内蒙古草原温室气体排放日变化规律研究

采用静态值－气相色谱法研究内蒙古草原温室气体N2O、CO2、CH4与大气交换的日变化规律。CO2日排放变化形式基本相同，和大气交换的总结果是向大气排放，影响草原N2O排放日变化形式的关键是土壤含水量和表层土壤理化特性，日温变化主要影响其日变化强度；影响草原CH4日变化形式的关键因子是土壤水分和供氧状况，而温度和植物的生长状况则影响吸收强度，利用内蒙古草原温室气候排放相对固定的日变化形式，可以对相同生产季内每周1次的观测结果进行矫正。     

城市蓝天指数预报研究

1引言随着中国经济的迅速发展和城市化进程的不断加快,人类活动对自然环境造成巨大的影响,而日益恶化的自然环境也在进一步威胁着人类的生存[1]。近几年雾和霾频发,蓝天越来越稀少,百姓对蓝天的关注度越来越高,蓝天指数预报正是在这样的背景下提出来的,它是根据气象条件的一个综合表述。     

那曲站与其相邻野外站气象要素的对比分析

利用1955-2009年西藏那曲气象站(NQ站)和2001-2009年BJ野外气象站(BJ站)的观测资料,对NQ站和BJ站气温、风速的变化特征进行了对比分析。结果表明,BJ站的年平均温度和最低温度均低于NQ站,年平均风速反之;两站(NQ站-BJ站)温度差的增长率依次为最低温度(0.117℃.a-1)>年平均温度(0.034℃.a-1)>最高温度(-0.014℃.a-1),年平均风速为0.076m.s-1.a-1;以青藏铁路正式通车的2006年为界,2001-2005年和2006-2009年分别为人类活动影响较弱期和较强期。人类活动影响较强期与较弱期相比,两站温度差异增加的幅度依次为最低温度(0.512℃)>年平均温度(0.152℃)>最高温度(-0.025℃),年平均风速为-0.198m.s-1。     

哈尔滨市非职业性一氧化碳中毒潜势预报方法浅探

本文分析了天气形势和气象条件对非职业性一氧化碳中毒的影响,得出了地面高压控制、气温低、相对湿度大、风速小、逆温强、混合层厚度小的天气条件下一氧化碳污染潜势预报等级高的气象特点,从而为非职业性一氧化碳中毒潜势预报提供了较为实用的理论依据。     

椭球雨滴群旋转轴呈正态分布情况时雷达反射率因子的修正

推导出了在云降水粒子群为小旋转椭球水滴群、椭球旋转轴呈正态分布、云降水粒子谱为M-P分布情况下的雷达气象方程,并且重新定义了相应的雷达反射率因子,确定了在用雷达测定非球形雨滴降水时的订正系数。为新一代多普勒天气雷达观测资料的雨滴形状和分布特征订正、提高降水测量精度提供了理论依据和方法。     

Size Distributions and Elemental Compositions of Particulate Matter on Clear, Hazy and Foggy days in Beijing, China

Total suspended particulates(TSP)samples were collected using low pressure impactors(Andersen Series 20-800,USA)on typical clear,hazy and foggy days in Beijing in order to investigate the characteristics of size distributions and elemental compositions of particulate matter(PM)in different weather conditions. The concentrations of sixteen elements,including Na,Mg,Al,K,Ca,Mn,Fe,Ni,Cu,Zn,As,Se,Cd,Ba,Tl and Pb were detected using inductively coupled plasma mass spectrometry(ICP-MS).The results showed that Ca,Al,Fe,Mg and Ba on foggy days were 2.0-2.6 times higher than on clear days,and 2.3-2.9 times higher than on hazy days.Concentrations of Cu,Zn,As,Se and Pb on foggy days were 163.5,1186.7,65.9,32.0 and 708.2 ng m-3,respectively,in fine particles,and 68.1,289.5,19.8,1.6 and 103.8 ng m-3,respectively,in coarse particles.This was 1.0-8.4 times higher and 1.4-7.4 times higher than on clear and hazy days,respectively.It is then shown that Mg,Al,Fe,Ca and Ba were mainly associated with coarse particles,peaking at 4.7-5.8μm;that Cd,Se,Zn,As,Tl and Pb were most dominant in fine particles,peaking at 0.43-1.1μm;and that Na,K,Ni,Cu and Mn had a multi-mode distribution,with peaks at 0.43-1.1μm and 4.7-5.8μm.The enrichment factors indicated that coal combustion along with vehicle and industry emissions may be the main sources of pollution elements.     

