Sedimentation in Brackwasserhäfen

Das Heft 150 der Mitteilungsreihe des Instituts für Wasserbau und Wasserwirtschaft der TU Darmstadt behandelt das Thema "Sedimentation in Brackwasserhäfen". Insbesondere spielt dabei das Mobilitätscerhalten feinkörniger und zum Teil auch kohäsiver Sedimente eine zentrale Rolle

Skillful decadal prediction of German Bight storm activity

We evaluate the prediction skill of the Max Planck Institute Earth System Model (MPI-ESM) decadal hindcast system for German Bight storm activity (GBSA) on a multiannual to decadal scale. We define GBSA every year via the most extreme 3-hourly geostrophic wind speeds, which are derived from mean sea-level pressure (MSLP) data. Our 64-member ensemble of annually initialized hindcast simulations spans the time period 1960–2018. For this period, we compare deterministically and probabilistically predicted winter MSLP anomalies and annual GBSA with a lead time of up to 10 years against observations. The model produces poor deterministic predictions of GBSA and winter MSLP anomalies for individual years but fair predictions for longer averaging periods. A similar but smaller skill difference between short and long averaging periods also emerges for probabilistic predictions of high storm activity. At long averaging periods (longer than 5 years), the model is more skillful than persistence- and climatology-based predictions. For short aggregation periods (4 years and less), probabilistic predictions are more skillful than persistence but insignificantly differ from climatological predictions. We therefore conclude that, for the German Bight, probabilistic decadal predictions (based on a large ensemble) of high storm activity are skillful for averaging periods longer than 5 years. Notably, a differentiation between low, moderate, and high storm activity is necessary to expose this skill

Interne Veränderungskommunikation als Dialog zwischen direkt und indirekt Beteiligten - Ein deskriptives Modell zur internen Veränderungskommunikation

Das Ziel des Artikels ist es, ein deskriptives Modell der internen Veränderungskommunikation zu entwickeln, welches auf literarischen Klassikern der Kommunikationswissenschaft, Unternehmenspsychologie, Soziologie sowie der Managementlehre basiert. Die Autoren des Artikels vertreten mit dem Modell die Meinung, dass nur durch den Einbezug des dialogorientierten Ansatzes eine erfolgversprechende Veränderungskommunikation gelingen kann. Der Dialog zwischen direkten und indirekten Beteiligten, also zwischen Veränderungsstrategen und der Unternehmenskommunikation auf der einen sowie der restlichen Mitarbeiter auf der anderen Seite, muss während der gesamten Veränderung geführt werden und das gestiegene Informationsbedürfnis aller Beteiligten befriedigen können. An oberster Stelle steht hierbei die kommunikative Vermittlung von Sinn und Erklärungen für die Veränderung. Hierfür bedarf es zwingend der Einteilung der indirekt Beteiligten in die Untergruppen: Vorantreiber, Unterstützer, Skeptiker und Gegenspieler, die allesamt in die Veränderungskommunikation einbezogen werden sollten. Der Artikel versteht Kommunikation als sozial konstruierten Prozess der Sinnesdeutung. Er richtet sich an forschende Akademiker und Mitarbeiter in Unternehmen, die zur Gruppe der „Direkt Beteiligten“ gehören und ein Verständnis dafür entwickeln möchten, wie eine effektive Kommunikation im Wandel erfolgen kann

Seasonal Prediction of Arabian Sea Marine Heatwaves

Marine heatwaves are known to have a detrimental impact on marine ecosystems, yet predicting when and where they will occur remains a challenge. Here, using a large ensemble of initialized predictions from an Earth System Model, we demonstrate skill in predictions of summer marine heatwaves over large marine ecosystems in the Arabian Sea seven months ahead. Retrospective forecasts of summer (June to August) marine heatwaves initialized in the preceding winter (November) outperform predictions based on observed frequencies. These predictions benefit from initialization during winters of medium to strong El Niño conditions, which have an impact on marine heatwave characteristics in the Arabian Sea. Our probabilistic predictions target spatial characteristics of marine heatwaves that are specifically useful for fisheries management, as we demonstrate using an example of Indian oil sardine (Sardinella longiceps)

Poseidon Berichte - Paphsanias Volcano Cruise POS512, 25.04.2017 – 06.05.2017, Heraklion (Griechenland) – Heraklion (Griechenland)

Summary Cruise POS512 was scheduled for ten working days from 25.4. to 6.5.2017 in order to (1) produce a bathymetric map of the Epidavros Basin near the peninsula of Methana, (2) survey the volcanic structures of the Paphsanias Volcanic Field with the ROV PHOCA, and (3) sample the volcanic rocks. The Paphsanias Volcanic Field was found in 1987 but only one rock sample had been recovered and the size, age and composition of the lavas were unknown. Historic reports suggested an eruption on Methana and potentially off the coast some 2000 years ago. The bathymetric survey showed that six volcanic structures form the volcanic field ranging from simple lava flows on the seafloor, small cone-like structures to relatively complex crater-like structures with small volcanic domes. The largest volcanoes are about 200 m high and have diameters of about 2 km. The northern two complex Volcanoes 1 and 2 are relatively young and consist of steep lava flows and dome-like structures with little sediment. No indication of very young volcanism and hydrothermal activity was found. In contrast, the four southern structures are mostly sediment-covered and outcrops of volcanic rocks are rare and often covered by thick carbonate and MnOOH crusts. These four edifices are older than the northern two. Lava samples range from olivine-bearing basalts to plagioclase-amphibole-biotite-phyric andesites and dacites. All lavas appear to be fresh but few show signs of submarine extrusion and quenching. Volcaniclastic material was rarely observed and sampled indicating that explosive volcanic activity did not occur. During cruise POS512 13 ROV dives recovered 163 samples including 131 fresh lavas from four different volcanoes of the Paphsanias Volcanic Field and 427 nm of bathymetric survey was carried out

POS511 Cruise Report, The Christiana-Santorini Volcanic Complex, 01.04.2017 (Heraklion) - 22.04.2017 (Heraklion)

R.V. POSEIDON Cruise No.: 511 Dates, Ports: 01.04.2017 (Heraklion) - 22.04.2017 (Heraklion) Research Subject: The Christiana-Santorini Volcanic Comple

POS511 Cruise Report, The Christiana-Santorini Volcanic Complex, 01.04.2017 (Heraklion) - 22.04.2017 (Heraklion)

R.V. POSEIDON Cruise No.: 511 Dates, Ports: 01.04.2017 (Heraklion) - 22.04.2017 (Heraklion) Research Subject: The Christiana-Santorini Volcanic Comple