in Exp. M are weakest during these three experiments. Based on the synthesis of three simulation results, it can be considered that the wind stresses of OMIP are more suitable for LICOM than NCEP data.
Citation:Liu Haiwen,Li Yangchun,Xu Yongfu.2015.Responses of a Global Ocean Model to Different Forcing Fields[J].Chinese Journal of Atmospheric Sciences (in Chinese)