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Precipitation is arguably one of the most relevant surface variables impacting human lives on the planet, but global-coverage, high-resolution and good-quality observations are not readily available. In particular, gridded observational datasets are much needed for model development and forecast quality assessment. Here we compare the quality of four types of gridded precipitation products over Europe, namely: a rain-gauge interpolation; a satellite-derived product; a radar composite; and a reanalysis. Each product has its own strengths and weaknesses, and since each precipitation estimate uses different measuring techniques, we can employ a triangulation method to estimate the error variance of each product with respect to the unknown true values. Results show that: a) the satellite product has limited quality over Europe and may be problematic to use in quantitative forecast evaluation and diagnostics; b) the radar composite has spurious features that need to be considered when used in verification; c) all products struggle in topographically complex areas; d) the rain-gauge interpolation is not free of errors, despite rain gauges being often treated as ground truth in the literature; and e) the reanalysis dataset produces in some cases the best available estimates, in particular over the European near-coastal waters. [ABSTRACT FROM AUTHOR]

Ground-based radar precipitation products typically need adjustment with rain gauge accumulations to achieve a reasonable accuracy. This is certainly the case for the pan-European radar precipitation products. The density of (near) real-time rain gauge accumulations from official networks is often relatively low. Crowdsourced rain gauge networks have a much higher density than conventional ones and are a potentially interesting (complementary) source to merge with radar precipitation accumulations. Here, a 1-year personal weather station (PWS) rain gauge dataset of ∼ 5 min accumulations is obtained from the private company Netatmo over the period 1 September 2019–31 August 2020, which is subjected to quality control using neighbouring PWSs and, after aggregating to 1 h accumulations, using unadjusted radar data. The PWS 1 h gauge accumulations are employed to spatially adjust OPERA radar accumulations, covering 78 % of geographical Europe. The performance of the merged dataset is evaluated against daily and disaggregated 1 h gauge accumulations from weather stations in the European Climate Assessment & Dataset (ECA&D). Results are contrasted to those from an unadjusted OPERA-based radar dataset and from EURADCLIM. The severe average underestimation for daily precipitation of ∼ 28 % from the unadjusted radar dataset diminishes to ∼ 3 % for the merged radar–PWS dataset. A station-based spatial verification shows that the relative bias in 1 h precipitation is still quite variable and suggests stronger underestimations for colder climates. A dedicated evaluation with scatter density plots reveals that the performance is indeed less good for lower temperatures, which points to limitations in observing solid precipitation by PWS gauges. The outcome of this study confirms the potential of crowdsourcing to improve radar precipitation products in (near) real time. [ABSTRACT FROM AUTHOR]

The recent release of European Ground Motion Service (EGMS) products implemented under the responsibility of the Copernicus Land Monitoring Service (CLMS) guarantees free and accessible Europe-wide ground motion data for ground deformation analysis at the local and regional scales. The need for value-adding services and tools for optimal dissemination of radar data from the Copernicus Sentinel-1 satellite mission urges the scientific community to find efficient solutions. A desktop R-based application with a user-friendly interface capable of automatically downloading and transforming EGMS products delivered as large.csv tiles, equivalent to a radar burst into geospatial databases, is presented here. EGMStream is a self-contained desktop app that enables users to systematically store, customize, and convert ground movement data into geospatial databases, burst per burst or for an area of interest directly selectable on the app interface. [ABSTRACT FROM AUTHOR]

• A review of track detection algorithms across different research fields. • Technical description of the initiation, maintenance and termination of a radar track in the BIRALES radar. • Presentation of a new track detection strategy that is used for the detection of orbital debris using a bi-static continuous-wave radar. • Performance evaluation of this new track detection method on synthetic data. The world's economy has become heavily dependent on the services provided by satellites. With the exponential increase in satellite launches, the population of defunct or inactive hardware in space has grown substantially. This is especially true in sensitive orbits such as the Low Earth Orbit (LEO) and Geostationary Earth Orbit (GEO) regimes. These objects, collectively known as orbital debris, can reach speeds of up to 28 000km h−1 in LEO. At these orbital speeds, even the smallest of objects can pose a considerable threat to operational satellites or astronauts. This makes the monitoring, and detection, of these objects of the utmost importance. This work describes the latest detection strategy used in one of Europe's largest Space Situational Awareness (SSA) installation; the BIstatic RAdar for LEo Survey (BIRALES) space debris radar. We present a novel bottom-up approach that makes use of single-linkage clustering to identify faint radar streaks in spectrogram data. Tests on synthetic data have shown that the detection strategy presented in this study obtains a higher detection rate when it is compared against existing methods. Unlike other approaches, this detection strategy, using the Multi-beam streak detection strategy (MSDS) algorithm, was still able to recall 90% of the track information at an Signal-to-Noise Ratio (SNR) of 2dB. [ABSTRACT FROM AUTHOR]

