Atmospheric Research最新文献_第8页

The characteristics of the atmospheric boundary layer structure over the Cosmonaut Sea and Bellinsgauzen Sea during summer 2021 2021年夏季Cosmonaut海和Bellinsgauzen海大气边界层结构特征

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

Atmospheric Research

Pub Date : 2026-01-16 DOI: 10.1016/j.atmosres.2026.108778

Ting Qiu , Qinghua Yang , Bo Han , Xingya Xi , Zhongya Cai , Shijie Peng , Changwei Liu

Atmospheric boundary layer (ABL) structure over the Southern Ocean not only determines air-sea interactions but also influences local synoptic processes. However, due to the scarcity of observations, it has been rarely investigated. Here, based on the radiosonde observations conducted during the 37th Chinese Antarctic Scientific Expedition, the characteristics of the ABL structure over the Cosmonaut Sea and Bellinsgauzen Sea in the 2021 summer are revealed. The main findings are as follows: (1) The mean ABL height (ABLH) is lower in the ice-covered region than in the open water region, as enhanced radiative cooling and weakened sea-air heat exchange suppress the development of ABL. (2) The Thorpe method can well describe the vertical distribution of turbulent dissipation rate (ε) in ABL, and suggests that there is a noticeable difference in the vertical profile of ε between convective boundary layer and near-neutral boundary layer. (3) A case study of the most intense cyclone in January shows that the mean ABLH is higher during the cyclone period than during non-cyclone periods. Cold advection brought by the cyclone destabilizes stable stratification aloft, promoting the coupling of cloud and ABL. Concurrently, the cyclone-driven strong winds enhance low-level jets, intensify vertical shear, and thereby foster turbulent mixing. Together, these mechanisms strengthen turbulent activity and deepen the ABLH during the cyclone period.

南大洋大气边界层结构不仅决定着海气相互作用，而且影响着局地天气过程。然而，由于观测的缺乏，它很少被研究。利用中国第37次南极科学考察的探空观测资料，揭示了2021年夏季Cosmonaut海和Bellinsgauzen海的ABL结构特征。结果表明：(1)冰覆盖区域的平均海平面高度（ABLH）低于开阔水域，这是由于辐射冷却的增强和海气热交换的减弱抑制了海平面高度的发展。(2) Thorpe方法可以很好地描述ABL湍流耗散率（ε）的垂直分布，表明对流边界层和近中性边界层之间ε的垂直分布有显著差异。(3)以1月最强气旋为例，气旋期平均ABLH高于非气旋期。气旋带来的冷平流破坏了高空稳定的分层，促进了云和ABL的耦合。同时，气旋驱动的强风增强了低空急流，加强了垂直切变，从而促进了湍流混合。这些机制共同加强了气旋期间的湍流活动并加深了ABLH。

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引用次数: 0

Observed aerosol properties and aerosol forecast evaluation in the Arctic region during cold air outbreaks 北极地区在冷空气爆发期间观测到的气溶胶特性和气溶胶预报评价

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

Atmospheric Research

Pub Date : 2026-01-16 DOI: 10.1016/j.atmosres.2026.108781

Lintong Cai , Sunandan Mahant , Emma Weissburg , Anna M. Robertson , Jefferson R. Snider , Markus D. Petters

