Atmospheric Research最新文献_第8页

Spatial and temporal variation of raindrop size distribution in Great Britain 英国雨滴大小分布的时空变化

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-11 DOI: 10.1016/j.atmosres.2025.108699

Shan Jiang , Dawei Han , Rafael Rosolem , Merhala Thurai , Miguel A. Rico-Ramirez

Raindrop size distributions (DSDs) play a key role in revealing the underlying physical processes of rainfall. This study investigates the characteristics of the DSDs in Great Britain (GB) using data collected from eleven Thies laser precipitation monitors (LPMs) between 2017 and 2019. Around one million one-minute raindrop samples were fitted to a normalized gamma drop distribution model. This study examines the DSD characteristics from both temporal (seasons) and spatial (geography and topography) perspectives, considering different rain types (stratiform and convective) and rain rate clusters. The results indicate that the average mass-weighted mean diameter

(D_{m})

and the average normalized intercept parameter

\log_{10} (N_{w})

are influenced by geographical and atmospheric conditions. The

(D_{m})

tends to be lower and

\log_{10} (N_{w})

is higher in the western and hilly regions, with the opposite pattern observed over the eastern plain of GB. Both parameters are strongly correlated with rain rate. Compared to subtropical/tropical regions, stratiform rain in GB exhibits smaller

(D_{m})

and larger

\log_{10} (N_{w})

, while the characteristics of convective rain align with the maritime-like cluster. Significant differences in

(D_{m})

are observed between stratiform (0.78–1.00 mm) and convective (1.30–1.74 mm) rain, with both showing a significant negative linear correlation with

\log_{10} (N_{w})

. Moreover, extreme convective events show distinct seasonality, with larger

D_{m}

and lower

\log_{10} (N_{w})

during the warm season. Furthermore, a bimodal distribution is observed for

\log_{10} (N_{w})

in light rain events over western and hilly regions, highlighting the complexity of microphysical processes associated with small raindrops. The characteristics of DSDs observed in this study provide valuable insights for future investigations into GB's precipitation formation and quantitative precipitation estimation using weather radar.

雨滴大小分布（DSDs）在揭示降雨的潜在物理过程中起着关键作用。本研究利用2017年至2019年11台Thies激光降水监测仪（lpm）收集的数据，调查了英国（GB）的dsd特征。大约一百万个一分钟的雨滴样本被拟合到标准化的伽马雨滴分布模型中。本研究从时间（季节）和空间（地理和地形）两个角度考察了DSD特征，考虑了不同的降雨类型（层状雨和对流雨）和雨率簇。结果表明，平均质量加权平均直径Dm和平均归一化截距参数log10Nw受地理和大气条件的影响。西部丘陵区Dm偏小，log10Nw偏大，东部平原则相反。这两个参数都与降雨率密切相关。与亚热带/热带地区相比，中国的层状雨Dm较小，log10Nw较大，对流雨的特征与海洋状星团一致。在层状雨（0.78-1.00 mm）和对流雨（1.30-1.74 mm）之间观察到Dm的显著差异，两者都与log10Nw呈显著的负线性相关。极端对流事件具有明显的季节性特征，暖季Dm较大，log10Nw较小。此外，在西部和丘陵地区的小雨事件中，观测到log10Nw的双峰分布，突出了与小雨滴相关的微物理过程的复杂性。本研究观测到的sdds特征为今后研究中国降水形成和利用气象雷达定量估算降水提供了有价值的参考。

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引用次数: 0

Estimating the full-day planetary boundary layer height from lidar, AMDAR, and radiosonde observations over Beijing, China 从中国北京上空的激光雷达、AMDAR和无线电探空观测估计全天行星边界高度

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-11 DOI: 10.1016/j.atmosres.2025.108701

