Observations of Elevated Formaldehyde Over a Forest Canopy suggest Missing Sources From Rapid Oxidation of Arboreal Hydrocarbons

To better understand the processing of biogenic VOCs (BVOCs) in the pine forests of the US Sierra Nevada, we measured HCHO at Blodgett Research Station using Quantum Cascade Laser Spectroscopy (QCLS) during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) of late summer 2007. Four days of the experiment exhibited particularly copious HCHO, with midday peaks between 15–20 ppbv, while the other days developed delayed maxima between 8–14 ppbv in the early evening. From the expansive photochemical data set, we attempt to explain the observed HCHO concentrations by quantifying the various known photochemical production and loss terms in its chemical budget. Overall, known chemistry predicts a factor of 3–5 times less HCHO than observed. By examining diurnal patterns of the various budget terms we conclude that, during the high HCHO period, local, highly reactive oxidation chemistry produces an abundance of formaldehyde at the site. The results support the hypothesis of previous work at Blodgett Forest suggesting that large quantities of oxidation products, observed directly above the ponderosa pine canopy, are evidence of profuse emissions of very reactive volatile organic compounds (VR-VOCs) from the forest. However, on the majority of days, under generally cooler and more moist conditions, lower levels of HCHO develop primarily influenced by the influx of precursors transported into the region along with the Sacramento plume

Remote Sensing Monitoring of Land Surface Temperature (LST)

This book is a collection of recent developments, methodologies, calibration and validation techniques, and applications of thermal remote sensing data and derived products from UAV-based, aerial, and satellite remote sensing. A set of 15 papers written by a total of 70 authors was selected for this book. The published papers cover a wide range of topics, which can be classified in five groups: algorithms, calibration and validation techniques, improvements in long-term consistency in satellite LST, downscaling of LST, and LST applications and land surface emissivity research

Nighttime Lights as a Proxy for Economic Performance of Regions

Studying and managing regional economic development in the current globalization era demands prompt, reliable, and comparable estimates for a region’s economic performance. Night-time lights (NTL) emitted from residential areas, entertainment places, industrial facilities, etc., and captured by satellites have become an increasingly recognized proxy for on-ground human activities. Compared to traditional indicators supplied by statistical offices, NTLs may have several advantages. First, NTL data are available all over the world, providing researchers and official bodies with the opportunity to obtain estimates even for regions with extremely poor reporting practices. Second, in contrast to non-standardized traditional reporting procedures, the unified NTL data remove the problem of inter-regional comparability. Finally, NTL data are currently globally available on a daily basis, which makes it possible to obtain these estimates promptly. In this book, we provide the reader with the contributions demonstrating the potential and efficiency of using NTL data as a proxy for the performance of regions

Diurnal variability of atmospheric O-2, CO2, and their exchange ratio above a boreal forest in southern Finland

The exchange ratio (ER) between atmospheric O(2 )and CO2 is a useful tracer for better understanding the carbon budget on global and local scales. The variability of ER (in mol O(2 )per mol CO2) between terrestrial ecosystems is not well known, and there is no consensus on how to derive the ER signal of an ecosystem, as there are different approaches available, either based on concentration (ERatmos) or flux measurements (ERforest). In this study we measured atmospheric O-2 and CO2 concentrations at two heights (23 and 125 m) above the boreal forest in Hyytiala, Finland. Such measurements of O-2 are unique and enable us to potentially identify which forest carbon loss and production mechanisms dominate over various hours of the day. We found that the ERatmos signal at 23 m not only represents the diurnal cycle of the forest exchange but also includes other factors, including entrainment of air masses in the atmospheric boundary layer before midday, with different thermodynamic and atmospheric composition characteristics. To derive ERforest, we infer O(2 )fluxes using multiple theoretical and observation-based micro-meteorological formulations to determine the most suitable approach. Our resulting ERforest shows a distinct difference in behaviour between daytime (0.92 +/- 0.17 mol mol(-1)) and nighttime (1.03 +/- 0.05 mol mol(-1)). These insights demonstrate the diurnal variability of different ER signals above a boreal forest, and we also confirmed that the signals of ERatmos and ERforest cannot be used interchangeably. Therefore, we recommend measurements on multiple vertical levels to derive O-2 and CO2 fluxes for the ERforest signal instead of a single level time series of the concentrations for the ERatmos signal. We show that ERforest can be further split into specific signals for respiration (1.03 +/-; 0.05 mol mol-1) and photosynthesis (0.96 +/- 0.12 molmol(-1)). This estimation allows us to separate the net ecosystem exchange (NEE) into gross primary production (GPP) and total ecosystem respiration (TER), giving comparable results to the more commonly used eddy covariance approach. Our study shows the potential of using atmospheric O-2 as an alternative and complementary method to gain new insights into the different CO2 signals that contribute to the forest carbon budget.Peer reviewe

