大气物理与人工影响天气

2021-04-03 08:35
中国气象科学研究院年报 2021年0期
关键词:降水天气粒子

云物理与人工影响天气研究进展

Advances in Research on Cloud Physics and Weather Modification

1 人工影响天气机理与方法

1 Mechanism and method of weather modification

1.1 Cable-car measurements of vertical aerosol profiles impacted by mountain-valley breezes in Lushan Mountain, East China

In-situ field observations of vertical aerosol profiles for one month in complex terrain (Lushan Mountain,China) were carried out using a cable car, which resolved detailed vertical distributions of mountain aerosols with lowcost operation. Cable-car observations were conducted during the early morning and late afternoon,when mountain and valley winds dominated, respectively. The diurnal aerosol variations at the top and foot of Lushan Mountain were analyzed based on environmental and meteorological stations. The observations indicated that the mountain-valley breezes notably impacted the mountain-area aerosol distribution under weak weather conditions. More uniform aerosol profiles for the afternoon than the morning, with their decreasing rates of PM2.5(particles with diameters less than 2.5 μm) were 1.64 and 2.28 μg m−3hm−1, respectively. The PM2.5/PM10ratio at the mountain top increased from 0.69 to 0.81, and that at the mountain base decreased from 0.75 to 0.70 from morning to afternoon. The PM2.5concentration decreased in and around Lushan Mountain from daytime to nighttime, with the impacted diameter of the 300-m topography line being smaller than about 5 km, while the concentration increased in Jiujiang City. The relative decreasing rate of PM2.5was higher at the mountain top site (about 20%) than at the base site (about 2%) from daytime to nighttime. Moreover, uniform aerosol profiles could have been caused by regional transport through a relatively strong low-level synoptic flow (about 5 m s−1) and the mountain’s dynamic lifting effect. (Duan Jing, Chen Yong, Wang Wenling, Li Jun,Zhang Xiaopeng, Lu Guangxian, Che Yunfei, Zhong Shujun, Ma Shupo, Li Peng, An Junling, Fu Pingqing)

1.2 Radiative effects of clouds and fog on long-lasting heavy fog events in northern China

In the last decade, heavy fog events have been found to last from several days to more than a week and frequently occur in the northern China. The mechanism responsible for the long-lasting heavy fog events has not been fully understood. In this study, the radiative effects of the clouds and fog on two persistent heavy fog events on December 3–6, 2011 (Case-2011) and January 28–31, 2013 (Case-2013) are investigated based on both observations and weather research and forecasting (WRF) model. The results indicate that the radiative effects of clouds formed at middle and high levels and fog may play an important role in sustaining longlasting fog events in the northern China. The clouds formed above the fog primarily consist of ice and snow particles with a thickness of more than 3–4 km and cloud base of 3–6 km. During the daytime, the increase in solar radiation reflection caused by both clouds and fog can reduce the mean surface solar radiation by 71% in Case-2011 and 84% in Case-2013, and the contribution from clouds accounts for 18%, which may significantly weaken the surface heating from solar radiation and prevent the dissipation of fog events. While during the nighttime, the greenhouse effect of clouds and fog can increase the mean surface net radiation by 77 W m−2in Case-2011 and 68 W m−2in Case-2013, which may reduce the surface long-wave radiative cooling and prevent the further development of fog events. However, the greenhouse effect of clouds and fog during both daytime and nighttime may enhance turbulent processes and cause the fog to rise, and remain in the stable inversion layer.(Guo Lijun, Guo Xueliang, Luan Tian, Zhu Shichao, Lyu Kai)

1.3 Characteristics of raindrop size distributions during Meiyu season in Mount Lushan, East China

Meiyu front precipitation makes the region prone to frequent floods, mudslides, landslides, and other disasters, and has been the focus of ongoing and challenging meteorological research. Investigation of the raindrop size distribution (RSD) is essential for exploring the characteristics and underlying physical precipitation processes. This study investigated the precipitation characteristics in Lushan mountainous areas during the Meiyu season using laser disdrometer observed RSD data from 2016 to 2019. For the average spectra of five rain rate classes, the concentrations of large raindrops (> 0.5 mm) increased with rain rate(R), while the concentrations of small raindrops (< 0.5 mm) increased only under rain rates higher than 10 mm h−1. The gamma distribution parameters of N0(intercept parameter) and λ (slope parameter) increased/decreased with rain rate, and the shape parameter μ exhibited negative values in different rain rate classes.The distribution pattern features were N(D) = 721D−1.79e−1.20D. Distributions of the frequency for massweighted mean diameter (DM) and the logarithm of the generalized intercept parameter (lgNw) both showed a unique bimodal type, and an exceptionally high NW(lgNw> 4.5) subset with small DMwas determined.The stratiform and convective rain of RSD were also investigated. DM-R and NW-R showed similar variations in two types of precipitation. The lower µ values resulted in higher primary and constant coefficients in the quadratic polynomial fitting for the µ-λ relationship (λ = 0.0347µ2+ 1.180µ + 2.495 ). The Z-R relationship (Z for radar reflectivity factor) in stratiform precipitation characteristics was Z = 203R1.59. Further investigations showed that high NWvalues usually occurred in persistent precipitation. The RSD can be characterized as high concentrations of the first two diameter classes with narrow spectrum width (< 1 mm), which were captured during in-cloud rain with a low but continuous rain rate (< 5 mm h−1). The mountainous topography plays an important role in reshaping the characteristics of RSD and the physical processes of precipitation. (Chang Yi,Ma Qianrong, Guo Lijun, Duan Jing, Li Jun, Zhang Xiaopeng, Guo Xueliang, Lou Xiaofeng, Chen Baojun)

1.4 Aerosol and cloud properties over a coastal area from aircraft observations in Zhejiang, China

Using in-situ aircraft observations from six flights over Zhejiang on September 1 and September 4, 2016,this study investigates differences in aerosol and cloud properties between daytime and nighttime. The samples were divided into marine type and continental type based on the backward air mass trajectories and aerosol characteristics. The results show that the aerosol number concentration (Na) near the ground during daytime is higher than that at nighttime. During daytime, Nahas a significant decreasing trend near the top of the planetary boundary layer (PBL), which is not obvious during nighttime. There may be still a relative high concentration of aerosols remaining in the transition zone between the PBL and the free troposphere. Under similar liquid water content (LWC) conditions, the cloud droplet number concentration (Nc) at night is lower, and the cloud droplet effective diameter (cloud ED) is larger. The total Naof marine type aerosols is generally lower than that of continental type aerosols, but for aerosols with particle diameters greater than 1 μm, the marine type aerosols are higher. The study shows a strong negative Na-cloud ED relationship for marine type aerosols, but no obvious Na-cloud ED relationship for continental type aerosols. The number of cloud condensation nuclei (CCN)is higher under high-Naconditions; the ratio of CCN to Nareveals that the activation efficiency of marine type aerosols is higher than that of continental type aerosols. There is no obvious difference in activation efficiency between day and night. (Che Yunfei, Zhang Jing, Fang Chungang, Zhou Xu, Xue Wenhao, Hu Xiaomin, Duan Jing, Li Wei, Gao Yang, Lu Guangxian, Zhao Delong, Zhao Chuanfeng)

1.5 An airborne study of the aerosol effect on the dispersion of cloud droplets in a drizzling marine stratocumulus cloud over eastern China

Detailed airborne measurements were carried out to explore aerosol-cloud interactions and cloud microphysical properties in a drizzling marine stratocumulus cloud deck over the eastern China. Results show that the collisioncoalescence of cloud droplets, the condensation of small droplets, and the collision-induced break-up of drizzle were the dominant microphysical processes in the sampled water cloud parcel. The region in the vicinity of the cloud’s lateral boundary was spatially divided into sub-regions to better understand aerosol and droplet interactions. Relationships between the relative dispersion (ε) and the cloud’s microphysical and dynamical characteristics were also examined. A negative relation was found between ε and the cloud droplet number concentration, with ε showing a close relationship with the liquid water content (LWC) and updraft velocity. When LWC was greater than about 0.75 g kg−1, the range of ε values narrowed, and updrafts dominated. By introducing ε in the cloud droplet effect radius (Re) parameterization, we find that ε can further affect indirect forcing by changing the Redistribution for the cloud examined in this study. The dispersion effect (DE) was estimated using the effective radius ratio and the specific cloud water content. An in-depth analysis indicates that DE may offset the Twomey effect by about 12%. Two different methods of estimating the indirect effect (IE) yielded close values (0.084 and 0.077), suggesting that introducing DE into the estimation had a small influence on the IE calculation in the drizzling marine stratocumulus cloud of this study.Note that the estimated IE has a large uncertainty, given the large biases in the cloud properties measured. (Wang Fei, Li Zhanqing, Zhao Delong, Ma Xincheng, Gao Yang, Sheng Jiujiang, Tian Ping, Maureen Cribb)

1.6 Revisiting the size of nonspherical particles recorded by optical array probes with a new method based on the convex hull

In recent years, the cloud imaging probe (CIP) and precipitation imaging probe (PIP) produced by droplet measurement technologies (DMT) have been introduced by a number of meteorological research and operation centers in China. The supporting software provided by DMT, i.e., PADS (particle analysis and display system),cannot output detailed information on each individual particle, which definitely limits the in-depth utilization of cloud and precipitation particle image data in China. In this paper, particle-by-particle information was extracted by decompressing the CIP and PIP original particle image data, based on which a new definition of the dimension for nonspherical particles is proposed by using the area of the convex hull enclosing a particle to obtain the equivalent diameter of a circle with equal area. Based on the data detected during one flight in Inner Mongolia, the particle size distribution obtained using the new particle size definition and that used by the other four existing definitions are compared. The results show that the particle number concentration calculated using different particle size definitions can vary by up to an order of magnitude. The result obtained based on the new particle size definition is closest to that calculated with the area-equivalent diameter definition.(Zhang Rong, Zhou Xu, Li Hongyu, Li Hanchao, Wei Lei, Gao Yang, Xia Qiang, Wang Xiangyu)