The European climatological high-resolution gauge-adjusted radar precipitation dataset, EURADCLIM, addresses the need for an accurate (sub-)daily precipitation product covering 78% of Europe at high spatial resolution. A climatological dataset of 1-h and 24-h precipitation accumulations on a 2-km grid is derived for the period 2013 through 2020. The starting point is the European Meteorological Network (EUMETNET) Operational Program on the Exchange of weather RAdar Information (OPERA) gridded radar dataset of 15-min instantaneous surface rain rates, which is based on data from, on average, 138 ground-based weather radars. First, methods are applied to further remove non-meteorological echoes from these composites by applying two statistical methods and a satellite-based cloud type mask. Second, the radar composites are merged with the European Climate Assessment & Dataset (ECA&D) with potentially ~7700 rain gauges from National Meteorological and Hydrological Services (NMHS) in order to substantially improve its quality. Characteristics of the radar, rain gauge and satellite datasets are presented, as well as a detailed account of the applied algorithms. The clutter removal algorithms are effective, while removing few precipitation echoes. The usefulness of EURADCLIM for quantitative precipitation estimation (QPE) is confirmed by comparing against rain gauge accumulations employing scatter density plots, statistical metrics, and a spatial verification. These show a strong improvement with respect to the original OPERA product. The potential of EURADCLIM to derive pan-European precipitation climatologies and to evaluate extreme precipitation events is shown. Specific attention is given to remaining artefacts in and limitations of EURADCLIM. Finally, it is recommended to further improve EURADCLIM by applying algorithms to 3D instead of 2D radar data, and by obtaining more rain gauge data for the radar-gauge merging. The EURADCLIM 1-h and 24-h precipitation datasets are publicly available at https://doi.org/10.21944/7ypj-wn68 (Overeem et al., 2022a) and https://doi.org/10.21944/1a54-gg96 (Overeem et al., 2022b). [ABSTRACT FROM AUTHOR]

A chronological synopsis of the history of the technology used in experimental and testing work relating to artillery pieces is presented. The period covered is from the mid-seventeenth century up to the Cold War era of the mid-twentieth century. Although the focus is on the development of ballistics measurement in Britain, there are important links to related work in continental Europe. The locus for much of what is described is the Royal Artillery proof and experimental range at Shoeburyness and the key individuals and groups of men and women who worked there. There are longitudinal connections between the very earliest technologies of mechanical chronometry, with paper screens and paper-based calculations, and the later technology where timings, screens and calculations had all become electronic. [ABSTRACT FROM AUTHOR]

• The quality of OPERA radar precipitation composites is assessed during 2015–2017. • SYNOP gauges records over Europe are used as reference and to adjust OPERA rainfall. • 3 years analysis shows improvement in the radar composites after rain gauge adjustment. • The daily monitoring shows gradual improvements of the OPERA composite itself. • Adjusted OPERA composites are useful for pan-European flash flood hazard assessment. Monitoring continental precipitation over Europe with high resolution (2 km, 15 min) has been possible since the operational production of the OPERA composites from the European weather radar networks. The OPERA data are the essential input to a hazard assessment tool for identifying localized rainfall-induced flash floods at European scale, and their quality determines the performance of the tool. This paper analyses the OPERA data quality during the warm seasons of 2015–2017 by comparing the estimated rainfall accumulations with the SYNOP rain gauge records over Europe. To compensate the OPERA underestimation, a simple spatially-variable bias adjustment method has been applied. The long-term comparison between the OPERA and gauge point daily rainfall accumulations at the gauge locations shows the benefit of the bias adjustment. Additionally, the daily monitoring shows gradual improvement of the OPERA data year by year. The impact of the quality of the OPERA data for effective flash flood identification is demonstrated for the case of the flash floods that occurred from 29 May to 3 June 2016 in central Europe. [ABSTRACT FROM AUTHOR]

