层状云微物理属性垂直分布的季节变化——以新疆地区为例

利用CloudSat卫星资料2B-CLDCLASS和2B-CWC-RVOD数据集,分别揭示了层云与层积云的云粒子等效半径、数浓度及含水量等微物理属性的垂直分布特征及其季节变化规律。结果表明：层云所在的云层高度比层积云高,特别是春季,层云可以延伸到11.0 km处,而层积云云层所在高度最高出现在夏季,最高延伸到8.5 km处。层云中的冰水分布在1.0~11.0 km,液态水分布在0~9.0 km,而层积云的冰水和液态水均分布在0~9.0 km。层云与层积云的冰粒子等效半径、水云粒子数浓度、液态水含量呈现随云层高度的增加而减小的趋势,冰粒子数浓度随云层高度增加呈增大趋势,冰水含量呈峰值分布,峰值出现在6~10 km范围内。各季节层积云粒子等效半径、粒子数浓度及水含量的最大值均大于层云的对应值,从这方面看,层积云更适合作人工增水对象。     

基于卫星资料的气溶胶对冰云影响及分布特征分析

通过利用2010年1月—2016年12月CALIOP(the Cloud-aerosol lidar with orthogonal polariz-ation)冰云和气溶胶3级月平均产品和MODIS(Moderate-resolution imaging spectroradiometer)大气3级日平均产品研究气溶...     

京津冀夏季强降水下冰云宏微观特征

根据Aqua MODIS 2级云产品和Cloudsat的2级产品资料,结合降水数据和MODIS L1B级辐射率数据,对发生在京津冀地区夏季的三次强降水过程中冰云的宏微观物理量的特征进行分析,并探究这些物理量和降水强度的关系。结果表明：在水平分布中,强降水过程中降水强度高值区内云相为冰云,冰云云顶高度在8~17 km,冰云粒子有效半径、冰云光学厚度、冰水路径分别最高可达60 μm、 150、 5 000 g?m^-2;冰云光学厚度、冰水路径、冰云云顶高度随降水强度增大而增大。在垂直分布中,冰云主要分布在3.5 km以上,发生强降水站点的冰云为深对流云,冰云粒子有效半径、冰水含量、冰云粒子数浓度分别最高可达150 μm、 3 000 mg?m^-3 、 500 L^-1;冰云粒子有效半径高值区存在于云层中下部,且随高度上升而减小,冰云粒子数浓度高值区存在于云层中上部,且随高度上升而增加,冰水含量高值区则存在于云层中部;冰云粒子有效半径、冰水含量、冰云粒子数浓度在9 km以上随降水强度增大而增大。     

Case study on microphysical properties of boundary layer mixed-phase cloud observed at Ny-Ålesund,Svalbard: Observed cloud microphysics and calculated optical properties on 9 June 2011

Cloud radiation interactions are important in the global climate system. However, an understanding of mixed-phase boundary layer clouds in the Arctic remains poor. During May–June 2011, ground-based in situ measurements were made at Zeppelin Station, operated by the Norwegian Polar Institute (altitude 474 m) in Ny-Ålesund (78.9°N, 11.9°E), Svalbard. The instruments used comprised a Cloud, Aerosol and Precipitation Spectrometer (CAPS), and a Cloud Particle Microscope imager. The CAPS incorporated a Cloud and Aerosol Spectrometer and Cloud Imaging Probe (CIP). During the observation period, clouds associated with cyclonic disturbances and those associated with outbreaks of westerly cold air masses from the sea were observed. Atmospheric temperature during all measurements ranged from 0 to −5 °C. In every case, columns were the major type of ice particle measured by the CAPS–CIP. Cloud microphysical properties were observed continuously on 9 June 2011. Size spectra, liquid/ice water content, and particle effective size changed depending on progress stages. Based on the observed microphysics, optical properties were calculated and investigated. Optical properties were determined mainly by those of liquid water particles, even during periods when the relative contribution of ice particles to total water content was at the maximum. It was confirmed that the wavelength region of 1.6 and 2.2 μm can be used in remote sensing. This study shows that it is possible to measure detailed changes of cloud properties in the Arctic region by using instruments installed at a ground-based mountain station.     

