Gravity waves are a significant driver of middle atmosphere dynamics with various excitation sources, e.g. the jet stream, convection zones, flow over orography and natural hazards such as tsunamis. OH-airglow measurements allow continuous night-time observations of gravity waves and various other wave types including singular events like bores and wall events at an altitude of about 86 km.Their respective signals are subject to the measurement system “Observations of Airglow with Spectrometer and Imager Systems” (OASIS). Imager systems allow the derivation of wave parameters such as the horizontal wavelength and the propagation direction. Data from spectrometers complement this information with wave amplitudes derived in temperature and absolute OH radiance.Since November 2022, the measurement system OASIS started routine observations at the Very Large Telescope (VLT) in the Atacama Desert at Cerro Paranal, Chile (24.6°S, 70.4°W) in cooperation with the European Southern Observatory (ESO). It is composed of two Fast Airglow Imagers (FAIM) and one Ground-based infrared P-branch Spectrometer (GRIPS) with high temporal resolution (1 image every 1/2 seconds, 1 spectrum every 15 seconds). Currently, over three years of data with nearly 100% night-time data coverage have been acquired. One of the goals of the observation site beside the general investigation of atmospheric dynamics is the investigation of tsunami-induced signals in OH airglow.Monitoring the OH airglow provides a unique opportunity to make continuous night-time observations of the middle atmosphere with high temporal and spatial resolution. However, the OH airglow causes noise in ground-based astronomical observations in the short-wave infrared like performed with the VLT due to its emissions in this spectral range. The project AirMon-VLT (“Airglow Monitor at the VLT”) brings together the interests of atmospheric scientists to understand middle atmosphere dynamics even better and astronomers who want to precisely know about the OH airglow variability and radiance. With this detailed knowledge an improved scheduling of deep sky observations for example at times with low OH airglow variability and radiance could be achieved. Also, precise and highly temporally resolved information about the change of OH airglow radiance can help to improve the correction of astronomical spectra.Within AirMon-VLT, the short and medium-term variability of OH airglow is investigated with statistical methods answering questions like which changes in airglow radiance could typically be expected within minutes/hours/days/etc., e.g. due to infrasound, gravity waves, tides, planetary waves, and by singular events like bore or wall events. With methods from the field of artificial intelligence predictions of the airglow variability will be made into the near and medium future (nowcasting and forecasting) to allow for a better scheduling of the astronomical targets. Also, additional data like ERA5 reanalysis data will be investigated for a more comprehensive understanding of causes of the variability from lower atmospheric layers.We present the project AirMon-VLT and the measurement system OASIS. We show first results of statistical evaluations about typical changes of airglow radiances related to various wave phenomena, including singular events like a potential wall event with an exceptional high radiance change of 60% within only one hour.

For many decades, hydroxyl (OH) airglow has been used to study atmospheric dynamics on different scales from infrasound and gravity waves to tides and planetary waves. These measurements refer to the upper mesosphere/lower thermosphere; they are mostly ground-based and only performed at night. In recent years, equivalent space-based measurements, i.e. nadir and off-nadir measurements, have also been carried out by instruments such as Suomi/VIIRS (Visible Infrared Imaging Radiometer Suite) and AWE (Atmospheric Wave Experiment).Unlike ground-based measurements, satellite-based instruments can provide global or nearly global information depending on the orbit. However, nadir and off-nadir space-based measurements are subject to additional unwanted background signals. The main sources of this background radiation are moonlight reflected by clouds and the Earth's surface, as well as emissions from artificial lights on the ground. Whether the background radiation omits the analysis of space-based OH-airglow data with respect to atmospheric waves depends on the strength of the background signal and of its spatial and temporal variations compared to the dynamically-induced variations of the OH airglow.Suomi/VIIRS operates in a spectral range that is not ideal for OH-airglow observations and does not utilise a dedicated background channel; OH-airglow measurements are only possible on moonless nights against a dark background. This limitation could be reduced by measuring the strongest OH-airglow emissions in the infrared, and by using a background channel. SOVA-S is one such concept. It was selected as one of four projects for the consolidation phase in the second ESA SCOUT cycle in 2025, focusing on OH(3-1) Q-branch measurements.The measurement concept of SOVA-S is briefly introduced, along with the differences to AWE — an OH airglow mission in the infrared with an onboard background channel on the ISS. The conditions, under which atmospheric wave analyses should be possible with SOVA-S with regard to cloud cover, moon phase and surface albedo, are outlined; the underlying analyses were performed using the radiative transfer model SCIATRAN. Potential applications of these data in the context of applied research (e.g. the influence of middle atmospheric dynamics on the GNSS signal integrity) are presented.

