Analysis of tropospheric trace gas amounts from satellite and ship-based DOAS-type measurements : NO2 from biomass burning and other sources

Nitrogen oxides (NOx) play key roles in atmospheric chemistry, air pollution, and climate. While the largest fraction of these reactive gases is released by anthropogenic emission sources, a significant amount can be attributed to vegetation fires. Tropospheric nitrogen dioxide (NO2) amounts can be retrieved from ground-based, ship-based, aircraft-based, and satellite-based remote sensing measurements. The focus of this thesis is to analyze such NO2 measurements for the characterization of NOx from open biomass burning and other sources. In the first part of this thesis, satellite measurements of tropospheric NO2 from GOME-2 and OMI as well as fire radiative power (FRP) from the MODIS instruments are used to derive seasonally averaged fire emission rates (FERs) of NOx for different types of vegetation using a simple statistical approach. Monthly means of tropospheric NO2 vertical columns (TVC NO2) are analyzed for their temporal correlation with the monthly means of FRP for a multi-year period. The strongest correlation is found to be largely confined to tropical and subtropical regions, which account for more than 80% of yearly burned area, on average, globally. As atmospheric models typically require values for the amount of NOx being released as a function of time, the retrieved TVC NO2 is converted into production rates of NOx from fire (Pf). By separating the monthly means of Pf and FRP according to land cover type, FERs of NOx could be derived for different biomes and regions. The estimated FERs for the dominating types of vegetation burned are lowest for boreal forest, open shrublands, and savannas (0.25-1.03 g NOx s^-1 MW^-1) and highest for croplands and woody savannas (0.82-1.56 g NOx s^-1 MW^-1). This analysis demonstrates that the strong empirical relationship between TVC NO2 and FRP and the following simplified assumptions are a useful tool for the characterization of NOx emission rates from vegetation fires in the tropics, subtropics, and in boreal regions. As current fire emission inventories apply emission factors (EFs) of NOx for the translation of biomass burned into trace gas emissions, the satellite-derived FERs of NOx are converted into EFs of NOx. A comparison with NOx EFs found in the literature shows good agreement for some biomes (e.g. boreal forest, tropical forest, and crop residue). However, the EFs for savanna and grassland obtained from satellite measurements are lower by a factor of 2.5. This has possible implications for future work in this field, in particular because savanna and grassland is the most frequently burned biome on Earth. As recent satellite-based studies have indicated substantial spatio-temporal variations in NOx EFs for several biomes, a modified approach is used for the computation of monthly resolved FERs of NOx. In order to evaluate the impact when such seasonal changes are not included, a case study for the African continent to estimate total NOx emissions from open biomass burning is performed by applying both seasonally averaged and monthly resolved FERs of NOx. The results indicate differences between the two tested approaches of up to 90%, in particular on a monthly basis. In the second part of this thesis, ship-based MAX-DOAS measurements performed within the SHIVA campaign in November 2011 on board RV Sonne in the South China and Sulu Sea are analyzed. Spectral measurements for a total of eleven days are used to retrieve tropospheric slant column densities (SCDs) of NO2 and sulfur dioxide (SO2) in the marine environment. An improved NO2 fit including a cross section for liquid water and an empirical correction spectrum accounting for the effects of liquid water and vibrational Raman scattering and a novel SO2 fit are applied to the ship-based measurements. The conversion of SCDs into TVC NO2 is achieved using both a simple geometric approach and the Bremian advanced MAX-DOAS Retrieval Algorithm (BREAM), which is based on the optimal estimation method and accounts for atmospheric radiative transfer. The results show that the geometric approach using the 15 deg measurements is in good agreement with BREAM, revealing that measurements at 15 deg elevation angle can be used for retrieving TVC NO2 in tropical marine environments. As expected, the values of TVC NO2 are generally low ( 2 x 10^15 molec cm^-2) are observed in the morning when the RV Sonne was heading along the coast of Borneo. This is in good agreement with satellite measurements. Interestingly, elevated tropospheric SO2 amounts for measurements taken in a busy shipping lane are consistent with the time series of tropospheric NO2