Jieyu Hou , Mengyao Li , Guicai Ning , Tianwen Wei , Jinlong Yuan , Haiyun Xia

The planetary boundary layer (PBL) is the core transition zone for mass, energy, and momentum exchanges between surface and free atmosphere, significantly modulating weather, climate and human activities. However, full-day evolutions of PBL structure and PBL height (PBLH) remain limited as insufficient atmospheric vertical observations. Here, we comprehensively evaluate PBL features and PBLH detected from radiosonde, AMDAR, and lidar over Beijing, China. The PBL detections from the three platforms are significantly consistent, confirming their collective efficacy in full-day PBL monitoring. Notably, some outlies with obvious discrepancies in PBLH detection among these three platforms are extracted and their underlying causes are revealed. Then, these outliers are removed and the consistency in PBLH detected from the three platforms markedly improved. The correlation coefficient (R) and the root mean square error (RMSE) in PBLH detected from radiosonde and AMDAR range from 0.44 to 0.64 and 207.02 m to 264.85 m, respectively. PBLH detected from radiosonde (AMDAR) and lidar under stable (convective) and neutral thermal conditions significantly correlates at R ranging from 0.53 (0.67) to 0.67 (0.73) and RMSE from 218.77 m (324.77 m) to 304.23 m (386.57 m). Moreover, PBLH detections from all three platforms consistently show that convective PBLH > neutral PBLH > stable PBLH. These results highlight the reliability of aircrafts' and lidar's observations in detecting PBLH and PBL thermal structures. Finally, PBL detections from the three platforms are integrated to monitor full-day PBL, compensating for the radiosonde's limitation in monitoring convective boundary layer.

行星边界层（PBL）是地表与自由大气之间质量、能量和动量交换的核心过渡区，对天气、气候和人类活动具有重要的调节作用。然而，由于大气垂直观测不足，PBL结构和PBL高度（PBLH）的全天演变仍然有限。在这里，我们综合评估了中国北京上空从无线电探空仪、AMDAR和激光雷达探测到的PBL特征和PBLH。三个平台的PBL检测结果非常一致，证实了它们在全天PBL监测中的集体功效。值得注意的是，我们提取了三个平台之间PBLH检测差异明显的离群点，并揭示了其根本原因。然后，将这些异常值去除，从三个平台检测到的PBLH的一致性显着提高。探空和AMDAR测得的PBLH相关系数R和均方根误差RMSE分别在0.44 ~ 0.64和207.02 ~ 264.85 m之间。在稳定（对流）和中性热条件下，无线电探测（AMDAR）和激光雷达探测到的PBLH在R范围为0.53 (0.67)~ 0.67 (0.73)，RMSE范围为218.77 m (324.77 m) ~ 304.23 m （386.57 m）之间显著相关。此外，三个平台的PBLH检测一致显示对流PBLH >；中性PBLH >；稳定PBLH。这些结果强调了飞机和激光雷达观测在探测PBLH和PBL热结构方面的可靠性。最后，将三个平台的PBL检测集成到全天监测PBL，以补偿无线电探空仪在监测对流边界层方面的局限性。

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引用次数: 0

Summertime characteristics and in-situ photochemistry of volatile organic compounds in a high-altitude region in central China: Implications of regional transport 中国中部高海拔地区挥发性有机物的夏季特征和原位光化学：区域运输的意义

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-10 DOI: 10.1016/j.atmosres.2025.108692

Zhaoqi Wang , Chunmian Yang , Haibin Huang , Mengjie Deng , Jiapeng Ran , Xiaoxiao Li , Xiaofen Pei , Han Yue , Hairong Cheng

