/

• 02/03/2021 - Owen R. COOPER: "An update on ever-changing global tropospheric ozone trends"

  Owen R. Cooper (Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, NOAA Chemical Sciences Laboratory, Boulder)

  "An update on ever-changing global tropospheric ozone trends"

  Tropospheric ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity.  However, it is difficult to observe and quantify on the global scale, due to its acute spatial variability, resulting from its variable lifetime and its range of sources (injection from the stratosphere, or photochemical production from natural and anthropogenic precursor gases) and sinks (surface deposition and chemical destruction).

  To improve our understanding of ozone, the International Global Atmospheric Chemistry Project (IGAC) initiated the Tropospheric Ozone Assessment Report (TOAR) in 2014.  With over 230 member scientists and air quality specialists from 36 nations, TOAR’s mission is to provide the research community with an up-to-date scientific assessment of tropospheric ozone’s global distribution and trends from the surface to the tropopause.  TOAR built the world’s largest database of surface ozone observations and generated ozone exposure metrics at thousands of measurement sites around the world.  This seminar will use the results from the first phase of TOAR (2014-2019) to describe the current state of knowledge on global tropospheric ozone trends. 

  Trends will be reported for all available surface ozone monitoring sites (2000-2014), long-term monitoring sites in remote locations (1971-2018), the free troposphere (IAGOS aircraft observations, 1994-2016) and the tropospheric column (satellite products, 1979-2020).  While surface trends are highly variable, the burden of evidence points towards an increase of ozone in the northern hemisphere free troposphere, driven by increased photochemical production in the tropics.
• 09/03/2021 - Blaz GASPARINI: "Tropical anvil cloud lifecycle in present and future climate"

  Blaz Gasparini (Department of Meteorology and Geophysics, University of Vienna)

  "Tropical anvil cloud lifecycle in present and future climate"

  The evolution of anvil clouds from their origin in deep convective cores to their slow decay as thin cirrus determines the climatic effects of clouds in tropical convective regions. Despite the relevance of anvil clouds for climate, processes dominating their evolution are not well understood. We use model simulations of different complexity levels to provide a process-based perspective on anvil evolution in present and future climate. In a future warmer climate thick anvil clouds contain more ice and reflect more sunlight, which leads to more cooling, while the thin anvil clouds do not change much with warming.
• 16/03/2021 - Aitor ATENCIA: "Blending techniques at ZAMG for a seamless forecast"

  Aitor Atencia (ZAMG)

  "Blending techniques at ZAMG for a seamless forecast"

  Blending techniques are methods that merge extrapolation nowcasting with NWP in order to obtain a single seamless forecast. A new approach for obtaining a seamless forecast has been attempted by introducing the information coming from an NWP Ensemble prediction system directly into an ensemble nowcasting generator. This technique has shown benefits by not only creating realistic rainfall scenarios but also by improving the skill of the NWP-EPS.
• 23/03/2021 - Pavla WALDHAUSEROVA: "Impact of high-latitude dust on atmosphere and climate"

  Pavla Waldhauserova (The Agricultural University of Iceland, LBHI)

  "Impact of high-latitude dust on atmosphere and climate"

  High Latitude Dust (HLD) contributes 5% to the global dust budget and active HLD sources cover > 500,000 km^2 .Iceland is the largest Arctic as well as European desert with high dust event frequency (~135 dust days annually). Impacts of Icelandic dust on atmosphere, cryosphere, marine and terrestrial environments, as well as socio-economic sectors, will be introduced.
• 30/03/2021 - Lara WAGNER: "Seismic Insights into Earth's Deep Water Cycle: A story in three parts"

  Lara Wagner (Carnegie Institution for Science)

  "Seismic Insights into Earth's Deep Water Cycle: A story in three parts"
• 06/04/2021 - Vaclav KUNA: "Seismic crustal imaging using fin whale songs"

  Vaclav Kuna (Institute of Geophysics, Czech Academy of Sciences)

  "Seismic crustal imaging using fin whale songs"

  Fin whale calls are among the strongest animal vocalizations that are detectable over great distances in the oceans. We analyzed fin whale calls recorded at ocean bottom seismic stations in the northeast Pacific Ocean an show that the calls can be used for seismic imaging of the shallow oceanic crust.
• 13/04/2021 - Lucrezia TERZI: "Global and seasonal analysis of 7Be concentrations and large-scale atmospheric circulation dynamics"

  Lucrezia Terzi (Belgian Nuclear Research Centre, SCK CEN)

  "Global and seasonal analysis of 7Be concentrations and large-scale atmospheric circulation dynamics"

  Beryllium-7 (^7 Be) is a cosmogenic radionuclide formed through collision between highly energetic particles (cosmic rays) and atmospheric constituents such as oxygen and nitrogen. Once formed ^7 Be attaches to aerosol particles and is transported around the globe according to atmospheric circulation dynamics.

  This work describes how beryllium-7 can be used to predict seasonal weather and shows that decadal change patterns such as weakening of general circulation and poleward movement of Hadley cell can also be monitored effectively through such cosmogenic radionuclides. These changes may be attributable to global warming.

  Furthermore, ^7 Be is a good tracer for tropopause height changes which are presumably related to the rising of CO_2 concentrations which is also the main driver for extended summer periods.

  Near-surface measurement of cosmogenic radionuclides can help address outstanding challenges in atmospheric circulation research by integrating a new perspective across the disciplines of environmental radiation monitoring and meteorology.
• 04/05/2021 - Ivana STIPERSKI: "Extending similarity theory into complex terrain"

  Ivana Stiperski (Department of Atmospheric and Cryospheric Sciences, University of Innsbruck, ACINN)

  "Extending similarity theory into complex terrain"

  Turbulence in the atmospheric boundary layerover complex terrain is known not to follow Monin-Obukhov similarity theory (MOST) developed for flat and horizontally homogeneous terrain. The scaled data show large scatter and scaling curves are observed to be site-specific. Should we give up on MOST?

