Improved fuzzy logic method to distinguish between meteorological and non-meteorological echoes using C-band polarimetric radar data

To obtain better performance of meteorological applications, it is necessary to distinguish radar echoes from meteorological and non-meteorological targets. After a comprehensive analysis of the computational efficiency and radar system characteristics, we propose a fuzzy logic method that is similar to the MetSignal algorithm; the performance of this method is improved significantly in weak-signal regions where polarimetric variables are severely affected by noise. In addition, post-processing is adjusted to prevent anomalous propagation at a far range from being misclassified as meteorological echo. Moreover, an additional fuzzy logic echo classifier is incorporated into post-processing to suppress misclassification in the melting layer. An independent test set is selected to evaluate algorithm performance, and the statistical results show an improvement in the algorithm performance, especially with respect to the classification of meteorological echoes in weak-signal regions

Pangu-Weather: A 3D High-Resolution Model for Fast and Accurate Global Weather Forecast

In this paper, we present Pangu-Weather, a deep learning based system for fast and accurate global weather forecast. For this purpose, we establish a data-driven environment by downloading $43$ years of hourly global weather data from the 5th generation of ECMWF reanalysis (ERA5) data and train a few deep neural networks with about $256$ million parameters in total. The spatial resolution of forecast is $0.25^\circ\times0.25^\circ$, comparable to the ECMWF Integrated Forecast Systems (IFS). More importantly, for the first time, an AI-based method outperforms state-of-the-art numerical weather prediction (NWP) methods in terms of accuracy (latitude-weighted RMSE and ACC) of all factors (e.g., geopotential, specific humidity, wind speed, temperature, etc.) and in all time ranges (from one hour to one week). There are two key strategies to improve the prediction accuracy: (i) designing a 3D Earth Specific Transformer (3DEST) architecture that formulates the height (pressure level) information into cubic data, and (ii) applying a hierarchical temporal aggregation algorithm to alleviate cumulative forecast errors. In deterministic forecast, Pangu-Weather shows great advantages for short to medium-range forecast (i.e., forecast time ranges from one hour to one week). Pangu-Weather supports a wide range of downstream forecast scenarios, including extreme weather forecast (e.g., tropical cyclone tracking) and large-member ensemble forecast in real-time. Pangu-Weather not only ends the debate on whether AI-based methods can surpass conventional NWP methods, but also reveals novel directions for improving deep learning weather forecast systems.Comment: 19 pages, 13 figures: the first ever AI-based method that outperforms traditional numerical weather prediction method

Comparison of Scanning LiDAR with Other Remote Sensing Measurements and Transport Model Predictions for a Saharan Dust Case

The evolution and the properties of a Saharan dust plume were studied near the city of Karlsruhe in southwest Germany (8.4298°E, 49.0953°N) from 7 to 9 April 2018, combining a scanning LiDAR (90°, 30°), a vertically pointing LiDAR (90°), a sun photometer, and the transport model ICON-ART. Based on this Saharan dust case, we discuss the advantages of a scanning aerosol LiDAR and validate a method to determine LiDAR ratios independently. The LiDAR measurements at 355 nm showed that the dust particles had backscatter coefficients of 0.86 ± 0.14 Mm$^{-1}$ sr$^{-1}$, extinction coefficients of 40 ± 0.8 Mm$^{-1}$, a LiDAR ratio of 46 ± 5 sr, and a linear particle depolarisation ratio of 0.27 ± 0.023. These values are in good agreement with those obtained in previous studies of Saharan dust plumes in Western Europe. Compared to the remote sensing measurements, the transport model predicted the plume arrival time, its layer height, and its structure quite well. The comparison of dust plume backscatter values from the ICON-ART model and observations for two days showed a correlation with a slope of 0.9 ± 0.1 at 355 nm. This work will be useful for future studies to characterise aerosol particles employing scanning LiDARs

Swabian MOSES 2021: An interdisciplinary field campaign for investigating convective storms and their event chains