The chemical characteristics and photochemistry of volatile organic compounds (VOCs) were investigated at Shennongjia (SNJ), a high-altitude site in central China, from July to August 2023. The mean mixing ratio of total VOCs (TVOCs) was 14.61 ± 1.64 ppbv, dominated by alkanes (35.4 %) and carbonyls (29.4 %). The northeastern air mass exhibited the highest VOC concentration (16.33 ± 7.62 ppbv), followed by the southeastern air mass (10.45 ± 3.25 ppbv). Analysis of potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) identified central/eastern Hubei and the Sichuan Basin as major source regions for VOCs at SNJ. An observation-based photochemical box model was employed to examine VOC photochemistry and in-situ O₃ formation. Extremely low nitric oxide (NO) mixing ratios led to incomplete HOx cycling, and VOCs actively participated in the generation of free radicals. In-situ O₃ formation was governed by regionally transported air masses with distinct VOC compositions. Northwestern air masses, characterized by high temperature, high carbonyls, and low relative humidity (RH) despite lower TVOCs (8.10 ± 1.29 ppbv), yielded the highest net O₃ production rate (1.27 ± 0.33 ppbv/h), with formaldehyde photolysis contributing 13.3 % to hydroperoxyl radical (HO₂) generation. Conversely, the southeastern air masses, despite carrying the highest TVOC load, inhibited O₃ formation due to elevated RH. Formaldehyde and isoprene dominated photochemical reactivity. Our results highlight that VOC speciation, especially reactive carbonyls and biogenic VOCs, critically controls radical cycling and O₃ dynamics in remote regions.

于2023年7 - 8月在中国中部高海拔地区神农架（SNJ）对挥发性有机物（VOCs）的化学特征和光化学特征进行了研究。总挥发性有机化合物（TVOCs）的平均混合比为14.61±1.64 ppbv，以烷烃（35.4%）和羰基（29.4%）为主。东北气团VOC浓度最高（16.33±7.62 ppbv），东南气团次之（10.45±3.25 ppbv）。潜在源贡献函数（PSCF）和浓度加权轨迹（CWT）分析表明，湖北中东部和四川盆地是SNJ地区VOCs的主要源区。采用基于观测的光化学箱模型来检测VOC光化学和原位O3形成。极低的NO混合比例导致HOx循环不完全，VOCs积极参与自由基的生成。原位O₃的形成受具有不同VOC成分的区域输送气团的控制。西北气团温度高、羰基含量高、相对湿度低，但TVOCs较低（8.10±1.29 ppbv），净产O3率最高（1.27±0.33 ppbv/h），甲醛光解作用对羟基自由基（HO2）的生成贡献率为13.3%。相反，东南气团尽管携带最高的TVOC负荷，但由于RH升高，抑制了O3的形成。甲醛和异戊二烯主导光化学反应。我们的研究结果表明，VOC的形成，特别是活性羰基和生物源性VOCs，对偏远地区的自由基循环和O3动力学起着关键的控制作用。

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引用次数: 0

Revealing ozone formation mechanisms driven by VOCs and meteorology using interpretable machine learning 利用可解释机器学习揭示由挥发性有机化合物和气象学驱动的臭氧形成机制

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-10 DOI: 10.1016/j.atmosres.2025.108693

Lingling Lv , Peng Xu , Zishuo Xu , Yangxi Chu , Peng Wei , Xiao Liu , Jingnan Hu

Ozone (O₃) pollution in urban environments arises from complex photochemical interactions among volatile organic compounds (VOCs) and meteorological factors, yet the nonlinear and synergistic effects remain poorly constrained. Existing studies have identified key roles of humidity, temperature, and emission precursors, but how their interactions regulate O₃ production under varying conditions is less understood. Here, we applied machine learning with Shapley additive explanations (SHAP) to disentangle the contributions of chemical precursors and meteorological factors on O₃ formation in Huzhou, using continuous monitoring data from May to October 2023. Meteorological drivers accounted for 47.1 % of the total impact, with relative humidity (RH) and temperature (T) dominating. RH above 70 % consistently inhibited O₃ production and attenuated temperature effects. Chemical precursors contributed 52.9 %; within the chemical contribution, OVOCs (27.7 %) promoting O₃, while NO₂ (25.9 %) and alkenes (15.8 %) exhibited negative effects. The positive role of OVOCs diminished under high-NO_x conditions due to constrained radical propagation. During O₃ pollution episodes, meteorological influence increased by 15 % relative to clean periods, primarily via RH, while VOCs contributions declined and NO₂ effects strengthened, indicating a shift in the dominant O₃ drivers. Combining SHAP attribution with theoretical calculations identified propylene, styrene, and acetone as key VOC species. Propylene and styrene exhibited negative effects on O₃ formation, with styrene's suppression intensified under elevated NO₂ and RH, whereas acetone enhanced O₃ particularly under higher T. These findings highlight the dynamic chemical-meteorological interactions shaping O₃ production and provide a framework for rapidly diagnosing local O₃ drivers to inform targeted mitigation strategies.