基于CERES的宁夏空中云水资源特征及其增雨潜力研究

利用2009-2014年NASA地球观测系统(EOS)云与地球辐射能量系统(CERES)云资料和气象站降水资料,对宁夏北部引黄灌区、中部干旱带及南部山区3个具有不同地形、地貌、气候特征的地区云水资源及增雨潜力特征进行了对比研究。结果表明:宁夏地区大气可降水量在空间分布上呈现从东南向西北方向递减,从季节变化看表现出随夏秋春冬依次递减的特征。在东亚季风和贺兰山地形的共同影响下,全年总云量和低云量在南部山区最大,北部川区最小。云光学厚度与水云粒子半径及冰云等效直径呈显著的负相关关系,其中中部干旱带相关关系最强是开展人工增雨效果最显著的地区。随着全年四季天气气候变化,宁夏人工增雨主要潜力区会逐渐由春季的贺兰山沿山、中部干旱带地区,移动到夏季的银川以南同心以北和固原西南部地区,秋季缩减到海原、西吉一带。     

FY-2C资料进行云顶粒子热力学相态分析应用初探

利用"9210"系统下发的FY-2C图像资料数字化信息,依据高云、中云、低云在可见光波段和红外波段具有不同的光谱特性,结合水汽通道和红外通道对密蔽云系的辐射特性,分析了2008年华南低温雨雪冰冻期间红外、水汽、可见光3个通道云系的辐射特征,发现了有利于识别水云、冰云和冰水混合云的方法。同时指出,对于密蔽云系,当水汽亮温值大于0℃而红外亮温值小于0℃时,云顶粒子的热力学相态为过冷却液态水的可能性大于冰晶结构的可能性。根据上述辐射特性分析制定了云类的识别方法。实例分析结果表明这种方法能较好地分离出易产生冻雨的云体中缺少成冰核的过冷却液态水云。     

西北干旱半干旱区一次层状云系微物理特征分析

利用西北干旱半干旱区一次飞机探测资料、卫星资料,分析了层状云微物理结构以及作业前后云微物理变化,结果表明：（1） 此次层状云系垂直结构配置为冷暖两层,云层发展厚实。云的垂直和水平分布极不均匀。相对层积云,高层云小云粒子浓度低,大云粒子浓度高,液态含水量高。小云粒子浓度尤其是峰值区域与平均直径呈明显反相关。大于60个·cm^-3和35个·L^-1的小云、大云粒子浓度分别主要由3.5~10 μm、50~200 μm粒径段决定。（2） 不同高度云粒子谱为单峰或双峰分布,总体呈单调递减趋势,但云形成和增长条件存在差异。强可播、不可播和可播性冷云粒子谱基本符合负幂指数的单调递减规律,云粒子浓度差异较大,自然冰晶浓度不可播云较高,可播云次之,强可播云较低。（3） 作业后小云粒子浓度明显降低,在6.5~20 μm粒径段降低了2个量级左右,大云粒子浓度明显增加,谱宽增大,尤其在大于150 μm粒径段。     

南极海冰问题评述:观测

海冰通过其对地面反照率的作用以及对大气和海洋之间热交换的局地障碍和对世界海洋环流的作用在全球热平衡和气候变化中起着重要的作用。南极海冰又因其极为显著的时空变化引起越来越多的关注。海冰的观测是海冰研究的重要内容 ,本文综述了南极海冰观测的发展过程 ,着重介绍了卫星在探测南极海冰方面的重要进展 .     

基于 MODIS 和 CloudSat 的京津冀降水冰云季节分布特征

利用 2008 年 9 月~2016 年 8 月 Aqua MODIS 和 CloudSat 卫星数据,筛选出京津冀地区的降水 冰云,同时将其分为 4 个区域讨论,得到关于该地区降水冰云 4 个季节的分布特征,为该地区的人 工影响天气提供依据。结果表明：京津冀整个地区的降水冰云在夏季的发生率都较高,且发生率 有上升的趋势。从整个地区看来,京津冀地区的降水冰云的云顶高度在冬季最低、夏季最高,云顶 温度的最小值在冬季最高、夏季最低;京津冀地区的降水冰云在春夏秋 3 季均以单层云为主,而在 冬季则以双层云为主;京津冀地区的降水冰云的类型按春夏秋冬分别为 7 种、7 种、6 种和 5 种,且在 夏季该地区的降水冰云以深对流云为主（占 48.3%）,而其他季节以雨层云为主;京津冀地区降水冰 云微物理量（包括冰水含量、粒子数浓度、粒子有效半径）主要分布高度分别为 0~13.5 km（春季）、 3.5~17.0 km（夏季）、1.0~14.0 km（秋季）、0~11.0 km（冬季）。冰水含量、粒子有效半径和粒子数浓度 的分布高度和最大值均在夏季最高,但粒子有效半径在秋季最低,冰水含量和粒子数浓度在冬季 最低。这 3 种微物理量随高度的分布特征夏季在京津冀各分区较为一致,都呈单峰结构,在其他季 节差异较大。     

