ICAM Online Event, 8 to 10 June 2021, 16:00 to 19:00 CEST

To bridge the gap between the ICAM 2019 in Riva del Garda, Italy, and the ICAM 2023 in St. Gallen, Switzerland, we organise an ICAM Online Event from 8 to 10 June 2021 to allow for the international community interested in Alpine meteorology and climatology to (virtually) meet and exchange despite the restrictions due to the ongoing Corona pandemic.

The first two days (08 and 09.06.2021) will start at 16:00 CEST (14:00 UTC) with three invited talks followed by discussion sessions in separate breakout rooms for each invited talk to allow for an active Q&A session and a lively exchange on the broader topic covered by the invited talk.

The third hour of the first two days offers the possibility to discuss topics of special interest to the ICAM community. This topical sessions will be chaired by the individuals or groups that proposed the topics to be discussed.

Finally, day three (10.06.2021) will allow for a reporting-out from the topical sessions and a general wrap-up.

Programme and Timetable

Tuesday, 8 June 2021

16:00

16:10 -
16:35

16:35 -
17:00

17:00 -
17:25

17:25 - 17:30

17:30 - 17:55

17:55 - 18:00

18:00

Wednesday, 9 June 2021

16:00

16:10 -
16:35

16:35 -
17:00

17:00 -
17:25

17:25 - 17:30

17:30 - 17:55

17:55 - 18:00

18:00

Thursday, 10 June 2021

17:00 - 17:10

17:10 - 17:35

17:35 - 18:00

18:00 - 18:25

Reporting-out topical session D & discussion

18:50 - 19:00

List of Topical Sessions

A) Surface layer scaling over complex terrain: Observations, theories, open questions
Co-chairs: Dino Zardi and Ivana Stiperski
Wednesday only; 18:00-19:00 CEST

Scaling arguments are a very helpful approach to represent properties of turbulence processes in the atmospheric boundary layer that cannot be explicitly solved in closed form. Scaling laws have been successfully derived for the simplest cases of flat horizontal terrains, such as the well known Monin-Obukhov similarity theory. However mountainous terrains offer a variety of situations, arising from a combination of different landforms, stability conditions, and basic mechanisms involved (e.g. thermally vs. dynamically driven processes). Hence atmospheric  boundary layer processes over mountainous terrain are controlled by a variety of situations that can hardly be satisfactorily reproduced by scaling relationships derived for flat terrains. In particular, the surface layer is crucially controlled by the heterogeneities of surface properties. Hence, significant departures from homogeneity or isotropy properties are very likely to be found. Within the intricacy of such a variability, is it still possible to identify, at least for some "prototypal'' situations  (e.g. simple slopes, valleys, basins, ...), typical quantities that allow to build scaling laws valid for a fairly broad variety of cases?

18:00 - Introduction
18:05 - Miguel Teixeira, University of Reading, UK: "Insights into surface layer turbulence over mountainous terrain from RDT and the upper ocean”
18:15 - Ivana Stiperski, University of Innsbruck, Austria: "Anisotropy and surface layer scaling"
18:25 - Holly J. Oldroyd, University of California at Davis, USA: "Turbulence Structure of Alpine Anabatic Winds"
18:35 - Dino Zardi, University of Trento, Italy: "A proposal for investigating thermally-driven slope winds under the programme TEAMx "
18:40 - Open discussion
19:00 - End of the session

B) Real-case large-eddy simulation over complex orography: Motivations, experiences, challenges
Co-chairs: Juerg Schmidli and Stefano Serafin
Tuesday only; 18:00 - 19:30 CEST

Today, increased availability of massively parallel computers and porting of numerical weather prediction codes to GPUs makes it possible to run models at km-scale resolution operationally on continental domains. Real-case simulations over regional domains with horizontal grid spacing in the large-eddy-simulation range, 100 to 10 m, remain demanding but are no longer an unreasonable proposition.
Successful real-case LES experiments so far dealt either with very limited domains and extended runtimes (e.g., the one-year LES over the Cabauw observational supersite in the Netherlands with GALES), or with larger domains and short forecast ranges (e.g., the collection of HD(CP)2 simulations over large parts of Germany with ICON-LEM). In these cases, the simulation domains had a lower boundary of moderate orography. Documented real-case LES runs over steep and complex orography are still very few.

