The distribution of acetaldehyde in the lower troposphere during TROPOZ II

A series of 72 measurements of the acetaldehyde (CH₃CHO) mixing ratio were made in the lower troposphere during TROPOZ II. These measurements are the first ever made of the background level of this trace gas in the free troposphere. The data show a vertical decrease of the CH₃CHO mixing ratio with increasing altitude and indicate higher CH₃CHO concentrations in the Northern Hemisphere — in general agreement with a model-derived average CH₃CHO distribution. Deviations of the observed CH₃CHO mixing ratios from the modelled mean distribution are correlated with similar deviations in the corresponding HCHO mixing ratios.     

基于特定因子的河南省干热风客观预报方法

利用2000—2014年5月1日到6月10日河南省121个气象观测站点的逐日观测数据、欧洲中心模式预报资料,对河南省干热风天气进行分析,总结了干热风天气形势分类模型,同时利用多元回归法建立了河南省干热风天气的客观预报方法。分析结果得出:河南省干热风天气发生主要形势为西北气流型、高压脊型和纬向环流型3类;通过多元回归分析筛选出日最高温度预报因子为前一日最高气温、当日最低气温、08:00气温、EC850hPa 24h温度预报,相对湿度预报因子为EC850hPa 24h相对湿度预报、前一日14:00相对湿度、当日08:00露点温度,风速预报因子为EC细网格过去3h10m阵风预报,建立温度、湿度和风速3要素的预报方程;利用预报方程对2014年预报时段的天气进行检验,结果表明,对于轻干热风预报的TS评分为62%,重干热风预报的TS评分为64%。     

SURFACE OZONE CHARACTERISTICS AT THREE STATIONS IN GAW OF WMO IN CHINA

The characteristics of surface O_3 on clear days at Waliguan Observatory,Lin'an regionalstation and Longfengshan regional station in China were analyzed in this paper.The three stationsbelong to Global Atmospheric Watch(GAW)of WMO.There was obvious daily variation on cleardays at Lin'an.with maximum(42.9 ppb)and minimum(20.3 ppb)of daily range appearing inspring and summer.respectively.The daily variation was more regular at Lonfengshan than atLin'an.The maximum(about 27 ppb)appeared in autumn at Longfengshan.There was noobvious daily variation and also daily range was smaller in other seasons except weaker dailyvariation in summer at Waliguan.But the surface O_3 concentration(SOC)in summer was higherthan that in winter at Waliguan.The SOC on clear days of summer at Waliguan was over 20 ppbhigher than at Longfengshan and Lin'an.The global radiation and NO_x concentration were themain factors which control the SOC on clear days at Longfengshan and Lin'an.and playedimportant role in different seasons and areas.The transportation of air flow around the area ofQinghai-Xizang(Tibet)Plateau was the main cause for high SOC and weak daily variation insummer at Waliguan.The similar effect of transportation was obtained at the Mauna LoaObservatory.The distribution characteristics of SOC increasing with height in the tropospheredetermined the difference of SOC between East China and West China.     

SURFACE OZONE CHARACTERISTICS AT THREE STATIONS IN GAW OF WMO IN CHINA*

The characteristics of surface O₃ on clear days at Waliguan Observatory,Lin'an regional station and Longfengshan regional station in China were analyzed in this paper.The three stations belong to Global Atmospheric Watch(GAW)of WMO.There was obvious daily variation on clear days at Lin'an.with maximum(42.9 ppb)and minimum(20.3 ppb)of daily range appearing in spring and summer,respectively.The daily variation was more regular at Lonfengshan than at Lin'an.The maximum(about 27 ppb)appeared in autumn at Longfengshan.There was no obvious daily variation and also daily range was smaller in other seasons except weaker daily variation in summer at Waliguan.But the surface O₃ concentration(SOC)in summer was higher than that in winter at Waliguan.The SOC on clear days of summer at Waliguan was over 20 ppb higher than at Longfengshan and Lin'an.The global radiation and NO_x concentration were the main factors which control the SOC on clear days at Longfengshan and Lin'an.and played important role in different seasons and areas.The transportation of air flow around the area of Qinghai-Xizang(Tibet)Plateau was the main cause for high SOC and weak daily variation in summer at Waliguan.The similar effect of transportation was obtained at the Mauna Loa Observatory.The distribution characteristics of SOC increasing with height in the troposphere determined the difference of SOC between East China and West China.     

