云中粒子谱形状因子变化对云及降水影响的数值研究

鉴于目前云数值模式和中尺度数值模式中云和降水过程大多用体积水参数化的方式描述,而不同模式所用的粒子谱不同或粒子谱的参数不同,用这些模式模拟研究云和降水的物理过程、降水形成机制、催化防雹和催化增雨机理以及预报降水等就遇到这样一个问题:粒子谱或谱参数不同对研究结果有何影响?因此利用中国科学院大气物理研究所的三维冰雹云催化数值模式,做雹云中粒子谱参数变化的数值试验,分析了冰雹云中雨滴谱、冰晶谱、霰谱的形状参数对降雨降雹、云中微物理过程的影响。结果表明,雨滴谱形状参数变化,对降雨形成机制基本没有影响,对与雨滴有关的物理过程有直接影响。霰谱对地面降雹量、降雹强度、雨强的影响较大,对降雨量影响较小;对冰晶、霰以及冰雹的质量和数量产生率都有明显的影响,云中的所有微物理过程均受到了不同程度的影响,对有些过程影响最为显著,它不但影响粒子的产生过程,也影响粒子的增长过程。冰晶谱对降水量的影响较小,但对各种粒子的某些形成或增长过程影响较大,有的很大。此外,冰晶谱型的变化,对不同地区云或不同个体云降水的影响程度不同,反映了滴谱谱型对云和降水影响的复杂性。利用这些研究结果,讨论了云模式的使用问题。     

一次层状云飞机播云试验的云微物理特征及响应分析

根据2005年3月21日在河南进行的层状云飞机播云试验的探测资料,对人工增雨催化前后层状云的宏微观物理量进行对比分析.结果表明,播云前在4200m高度平飞中观测到的小云粒子数浓度最大值为1.36×108个/m3,相应平均直径在5μm左右;小云粒子数浓度和云液态水含量在催化后均减小,播撒层下方变化较之播撒层变化更加显著;5000m高度小云粒子平均直径由催化前的17.32μm增加到催化后的18.07μm,平均直径明显增大,这些作业前后微观物理量的变化表明了人工催化层状云的物理响应.不同高度飞行具有相似的粒子谱分布.     

云降水物理和人工影响天气研究进展和思考

云降水物理和人工影响天气密不可分,云降水物理为人工影响天气提供理论基础,人工影响天气是云降水物理一个重要应用领域.目前我国人工影响天气规模、经费投入已达世界之最,人工影响天气工程正在建设之中.论文简要回顾了我国云物理研究和人工影响天气的发展过程,评述研究工作取得的进展,思考我国人工影响天气在新形势下进一步的发展的问题,显得尤为重要.几十年来,我国开展了一系列云雾降水的外场观测研究和人工影响天气的外场试验研究,云和降水物理以及人工影响天气的理论和技术研究不断取得进展,数值云模式和中尺度模式的模拟研究水平有了长足的进步,在云和降水物理过程和降水机制研究、云的微物理结构、云水资源和人工增雨潜力评估、催化条件预测、催化剂和催化技术等方面取得了显著进展.论文最后指出,目前的人工影响天气需要加强人工影响天气核心技术研究,并提出了需要进一步研究的云和降水物理中的有关科学问题.     

利用FY-4A卫星反演产品对飞机增雨作业的分析

本文利用FY-4A卫星反演的云降水微物理特征参数,分析了2018年10月8日的一次飞机增雨前层状云的微物理结构和特征参数变化,得到四川盆地秋季层状云增雨潜力区的分布,结果表明:①此次作业过程,四川盆地大部分地区覆盖中低云,局部有高云,中低云含有丰富的过冷水,云底粒子较小10～15μm,主要通过凝结过程增长;②此次作业过程,云系随时间的演变特征为从中午到傍晚,云层加厚,云顶升高,粒子有效半径增长,有大片过冷水区,但是缺乏大滴和冰晶,降水不充分;③在无高云配置下,中低云区产生的地面降水较小,而有高低云共同配置和粒子有效半径较大的地区,降水更为充沛;④利用统计检验中的区域对比分析、双比分析和区域历史回归分析方法对本次飞机增雨进行分析后表明,对具有丰富过冷水区的中低云进行人工引晶后,绝对增雨量分别为1.81mm (对比分析)、1.26mm (双比分析)、1.69mm (区域历史回归分析)。利用FY-4A卫星反演方法能够提供云和降水高时空分辨率的物理特征参数演变,丰富了云和降水宏微观物理信息,为人工增雨判别增雨潜力区和准确把握增雨时机提供了一种新的方法。      