1.7 Satellite estimates and subpixel variability of rainfall in a semi-arid grassland

Uncertainties in satellite rainfall estimation may derive from both the local rainfall characteristics and its subpixel variability. To study this issue, micro rain radars and a rain gauge network were deployed within a 9-km satellite pixel in the semi-arid Xilingol grassland of China in summer 2009. The authors characterized the subpixel variability with the coefficient of variation (CV) and evaluated the satellite rainfall estimation for this semi-arid area. The results showed that rainfall events with a high CV were mostly convective with a small amount of rainfall. Spatially inhomogeneous rainfall was most likely to occur at the edges of small clouds producing rain. The performance of the TRMM (tropical rainfall measuring mission) 3B42V7 product for daily rainfall was better than that of the CMORPH (Climate Prediction Center morphing technique) and PERSIANN(precipitation estimation from remotely sensed information using artificial neural networks) products, although the TRMM product tended to overestimate rainfall in a lake area of the semi-arid grassland. (Chen Yong, Duan Jing, An Junling, Liu Huizhi, Ulrich Görsdorf, Franz H. Berger)

1.8 A hypergraph-embedded convolutional neural network for ice crystal particle habit classification

In the field of weather modification, it is important to accurately identify the ice crystal particles in ice clouds. When ice crystal habits are correctly identified, cloud structure can be further understood and cloud seeding and other methods of weather modification can be used to change the microstructure of the cloud.Consequently, weather phenomena can be changed at an appropriate time to support human production and quality of life. However, ice crystal morphology is varied. Traditional ice crystal particle classification methods are based on expert experience, which is subjective and unreliable for the identification of the categories by threshold setting. In addition, existing deep learning methods are faced with the problem of improving classification performance on datasets with unbalanced sample distributions. Therefore, we designed a convolutional neural network (CNN) embedded with a hypergraph convolution module, named Hy-INet. The hypergraph convolution module can effectively capture information from hypergraphs constructed from local and global feature spaces and learn the features of small samples in ice crystal datasets that have unbalanced sample numbers. Experimental results demonstrate that the proposed method can achieve superior performance in the classification task of ice crystal particle habits.(Liao Mengyuan, Duan Jing, Zhang Rong, Zhou Xu, Wu Xi, Wang Xin, Hu Jinrong)

1.9 Temporospatial distribution and trends of thunderstorm, hail, gale, and heavy precipitation events over the Tibetan Plateau and associated mechanisms

Temporospatial distribution and trends of thunderstorm, hail, gale, and heavy precipitation events over the Tibetan Plateau (TP) as well as the associated mechanisms with observational data from 1979 to 2016 are investigated, which have not been fully studied under a changing climate. The results indicate that thunderstorm, hail, and gale events over the whole TP show significant decreasing trends, while heavy precipitation events have an insignificant increasing trend. The southeast and central south subregions have obvious significant decreasing trends in thunderstorm, hail, and gale events, while the northeast subregion has a significant increasing trend in heavy precipitation events. It is found that the atmospheric circulation anomaly caused by the northwestern Atlantic sea surface temperature (SST) anomaly associated with the North Atlantic oscillation (NAO) should be responsible for these changes. A strong wave train triggered by the northwestern Atlantic SST anomaly propagates from the northern Atlantic to East Asia through Europe, and induces a more upper-level warming over the TP and an anomalous anticyclonic circulation near the Lake Baikal, resulting in a more stable atmosphere and blocking effect, which forces the midlatitude westerlies and associated cold air to shift poleward. The weakened cold-air advection over the TP decreases the baroclinic instability and convection initiation, and finally causes the significant decreasing trends in severe weather events. On the other hand, the enhanced easterly winds in the southern flank of the anticyclonic circulation can significantly increase the water vapor flux from the eastern boundary of the TP and heavy precipitation events in the northeast subregion. (Tang Jie, Guo Xueliang, Chang Yi, Lu Guangxian, Qi Peng)

1.10 Microphysical characteristics of precipitating cumulus cloud based on airborne Ka-band cloud radar and droplet measurements

Based on cloud-probe data and airborne Ka-band cloud radar data collected in Baoding on 5 August 2018, the microphysical structural characteristics of cumulus (Cu) cloud at the precipitation stage were investigated. The cloud droplets in the Cu cloud were found to be significantly larger than those in stratiform(STF) cloud. In the Cu cloud, most cloud particles were between 7 and 10 μm in diameter, while in the STF cloud the majority of cloud particles grew no larger than 2 μm. The sensitivity of cloud properties to aerosols varied with height. The cloud droplet effective radius showed a negative relationship with the aerosol number concentration (Na) in the cloud planetary boundary layer (PBL) and upper layer above the PBL. However, the cloud droplet concentration (Nc) varied little with decreased Nain the high liquid water content region above 1500 m. High Navalues between 300 and 1853 cm−3were found in the PBL, and the maximum Nawas sampled near the surface in August in the Hebei region, which was lower than that in autumn and winter. High radar reflectivity corresponded to large FCDP (fast cloud droplet probe) particle concentrations and small aerosol particle concentrations, and vice versa for low radar reflectivity. Strong updrafts in the Cu cloud increased the peak radius and Nc, and broadened the cloud droplet spectrum; lower air temperature was favorable for particle condensational growth and produced larger droplets.(Wei Lei, Huang Mengyu, Zhang Rong, Lyu Yuhuan,Hou Tuanjie, Lei Hengchi, Zhao Delong, Zhou Wei, Fu Yuan)

1.11 Characteristics of raindrop size distributions in Chongqing observed by a dense network of disdrometers

This study investigates the characteristics of raindrop size distribution (RSD) including the temporal and spatial variabilities and the summer rain RSD features using 34 Parsivel disdrometers data from January 2015 to January 2016 in Chongqing, an inland municipality in Southwest China. The observed RSDs are fitted with the gamma distribution (N(D) = N0Dμe−λD) in this study. Rainfall in summer differs greatly from winter with larger rain rate, rain water content and variabilities. From winter to summer, raindrop sizes increase as the frequency of convective rain increases, and the diurnal variabilities of raindrop sizes are greatly enlarged. The spatial variabilities of N0, λ and μ are relatively weak and change little in summer. The summer rainfall RSD characteristics and parameter relationships in Chongqing are different from other regions (Nanjing, Beijing,Zhuhai and Daocheng) in China. A novel diagnosed relation between the shape parameter of the gamma distribution (μ) and the mean volume diameter (Dv) is proposed based on the large amount of observations,which allows for a wider range of the mean volume diameter of raindrops compared to traditional μ-λ relations in microphysics parameterizations. (Liu Xuancheng, Xue Lulin, Chen Baojun, Zhang Yixuan)

1.12 Numerical simulation and the underlying mechanism of a severe hail-producing convective system in East China

A severe convective system that produced egg-sized hail in Jiangsu Province in East China on April 28,2015 was simulated using a cloud-resolving weather research and forecasting model with the spectral bin microphysics scheme. The simulation reproduced the two stages of the convective system: the linear convective system (LCS) and the bow echo system (BES) stages. During the LCS stage, the intensity of updrafts was slightly stronger than that in the BES stage, with abundant supercooled water above the −20 layer, and graupel and hail mainly generated in this period. The microphysical budget analyses and size distribution characteristics of hail were studied within one cell that produced hail during the LCS. It was suggested that hail mainly formed through water-graupel collision and increased in size by collecting liquid water. Hail particles with smaller diameter were located around the perimeter of the main updrafts, while larger ones were distributed at the left edge of the updrafts. Trajectories and size growth processes of hailstones within the chosen cell were calculated by a three-dimensional hail growth model, and it was found that hails originated from the middle levels on the east side of the updrafts, and were transformed westward and downward to the lower levels. They continued to ascend along the left edge of the updrafts and experienced one or more updown recycles and fell down to the ground on the west side of the updrafts. (Lei Yin, Fan Ping, Xu Huanbin,Chen Baojun)

1.13 Characteristics of deep convective systems and initiation during warm seasons over China and its vicinity

The spatiotemporal statistical characteristics of warm-season deep convective systems, particularly deep convective systems initiation (DCSI), over China and its vicinity are investigated using Himawari-8 geostationary satellite measurements collected during April-September from 2016 to 2020. Based on a satellite brightness temperature multiple-threshold convection identification and tracking method, a total of 47593 deep convective systems with lifetimes of at least 3 h were identified in the region. There are three outstanding local maxima in the region, located in the southwestern, central and eastern Tibetan Plateau and Yunnan-Guizhou Plateau, followed by a region of high convective activities in South China. Most convective systems are developed over the Tibetan Plateau, predominantly eastward-moving, while those developed in Yunnan-Guizhou Plateau and South China mostly move westward and southwestward. The DSCI occurrences become extremely active after the onset of the summer monsoon and tend to reach a maximum in July and August, with a diurnal peak at 11:00‒13:00 LST in response to the enhanced solar heating and monsoon flows.Several DCSI hotspots are identified in the regions of inland mountains, tropical islands and coastal mountains during daytime, but in basins, plains and coastal areas during nighttime. DCSI over land and oceans exhibits significantly different sub-seasonal and diurnal variations. Oceanic DCSI has an ambiguous diurnal variation,although its sub-seasonal variation is similar to that over land. It is demonstrated that the high spatiotemporal resolution satellite dataset provides rich information for understanding the convective systems over China and vicinity, particularly the complex terrain and oceans where radar observations are sparse or none, which will help to improve the convective systems and initiation nowcasting. (Li Yang, Liu Yubao, Chen Yun, Chen Baojun, Zhang Xin, Wang Weisheng, Shu Zhuozhi, Huo Zhaoyang)

1.14 Hydrometeor and latent heat nudging for radar reflectivity assimilation: Response to the model states and uncertainties