Arctic aerosols play an important role in modulating high-latitude weather and climate. However, spatiotemporal aerosol distributions in the Arctic remain poorly quantified. Here, we present aerosol physicochemical properties observed during the Cold Air Outbreak Experiment in the Sub-Arctic Region (CAESAR) campaign. The airborne measurements covered a wide vertical range, from the near-surface to the free troposphere, across remote regions between Scandinavia and the coast of Greenland. A merged particle distribution product, spanning from 10 nm to 3 μm in diameter, was developed by combining a suite of five aerosol sensors. Number closure was achieved between the different instruments. Estimated aerosol concentration from the merged size distribution varied between ∼50 and ∼ 700 scm⁻³. Refractory black carbon mass concentrations (70–800 nm) varied between ∼0.9 and ∼ 80.4 ng sm⁻³. Aerosol mass concentration observations were compared to the NASA Goddard Earth Observing System composition forecast (GEOS-CF). The model concentrations correlated with the observations exhibit agreement with the spatial and temporal distribution of localized black carbon aerosol plumes. During Research Flight (RF) 09, the black carbon mass concentration model-vs-observation Pearson correlation coefficient r is 0.84. Observed fine particulate matter (PM_2.5) were significantly larger than the model concentrations within the marine boundary layer (MBL). The high observed PM_2.5 concentrations were due to coarse mode aerosol, suggesting that the model did not accurately capture sea-spray production. Over the study domain, the median normalized mean bias (NMB) was −2454% and the normalized mean root square error (NMRSE) was 35% for PM_2.5; and 1372% (10,619%) and 90% (177%) for refractory black carbon within the marine boundary layer (free troposphere), respectively. The dataset and data/model intercomparison provide new constraints for understanding aerosol properties in the Arctic region.

北极气溶胶在调节高纬度天气和气候方面发挥着重要作用。然而，北极气溶胶时空分布的量化仍然很差。在这里，我们介绍了亚北极地区冷空气爆发实验（CAESAR）运动期间观测到的气溶胶物理化学性质。机载测量覆盖了从近地表到自由对流层的广泛垂直范围，横跨斯堪的纳维亚半岛和格陵兰海岸之间的偏远地区。通过将5个气溶胶传感器组合在一起，开发出了直径从10纳米到3 μm的合并颗粒分布产品。不同仪器之间实现了数字闭合。合并尺寸分布估计的气溶胶浓度在~ 50和~ 700 μ m−3之间变化。难熔黑碳质量浓度（70-800 nm）在~ 0.9 ~ ~ 80.4 ng sm−3之间变化。将气溶胶质量浓度观测结果与NASA戈达德地球观测系统成分预报（GEOS-CF）进行了比较。与观测值相关的模式浓度与局域黑碳气溶胶羽流的时空分布一致。研究飞行（RF） 09期间，黑碳质量浓度模型与观测值的Pearson相关系数r为0.84。观测到的细颗粒物（PM2.5）在海洋边界层（MBL）内显著大于模式浓度。观测到的高PM2.5浓度是由于粗模气溶胶造成的，这表明该模式没有准确地捕捉到海雾的产生。在研究区域内，PM2.5的中位数归一化平均偏差（NMB）为- 2454%，归一化均方根误差（NMRSE）为35%；在海洋边界层（自由对流层）中，难熔黑碳分别占1372%（10,619%）和90%（177%）。数据集和数据/模式的相互比较为了解北极地区气溶胶特性提供了新的约束条件。

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引用次数: 0

Assimilating FY-4B satellite aerosol data to improve PM₂.₅ and surface shortwave radiation prediction 利用FY-4B卫星气溶胶资料改善PM 2。5、表面短波辐射预测

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

Atmospheric Research

Pub Date : 2026-01-14 DOI: 10.1016/j.atmosres.2026.108764

Fangzheng Hu , Feiyue Mao , Yi Zhang , Jia Hong , Lin Zang , Zhaoliang Zeng , Sicong Lin , Wei Gong , Daniel Rosenfeld

Aerosols significantly impact solar radiation forecasts, but substantial uncertainties persist in numerical models due to inadequate aerosol representation. This study develops a data assimilation framework integrating hourly surface-level particulate matter (PM₂.₅) retrievals from the FY-4B geostationary satellite into the WRF-Chem model with solar radiation diagnostics via the Gridpoint Statistical Interpolation (GSI) three-dimensional variational (3DVAR) system. Assimilation experiments conducted over central and eastern China in November 2022 demonstrate marked improvements in PM₂.₅ forecasts, with correlation coefficients increasing from 0.39 to 0.82, and root mean square error (RMSE) decreasing by approximately 45%. Improved aerosol initial conditions significantly reduce uncertainties in surface downward shortwave radiation (SWDOWN) predictions, lowering midday bias by over 50% and RMSE by roughly 40% across the domain. Consistent forecast enhancements were verified through spatiotemporal analyses across various pollution levels. These results highlight the practical value of assimilating hourly FY-4B PM₂.₅ retrievals for simultaneously improving air quality and solar radiation forecasts. The proposed assimilation approach offers a robust, replicable solution for near-real-time operational forecasting, thereby supporting photovoltaic energy planning and effective air quality management.