Precision Poultry Farming

This book presents the latest advances in applications of continuous, objective, and automated sensing technologies and computer tools for sustainable and efficient poultry production, and it offers solutions to the poultry industry to address challenges in terms of poultry management, the environment, nutrition, automation and robotics, health, welfare assessment, behavior monitoring, waste management, etc. The reader will find original research papers that address, on a global scale, the sustainability and efficiency of the poultry industry and explore the above-mentioned areas through applications of PPF solutions in poultry meat and egg productio

Préparation à l'utilisation des observations de l'imageur d'éclairs de Météosat troisième génération pour la prévision numérique à courte échéance

En guise d'analyse initiale, une intercomparaison d'observations d'éclairs au-dessus de la Corse issues du détecteur Lightning Imaging Sensor de la Station Spatiale Internationale (ISS-LIS), du réseau de Météorage de basse fréquence (LF) et du réseau Lightning Mapping Array (LMA) SAETTA révèle que des enregistrements coïncidents des trois systèmes de localisation des éclairs peuvent être identifiés. Les éclairs de grande extension et de longue durée sont plus susceptibles d'être simultanément détectés par ISS-LIS et Météorage que les éclairs de petite extension et de courte durée. En utilisant les informations fournies par SAETTA, on constate que l'efficacité de détection des éclairs de l'instrument spatial ISS-LIS se dégrade pour les éclairs détectés par Météorage qui ne s'étendent pas sur plus de 7 km d'altitude. Cette méthodologie d'intercomparaison est aussi appliquée pour analyser les enregistrements du capteur spatial ISS-LIS par rapport aux observations du réseau National Lightning Detection Network (NLDN) sur le sud-est des États-Unis. Dans l'ensemble, les caractéristiques des éclairs analysées dans les deux régions ne sont pas seulement similaires quand elles sont comparées aux enregistrements du détecteur spatial ISS-LIS, mais aussi lorsque l'on compare leurs statistiques telles que décrites indépendamment par Météorage et NLDN. Il est conclu que Météorage et NLDN détectent et localisent les éclairs de la même manière. Avec l'avènement du détecteur spatial géostationnaire (GEO) Geostationary Lightning Mapper (GLM), les observations coïncidentes de ce même détecteur GLM avec des observations du réseau terrestre NLDN sont analysées en détail pour construire un algorithme complexe générant des données synthétiques géostationnaires d'éclairs à partir des données du réseau NLDN. Ce générateur de données synthétiques d'éclairs utilise d'abord différentes caractéristiques des éclairs déduites des observations NLDN et GLM pour entraîner des modèles d'apprentissage automatique, et crée ensuite les différents pixels lumineux constituant chaque éclair synthétique à partir des caractéristiques de ce même éclair. Enfin, ce générateur est appliqué aux enregistrements du réseau français Météorage afin de simuler des observations synthétiques de l'imageur Lightning Imager (LI) de la mission Meteosat Troisième Génération (MTG) au-dessus de la France. Finalement, la densité d'étendue des éclairs (FED) est calculée à partir de ces données synthétiques MTG-LI. La FED sert ensuite de source de données pour un nouveau schéma d'assimilation de données d'éclairs (LDA) dans le modèle opérationnel français AROME-France. Ici, une restitution bayésienne à 1 dimension (1DBay) inverse la densité FED et fournit des profils d'humidité relative. La méthode 1DBay s'avère efficace pour supprimer la convection parasite et pour favoriser la convection dans les régions à FED positive. En dernier lieu, les profils d'humidité relative restitués sont assimilés à l'aide du système variationnel 3D (3DVar) du modèle AROME-France. Malgré les résultats prometteurs de la méthode 1DBay, l'analyse AROME-France contredit les profils d'humidité relative restitués dans la mesure où l'humidité est augmentée dans certaines régions où les profils d'humidité relative restitués suggèrent une réduction de l'humidité de l'ébauche.As an initial analysis, an intercomparison of lightning observations over Corsica from the Lightning Imaging Sensor on the International Space Station (ISS-LIS), the Low Frequency (LF) Meteorage network, and the SAETTA Lightning Mapping Array (LMA) reveals that coincident flashes of all three lightning locating systems can be identified. Large and long-duration flashes are more likely detected by both ISS-LIS and Meteorage than small and short-duration flashes. Using the information provided by SAETTA, it is found that the flash detection efficiency of ISS-LIS degrades for flashes detected by Meteorage that do not extend over 7 km of altitude. This intercomparison methodology is further applied to analyze records of ISS-LIS relative to National Lightning Detection Network (NLDN) observations over the southeastern USA. Overall, the flash characteristics analyzed in both French and US regions are not only similar from ISS-LIS records, but also when comparing their statistics as depicted by Meteorage and NLDN. It is concluded that Meteorage and NLDN detect and locate lightning similarly. With the advent of the Geostationary Lightning Mapper (GLM) concurrent geostationary (GEO) GLM and ground-based NLDN lightning observations are analyzed in detail to develop a complex algorithm to generate GEO lightning pseudo-observations from NLDN records. The so-called GEO lightning pseudo-observation generator first relates NLDN and GLM flash characteristics to train machine learning models, and secondly creates pseudo-GEO events from the simulated GEO flash characteristics. Finally, this generator is applied to simulate synthetic Meteosat Third Generation (MTG) Lightning Imager (LI) observations over France using Meteorage records as input. Eventually, Flash Extent Density (FED) is inferred from that pseudo MTG-LI data. Pseudo MTG-LI FED serves as data source for a new lightning data assimilation (LDA) scheme in the French operational model AROME-France. Here, a 1-dimensional Bayesian (1DBay) retrieval inverts the FED observations and provides relative humidity (RH) profiles. The 1DBay proves to suppress spurious convection and promote convection in regions with positive FED. As a last step, retrieved RH profiles are assimilated using the 3D variational (3DVar) system of AROME-France. Despite promising results of the 1DBay, the AROME-France analysis contradicts the retrieved RH profiles in that humidity is increased in some regions where the retrieved RH profiles suggest a reduction of the background humidity