Radar data are essential to convection nowcasting and nudging-based radar data assimilation through diabatic initialization is one of the most effective approaches for forecasting convective systems with numerical weather prediction (NWP) models, used at several advanced global weather centers. It is desired to assess the uncertainty and physical consistency of this assimilation process. This paper investigated impacts of relaxation coefficient, radar data update intervals and continuous assimilation time duration and addressed the key issues and possible solutions of the radar data assimilation based on the WRF hydrometeor and latent heat nudging (HLHN) developed at the National Center for Atmospheric Research (NCAR). It is revealed that excessively large re-laxation coefficient forced the model to observations with a tendency greater than the physical terms of the convection, causing the dynamic imbalances and serious convection “ramp-down”right after the free forecast starts. Assimilating high update frequency radar data can make the tendency terms moderate and sustained thereby maintaining the assimilation effect and reducing fortuitous convection. HLHN requires a minimum continuous assimilation duration to contain the initial forced disturbance of the model. For a summer Meiyu precipitation case studied, the minimum duration is about 1 h. Appropriate selection of the HLHN parameters is able to effectively improve the temperature, humidity, and dynamic fields of the model. In addition, several issues still remain to be solved to further enhance HLHN.(Huo Zhaoyang, Liu Yubao, Wei Ming, Shi Yueqin, Fang Chungang, Shu Zhuozhi, Li Yang)

1.15 Vertical distributions of aerosol microphysical and optical properties based on aircraft measurements made over the Loess Plateau in China

Aerosol microphysical properties, scattering and absorption characteristics, and in particular, the vertical distributions of these parameters over the eastern Loess Plateau, were analyzed based on aircraft measurements made in 2020 during a summertime aircraft campaign in Shanxi, China. Data from six flights were analyzed.Statistical characteristics and vertical distributions of aerosol concentration, particle size, optical properties,including aerosol scattering coefficient (σsp), backscattering ratio (βsc), Ångström exponent (α), single-scattering albedo (SSA), partially-integrated aerosol optical depth (PAOD), and black carbon concentration (BCc),were obtained and discussed. Mean values of aerosol particle number concentration (Na), particle volume concentration (Va), mass concentration (Ma), surface concentration (Sa), and particle effective diameter (EDa)were 854.92 cm−3, 13.37 μm3cm−3, 20.06 μg m−3, 170.08 μm3cm−3, and 0.47 μm, respectively. Mean values of BCc, σsp(450, 525, 635 nm), βsp(525 nm), α (635/450), and SSA were 1791.66 ng m−3, 82.37 Mm−1at 450 nm,102.57 Mm−1at 525 nm, 126.60 Mm−1at 635 nm, 0.23, 1.47, and 0.92, respectively. Compared with values obtained in 2013, Nadecreased by 60% and Madecreased by 45%, but the scattering coefficients increased in different degrees. In the vertical direction, aerosol concentrations were higher at lower altitudes, decreasing with height. Vertical profiles of σsp, βsp, α (635/450), and BCc measured during the six flights were examined.Two peaks in Nawere identified near the top of the boundary layer and between 2000 and 2200 m. Fine particles with EDa smaller than 0.8 μm are dominant in the boundary layer and coarse aerosols existed aloft.Aerosol scattering properties and BCc in the lowest layer of the atmosphere contributed the most to the total aerosol radiative forcing. SSA values were greater than 0.9 below 2500 m, with lower values at higher levels of the atmosphere. On lightly foggy days, SSA values were greater than 0.9, and aerosols played a cooling role in the atmosphere. On hazy days, lower level SSA values were generally greater than 0.85, with aerosols likely having a warming effect on the atmosphere. The 48-hour backward trajectories of air masses during the observation days showed that the majority of aerosol particles in the lower atmosphere originated from local or regional pollution emissions, contributing the most to the total aerosol loading and leading to high values of aerosol concentration and radiative forcing. (Cai Zhaoxin, Li Zhanqing, Li Peiren, Li Junxia, Sun Hongping,Yang Yiman, Gao Xin, Ren Gang, Ren Rongmin, Wei Jing)

1.16 Assimilation of ground-based microwave radiometer on heavy rainfall forecast in Beijing

Ground-based microwave radiometers (MWRPS) can provide continuous atmospheric temperature and relative humidity profiles for a weather prediction model. We investigated the impact of assimilation of groundbased microwave radiometers based on the rapid-refresh multiscale analysis and prediction system-short term(RMAPS-ST). In this study, five MWRP-retrieved profiles were assimilated for the precipitation enhancement that occurred in Beijing on 21 May 2020. To evaluate the influence of their assimilation, two experiments with and without the MWRPS assimilation were set. Compared to the control experiment, which only assimilated conventional observations and radar data, the MWRPS experiment, which assimilated conventional observations, the ground-based microwave radiometer profiles and the radar data, had a positive impact on the forecasts of the RMAPS-ST. The results show that in comparison with the control test, the MWRPS experiment reproduced the heat island phenomenon in the observation better. The MWRPS assimilation reduced the bias and RMSE of 2-meter temperature and 2-meter specific humidity forecasting in the 0–12 h of the forecast range. Furthermore, assimilating the MWRPS improved both the distribution and the intensity of the hourly rainfall forecast, as compared with that of the control experiment, with observations that predicted the process of the precipitation enhancement in the urban area of Beijing.(Qi Yajie, Fan Shuiyong, Li Bai, Mao Jiajia,Lin Dawei)

1.17 How do multiscale interactions affect extreme precipitation in eastern central Asia?

The variability of extreme precipitation in the eastern central Asia (ECA) during summer (June–August) and its corresponding mechanisms were investigated from a multiscale synergy perspective. Extreme precipitation in ECA displayed a quasi-monopole increasing pattern with abrupt change since 2000/2001,which was likely dominated by increased high-latitude North Atlantic SST anomalies as shown by diagnosed and numerical experiment results. Increased SST via adjusting the quasi-stationary wave train that related to the negative North Atlantic oscillation (NAO) and the east Atlantic/western Russia (EA/WR) pattern guided the cyclonic anomaly in central Asia, deepened the Lake Balkhash trough, and enhanced the moisture convergence in ECA. These anomalies also exhibited interdecadal enhancement after 2000. On the synoptic scale, two synoptic transient wave trains correlated with extreme precipitation in ECA by amplifying the amplitude of the quasi-stationary waves and guiding transient eddies in ECA. The induced transient eddies and deepened Lake Balkhash trough strengthened positive meridional vorticity advection and local positive vorticity,which promoted ascending motions, and guided the southerly warm moisture in ECA especially after 2000.Meanwhile, additional mesoscale vortices were stimulated and strengthened near the Tianshan Mountain in front of the wave trough, which, together with the enhanced meridional circulation, further increased extreme precipitation in ECA.(Ma Qianrong, Zhang Jie, Ma Yujun, Asaminew Teshome Game, Chen Zhiheng, Chang Yi, Liu Meichen)

1.18 人工影响天气碘化银催化剂研究进展

碘化银(AgI)类催化剂是人工影响天气外场试验和业务作业中使用最广泛的催化剂,其核化效率和核化机制在很大程度上影响催化效果。在总结美国、中国和欧洲多个国家利用云室和风洞研究AgI类催化剂的核化机制、核化阈温及成核率的室内试验成果的基础上,梳理利用室内试验成果发展的AgI数值催化模式,旨在为下一步优选新型高效AgI类催化剂和改进数值催化模式提供借鉴。AgI类催化剂核化机制包括凝华核化、接触冻结核化、凝结冻结核化和浸没冻结核化,其核化过程受大气温湿条件、催化剂粒子大小、成分等多种因素影响,并与催化剂粒子的燃烧溶液法、燃烧焰剂法和爆炸法等发生方式有关。目前国内外使用的AgI类催化剂含有不同成分,有多种催化剂粒子产生方式,催化剂粒子的核化机制和成核率有很大差异。将来应重点基于高性能云室和风洞,分析不同催化剂配方的核化机制和成核率,优选新型高效催化剂,改进AgI数值催化模式。(楼小凤,傅瑜,苏正军)

1.19 青藏高原夏季对流云微物理特征和降水形成机制

青藏高原对我国天气、气候和水循环过程有重要影响。利用第三次青藏高原大气科学试验(TIPEX-Ⅲ)2014年7月在那曲地区的飞机观测数据,研究青藏高原夏季对流云和降水的微物理特征及降水形成机制。飞机探测的云系主要为初生或发展阶段的冰水混合云,云滴数浓度低于平原、海洋地区1~2个量级,云内存在大量大云滴和雨滴,过冷水含量高。大粒子(D≥50 μm)数浓度量级为100~101/L,云内上升气流速度集中在1~4 m/s。青藏高原云滴谱主要呈双峰型,云内冰相粒子多为密实、不透明的霰粒子,云内凇附过程显著。云内暖雨过程产生的大云滴和雨滴有利于冰相过程,尤其是凇附过程的产生,使得青藏高原云更易产生降水。此外,残留云系与对流云有着较为类似的微物理特征。(常祎,郭学良,唐洁,卢广献,亓鹏)

1.20 基于探空云识别方法的云垂直结构分布特征

云的垂直结构特征作为云重要的宏观特征之一,直接决定了云的类型,进而通过发射和吸收辐射的方式影响着地气系统的能量收支平衡,因此对云垂直结构特征的研究一直都是云物理研究的一个重要方向。作为观测云垂直结构特征的一种方式,探空气球通过获取沿路径方向高分辨率的廓线信息,采用一定反演方法从而能够较为准确地识别云的垂直结构。本文即利用我国业务布网探空站的观测资料,采用相对湿度阈值法识别云垂直结构,并同激光云高仪、“风云四号”静止卫星和毫米波云雷达对识别的云结构特征量进行了一致性检验。在此基础上,统计分析了2015—2017年单层、两层和三层云的垂直结构分布特征、日变化和季节变化特征以及全国区域分布特征。结果表明:(1)整体分布上,单层云在垂直方向上出现的高度范围介于多层云的高度范围内,并且随着云层数的增加,云在垂直方向上更为伸展,即高层云越高,低层云越低。(2)在日变化中,中午单层和多层云中最低层云的云底高度均高于早晨,而夜间单层和多层云中最高层云的云顶高度则高于早晨和中午,同时中间层云厚的变化要小于最上层和最下层云厚的变化。(3)在季节变化中,夏季云量较其他季节更多,云体发展也更为深厚,表明温暖的大气条件更有利于云的形成和发展。(4)我国云垂直结构分布特征具有明显的纬向变化趋势,从以青藏高原为中心的西南地区的云底较高云体较薄的云,逐步过渡到以东南沿海地区为中心的云底较低云体较为深厚的云,表明不同地形和气候带的差异与不同云类型的分布直接相关。(李琦,蔡淼,周毓荃,唐雅慧,欧建军)

