Biomass burning emissions estimated with a global fire assimilation system based on observed fire radiative power

The Global Fire Assimilation System (GFASv1.0) calculates biomass burning emissions by assimilating Fire Radiative Power (FRP) observations from the MODIS instruments onboard the Terra and Aqua satellites. It corrects for gaps in the observations, which are mostly due to cloud cover, and filters spurious FRP observations of volcanoes, gas flares and other industrial activity. The combustion rate is subsequently calculated with land cover-specific conversion factors. Emission factors for 40 gas-phase and aerosol trace species have been compiled from a literature survey. The corresponding daily emissions have been calculated on a global 0.5° × 0.5° grid from 2003 to the present. General consistency with the Global Fire Emission Database version 3.1 (GFED3.1) within its accuracy is achieved while maintaining the advantages of an FRP-based approach: GFASv1.0 makes use of the quantitative information on the combustion rate that is contained in the FRP observations, and it detects fires in real time at high spatial and temporal resolution. GFASv1.0 indicates omission errors in GFED3.1 due to undetected small fires. It also exhibits slightly longer fire seasons in South America and North Africa and a slightly shorter fire season in Southeast Asia. GFASv1.0 has already been used for atmospheric reactive gas simulations in an independent study, which found good agreement with atmospheric observations. We have performed simulations of the atmospheric aerosol distribution with and without the assimilation of MODIS aerosol optical depth (AOD). They indicate that the emissions of particulate matter need to be boosted by a factor of 2–4 to reproduce the global distribution of organic matter and black carbon. This discrepancy is also evident in the comparison of previously published top-down and bottom-up estimates. For the time being, a global enhancement of the particulate matter emissions by 3.4 is recommended. Validation with independent AOD and PM10 observations recorded during the Russian fires in summer 2010 show that the global Monitoring Atmospheric Composition and Change (MACC) aerosol model with GFASv1.0 aerosol emissions captures the smoke plume evolution well when organic matter and black carbon are enhanced by the recommended factor. In conjunction with the assimilation of MODIS AOD, the use of GFASv1.0 with enhanced emission factors quantitatively improves the forecast of the aerosol load near the surface sufficiently to allow air quality warnings with a lead time of up to four days

Aerosol analysis and forecast in the European Centre for Medium-Range Weather Forecasts Integrated Forecast System: 2. Data assimilation

This study presents the new aerosol assimilation system, developed at the European Centre for Medium-Range Weather Forecasts, for the Global and regional Earth-system Monitoring using Satellite and in-situ data (GEMS) project. The aerosol modeling and analysis system is fully integrated in the operational four-dimensional assimilation apparatus. Its purpose is to produce aerosol forecasts and reanalyses of aerosol fields using optical depth data from satellite sensors. This paper is the second of a series which describes the GEMS aerosol effort. It focuses on the theoretical architecture and practical implementation of the aerosol assimilation system. It also provides a discussion of the background errors and observations errors for the aerosol fields, and presents a subset of results from the 2-year reanalysis which has been run for 2003 and 2004 using data from the Moderate Resolution Imaging Spectroradiometer on the Aqua and Terra satellites. Independent data sets are used to show that despite some compromises that have been made for feasibility reasons in regards to the choice of control variable and error characteristics, the analysis is very skillful in drawing to the observations and in improving the forecasts of aerosol optical depth

Accurate mobile remote sensing of XCO₂ and XCH₄ latitudinal transects from aboard a research vessel