The Neckar Valley and the Swabian Jura in southwest Germany comprise a hotspot for severe convective storms, causing tens of millions of euros in damage each year. Possible reasons for the high frequency of thunderstorms and the associated event chain across compartments were investigated in detail during the hydro-meteorological field campaign Swabian MOSES carried out between May and September 2021. Researchers from various disciplines established more than 25 temporary ground-based stations equipped with state-of-the-art in situ and remote sensing observation systems, such as lidars, dual-polarization X- and C-band Doppler weather radars, radiosondes including stratospheric balloons, an aerosol cloud chamber, masts to measure vertical fluxes, autosamplers for water probes in rivers, and networks of disdrometers, soil moisture, and hail sensors. These fixed-site observations were supplemented by mobile observation systems, such as a research aircraft with scanning Doppler lidar, a cosmic ray neutron sensing rover, and a storm chasing team launching swarmsondes in the vicinity of hailstorms. Seven Intensive Observation Periods (IOPs) were conducted on a total of 21 operating days. An exceptionally high number of convective events, including both unorganized and organized thunderstorms such as multicells or supercells, occurred during the study period. This paper gives an overview of the Swabian MOSES (Modular Observation Solutions for Earth Systems) field campaign, briefly describes the observation strategy, and presents observational highlights for two IOPs

Comparison of Scanning LiDAR with Other Remote Sensing Measurements and Transport Model Predictions for a Saharan Dust Case

The evolution and the properties of a Saharan dust plume were studied near the city of Karlsruhe in southwest Germany (8.4298°E, 49.0953°N) from 7 to 9 April 2018, combining a scanning LiDAR (90°, 30°), a vertically pointing LiDAR (90°), a sun photometer, and the transport model ICON-ART. Based on this Saharan dust case, we discuss the advantages of a scanning aerosol LiDAR and validate a method to determine LiDAR ratios independently. The LiDAR measurements at 355 nm showed that the dust particles had backscatter coefficients of 0.86 ± 0.14 Mm−1 sr−1, extinction coefficients of 40 ± 0.8 Mm−1, a LiDAR ratio of 46 ± 5 sr, and a linear particle depolarisation ratio of 0.27 ± 0.023. These values are in good agreement with those obtained in previous studies of Saharan dust plumes in Western Europe. Compared to the remote sensing measurements, the transport model predicted the plume arrival time, its layer height, and its structure quite well. The comparison of dust plume backscatter values from the ICON-ART model and observations for two days showed a correlation with a slope of 0.9 ± 0.1 at 355 nm. This work will be useful for future studies to characterise aerosol particles employing scanning LiDARs

Spatial distribution of aerosol particles in and above the planetary boundary layer studied by scanning LIDAR measurements