1.21 六盘山地区一次低槽低涡云系结构及其降水机制的数值模拟研究

六盘山是西北重要的水源涵养林基地,干旱少雨制约了该地区农业和经济发展。作为该地区人工增雨技术研究的基础,本文利用WRF模式对2018年8月21日发生在宁夏南部六盘山区的一次降水天气过程进行了数值模拟。根据模拟结果结合实测资料,分析了造成此次强降水过程的有利环流形势场,重点讨论了山区降水云系的微物理结构以及降水形成机制。结果表明:降水是在高空槽配合低涡的动力场作用下形成的,受六盘山地形的阻挡作用,低层低涡系统移速落后于高空槽;垂直方向上云系呈现“催化—供给”的分层结构,但在云系不同部位,各层水凝物配置不同,导致冷暖云过程对降水的贡献差异;六盘山东部迎风坡降水强于西坡。霰粒子融化和云水碰并是地面降水的主要来源;碰冻过冷雨水是霰增长的主要过程。迎风坡云水层深厚,含水量高,一方面促进过冷层中霰粒子的碰冻增长过程,一方面为雨滴碰并增长提供充沛的云水条件,即同时增强了冷暖云降水过程。地形对云的发展和降水的形成有明显影响,当降低地形高度后,云水量减少,暖云过程减弱,同时也影响了霰粒子的增长过程。(高亮书,姚展予,贾烁,张沛,安琳,常倬林,桑建人,赵文慧,王伟健)

1.22 祁连山春季一次层状云降水的雨滴谱分布及地形影响特征

祁连山是青藏高原东北部重要的生态屏障和冰川与水源涵养生态功能区,是黄河流域重要水源产流地,但针对该地区的云和降水过程研究很少。本文利用祁连山地区11个 Parsivel2雨滴谱仪的观测数据,研究了祁连山地区春季一次层状云降水过程的雨滴谱分布及地形影响特征。此次降水过程主要受短波槽影响,降水时空差异较大。雨滴谱观测数据表明,此次降水过程的雨滴等效直径(Dm)较小,雨滴谱数浓度(NT)与Dm随海拔高度升高分别呈增加和减小的趋势,低海拔站点lgNw(Nw为雨滴谱截断参数)和Dm分布有着明显的层状云降水特征,而整个祁连山地区在同样Dm下有着更高的Nw。低海拔站点由于碰并和小雨滴的蒸发,因此有着更少的小雨滴(<1 mm)和更多的大雨滴,而高海拔站点由于距离云底较近或位于云内,云滴尺度小且浓度大,Dm随R(R为降水强度)增大变化趋势不明显。M-P分布和Gamma分布在低海拔站点的拟合效果要优于高海拔站点,相较于Gamma分布,M-P分布对高海拔站点的小雨滴和大雨滴浓度有一定的高估和低估,因此更适用于高海拔站点雨滴谱的描述。对比于低海拔站点,高海拔站点的μ-λ(μ、λ分别为Gamma分布的形状参数和斜率参数)关系与相关研究的结果较为接近,但在λ较小(<40 mm−1)时拟合结果较为接近。受海拔高度与云底的相对位置和地形的影响,祁连山地区的Z-R(Z为雷达反射率因子)关系与其他地区或研究有着较大的区别。(程鹏,常祎,刘琴,王研峰,李宝梓,陈祺,罗汉)

1.23 华北地区一次气溶胶与浅积云微物理特性的飞机观测研究

2014年8月15日,山西省人工降雨防雹办公室在山西忻州开展了气溶胶和浅积云的飞机观测,本文利用机载云物理资料,详细分析了华北地区气溶胶、云凝结核(CCN)和浅积云微物理特性及其相互影响。主要结论有:(1)此次过程的边界层高度约为3600 m,不同层结情况下,0.1~3 μm尺度范围内的气溶胶粒子浓度Na、有效直径Da和CCN数浓度的垂直廓线明显不同,近地面Na可达2500 cm−3。(2)CCN的主要来源为积聚模态、爱根模态或者核模态的气溶胶颗粒,0.2%过饱和度下,气溶胶活化率(AR)在各高度层的结果变化不大;0.4%过饱和度下,AR随着高度增加而降低。(3)后向轨迹模式分析表明,2 km以下的气溶胶主要来自于当地城市排放,由细颗粒污染物组成;2 km以上的气溶胶主要来源于中国西北和蒙古地区的沙漠,由亚微米沙尘组成,溶解度相对较低,可作为潜在的冰核。(4)本文细致分析了两块相邻浅积云(Cu-1 和 Cu-2)的云物理特性。Cu-1云底高度约4500 m,云厚约600 m,云体松散,夹卷较多;云中液态含水量(LWC)基本保持在0.5 g/m3,云粒子浓度Nc平均值为278.3 cm−3,云滴有效直径Dc整体在15 μm以内;毛毛雨滴粒子浓度最大值为0.002 cm−3,云中几乎无降水粒子;粒子谱宽随着高度增加而增大,主要集中在30 μm以内。Cu-2云底高度约3900 m,云厚约1200 m,云体密实;云中过冷水丰沛,LWC有多个超过1 g/m3的区域,云顶附近出现冰晶,云中粒子从凝结增长状态直接进入到混合相态;积云内部粒子水平分布不均,同一高度Nc相差较大,最大可达1240 cm−3。Dc随着高度增加而增大;粒子谱宽随着高度增加而拓展,最大可达1100 μm,谱型由单峰向多峰转变;降水粒子和冰晶图像大多为霰粒子、针状和板状。(蔡兆鑫,蔡淼,李培仁,李军霞,孙鸿娉,杨怡曼,任刚,高欣)

1.24 祁连山一次地形云降水微物理特征飞机观测

祁连山是我国西北地区重要的生态屏障,地形云是祁连山主要降水云系,加强对祁连山云微物理过程的认识,对科学有效开展人工增雨作业、改善生态环境具有重要意义。利用2020年8月29日祁连山一次地形云降水过程的飞机观测数据,研究祁连山地区夏季云降水过程的微物理特征。此次降水过程云系呈明显的分层结构,云底高度为4000 m,整层含水量较丰富,云水大值区出现在4500~5300 m高度,与云滴高浓度区对应,云水含量主要由粒子直径为15~20 μm的云滴粒子贡献。小云粒子和大云粒子平均浓度分别为7.54 cm-3和0.86 cm-3,有效直径平均值分别为11.02 μm和198.11 μm,呈现出浓度小、直径大的特征。云系翻越祁连山过程中南北坡云微物理特征有明显变化,北坡(背风坡)粒子浓度、直径和液态水含量明显大于南坡(迎风坡)。祁连山地区不同高度小云粒子谱呈单峰型分布,Gamma分布可较好拟合直径小于50 μm的云滴谱,直径大于50 μm的云粒子谱更符合幂指数分布。凝华和聚并是冰相层冰雪晶的增长机制,混合层冰晶增长以贝吉龙过程为主,并伴有凇附和聚并生长。(程鹏,罗汉,常祎,甘泽文,张丰伟,刘维成,陈祺,冒立鑫)

2 关键技术研发与业务应用转化

2 Key technology development and application

2.1 FACT: an air-ground communication framework for seeding quality control of aircraft

A new type of air-ground communication application framework named FACT (framework for airground communication technology with weather-modification aircraft) is presented to track and command weather-modification aircraft to perform ideal cloud seeding. FACT provides a set of solutions from three perspectives, namely, onboard, onground and air-to-ground, with the core purpose of solving the problems of the rapid exchange of information, contract analysis and identifying potential seeding areas when flight plans and meteorological conditions change. On board, the observed data are processed centrally and transmitted downward through air-to-ground communication. The real-time application and sharing of aircraft detection data are strengthened on the ground, and potential areas of operation are automatically identified based on ground data. The communication between the air and the ground achieves a technical breakthrough by realizing double satellite links, adaptive data transmission and VPN channel encryption. Additionally, an application based on FACT is designed and implemented for the real-time command of weather-modified aircraft. This approach has become the key air-to-ground communication system support for more than 40 Chinese aircraft and the big data service support center of airborne data to ensure improved operation of weather-modification aircraft in China.(Li Dequan, Li Jiming, Zhou Xu, Hu Jinrong, Wang Xin, Duan Jing)

2.2 Seasonal variations of aerosol number concentration and spectrum distribution in Nanjing

In this paper, the diurnal variations and seasonal variations of the aerosol spectrum distribution, as well as their correlations with meteorological factors in Nanjing in different seasons, are analysed. The results show that the number concentration of ultrafine particle in size of 0.01‒0.1 μm accounts for over 60% of the total particle concentration in each season. The Aitken mode (AIM) particles dominate the changes of aerosol in Nanjing, which are mainly from traffic sources. Both local emissions and external transportation make important contributions to the air pollution in Nanjing. The southerly and easterly airflows are conducive to the accumulation of pollutants. The number concentrations of the AIM and Accumulation mode (ACM) particles decrease with the increasing wind speed, while the variation trend of the Nucleation mode (NUM) particles is opposite. The removal efficiency of precipitation for the ACM particles is much lower than that on the other three modes.(Jiang Qi, Wang Fei, Ying Chun, Zhu Bin)

2.3 Increasing cloud water resource in a warming world

Under global warming, terrestrial water resources regulated by precipitation may become more unevenly distributed across space, and some regions are likely to be highly water-stressed. From the perspective of the hydrological cycle, we propose a method to quantify the water resources with potential precipitation capacity in the atmosphere, or hydrometeors that remain suspended in the atmosphere without contributing to precipitation, namely cloud water resource (CWR). During 2000–2017, CWR mainly concentrates in the middle-high latitudes which is the cold zone of the Köppen classification. In a warming world, CWR shows a significant increase, especially in the cold zone. Climate change with Arctic amplification and enhanced meridional circulation both contribute to the change of CWR through influencing hydrometeor inflow. By studying the characteristics of CWR and its influencing mechanisms, we demonstrate a potential for human intervention to take advantage of CWR in the atmosphere to alleviate terrestrial water resource shortages in the future.(Cheng Jingya, You Qinglong, Zhou Yuquan, Cai Miao, Nick Pepin, Chen Deliang, Amir AghaKouchak, Kang Shichang, Li Mingcai)