We invite interested scientists to contribute and discuss their experience on any theoretical and practical aspect of real-case LES over mountainous terrain. Topics may include for instance: limitations of terrain-following grids; level of maturity of NWP codes with immersed-boundary methods; accurate specification of land use, vegetation and soil state; dealing with nested domains and developing realistic turbulence at domain boundaries; requirements in terms of physical parameterizations (e.g., 3D sub-grid-scale turbulence, 3D radiative exchange); interpretation and generalization of results.
We would further welcome  discussion on how real-case LES output can be set to profitable use. After using tens of millions of core hours for one run, what can we use it for, and how? We encourage debate on practical applications, including for instance: term of reference for parameterization development; nature runs in observing system simulation experiments; guidance for the siting of measuring equipment; driving of Lagrangian transport models.

18:00 - Branko Kosovic: Subfilter scale modeling and surface layer parameterizations: Challenges and opportunities for large-eddy simulations over complex terrain
18:12 - Tina Katopodes Chow: Getting down to 10-m resolution LES over complex terrain
18:24 - Julian Quimbayo Duarte: Drivers of particulate air pollution events in a deep Alpine valley during the wintertime
18:36 - Brigitta Goger: Large-eddy simulations with WRF of boundary-layer processes over a large Alpine glacier
18:48 - Alexander Gohm: Large-eddy simulations of foehn in the Inn Valley: Motivation, experiences and challenges during PIANO
19:30 - End of the session

C) Machine learning applications for alpine meteorology: Recent advances and future opportunities
Chair: Thomas Chen
Tuesday only; 18:00 - 19:30 CEST

With the rise in the availability and importance of big data, machine learning approaches in the field of meteorology, including specifically in the alpine regions, have rapidly become more prevalent in the scientific literature. Artificial intelligence is a fast-changing field, with deep learning techniques (with important applications in computer vision) popularized in the last decade. Weather and climate forecasting using machine learning approaches has been shown to enhance conventional statistical techniques. Methods break down into a few major categories, including now-casting, short-range weather prediction, medium-range prediction, sub-seasonal forecasting, seasonal forecasting, and climate-change prediction. In this session, we raise the questions, will artificial intelligence totally replace numerical models? If not, how can they supplement or enhance the performance and results of traditional mathematical models? How can we continue to prioritize domain-specific knowledge in interdisciplinary collaborations? In this scope, the answer to these questions can be different for the various subareas of study within meteorological modelling. For instance, “Hard AI” refers to applications in which predictions on the corresponding timescales can be largely or completely replaced by artificial intelligence; in this case, physical constraints, like conservation laws, are able to be ignored as marginal errors that do not accumulate to a significant level over time. Mobile phone data is an excellent source of data for this purpose, as it provides a large database of information to work with, which is necessary for machine learning. In general, a wide range of machine learning algorithms and models have use cases in alpine meteorology, from linear regression, to random forest ensembles (RFs), to convolutional neural networks (CNNs), to generative adversarial networks (GANs).

D) Remote sensing of the boundary layer over complex terrain: Advances, opportunities and challenges
Co-chairs: Bianca Adler and Nevio Babić
Wednesday only; 18:00 - 19:00 CEST

The atmospheric boundary layer over complex terrain is highly variable in space and time and the exchange of mass, momentum, moisture, and energy is affected by processes spanning a wide range of scales from millimeters to kilometers. This wide range of scales and the considerable variability pose challenges for capturing decisive processes and structures experimentally, since continuous area wide measurements with appropriate high spatial and temporal resolution are needed. Recent advances in active and passive ground-based remote sensing opened up new possibilities to better capture the three-dimensional structure in the boundary layer. Ground-based remote sensing may enhance our understanding of thermally and dynamically driven boundary layers, the interaction of slope and valley winds as well as the initiation of moist convection and may provide invaluable data sets for model evaluations.

In this topical session, we invite interested scientists to share and discuss their experience on remote sensing observations. Possible topics may include: multi-Doppler lidar applications to study mean and turbulent flow characteristics, temperature and humidity profiling from active and passive sensors, how to address the heterogeneity and non-stationarity of the flow, practical considerations for the deployment in complex terrain (e.g., site locations, backscatter capabilities). We also welcome discussions on how to combine different remote sensors and get the optimal information content from instrument synergies and what we can gain from airborne remote sensing instruments.

18:00 - Introduction
18:05 - Nevio Babić: Coupling multiple Doppler LiDARs for studying wind dynamics in complex terrain
18:15 - Philipp Gasch: Airborne Doppler lidar for boundary layer research in complex terrain
18:25 - Bianca Adler: Thermodynamic profiling of the boundary layer
18:35 - Neil Lareau: Ka-band observations during prescribed fires
18:45 - Open discussion
19:00 - End of the session

Registration

Registration ended on Friday 28.05.2021.

The link to the Online Event will be provided by e-mail to all registered participants a few days before the event.