BACKGROUND:Children are vulnerable to heat, yet evidence on heat-related pediatric emergency department (ED) use in Germany remains limited. We quantified the acute short-term effects of extreme heat exposure on ED visits among children aged 0-18 years in Baden-Württemberg, Germany. METHODOLOGY:We assessed short-term effects of extreme heat on ED visits among children aged 0-18 years, including perinatal conditions in infants born at or after 22 weeks´ gestation, in Baden-Württemberg, Germany using 2.83 million records from (2014-2022). A time-stratified quasi-Poisson design with distributed lag non-linear model (lag 0-5 days) was applied, adjusting for air quality, spatiotemporal factors, and COVID-19 hospitalizations. RESULTS:Higher temperatures increased ED visits risk, strongest within 0-2 days. Cumulative relative risks increased by 4.2% (95% CI 3.7-4.8), 7.1% (6.1-8.1), and 9.6% (8.2-11.1) at the 95th, 99th, and 99.9th temperature percentiles, respectively. Heat-sensitive diagnoses included heat-related illnesses (+63%, 51-76), perinatal conditions (+57%, 26-92), and otitis media and externa (+25%, 16-33). Children < 5 years had higher ED visit rates share on hot days (RR 1.036, 1.02-1.05). CONCLUSION:Heat exposure increases pediatric ED use, highlighting the need of child-specific thresholds and targeted preparedness strategies. IMPACT:Extreme heat increases pediatric emergency visits, especially among infants and young children. By combining high resolution meteorological data with a large pediatric dataset and advanced time stratified modeling, the study provides detailed evidence on short-term effects of heat and identifies specific heat sensitive diagnoses. The study highlights rapid, lagged effects of heat and suggests pediatric specific temperature thresholds that may better capture risk than current heat warning thresholds. The findings support improving preparedness in pediatric emergency care and inform adaptations to heat warning-systems to better cater for child populations.

Since June 2019, a scanning airglow camera is operated operationally every night at DLR Oberpfaffenhofen (48.09 degrees N, 11.28 degrees E), Germany. It provides nearly all-sky images (diameter 500 km) of the OH* airglow layer (height ca. 85-87 km) with an average spatial resolution of ca. 150 m and a temporal resolution of ca. 2 min.We analyse about three years (941 nights between October 2020 and September 2023) of OH* airglow all-sky images for spatially confined wave structures with horizontal wavelengths of ca. 20 km and less. Such structures are often referred to as ripples and are considered to be instability structures. However, Li et al. (2017) showed that they could also be secondary waves. While ripples move with the background wind, secondary waves do not.To identify small-scale and spatially confined structures, we adapt and train YOLOv7 (You Only Look Once, version 7), a machine learning approach, to determine their position and extent on the sky as well as their horizontal wavelength. Those wavelengths are compared to two-dimensional FFT (Fast Fourier Transform) results. We analyse the seasonal variations in the orientation of the wave fronts, the direction of advection and the horizontal wavelengths of these structures and deduce that instability signatures are observed especially in summer.Finally, we introduce a concept for "operating-on-demand" in order to derive energy dissipation rates from our measurements.

Temperature profiles retrieved from the 355-nm Rayleigh channel of the big Raman lidar at the Schneefernerhaus high-altitude station (UFS, 2675 m a.s.l.), calibrated with mesopause OH airglow measurements at UFS, are compared with corresponding profiles from the Microwave Limb Sounder (MLS) for nearby passa-ges. Above 40 km the MLS temperatures exhibit a low bias with respect to the lidar.

