Meteorologische Zeitschrift最新文献

{"title":"High-resolution ensemble LES energy balance closure study of the LITFASS-2003 campaign","authors":"Sadiq Huq, Frederik De Roo, Matthias Sühring, Luise Wanner, Matthias Mauder","doi":"10.1127/metz/2024/1213","DOIUrl":"https://doi.org/10.1127/metz/2024/1213","url":null,"abstract":"The imbalance between the measured available energy and the sum of the turbulent fluxes lead to the energy balance closure problem. In spite of several experimental and modelling studies, the reasons for the lack of closure are not fully understood, particularly, in a heterogeneous terrain. The LITFASS-2003 campaign in Northeastern Germany was designed to develop and to assess different area-averaging strategies of the surface fluxes over a heterogeneous land surface. The micrometeorological measurements of the campaign were targeted at local fluxes over different types of land surface that are essential to study the energy balance closure problem for a complex land surface where the secondary circulations induced by surface heterogeneity are suspected to influence the surface energy budget imbalance. To assess the influence of the secondary circulations we perform large-eddy simulations of a 5.4 × 5.4 km2 sub-region of the LITFASS area with a flat topography and composed mainly of agricultural land. The boundary conditions for the simulation domain is derived from the experimental data collected on 30 May 2003. To capture the spatial variation of the fluxes, the surface fluxes of latent and sensible heat flux in the simulated domain are prescribed by composite fluxes derived from multiple surface flux stations operated during the experiment. A grid resolution of 1 m in the vertical and 2 m in the horizontal directions up to 72 m from the ground is achieved by employing a nested large-eddy simulation model. A total of five realizations of the domain is performed to calculate ensemble averages to separate the heterogeneity effect from the turbulence fluctuations and the 30-minute time-averaging ensures more representative statistics. We find the underestimation to be systematic and to increase with height. At a typical eddy covariance tower height of 10 m, we find the dispersive flux represents up to 5% of the prescribed surface fluxes, which partially explains the imbalance in the field measurements.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of volcanic sulfur dioxide on solar UV irradiance during the 2023 Fagradalsfjall eruption in Reykjavík, Iceland","authors":"Klára Čížková, Kamil Láska, David Tichopád, Ladislav Metelka, Martin Staněk, Árni Sigurðsson","doi":"10.1127/metz/2024/1224","DOIUrl":"https://doi.org/10.1127/metz/2024/1224","url":null,"abstract":"Sulfur dioxide is an important atmospheric gas that can attenuate solar ultraviolet radiation. It can be found in greater quantities in highly polluted areas and especially in volcanic plumes. During the eruption of the Icelandic volcanic system Fagradalsfjall, which lasted between 10 July and 5 August 2023, the sulfur dioxide plume reached the capital city Reykjavík on 24 July 2023, resulting in almost 50 DU column of this gas, as measured by a B199 MkIII Brewer spectrophotometer. The increased sulfur dioxide concentration resulted in ~25 % reduction in UV Index, compared to only 1 % decrease on 23 July 2023, when up to 3.6 DU sulfur dioxide were recorded. In the UV spectrum, sulfur dioxide affected mostly short wavelengths up to approximately 325 nm, above which the effects were negligible. On 24 July 2023, a 50 DU sulfur dioxide column lead to more than 79 % reduction of UV irradiance at 296 nm. Model simulations showed that a 100 DU column sulfur dioxide would attenuate 96 % of UV irradiance at this wavelength. The effects of sulfur dioxide on vitamin D weighted solar UV irradiance were even greater than on UV Index, as a 50 DU sulfur dioxide column caused a 37 % decline in vitamin D weighted solar UV irradiance, and a potential 100 DU column of this gas would lead to a 58 % reduction of vitamin D production.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the ability of regional extrapolation for precipitation nowcasting with deep learning","authors":"Tarek Beutler, Annette Rudolph, Daniel Goehring, Nikki Vercauteren","doi":"10.1127/metz/2024/1189","DOIUrl":"https://doi.org/10.1127/metz/2024/1189","url":null,"abstract":"Precipitation nowcasting refers to the prediction of precipitation intensity in a local region and in a short timeframe up to 6 hours. The evaluation of spatial and temporal information still challenges state-of-the-art numerical weather prediction models. The increasing possibilities to store and evaluate data combined with the advancements in the developments of artificial intelligence algorithms make it natural to use these methods to improve precipitation nowcasting. In this work, a Trajectory Gated Recurrent Unit (TrajGRU) is applied to radar data of the German Weather Service. The impact of finetuning a network pretrained at a different location and for several precipitation intensity thresholds with respect to the training time is evaluated. In cases with little availability of training data at the target location, for example when heavy rainfall is rare, the finetuned model can benefit from the original model performance at the pretraining location. Furthermore, the skill scores for the different thresholds are shown for a prediction time up to 100 minutes. The results highlight promising regional extrapolation capabilities for such neural networks for precipitation nowcasting.