城市环境臭氧（O3）污染是由挥发性有机化合物（VOCs）与气象因子之间复杂的光化学相互作用引起的，但其非线性和协同效应尚未得到充分的约束。现有的研究已经确定了湿度、温度和排放前体的关键作用，但它们之间的相互作用如何在不同条件下调节O3的产生尚不清楚。利用2023年5 - 10月的连续监测数据，利用机器学习和Shapley加性解释（SHAP）分析了化学前体和气象因子对湖州O3形成的贡献。气象因素占总影响的47.1%，以相对湿度（RH）和温度(T)为主。70%以上的相对湿度持续抑制O3的产生，并减弱温度效应。化学前体占52.9%；在化学贡献中，OVOCs（27.7%）对O3有促进作用，而NO2（25.9%）和烯烃（15.8%）对O3有负面影响。在高nox条件下，由于自由基传播受限，OVOCs的积极作用减弱。在O3污染事件期间，气象影响相对于清洁期增加了15%，主要通过RH，而VOCs贡献减少，NO2效应增强，表明主导O3驱动因素发生了转变。将SHAP归因与理论计算相结合，确定丙烯、苯乙烯和丙酮为主要挥发性有机化合物。丙烯和苯乙烯对O3的形成有负面影响，在NO2和RH升高的情况下，苯乙烯对O3的抑制作用加剧，而丙酮对O3的抑制作用在t升高的情况下尤为明显。这些发现突出了影响O3生成的动态化学-气象相互作用，并为快速诊断当地O3驱动因素提供了一个框架，从而为有针对性的缓解策略提供信息。

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引用次数: 0

Evaluation of the effectiveness of the large turbulent eddies parameterization in typhoon for typhoon intensity forecasting 台风大湍流涡参数化对台风强度预报的有效性评价

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-10 DOI: 10.1016/j.atmosres.2025.108690

Xin Li , Ying Li , Zhiqiu Gao

Previous observation verified that large turbulent eddies (LEs) prevail in the tropical cyclones and significantly affect the vertical mixing in the planetary boundary layer. Recently, Li and Pu (2021) had parameterized the vertical eddy diffusivity (VED) associated with LEs (LP scheme). To further investigate their rationality, we conducted 79 sensitivity simulations of Super Typhoon Lekima (2019) through WRF model to examine the critical processes in LP scheme. The simulation indicates that the weak convergence flow lead to LEs covers more in the inflow region. Subsequently, strong negative momentum flux associated with LEs disrupts the inflow structure, resulting in a poor typhoon simulation. Adding a moderate divergence and Ri threshold, i.e., LED03-RI30, could suppress the excessive vertical mixing in the inflow region to ensure the typhoon intensification and lead to an intense typhoon as observed. Reducing the scale factor of LE intensity in LP scheme also result in stronger typhoon, however, it delays the intensification of typhoon. The use of planetary boundary layer height, fixed height, or height scaling can potentially improve the

H_{m}

(the height of maximum LE intensity) calculation and thus optimal LE parameterization. However, due to the gradient wind balance, the enhanced wind speed induced by the LE parameterization tends to result in a lower sea-level pressure than the best-track. Validation simulations of Typhoon Hato (2017) and Maria (2018) show a weak effect of LP scheme. Although VED has been enhanced, the vertical velocity gradient in typhoon Hato and Maria are weaker, making the flux, which is associated with LEs, is weaker than that in Typhoon Lekima. Therefore, the vertical structure should be taken into account in the LE parameterization such as LP scheme.