The aerosphere is utilized by billions of birds, moving for different reasons and from short to great distances spanning tens of thousands of kilometres. The aerosphere, however, is also utilized by aviation which leads to increasing conflicts in and around airfields as well as en‐route. Collisions between birds and aircraft cost billions of euros annually and, in some cases, result in the loss of human lives. Simultaneously, aviation has diverse negative impacts on wildlife. During avian migration, due to the sheer numbers of birds in the air, the risk of bird strikes becomes particularly acute for low‐flying aircraft, especially during military training flights. Over the last few decades, air forces across Europe and the Middle East have been developing solutions that integrate ecological research and aviation policy to reduce mutual negative interactions between birds and aircraft. In this paper we 1) provide a brief overview of the systems currently used in military aviation to monitor bird migration movements in the aerosphere, 2) provide a brief overview of the impact of bird strikes on military low‐level operations, and 3) estimate the effectiveness of migration monitoring systems in bird strike avoidance. We compare systems from the Netherlands, Belgium, Germany, Poland and Israel, which are all areas that Palearctic migrants cross twice a year in huge numbers. We show that the en‐route bird strikes have decreased considerably in countries where avoidance systems have been implemented, and that consequently bird strikes are on average 45% less frequent in countries with implemented avoidance systems in place. We conclude by showing the roles of operational weather radar networks, forecast models and international and interdisciplinary collaboration to create safer skies for aviation and birds. [ABSTRACT FROM AUTHOR]

Large parts of the continents are continuously scanned by terrestrial weather radars to monitor precipitation and wind conditions. These systems also monitor the mass movements of bird, bat, and insect migration, but it is still unknown how many of these systems perform with regard to detection and quantification of migration intensities of the different groups. In this study that was undertaken within five regions across Europe and the Middle East we examined to what extent bird migration intensities derived from different weather radars are comparable between each other and relate to intensities measured by local small‐scaled radars, some of them specifically developed to monitor birds. Good correspondence was found for the relative day‐to‐day pattern in migration intensities among most radar systems that were compared. Absolute intensities varied between different systems and regions. The findings of this study can be used to infer about absolute bird migration intensities measured by different radar systems and consequently help resolving methodological issues regarding the estimation of migrant numbers in the Western‐Palearctic region. It further depicts a scientific basis for the future monitoring of migratory bird populations across a large spatio‐temporal scale, predicting their movements and studying its consequences on ecological systems and human lives. [ABSTRACT FROM AUTHOR]

This study gives a summary of lessons learned during the absolute calibration of the airborne, high-power Ka-band cloud radar HAMP MIRA on board the German research aircraft HALO. The first part covers the internal calibration of the instrument where individual instrument components are characterized in the laboratory. In the second part, the internal calibration is validated with external reference sources like the ocean surface backscatter and different air- and spaceborne cloud radar instruments. A key component of this work was the characterization of the spectral response and the transfer function of the receiver. In a wide dynamic range of 70 dB , the receiver response turned out to be very linear (residual 0.05 dB). Using different attenuator settings, it covers a wide input range from -105 to -5 dBm. This characterization gave valuable new insights into the receiver sensitivity and additional attenuations which led to a major improvement of the absolute calibration. The comparison of the measured and the previously estimated total receiver noise power (-95.3 vs. -98.2 dBm) revealed an underestimation of 2.9 dB. This underestimation could be traced back to a larger receiver noise bandwidth of 7.5 MHz (instead of 5 MHz) and a slightly higher noise figure (1.1 dB). Measurements confirmed the previously assumed antenna gain (50.0 dBi) with no obvious asymmetries or increased side lobes. The calibration used for previous campaigns, however, did not account for a 1.5 dB two-way attenuation by additional waveguides in the airplane installation. Laboratory measurements also revealed a 2 dB higher two-way attenuation by the belly pod caused by small deviations during manufacturing. In total, effective reflectivities measured during previous campaigns had to be corrected by +7.6 dB. To validate this internal calibration, the well-defined ocean surface backscatter was used as a calibration reference. With the new absolute calibration, the ocean surface backscatter measured by HAMP MIRA agrees very well (<1 dB) with modeled values and values measured by the GPM satellite. As a further cross-check, flight experiments over Europe and the tropical North Atlantic were conducted. To that end, a joint flight of HALO and the French Falcon 20 aircraft, which was equipped with the RASTA cloud radar at 94 GHz and an underflight of the spaceborne CloudSat at 94 GHz were performed. The intercomparison revealed lower reflectivities (-1.4 dB) for RASTA but slightly higher reflectivities (+1.0 dB) for CloudSat. With effective reflectivities between RASTA and CloudSat and the good agreement with GPM, the accuracy of the absolute calibration is estimated to be around 1 dB. [ABSTRACT FROM AUTHOR]