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of rain cells over the northwest Pacific warm pool","authors":"Ping Ye, Aoqi Zhang","doi":"10.1127/metz/2024/1212","DOIUrl":"https://doi.org/10.1127/metz/2024/1212","url":null,"abstract":"The importance of precipitation morphology has been emphasized by recent studies. However, the specific morphological characteristics of rain cells (RCs) and their impact on rainfall intensity over the oceans remain unclear. In this study, using 15-year observations from Tropical Rainfall Measurement Mission (TRMM) Precipitation Radar (PR), more than 600 thousand RCs in the northwest Pacific warm pool were identified and approximated by rectangle. The results showed that the horizontal scale of RCs was negatively correlated with their occurrence frequency, while there was a logarithmic correlation between the length and width of the approximated rectangle. The morphology of RCs presented huge zonal differences but small meridional differences over the study region. RCs had larger scale, narrower 2-D shape, and slender 3-D shape in the southern region compared with ones in the northern region. Precipitation intensity generally increased with the enlargement of the horizontal scale. The relationships between precipitation intensity and shape of RCs were very complex. Moderate shape of RCs had the weakest precipitation, whereas 2-D narrower or 3-D slender RCs had the strongest precipitation. The results would be helpful for monitoring and predicting precipitating clouds over the oceans.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observations and forecasting of a low visibility event in Hong Kong on New Year’s Eve","authors":"Jielan Xie, Pak-Wai Chan, Wai-yin Ng, Hiu-fai Tam","doi":"10.1127/metz/2024/1220","DOIUrl":"https://doi.org/10.1127/metz/2024/1220","url":null,"abstract":"This paper investigates a unique low visibility event induced by haze in Hong Kong on New Year’s Eve 2023, characterized by significant spatial differences in visibility across Victoria Harbour. The study discusses the meteorological conditions, including weak northeast monsoon and localized wind variations, leading to the rapid fluctuation in visibility. Ground observations, remote-sensing data, and Aerosol Optical Depth (AOD) from satellites were utilized to analyze the phenomenon. The research highlights the impact of surface winds, boundary layer stability, and aerosol dispersion in understanding the visibility variation. Additionally, the study assesses the effectiveness of the current forecasting techniques, especially the high-resolution numerical weather prediction model utilized by Hong Kong’s Environmental Protection Department. The paper serves as a valuable resource for weather forecasters in the region and suggests further studies using high-resolution models to better understand localized visibility deterioration events.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142220178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lagrangian transport based on the winds of the icosahedral nonhydrostatic model (ICON)","authors":"Jonas Sonnabend, Jens-Uwe Grooß, Felix Ploeger, Lars Hoffmann, Patrick Jöckel, Bastian Kern, Rolf Müller","doi":"10.1127/metz/2024/1207","DOIUrl":"https://doi.org/10.1127/metz/2024/1207","url":null,"abstract":"Representing atmospheric transport of constituents accurately in a chemistry climate model is a challenge. This is true in particular for a realistic representation of atmospheric transport barriers, e.g. at the edge of the polar vortices or at the tropopause. When transport is represented employing Lagrangian methods, numerical problems representing transport barriers may be obviated. Here, we present a first implementation of a Lagrangian transport model (the Chemical Lagrangian Model of the Stratosphere, CLaMS) driven by horizontal winds and vertical velocities of the icosahedral nonhydrostatic model (ICON) using the Modular Earth Submodel System (MESSy). The diabatic heating rates deduced from the temperature tendencies in the (free-running) ICON model allow vertical velocities to be determined and transport calculations in isentropic (diabatic) coordinates. The deduced