以往的观测证实，在热带气旋中普遍存在大型湍流涡旋，并对行星边界层的垂直混合有显著影响。最近，Li和Pu（2021）已经参数化了与LEs相关的垂直涡扩散率（VED）（LP方案）。为了进一步探讨其合理性，我们利用WRF模型对超级台风利奇马（2019）进行了79次敏感性模拟，以检验LP方案中的关键过程。模拟结果表明，弱辐合流导致入流区LEs覆盖增加。随后，与低气压相关的强负动量通量破坏了入流结构，导致台风模拟效果不佳。增加一个中等辐散和Ri阈值，即LED03-RI30，可以抑制入流区过度的垂直混合，保证台风的增强，从而形成观测到的强台风。降低LP方案中LE强度的尺度因子也会使台风变强，但会延缓台风的增强。使用行星边界层高度、固定高度或高度缩放可以潜在地改进Hm（最大LE强度高度）计算，从而优化LE参数化。然而，由于梯度风平衡，LE参数化引起的风速增强往往导致海平面气压低于最佳路径。台风天鸽（2017）和台风玛丽亚（2018）的验证模拟显示LP方案的效果较弱。台风“天鸽”和台风“玛利亚”的垂直速度梯度虽然有所增强，但相对较弱，使得与“天鸽”相关的通量弱于台风“利基马”。因此，在LP方案等LE参数化中应考虑到垂直结构。

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引用次数: 0

Impacts of Climate Change on Tropical Cyclones and associated Rainfall over South Korea: Storyline and Risk-based approaches 气候变化对韩国热带气旋和相关降雨的影响：故事线和基于风险的方法

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-09 DOI: 10.1016/j.atmosres.2025.108685

Yusuke Hiraga , Jose Angelo Hokson , Bomi Kim , Yaewon Lee , Seong Jin Noh

The western North Pacific region has experienced Tropical Cyclones (TCs)-caused damages, including the heavy rainfall disaster brought by Typhoon Hinnamnor (2022) in South Korea. The future changes in the intensity and frequency of such a Violent Typhoon and its associated rainfall are global concern. This study adopted the storyline approach using the Pseudo-Global Warming (PGW) method to quantify the impact of climate change on Typhoon Hinnamnor and its associated rainfall. Furthermore, we employed the risk-based approach to examine the changes in frequency and intensity of TCs affecting South Korea. Our storyline approach showed the increase of maximum sustained wind speed by 15 %, the decrease of minimum sea level pressure by 2 %, and the increase of basin-average rainfall by 29.4 % over the Nakdonggang basin in the PGW experiment considering the 2090s SST condition under the SSP2–4.5 scenario in the Typhoon Hinnamnor simulation. Our risk-based approach examining the identified TCs in large ensemble climate dataset found that the maximum sustained wind speed increased by 14 % for Violent Typhoons under +4 K climate, while the minimum sea level pressure decreased by 1 %. Overall, the identified changes in the TC intensity were comparable between the storyline and risk-based approaches, highlighting the robustness of our findings. Furthermore, we analyzed the changes in frequency of TCs affecting South Korea under climate change in the risk-based approach. While we found a decrease (−36 %) in frequency of all category TCs affecting South Korea, the frequency of Violent Typhoons increased (+27 %) under the 4 K warming climate. This study provides useful insights on the TC and its rainfall changes under climate change, which can be incorporated in the regional disaster risk assessment.

北太平洋西部地区经历了热带气旋（tc）造成的破坏，包括台风欣纳诺（2022）在韩国带来的强降雨灾害。这种强台风的强度和频率及其相关降雨的未来变化是全球关注的问题。本研究采用伪全球变暖（PGW）方法，采用故事线方法量化气候变化对台风“欣纳诺”及其相关降雨的影响。此外，我们采用基于风险的方法来检查影响韩国的tc的频率和强度的变化。我们的故事线方法表明，考虑2090年代海温条件，在台风辛纳诺模拟的SSP2-4.5情景下，PGW试验中洛东港盆地最大持续风速增加了15%，最小海平面压力减少了2%，盆地平均降雨量增加了29.4%。我们基于风险的方法分析了大型集合气候数据集中确定的tc，发现在+ 4k气候下，强台风的最大持续风速增加了14%，而最低海平面压力下降了1%。总体而言，在故事情节和基于风险的方法之间，确定的TC强度变化具有可比性，突出了我们研究结果的稳健性。此外，我们用基于风险的方法分析了气候变化下影响韩国的tc频率的变化。虽然我们发现影响韩国的所有类别的台风频率都减少了（- 36%），但在4 K变暖的气候下，强台风的频率增加了（+ 27%）。该研究为气候变化背景下的TC及其降雨变化提供了有益的见解，可用于区域灾害风险评估。