Knotweeds were introduced into Europe in the 19th century and soon after became aggressive invaders. While R. japonica and R. sachalinensis arrived from Asia, their hybrid Reynoutria × bohemica is believed to originate from the introduced range. Revised material shows that R. × bohemica has occurred in Europe since at least 1872, but was frequently misidentified as one of the parents. For that reason, the hybrid was detected relatively late in many European countries, meaning that it was silently spreading throughout the region for a long time. The present study was conducted in Croatia, where the parental species have been recorded since the 19th century, the hybrid, however, not being recognized until very recently, although it has probably been present for decades. As a result, the current knowledge of the distribution of knotweeds in Croatia is mostly erroneous. We revised specimens from Croatian herbaria and performed an extensive field survey across the whole of the territory of Croatia to collect new data. In this paper, we present accurate distribution maps of the three taxa, produced after a thorough revision, showing a result remarkably different to that previously known. In contrast to previously recorded distributions, we found that R. × bohemica is by far the most widespread, R. japonica is occasional, and R. sachalinensis is extremely rare. R. × bohemica, unlike its parents, occurs in Mediterranean Croatia as well. Compared to R. × bohemica, R. japonica occurs more frequently along watercourses. Taking into account that the studied taxa have different behaviour, ecological preferences, spreading ability and consequently different invasiveness, they should be analysed separately in any attempt to explain, manage and/or limit their spread. Therefore, the accuracy of their past and future identification is of major importance. [ABSTRACT FROM AUTHOR]

• Burn severity decreases in WUIs proportionally to nearby building aggregation. • The combination of radar and multispectral variables is useful to predict burn severity. • Variables related to the amount of living vegetation are the most important to predict burn severity. • Burn severity is more predictable outside WUIs than inside them. • Knowledge of burn severity drivers serves to improve landscape planning in WUIs. Fire danger analysis is crucial for landscape planning, which is particularly relevant in vulnerable areas such as the wildland-urban interface (WUI). The aim of our work is to investigate the capacity of fuel characteristics to predict burn severity in different WUI typologies classified according to nearby building density criteria. To achieve this goal, we selected 23 wildfires across Southern Europe, in which we differentiated non WUI areas, isolated, scattered, dense and very dense WUIs. Moreover, we spatialized burn severity and different fuel metrics using multispectral and radar satellite imagery. This information was used to analyze burn severity, and to identify its drivers in the different WUI typologies through analysis of variance, correlation analysis and machine learning models. Our results indicate that burn severity is lower in WUIs of clustered buildings than in non-WUI areas, which were also the most homogeneous in terms of vegetation cover. Moreover, we found that vegetation biophysical properties related to the amount of living fuel (fraction of vegetation cover and fraction of absorbed photosynthetically active radiation) showed the highest influence on burn severity in all WUI typologies. We also found that burn severity is less predictable in dense and very dense WUIs than in the rest, which can be attributed to their greater landscape complexity, presence of artificial structures and efficiency of extinction efforts. Our results serve to guide landscape management strategies, and impulse next-generation fire danger models, which should be based not only on synoptic fire weather indices but also on landscape-scale susceptibility to severe fires. [ABSTRACT FROM AUTHOR]

Clouds cover substantial parts of the Earth's surface and they are one of the most essential components of the global climate system impacting the Earth's radiation balance as well as the water cycle redistributing water around the globe as precipitation. Therefore, continuous observation of clouds is of primary interest in climate and hydrological studies. This work documents the first efforts in Italy in remote sensing clouds and precipitation using a combination of K- and W-band (24 and 94 GHz, respectively) radar profilers. Such a dual-frequency radar configuration has not been widely used yet, but it could catch on in the near future given its lower initial cost and ease of deployment for commercially available systems at 24 GHz, with respect to more established configurations. A field campaign running at the Casale Calore observatory at the University of L'Aquila, Italy, nestled in the Apennine mountain range is described. The campaign features are preceded by a review of the literature and the underpinning theoretical background that might help newcomers, especially in the Italian community, to approach cloud and precipitation remote sensing. This activity takes place in interesting time for radar sensing clouds and precipitation, stimulated both by the launch of the ESA/JAXA EarthCARE satellite missions scheduled in 2024, which will have on-board, among other instruments, a W-band Doppler cloud radar and the proposal of new missions using cloud radars currently undergoing their feasibility studies (e.g., WIVERN and AOS in Europe and Canada, and U.S., respectively).