Variabilität der Bewölkung und Auswirkungen auf die Solarstrahlung in Wien

In dieser Arbeit wird der Einfluss der Wolken auf die Solarstrahlung in Wien untersucht. Einerseits wird die an der Erdoberfläche gemessene Globalstrahlung abgeschwächt, wenn eine Wolkenschicht die sichtbare Sonnenscheibe verdeckt. Andererseits können Wolken auch dazu führen, dass sich die Globalstrahlung kurzfristig erhöht. Dieser Effekt wird als Strahlungserhöhung bezeichnet und tritt dann auf, wenn zusätzlich zum Anteil der direkten Strahlung ein durch Streuung und Reflexion an den Wolkenpartikeln erhöhter Anteil an diffuser Strahlung vom Messgerät erfasst wird. Durch die kombinierte Verwendung von Spektroradiometer und Fischaugenkamera soll das Phänomen der Strahlungserhöhung anhand von mehreren Fallbeispielen, die am Dach der Universität für Bodenkultur (BOKU) an bewölkten Tagen im Mai und Juni 2009 durchgeführt wurden, gezeigt werden. Die Globalstrahlungsdaten (10-min- Mittelwerte), die am BOKU Dach von einem Sternpyranometer seit Juli 2005 fortlaufend aufgezeichnet werden, dienen als Grundlage für eine mehrjährige statistische Analyse der Strahlungserhöhungen. Neben dem Einfluss des Zenitwinkels der Sonne wird anhand von stündlich beobachteten Bedeckungsgraden, die von der Zentralanstalt für Meteorologie und Geodynamik (ZAMG) aufgezeichnet werden, der Einfluss der Wolken untersucht. Um die Häufigkeit des Auftretens sowie das Ausmaß der Strahlungserhöhungen quantifizieren zu können, wurde mittels eines Strahlungstransfermodells eine Referenzstrahlung für wolkenlose Bedingungen geschätzt. Anhand der gemessenen und der geschätzten Globalstrahlung lässt sich sowohl das Ausmaß der relativen, als auch jenes der absoluten Strahlungserhöhungen berechnen. Die Analyse der Strahlungserhöhungen in Abhängigkeit vom Zenitwinkel der Sonne hat gezeigt, dass die Werte der absoluten (relativen) Strahlungserhöhung mit abnehmenden (zunehmenden) Zenitwinkel der Sonne zunehmen. Mit einem Wert von 269,03 W/m² (1,8) hat sich die maximale absolute (relative) Strahlungserhöhung am 5. August 2006 (16. April 2006) bei einem Zenitwinkel von 34,04° (84,11°) ereignet. Die Untersuchung des Einflusses der Bewölkung hat ergeben, dass die höchsten absoluten (relativen) Strahlungserhöhungen bei einem Bedeckungsgrad 2 von 5 Achtel (7 Achtel) auftreten. Die höchsten Werte der absoluten (relativen) Strahlungserhöhung treten folglich bei kleinen (großen) Zenitwinkeln der Sonne und höheren Bedeckungsgraden auf. Mit zunehmenden Bedeckungsgrad bei zugleich nicht verdeckter Sonne, nimmt sowohl der Anteil der diffusen Strahlung als auch jener der Globalstrahlung zu. Letztendlich geht aus dieser Studie hervor, dass Strahlungserhöhungen durch Wolken ohne weiters länger als 10 Minuten andauern können

An all-electrical torque differential magnetometer operating under ambient conditions

An all-electrical torque differential magnetometry (also known as cantilever magnetometry) setup employing piezoelectric quartz tuning forks is demonstrated. The magnetometer can be operated under ambient conditions as well as low temperatures and pressures. It extends the allowed specimen mass range up to several 10 $\mu$g without any significant reduction in the sensitivity. Operation under ambient conditions and a simple all-electrical design of the magnetometer should allow for an easy integration with other experimental setups. The uniaxial magnetic anisotropy of a 25 $\mu$m diameter iron wire, measured under ambient conditions with a high signal to noise ratio, was found to be in good agreement with its literature value. Further applications of the technique are discussed.Comment: 9 two-column pages, 9 figure

The Wooster Voice (Wooster, OH), 1946-10-04

The football team has sustained an abundance of injuries over the past week. Both staff and students are having difficulties with not have enough housing spaces, nor enough classrooms. The first year senate chair will be Don Shawver. Students have voted in favor for having a homecoming queen by 757 for and 128 against. On the thirteenth of October, the Inter-Club Council will be hosting a tea for any freshman girl who is interested in joining a section. A feature is written about how a Latin American student views the College of Wooster. Emory Anderson writes about how squirrels are slowly dominating the world.https://openworks.wooster.edu/voice1941-1950/1128/thumbnail.jp

Plastidial NAD-Dependent Malate Dehydrogenase: A Moonlighting Protein Involved in Early Chloroplast Development through Its Interaction with an FtsH12-FtsHi Protease Complex