2.4 层状云催化宏微观物理响应的数值模拟研究

层状云系是进行人工增雨开发利用空中云水资源的重要对象,增雨作业需要有科学可行的技术指标来指导实际作业的科学实施,而合理准确评估人工增雨作业的效果也是需要解决的重要课题,通过数值模式合理地仿真模拟实际催化作业的过程,进而研究增雨作业后云和降水的一系列宏微观特征的变化及其机理,是建立和改进催化作业技术的必要途径,也是评估实际人工增雨作业效果的有效手段。本文使用三维中尺度冷云催化模式对2014年4月15日河北省一次层状云降水的飞机催化作业过程进行了仿真模拟,力图对实际作业过程进行合理再现,通过对模拟结果的分析,研究飞机播撒的AgI(Silver iodide)催化剂在空中的扩散传输特征,分析催化对云和降水宏微观特性的影响,并对此次飞机催化作业的增雨效果进行评估。研究结果表明:播撒的AgI催化剂烟羽扩展的水平尺度可达数十公里以上,垂直方向上,大部分AgI粒子则主要集中在作业层上下约1 km的厚度范围内,AgI粒子的向上输送明显强于向下的输送;催化后云中的冰晶和雪粒子明显增加,导致催化模拟前期的霰增长受到抑制,之后随着霰碰并雪过程及零度层附近冰相粒子淞附过程的增强,云中霰的总量逐渐增加;催化作业后,催化云的雷达回波强度有明显增强,且随时间变化表现出不同的结构特征;催化导致地面降水出现先减少后增加的时间变化特征,催化后3 h,作业影响区向作业区下游扩展100 km以上,总体呈现减雨—增雨的区域分布特征;数值模拟评估表明,整个评估区内的净增雨量达到3.6×107kg,平均增雨率为1.1%,暖层霰粒浓度和尺度的增加是降水增加的主要原因。由于作业目标云系的催化条件一般,而播撒的AgI剂量偏大,造成增雨作业效果偏低。(刘卫国, 陶玥, 周毓荃)

2.5 一次对流云人工消减雨作业云条件预报和作业预案合理性分析

为做好固定目标时段和区域的人工消减雨作业,利用云降水显式预报系统(CPEFS_V1.0)对云系性质和结构、移速移向及演变、降水机制等云条件进行预报。预报结果显示:2017年8月8日影响呼和浩特的云系性质为分散性对流云,具有冷暖混合云结构,云中上升气流强,对流单体水平尺度约几十公里,生命史1.5~3 h,云顶高度约10 km、云底高度约3 km,0 ℃高度约为4.3 km;微观方面冰相水凝物雪、霰含量高,暖区云水含量少,云中过冷水含量最大达0.7 g/kg,过冷水丰沛区域冰晶数浓度低,以冷云降水为主。初生在呼和浩特特定防护区西北方向的对流云团快速发展东移南压影响核心保障区,移速30~40 km/h。卫星、雷达等实况监测显示8日的云系为分散性对流云,预报对流云的生成时间比实况偏晚1~2 h,移向与实况一致,移速偏慢10~20 km/h。在5400 m高度处(-8 ℃),机载云物理探测的液水含量最大为0.6 g/m3,预报与实况接近。根据预报的云系条件制定作业预案指出,在核心保障区的偏西北方向50~30 km处进行重点布防,适宜在5.1~7.0 km高度处实施AgI过量催化,8日上午飞机在第一道防线的弱回波区开展探测作业,地面作业集中在第三道防线对流云初生阶段实施过量播撒,以达到消减雨作业的目标。根据预案,提前24 h在核心保障区偏西北方向的第三道防线增设了5个地面移动作业点,这些作业点8日及时实施了消减雨作业。总体看来,此次云条件预报正确、预案制定合理,及时为外场实施消减雨作业提供了支撑。(史月琴, 刘卫国, 王飞, 高扬)

2.6 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2.12×108kg,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。(刘卫国, 陶玥, 周毓荃, 党娟, 谭超, 高扬)

2.7 飞机积冰的云层特征个例分析

利用卫星、雷达、探空、飞机等观测资料和NCEP再分析资料,以及数值模拟结果,对 2016年3月8—9日我国安庆地区的云系特征和飞机积冰气象条件进行了分析。结果表明,此次飞机积冰发生在寒潮天气背景下,强冷空气造成锋面逆温。实测飞机积冰现象出现在对流降雨结束后的层积云层顶部,积冰高度对应高空锋区逆温层底部,云顶高度约3.4 km,云顶温度-10 ℃,无降水和雷达回波,云中主要为过冷水,丰沛时段飞机观测过冷水平均值为 0.36 g/m3,基本无冰相粒子。当云顶高度再度抬升,冰相粒子增多时,过冷水含量减少,不利于积冰现象发生。CPEFS模式模拟出了与实测比较一致的云宏微观结构。(孙晶, 蔡淼, 王飞, 史月琴)

2.8 新疆春季两次直升机积冰气象条件分析

利用卫星、雷达、探空、地面等观测资料和NCEP再分析资料,以及数值模拟结果,对2018年3月新疆昌吉地区两次飞机积冰探测试验过程的云系特征和积冰气象条件进行了分析。 结果表明,两次直升机积冰过程影响系统分别为500 hPa低涡和500 hPa浅槽,地面有冷锋配合。积冰时段处于低涡系统发展前期阶段和低槽系统发展中期阶段。积冰云层均为中低云云层,云顶高度为4 km,云顶温度为-15~-25 ℃,云底高度为1.5 km,云层厚度为1~3 km,光学厚度大于12,雷达回波特征不明显,无回波或者回波强度在10 dBz以下。3月27日浅槽锋面过程云顶有逆温。CPEFS模式模拟云微观结构表明,积冰云层是以过冷水为主,冰相粒子含量很少。 根据直升机特性修改后的CIP初始积冰潜势算法较好地体现了这两次层积云飞机积冰特征,对于稳定性云层的积冰潜势具有指示意义。结合飞行速度等参量计算的积冰强度与实况基本吻合。(孙晶, 谭超, 周毓荃, 刘政, 黄珺, 王泽林)

2.9 DMT机载云粒子图像形状识别及其应用

利用机载云粒子探测设备入云进行观测是目前获取云粒子微物理特征最直接有效的手段。国内已有多家单位引进美国DMT公司的云粒子图像探头CIP。由于其配套软件不能输出逐个粒子的详细信息,在很大程度上限制了对云粒子图像探测数据的深入挖掘和分析。基于解析粒子图像原始数据,对粒子图像数据进行质量控制,并根据粒子形状几何特征将粒子形状分为8类(微小、线状、聚合状、霰状、球状、板状、枝状和不规则状)。利用2018年12月至2019年3月河南省3次冬季航测获取的灰度CIP探测数据,分析云粒子形状及各形状粒子面积的统计特征,并对比基于不同形状粒子的质量—尺度关系与将所有粒子视作球形液滴计算所得的粒子水凝物含量,发现后者超过前者约1个量级。(张荣, 李宏宇, 周旭, 李昊, 胡向峰, 夏强)

2.10 一次东北冷涡结构及云系特征分析

利用ERA5逐小时再分析资料、FY-4A卫星反演云特征参量产品、逐小时地面降水资料,分析了2020年5月16—19日一次东北冷涡降水过程的环流形势、热力不稳定条件、水汽输送及云系宏微观特征。结果显示,本次过程500 hPa低涡中心位于36°~48°N,对流层中高层至低层均有气旋性环流,伴随有地面气旋,属于深厚的中偏南涡,共维持了6 d。18日辽宁东部出现区域性暴雨,24 h降水量超过100 mm的站点有15个,最大雨强达到了43.4 mm/h,暴雨区出现在冷涡成熟阶段,位于冷涡后部偏北气流影响下,来自热带低压东侧西南低空急流输送的水汽与冷涡东南部的水汽输送合并,成为了暴雨产生的必要条件。降水强度大于6 mm/h的区域,K指数基本都大于35 ℃,且整层都有较强的垂直上升运动。冷涡云系云顶高度为4~9 km,靠近冷涡中心的涡旋状云系云光学厚度大于30,云层水凝物含量丰富密实,属于冷暖混合云,降水主要出现在这些区域;远离冷涡中心的区域云系光学厚度小于20,云层松散属于高层冰云,地面基本无降水。(史月琴, 周毓荃, 戴艳萍)

2.11 SPEC机载云探测系统及其云物理研究进展

在综合介绍我国机载云探测系统的发展历程、应用情况和优缺点的基础上,对新一代机载云探测系统SPEC的系统组成、探测原理、探测方法和探测范围等进行了详细说明,并探讨了近年来国内外相关研究进展。随着科学研究人员对云探测精细程度、准确度要求的日益提高,以往使用的粒子观测系统(PMS)等云探测系统已无法满足一些科学试验的需求;SPEC与很多其他云探测系统相比,在精密程度、探测粒子的信息量、分辨率等方面具有很大的探测优势,这对于云物理更深入的研究是非常重要的。国外研发并应用SPEC系统已有几十年的时间,而我国近年开始引进并越来越多地使用这套探测系统来探究云的宏微观物理特性,这必将使得对云物理的理解更加深入。(刘思瑶, 赵传峰, 周毓荃)