This paper analyzes the flood that occurred between 11th and 13th of September 2013 in the upper catchment of the river Geru. The flood was simulated using the program Mike by DHI with the Unitary Hydrograph Method. As input data, we used the precipitation measured at the Automated Hydrological Sensor Station Cudalbi and radar precipitations. We analyzed the importance of accuracy for input data on the simulation results and the direct influence of setting the proper time steps in achieving the simulated discharge hydrograph. It appears that radar precipitations used as input data lead to a discharge hydrograph with low errors for amplitude and phase of the runoff peak. The model can be used in the future to reproduce the floods produced in the analyzed catchment and to study the influence of physical and geographical characteristics of the hillslopes. [ABSTRACT FROM AUTHOR]

More than five decades after World War ii and two decades since the end of the cold War and its corresponding threat of nuclear annihilation, existential security concerns seem far from the minds of average Europeans. This sense of safety, combined with tight government budgets in a time of economic crisis, makes costly weapons systems and other defense expenditures seem less essential to citizens and policymakers alike. But despite the impression of security, europe cannot afford to be complacent to continued threats in a still-dangerous world. While the cold War danger of global nuclear war has receded, the risk of missile-borne nuclear attack remains. At the 2010 NATO Summit in Lisbon, Ballistic Missile Defense (BMD) was designated a core element of NATO's collective defense requirements and the Alliance committed "to expand NATO's current system to protect NATO-deployed forces to also protect NATO European populations and territory." And at the 2012 NATO Summit in Chicago, the Alliance confirmed its strategic and financial commitment. NATO defense and intelligence communities consider the ongoing ballistic missile and nuclear weapons development efforts of regional actors such as North Korea to be legitimate security threats. Many NATO and European Union officials are concerned that the ongoing economic crisis may deter European nations from fulfilling their basic obligation to protect their people and territories from nuclear attack. [ABSTRACT FROM AUTHOR]

Insect migration needs to be quantified if spatial and temporal patterns in populations are to be resolved. Yet so little ecology is understood above the flight boundary layer (i.e. >10 m) where in north-west Europe an estimated 3 billion insects km-1 month-1 comprising pests, beneficial insects and other species that contribute to biodiversity use the atmosphere to migrate. Consequently, we elucidate meteorological mechanisms principally related to wind speed and temperature that drive variation in daytime aerial density and insect displacements speeds with increasing altitude (150-1200 m above ground level). We derived average aerial densities and displacement speeds of 1.7 million insects in the daytime convective atmospheric boundary layer using vertical-looking entomological radars. We first studied patterns of insect aerial densities and displacements speeds over a decade and linked these with average temperatures and wind velocities from a numerical weather prediction model. Generalized linear mixed models showed that average insect densities decline with increasing wind speed and increase with increasing temperatures and that the relationship between displacement speed and density was negative. We then sought to derive how general these patterns were over space using a paired site approach in which the relationship between sites was examined using simple linear regression. Both average speeds and densities were predicted remotely from a site over 100 km away, although insect densities were much noisier due to local 'spiking'. By late morning and afternoon when insects are migrating in a well-developed convective atmosphere at high altitude, they become much more difficult to predict remotely than during the early morning and at lower altitudes. Overall, our findings suggest that predicting migrating insects at altitude at distances of ≈100 km is promising, but additional radars are needed to parameterise spatial covariance. [ABSTRACT FROM AUTHOR]

Abstract: Drawing on the results of a study that uses Pinkfroot''s Plane Finder HD flight radar app for the iPad to document the utilisation rates of eight A320-200 airframes that were operated by four European airlines during January 2012, the paper assesses the potential for using flight radar apps as a source of empirical data to inform academic research. The paper discusses the potential benefits and drawbacks of using consumer flight radar apps for scholarly research and makes recommendations for how these new sources of flight data might be employed. [Copyright &y& Elsevier]

Strategic as well as operational management of all kind needs a specific toolset of steering instruments to achieve the defined business targets. Business controlling, as this management task is mainly called in Europe, is definitely required in complex situations like reaching for real sustainability. A steering cycle with clear targets, planning and achievement measurements, and actively steering with counter-measures is the basic instrument of business controlling. But the scope has to be enlarged, the indicators need to be changed and further instruments have to be introduced, to focus the business activities on the well-balanced interests of all stakeholders of the company. Sustainable management and business controlling is based on clear personal values of the acting people. Strategic targets derived from these values and consequent operational actions build a new management system together. The core business figures indicate the contribution of a company to the welfare of all of its stakeholders. [ABSTRACT FROM AUTHOR]