  In this talk I will discuss a novel avenue that opens a door for MOST to embrace complexity. I will show how the information on anisotropy can be used to formulate a surface layer scaling framework valid over complex terrain.

   
• 11/05/2021 - Chris MARONE: "On the Mechanics of Slow Earthquakes and Lab Earthquake Prediction"

  Chris Marone (Pennsylvania State University)

  "On the Mechanics of Slow Earthquakes and Lab Earthquake Prediction"
• 18/05/2021 - Stefan SCHNEIDER: "Soil modelling activities at ZAMG"

  Stefan Schneider (ZAMG)

  "Soil modelling activities at ZAMG"

  Zum aufgezeichneten Vortrag hier klicken: Passwort: 0D+S&*tv
• 25/05/2021 - Mostafa MOUSAVI: "How AI Changes the Way We Monitor Earthquakes"

  Mostafa Mousavi (Stanford University)

  "How AI Changes the Way We Monitor Earthquakes"
• 01/06/2021 - Sophia SCHAEFER: "Addressing radiation and cloud uncertainties with the new radiation scheme ecRad in ICON"

  Sophia Schaefer (Deutscher Wetterdienst, DWD)

  "Addressing radiation and cloud uncertainties with the new radiation scheme ecRad in ICON"

  Zum aufgezeichneten Vortrag hier klicken: Passwort: e4!9U49!

  Radiation in the atmosphere determines the energy crucial for weather and climate. Cloud-radiation interactions are particularly complex, and simplified parametrisations in models are uncertain.

  We have implemented ecRad as the new operational radiation scheme in the DWD model ICON, significantly improving model performance and energy balance. Flexible choices in ecRad allow us to analyse the uncertainty in each cloud and radiation parametrisation component.
• 08/06/2021 - Chi ZHANG: "Probing water distribution in carbonate rocks – a critical zone geophysical perspective"

  Chi Zhang (Department of Meteorology and Geophysics, University of Vienna)

  "Probing water distribution in carbonate rocks – a critical zone geophysical perspective"

  Zum aufgezeichneten Vortrag hier klicken: Passwort: Z#oj*26&

  The carbonate critical zone studies use transdisciplinary approaches to solve some of the most pressing challenges society faces (e.g., security, scarcity, and uncertainty of water, and carbon sequestration). My research uses geophysical tools, coupling with hydrogeological and biogeochemical information, via observations and modeling, to understand the pore structure, water flow, and fluid-rock interactions in the critical zone. In this talk, I will describe how I use geophysical tools, mainly geoelectric and nuclear magnetic resonance (NMR) to quantify and predict water storage and fluxes, biogeochemical fluxes, and weathering dynamics in carbonate critical zones. In addition, this talk will discuss the potential of hydrogeophysics to transform our understanding and modeling of carbonate critical zone processes.
• 15/06/2021 - Gerhard DIENDORFER: "Today's challenges in lightning location"

  Gerhard Diendorfer (ALDIS, Vienna)

  "Today's challenges in lightning location"

  Zum aufgezeichneten Vortrag hier klicken: Passwort: vCf5C.%v

  A colleague in lightning research once said "lightning detection is more of an art than a science" and that saying still holds true today. One of the biggest challenges in lightning detection is to verify the quality of the data provided, as this can only be done with real lightning in nature. The talk starts with a short overview of the different types of lightning discharges and the basic principles used for locating lightning, both with optical sensors on satellites and via the electromagnetic field, as it is done with ALDIS/EUCLID. Next methods for the distinction between cloud-to-ground (CG) and intracloud (IC) lightning are discussed and how the individual located pulses in a lightning flash are grouped. A flash often has multiple strokes in the same channel or to separate ground strike points and they need to be grouped to a lightning flash or assigned to different ground strike points. The talk will conclude with an overview and the results of performance validation of the ALDIS/EUCLID lightning detection network.

  GPS synchronized directly measured lightning discharges to the instrumented radio tower at Gaisberg near Salzburg as well as lightning flashes recorded with a high-speed camera are used as ground truth data for this validation.
• 29/06/2021 - Leonhard SCHECK: "Using solar satellite channels for data assimilation and model evaluation"

  Leonhard Scheck (Meteorologisches Institut München, LMU-MIM)

  "Using solar satellite channels for data assimilation and model evaluation".

  Zum Vortrag hier klicken.

  Geostationary satellite images provide high-resolution information on the state of the atmosphere and thus represent observations that are well-suited for convective-scale data assimilation and model evaluation. So far mainly the thermal infrared channels have been utilized for these purposes, but there is a rising interest in using also the channels in the solar part of the spectrum, which contain additional, complementary information. For instance, visible channels can provide better information on the water and ice content of clouds than thermal infrared channels, have no problems to detect low clouds and are sensitive to cloud microphysics and the cloud top structure. 

  However, only recently we developed a forward operator for visible satellite images that is sufficiently fast and accurate for operational purposes. Here we report on a new, neural network-based version that achieves higher speed and can be extended more easily. Then will discuss two ways to use the forward operator to improve forecasts. First, we show that observed and synthetic visible Meteosat SEVIRI images can be used to detect systematic errors in the model clouds that can cause severe problems for data assimilation.

  Second, based on assimilation experiments using the ICON-D2 model and the local ensemble transformation Kalman filter implemented in DWDs data assimilation coding environment (DACE) we demonstrate for test periods of several weeks that errors in the cloud distribution and the surface radiation can be significantly reduced by assimilating visible SEVIRI images.