气溶胶显著影响太阳辐射预报，但由于气溶胶表征不足，数值模式存在很大的不确定性。本研究开发了一个数据同化框架，通过网格点统计插值（GSI）三维变分（3DVAR）系统，将每小时从FY-4B地球静止卫星获取的地表颗粒物质（PM₂.₅）整合到WRF-Chem模型中，并进行太阳辐射诊断。2022年11月在中国中东部地区进行的同化试验表明，PM 2有明显改善。₅预测，相关系数从0.39增加到0.82，均方根误差（RMSE）减少约45%。改善的气溶胶初始条件显著降低了地表向下短波辐射（SWDOWN）预测的不确定性，将整个区域的正午偏差降低了50%以上，RMSE降低了大约40%。通过对不同污染水平的时空分析，验证了预测的一致性增强。这些结果突出了每小时同化FY-4B PM 2的实用价值。5回收，同时改善空气质量和太阳辐射预报。所提出的同化方法为近实时运行预测提供了一个强大的、可复制的解决方案，从而支持光伏能源规划和有效的空气质量管理。

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引用次数: 0

Synergy between land-sea breeze dynamics and photochemistry governs the diurnal variability of primary and secondary organic aerosols in a tropical coastal atmosphere 陆海风动力学和光化学的协同作用支配着热带沿海大气中初级和次级有机气溶胶的日变化

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

Atmospheric Research

Pub Date : 2026-01-14 DOI: 10.1016/j.atmosres.2026.108777

Suresh K.R. Boreddy, Vijayakumar S. Nair, Prashant Hegde, S. Suresh Babu

Coastal tropical regions are ideal for studying sources and processes of organic aerosols (OA) due to their high humidity and solar radiation, with land- and sea-breeze circulations influencing OA transport. However, their molecular characteristics in these areas are not well understood. This study analysed PM₁₀ samples from Thumba (8.5°N, 76.9°E, approximately 3 m above sea level, a coastal location in tropical India), collected on day and night basis during the pre-monsoon period, detecting various classes of organic molecular markers including biomass-burning, biological, aromatic compounds, phthalates, and biogenic secondary organic compounds using gas chromatography/mass spectrometry (GC/MS). Results showed that total quantified organic compounds were twice as abundant during the daytime, indicating that photochemical processes are the primary sources. Phthalates and aromatics were the dominant compounds throughout the sampling period. This suggests that OA production primarily results from plastic evaporation during the day, while municipal solid waste burning occurs mostly at night, as confirmed by higher daytime phthalate emissions and nighttime terephthalic acid emissions (a tracer of plastic combustion). The presence of primary sugars and sugar alcohols during the day implies that plant emissions (pollen, spores) are significant sources of primary OA. In contrast, nighttime hydroxy and polyacids indicate secondary OA formation associated with anthropogenic emissions. Furthermore, monoterpene-derived secondary organic products were more prevalent than those from isoprene, especially during daylight hours. OA particles from biomass burning were minimal, as evidenced by lower levels of anhydrosugars and lignin/resin products. Overall, the present study highlights that the photochemical degradation of phthalates and the burning of municipal solid waste containing plastics are significant sources of OA at Thumba during the pre-monsoon, with land-sea breeze transport and photodegradation/evaporation influencing their diurnal variation. The prominence of phthalates and aromatics highlight the importance of understanding airborne nanoplastics and their climate effects in tropical coastal atmospheres.

