Publishing Network for Geoscientific and Environmental Data
Not a member yet
441201 research outputs found
Sort by
Coloured dissolved organic matter absorption of filtered samples from sea ice cores from the coastal zone of the southern Canadian Beaufort Sea, near Herschel Island - Qikiqtaruk
No full textFor DOC and CDOM absorption, samples were filtered through a 0.7 μm glass fibre filter (Whatman GF/F syringe filter) which had been rinsed with 20 mL sample water. DOC samples were collected in 20 ml glass vials with septum lid, acifdified with HCl to pH < 2 and stored at 4°C until analysis. DOC was measured with a Shimadzu TOC-V analyzer. CDOM samples were collected in 100 mL amber glass bottles that were stored in the dark at 4°C until analysis. aCDOM was measured at the German Research Center for Geosciences (GFZ), Potsdam, Germany using a double beam LAMBDA 950 UV/Vis (PerkinElmer) spectrophotometer. The absorbance (A) was measured between 200 and 800 nm in 1 nm steps using a 5 cm cuvette. Absorption (a) was calculated from the resulting absorbance measurements via aCDOM(λ) = 2.303 * A(λ) / l, where l is the path length (length of cuvette in meter). Every 5 to 10 samples, the reference sample (Milli-Q water) was exchanged and a blank was measured to avoid instrument drift. Spectral slopes (S275-295, S350-400) as well as the Slope Ratio (SR = S275-295/S350-400) were derived using the linear regression slope of the log-transformed (natural logarithm) absorption spectra (Helms et al. (2008). Specific UV absorbance (SUVA) is defined as the UV absorbance of a water sample at a given wavelength normalized for dissolved organic carbon (DOC) concentration. SUVA254 is defined as the UV absorption at 254 nm divided by the DOC concentration measured in mg L-1 (Weishaar et al., 2003). Spectral slope, Slope Ratio and SUVA were only calculated for data from filtered samples as these parameters purely depend on dissolved matter properties. CDOM absorption spectra from unfiltered aliquots of the same sample might still be of interest as they provide insight into bulk optical properties, which are crucial for total absorption budgets and remote sensing algorithms that do not distinguish dissolved vs particulate absorption
Sub-daily meteorological series of Riva del Garda (1872-1915), Station Exchange Format (SEF)
No full textThe station of Riva, established in June 1869, was one of the synoptic (or first-order) stations of Austria-Hungary and the only one in South Tyrol. Synoptic stations sent their data to the central meteorological office in Vienna once a day via telegraph to be used for weather forecast. The data were retransmitted to other European weather services and, starting from 1872, were also published on the yearbooks of the K.K. Central-Anstalt für Meteorologie and Geomagnetismus, from where the data have been digitized. The following variables are provided: temperature, daily maximum temperature, daily minimum temperature, pressure, relative humidity, cloud cover, wind intensity and direction, precipitation amount and type. Most variables (except daily extremes and precipitation) were measured three times per day. The instruments were provided by the Central-Anstalt (weather service) and were read manually by the director of the local gymnasium. The barometer was periodically compared with a standard reference, therefore the quality of the measurements was very high even by today's standard. However, thermometers at the time were insufficiently shielded from radiation, causing warm biases in certain situations. The measurements were discontinued with the war declaration of Italy on Austria-Hungary in May 1915, as Riva laid directly on the front line
Radiocarbon and thermogravimetric analysis (TGA) results of leached permafrost from the Lena Delta, Arctic
No full textThis datasheet includes radiocarbon and thermogravimetric analysis (TGA) results of the remaining permafrost after leaching from samples collected in the Lena Delta. The leaching protocol followed Ksionzek et al. (2018). Around 200 mg of dried sediment was leached in 20 mL deionized water for 24 hours at 4 °C, with intermittent shaking every 6−8 hours. After extracting the leachate, the remaining fraction was again freeze-dried. Pretreatment and measurement of radiocarbon analysis on the permafrost remainder followed Mollenhauer et al., 2021. Sediments were freeze-dried, ground, and weighed into silver boats, with sample sizes determined by TOC content to target 1 mg of organic carbon. Samples were acidified with three drops of 6 M HCl at 60 °C three times with one hour reaction time between treatments, then oven-dried overnight at 60 °C. Afterwards, acidified samples together with silver boats were folded into tin boats and converted into graphite targets using an elemental analyzer (Elementar vario Isotope) coupled to an automated graphitization system (Ionplus AG, AGE-3). Radiocarbon measurements were conducted using the MIni CArbon Dating System (MICADAS) accelerator mass spectrometer at Alfred Wegener Institute (AWI). For TGA analysis, about 20 mg of the remained permafrost were analyzed in 70 μL aluminum oxide crucibles using a Mettler Toledo TGA/DSC 1. The samples were heated from 25 to 1000 °C at a rate of 10 °C min-1 under a constant argon flow of 20 mL min-1, following similar settings from Smeaton & Austin (2022). Following Lopez-Capel et al. (2006), weight loss between 200–400 °C is attributed to the decomposition of labile organic matter (OML), while weight loss between 400–650°C corresponds to the decomposition of recalcitrant and refractory organic matter (OMR). The percentage of labile organic matter (OML/OM) is calculated as [OML/(OML+OMR)]*100