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引用次数: 0

Forecasting convective precipitation over northern Italy: A comparison of lightning and GNSS-ZTD data assimilation 意大利北部对流降水预报：闪电和GNSS-ZTD数据同化的比较

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-08 DOI: 10.1016/j.atmosres.2025.108687

Stefano Federico , Rosa Claudia Torcasio , Claudio Transerici , Eugenio Realini , Xiangyang Song , Giovanna Venuti

Improving the forecast of intense rain events is very important to save lives and properties. In this paper we show the impact of lightning and Global Navigation Satellite System – Zenith Total Delay (GNSS-ZTD) data assimilation on the prediction of intense convective rain events in Northern Italy at the short-range (up to 6 h). A total of 116 cases, from April to September 2019, are considered, based on radar observations over the Lombardy Region. Lightning is assimilated by nudging, while GNSS-ZTD by 3DVar. The Weather and Research Forecast (WRF) model is used for predictions.

Results show that lightning data assimilation and GNSS-ZTD improve the rain forecast. A statistical test shows that the improvement is significant for several thresholds and time ranges. Assimilating both lightning and GNSS-ZTD has a larger positive impact than assimilating one data source alone and, in addition to statistics, few case studies are shown to focus on this point. The forecast performance slightly decreases with time, while the impact of data assimilation decreases faster. Finally, a sensitivity test, aimed at reducing false alarms, shows contradictory results.

改进强降雨天气预报对挽救生命和财产十分重要。在本文中，我们展示了闪电和全球导航卫星系统-天顶总延迟（GNSS-ZTD）数据同化对意大利北部短时（6 h以内）强对流降雨事件预测的影响。根据伦巴第大区的雷达观测，2019年4月至9月共考虑了116起病例。闪电被轻推吸收，而GNSS-ZTD被3DVar吸收。天气和研究预报（WRF）模式用于预测。结果表明，雷电资料同化和GNSS-ZTD技术提高了降雨预报的准确性。统计测试表明，在几个阈值和时间范围内，改进是显著的。吸收闪电和GNSS-ZTD比单独吸收一个数据源具有更大的积极影响，除了统计数据外，很少有案例研究表明关注这一点。随着时间的推移，预报性能略有下降，而数据同化的影响下降较快。最后，一项旨在减少误报的灵敏度测试显示出相互矛盾的结果。

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引用次数: 0

Contributions of Interdecadal Pacific Oscillation, Atlantic Multidecadal Oscillation, and global oceanic warming to the secular change in United States tornado occurrence 年代际太平洋涛动、大西洋多年代际涛动和全球海洋变暖对美国龙卷风发生的长期变化的贡献

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-08 DOI: 10.1016/j.atmosres.2025.108689

Jiuwei Zhao , Luyao Bai , Botao Zhou , Leying Zhang

Tornado has occurred frequently in the United States (US), with its seasonality and interannual variability tremendously discussed in previous studies. However, its long-term variabilities, including the interdecadal/multidecadal variabilities and the linear trend, have less been comprehensively discussed and quantified. In this study, we find that the tornado occurrence in the US shows salient interdecadal/decadal variabilities, in additional to the interannual variability. A modest positive linear trend is also present, qualitatively consistent with the thermodynamic influence of global oceanic warming (GOW) on convective available potential energy and low-level southerly winds. Two internal modes, namely the Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Oscillation (AMO), influence the interdecadal variabilities of tornado occurrence. The IPO stimulates a stationary wave train, propagating from the Pacific to North America, resembles the Pacific-North America pattern yet on the decadal time scale, and affects local circulations and hence tornado occurrence. The AMO induces a local dipole of circulation anomalies, resembling the North Atlantic Oscillation pattern, which triggers a northwest-southeast dipole change of tornado occurrence with the northwest component stronger. Furthermore, we quantitatively estimate the relative importance of IPO, AMO and GOW on the tornado occurrence from 1950 to 2021 based on a multi-regression model. The result shows that the IPO and AMO jointly contribute about 32.6 % (19.9 %) of the decadal (total) variance while the GOW contribution is secondary.

