城市相对湿度的直接模式输出修正预报的研制

给出了一种非统计的直接模式输出（ＤＭＯ）的修正预报方法，它无需任何历史资料（包括数值预报资料及观测资料），仅以我国国家气象中心实时Ｔ１０６模式的离地２ｍ之相对湿度预报格点值（１．１２５°×１．１２５°经纬度）为基础，经非线性插值、部分系统性误差订正及相对湿度的日较差修正后制作全国２６４个城市的相对湿度预报。其中北京、上海、香港等１０个城市的相对湿度预报经预报员把关后，每天晚间由中央电视台播出。     

SSFM方法在中国城市天气预报中的应用

应用英国气象局的特定点预报模式，对2001年6月1日～7月15日中国10个城市的地面温度、相对湿度、海平面气压和风速等气象要素进行平均误差和均方根误差分析检验。结果表明，SSFM方法可用于中国城市天气预报预报业务。     

SSFM方法在中国城市天气预报中的应用

应用英国气象局的特定点预报模式 ,对 2001年6月1日～7月15日中国 10个城市的地面温度、相对湿度、海平面气压和风速等气象要素进行平均误差和均方根误差分析检验。结果表明 ,SSFM方法可用于中国城市天气预报预报业务     

新一代CAPPS系统的开发与推广应用

2002年5月由中国气象局预测减灾司组织,中国气象科学研究院将城市空气质量数值预报系统(CAPPS)第二版发送给全国47个重点城市的气象部门,以取代CAPPS第一版在各城市的空气质量业务预报中应用.与此同时,中国气象科学研究院对47个城市的空气质量预报业务人员进行了培训.CAPPS2以Linux为工作平台在PC机上运行,污染气象预报场由MM5提供,T213资料和常规气象观测资料从MICAPS中获取,可以作48 h的城市污染预报,解决了预报时效问题.CAPPS2还提供各标准等压面上的位势高度、温度、相对湿度、风和降水等气象预报要素场,模式的中心点和网格距可以根据需要随意调整,各省市气象局可以在CAPPS基础上发展适用于本地区的中尺度气象预报、城市污染预报以及其他城市环境气象服务预报模式.     

利用T106资料制作降水概率和相对湿度预报

利用T10 6模式产品 ,采用MOS预报方法 ,建立了甘肃省 15个站降水概率和相对湿度的预报方程。通过相对湿度的绝对误差评分、降水概率的B评分和Bs 评分对预报方程的预报结果进行评估 ,认为预报方程有一定的预报能力。     

冬季高海拔复杂地形下GRAPES Meso要素预报的检验评估

利用GRAPES(Globe/Regional Assimilation and Prediction System)对2010年温哥华奥运会6个场馆气温、相对湿度、风及降水量的预报结果,采用预报准确率、平均误差、平均绝对误差、Alpha Index、TS和ETS评分等统计量对其进行了较详细的评估。结果表明:GRAPESMeso预报相对湿度的准确率最高,且随预报时效的增加,其变化趋于稳定。起初模式对相对湿度的预报偏干,之后逐渐变为预报偏湿;气温预报偏低;风速预报偏大。逐日各要素预报检验结果表明,气温的变化幅度最小;各级降水检验发现,晴雨预报的TS评分最高,且随降水增大,ETS评分逐渐接近TS。与其他模式预报结果对比发现,GRAPES-Meso对复杂地形下要素预报还存在一定的不足。本研究还发现,模式存在一定的系统误差,若能有效订正其误差,将有助于改进模式预报。     