热带沿海地区具有较高的湿度和太阳辐射，是研究有机气溶胶（OA）来源和过程的理想场所，而陆地和海风环流会影响OA的输送。然而，它们在这些区域的分子特征尚不清楚。本研究分析了在季风前昼夜收集的来自Thumba（北纬8.5°，东经76.9°，海拔约3米，位于印度热带沿海地区）的PM10样本，利用气相色谱/质谱（GC/MS）检测了各种类型的有机分子标记，包括生物质燃烧、生物、芳香族化合物、邻苯二甲酸盐和生物源二级有机化合物。结果表明，总定量有机化合物的丰度是白天的两倍，表明光化学过程是主要来源。邻苯二甲酸酯和芳烃是整个采样期间的主要化合物。这表明OA的产生主要是由于白天的塑料蒸发，而城市固体废物的燃烧主要发生在夜间，这一点得到了日间邻苯二甲酸盐排放量和夜间对苯二甲酸（塑料燃烧的一种示踪剂）排放量较高的证实。白天原始糖和糖醇的存在意味着植物排放物（花粉、孢子）是原始OA的重要来源。相反，夜间羟基和多酸表明次生OA的形成与人为排放有关。此外，单萜烯衍生的二次有机产物比异戊二烯衍生的二次有机产物更普遍，特别是在白天。生物质燃烧产生的OA颗粒很少，无水糖和木质素/树脂产物的含量较低。总的来说，本研究强调，在季风前，邻苯二甲酸盐的光化学降解和含塑料的城市固体废物的燃烧是Thumba OA的重要来源，陆海风运输和光降解/蒸发影响它们的日变化。邻苯二甲酸酯和芳烃的突出突出了了解空气中纳米塑料及其在热带沿海大气中的气候影响的重要性。

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引用次数: 0

Atmospheric aerosol light scattering and absorption properties in the urban area of Milan (Italy): A focus on aerosol typing 意大利米兰市区大气气溶胶光散射和吸收特性：气溶胶类型的重点

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

Atmospheric Research

Pub Date : 2026-01-14 DOI: 10.1016/j.atmosres.2026.108776

Stefano Rimoldi , Marcus Acton-Bond , Vera Bernardoni , Laura Cadeo , Gianluigi Valli , Cristina Colombi , Rosario Cosenza , Manousos-Ioannis Manousakas , Benjamin Chazeau , Roberta Vecchi

In this work, aerosol absorption and scattering properties were investigated to gather additional information on aerosol types and sources. During a one-year campaign in Milan (Italy), a multi-wavelength aethalometer and a nephelometer were operated in parallel. Scattering coefficients are in general scarcely available at urban sites and this was the very first dataset for Milan and, more generally, for an urban site in the Po valley which is a well-known pollution hot-spot in Europe.

Time patterns of the absorption and scattering coefficients throughout the year were investigated and Absorption/Scattering Ångström Exponents (AAE and SAE, respectively) were also computed to relate the optical properties to fossil vs. wood fuel combustion emission sources and to small vs. large particle size. The average daily trends for the absorption coefficients reflected the behaviour of the sources, with peaks in the morning due to traffic emissions observed in all seasons, and high values during the night as a consequence of lower mixing heights and, in winter, of domestic heating emissions, too.

To gain knowledge about aerosol types and origin an innovative cluster analysis approach using AAE and SAE led to the identification of different aerosol types; this is an easy-to-implement approach which could be applied in monitoring networks for near-real time aerosol types identification. Moreover, episodes affected by specific aerosol types (i.e., fire event, desert dust air mass transport…) were singled out applying a more refined approach combining five intensive optical parameters.