Impact of chlorine ion chemistry on ozone loss in the middle atmosphere during very large solar proton events

Solar coronal mass ejections can accelerate charged particles, mostly protons, to high energies, causing solar proton events (SPEs). Such energetic particles can precipitate upon the Earth\u27s atmosphere, mostly in polar regions because of geomagnetic shielding. Here, SPE-induced chlorine activation due to ion chemistry can occur, and the activated chlorine depletes ozone in the polar middle atmosphere. We use the state-of-the-art 1D stacked-box Exoplanetary Terrestrial Ion Chemistry (ExoTIC) model of atmospheric ion and neutral composition to investigate such events in the Northern Hemisphere (NH). The Halloween SPE that occurred in late October 2003 is used as a test field for our study. This event has been extensively studied before using different 3D models and satellite observations. Our main purpose is to use such a large event that has been recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on the Environmental Satellite (ENVISAT) to evaluate the performance of the ion chemistry model. Sensitivity tests were carried out for different model settings with a focus on the chlorine species of HOCl and ClONO2 as well as O3 and reactive nitrogen, NOy. The model simulations were performed in the Northern Hemisphere at a high latitude of 67.5∘ N, inside the polar cap. Comparison of the simulated effects against MIPAS observations for the Halloween SPE revealed rather good temporal agreement, also in terms of altitude range for HOCl, O3 and NOy. For ClONO2, good agreement was found in terms of altitude range. The model showed ClONO2 enhancements after the peak of the event. The best model setting was the one with full ion chemistry where O(1D) was set to photo-chemical equilibrium. HOCl and ozone changes are very well reproduced by the model, especially for nighttime. HOCl was found to be the main active chlorine species under nighttime conditions, resulting in an increase of more than 0.2 ppbv. Further, ClONO2 enhancements of 0.2–0.3 ppbv have been observed during both daytime and nighttime. Model settings that compared best with MIPAS observations were applied to an extreme solar event that occurred in AD 775, presumably once in a 1000-year event. With the model applied to this scenario, an assessment can be made about what is to be expected at worst for the effects of a SPE on the middle atmosphere, concentrating on the effects of ion chemistry compared to crude parameterizations. Here, a systematic analysis comparing the impact of the Halloween SPE and the extreme event on the Earth\u27s middle atmosphere is presented. As seen from the model simulations, both events were able to perturb the polar stratosphere and mesosphere with a high production of NOy and HOx. Longer-lasting and stronger stratospheric ozone loss was seen for the extreme event. A qualitative difference between the two events and a long-lasting impact on HOCl and HCl for the extreme event were found. Chlorine ion chemistry contributed to stratospheric ozone losses of 2.4 % for daytime and 10 % for nighttime during the Halloween SPE, as seen with time-dependent ionization rates applied to the model. Furthermore, while comparing the Halloween SPE and the extreme scenario, with ionization rate profiles applied just for the event day, the inclusion of chlorine ion chemistry added ozone losses of 10 % and 20 % respectively