Malate dehydrogenases (MDHs) convert malate to oxaloacetate using NAD(H) or NADP(H) as a cofactor. mutants lacking plastidial NAD-dependent MDH () are embryo-lethal, and constitutive silencing (1) causes a pale, dwarfed phenotype. The reason for these severe phenotypes is unknown. Here, we rescued the embryo lethality of via embryo-specific expression of pdNAD-MDH. Rescued seedlings developed white leaves with aberrant chloroplasts and failed to reproduce. Inducible silencing of pdNAD-MDH at the rosette stage also resulted in white newly emerging leaves. These data suggest that pdNAD-MDH is important for early plastid development, which is consistent with the reductions in major plastidial galactolipid, carotenoid, and protochlorophyllide levels in 1 seedlings. Surprisingly, the targeting of other NAD-dependent MDH isoforms to the plastid did not complement the embryo lethality of , while expression of enzymatically inactive pdNAD-MDH did. These complemented plants grew indistinguishably from the wild type. Both active and inactive forms of pdNAD-MDH interact with a heteromeric AAA-ATPase complex at the inner membrane of the chloroplast envelope. Silencing the expression of FtsH12, a key member of this complex, resulted in a phenotype that strongly resembles 1. We propose that pdNAD-MDH is essential for chloroplast development due to its moonlighting role in stabilizing FtsH12, distinct from its enzymatic function

Glyoxal tropospheric column retrievals from TROPOMI – multi-satellite intercomparison and ground-based validation

We present the first global glyoxal (CHOCHO) tropospheric column product derived from the TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel-5 Precursor satellite. Atmospheric glyoxal results from the oxidation of other non-methane volatile organic compounds (NMVOCs) and from direct emissions caused by combustion processes. Therefore, this product is a useful indicator of VOC emissions. It is generated with an improved version of the BIRA-IASB scientific retrieval algorithm relying on the differential optical absorption spectroscopy (DOAS) approach. Among the algorithmic updates, the DOAS fit now includes corrections to mitigate the impact of spectral misfits caused by scene brightness inhomogeneity and strong NO2 absorption. The product comes along with a full error characterization, which allows for providing random and systematic error estimates for every observation. Systematic errors are typically in the range of 1 ×10^14–3 ×10^14 molec. cm−2 (∼30 %–70 % in emission regimes) and originate mostly from a priori data uncertainties and spectral interferences with other absorbing species. The latter may be at the origin, at least partly, of an enhanced glyoxal signal over equatorial oceans, and further investigation is needed to mitigate them. Random errors are large ( molec. cm−2) but can be reduced by averaging observations in space and/or time. Benefiting from a high signal-to-noise ratio and a large number of small-size observations, TROPOMI provides glyoxal tropospheric column fields with an unprecedented level of detail. Using the same retrieval algorithmic baseline, glyoxal column data sets are also generated from the Ozone Monitoring Instrument (OMI) on Aura and from the Global Ozone Monitoring Experiment-2 (GOME-2) on board Metop-A and Metop-B. Those four data sets are intercompared over large-scale regions worldwide and show a high level of consistency. The satellite glyoxal columns are also compared to glyoxal columns retrieved from ground-based Multi-AXis DOAS (MAX-DOAS) instruments at nine stations in Asia and Europe. In general, the satellite and MAX-DOAS instruments provide consistent glyoxal columns both in terms of absolute values and variability. Correlation coefficients between TROPOMI and MAX-DOAS glyoxal columns range between 0.61 and 0.87. The correlation is only poorer at one mid-latitude station, where satellite data appear to be biased low during wintertime. The mean absolute glyoxal columns from satellite and MAX-DOAS generally agree well for low/moderate columns with differences of less than 1×10^14 molec. cm−2. A larger bias is identified at two sites where the MAX-DOAS columns are very large. Despite this systematic bias, the consistency of the satellite and MAX-DOAS glyoxal seasonal variability is high

Mobility in a Globalised World 2015

The term mobility has different meanings in the following science disciplines. In economics, mobility is the ability of an individual or a group to improve their economic status in relation to income and wealth within their lifetime or between generations. In information systems and computer science, mobility is used for the concept of mobile computing, in which a computer is transported by a person during normal use. Logistics creates by the design of logistics networks the infrastructure for the mobility of people and goods. Electric mobility is one of today’s solutions from engineering perspective to reduce the need of energy resources and environmental impact. Moreover, for urban planning, mobility is the crunch question about how to optimise the different needs for mobility and how to link different transportation systems. In this publication we collected the ideas of practitioners, researchers, and government officials regarding the different modes of mobility in a globalised world, focusing on both domestic and international issues

Consensus guidelines for the use and interpretation of angiogenesis assays

The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference

Satellitengestützte Erdbeobachtung - Aufgaben des Deutschen Fernerkundungsdatenzentrums im DLR

Der Beitrag gibt einen Überblick über die Möglichkeiten der Fernerkundung, Aufgaben, kommende Missionen und einige industrielle Partner des Deutschen Fernerkundungsdatenzentrums im DLR (Stand: 01/2006)