中天山山区大气总水汽量和云液水量的遥感研究

使用QFW-1型双通道微波辐射计,于2002年盛夏(7月10日至8月5日)在天山山区乌鲁木齐河流域上风方的小渠子进行了大气积分水汽和云中积分液水量的遥感观测。观测表明;中天山山区盛夏的晴天平均大气水汽含量与目前公认的亚洲大气中的水汽含量相近;晴天的平均大气水汽量具有明显的日变化。对降水云系的液态水含量及其变化遥感监测表明:云系降水具有先兆性;不同类型降水性云的降水临界值不同;云液水由0.5 mm开始上升到降水临界值的降水酝酿期的时间,可以作为天山山区人工增雨实施播云作业的重要参照指标。     

北冰洋浮冰区的气象要素特征

利用中国首次北极科学考察队观测的气象资料 ,初步分析研究了 1 999年 8月 1 9～ 2 4日北冰洋浮冰 ( 75°N,1 60°W)上的温、压、湿、风、云量、辐射、海表温度、冰面及冰中温度等气象要素变化特征 ,并结合 50 0 h Pa高度场分析了该期间的天气过程。结果表明 :在考察期间海面与冰面温度日变化差异明显。除晴天夜间出现逆温外 ,气温随高度增大而减小 ,冰面为热源 ,不断有向上的热量输送。海温则稳定少变。冰中热交换主要发生在冰下 0～ 40 cm深度。由于有海上湿平流等影响 ,存在“逆湿”现象。晴天反射率具有明显日变化 ,早晚大 ,中午小。海冰表面平均反射率约为 0 .76。辐射与云量特别是低云量的关系密切     

Detecting Arctic snow and ice cover with FY-1D global data

Chinese meteorological satellite FY-1D can obtain global data from four spectral channels which include visible channel(0.58-0.68 μm) and infrared channels(0.84-0.89 μm,10.3-11.3 μm,11.5-12.5 μm).2366 snow and ice samples,2024 cloud samples,1602 land samples and 1648 water samples were selected randomly from Arctic imageries.Land and water can be detected by spectral features.Snow-ice and cloud can be classified by textural features.The classifier is Bayes classifier.By synthesizing five d ays classifying result of Arctic snow and ice cover area,complete Arctic snow and ice cover area can be obtained.The result agrees with NOAA/NESDIS IMS products up to 70%.     

Freeze corer No. 3 for lake sediments

Freezing of sediment in situ at the lake bottom using a freeze corer has become an important method for taking samples of soft sediments aimed for detailed stratigraphic analyses. Over the past decades a variety of freeze corers have been designed, from very simple metal tubes filled with dry ice that are dropped into the sediment to high-tech samplers using electric pumps, hydraulics and liquid nitrogen. The freeze corer described here is a compromise of getting good samples without a too complicated technique. It is designed for coring from lake ice, using a steel wire with a stopper on the ice to keep the corer in fixed position during freezing. It consists of a thermos connected to a thin freeze wedge (width 15 cm, length 100 cm, max thickness 6 cm). The dry ice is kept in the thermos until the freeze wedge has been lowered into the sediment to avoid water freezing on the wedge during descent through the water column; a wet steel-wedge surface disturbs the sediment stratigraphy less than a wedge on which rapid freezing occurs. The dry ice is kept in the thermos by a trapdoor that is opened by a messenger. When the trapdoor is opened the dry ice begins to drop into the wedge, which is filled with ethanol. This process continues concurrently with the consumption of ice in the wedge until the thermos is empty. Using 6–8 kg of dry ice and 4 l of ethanol (95%), a 3-cm-thick and up to 80-cm-long crust of frozen sediment is obtained in 20–25 min on each side of the wedge. The crust is easily detached intact from the wedge using a small volume of hot water, poured inside the wedge.     