在这项工作中，研究了气溶胶的吸收和散射特性，以收集有关气溶胶类型和来源的额外信息。在米兰（意大利）进行的为期一年的活动中，一个多波长酒精计和一个浊度计并行工作。散射系数一般很难在城市站点获得，这是米兰的第一个数据集，更一般地说，是波河流域的一个城市站点的数据集，波河流域是欧洲众所周知的污染热点。研究了全年吸收和散射系数的时间模式，并计算了吸收/散射Ångström指数（分别为AAE和SAE），以将光学特性与化石燃料与木材燃料燃烧排放源以及小颗粒与大颗粒尺寸联系起来。吸收系数的平均日趋势反映了源的行为，由于在所有季节观测到的交通排放，在早晨达到峰值，由于混合高度较低，在夜间也有高值，在冬季，家庭供暖排放也有高值。为了获得气溶胶类型和来源的知识，采用创新的聚类分析方法，使用AAE和SAE来识别不同的气溶胶类型；这是一种易于实现的方法，可以应用于监测网络中进行近实时的气溶胶类型识别。此外，受特定气溶胶类型影响的事件（例如，火灾事件、沙漠沙尘气团运输……）通过结合五个密集光学参数的更精细的方法被挑选出来。

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引用次数: 0

Cost-benefit analysis of the nesting approach in HARMONIE-AROME for a supercell outbreak case study 一个超级单体暴发案例研究中HARMONIE-AROME筑巢方法的成本效益分析

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

Atmospheric Research

Pub Date : 2026-01-13 DOI: 10.1016/j.atmosres.2026.108774

J. Díaz-Fernández , C. Calvo-Sancho , M. López-Reyes , P. Bolgiani , J.J. González-Alemán , A. Morata , D. Santos-Muñoz , M.L. Martín

Supercells are among the most hazardous convective systems, frequently producing large hail, destructive winds, and severe socio-economic impacts. The enhancement of weather simulations is identified as a primary strategy to optimise short-term forecasting. The present study investigates the performance of two high-resolution configurations of the HARMONIE-AROME model during a severe supercell outbreak over eastern Iberia on 31st July 2015, when six confirmed supercells caused significant damage. The setups tested include a two-step one-way nested approach (2.5 km outer domain and 500 m inner domain), and a single-domain configuration at 500 m resolution. The model outputs, which include reflectivity, precipitation and temperature, are validated against OPERA radar composites and surface observations. At the same time, key convective parameters, derived from the Murcia sounding, are analyzed to assess the pre-convective environment. Although the simulations demonstrate a similar structure to the observed event, the two-domain nested simulation offers a slightly superior depiction of reflectivity and thermodynamic profiles. Nevertheless, precipitation analysis reveals that while nesting improves moderate rainfall representation, it introduces larger errors for the most extreme amounts, limiting its overall benefit. The obtained gain is not sufficient to offset the 30% higher computational cost when the two-domain nested approach is used. The single-domain non-nested configuration demonstrates a superior level of efficiency, exhibiting equivalent accuracy while exhibiting a diminished resource requirement.

超级单体是最危险的对流系统之一，经常产生大冰雹、破坏性风和严重的社会经济影响。加强天气模拟被认为是优化短期预报的主要策略。本研究调查了2015年7月31日伊比利亚东部严重超级单体爆发期间HARMONIE-AROME模型的两种高分辨率配置的性能，当时有6个确认的超级单体造成了重大损害。测试的设置包括两步单向嵌套方法（2.5公里外域和500米内域），以及500米分辨率的单域配置。模型输出包括反射率、降水和温度，并与OPERA雷达复合材料和地面观测数据进行了验证。同时，对穆尔西亚探测得到的关键对流参数进行了分析，评价了对流前环境。虽然模拟显示了与观测事件相似的结构，但双域嵌套模拟提供了对反射率和热力学剖面的稍微优越的描述。然而，降水分析表明，虽然嵌套改善了中等降雨量的表现，但它在最极端的降雨量中引入了更大的误差，限制了它的总体效益。当使用双域嵌套方法时，所获得的增益不足以抵消30%的高计算成本。单域非嵌套配置显示了更高的效率水平，显示出同等的准确性，同时显示出减少的资源需求。

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引用次数: 0

AdaBoost-based satellite detection of summer daytime sea fog and low clouds in ice floe fields of the Arctic 基于adaboost的北极浮冰区夏季日间海雾和低云的卫星探测