This study investigates the temporal variability of tropospheric NO2 vertical column density over Milan in Italy and its surrounding area using daily satellite observations from Aura/OMI over the period of 2004-2023. The analysis reveals a significant long-term decrease of 55 % in NO2 pollution which is consistent with previous studies. Using spectral analysis techniques such as wavelet and harmonic analysis, we identified distinct oscillation patterns such as an annual cycle linked to seasonal heating and NO2 lifetime variations, and shorter-term variabilities of 6.5-7.5 days (I7) as well as two to five days (I3). The I7 pattern, attributed to weekly traffic variations, shows consistent presence throughout the study period, while I3 exhibits notable temporal variations. The I3/I7 ratio demonstrates significant shifts corresponding to major economic events, including the 2008 global economic crisis and the COVID-19 pandemic. Notably, the increased adoption of remote work during the pandemic (2.5 %-12 % between 2019 and 2021) disrupted traditional weekly commuting patterns, reflected in enhanced I3 dominance. This study establishes a clear connection between economic activities, commuting behavior, and NO2 variability patterns, demonstrating how the shift to remote work, leaves distinct signatures in atmospheric NO2 variability.

Gravity waves transport momentum and energy vertically and horizontally and play a key role for the circulation in the upper mesosphere and lower thermosphere (UMLT). They can experience convective or dynamic instabilities or undergo nonlinear interactions with the background flow. The UMLT is of particular importance, as gravity waves frequently reach their breaking levels in this region, often referred to as the turbopause.This altitude range is observed using two FAIM cameras measuring the OH-airglow emission centered at approximately 86 km altitude, with a full width at half maximum of about 7–8 km, from different locations. By applying a newly developed tomographic reconstruction technique to coordinated dual-camera OH-airglow observations of the same air volume, the three-dimensional structure of gravity waves in the UMLT can be recovered. The resulting volumetric data provide detailed information about horizontal and vertical gravity-wave features, representing a middle-atmosphere sounding technique complementary to established methods such as lidar or radar observations. To characterize these waves, vertical wavelengths are extracted in a dedicated post-processing step by applying a two-dimensional FFT to selected altitude layers of the tomographically reconstructed volume. This approach provides access to vertical phase progression and vertical wavelength information that is fundamentally unattainable with a single OH airglow imager. By analyzing the phase differences of the wave signals in the FFT spectra between different altitude layers, the vertical propagation angle can be derived. In combination with the horizontal wavelength, this enables the determination of the vertical wavelength and thus a full three-dimensional gravity-wave characterization.First results from this dual-FAIM tomographic approach are presented, demonstrating both the feasibility and the performance of the method. The analysis is based on coordinated OH-airglow observations from FAIM installations at Oberpfaffenhofen (lon = 11.28, lat = 48.09) and Otlica (lon = 13.91, lat = 45.94) over a one-year period. These data are used to assess retrieval quality, identify sensitivity limits for vertical wavelength derivations, and demonstrate the enhanced scientific value of three-dimensional gravity-wave characterization for multi-instrument analyses of middle-atmosphere dynamics.Within the project GIGAWATT, a collaboration of the German Aerospace Center, the University of Augsburg and the University of Bern, we are currently advancing this work by incorporating new measurements and combining complementary observational techniques, including radiometric temperature and wind observations in the stratosphere and lower mesosphere and multi-static OH airglow tomography, to establish a high-resolution gravity-wave observatory for the Alpine region. This work is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under the project number 540878795.