Laboratory experiments and thermal calculations for the development of a next-generation glacier-ice exploration system: Development of an electro-thermal drilling device

A next-generation drilling system, equipped with a thermal drilling device, is proposed for glacier ice. The system is designed to penetrate glacier ice via melting of the ice and continuously analyze melt-water in a contamination-free sonde. This new type of drilling system is expected to provide analysis data in less time and at less cost than existing systems. Because of the limited number of parameters that can be measured, the proposed system will not take the place of conventional drilling systems that are used to obtain ice cores; however, it will provide a useful method for quickly and simply investigating glacier ice.An electro-thermal drilling device is one of the most important elements needed to develop the proposed system. To estimate the thermal supply required to reach a target depth in a reasonable time, laboratory experiments were conducted using ice blocks and a small sonde equipped solely with heaters. Thermal calculations were then performed under a limited range of conditions. The experiments were undertaken to investigate the effects of the shape and material of the drill head and heater temperature on the rate of penetration into the ice. Additional thermal calculations were then performed based on the experimental results.According to the simple thermal calculations, if the thermal loss that occurs while heat is transferred from the heater to ice (in melting the ice) is assumed to be 50%, the total thermal supply required for heaters in the sonde and cable is as follows: (i) 4.8 kW (sonde) plus 0 W (cable) to penetrate to 300 m depth over 10 days into temperate glacier ice for which the temperature is 0 °C at all depths and to maintain a water layer along 300 m of cable; (ii) 10 kW (sonde) plus 19–32 kW (cable) to penetrate to 1000 m depth over 1 month into cold glacier ice for which the temperature is −25 °C at the surface and 0 °C at 1000 m depth and to maintain a water layer along 1000 m of cable; and (iii) 19 kW (sonde) plus 140–235 kW (cable) to penetrate to 3000 m depth over 2 months into an ice sheet for which the temperature is −55 °C at the surface and 0 °C at 3000 m depth and to maintain a water layer along 3000 m of cable. The thermal supply required for the cable is strongly affected by the thickness of the water layer, cable diameter, and the horizontal distance from the ice wall at which the ice temperature was maintained at its initial temperature. A large thermal supply is required to heat 3000 m of cable in an ice sheet (scenario (iii) above), but penetration into glacier ice (scenarios (i) and (ii) above) could be realistic with the use of a currently employed generator.     

Is There a Paleolimnological Explanation for ‘Walking on Water’ in the Sea of Galilee?

Lake Kinneret (the Sea of Galilee) is a small freshwater lake (148 km² and a mean depth of 20 m) situated in northern Israel. Throughout recent history there have been no known records of a total ice formation on its top. Furthermore, given that convection requires an initial cooling of the entire lake down to 4 °C, it is difficult to imagine how such a low-latitude lake, presently subject to two-digit temperatures during the winter, could ever freeze. Lake Kinneret is, however, unique in the sense that there are dense (warm and salty) springs along its western shore. The dynamics of the regions adjacent to these springs are investigated using a one-dimensional nonlinear analytical ice model, a paleoceanographic record of the sea surface temperature of the Mediterranean Sea, and a statistical model. We show that, because the water directly above the plume created by the salty springs does not convect when it is cooled down to 4 °C, freezing of the region directly above the salty springs was possible during periods when the climate in the region was somewhat cooler than it is today. We refer to this localized freezing situation as ‘springs ice’. The analytical ice-model involves a slowly varying approach where the ice is part of a thin fresh and cold layer floating on top of the salty and warm spring water below. During the ice formation process, the ice is cooled by the atmosphere above and warmed by the spring water below. The plumes created by the springs have a length scale of 30 m, and it is argued that, during the Younger Dryas when the air temperature in the region was probably 7 °C or more cooler than today, ‘springs ice’ (thick enough to support human weight) was formed once every 27 years or less. During the cold events 1500 and 2500 years ago (when the atmospheric temperature was 3 °C or more lower than today) springs ice occurred about once in 160 years or less. Since the duration of these cold events is of the same order as the springs ice recurrence time, there is a substantial chance that at least one springs ice occurred during these cooler periods. With today's climate, the likelihood of a springs ice is virtually zero (i.e., once in more than 10,000 years). One set of those springs associated with the freezing is situated in Tabgha, an area where many archeological features associated with Jesus Christ have been found. On this basis, it is proposed that the unusual local freezing process might have provided an origin to the story that Christ walked on water. Since the springs ice is relatively small, a person standing or walking on it may appear to an observer situated some distance away to be ‘walking on water’. This is particularly true if it rained after the ice was formed (because rain smoothes out the ice’s surface). Whether this happened or not is an issue for religion scholars, archeologists, anthropologists, and believers to decide on. As natural scientists, we merely point out that unique freezing processes probably happened in that region several times during the last 12,000 years.     