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

Atmospheric Research

Pub Date : 2026-01-13 DOI: 10.1016/j.atmosres.2026.108775

Huiyun Ma , Jiedong Liu , Zengwei Liu , Huihui Feng , Guannan Li , Runxi Gu

Under the trend of global warming, the Arctic region has experienced increasing warming and accelerating melting of sea ice, resulting in the opening of Arctic shipping routes with significant navigational potential. However, intense water vapor releases and a cold underlying surface can lead to frequent occurrences of sea fog and low clouds over the Arctic ice surfaces. Conducting detection of sea fog and low clouds is therefore highly important for ensuring the safety of Arctic shipping routes. In this study, a satellite detection algorithm for summer daytime sea fog and low clouds in ice floe fields of the Arctic has been proposed using the time series remote sensing data from the Moderate-Resolution Imaging Spectroradiometer (MODIS) and the AdaBoost method. Methodologically, three spectral indices, the normalized difference sea-water index (NDSWI), the sea-ice recognition index (SIRI), and the mid-high-cloud recognition index (MHCRI), are first constructed by analyzing the variations in reflection spectra for sea fog and low clouds, sea ice, sea water, and mid-high clouds. Additionally, three texture features, namely, the homogeneity, contrast, and entropy, of the brightness temperature at 11.030 μm (BT_{11.030 μm}) are calculated using the gray-level co-occurrence matrix (GLCM). Subsequently, a strong learner classification model of the AdaBoost ensemble learning algorithm was built by adopting the samples of the spectral indices and texture features above and the weak learner of the decision. Finally, the residual mid-high clouds are removed through the threshold at BT_{11.030 μm}. Verification indicated that the probability of detection (POD), false alarm rate (FAR), and critical success index (CSI) values were 84.44%, 9.45%, and 77.52%, respectively. This research supports the accurate detection of sea fog and low clouds in the Arctic, thereby ensuring safe navigation of Arctic shipping routes.

在全球变暖趋势下，北极地区气候变暖加剧，海冰加速融化，开辟了具有巨大航行潜力的北极航线。然而，强烈的水蒸气释放和寒冷的下层表面会导致北极冰表面频繁出现海雾和低云。因此，监测海雾和低云对保障北极航道安全具有重要意义。本文利用中分辨率成像光谱仪（MODIS）的时间序列遥感数据和AdaBoost方法，提出了一种北极浮冰区夏季日间海雾和低云的卫星探测算法。在方法上，通过分析海雾和低云、海冰、海水和中高云的反射光谱变化，首先构建归一化差分海水指数（NDSWI）、海冰识别指数（SIRI）和中高云识别指数（MHCRI）三个光谱指数。利用灰度共生矩阵（GLCM）计算了11.030 μm （BT11.030 μm）亮度温度的均匀性、对比度和熵三个纹理特征。随后，采用上述光谱指标和纹理特征的样本和决策的弱学习者，构建AdaBoost集成学习算法的强学习者分类模型。最后，通过阈值BT11.030 μm去除残余中高云。验证表明，检测概率（POD）、虚警率（FAR）和临界成功指数（CSI）值分别为84.44%、9.45%和77.52%。本研究支持对北极海域雾和低云的准确探测，从而保障北极航道的安全航行。

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引用次数: 0

Unravelling the drivers of the April–May 2024 extreme precipitation event in Rio Grande do Sul 揭开2024年4 - 5月巴西南格兰德州极端降水事件的驱动因素

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

Atmospheric Research

Pub Date : 2026-01-12 DOI: 10.1016/j.atmosres.2026.108773

Albenis Pérez-Alarcón , Rogert Sorí , Milica Stojanovic , Renata Libonati , Ricardo M. Trigo , Raquel Nieto , Luis Gimeno