龙卷风在美国频繁发生，以往的研究对其季节性和年际变化进行了大量讨论。然而，其长期变化，包括年代际/多年代际变化和线性趋势，尚未得到全面的讨论和量化。在这项研究中，我们发现美国龙卷风的发生除了年际变化外，还表现出显著的年代际/年代际变化。一个适度的正线性趋势也存在，在质量上与全球海洋变暖（GOW）对对流有效势能和低层南风的热力学影响一致。年代际太平洋涛动（IPO）和大西洋多年代际涛动（AMO）两种内部模态影响龙卷风发生的年代际变化。首次公开募股激发了一个驻波序列，从太平洋传播到北美，类似于太平洋-北美的模式，但在十年时间尺度上，并影响当地环流，从而导致龙卷风的发生。AMO引起局地环流异常偶极子，类似北大西洋涛动型，引起龙卷风发生的西北-东南偶极子变化，西北分量更强。利用多元回归模型定量估计了1950 - 2021年IPO、AMO和GOW对龙卷风发生的相对重要性。结果表明，IPO和AMO共同贡献了约32.6%（19.9%）的年代际（总）方差，而GOW的贡献次之。

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引用次数: 0

Comparative study on microphysical characteristics of two icing and freezing weather events over central China in February 2024 2024年2月中国中部两次结冰冰冻天气微物理特征对比研究

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-08 DOI: 10.1016/j.atmosres.2025.108688

Lingli Zhou , Yue Zhou , Chunsong Lu , Jingjing Lü , Zhikang Fu

To advance our knowledge of formation mechanisms in freezing rain and ice pellets, this study compares microphysical characteristics of two icing and freezing events over central China in February 2024 using co-located PARSIVEL disdrometer and Micro Rain Radar (MRR) at the Xianning national meteorological station. The two events are classified into three categories of rain, freezing rain, and ice pellets. Based on improved multiple bright-band detection method, the MRR can identify the bright band in mid-level warm layer for most samples, with high Probability of Detection (POD) of ∼80 %; whereas the low-level refreezing layer is detected only for ice pellets, with POD of ∼68 %. Rain and freezing rain are featured with a three-phase layer: (1) an ice-phase layer where snow particles transform partially into graupel particles (∼55 %); (2) a melting layer where most particles melt into drizzle/rain particles (∼90 %), with notable bright-band features; (3) a liquid-phase layer where radar reflectivity increase but Doppler velocity decrease, due to collision-coalescence processes. In contrast, ice pellets are characterized by a four-phase layer: (1) an ice-phase layer where most snow particles transform into graupel particles (∼85 %), due to riming processes; (2) a melting layer where graupel particles partially melt into rain/drizzle particles (∼55 %); (3) a multi-phase layer where graupel, mixed, drizzle and rain particles coexist, (4) a refreezing layer with decreased radar reflectivity (∼6 dB) and increased spectral width (∼0.1 m/s). Through an improved understanding of formation and transformation mechanisms of freezing rain and ice pellets, we hope to provide useful information to forecasters for predicting these potentially damaging events.