基于CloudSat资料分析北疆强降雪天气的云结构特征

利用NASA发布的2008—2015年CloudSat卫星的2B-CWC-RO、2B-CLDCLASS、2C-SNOW-PROFILE和地面气象站的观测资料,对北疆沿天山及其周边区域内21次强降雪天气降雪前和降雪期间卫星过境时云宏微观特征进行了对比分析。本文将研究区域分为了北疆沿天山西部和中部地区,分析结果表明：（1）降雪前和降雪期间的云类型以层云、积云、高层云和深对流云为主。（2）降雪前冰粒子等效半径均值分布在58.65~67.29 μm之间,冰粒子数浓度的均值在41.2~76.5 L-1之间,冰水含量的均值在25.4~135.1 mg·m^-3之间,雪水含量均值在28.0~88.0 mg·m^-3之间,降雪强度均值在0.08~0.36 mm·h^-1之间。（3）降雪前冰粒子等效半径、冰粒子数浓度、冰水含量、雪水含量和降雪强度均值分别比降雪期间大2.9 %、6.2 %、34.4 %、36.4 %和18.7 %,且高值区主要集中在北疆沿天山西部地区。     

基于CALIPSO卫星产品的中国区域异质核化冰云比例差异

利用 2012 年 1 月 ~ 2015 年 12 月 CALIPSO 冰云 3 级月平均产品（CAL_LID_L3_Ice_ Cloud） 对中国区域异质核化冰云比例进行分析,研究冰云的比例分布与季节变化特征,探究中国区域冰 云分布情况和影响冰云分布的因素。结果表明：中国南北部冰云的比例差异与地面 2 m 温度、地表 长波净辐射通量和来自地面的冰核有关。-40 ~ 0 ℃之间的冰云比例水平分布,中国大陆北部比中 国大陆南部高约 30%,季节性变化规律明显,冬季南北差异大,夏季南北差异小;云箱温度在-30 ~ 10 ℃之间的冰云,中国大陆北部比例比大陆南部平均高出约 5%,春季、秋季、冬季北部冰云比例 均高于南部,夏季温度在-8 ℃以下,南部的冰云比例超过了北部的冰云比例;在对流层（10 km 以 下）,冰云比例分布中国大陆北部比南部高,南北部之间冰云比例差异在 6 km 左右显示出峰值,约 50%,四季冰云比例随高度增加均呈现增大的趋势,且北部冰云比例均高于南部。     

新疆及周边中亚地区中亚低涡背景下云中液态水分布研究

利用2003—2014年5~9月中亚低涡发生时的AIRS Version 6 Level 2卫星资料,分析中亚低涡活动规律以及云中液态水空间分布。结果表明：（1） 北涡型中亚低涡共发生97次,南涡型共88次。中亚低涡中心更易向南移动。（2） 整体来看,云中液态水呈现山区多盆地少的趋势,在帕米尔高原、天山和昆仑山脉的山区以及咸海附近均大于100×10^-6 kg·m^-2。在准噶尔盆地、哈密盆地和塔里木盆地东部地区小于1×10^-6 kg·m^-2。（3） 中亚低涡发生路径越偏南,云中液态水柱越低。关于云中液态水柱,北涡路径较南涡路径更多。研究结果将为进一步认识中亚低涡强降水天气系统提供参考。     

1979-2012年夏季黄土高原空中云水资源时空分布

利用欧洲数值预报中心(ECMWF)发布的新一代全球全分辨率ERA-Interim再分析数据,采用经验正交函数(EOF)、小波分析、回归分析等方法,分析1979-2012年夏季黄土高原空中云水资源分布特征。结果表明:(1)夏季黄土高原空中云水资源远大于该地区实际年降水量,具有较大空中云水资源开发利用潜势;(2)空间上云水资源表现为两种模态--西北部、东南部反位相振荡(EOF1)以及中部云水资源偏多西北、东南两端偏少(EOF2),且具有显著年际变化周期;(3)黄土高原的空中云水资源主要来自东海,当水汽输送反气旋环流中心偏南(北)时,影响EOF1(EOF2)空间模态;(4)云水、云冰量峰值分别出现在700 hPa、400 hPa左右,当700 hPa存在水汽辐合及上升运动时有利于黄土高原空中云水资源开发。