Die räumliche Verteilung von Aerosolpartikeln hat großen Einfluss auf die Luftverschmutzung durch anthropogene Emissionen aber auch auf das globale Klima, indem der Strahlungsantrieb entweder direkt oder über Aerosol-Wolken-Wechselwirkung verändert wird. Daher ist es unerlässlich, die räumlich-zeitliche Verteilung von Aerosolpartikeln und die Prozesse, die zu diesen Verteilungen führen (z. B. Quellen, Senken und Transport), zu untersuchen. Derzeit ist es aufgrund instrumenteller Einschränkungen noch schwierig, hochauflösende und quantitative Aerosolverteilungen zu erhalten. Schwenkbare Aerosol-Lidare sind jedoch in der Lage, dreidimensionale Aerosolverteilungen zu messen und Auswerteunsicherheiten im Vergleich zu herkömmlichen, vertikal ausgerichteten Lidaren zu verringern. Das in dieser Dissertation verwendete schwenkbare Aerosol-Lidar ermöglichte es mir daher, hochaufgelöste und quantitative Aerosolverteilungen zu bestimmen. Diese Lidardaten helfen zusammen mit anderen Messungen, Aerosol-Grenzschicht-Wechselwirkungen sowie Aerosol-Wolken-Wechselwirkungen besser zu verstehen. Zur Untersuchung der räumlich-zeitlichen Verteilung und Eigenschaften von Aerosolen sowie der Grenzschichtdynamik wurde ein umfangreicher Datensatz mit Fernerkundungsmethoden, in-situ-Messungen in Bodennähe sowie mit Drohnenflügen (UAV) und auf Ballons gesammelt und analysiert . Darüber hinaus habe ich diese Beobachtungsdaten verwendet um zwei Transportmodelle zu validieren. Das LES-Model PALM-4U, das die Entwicklung der Grenzschicht und des städtischen Aerosols in der Stadt Stuttgart simuliert und das Transportmodell ICON-ART, das den überregionalen Transport von Saharastaub beschreibt. Zunächst habe ich eine neue Methode entwickelt, um Lidar-Verhältnisse auf der Grundlage von Lidar-Messungen unter mindestens zwei verschieden Winkel abzuleiten, was die Unsicherheiten gegenüber traditionellen Methoden erheblich verringern könnte. Die neu vorgeschlagene Methode wurde für eine Saharastaubwolke angewendet und das abgeleitete Lidar-Verhältnis stimmt mit dem überein, das durch die klassische Raman-Methode erhalten wurde. Darüber hinaus habe ich die Lidarauswertung durch Vergleich mit in-situ-Messungen auf Bodenhöhe, bei Drohnenflügen in und über der Grenzschicht, sowie auf einem Ballonflug in die Stratosphäre validiert. Die gute Übereinstimmung zwischen Auswertungen mit der neu entwickelten Software und der Single-Calculus-Chain-Referenzsoftware sowie den in-situ-Messungen ist ein klarer Indikator für die hohe Qualität der Lidar-Messdaten und der verwendeten Methodik. Zweitens wurde die Dynamik der städtischen Grenzschicht und die Luftqualität im städtischen Hintergrund von Stuttgart charakterisiert. Dazu habe ich Daten des schwenkbaren Lidars mit einem Doppler-Wind-Lidar, einem Radiometer, Radiosonden sowie einer Sammlung von bodennahen in-situ-Methoden (Größenverteilungen, Meteorologische Parameter, Aerosolzusammensetzung) verglichen. Die vom schwenkbaren Aerosol-Lidar gemessene Grenzschichtstruktur zeigt eine gute Übereinstimmung mit der Radiosondenanalyse mit einer Steigung der Korrelation von 1,102 $\pm$ 0,135 und einem Pearson-Korrelationskoeffizienten von 0,860. Die bodennahen Aerosolkonzentrationen korrelieren dabei mit den Mischungschichthöhen, aber sind antikorreliert mit den nächtlichen Grenzschichthöhen. Stagnierende atmosphärische Bedingungen mit Temperaturinversion, geringer Windgeschwindigkeit und einer flachen Grenzschicht führten zu einer Ansammlung von bodennahen Aerosolen insbesondere im Winter. Dies ist einer der Hauptgründe für die hohe Luftverschmutzung in Städten wie Stuttgart. In einer Fallstudie konnte ich zeigen, dass Wolken in einer vorangegangenen Nacht das Wachstum der Grenzschicht nach Sonnenaufgang beschleunigen können, indem sie die thermische Struktur der nächtlichen Grenzschicht verändern. Darüber hinaus verwende ich die Beobachtungsdaten zur Validierung des Large-Eddy-Simulationsmodells PALM-4U, dass die Entwicklung der Grenzschicht und die räumlich-zeitliche Verteilung von Aerosolen in diesem Stadtgebiet mit einer räumlichen Auflösung von 10 m simuliert. Drittens habe ich die Entwicklung und die Eigenschaften einer Saharastaubwolke untersucht, wobei Fernerkundungsmethoden (Aerosol-Lidar, Sonnenphotometer), in-situ-Messungen (Aerosolgrößenverteilungen) und das Transportmodell ICON-ART für vier verschiedene Saharastaubfälle in Westeuropa kombiniert wurden. Im Vergleich zu den Fernerkundungsmessungen sagt das Transportmodell die Ankunftszeiten der Wolke ($\pm$ 20 min), ihre Schichthöhen ($\pm$ 50 m) und Strukturen für drei Fälle recht gut voraus, während für einen Fall signifikante Unterschiede in der Staubschichthöhe beobachtet wurden. Die modellierten Rückstreukoeffizienten des Staubs zeigen unter der Annahme von nicht kugelförmigen Staubpartikeln eine gute Übereinstimmung mit Lidardaten für eine Wellenlänge von 355 nm. Außerdem fand ich erste Hinweise darauf, dass Saharastaubfahnen niederschlagshemmend wirken können. Ich habe in dieser Dissertation die Grenzschichtdynamik und die räumlich-zeitlichen Verteilungen von Aerosolpartikeln hauptsächlich unter Verwendung eines schwenkbaren Aerosol-Lidars untersucht. Die Informationen zu den räumlich-zeitlichen Aerosolverteilungen ermöglichten es mir, Aerosoleigenschaften und die Entwicklung der atmosphärischen Grenzschicht in städtischen und ländlichen Gebieten im Winter bzw. Sommer zu untersuchen. Diese Arbeit liefert neue Einblicke in die Anwendung des schwenkbaren Aerosol-Lidars, in die Qualität seiner Daten, in die Dynamik der bodennahen Grenzschicht, in die Qualität der Modelle ICON-ART und zukünftig PALM-4U, sowie zu Aerosolverteilung und deren Auswirkungen auf Luftqualität, Wetter und Klima