为了进一步了解冻雨和冰球的形成机制，利用咸宁国家气象站PARSIVEL分差仪和微雨雷达（MRR）对2024年2月中国中部地区两次结冰和冻结事件的微物理特征进行了比较研究。这两个事件被分为三类：雨、冻雨和冰球。基于改进的多亮带检测方法，MRR可以识别大部分样品的中层暖层亮带，检测概率（POD）高达80%；而低水平的再冻结层仅在冰丸中被检测到，POD为68%。雨和冻雨具有三相层的特征：(1)冰相层，其中雪颗粒部分转化为霰颗粒（约55%）；(2)熔化层，其中大多数颗粒融化成毛毛雨/雨颗粒（约90%），具有显著的亮带特征；(3)液相层，由于碰撞-聚结过程，雷达反射率增加，多普勒速度降低。相比之下，冰球的特征是一个四相层：(1)冰相层，其中大多数雪颗粒（约85%）由于边缘过程转变为霰颗粒；(2)霰颗粒部分融化成雨/毛毛雨颗粒的融化层（约55%）；(3)霰、混合、毛毛雨和降雨粒子共存的多相层；(4)雷达反射率降低（~ 6 dB）、光谱宽度增加（~ 0.1 m/s）的再冻结层。通过对冻雨和冰丸形成和转化机制的进一步了解，我们希望为预报员预测这些潜在的破坏性事件提供有用的信息。

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引用次数: 0

Assessing the clear-sky assimilation of FY-3D/HIRAS water vapor data and its impact on Typhoon forecasting FY-3D/HIRAS水汽资料的晴空同化及其对台风预报的影响

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research

Pub Date : 2025-12-07 DOI: 10.1016/j.atmosres.2025.108684

Xiaoying Xu , Zhuoya Ni , Qifeng Lu , Ruixia Liu , Chunqiang Wu , Fu Wang , Xingtao Song

Satellite-borne infrared hyperspectral data offer high-resolution atmospheric vertical information, which is crucial in numerical weather prediction. Assimilating water vapor (WV) data can effectively optimize the humidity fields of models and enhance forecast accuracy. In this study, we employ the four-dimensional variational data assimilation system of the China Meteorological Administration Global Forecasting System (CMA-GFS) to assimilate the data of 20 WV channels selected in the mid-to-upper troposphere from the Fengyun-3D (FY-3D) Hyperspectral Infrared Atmospheric Sounder (HIRAS). Through channel selection, quality control and bias correction, two sets of batch cycling assimilation experiments are conducted to evaluate the impact of data assimilation on analysis fields and forecasting capability of the model. The results indicate that assimilating FY-3D/HIRAS WV data can improve the analysis fields of geopotential height, humidity, temperature and wind, thereby improving the short- to medium-range forecasting skills of the CMA-GFS model. The values of the Equitable Threat Score show that there are improvements in the forecasts of light, moderate and heavy rain categories, indicating that WV data assimilation effectively enhances the accuracy of precipitation forecasts. A case study of Typhoon Gaemi (2024) further illustrates that assimilating WV observations strengthens humidity and vertical motion in the mid-troposphere, thereby improving the accuracy of typhoon track forecasts. Overall, this study validates the application potential of FY-3D/HIRAS WV data and demonstrates the role of the clear-sky assimilation of WV data in numerical weather prediction and typhoon forecasting.

星载红外高光谱数据提供高分辨率的大气垂直信息，这对数值天气预报至关重要。水汽资料的同化可以有效地优化模式的湿度场，提高预报精度。本文利用中国气象局全球预报系统（CMA-GFS）的四维变分同化系统，对风云- 3d （FY-3D）高光谱红外大气探测器（HIRAS）在对流层中高层选取的20个WV通道数据进行同化。通过通道选择、质量控制和偏差校正，进行了两组批量循环同化实验，以评估数据同化对模型分析领域和预测能力的影响。结果表明，同化FY-3D/HIRAS WV数据可以改善位势高度、湿度、温度和风的分析场，从而提高CMA-GFS模式的中短期预报能力。公平威胁评分值显示，小雨、中雨和暴雨预报均有改善，表明WV资料同化有效提高了降水预报的精度。以台风Gaemi（2024）为例进一步说明，同化WV观测增强了对流层中部的湿度和垂直运动，从而提高了台风路径预报的准确性。总体而言，本研究验证了FY-3D/HIRAS WV资料的应用潜力，并论证了晴空同化WV资料在数值天气预报和台风预报中的作用。

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引用次数: 0