diabatic heating rates agree qualitatively well with ERA5 reanalysis values in the zonal annual mean, but some discrepancies remain. Further, there is an overall agreement between the simulation and N2O observations by the Microwave Limb Sounder (MLS) satellite instrument; in particular regarding N2O gradients at the edge of the polar vortex. Overall, the Antarctic vortex and the associated transport barrier at its edge are well represented in the simulation, although the simulated polar vortex is larger than observed. Some differences between the observations and the Lagrangian simulation may be caused by the underlying ICON winds. The coupled ICON/MESSy-CLaMS transport scheme allows realistic simulations of tracer distributions in the free troposphere and in the stratosphere, including the representation of tracer gradients across transport barriers, a feature generally more difficult to obtain by classical Eulerian schemes.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Survey On Output Data From Obstacle Resolving Atmospheric Models","authors":"Vivien Voss, K. Heinke Schlünzen, David Grawe","doi":"10.1127/metz/2024/1217","DOIUrl":"https://doi.org/10.1127/metz/2024/1217","url":null,"abstract":"Obstacle resolving micro-scale atmospheric models (ORMs) are important to assess atmospheric processes within urban areas. However, the data generated from such models are not standardised yet and existing data standards do not fit properly to those data. Standardised model data can help to prepare FAIR data publications, which foster the process of data reuse, sharing, comparison and distribution. Therefore, an online survey was distributed among ORM users and developers in the urban meteorology and urban climate community. The survey should help to assess, which models are currently in use and to collect suggestions and requirements from the participants on how a data standard should look like. The aim of the survey was not to test the knowledge of the participants about the model they use but rather to get an overview of how they understand, use and work with ORMs. Based on 14 finished survey entries, it shows that ORMs provide and handle their data differently. The participants are aware of the need for standardisation, preferring netCDF as data format and suggesting extending existing standards to the needs of ORM data.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The TEAMx‑PC22 Alpine field campaign – Objectives, instrumentation, and observed phenomena","authors":"Lena Pfister, Alexander Gohm, Meinolf Kossmann, Andreas Wieser, Nevio Babić, Jan Handwerker, Norman Wildmann, Hannes Vogelmann, Kathrin Baumann-Stanzer, Almut Alexa, Karl Lapo, Ivan Paunović, Ronny Leinweber, Katrin Sedlmeier, Manuela Lehner, Alexander Hieden, Johannes Speidel, Maria Federer, Mathias W. Rotach","doi":"10.1127/metz/2024/1214","DOIUrl":"https://doi.org/10.1127/metz/2024/1214","url":null,"abstract":"The multi‑scale transport and exchange processes in the atmosphere over mountains—programme and experiment (TEAMx) wants to advance the understanding of transport and exchange processes over mountainous terrain as well as to collect unique multi‑scale datasets that can be used, e.g., for process studies, model development and model evaluation. The TEAMx Observational Campaign (TOC) is planned to take place between 2024 and 2025. In summer 2022 a TEAMx pre‑campaign (TEAMx‑PC22) was conducted in the Inn Valley and one of its tributaries, the Weer Valley, to test the suitability and required logistics of measurement sites, to evaluate their value for the main campaign, and to test new observation techniques in complex terrain. Scientifically, this campaign focused on resolving the mountain boundary layer and valley wind systems on multiple scales. Through the combined effort of six institutions the pre‑campaign can be deemed successful. A detailed description of the setup at each sub‑target area is given. Due to the spatial distribution of instruments and their spatio-temporal resolution, atmospheric processes and phenomena like valley winds have been investigated at different locations and on different scales. Furthermore, scale interactions were detected and are discussed in detail in example cases. Additionally, observational gaps were determined which should be closed for the TOC. Data of the pre‑campaign are publicly available online and can be used for process studies, demonstrating the utility of new observation methods, model verification, and for data assimilation.