In efforts to mitigate the effects of global climate change several prominent policies and guidelines which emphasize the importance of sustainable growth have been introduced in recent years. Examples include the 2019 European Green Deal, and the subsequent Clean Industrial Deal in 2025. A key aspect of these goals is the reduction of air pollutant emissions, particularly from fossil fuel combustion, without sacrificing economic growth. The Green Deal commits to an EU wide emission reduction of at least 55% by 2030, as compared to 1990 levels. Remote sensing offers many advantages for tracking progress towards reduction of pollutant emissions. In particular, the global coverage allows for analysis of regions which do not have sufficient ground-based measurement networks. This study presents a method of using spectral analysis with tropospheric NO2 column density and the gross domestic product (GDP) to track and compare progress of the German federal states towards decoupling emissions from economic growth. Most studies evaluating economic decoupling focus on CO2, or CO2 equivalences. There is a current lack of studies which investigate other key combustion products. This study focuses on NO2 as a proxy for emissions related to economic activity. NO2 originates primarily from anthropogenic combustion sources, andhas a short tropospheric lifetime, making it suitable to represent localized fossil fuel emissions. Measurements of NO2 used in this study are obtained from the Ozone Monitoring Instrument (OMI) launched aboard the NASA Aura satellite in 2004. The application of spectral analysis techniques, such as the wavelet analysis, gives additional insight into temporal variability of NO2, to better observe the path of decoupling for each region. Decoupling between GDP and NO2 variability is observed for all regions of Germany in the period between the two most recent global economic recessions (the 2008 financial crisis, and the Covid-19 pandemic). Similar decreasing trends are observed for both the yearly average tropospheric column density and the calculated yearly variability. The variability obtained from the wavelet analysis shows greater sensitivity to changes in NO2 emissions than the absolute tropospheric column density. Further regional differences such as the main economic sectors and types of emission regulations in place are discussed to contextualize the differences present in decoupling processes between the federal states. Overall, NO2 variability is found to be a sensitive and effective indicator for tracking and comparing decoupling progress across different administrative regions.

The Low Frequency Array (LOFAR) is one of the most advanced radio telescopes in the world. When radio waves from a distant astronomical source traverse the ionosphere, structures in this plasma affect the signal. Results are presented from a statistical study using 2,810 hours of observations of Cassiopeia A from a LOFAR station located in the Netherlands (station CS032, located at 52.9o N; 6.9o E) between 28th June 2014 and 27th November 2016. Ionospheric structures were identified in 469 (~17 %) of these observations. A comparison with proxies for geomagnetic activity (the Kp index) and solar activity (the F10.7 cm solar radio flux) showed that geomagnetic or solar effects were not the primary driver of these ionospheric structures. Ionospheric structures were more common in summer and between ~21 LT – 02 LT. These patterns in season and local time showed similarities to the occurrence of lightning strikes. When ionospheric structures were present, the mean number of lightning strikes in a spatial region close to the LOFAR observations (51.9o – 56.5o N; 3.9o – 9.9o E) two hours prior to the LOFAR observations was (70 ± 25) per hour. This was substantially larger than the mean value of (19 ± 5) per hour when the ionospheric structures were absent. This suggests that quasi-upward propagating Atmospheric Gravity Waves (AGWs) launched by thunderstorm activity could be one of the sources of the ionospheric structures. Collectively, these observations show that LOFAR can be used to infer ionospheric signatures of vertical coupling processes in the mid-latitude atmosphere. Such observations have the potential to be used to develop or validate existing Global Circulation Models (GCMs) or new models of vertical coupling within the terrestrial atmosphere.