Current strategic plans for air traffic management (ATM) envisage a transition from radar control to a trajectory-based system. The future ATM concepts are very different in a great number of aspects from the present system. The focus here is on the design of safe systems, in particular the appropriate air traffic control (ATC) separation minima. This Part 1 sketches the historical origins of ATC separation minima and then analyses the safety thinking behind current minima and the issues involved in risk modelling. Why have the critical minima largely remained unchanged for several decades – stasis? Part 2 then addresses key safety issues in the transition to the new ATM concept.‘Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.’ Archimedes. [ABSTRACT FROM PUBLISHER]

Functioning ecosystems offer multiple services for human well-being (e.g., food, freshwater, fiber). Agriculture provides several of these services but also can cause negative impacts. Thus, it is essential to derive up-to-date information about agricultural land use and its change. This paper describes the multi-temporal classification of agricultural land use based on high resolution spotlight TerraSAR-X images. A stack of 14 dual-polarized radar images taken during the vegetation season have been used for two different study areas (North of Germany and Southeast Poland). They represent extremely diverse regions with regard to their population density, agricultural management, as well as geological and geomorphological conditions. Thereby, the transferability of the classification method for different regions is tested. The Maximum Likelihood classification is based on a high amount of ground truth samples. Classification accuracies differ in both regions. Overall accuracy for all classes for the German area is 61.78% and 39.25% for the Polish region. Accuracies improved notably for both regions (about 90%) when single vegetation classes were merged into groups of classes. Such regular land use classifications, applicable for different European agricultural sites, can serve as basis for monitoring systems for agricultural land use and its related ecosystems. [ABSTRACT FROM AUTHOR]

Since the early 1990s, marine wind farms have become a reality, with at least 13 000 offshore wind turbines currently proposed in European waters. There are public concerns that these man-made structures will have a significant negative impact on the many bird populations migrating and wintering at sea. We assess the degree of usefulness and the limitations of different remote technologies for studying bird behaviour in relation to bird–turbine collisions at offshore wind farms. Radar is one of the more powerful tools available to describe the movement of birds in three-dimensional space. Although radar cannot measure bird–turbine collisions directly, it offers the opportunity to quantify input data for collision models. Thermal Animal Detection System (TADS) is an infra red-based technology developed as a means of gathering highly specific information about actual collision rates, and also for parameterizing predictive collision models. TADS can provide information on avoidance behaviour of birds in close proximity to turbine rotor-blades, flock size and flight altitude. This review also assesses the potential of other (some as yet undeveloped) techniques for collecting information on bird flight and behaviour, both pre- and post-construction of the offshore wind farms. These include the use of ordinary video surveillance equipment, microphone systems, laser range finder, ceilometers and pressure sensors. [ABSTRACT FROM AUTHOR]

This paper describes the first comparison performed in Europe between the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) and a (C-band) ground-based radar. The scope of the research is within the research activities of VOLTAIRE, a European Commission project. Notwithstanding the time lag and differences in the frequency of operation, sample volume. geometrical viewing angles, attenuation and radar sensitivity, there Is a reasonable agreement between the two sensors (∼ 1-2 dBZ). Ground-based and space-borne radar measurements provide a complementary view of such a complex phenomenon like We precipitation field. [ABSTRACT FROM AUTHOR]

Airspace is a key but not well-understood habitat for many animal species. Enormous amounts of insects and birds use the airspace to forage, disperse, and migrate. Despite numerous studies on migration, the year-round flight activities of both birds and insects are still poorly studied. We used a 2 year dataset from a vertical-looking radar in Central Europe and developed an iterative hypothesis-testing algorithm to investigate the general temporal pattern of migratory and local movements. We estimated at least 3 million bird and 20 million insect passages over a 1 km transect annually. Most surprisingly, peak non-directional bird movement intensities during summer were of the same magnitude as seasonal directional movement peaks. Birds showed clear peaks in seasonally directional movements during day and night, coinciding well with the main migration period documented in this region. Directional insect movements occurred throughout the year, paralleling non-directional movements. In spring and summer, insect movements were non-directional; in autumn, their movements concentrated toward the southwest, similar to birds. Notably, the nocturnal movements of insects did not appear until April, while directional movements mainly occurred in autumn. This simple monitoring reveals how little we still know about the movement of biomass through airspace. [ABSTRACT FROM AUTHOR]

This article describes the development of experimental work on ionospheric tomography carried out in Europe. It starts with early two-station observations and discusses the recent complex coordinated campaigns that have involved ionosondes to determine the bottomside profile and incoherent scatter radar to verify the image. [ABSTRACT FROM AUTHOR]