山西省2008—2010年64架次飞机云物理观测结果分析

利用山西省2008—2010年64架次云结构的飞机探测资料,结合地面观测和卫星数据统计分析了层状云系的宏微观特征。结果表明:降水云和非降水云系的微物理特征量,两者存在显著的差异,层状云要达到降水,云的厚度要达到近2000m;粒子尺度分布云粒子有效半径要达到10~14μm,降水性层状云低云含水量垂直方向上平均为0.03g/m3,中云含水量垂直方向上平均为0.05g/m3,;避光高层云-层积云、雨层云降水过冷水的最大值出现在距0℃层高度以上500m附近,其最大值分别为0.61,0.42g/m3;透光高层云降水过冷水的最大值出现在距0℃层高度以上300m附近,其值为0.28g/m3;云中水分按不同粒子尺度的分配可以看出,直径20、30μm的粒子含水量较高,对云中液态水含量的贡献较大,降水粒子主要由20、30μm的粒子转化;降水性层状云在垂直方向上的微物理结构特征非常明显,也是分层的。高层主要是冰相粒子,是冰雪晶,随高度降低冰雪晶的尺度增大,在4个典型温度层的观测中,液态含水量、云粒子及降水的浓度、尺度相较有很大不同。     

华北秋季一次低槽冷锋积层混合云宏微物理特征与催化响应分析

利用2013年10月13日机载粒子测量系统（PMS）在张家口涞源地区对积层混合云中上部进行的增雨探测数据,分析了云的垂直微物理结构、云区的可播性和作业前后液态云粒子、冰晶及降水粒子的微物理变化。结果表明,此次降水性积层混合云的垂直结构由冷、暖两层云配置,云层发展厚实,冷云区云粒子浓度平均为62 cm-3,液态水含量最大0.05 g/m3;2DC和2DP探测的冰晶及降水粒子平均浓度分别为1.9和2.2 L-1;暖云内云粒子数浓度集中在300 cm-3左右,液态水含量约0.1 g/m3。探测区域云粒子数浓度的水平分布不均匀。利用云内过冷水含量和冰晶浓度等参数判断,该降水性积层混合云的播撒作业层具有强可播性。对比作业前后云中粒子浓度及平均直径发现,云粒子在作业前时段内的平均浓度为31 cm-3,远高于作业后平均浓度（17.6 cm-3）;但平均直径变化不大。作业后冰晶粒子通过贝吉龙过程消耗过冷水长大,浓度由之前的0.86 L-1增至4.27 L-1,平均直径也增至550 μm。冰晶粒子逐渐长大形成降水,降水粒子浓度也相应有所升高,谱明显变宽。      

基于飞机真实轨迹的一次层状云催化的增雨效果及其作用机制的模拟研究

层状云降水效率通常较低,但却具有较高的云水资源开发潜力,是人工增雨作业的重要对象。随着中国南方地区生态改善、水库增蓄、抗旱等社会需求的增加,针对这些地区降水云系的人工增雨研究显得愈发重要。使用三维中尺度冷云催化模式,对2018年10月21日湖北省一次层状云飞机人工增雨作业过程进行了数值模拟研究,并将模拟结果与卫星、降水和机载云物理观测数据进行了对比。模式合理地模拟出了云和降水的主要宏、微观特征,观测和模拟结果均显示作业云区具有较好的冷云催化条件,在此基础上,按照实际作业中的飞机播撒轨迹,完整地模拟了此次催化作业过程。对数值模拟结果的分析表明:凝结冻结核化和凝华核化是碘化银催化剂的主要核化方式;90%以上碘化银粒子的局地活化比为0.01%—2%,平均活化比为0.07%—0.27%;云系降水是由冷云降水和暖云降水两种机制共同作用的结果,催化作业使两种降水机制均有增强,增雨效果明显;催化后4 h,整个评估区内的累计净增雨量为2.12×108 kg,局地增雨率为?51.1%—306.7%,区域平均增雨率为8.1%;催化作业也使部分地区出现减雨,主要是由于催化过程中的潜热释放引起过冷层动力场扰动,一部分云区的上升气流减弱,从而导致降水粒子的成长减弱,地面出现减雨;在过冷云区,碘化银核化使冰晶浓度升高,导致冰晶-雪、雪-霰的转化过程增强,雪、霰粒子总量增加,更多的雪、霰粒子从冷区落入暖区,在暖区上层产生更多的大雨滴,从而使暖区的云雨粒子碰并过程增强,最终地面降水增加,这是此次催化作业导致增雨的主要微物理链条。      