Information about the energy density of gravity waves (GWs) is crucial for improving atmosphere models. So far, most space-based studies report the potential energy, Epot, of GWs, as temperature measurements from satellites are more common. We use Aeolus wind data to derive the kinetic energy density, Ekin, of GWs above the northern Atlantic and Europe. Assuming perfect instrument performance, this would be a lower limit for the kinetic energy density, as Aeolus only measures the horizontal line-of-sight wind. Aeolus, the European Space Agency's (ESA's) fourth Earth Explorer Mission, was the first Doppler wind lidar in space and measured vertical profiles of the horizontal line-of-sight wind from the ground to an altitude of ∼ 20–30 km between 2018 and 2023. With a vertical resolution of 0.25–2 km, Aeolus measurements are in principle well suited for the analysis of GWs. However, the data quality is a challenge for such analyses, as the error in the data is in the range of typical GW amplitudes in the troposphere and stratosphere. In this study, we derive daily resolved time series of Ekin before, during, and after two streamer events above the northern Atlantic and Europe. Streamers are large-scale tongue-like structures of meridionally deflected air masses, which are caused by enhanced planetary wave activity. They are linked to vertical shear of horizontal wind and a pressure system, two possible GW generation mechanisms. We find that there is a temporal coincidence between the enhanced daily averaged Ekin and occurrence of the streamer events, which we identified in total column ozone measurements. The derivation of GW signals based on Aeolus data is possible, however: we collected about 100 profiles to statistically reduce the uncertainty in the daily averaged Ekin. Compared to non-satellite measurements, those daily averaged values are at the upper border.

COVID-19 had a devastating impact on humanity. We investigated how residential air pollution (ozone (O3), nitrogen dioxide (NO2), fine particulate matter (PM2.5)) and meteorological factors (temperature (Temp), precipitation (Prec)) are associated with COVID-19 incidence in Baden-Württemberg (BW), Germany. We utilized data from the Copernicus Atmosphere Monitoring Service and the Copernicus Climate Change Service to model environmental exposure from 2020 to 2022 in postal code areas in BW. Health insurance data on SARS-CoV-2 infections were provided from the health insurance AOK BW on a quarterly level covering approximately 12 million person-years. We examined the spatiotemporal variability with a generalized additive model including various stressors, demographic factors, and area-wide data, offering a comprehensive analysis of the environmental stressor- COVI-10 incidence associations. In 2022, during the prevalence of the Omicron variant, the number of COVID-19 cases tripled compared to 2020. During the pre-Omicron period, COVID-19 incidence showed a positive association with PM2.5 (relative risk [RR] 2.41; 95% confidence interval [CI] (2.31, 2.52)), a negative association with Temp (RR 0.39 (0.32, 0.48)), and no clear or slight associations with O3, Prec, and NO2. During the Omicron period, there were either no clear or slight negative associations with Temp (RR 0.92 (0.74, 1.30)), PM2·5 (RR 0.70 (0.64, 0.79)), NO2, and Prec and a negative association with O3 (RR 0.46 (0.40, 0.53)). The analysis found clear links between environmental stressors and COVID-19 incidence, which strongly differed between pre-Omicron and Omicron periods. Consideration of environmental stressor concentration could be relevant in the management of the pandemic.

In this study we examine the performance of the 354.8 nm Rayleigh temperature channel of the Raman lidar at the Schneefernerhaus high-altitude research station (UFS) in the Bavarian Alps (at 2675 m a.s.l.). The temperature reference value of the retrieval is adjusted to match the temperature determined from the OH* airglow around 86 km by the GRIPS instruments at UFS. In this way the quality of the 1 h measurements of the lidar is improved above 70 km. Comparisons were made between the UFS lidar, the MLS (Microwave Limb Sounder) satellite-borne instrument and the 354.8 nm temperature channel of Hohenpei ss enberg (MOHp) differential-absorption ozone lidar. Between 35 and 70 km we see a positive offset of the UFS temperatures with respect to the MLS values of up to about 9 K. This behaviour just slightly exceeds the expectations from earlier work. Despite a horizontal distance of just 40 km between UFS and MOHp acceptable agreement below 70 km was found in several cases. However, in general, the MOHp temperatures were slightly lower than those above UFS. We discuss potential technical issues and suggest solutions for upgrading the UFS lidar system. A significant enhancement of the laser repetition rate is recommended.