2.12 基于Ka波段云雷达的六盘山顶云特征分析

本文利用宁夏六盘山气象站2017年9月至2018 年8月的Ka波段云雷达观测资料,统计分析了六盘山顶不同云的出现频率及宏观特征。结果发现:六盘山顶云出现频率最高值出现在7月,为61%,最低值出现在12月,为26%;按云层数划分,六盘山顶出现的云主要以1层云、2层云及3层云为主,相对总云的月平均出现频率分别为68%~86%、14%~27%及0.4%~4.8%;按云底高度及云层厚度划分,六盘山顶低云、中云、高云及直展云相对总云的月平均出现频率分别为29%~53%、14%~58%、6%~22%及2%~20%。云底高度在冬春季节高于夏秋季节, 云顶高度在夏秋季节高于冬春季节,云层厚度在1.6~3.6 km 之间,年变化特征与云顶高度类似。整体来看,春、夏、秋季云厚在白天大于夜间,冬季云厚在夜间大于白天,其中夏、秋季云厚日变化特征较为明显。(田磊, 桑建人, 姚展予,常倬林, 舒志亮, 曹宁)

2.13 基于微波辐射计的宁夏六盘山西侧大气水汽变化特征

采用隆德气象站2 a德制微波辐射计与同期1 h降水量资料,利用统计法分析了六盘山脉西侧大气水汽含量以及云液态水含量的时间分布特征,并分析了92次不同降水性质、不同降水量级的降水个例,得到降水前跃增时间的变化特征。剔除降水背景结果统计表明:(1)六盘山西侧大气水汽含量和云液态水含量有明显的季节变化,其中夏季是大气水汽含量最多的季节,平均为23.44 mm,占年均水汽含量的47.7%。(2)大气水汽含量和云液态水含量日变化呈—谷—峰分布,春、夏、秋三季均在午后出现最大峰值,冬季在11:00出现峰值;大气水汽含量低值区春、夏、秋季出现在日出前后,冬季出现在22:00。(3)87.0%的降水个例在降水发生之前大气水汽含量都在12.00 mm以上,且其值随着降水的量级增大而增大。(4)降水前云液态水含量发生明显跃增现象,春、夏季表现强,根据降水性质及降水量级不同,降水前跃增时间也不同。研究结论对把握人影作业时机具有一定的参考价值。(林彤, 桑建人, 姚展予, 舒志亮, 田磊, 曹宁, 常倬林)

2.14 利用FY-4A卫星光学数据对中国近地面PM2.5浓度的估算和检验分析

对FY-4A卫星的气溶胶光学厚度(AOD)产品进行检验,并根据卫星相关观测资料,通过改进后的PMRS方法,反演得到中国近地面PM2.5质量浓度网格化分布。结果表明,FY-4A卫星反演不同站点AOD与地基观测网(AERONET)观测结果吻合较好,但存在一定的低估或高估现象,相关系数区间为0.54~0.87。将细粒子比(FMF)以0.4为界进行划分,FMF>0.4时,拟合结果较FMF≤0.4时更接近于AERONET观测结果;但FMF≤0.4时,卫星反演的AOD稳定性优于FMF>0.4时。通过引入AOD的大小,改进FMF>0.4时对细粒子柱状体积消光比(VEf)的估算算法,并通过改进后的PMRS方法对中国近地面PM2.5浓度进行逐时反演,其反演结果和地面观测结果相关较好,其中,乌鲁木齐、石家庄和徐州观测点的相关系数均高于0.7,但数值上仍存在高估或低估,误差结果由多种因素决定。空间分布中,卫星反演的中国2019年近地面PM2.5浓度月均值与近地面观测的结果有较好的对应关系,二者逐月演变趋势基本一致,基本可以反映出中国近地面大气细粒子的空间分布,特别是秋、冬季京津冀周边区域、汾渭平原等污染高值区均与地面观测对应较好。(江琪, 迎春, 王飞, 张天航, 何佳宝, 桂海林,张碧辉, 徐冉)

2.15 崇明东滩湿地与上海城市气候特征对比分析

基于2010—2019年崇明东滩湿地与同期的上海近海台站、崇明气象站及市区气象站的温度、湿度、降水观测资料,采用时间同步对比方法,分析了崇明东滩湿地与上海城市不同地区的气候特征。结果表明:东滩湿地由于其地理位置特殊,与上海其他台站比,日最高气温最低、春夏气温升幅最小,日最低气温接近或高于近海台站和崇明城镇的日最低气温,仅低于中心城区的日最低气温,湿地不易升温、也不易降温;由于东滩湿地下垫面性质及周围环境与城市其他台站的不同,没有城市热岛效应、阻碍效应引起的增雨,中雨以上降水概率明显小于其他各站的降水概率,暴雨概率及强降水次数比其他各站分别少68%~75%和70%~81%,表明东滩夏季雨日少于其他各站的雨日,但秋冬季雨日比其他各站多18%~40%,这也是东滩湿地总雨日多的主要原因;东滩湿地不但缩小昼夜温差还缩小昼夜湿差,尤其湿地能降低雨强,致使有雨日逐年平均相对湿度反而比上海其他各站的小。(贺芳芳, 毛卓成, 姚展予, 许建明, 彭丽)

2.16 临沂市区冬季大气污染物的特征解析

基于2018年冬季临沂市区4个国控环境空气自动监测子站的SO2、NO2、CO、O3、PM2.5和PM10小时浓度数据,研究了临沂市区大气污染物的特征。结果表明:PM2.5和PM10污染最为严重,其次是NO2和CO,而SO2和O3污染较轻;SO2、CO和O3空间差异显著,NO2、PM2.5和PM10空间差异不显著。日变化特征分析发现,SO2、CO和PM10呈双峰型,NO2呈单谷型,O3呈单峰型,PM2.5呈一峰二谷型分布。O3与其他大气污染物不同,清洁天空气质量较好,强太阳辐射会促进光化学反应生成更多O3。气团后向轨迹聚类分析结果显示,临沂市区冬季主要受近距离的气团输送影响,同时也受到来源于蒙古国的高空远距离沙尘输送影响。(王璐, 温天雪, 周旭, 刘旭)

2.17 全球云水量气候分布及变化趋势特征分析

采用20世纪再分析版本2c数据集的云水量逐月再分析数据,通过数理统计方法,分析了1960—2014年全球、海洋和陆地上空云水量的分布和变化特征及其与水汽通量的关系。结果表明:(1)全球云水量空间分布不均,海洋高于陆地且比例约为4﹕3,中低纬海洋、陆地上空云水量变化趋势分别为0.07 g/(m2·10a)和−0.04 g/(m2·10a),季节性差异主要体现于夏季在热带辐合带和南半球海洋高,冬季在北半球海洋和南半球陆地高。(2)对比六大洲发现,云水量最高的南美洲有最快增加趋势,为0.46 g/(m2·10a),同时云水量最低的非洲有最快降低趋势,为−0.59 g/(m2·10a)。(3)中低层整层水汽通量散度场的辐合、辐散区和云水量的高、低值区相对应,云水量与水汽通量散度变化呈负相关(相关系数为−0.44),负相关关系在赤道附近的低纬地区显著。本文揭示了在全球变暖背景下,大气中云水量分布和变化的时空格局,为模式参数化和未来气候预估提供参考。(程敬雅,游庆龙,蔡淼)

2.18 云解析人工影响天气数值模式的改进、初步试验和展望

基于WRF四维资料同化和预报技术,初步发展了针对我国西北地区云微物理和播云催化技术的云解析人工影响天气模式系统(CR-WMM)。该模式耦合并改进了中国气象科学院发展的微物理方案(CAMS-MP)和碘化银(AgI)催化方案,并实现基于大涡模拟(LES)模式的飞机、地面烟炉等播撒源及毗邻区域AgI粒子扩散的精细模拟方法。选取降水案例对CR-WMM资料同化功能、CAMS-MP微物理参数化和AgI的催化数值模拟方案进行测试和评估,验证了该系统的资料同化能力、微物理参数化和AgI催化数值模拟方案的可靠性。CR-WMM具备连续同化常规和加密气象观测,特别是针对云微物理过程的新型卫星、云雷达和人工影响天气外场作业飞机和基地的特殊观测能力,能生成全面、精确的云和降水热力、动力和微物理分析场,支撑云和降水过程及云催化技术的理论研究及优化人工播云方案辅助决策。并提出为达到这一目标,CR-WMM模式在未来5~10年应集中攻克的5个方面的科学难题。(刘玉宝, 丁秋冀, 史月琴, 方春刚, 段婧, 楼小凤, 李萍, 霍朝阳, 周永波, 王昊亮, 景晓琴, 王新, 陈添宇, 陈宝君, 李集明)

2.19 基于时域对象的网格降水预报的追踪诊断分析

检验和评估模式降水预报的时间和位置偏差对提高降水预报准确率有重要意义,而传统点对点的检验方法对此无能为力。基于2018年和2019年6—8月欧洲中期预报中心(ECMWF)降水预报资料,利用面向对象时域诊断分析工具(MTD),追踪模式降水预报对象的生命周期、初生、消散等预报表现。研究表明:(1)个例分析显示,时域诊断分析工具MTD能够很好的从三维降水场中提取降水对象,进而刻画降水对象的生命周期及开始结束时间,对客观描述降水对象的时间偏差具有独特的优势。(2)低阈值条件下模式预报能很好地描述降水对象的空间分布,不足在于观测降水对象较模式预报明显偏多;随着降水阈值增大,预报与观测降水对象的空间频次呈现出显著差异,表明模式对强降水的位置预报仍然需要改进。(3)采用最小卷积半径和降水阈值定义降水对象,观测和预报场中80%的降水对象生命周期小于15 h,且生命周期随着降水阈值和卷积半径的增大而减小。(4)三维对象追踪显示,预报对象的持续时间较观测偏短,移动速度较观测整体偏慢。(张宏芳,潘留杰,卢珊,巨晓璇,史月琴)