Millions of bird observations have been entered on online portals in the past 20 years either as checklists or arbitrary individual entries. While several hundred publications have been written on a variety of topics based on bird checklists worldwide, unstructured non-checklist observations have received little attention and praise by academia. In the present study we tested the suitability of non-checklist data to estimate key figures of large-scale migration phenology in four zones covering the whole of Finland. For that purpose, we analysed 10 years of ornithological non-checklist data including over 400 million. individuals of 115 bird species. We discuss bird- and human-induced effects to be considered in handling non-checklist data in this context and describe applied methodologies to address these effects. We calculated 5%, 50% and 95% percentile dates of spring and autumn migration period for all species in all four zones. For validation purposes we compared the temporal distributions of 43 bird species with migration phenology from standardized long-term ringing data in autumn of which 24 species (56%) showed similar medians. In a model approach, non-checklist data successfully revealed latitudinal migration progression in spring and autumn. Overall, non-checklist data proved to be well suited to determine descriptors of migration phenology in Northern Europe which are challenging to attain by any other currently available means. The effort-to-yield ratio of data processing was commensurate to the outcomes. The unprecedented spatiotemporal coverage makes non-checklist data a valuable complement to current migration databases from bird observatories. The basic concept of the present methodology is applicable to data from other bird portals, if combined with local field ornithological knowledge and literature. Species-specific descriptors of migration phenology can be potentially used in climate change studies and to support echo interpretation in radar ornithology., Competing Interests: No authors have competing interests.

Climate change has caused a clear and univocal trend towards advancement in spring phenology. Changes in autumn phenology are much more diverse, with advancement, delays, and 'no change' all occurring frequently. For migratory birds, patterns in autumn migration phenology trends have been identified based on ecological and life-history traits. Explaining interspecific variation has nevertheless been challenging, and the underlying mechanisms have remained elusive. Radar studies on non-species-specific autumn migration intensity have repeatedly suggested that there are strong links with weather. In long-term species-specific studies, the variance in autumn migration phenology explained by weather has, nevertheless, been rather low, or a relationship was even lacking entirely. We performed a spatially explicit time window analysis of weather effects on mean autumn passage of four trans-Saharan and six intra-European passerines to gain insights into this apparent contradiction. We analysed data from standardized daily captures at the Heligoland island constant-effort site (Germany), in combination with gridded daily temperature, precipitation and wind data over a 55-year period (1960-2014), across northern Europe. Weather variables at the breeding and stopover grounds explained up to 80% of the species-specific interannual variability in autumn passage. Overall, wind conditions were most important. For intra-European migrants, wind was even twice as important as either temperature or precipitation, and the pattern also held in terms of relative contributions of each climate variable to the temporal trends in autumn phenology. For the trans-Saharan migrants, however, the pattern of relative trend contributions was completely reversed. Temperature and precipitation had strong trend contributions, while wind conditions had only a minor impact because they did not show any strong temporal trends. As such, understanding species-specific effects of climate on autumn phenology not only provides unique insights into each species' ecology but also how these effects shape the observed interspecific heterogeneity in autumn phenological trends., (© 2019 John Wiley & Sons Ltd.)

Low-level wind shear, i.e., sudden changes in wind speed and/or wind direction up to altitudes of 1600 ft (500 m) above-ground is a hazardous meteorological phenomenon in aviation. It may radically change the aerodynamic circumstances of the flight, particularly during landing and take-off and consequently, it may threaten human lives and the health of passengers, people at the airport and its surrounding areas. The Bratislava Airport, the site of this case study, is one of the few airports worldwide and the first in Central Europe that is equipped with a Doppler lidar system, a perspective remote sensing tool for detecting low-level wind shear. The main objective of this paper was to assess the weather events collected over a period of one year with the occurrences of low-level wind shear situations, such as vertical discontinuities in the wind field, frontal passages and gust fronts to increase the level of flight safety and protect human lives and health. The lidar data were processed by a computer algorithm with the main focus on potential wind shear alerts and microburst alerts, guided by the recommendations of the International Civil Aviation Organisation. In parallel, the selected weather events were analyzed by the nearby located meteorological radar to utilize the strengths of both approaches. Additionally, an evaluation of the lidar capability to scan dynamics of aerosol content above the airport is presented.