In-situ aircraft measurements of wind farm wake effects during the AWAKEN campaign in Oklahoma (September 2023), flight AWAKEN_20230906_1209
No full textThe AWAKEN (American WAKE ExperimeNt) aircraft measurement campaign was conducted in September 2023 to investigate the interactions between wind farms and the atmospheric boundary layer (ABL) in the Southern Great Plains of Oklahoma, USA. The campaign involved 20 research flights conducted close to hub height using the research aircraft Cessna F406 with call sign D-ILAB of TU Braunschweig. Parts of the flight patterns were aligned perpendicular to the prevailing wind direction downwind of the wind farms King Plains and Armadillo Flats. These flights were designed to capture the effects of stable atmospheric conditions on wind speed and turbulence during early morning hours. In addition to flight legs perpendicular to the wind direction, vertical profiles up to an altitude of 1 km were included regularly to investigate atmospheric stability and wind profiles, in particular the phenomenon of low level jets. The resulting data include wind speed, turbulence intensities, and temperature distributions at different altitudes and distances from the wind farms. These measurements complement stationary data and provide valuable insights into the spatial and temporal variability of the wind field and vertical atmospheric stratification downwind of onshore wind farms. The dataset aims to improve wake models and optimize energy production from wind farms. This dataset is part of a broader effort to enhance power output prediction and ensure network stability with increasing reliance on variable renewable energy sources. The participation of the research aircraft of TU Braunschweig in the AWAKEN experiment was funded by the Klaus Tschira Stiftung GmbH (Germany) under Contract No. 03.006.2023
In-situ aircraft measurements of wind farm wake effects during the AWAKEN campaign in Oklahoma (September 2023), flight AWAKEN_20230922_1217
No full textThe AWAKEN (American WAKE ExperimeNt) aircraft measurement campaign was conducted in September 2023 to investigate the interactions between wind farms and the atmospheric boundary layer (ABL) in the Southern Great Plains of Oklahoma, USA. The campaign involved 20 research flights conducted close to hub height using the research aircraft Cessna F406 with call sign D-ILAB of TU Braunschweig. Parts of the flight patterns were aligned perpendicular to the prevailing wind direction downwind of the wind farms King Plains and Armadillo Flats. These flights were designed to capture the effects of stable atmospheric conditions on wind speed and turbulence during early morning hours. In addition to flight legs perpendicular to the wind direction, vertical profiles up to an altitude of 1 km were included regularly to investigate atmospheric stability and wind profiles, in particular the phenomenon of low level jets. The resulting data include wind speed, turbulence intensities, and temperature distributions at different altitudes and distances from the wind farms. These measurements complement stationary data and provide valuable insights into the spatial and temporal variability of the wind field and vertical atmospheric stratification downwind of onshore wind farms. The dataset aims to improve wake models and optimize energy production from wind farms. This dataset is part of a broader effort to enhance power output prediction and ensure network stability with increasing reliance on variable renewable energy sources. The participation of the research aircraft of TU Braunschweig in the AWAKEN experiment was funded by the Klaus Tschira Stiftung GmbH (Germany) under Contract No. 03.006.2023
In-situ aircraft measurements of wind farm wake effects during the AWAKEN campaign in Oklahoma (September 2023), flight AWAKEN_20230927_1215
No full textThe AWAKEN (American WAKE ExperimeNt) aircraft measurement campaign was conducted in September 2023 to investigate the interactions between wind farms and the atmospheric boundary layer (ABL) in the Southern Great Plains of Oklahoma, USA. The campaign involved 20 research flights conducted close to hub height using the research aircraft Cessna F406 with call sign D-ILAB of TU Braunschweig. Parts of the flight patterns were aligned perpendicular to the prevailing wind direction downwind of the wind farms King Plains and Armadillo Flats. These flights were designed to capture the effects of stable atmospheric conditions on wind speed and turbulence during early morning hours. In addition to flight legs perpendicular to the wind direction, vertical profiles up to an altitude of 1 km were included regularly to investigate atmospheric stability and wind profiles, in particular the phenomenon of low level jets. The resulting data include wind speed, turbulence intensities, and temperature distributions at different altitudes and distances from the wind farms. These measurements complement stationary data and provide valuable insights into the spatial and temporal variability of the wind field and vertical atmospheric stratification downwind of onshore wind farms. The dataset aims to improve wake models and optimize energy production from wind farms. This dataset is part of a broader effort to enhance power output prediction and ensure network stability with increasing reliance on variable renewable energy sources. The participation of the research aircraft of TU Braunschweig in the AWAKEN experiment was funded by the Klaus Tschira Stiftung GmbH (Germany) under Contract No. 03.006.2023