A portable Fourier Transform Spectrometer (FTS), model EM27/SUN, is deployed onboard the research vessel Polarstern to measure the column-average dry air mole fractions of carbon dioxide (XCO2) and methane (XCH4) by means of direct sunlight absorption spectrometry. We report on technical developments as well as data calibration and reduction measures required to achieve the targeted accuracy of fractions of a percent in retrieved XCO2 and XCH4 while operating the instrument under field conditions onboard the moving platform during a six week cruise through the Atlantic from Cape Town (South Africa, 34° S, 18° E) to Bremerhaven (Germany, 54° N, 19° E). We demonstrate that our solar tracker typically achieves a tracking precision of better than 0.05° toward the center of the sun throughout the ship cruise which facilitates accurate XCO2 and XCH4 retrievals even under harsh ambient wind conditions. We define several quality filters that screen spectra e.g. when the field-of-view is partially obstructed by ship structures or when the lines-of-sight cross the ship exhaust plume. The measurements in clean oceanic air, can be used to characterize a spurious airmass dependency. After the campaign, deployment of the spectrometer side-by-side the TCCON (Total Carbon Column Observing Network) instrument at Karlsruhe, Germany, allows for determining a calibration factor that makes the entire campaign record traceable to World Meteorological Organization (WMO) standards. Comparisons to observations of the GOSAT satellite and concentration fields modeled by the European Centre for Medium-Range Weather Forecasts (ECMWF) within the project Monitoring of Atmospheric Composition and Climate – Interim Implementation (MACC-II) demonstrate that the observational setup is well suited to provide validation opportunities above the ocean and along interhemispheric transects

Accurate mobile remote sensing of XCO₂ and XCH₄ latitudinal transects from aboard a research vessel

A portable Fourier transform spectrometer (FTS), model EM27/SUN, was deployed onboard the research vessel Polarstern to measure the column-average dry air mole fractions of carbon dioxide (XCO$_{2}$) and methane (XCH$_{4}$) by means of direct sunlight absorption spectrometry. We report on technical developments as well as data calibration and reduction measures required to achieve the targeted accuracy of fractions of a percent in retrieved XCO$_{2}$ and XCH$_{4}$ while operating the instrument under field conditions onboard the moving platform during a 6-week cruise on the Atlantic from Cape Town (South Africa, 34° S, 18° E; 5 March 2014) to Bremerhaven (Germany, 54° N, 19° E; 14 April 2014). We demonstrate that our solar tracker typically achieved a tracking precision of better than 0.05° toward the center of the sun throughout the ship cruise which facilitates accurate XCO$_{2}$ and XCH$_{4}$ retrievals even under harsh ambient wind conditions. We define several quality filters that screen spectra, e.g., when the field of view was partially obstructed by ship structures or when the lines-of-sight crossed the ship exhaust plume. The measurements in clean oceanic air, can be used to characterize a spurious air-mass dependency. After the campaign, deployment of the spectrometer alongside the TCCON (Total Carbon Column Observing Network) instrument at Karlsruhe, Germany, allowed for determining a calibration factor that makes the entire campaign record traceable to World Meteorological Organization (WMO) standards. Comparisons to observations of the GOSAT satellite and concentration fields modeled by the European Centre for Medium-Range Weather Forecasts (ECMWF) Copernicus Atmosphere Monitoring Service (CAMS) demonstrate that the observational setup is well suited to provide validation opportunities above the ocean and along interhemispheric transects

QSAR studies on a number of pyrrolidin-2-one antiarrhythmic arylpiperazinyls

The activity of a number of 1-[3-(4-arylpiperazin-1-yl)propyl]pyrrolidin-2-one antiarrhythmic (AA) agents was described using the quantitative structure–activity relationship model by applying it to 33 compounds. The molecular descriptors of the AA activity were obtained by quantum chemical calculations combined with molecular modeling calculations. The resulting model explains up to 91% of the variance and it was successfully validated by four tests (LOO, LMO, external test, and Y-scrambling test). Statistical analysis shows that the AA activity of the studied compounds depends mainly on the PCR and JGI4 descriptors

Technical note: The CAMS greenhouse gas reanalysis from 2003 to 2020

The Copernicus Atmosphere Monitoring Service (CAMS) has recently produced a greenhouse gas reanalysis (version egg4) that covers almost 2 decades from 2003 to 2020 and which will be extended in the future. This reanalysis dataset includes carbon dioxide (CO2) and methane (CH4). The reanalysis procedure combines model data with satellite data into a globally complete and consistent dataset using the European Centre for Medium-Range Weather Forecasts' Integrated Forecasting System (IFS). This dataset has been carefully evaluated against independent observations to ensure validity and to point out deficiencies to the user. The greenhouse gas reanalysis can be used to examine the impact of atmospheric greenhouse gas concentrations on climate change (such as global and regional climate radiative forcing), assess intercontinental transport, and serve as boundary conditions for regional simulations, among other applications and scientific uses. The caveats associated with changes in assimilated observations and fixed underlying emissions are highlighted, as is their impact on the estimation of trends and annual growth rates of these long-lived greenhouse gases.</p

Učinak bakra na toksičnost i genotoksičnost kadmija u vodenoj leći (Lemna minor L.)