Circ_0110251 overexpression alleviates IL-1β-induced chondrocyte apoptosis and extracellular matrix degradation by regulating miR-3189-3p/SPRY1 axis in osteoarthritis

Background Mounting evidence indicates that circular RNAs (circRNAs) are involved in the progression of human diseases, including osteoarthritis (OA). In this study, we focussed on the functions and potential mechanism of circ_0110251 in OA. Methods Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine the expression of circ_0110251, collagen type XI alpha 1 chain (COL11A1), microRNA-3189-3p (miR-3189-3p) and sprouty receptor tyrosine kinase signalling antagonist 1 (SPRY1). The cyclisation analysis of circ_0110251 was analysed by RNase R and Actinomycin D assays. Flow cytometry analysis was conducted to analyse cell apoptosis. Western blot assay was used to measure the levels of extracellular matrix degradation (ECM)-associated markers and SPRY1. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull down assay were performed to analyse the relationships among circ_0110251, miR-3189-3p and SPRY1. Results Circ_0110251 was downregulated in OA cartilage tissues and IL-1β-induced chondrocytes. IL-1β promoted the apoptosis and ECM degradation in chondrocytes, while circ_0110251 overexpression relieved the effects. Circ_0110251 functioned as the sponge for miR-3189-3p and miR-3189-3p overexpression reversed the effect of circ_0110251 on IL-1β-induced chondrocyte damage. Additionally, SPRY1 served as the target gene of miR-3189-3p. MiR-3189-3p inhibition ameliorated IL-1β-induced chondrocyte apoptosis and ECM degradation, while SPRY1 silencing rescued the impacts. Conclusion Circ_0110251 protected chondrocytes from IL-1β-induced apoptosis and ECM degradation in OA via sponging miR-3189-3p and elevating SPRY1

Soil nitrogen and its fractions between long-term conventional and no-tillage systems with straw retention in dryland farming in northern China

Knowledge about the changes in soil nitrogen pools under different tillage managements is necessary to assess the feasibility of adoption of conservation practices for sustaining productivity and protecting the environment in dryland farming in northern China. We investigated the long-term effects (22 years) of no-till with residue retention (NTR) on total soil N and its fractions in a dry-land winter wheat (Triticum aestivum L.) cropping system in northern China. Compared with conventional tillage without residue retention (CT), significantly higher soil total N (STN) concentrations were observed in the surface soil layer (0–10 cm) under NTR. Meanwhile, more soil N accumulated for the whole soil profile (0 to 60 cm) in the NTR (3.38 Mg ha− 1) treatment relative to the CT (3.17 Mg ha− 1) treatment. The particulate organic matter N (PON), microbial biomass N (MBN), and water extractable organic N (WEON) levels in the NTR treatments were 52.3%, 116%, and 69.4% greater at a depth of 0–5 cm and 41.6%, 108%, and 44.9% greater at a depth of 5–10 cm, respectively, compared with the CT treatment. However, no differences were observed below the 10 cm layer. At a depth of 0–60 cm, the soil NH4-N content under CT was higher than that under NTR. However, the soil NO3-N contents in the NTR treatments were significantly greater at a depth of 0–10 cm and were not significantly different at a depth of 10–60 cm, relative to the CT treatment. Significantly positive correlations were observed between the STN and the labile organic N fractions. Overall, the results show that no-till coupled with residue retention is an effective management method for improving soil N stocks and increasing soil fertility. Nonetheless, other benefits associated with NT and residue retention present greater challenges regarding their popularization and application in the dryland farming areas in northern China