典型层状云系催化试验的云物理响应研究

利用2003年秋季延安地区一次典型层状云系加密探空和实时雷达观测资料,设计了催化和对比探测方案,计算得出催化影响区及下风方可能采集到响应值的区域。按照设计方案进行催化和探测。云物理响应观测结果表明:PNS粒子探测系统检测到催化后30min,小云滴减少;大冰晶的浓度增加;催化前冰晶以片状为主,催化后可看到有霰坯;催化前大雪晶浓度很小,雪晶之间没有攀附;催化后雪晶浓度增加,且大雪晶增加很多,可明显看到几个雪团攀附在一起形成的较大雪团;雷达观测到催化前拟播撒区内云的回波强度较弱、范围较小,催化后云体明显增大,强中心增加了5～10dBz;催化约1h后影响区雨量均有增加,说明催化引入的人工冰晶,使冰晶凝结比水滴凝结更有利于过冷云水转化为降水,冰晶效应和雪晶攀附过程是这次层状云系降水系统中的主要过程。过冷水冻结释放的潜热,导致云内升速加大,使催化区云和降水得到发展。     

青海一次春季透雨降水过程的云物理结构分析

2001年5月23日青海省的一次透雨过程基本解决了春旱问题.此次降水预报准确,开展了飞机人工增雨作业,同时利用一架科研探测飞机对降水云层进行较系统的云微物理特征探测.探测结果表明"5·23"透雨过程中,降水云系在降水形成发展阶段有分层现象,上层云云水含量较下层大,云粒子浓度大,水汽主要由较高层的系统输送,由于青藏高原特有的下垫面条件,云系的发展变化较快.云粒子谱分析表明,降水云系生成阶段,云粒子谱不连续,呈间断分布或呈浓度有多峰的特征,降水云系成熟后云粒子谱明显增宽,且浓度增加一个以上数量级.云系的不同发展阶段降水云系的粒子二维特征也有不同.     

"催化-供给"云降水形成机理的数值模拟研究

利用含有详细微物理过程的一维层状云模式模拟,研究了2002年4月5日冷锋降水性层状云云系中"催化-供给"云的微物理结构、降水粒子形成的环节和微物理过程,并从降水形成的环节和云的结构分析人工增雨的条件.结果说明,"催化-供给"云具有显著的分层结构:云内高层是冰晶,下层是雪,接下来是霰和过冷云水组成的冰水混合层,最下方是云中暖区的液水层.作为催化云层的冰水层对降水的贡献约25.5%,冰水混合层为31.3%,液水层为43.1%,亦即供给云对降水的贡献约74.4%.具有"催化-供给"云结构的层状云降水形成的主要环节是:冰晶通过凝华增长转化成雪,雪撞冻过冷云水、收集冰晶和凝华增长转化形成霰,霰靠撞冻过程、收集雪过程长大,从而形成可以降落到云的暖区融化形成雨水的粒子,它对降水的贡献较大.凝华和撞冻增长过程是冰粒子增长的主要物理过程,也是雨水产生的重要过程."催化-供给"云体系是重要的人工增雨条件,云中水汽对雨水形成的贡献与过冷云水几乎相当,与过冷云水一样,水汽也是人工增雨的重要条件.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi region.     

全球贸易隐含碳变化及其影响分析

基于最新的GTAP8 (Global Trade Analysis Project）数据库,使用投入产出法,分析了2004年到2007年全球贸易变化下南北集团贸易隐含碳变化及对全球碳排放的影响。结果显示,随着发展中国家进出口规模扩张,全球贸易隐含碳流向的重心逐渐向发展中国家转移。2004年到2007年,发达国家高端设备制造业和服务业出口以及发展中国家资源、能源密集型行业及中低端制造业出口的趋势加强,该过程的生产转移导致全球碳排放增长4.15亿t,占研究时段全球贸易隐含碳增量的63%。未来发展中国家的出口隐含碳比重还将进一步提高。贸易变化带来的南北集团隐含碳流动变化对全球应对气候变化行动的影响日益突出,发达国家对此负有重要责任。     

Retrieval of outgoing longwave radiation from COMS narrowband infrared imagery

Hourly outgoing longwave radiation(OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite(COMS) has been retrieved since June 2010. The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels. This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm(OLR12.0using the 12.0 μm channel) and three multiple-channel algorithms(OLR10.8+12.0using the 10.8 and 12.0 μm channels; OLR6.7+10.8using the 6.7 and 10.8 μm channels; and OLR All using the 6.7, 10.8, and 12.0 μm channels). The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System(CERES) over the full COMS field of view [roughly(50°S–50°N, 70°–170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5–7 W m-2, which indicates good agreement with CERES OLR over the vast domain. OLR6.7+10.8and OLR All have much smaller errors(～ 6 W m-2) than OLR12.0and OLR10.8+12.0(～ 8 W m-2). Moreover, the small errors of OLR6.7+10.8and OLR All are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration. These results indicate a noteworthy role of the6.7 μm water vapor absorption channel in improving the accuracy of the OLRs. The dependence of the accuracy of COMS OLRs on various surface, atmospheric, and observational conditions is also discussed.     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

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.     