Turbulent exchange of carbon dioxide in a complex urban environment : results from Long-term Eddy Covariance measurements

Within this thesis, characteristics of the turbulent exchange within the urban boundary layer, as well as long-term trends and tendencies of the carbon dioxide flux (FC) and concentration (rhoC) are presented. Prevailing transport processes, the transfer and transport efficiencies of the turbulent exchange of momentum, heat, CO2 and H2O and the importance of coherent turbulent motions within the urban boundary layer are studied by applying the quadrant analysis technique. The behavior of FC and rhoC in the urban environment is investigated on daily, seasonal, and inter-annual scales as well as in comparison to regional background concentration records of the atmospheric CO2 concentration. The dependence of the passive scalars CO2 and H2O on atmospheric stability (zeta) differs distinctly in comparison to momentum and heat. The vertical fluxes of momentum (tau) and heat (QH) are actively generating mechanically and buoyantly driven turbulence, respectively. Due to the strong coupling between tau, QH and zeta, each stability class is characterized by a distinctive turbulence regime. In contrast, the turbulent exchange of CO2 and H2O is not primarily controlled by the existence of transporting eddies, but also heavily influenced by the activity and the composition of the corresponding scalar sources (e.g. traffic, heating etc.) and thus, the heterogeneity of the local surrounding. Models represent the transfer efficiencies of momentum and heat accurately while the prediction for CO2 and H2O mostly fails. Other factors, like the interplay between the activity of sources and sinks are more important and accordingly, the transfer efficiency of CO2 can be consulted to identify times or wind sectors where the source/sink regime is altered by e.g. photosynthetic activity. The inter-comparison of the transport characteristics of heat, CO2 and H2O leads to the assumption of scalar dissimilarity. By applying the quadrant analysis framework to the long-term time series, dominant turbulent structures responsible for efficient vertical exchange, i.e. coherent structures, can be identified. The length of the time series allows to extend the analysis to the stable range, which usually rarely occurs in urban areas. The variability of local urban rhoC is investigated in comparison to regional background concentration records. While patterns on daily and seasonal scales are similar, the vicinity to the ground sources of the local measurements leads to a stronger sensitivity to changes on small temporal scales. The height above ground of the background concentration measurements and thus the larger distance from the ground sources results in a phase shift of up to three months compared to the local seasonal course of rhoC. While rhoC in the urban area is also clearly elevated by 10 ppm on average, the behavior of rhoC in the urban environment reveals good consistency with background concentration measurements in terms of seasonality and long-term trend. The calculated local linear trend for the time period between 2005 and 2014 is around 2 ppm/y, which also coincides well with the global average trend. The coupling between FC and anthropogenic activity in the urban area is apparent from considerable differences in weekday and weekend fluxes, the diurnal cycle as a result of traffic volume or the seasonality caused by additional heating activity in wintertime. The variability of FC scales with the source activity and a long-term decrease of FC around 5% is observed locally as a result of a decrease in traffic activity during the investigation period. However, variabilities on all temporal scales are clearly larger than the observed long-term tendencies. For the investigation of FC in the heterogeneous urban environment an appropriate weighting between individual wind sectors is shown to be necessary due to the unequal frequency distribution of wind directions. The application of a refined methodology for the calculation of horizontally averaged fluxes of CO2 significantly improves the representativity of the data for the investigation area and also enhances the comparability of the data to results from other studies. The length of the current dataset allows to estimate the significance of the observed long-term behavior. While up to six years are potentially needed to calculate a significant inter-annual trend of rhoC, statistics of FC still benefit from even longer data records due to the larger variability. This gives evidence, that long-term time series of urban CO2 can help to add valuable knowledge to the current understanding of the urban ecosystem and its role in the global carbon balance