3 项目进展和观测试验

3 Project progress and observational experiments

3.1 云水资源评估研究与利用示范

云水资源评估研究与利用示范研究取得如下进展:(1)基于大气水循环过程和云物理过程及大气水分收支平衡方程,提出并完善云水资源及其11个组成量和12个特征量的概念和计算式。(2)构建多尺度三维云场诊断技术体系,建立并优化云水资源观测诊断和数值模拟两套定量估算方法,研发云水资源评估系统(V1.0),实现中国和全球近20年1°分辨率、全球近60年2.5°分辨率的云水资源诊断评估及华北示范区近5年3 km分辨率的云水资源数值精细评估,并开展对比验证。(3)利用近20年中国云水资源评估数据集,研究得到中国不同人工影响天气分区和关键典型水文流域(如黄河流域、淮河流域)的云水资源特征,利用3 km的数值评估结果,揭示华北区域的云水资源特性,利用全球云水资源评估数据集,研究得到全球云水资源的时空分布特征和变化规律。(4)在两个示范区建立并优化固定目标区云水资源开发技术体系,探索发展北方层状云飞机增雨和南方对流云地面增雨优化的方案设计及效果评估方法;建立空陆耦合云水资源开发利用全流程技术体系,攻关云水资源预报及开发效果预估等关键技术环节,并应用于重大活动保障。

3.2 人工影响天气技术集成综合科学试验与示范应用

人工影响天气技术集成综合科学试验与示范应用项目开展了3次华北多机联合观测,取得星—空—地联合观测数据集2套;完成一种浸润冻结机制冰核测量装置(FINDA)的搭建与应用,其试验结果与国际上其他学者的结论一致。梳理南方各种类型对流云个例21个;分析祁连山地形影响下的云降水演变特征与机理以及地形云降水微物理特征与降水机制,结果表明不同类型强降水的形成机制及物理量条件各有差异,地形对降水的影响效应也各不相同,揭示地形云凝华和聚并是冰相层冰雪晶的增长机制,混合层冰晶增长以贝吉龙过程为主,并伴有淞附和聚并生长;利用DBSCAN聚类算法及Hough变换,提出一种对雷达线状或带状飑线的自动识别方法,并用5次飑线天气过程检验DBSCAN算法和Hough变换的合理性和有效性;初步试验结果认为燃气炮增雨作业有效果,但还需要开展更多的外场试验和试验分析。基于飞机观测检验微物理结构模拟,将各微物理方案模拟的IWC、冰相粒子谱、粒子数浓度和M-D关系进行了对比分析,给出各微物理方案在模拟能力上的各自优势。

3.3 新一代人工影响天气数值模式系统研发

新一代人工影响天气数值模式系统研发工作取得如下进展:(1)在WRF中建立全新三参数云物理方案并开展批量预报试验,对6月份一个月的预报结果表明,该方案可以有效预报不同云降水过程,在模式积分时间步长方面有待改进。(2)在WRF4.2动力框架中耦合了CAMS双参数云微物理方案,利用1 km水平分辨率开展不同区域、不同时间的积层混合云、对流云、层状云等多个例模拟研究,模式运行稳定,模拟的降水、云系结构特征及演变与卫星、雷达、机载云物理探测实况相符。(3)开展AgI催化方案的编制及与WRF模式中CAMS云方案的耦合试验。(4)采用分析逼近Nudging同化方法,开发雷达资料反演的水成物场及对应的潜热进行同化的方案,基于WRF模式实现对雷达资料的实时同化和模拟应用,个例对比试验表明,同化后对于模拟的降水落区范围比无同化有明显改善,更接近实况观测。(5)探索了面向对象检验(MODE)方法在云场检验方面的适用性,开展了不同检验方案(格点、邻域、对象)对预报云场的检验适用性研究,并对夏季的云场预报结果进行检验应用。

3.4 新型催化剂研发

组织召开新型催化剂研制课题2021年度工作会议,课题组开展了膨胀云室物理模拟试验能力的测试和初步试验,进一步完善云室系统的云雾参数监测系统;开展了表明活性物质作为暖云催化潜力的模拟试验;开展了华北污染背景的实验室模拟试验研究(70 m3膨胀云室);开展了纳米催化剂的扩散云室模拟试验研究;讨论研制了3中不同吸湿性暖云催化剂的试验配方,完成工厂加工压制和工厂性能测试,近期将送北京实验室开展模拟试验,进而筛选出效果较好的暖云催化剂型。完成发表论文1篇,申请发明技术专利1项,已进入实质性审查阶段,申报实用新型技术专利3项,其中2项得到授权,1项受理中。1项气象行业标准预研究项目通过验收。

3.5 贵州防雹外场观测试验

2021年4月,首部用于人工防雹观测的X波段双偏振相控阵雷达在贵州威宁防雹基地建成。2021年5月13日,人工影响天气中心组织开展国家(贵州)防雹外场科学试验实施方案论证会。5月27日召开2021年国家(贵州)防雹外场试验启动会,人工防雹外场试验正式启动。试验持续到9月底结束,基于X波段双偏振相控阵雷达共观测防雹个例18次,收集了多种扫描方式(体扫、扇扫和RHI扫)的防雹观测资料,为贵州威宁冰雹结构特征分析和防雹效果检验提供了直接的外场观测资料,目前正对观测资料进行整理分析。本次观测通过利用高时空分辨率的相控阵雷达资料清楚观测到贵州威宁冰雹云的发展演变过程和垂直结构特征,发现威宁冰雹发展迅速,稳定少动;雹云强回波首先出现在空中,然后向下发展加强;雹云在成熟期主要呈倾斜垂直结构,有明显的有界弱回波区,空中存在冰雹特征。高时间分辨率的相控阵雷达能对防雹效果进行检验,从相控阵雷达可以看到高炮作业后强对流的雷达回波减弱、强回波面积有所减少,特别是高炮作业量增大后,防雹作业效果比较明显。

3.6 庐山云雾降水外场观测试验

2021年,对庐山云雾降水外场观测试验进行了重新部署,开展了秋冬季外场试验。在2020年外场试验方案的基础上,根据新设备补充情况和2021年的试验需求,不断完善试验方案和实施方案,编写完成了《2021年国家(庐山)云雾物理试验基地外场观测试验方案》。2021年9月28—29日联合江西省气象局组织和召开了2021年国家(庐山)云雾物理试验基地外场观测试验启动会,秋冬季外场观测试验正式启动。会后与江西省气象局联合编写完成《庐山云雾物理试验基地2021年外场试验工作方案》,作为工作指南。此次试验布局为以山上、山下的联合梯度观测,以及山上不同地点的同要素对比观测,依此开展包括秋冬季大气与气溶胶背景特征、云宏观及微物理特征研究。根据观测要求,新增2台雾滴谱仪、冰核采样器、云凝结核仪、PCASP-X2、雾水采集器等观测设备,并将云雾站单一的观测点扩展到云雾站和仰天坪两个观测点,在仰天坪调度和布设了自动气象站、雾滴谱仪、能见度仪、微雨雷达、云凝结核仪、冰核采样器和颗粒物仪等观测设备。2022年1月9日,庐山秋冬外场试验基本完成年度观测任务(10月1日至1月9日)。此次试验10月初开始,11月10日基本完成两个主要观测点(云雾站、仰天坪)的设备调试和部署,12月8日完成梯度观测部署(庐山市气象局),所有设备部署地点均按试验方案部署完成后,一直进行持续的加强观测。初步统计,捕捉重点天气过程约13次,包括云雾(最多)、降雨(1次)、降雪(3次)、冻雨(1次)过程。采集包括雾滴谱仪、微雨雷达、微波辐射计、云高仪、能见度仪、云凝结核计数器、颗粒物仪、自动站等数据资料约670 G;雾水样本(46份);冰核膜采样样本(95份)。在山上两个站点(仰天坪和云雾站)重点开展了云雾、降水对比观测;此外,在仰天坪开展了冰核、云凝结核加强观测,在云雾站开展了云雾过程的雾水采集观测;同时实现了山上、山下云宏观特征的梯度对比观测。获取了多次包括冻雨等特殊天气过程的观测数据。

3.7 数据集建设

庐山云雾观测数据集建设进展。4月邀请参与过庐山观测的老专家协助解决历史数据中字迹不清楚和记录方法等问题,重新翻阅了纸质版历史资料,经过4个版本的更新,已经完成历史数据集的数字化工作。7月初经商议确定现代数据集除了csv文本格式,新增NetCDF格式数据集,确定了NetCDF格式确定数据录入信息和结构存储方式。9月在针对nc格式的专家咨询会中进一步确定了存储的细节并咨询疑问,已经完成两个版本的csv格式和NetCDF格式的数据样本。合理利用人影数据标准编码规范的同时,调整了地基特种观测数据的编码格式,改进和更新了数据集的存储和质控方案。经过一年多的建设,目前对于历史观测资料,已经完成所有资料的归整、查阅、补充扫描、内容订正等工作,完成了历史数据集的数字化。对于现代观测数据,已经完成数据的质量控制,并多次完善现代数据的编码和存储方案,阶段性的推进数据集建设,形成现代数据集样本,并正在开展数据质量评估。庐山云雾观测数据集已基本建成。同时,建设期间初步形成了一套较完整的《人工影响天气试验地面特种观测资料集数据文件编码和存储格式规范(草稿)》。

飞机观测数据集建设进展。优化改进了飞机数据处理系统,完成国家级飞机探测数据集建设项目的平台改造;初步建立了一套飞机数据集,完成2017—2020年国家级高性能飞机所得探测数据的处理和成集工作,并提供中心使用;梳理了一批典型探测个例,初步形成了一套飞机数据质控流程,为中心所承担的重大活动保障、重要应急保障以及重点科研项目所得的飞机探测数据提供质控和产品制作服务;完成了用户手册、工作报告、技术报告等文档。

3.8 云雾物理环境重点开放实验室开放课题

2021年度中国气象局云雾物理环境重点开放实验室开放课题分别在多源数据融合技术的人工影响天气应用研究、冰雹云结构及成雹机理研究、山地环境气溶胶—云雾特征及相互作用研究,以及人工增雨防雹火箭技术研究5个重点研究领域共资助11个课题,资助强度2~3万元,总经费26万元。受资助人员涵括人影业务部门、相关高校以及科研单位。