The dynamics in the atmosphere, especially the upper mesosphere and mesopause are significantly driven by atmospheric gravity waves. OH airglow offers an unique possibility to observe atmospheric dynamics in this altitude region with a high spatio-temporal resolution simultaneously using imager and spectrometer systems. Especially, characteristics of gravity waves as well as features like wave breaking and wave-wave interaction can be observed. Spectroscopic observations allow observing rotational temperature changes. Thus, both instrument types complement each other very well. Since November 2022 two airglow imagers (FAIM) and one airglow spectrometer (GRIPS) with high temporal resolution (1 image every 2 seconds, 1 spectrum every 15 seconds) started routine observations during each night in cooperation with and at ESO’s Very Large Telescope (VLT) in the Atacama Desert at Cerro Paranal, Chile (24.6°S, 70.4°W). During the night from 31st July to 1st August 2023 we observed an exceptional bright night that is much brighter than any other we observed so far: a single wave front propagates from West to East with an observed phase speed of about 60m/s. After the passing of the wave front the OH intensity decreases by around 50% within only one hour. Pronounced wave activity of small-scale waves is observed especially before the passing of the event. Similar events in literature are often stated as “wall events”, but seem to occur very rarely in the extent observed. We present and interpret the wall event and discuss the observed phenomenon and its causes using data from multiple instruments and data sources.

The Earth's mesopause region between about 75 and 105 km is characterised by chemiluminescent emission from various lines of different molecules and atoms. This emission was and is important for the study of the chemistry and dynamics in this altitude region at nighttime. However, our understanding is still very limited with respect to molecular emissions with low intensities and high line densities that are challenging to resolve. Based on 10 years of data from the astronomical X-shooter echelle spectrograph at Cerro Paranal in Chile, we have characterised in detail this nightglow (pseudo-)continuum in the wavelength range from 300 to 1800 nm. We studied the spectral features, derived continuum components with similar variability, calculated climatologies, studied the response to solar activity, and even estimated the effective emission heights. The results indicate that the nightglow continuum at Cerro Paranal essentially consists of only two components, which exhibit very different properties. The main structures of these components peak at 595 and 1510 nm. While the former was previously identified as the main peak of the FeO “orange arc” bands, the latter is a new discovery. Laboratory data and theory indicate that this feature and other structures between about 800 and at least 1800 nm are caused by emission from the low-lying A′′ and A′ states of HO2. In order to test this assumption, we performed runs with the Whole Atmosphere Community Climate Model (WACCM) with modified chemistry and found that the total intensity, layer profile, and variability indeed support this interpretation, where the excited HO2 radicals are mostly produced from the termolecular recombination of H and O2. The WACCM results for the continuum component that dominates at visual wavelengths show good agreement for FeO from the reaction of Fe and O3. However, the simulated total emission appears to be too low, which would require additional mechanisms where the variability is dominated by O3. A possible (but nevertheless insufficient) process could be the production of excited OFeOH by the reaction of FeOH and O3.

Abstract When analyzing health data in relation to environmental stressors, it is crucial to identify which variables to include in the statistical model to exclude dependencies among the variables. Four meteorological parameters: temperature, ultraviolet radiation, precipitation, and vapor pressure and four outdoor air pollution parameters: ozone ( $$\text{O}_3$$ O 3 ), nitrogen dioxide ( $$\text{NO}_2$$ NO 2 ), particulate matter ( $$PM_{2.5}$$ P M 2.5 , $$PM_{10}$$ P M 10 ) were studied on a daily basis for Baden-Württemberg (Germany). This federal state covers urban and rural compartments including mountainous and river areas. A temporal and spatial analysis of the internal relationships was performed among the variables using (a) cross-correlations, both on the grand ensemble of data as well as within subsets, and (b) the Local Indications of Spatial Association (LISA) method. Meteorological and air pollution variables were strongly correlated within and among themselves in time and space. We found a strong interaction between nitrogen dioxide and ozone, with correlation coefficients varying over time. The coefficients ranged from negative correlations in January (−0.84), April (−0.47), and October (−0.54) to a positive correlation in July (0.45). The cross-correlation plot showed a noticeable change in the correlation direction for $$\text{O}_3$$ O 3 and $$\text{NO}_2$$ NO 2 . Spatially, $$\text{NO}_2$$ NO 2 , $$PM_{2.5}$$ P M 2.5 , and $$PM_{10}$$ P M 10 concentrations were significantly higher in urban than rural regions. For $$\text{O}_3$$ O 3 , this effect was reversed. A LISA analysis confirmed distinct hot and cold spots of environmental stressors. This work examined and quantified the spatio-temporal relationship between air pollution and meteorological conditions and recommended which variables to prioritize for future health impact analyses. The results found are in line with the underlying physico-chemical atmospheric processes. It also identified postal code areas with dominant environmental stressors for further studies.