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term variations of global radiation in Central Europe 1950–2020 and their impact on terrestrial surface air warming","authors":"Jürg Thudium, Carine Chélala","doi":"10.1127/metz/2024/1201","DOIUrl":"https://doi.org/10.1127/metz/2024/1201","url":null,"abstract":"The variation of global radiation from 1950–2020 and its impact on the terrestrial surface air warming was investigated based on measurements of sunshine duration, global radiation and temperature from six measuring stations from the national weather services in Austria, Switzerland and Germany. A quantitative estimation of that impact was conducted with the help of a multiple linear regression model based on monthly values from the period 1950–2020. The applicability of this approach was ensured by a set of five statistical standard tests. The overall temperature increase from 1950–2020 (about +2.1 °C in the annual and summer semi-annual average at the six measuring stations) is dominated by the temporally continuous temperature increase (global warming). However, a fraction of the increase (+0.3 °C corresponding to about 14% and +0.5 °C corresponding to about 25% for the entire year and the summer half-year, respectively) is attributed to the increase of global radiation. With regard to the brightening period in the last four decades (ca. 1982–2020), the fraction of the increase of global radiation within the total temperature increase is substantial: about one third for the entire year (ca. +0.6 °C), even half for the summer half-year (ca. +1.1 °C). The model results are reasonable in view of the comparison with the temperature measurements at the six stations. Increased air pollution by aerosols led to a continuous weakening of global radiation at the earth’s surface (global dimming) in Europe from about 1950–1980, but with the subsequent improvement of air quality, an increase occurred again (global brightening). Global brightening, which has continued until today, has more than compensated for global dimming of 1950–1980. From 1982–2020, direct solar radiation increased by about one-third in both the summer and winter months. This increase is about twice as large as the decrease during the dimming phase, except for the case of nearly overcast sky. The phases of global dimming and brightening are mainly caused on one hand by increasing and decreasing opacity of the atmosphere by aerosols, the direct aerosol effect. On the other hand, indirect radiative aerosol effects of cloud droplets, including effects of cloud properties, have had an increasing impact on global radiation.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141507618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of compact hygrometers for continuous airborne measurements","authors":"Christian Rolf, Susanne Rohs, Herman G.J. Smit, Martina Krämer, Zoltán Bozóki, Stefan Hofmann, Harald Franke, Rolf Maser, Peter Hoor, Andreas Petzold","doi":"10.1127/metz/2023/1187","DOIUrl":"https://doi.org/10.1127/metz/2023/1187","url":null,"abstract":"Continuous water vapour measurements in the troposphere and lowermost stratosphere are crucial for the understanding of global water transport processes and climate impact. In the course of the ‘Development and Evaluation of Novel and Compact Hygrometer for Airborne Research’ (DENCHAR) project, water vapour instruments (WaSuL, WVSS‑II, ICH) have been partly newly developed and/or extensively tested in the laboratory as well as onboard of research aircraft. For the blind intercomparisons of the instruments, an MBW DP30 frostpoint mirror and the established FISH Lyman‑α instrument (calibrated versus the MBW DP30) served as reference hygrometers in the laboratory and during the flights, respectively. All DENCHAR-instruments show very consistent behaviour in their respective measuring ranges with deviations of less than about 5–10 %, in‑flight with respect to FISH and in the laboratory with respect to DP30 in the range between 100 and 1000 ppmv, as well as among each other in the range of 100 to 20000 ppmv. At mixing ratios below 100 ppmv, differences between the instruments appear which depend on the individual response times and calibrations. In summary, the WaSul, ICH and WVSS‑II hygrometers can be recommended for continuous water vapour measurements at mixing ratios larger than 10, 30, and 30 ppmv, respectively. For an accurate, reliable, and stable measurement of lower water vapour mixing ratios with a compact hygrometer suitable for autonomous operation, either these instruments need to be improved or new technology would have to be developed. In addition to the instrument evaluation, the performance of different water vapour inlet systems is addressed by comparing a forward-facing Rosemount (TAT housing) and a wall plate inlet. From all in‑flight tests, no measurement artifacts caused by specific characteristics of an inlet could be identified, i.e., forward-facing Rosemount and wall plate inlets can be recommended for use on aircraft for water vapour mixing ratios above 30 ppmv.","PeriodicalId":49824,"journal":{"name":"Meteorologische Zeitschrift","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141507619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}