A Comparison of De-noising Methods for Differential Phase Shift and Associated Rainfall Estimation

Measured differential phase shift ΦDP is known to be a noisy unstable polarimetric radar variable, such that the quality of ΦDP data has direct impact on specific differential phase shift KDP estimation, and subsequently, the KDP-based rainfall estimation. Over the past decades, many ΦDP de-noising methods have been developed; however, the de-noising effects in these methods and their impact on KDP-based rainfall estimation lack comprehensive comparative analysis. In this study, simulated noisy ΦDP data were generated and de-noised by using several methods such as finite-impulse response(FIR), Kalman, wavelet,traditional mean, and median filters. The biases were compared between KDP from simulated and observedΦDP radial profiles after de-noising by these methods. The results suggest that the complicated FIR, Kalman,and wavelet methods have a better de-noising effect than the traditional methods. After ΦDP was de-noised,the accuracy of the KDP-based rainfall estimation increased significantly based on the analysis of three actual rainfall events. The improvement in estimation was more obvious when KDP was estimated with ΦDP de-noised by Kalman, FIR, and wavelet methods when the average rainfall was heavier than 5 mm h-1.However, the improved estimation was not significant when the precipitation intensity further increased to a rainfall rate beyond 10 mm h-1. The performance of wavelet analysis was found to be the most stable of these filters.     

边界层湍流输送的若干问题和大气线性热力学

总结了大气线性热力学基本理论,讨论了大气边界层的能量和物质输送交叉耦合效应,还讨论了大气系统动力过程和热力过程的交叉耦合效应。分析指出：由于动力过程和热力过程的交叉耦合效应,导致大气边界层能量和物质输送过程除了湍流输送外,还应包括大气辐散和辐合运动对能量和物质的输送。非均匀下垫面大气边界层和对流边界层辐散和辐合运动对能量和物质输送是重要的。在这个基础上,讨论了非均匀下垫面和对流边界层地表能量的平衡问题,非均匀下垫面和对流边界层陆面过程边界层参数化等问题。这些研究不仅丰富了大气边界层物理理论,而且为克服当前大气边界层物理应用中所遇到的困难提供了理论依据。     

关于位涡理论及其应用的几点看法

位涡理论能非常有效地解释天然现象,预测天然系统的变化,合理应用该理论的关键是对其原本思路和原理有非常透彻的理解,本文试图对此谈几点看法。     

CoLM模式对青藏高原中部BJ站陆面过程的数值模拟

利用公共陆面模式Common Land Model(CoLM)及"全球协调加强观测计划之亚澳季风青藏高原试验"(CAMP/Tibet)中那曲地区Bujiao(BJ)站2002—2004年的观测资料对该地区进行了单点数值模拟试验。通过比较模拟与观测的地表能量通量,表明CoLM较成功地模拟了该地区的能量分配。模式对向上的短波辐射、向上的长波辐射、净辐射及土壤热通量模拟得较好,但冬季存在偏差。进一步比较了模拟和观测的土壤温度及土壤湿度,发现浅层60 cm土壤温度模拟较好,深层存在偏差,表现为土壤温度变化滞后于实际变化。土壤湿度总体偏小,尤其是冬季冻结期,土壤冻融过程中忽略了土壤液态水在温度0℃以下仍能存在,含冰量模拟偏高。