4 人工影响天气现代化建设

4 Modernization of weather modification

4.1 西北区域人工影响天气能力建设项目总体设计与实施

概要梳理了西北区域人工影响天气能力建设项目总体设计的思路,归纳了设计中所重点考虑的3个技术系统和技术措施,总结了项目建设模式与经验,可为后续区域人工影响天气项目建设提供参考和借鉴。(李集明,陈添宇,陈宝君,顾青峰,殷占福,段婧,李宏宇,李德泉,方春刚,房文,尹宪志,李林,桑建人, 李抗抗)

4.2 “云+端”业务框架的西北人工影响天气指挥应用系统综述

简要阐述了面向人工影响天气业务深度融入“天擎”大数据云平台需求,在西北区域首先采用“云+端”业务系统架构模式设计并实现新型的人工影响天气指挥业务系统(SPACE-NW),为人工影响天气各类业务提供综合业务软件支撑。该系统依托“天擎”基础,提出具有普适性的人工影响天气“云+端”下的“4C+ABC”框架,实现了人工影响天气业务数据环境深度融入、产品分析与自动化制作与加工流水线的深度融入、资料分析与指挥业务流程与基础气象业务的深度融入。解决了人工影响天气部门一段时期以来的资料采集渠道多样、标准不统一、系统开放性不足、信息流转渠道不畅等业务问题。该系统在西北区域率先部署试用,发挥省级人工影响天气业务与“天擎”的深度融入的典型示范作用。(李德泉,李集明,田建兵,田显,穆建华,李宝梓 ,白向东,李圆圆)

4.3 西北区域人工影响天气试验示范基地设计

西北人工影响天气工程在西北地区选取重点区域建设人工影响天气试验示范基地,合理设计观测仪器设备布局,建立了涵盖中尺度水汽、风场监测、云降水宏观场监测、云降水微观场探测的大气、云和降水宏微观三维结构及湿热力、动力综合监测网;在基地科学设计外场试验区,开展外场作业试验,开展新型催化作业装备和催化剂研发。基地的建设能够有效地促进我国人工影响天气业务自主创新,为西北区域和全国人工影响天气业务发展提供有力的科技支撑,提高作业效率和水平,提高西北区域人工影响天气作业实际效益。目前该基地已基本完成观测系统以及业务平台建设,观测资料已在研究试验中得到有效应用。(方春刚, 段婧, 李圆圆, 李宝梓, 岳治国, 田磊, 田建兵, 黄山, 陈添宇, 陈宝君, 李集明)

4.4 西北人工影响天气工程研究试验设计与实施

西北区域人工影响天气能力建设项目通过科学设计,创新运行机制,预期利用已有和本项目即将建设的装备设施,通过有科学设计的专项研究,开展针对西北区域地形云的人工增雨(雪)试验研究。在工程项目建设中设立研究试验内容,旨在通过项目建设中同步实施试验研究,充分体现科技支撑能力在工程项目中的重要作用。本文总结了西北区域人工影响天气能力建设项目中研究试验的设计和实施过程,依据建设经验,提出提高工程项目效益的建议,为相关工程项目建设提供参考。(段婧,王自强,李圆圆,程鹏,常倬林,林春英,岳治国,史金丽,殷占福,陈宝君,陈添宇,李集明)

4.5 空中国王350增雨飞机改装与集成设计

介绍了西北区域人工影响天气能力建设项目(以下简称“西北人影项目”)建设的2架空中国王350国家级作业飞机(以下简称“西北空中国王飞机”)差异化和通用化的设计思路,以及西北空中国王飞机机载大气探测系统、机载催化作业系统、空地通信系统改装集成工作的所要遵循的原则、工作思路和初步方案。对后续人工影响天气区域工程项目飞机改装集成工作提供相应的技术支持。(高扬,李宏宇,殷占福,戴艳萍,陈添宇,李集明)

4.6 新舟60高性能增雨飞机机载任务系统集成设计

西北区域人工影响天气能力建设项目设计建设的新舟60增雨飞机是集催化作业、云宏微观探测以及实时通信与综合集成显示功能于一体的国家高性能人工增雨飞机,该飞机系统建设中充分汲取了前期东北区域国家增雨飞机研制成果与经验,并在系统供电管理、催化作业能力、探测系统集成、卫星通信功能、设备系统和操作台布局等方面进行了针对性设计改进,通过便捷操作实现对任务系统供电与各分系统的集中控制、综合显示、数据存储共享,并且机载探测、催化、通信各分系统均采用双重或多重备份设计,既保证了机载任务系统先进性设计,同时保证任务系统运行稳定可靠和各项功能的完整实现。(张骁拓,胡颖琼,李宏宇,苏海周,周旭,高扬,张荣)

4.7 陕西渭北果业区冰雹研究进展

阐述了开展陕西渭北果业区防雹技术研究试验的重要意义,讨论了渭北果业区冰雹研究在气候、雷达回波、雹云探空、冰雹微物理、数值模拟和防雹效果等方面的进展,并对研究试验中存在的问题进行了讨论。这些研究加深了渭北冰雹形成过程的认识,对研究高效冰雹防御方法和提高冰雹防御效果有重要意义。(岳治国,陈宝君,王瑾,左爱文,李金辉,罗俊颉,朱荣增,花少烽,刘佩佩)

5 人工影响天气重大应急与重大服务保障

5 Weather modification in support of major emergency response and major event service

面对持续时间长、影响范围广的南方冬春连旱,迅速响应、国省协同、空地联合作业,全力做好抗旱增雨、森林灭火等重大应急服务保障。在日常业务发布的人工影响天气模式预报和卫星监测云条件产品基础上,针对重大活动保障和森林草原防灭火等应急人工影响天气服务保障,完善潜力预报和预案制定、条件监测和方案设计、信息收集与效果评估等全流程的6类人工影响天气专项服务指导产品,并在河南、西藏林火等重大应急和重大活动服务保障中开展应用。

采用新技术、利用新资料,老中青同心聚力完成各项重大人工影响天气专项保障服务。全年发布7种服务材料共245期,专题会商56次,2期决策服务材料报送党中央,1期获得中央领导同志的批示。积极参与国产大飞机试飞气象保障工作。与商飞密切配合,利用进博会增雨作业飞行,开展自然结冰探测。与中航工业试飞院签订关于大飞机自然结冰项目战略合作框架协议书。

6 研究型人工影响天气业务发展

6 Reseach-oriented development of weather modification operations

6.1 指挥业务精细化发展

开展精细化云预报试验。将人工影响天气业务模式水平分辨率从3 km提高至1 km并开展试用,云水资源预报在重大服务中应用。改进人工影响天气催化模式,利用WRF-AgI催化模式和对流云-AgI催化模式,实现飞机、火箭等人工增雨、消减雨和消雹催化的仿真模拟,进行了不同催化模式的催化效果比较研究。

提升国家级业务平台功能和业务支撑能力。2021年7月1日,全国人工影响天气综合信息系统正式投入业务运行,该系统整合原有“人工影响天气作业信息采集处理系统”和“人工影响天气业务产品共享发布系统”,实现产品发布、信息上报、实时监控、业务管理和通知通报等功能。“人工影响天气综合信息系统”面向全国业务运行有效提升了人工影响天气指导产品发布的时效性和作业信息采集的规范性。

开展国家级人工影响天气核心业务系统融入“气象大数据云平台”工作。对各个业务系统账户进行了进一步的规范化管理,完善了系统的融入方案和实施进程。国家级人工影响天气平台已基本实现了从CIMISS平台过渡到云平台进行实时业务数据的采集。

6.2 人工影响天气装备安全运行

联合有关省组建国家级飞机运行技术支持团队,为国家飞机安全高效运行提供技术支持。对新疆、陕西国家飞机托管招标文件进行技术审查,把严把牢安全运行红线。对国家飞机设备系统状态及运行开展安全巡检。

配合完成“3·1”事故处理。调研编制飞机安全运行及管理模式等的决策服务材料。推进相关标准规范建设,编制《人工影响天气飞机安全检查规范(试行)》《国家人工影响天气飞机作业规程(试行)》和《国家人工影响天气飞机航材库管理办法(试行)》等3项业务规范并经减灾司印发全国执行。

完成人工影响天气弹药物联网系统运行监控和作业装备行政审批技术审核。配合减灾司做好安全生产督查工作,编制安全检查报告。

6.3 国内外交流合作

推进中泰、中韩、中阿、中沙在人工影响天气领域的合作。(1)中泰合作:2021年2月9日,通过线上视频会议的形式与泰国签署了人工影响天气技术合作协议。中泰双方在2021年7月29日以线上的形式召开了技术交流讨论会,进一步细化了双方的合作计划。(2)中韩交流:中国气象局人工影响天气中心与韩国国立气象科学院于2021年12月30日举办了2021年中韩人工影响天气技术视频交流会。双方主要讨论了人工增雨效果检验相关问题(包括对比区的选取、增加雨量的计算、增雨作业的时效性等)、冰核观测及设备相关情况,以及未来双方可以开展的合作。(3)中阿交流:2021年4月12日,中国气象局和阿联酋国家气象中心人工影响天气专家14人举行视频会议,交流人工影响天气技术研究和业务工作进展,研讨未来合作意向。(4)中沙交流:应沙特阿拉伯方面要求对其关心的我国人工影响天气领域的几个方面内容进行答复。明确了中沙合作的联系人。

组织筹办12期云雾物理开放实验室学术交流论坛,出版《全国人工影响天气技术与方法交流会论文集(2020)》《气象科技进展》西北人工影响天气专刊(2021年11月)。

参加气象科技活动周、全国林业和草原科技活动周、第18届中国—东盟博览会、国家“十三五”科技创新成就展,人工冰晶模拟系统获得2021年气象科技活动周优秀展项奖。人工影响天气中心援疆专家在政府部门开展科普讲座,使得人工影响天气工作被更多人了解和认识,取得了良好的社会反响。

6.5 人工影响天气标委会工作

积极推进项目申报和标准的编制进度。新颁布行业标准2项,国家标准1项;批复国标立项1项,国标外文版立项1项,行标7项,行标预研究1项;推荐申请国标1项;组织完成标准预审9次、正式审查10次,函审6次;组织开展标准网上征求意见工作5项。组织完成1项国标的网上立项投票。编辑印制了2003—2020年度人工影响天气领域标准文集。

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