ALBERT

Description: This dataset contains the processed and raw data collected with the Backscatter Cloud Probe with Polarization Detection during the HALO-AC³ campaign in March and April 2022 with the Polar 6 Aircraft out of Longyearbyen, Svalbard. The dataset contains two kinds of data. Data to which no inversion procedure has been applied and data to which the inversion procedure has been applied. The inversion procedure is applied to account for an uneven intensity of the laser beam across the sample area and resulting undersizing effects. The inversion procedure has been discussed in Lucke et al. (2023) (doi.org/10.4271/2023-01-1485) and Beswick et al. (2014) (doi.org/10.5194/amt-7-1443-2014). All quantities which carry the suffix inv are based on the inverted data, all other properties are not. It should be noted, that the necessity of the inversion procedure remains unclear (see the previously mentioned publications). The inversion procedure could only be applied when more than 2000 particles were present over a 5 second interval. When this was not the case, the inverted data are 9999.999. The inverted data are therefore also computed from a 5s rolling average. The measurements of the BCPD are likely severely influenced by inertial separation effects, due to the proximity of the BCPD sample area to the fuselage (approx. 3cm). When ice particles are present, shattering occurs on the fuselage and artificially increases the ice number concentration. The number of ice and liquid particles listed in this data set can be useful for assessing the presence of ice and liquid particles. To estimate the number of liquid and ice particles more than 100 particles are required over a 5s interval. When this is not the case, the data are 9999.999. The number of ice and liquid particles were computed as rolling averages over 5s intervals. The sample area in case no inversion procedure is applied is 0.273 square millimeters.

Description: During the HALO-(AC)³ campaign performed in March/April 2022, broadband solar and thermal-infrared irradiances in the vicinity of Svalbard were measured by pairs of CMP22 (0.2-3.6 µm) and CGR4 (4.5-42 µm) radiometers (Kipp&Zonen), respectively, onboard Polar 5 and Polar 6. The data set contains time series of both upward and downward solar and thermal-infrared irradiances obtained during in total 26 research flights (13 with each aircraft). All irradiances were corrected for instrument inertia (Ehrlich and Wendisch, 2015), the solar downward irradiance additionally for the aircraft attitude (Bannehr and Schwiesow, 1993). Since the latter correction is only valid for cloud-free conditions dominated by direct illumination, both a corrected and an uncorrected version are given. A rough cloud flag is included in the data set to distinguish between situations dominated by direct and diffuse illumination. To avoid too large uncertainties, the attitude flag can be used to filter situations with aircraft attitude angles (roll, pitch) exceeding 5°. Additionally, obvious icing and large temperature gradients, which disturb the thermal equilibrium between sensor and instrument body, are flagged. The data set further contains the solar downward irradiance simulated for cloud-free conditions and the upward brightness temperature measured by the KT-19 infrared thermometer (HEITRONICS, 9.6-11.5 µm).

Description: We investigated the spatio-temporal trajectories of mountain agro-ecosystems by studying five lakes located between 880 and 2440 m a.s.l. in the north-western Alps. More specifically, we were interested in past interactions between agropastoral activities, plant community composition and erosion dynamics. To investigate this question, we relied on a multi-proxy dataset of lake sediment analyses. The selected proxies come mainly from plant and mammal sedimentary DNA analyses, but also from pollen and spore analyses of coprophilous fungi (Sporormiella sp.). The originality of this dataset is the creation of an index of (agro-)pastoral activity intensity valid for each lake catchment. This index showed a pattern of development of (agro-)pastoral activities according to altitude in this Alpine region. This index was then used to analyse the impact of (agro)pastoral activities on erosion dynamics and plant cover.

Description: This data set consists of in-situ measurements carried out aboard the Polar 6 research aircraft during HALO-AC3 campaign in March/April 2022. This comprises the aerosol properties of arctic ambient aerosol particle (outside cloud) and cloud particle residual (inside cloud) and the cloud water content / water vapor. The measurements were carried out north-west and west of Svalbard using the CVI inlet together with the PSAP, CPC, UHSAS aerosol instruments and the WVSS-II hygrometer of the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany.

Description: The Pliocene Epoch (~2.6–5.3 million years ago, Ma) was characterized by a warmer than present climate with smaller Northern Hemisphere ice sheets, and therefore offers an example of a climate system in long-term equilibrium with current or predicted near-future carbon dioxide concentrations. The end of the Pliocene (~2.6 Ma) is marked by further ice-sheet expansion and intensification of glacial (cold) stages, referred to as the "intensification of Northern Hemisphere Glaciation" (iNHG). Here we present the data used to assess the spatial and temporal variability of ocean temperatures and ice-volume indicators through the late Pliocene and early Pleistocene (from 3.3 to 2.4 Ma) to determine the character of this climate transition. The data come from the Atlantic, Pacific, Indian and Southern Ocean, as well as some marginal seas. Here we present the synthesized alkenone sea-surface temperature, Mg/Ca sea-surface temperature, planktonic foraminifera d18O and benthic foraminifera d18O data which were used in our synthesis. Although the original data sets are largely published, here we present the alkenone SST records calculated using the BAYSPLINE calibration where these were not part of the original publication; the Mg/Ca-SST records where we revised the absolute SSTs; any data sets where we revised the age model.