This study examines the extreme precipitation event that caused unprecedented flooding in Rio Grande do Sul (RS), Brazil, during April–May 2024, leading to record-breaking floods in Porto Alegre. Using data from the European Centre for Medium-Range Weather Forecasts ERA5, the high-resolution Multi-Source Weighted-Ensemble Precipitation dataset, a Lagrangian moisture tracking approach, and an analogue-based analysis, we identified the atmospheric drivers and moisture sources fueling this event. Results show that a persistent, quasi-stationary dipole configuration, consisting of a high over the South Atlantic and a deep low over southern South America, drove this extreme event. This configuration, reinforced by heat wave conditions over central and southeastern Brazil, favoured a sustained, atmospheric river-like moisture transport from the Amazon region, channelled by a strengthened South American Low-Level Jet east of the Andes, configuring a compound event. We also found that the highest moisture contribution occurred predominantly 1–3 days before the precipitation over RS. The analogue-based analysis revealed that while the mean sea level pressure (MSLP) pattern was uncommon but not unique within the 1991–2020 reference period, the RS extreme event exhibited significantly enhanced moisture transport and uptake from the Amazon region compared to similar past occurrences. Additionally, we found lower predictability and persistence of the MSLP pattern during this event than that of its analogues. Overall, this research underscores the critical role of specific large-scale atmospheric patterns and sustained anomalous moisture supply in driving extreme precipitation, reinforcing the need for an improved understanding of climate-weather interactions and the development of mitigation strategies to address intensifying extreme precipitation events in a changing climate.

本研究考察了2024年4月至5月在巴西南里约热内卢Grande do （RS）造成前所未有洪水的极端降水事件，该事件导致阿雷格里港（Porto Alegre）发生破纪录的洪水。利用来自欧洲中期天气预报中心ERA5的数据、高分辨率多源加权集合降水数据集、拉格朗日水分跟踪方法和基于模拟的分析，我们确定了这一事件的大气驱动因素和水分来源。结果表明，由南大西洋上空的高压和南美洲南部上空的深低压组成的持续的准平稳偶极子结构驱动了这次极端事件。巴西中部和东南部的热浪条件加强了这种结构，有利于亚马孙地区持续的、大气中河流般的水汽输送，由安第斯山脉以东加强的南美低空急流引导，形成一个复合事件。基于模拟的分析表明，虽然1991-2020年的平均海平面压力（MSLP）模式不常见，但并非唯一，但与过去类似事件相比，RS极端事件显著增强了亚马逊地区的水分输送和吸收。此外，我们发现MSLP模式在这次事件中的可预测性和持久性较低。总的来说，这项研究强调了特定的大尺度大气模式和持续的异常湿度供应在驱动极端降水中的关键作用，加强了对气候-天气相互作用的理解和制定缓解战略的必要性，以应对气候变化中日益加剧的极端降水事件。

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引用次数: 0

A novel approach for assimilating GNSS tropospheric gradient information to improve numerical weather prediction 同化GNSS对流层梯度信息以改进数值天气预报的新方法

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

Atmospheric Research

Pub Date : 2026-01-12 DOI: 10.1016/j.atmosres.2026.108769

Yuxin Zheng , Cuixian Lu , Jiafeng Li , Jan Dousa , Xiaohong Zhang

Global Navigation Satellite System (GNSS) has emerged as a well-established atmospheric observing system, with Zenith Total Delay (ZTD) and integrated water vapor routinely assimilated by several global and regional Numerical Weather Prediction (NWP) centers. While co-derived tropospheric gradients effectively capture water vapor horizontal anisotropy, their assimilation has yet to be widely adopted. Here, we introduce a novel approach for assimilating GNSS tropospheric gradients into the Weather Research and Forecasting (WRF) model by constructing pseudo-ZTD observations from GNSS-derived ZTD and gradient data. Through two comparative experiments, we evaluate the potential influence of GNSS tropospheric gradients on WRF forecasts. The results indicate that assimilating these gradients improves humidity and wind field predictions in the lower-to-middle troposphere (850–500 hPa), with a neutral impact on surface fields. Verification against radar estimates further demonstrates enhanced precipitation forecast skills, particularly for heavy precipitation events, by better resolving the spatial distribution and intensity of precipitation systems. A diagnosis of a precipitation event suggests that the assimilation of GNSS tropospheric gradients is able to adjust the forecast mid-level moisture distribution and modulate the forecast upward motion, thereby influencing the formation of spurious precipitation.