桂西两次强降雨过程对比分析

对2005年8月20日和2006年6月13日发生在桂西的两次强降雨并伴有强对流天气过程的影响系统、物理量场和FY-2C红外云图及雷达回波特征进行对比分析。结果表明:造成桂西两次强降雨都是在充足的水汽条件和强烈的上升运动条件下发生的;主要影响系统来自低层切变线、高空低槽和地面静止锋;强降雨过程发生在强烈的不稳定层结区域和K指数高值区。     

桂西两次强降雨过程对比分析

对2005年8月20日和2006年6月13日发生在桂西的两次强降雨并伴有强对流天气过程的影响系统、物理量场和FY-2C红外云图及雷达回波特征进行对比分析。结果表明：造成桂西两次强降雨都是在充足的水汽条件和强烈的上升运动条件下发生的；主要影响系统来自低层切变线、高空低槽和地面静止锋；强降雨过程发生在强烈的不稳定层结区域和K指数高值区。     

广西"02.4.5"强对流天气过程分析

通过对“0 2 .4 .5”强对流天气过程的背景环流、物理量场特征及卫星图像等分析发现 ,在位势高不稳定大气中 ,高空槽过境扰动使不稳定能量发生暴发性释放是这次强对流天气的成因 ;分析还发现卫星图像产品对强对流天气有较好的预示作用     

影响广西的快速台风

统计分析了历年(1949～2001年)影响广西的快速台风的天气气候情况及环流背景,得出此类台风产生、移动的一般规律以及预报思路,为提高此类台风的预报准确率提供有益的参考。     

中国区域空气污染本底站的降水化学特征

分析了3个代表不同背景特征的WMO（世界气象组织）区域本底空气污染站黑龙江五常县龙凤山本底站，北京密云县古北口上甸子本底站和浙江临安本底站的降水化学特征。分析内容为降水的pH值和SO₄2-、NO₃-、Cl-、F-、NH₄+、K+、Na+、Ca2+、Mg2+诸离子的浓度。结果表明，降水pH值和SO₄2-、NO₃-、NH₄+、Ca2+具有年际变化和年变化的特征，但其变化趋势各站及各要素不尽一致。离子Cl-、F-、K+、Na+、Mg2+浓度偏低，变化不明显。就多年平均而言，临安站的pH值为3站最低，SO₄2-为最高。上甸子除了SO₄2-浓度次于临安外，其余所有离子浓度均为3站之首，而且pH值也为3站最高。龙凤山除了降水中的Ca2+、Mg2+离子浓度略高于临安外，其它各离子的浓度是3站中最低，pH值在3站中的位置居中。降水化学特征演变趋势为:3个站的降水皆呈酸性，其中临安最严重，龙凤山其次，上甸子相对轻一些，但其酸化的速率为3站之首。     

广州亚运会期间鼎湖山站大气污染特征

为了解广州亚运会期间华南区域大气质量状况以及气象条件对区域本底浓度值的影响,2010年11月对鼎湖山站主要污染物NO_x,SO₂,O₃,PM₁₀和PM_2.5进行了连续在线观测。利用MICAPS,NCEP FNL资料及后向轨迹模拟对观测时段大气污染物变化特征进行了分析。结果表明:观测时期鼎湖山区域NO₂,SO₂和O₃平均体积分数分别为 (7.2±3.1)×10-9,(8.5±3.8)×10-9和 (28.7±9.8)×10-9。PM₁₀和PM_2.5的月平均质量浓度分别达到113 μg·m-3和81 μg·m-3,PM_2.5超标日数达13 d (标准为世界卫生组织第1阶段值,日平均值为75 μg·m-3)。不同时段日变化分析表明,广州亚运会期间高值时段 (定义为PM_2.5质量浓度超过世界卫生组织的IT.1标准的时段) NO_x和O₃平均体积分数为13.2×10-9和20.9×10-9,较2009年同期分别下降了41.3%和10.7%。不利气象要素影响和污染物区域传输作用是形成珠江三角洲区域大气本底 (鼎湖山地区) 细粒子污染偏高的主要原因。