The Operational Program on the Exchange of Weather Radar Information (OPERA) has co-ordinated radar co-operation among national weather services in Europe for more than 20 years. It has introduced its own, manufacturer-independent data model, runs its own data center, and produces Pan-European radar composites. The applications using this data vary from data assimilation to flood warnings and the monitoring of animal migration. It has used several approaches to provide a homogeneous combination of disparate raw data and to indicate the reliability of its products. In particular, if a pixel shows no precipitation, it is important to know if that pixel is dry or if the measurement was missing. [ABSTRACT FROM AUTHOR]

High Frequency Radar (HFR) is the unique land-based remote sensing technology that allows the mapping of ocean surface currents over wide areas with high spatial and temporal resolution. HFR products are applied in many sectors such as research in coastal oceanography and marine environment, safety, coastal management, fishery, navigation and renewable energy. Furthermore, it is expected that HFR data will be systematically ingested in Data Assimilation processes necessary for predictive model adjustment.HFR technology is rapidly expanding in Europe (at a rate of 7 new systems per year since 2016), with over 62 HFR sites currently operating and a number in the planning stage.The coordinated development of coastal HFR technology and its products is essential to ensure that the potential of HFRs is fully exploited in the development of the European operational oceanography. The EuroGOOS HFR Task Team is leading, with the support of the European Marine Observation and Data Network (EMODnet), many ongoing initiatives aiming at promoting the HFR technology in Europe. These efforts brought to the the inclusion of HFR data into the major European platforms for marine data distribution, which are: Copernicus Marine Environment Monitoring Service In Situ Thematyic Assembly Center (CMEMS-INSTAC), SeaDataCloud (SDC) and EMODnet Physics. Building on these achievements, the European HFR Node was established as the infrastructure to drive the needed steps to reach the added-value of a coordinated network like: central archiving, homogenized protocols for data distribution, development of standards for quality assurance, control and data structures. The European platforms for marine data distribution operate through a decentralized architecture based on National Oceanographic Data Centers (NODC), Production Units (PUs) organized by region for the global ocean and the six European seas and a Global Distribution Unit (DU). The European HFR Node acts as the focal point for the European HFR data providers toward this decentralized structure, since it implements the HFR data stream from the data providers to the distribution platforms.The European HFR Node is founded on a simple and very effective rule: if the data provider can set up the data flow according to the defined standards, the node only checks and includes the new catalogue and data stream. If the data centre cannot setup the data flow, the HFR Node harvests the raw data from the provider, harmonizes, quality-controls and formats these data and makes them available.The strength and flexibility of this solution reside in the architecture of the European HFR node, that is based on a centralized database, fed both by the operators via a webform and by the software routines running on the node, containing updated metadata of the HFR networks and the needed information for processing/archiving the data. A set of shared software tools uses all those information for processing native HFR data for QC and converting them to the standard format for distribution.The European HFR Node is pre-operational since November 2018 and will be fully operational in April 2019 for CMEMS-INSTAC, EMODnet Physics and SDN/SDC data delivery. [ABSTRACT FROM AUTHOR]

Land subsidence associated with overexploitation of aquifers is a hazard that commonly affects large areas worldwide. The Lorca area, located in southeast Spain, has undergone one of the highest subsidence rates in Europe as a direct consequence of long-term aquifer exploitation. Previous studies carried out on the region assumed that the ground deformation retrieved from satellite radar interferometry corresponds only to vertical displacement. Here we report, for the first time, the two- and three-dimensional displacement field over the study area using synthetic aperture radar (SAR) data from Sentinel-1A images and Global Navigation Satellite System (GNSS) observations. By modeling this displacement, we provide new insights on the spatial and temporal evolution of the subsidence processes and on the main governing mechanisms. Additionally, we also demonstrate the importance of knowing both the vertical and horizontal components of the displacement to properly characterize similar hazards. Based on these results, we propose some general guidelines for the sustainable management and monitoring of land subsidence related to anthropogenic activities.

The article discusses on the applications of wireless communication networks in the efforts to have accurate monitoring of the environment, which include weather forecasting and pollution regulation. Researchers emphasizes that cellular networks are like global positioning system that provide built-in monitoring facilities and promotes wide distribution and real time operation. They comment that the use of radar in meteorological monitoring of rainfall is less accurate at surface levels. The suggested the use of digital fixed radio system that have established as the premier cellular backhaul technology in Europe and Asia.

Reports that the United States National Geospatial Intelligence Agency (NGA) has nearly completed the processing of data derived from the Shuttle Radar Topography Mission for Europe and Asia. Collaboration between NGA, the U.S. National Aeronautics and Space Administration, German and Italian space agencies; Web site providing elevation data for all of the Western hemisphere and most of Eurasia.