Our Warmest Thanks to AAS Reviewers 2014

正The editorial office of Advances in Atmospheric Sciences(AAS),on behalf of all AAS editors,would like to publicly acknowledge the people listed below who served as reviewers for the journal daring 1 September 2013 to 24 August 2014.We recognize that the time and work of the reviewers is the most important resource in academic publishing.The quality of our journal depends in a crucial way upon the reviewing process and therefore all reviewers'time and efforts taken to sustain the quality of the journal are greatly appreciated.     

Data selection using support vector regression

Geophysical data sets are growing at an ever-increasing rate, requiring computationally efficient data selection(thinning)methods to preserve essential information. Satellites, such as Wind Sat, provide large data sets for assessing the accuracy and computational efficiency of data selection techniques. A new data thinning technique, based on support vector regression(SVR), is developed and tested. To manage large on-line satellite data streams, observations from Wind Sat are formed into subsets by Voronoi tessellation and then each is thinned by SVR(TSVR). Three experiments are performed. The first confirms the viability of TSVR for a relatively small sample, comparing it to several commonly used data thinning methods(random selection, averaging and Barnes filtering), producing a 10% thinning rate(90% data reduction), low mean absolute errors(MAE) and large correlations with the original data. A second experiment, using a larger dataset, shows TSVR retrievals with MAE < 1 m s-1and correlations 0.98. TSVR was an order of magnitude faster than the commonly used thinning methods. A third experiment applies a two-stage pipeline to TSVR, to accommodate online data. The pipeline subsets reconstruct the wind field with the same accuracy as the second experiment, is an order of magnitude faster than the nonpipeline TSVR. Therefore, pipeline TSVR is two orders of magnitude faster than commonly used thinning methods that ingest the entire data set. This study demonstrates that TSVR pipeline thinning is an accurate and computationally efficient alternative to commonly used data selection techniques.     

Temporal vulnerability in hazardscapes: Flood memory-networks and referentiality along the North Carolina Neuse River (USA)

Social models of population vulnerability to disasters increasingly include the notion that vulnerability has a strong temporal component. While this temporality is typically conceptualized as objective (making vulnerability “dynamic,” “multiscalar,” and/or “historical”), it consistently fails to acknowledge that among stakeholders managing hazardscapes temporality is also a social process in which subjective experience of time may play a role in creating situations of population vulnerability. This paper proposes that the temporal situatedness of a population relative to past hazard events and the quality with which stakeholders engage hazard memory-chains combine to significantly influences its vulnerability to natural hazards. It is proposed that this temporal vulnerability is characterized by shared, population level potential for surprise and can be evaluated by exploration of time-series depth and temporal reference points in historical ecological narratives and documents. Based on ethnohistoric research conducted from 2002 to 2006 in flood-prone eastern North Carolina (USA), it is illustrated how temporal vulnerability was relatively higher in the Neuse River watershed located at the City of Kinston than surrounding watersheds. Due to the combination of factors including the damming of the Neuse River in the 1980s, outdated official floodplain maps, relatively unmonitored floodplain development, the stochastic timing of flood events (placing the last major flood more than a generation away), technological optimism, and turnover of floodplain officials and residents, local stakeholders were seriously misinformed about the space-time risks involved both before and after the disaster of Hurricane Floyd (1999) happened. To deal with this inconsistency, the temporal rarity of Hurricane Floyd as a “500-year event” has been motivated and embraced by many in an effort to continue life-as-is. The paper proposes that the concept of temporal vulnerability is further explored and used as key dimension in the vulnerability sciences.     

An assessment of the predictability of the East Asian Subtropical Westerly Jet based on TIGGE data

The predictability of the position, spatial coverage and intensity of the East Asian subtropical westerly jet(EASWJ) in the summers of 2010 to 2012 was examined for ensemble prediction systems(EPSs) from four representative TIGGE centers,including the ECMWF, the NCEP, the CMA, and the JMA. Results showed that each EPS predicted all EASWJ properties well, while the levels of skill of all EPSs declined as the lead time extended. Overall, improvements from the control to the ensemble mean forecasts for predicting the EASWJ were apparent. For the deterministic forecasts of all EPSs, the prediction of the average axis was better than the prediction of the spatial coverage and intensity of the EASWJ. ECMWF performed best, with a lead of approximately 0.5–1 day in predictability over the second-best EPS for all EASWJ properties throughout the forecast range. For probabilistic forecasts, differences in skills among the different EPSs were more evident in the earlier part of the forecast for the EASWJ axis and spatial coverage, while they departed obviously throughout the forecast range for the intensity. ECMWF led JMA by about 0.5–1 day for the EASWJ axis, and by about 1–2 days for the spatial coverage and intensity at almost all lead times. The largest lead of ECMWF over the relatively worse EPSs, such as NCEP and CMA, was approximately 3–4 days for all EASWJ properties. In summary, ECMWF showed the highest level of skill for predicting the EASWJ, followed by JMA.