全球导航卫星系统（GNSS）是一种成熟的大气观测系统，其天顶总延迟（ZTD）和综合水汽通常被几个全球和区域数值天气预报（NWP）中心吸收。虽然共同导出的对流层梯度有效地捕获了水汽的水平各向异性，但它们的同化尚未被广泛采用。本文提出了一种新的方法，利用GNSS导出的ZTD和梯度数据构建伪ZTD观测值，将GNSS对流层梯度同化到天气研究与预报（WRF）模型中。通过两个对比实验，我们评估了GNSS对流层梯度对WRF预报的潜在影响。结果表明，同化这些梯度可以改善对流层中下层（850 ~ 500 hPa）的湿度和风场预测，对地面场的影响为中性。通过更好地解析降水系统的空间分布和强度，对雷达估计的验证进一步证明了降水预报技能的提高，特别是对于强降水事件。对一次降水事件的诊断表明，GNSS对流层梯度的同化能够调整预报的中层水汽分布并调节预报的上升运动，从而影响假降水的形成。

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引用次数: 0

Spatiotemporal Variability of China's 800 mm Precipitation Isohyet (1961–2022): Multi-scale Analysis of its Migration and Impact on Hydroclimatic Extremes 第1节中国800mm降水等雨量（1961-2022）的时空变异：多尺度迁移及其对水文气候极端事件的影响

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

Atmospheric Research

Pub Date : 2026-01-12 DOI: 10.1016/j.atmosres.2026.108770

Shaowei Ning , Le Chen , Rujian Long , Yuliang Zhou , Yi Cui , Min Zhang , Lichang Xu , Juliang Jin , Thapa bthapa

Under global climate change, precipitation variability and extreme events pose significant challenges to regional ecological security and water resource management. This study proposes the Dynamic Line Scanning Method (DLSM) to quantitatively assess the migration of China's 800 mm precipitation isohyet during 1961–2022. Using long-term precipitation data, we systematically examined its spatial and temporal variation, explored links with drought–flood regimes and extreme precipitation, and identified the main drivers. Results indicate that the isohyet experienced a two-phase shift: an initial southward retreat followed by accelerated northward movement after 2001, with the latter trend markedly intensifying. These shifts have directly influenced regional drought–flood patterns and altered the frequency and intensity of extreme precipitation events. Analysis further reveals that the East Asian Summer Monsoon Index (EASMI) is the dominant factor driving the isohyet's movement. Overall, this study provides novel methodological insights and robust empirical evidence regarding the dynamics of precipitation isohyets in China in the context of climate change. The findings enhance understanding of hydroclimatic variability and offer a scientific foundation for developing region-specific adaptation and water management strategies.

在全球气候变化背景下，降水变率和极端事件对区域生态安全和水资源管理提出了重大挑战。本文提出了动态线扫描法（DLSM）定量评价1961-2022年中国800mm降水等雨量线的迁移。利用长期降水数据，系统分析了其时空变化，探讨了其与旱涝和极端降水的联系，并确定了主要驱动因素。结果表明，该等雨量线经历了两个阶段的变化，即2001年以后先向南撤退，然后加速向北移动，后一阶段的趋势明显加剧。这些变化直接影响了区域旱涝格局，并改变了极端降水事件的频率和强度。进一步分析表明，东亚夏季风指数（EASMI）是驱动等雨量线运动的主导因素。总体而言，本研究为气候变化背景下中国降水等线的动态提供了新的方法见解和有力的经验证据。这些发现增强了对水文气候变率的认识，并为制定区域适应和水管理战略提供了科学基础。

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引用次数: 0