基于模式相对湿度的降水概率预报方法研究

本文采用EC数值模式预报结果与历史观测资料结合的方法,建立了一种基于模式确定性相对湿度预报制作降水概率产品的方法。通过对2012—2013年华东地区EC细网格模式大气相对湿度预报进行分类,将不同层次和不同湿度等级的大气进行分类采样,并统计各类别对应的历史降水概率,分析模式相对湿度与实际降水概率的分布特征,进而根据当前模式预报的相对湿度预报降水概率。采用ETS评分、Brier评分、可信度对比及个例分析方法检验2013年7月至2014年5月降水预报试验效果,结果表明:本文建立基于模式相对湿度的降水概率预报方法可较好的反映未来降水的分布,对天气尺度雨带的预报效果优于对流性降水;与EC模式相比,可有效降低空报现象;与传统集合概率预报相比,本文建立的降水预报方法可更好地反映实际降水的发生概率,降水概率产品能较好的指示降水发生的位置和可能性,具有较好的实际参考价值。     

浙江省温度和相对湿度释用技术及其效果检验分析

基于多模式的要素预报和浙江省乡镇站点观测资料,结合全省天气统计特点,利用最优集成方案,改进了温度和相对湿度的1~7 d预报。统计检验发现,模式的温度预报在浙江省中南部主要表现为系统性偏差,在浙江省北部平原地区主要为随机误差。使用滑动平均误差订正后,浙中南等地形复杂地区温度预报的系统性偏差明显减小。在模式订正基础上,使用动态集成进一步减小了浙北平原地区温度预报的随机误差。基于温湿关系,使用改进后的温度预报对相对湿度预报进行订正。与传统的加权平均方法相比,改进后的温度预报均方根误差减小16.7%,相对湿度预报均方根误差减小13.8%,对改善浙江省精细化预报有一定参考意义。     

利用卫星云图变分同化初始场对热带气旋路径影响的数值试验

利用上海台风研究所的东海热带气旋预报模式，讨论用卫星亮温资料变分同化初始温度场及相对湿度场对热带气旋移动路径的影响。结果表明，对400—925hPa模式层的温度场、相对湿度场和温度场的变分同化对热带气旋移动路径预报有较好的实用意义。     

客观定量预报中降水的预处理

建立预报模型前, 对降水量进行一定的处理会对预报效果有较大的影响。对于降水量为0的样本, 根据对应的相对湿度情况分别赋予0或不同的负值, 并通过神经网络方法, 以中国国家气象中心T213模式、德国气象局业务模式和日本气象厅业务模式相应的降水量预报结果作为预报因子, 利用2003年和2004年夏季资料分别建立了处理后降水量以及未经处理降水量的预报模型。以北京等站为例, 2005年夏季试报结果的对比分析表明:通过相对湿度对降水量进行适当处理后, 预报结果从TS评分、空报率、漏报率及预报偏差来说, 不论是与不进行处理的预报结果还是与模式直接的预报结果相比都有提高, 尤其是减少了空报的情况。该处理方法简单可行, 并且对降水预报效果提高明显。     

CHARACTERISTICS AND TRENDS OF CLIMATIC EXTREMES IN CHINA DURING 1959–2014

The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics.     

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on     

LOW-FREQUENCY CIRCULATION AND EXTENDED-RANGE FORECAST IN CONNECTION WITH AUTUMN EXTREME HEAVY RAINFALL PROCESS IN HAINAN

Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d.     

AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING–TIANJIN–HEBEI REGION UNDER CLIMATE CHANGE

Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms.     

Information for Authors

正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography.     

Information for Authors

AIMS AND SCOPE
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome.     

Information for Authors

AIMS AND SCOPE Atmospheric and Oceanic Science Letters （AOSL） pub- lishes short research letters on all disciplines of the atmos- phere sciences and physical oceanography. Contributions from all over the world are welcome.     

INFORMATION FOR AUTHORS

正Aims Scope Advances in Atmospheric Sciences(AAS)is an international journal on the dynamics,physics,and chemistry of the atmosphere and ocean with papers across the full range of the atmospheric sciences,co-published bimonthly by Science Press and Springer.The journal includes Articles,Note and Correspondence,and Letters.Contributions from all over the world are welcome.