The ionosphere as a part of Earth’s atmosphere supports a wide range of oscillations, of which acoustic–gravity waves (AGWs) form an important part. AGWs distribute energy and momentum from the source region over large distances. A significant portion of AGWs originates in the lower atmosphere and propagates through the atmosphere up to the ionospheric heights where, due to the coupling between neutral and ionized particles, it could be detected as wavelike disturbances of the plasma. Primarily, the ionospheric behavior is driven by solar and geomagnetic activity, while the influence from neutral and below-laying regions of the atmosphere most of the time forms a substantially smaller part of the observed variability. However, it could significantly alter ionospheric behavior. Our study is limited to a time span of rather low solar and geomagnetic activity in order to highlight neutral atmosphere influence. In this study, we focus on two tropospheric situations above Europe that may lead to AGW generation, which propagate up to the F-layer where they potentially induce variability that we observe within ionospheric plasma parameters.

&lt;p&gt;The line emission from the various roto-vibrational bands of the OH radical is an important tracer of the chemistry and dynamics in the Earth&#039;s nocturnal mesopause region between about 80 and 100 km. As most studies have focused either on a few bright lines or integrated emission from relatively wide wavelength windows, there is still a lack of knowledge with respect to the variability of faint lines from high rotational levels as well as the change of the variability patterns depending on the line parameters, which influence the effective emission height. Thanks to a large data set of about 90,000 near-infrared X-shooter spectra taken at Cerro Paranal in Chile within a time interval of 10 years, we have been able to derive line-specific climatologies of intensity, solar cycle effect, and residual variability for local time and day of year based on a set of 298 OH lines. Our analysis of the derived climatologies involves different decomposition techniques, the study of the variance depending on the time scale of the perturbation, and the calculation of correlations for the line dependence of different properties. The considered effective line emission heights originate from the investigation of the propagation of a strong quasi-2-day wave in 2017 using the X-shooter and space-based SABER data. Our results for the entire X-shooter data set reveal the importance of the mixing of thermalised and non-thermalised rotational populations for the amplitude of a perturbation as well as a shift of the climatological variability patterns with local time depending on the emission height. The latter implies a strong influence of the migrating diurnal tide and causes significant line-dependent differences in the effective solar cycle effect, which mainly depends on the solar forcing in the austral winter.&lt;/p&gt;

In this poster contribution, we present a scheduling system for automated remote operation of instruments at high-altitude research facilities and similar remote sites. Via web-based interfaces, the system allows instrument owners as well as authorized third-party scientists to schedule and execute measurements and observations.The system has been developed as a thesis project in the context of the AlpEnDAC-II ("Alpine Environmental Data Analysis Centre", www.alpendac.eu) collaboration (funded by the Bavarian State Ministry of the Environment and Consumer Protection). Consequently, the scheduler and interfaces have been integrated with the AlpEnDAC Operating-on-Demand functionalities. A first use case for the framework has been the operation of an airglow imager (FAIM) in Oberpfaffenhofen (DE).We describe the design and implementation of our system for scheduling and execution of multi-user observations on instruments, including scheduling-data transfers and data retrieval. Our core implementation uses an optimization-based scheduler (Google's OR-Tools) to ensure maximum instrument use and to minimize idle times. Results show that the scheduler is reliable, fast, and is consistently able to provide optimal observation plans. The extensibility of the system is guaranteed by the usage of modern software in the core of the system, including well-defined and specified communication through REST APIs. Thus, it can easily be adapted to other settings and instruments, which is also facilitated by a modern deployment strategy using Docker and Kubernetes.