We investigated interactions between copper (in the concentrations of 2.5 μmol L-1 and 5 μmol L-1) and cadmium (5 μmol L-1) in common duckweed (Lemna minor L.) by exposing it to either metal or to their combinations for four or seven days. Their uptake increased with time, but it was lower in plants treated with combinations of metals than in plants treated with either metal given alone. In separate treatments, either metal increased malondialdehyde (MDA) level and catalase and peroxidase activity. Both induced DNA damage, but copper did it only after 7 days of treatment. On day 4, the combination of cadmium and 5 μmol L-1 copper additionally increased MDA as well as catalase and peroxidase activity. In contrast, on day 7, MDA dropped in plants treated with combinations of metals, and especially with 2.5 μmol L-1 copper plus cadmium. In these plants, catalase activity was higher than in copper treated plants. Peroxidase activity increased after treatment with cadmium and 2.5 μmol L-1 copper but decreased in plants treated with cadmium and 5 μmol L-1 copper. Compared to copper alone, combinations of metals enhanced DNA damage after 4 days of treatment but it dropped on day 7. In conclusion, either metal given alone was toxic/genotoxic and caused oxidative stress. On day 4 of combined treatment, the higher copper concentration was more toxic than either metal alone. In contrast, on day 7 of combined treatment, the lower copper concentration showed lower oxidative and DNA damage. These complex interactions can not be explained by simple antagonism and/or synergism. Further studies should go in that direction.U svrhu istraživanja interakcija između bakra kao esencijalnog elementa te kadmija kao neesencijalnog i toksičnog metala, vodenu leću Lemna minor L. uzgajali smo na podlogama s kadmijem (5 μmol L-1) odnosno s bakrom (2,5 μmol L-1 i 5 μmol L-1) te s njihovim kombinacijama. Unos metala u biljke povećavao se s trajanjem pokusa, a kod kombinacije metala u biljkama je izmjerena niža količina kadmija nego u onima uzgajanima samo na kadmiju. U biljkama tretiranim pojedinačnim metalom došlo je do povećanja sadržaja malondialdehida (MDA) te aktivnosti katalaze i peroksidaze u odnosu na kontrolne biljke. Također, primijećeno je oštećenje DNA iako kod bakra tek sedmog dana tretmana. Količina MDA i aktivnost obaju enzima dodatno se povećala na tretmanu kombinacijom kadmija i bakra (5 μmol L-1) nakon četvrtog dana pokusa, dok se količina MDA smanjila nakon sedmog dana kod kombinacije kadmija i 2,5 μmol L-1 bakra. U tim biljkama primijećena je i veća aktivnost katalaze, dok je aktivnost peroksidaze porasla na tretmanu kadmijem i 2,5 μmol L-1 bakrom, ali se smanjila na tretmanu kadmijem i 5 μmol L-1 bakrom. Oštećenje DNA koje je bilo veće kod kombinacije metala nakon četvrtog dana, osobito u usporedbi sa samim bakrom, smanjilo se nakon sedmog dana pokusa. Iz ovih rezultata može se zaključiti da su oba metala u istraživanim koncentracijama toksična i genotoksična za vodenu leću i da uzrokuju oksidacijski stres. Kadmij u kombinaciji s bakrom više koncentracije bio je toksičniji od pojedinačnih metala nakon četvrtog dana pokusa, dok su u biljaka tretiranih kombinacijom kadmija i bakra niže koncentracije toksični učinci bili manji. Budući da su primijećene interakcije vrlo kompleksne i ne uključuju samo antagonizam odnosno sinergizam potrebna su daljnja istraživanja