לוח שנה משולב

Satellite instruments, such as TROPOMI, are routinelyused to quantify tropospheric nitrogen dioxide (NO2)based on its narrowband light absorption in the UV/visible spectral range. The key limitation of suchretrievals is that they can only return the „verticalcolumn density“ (VCD), defined as the integral of theNO2 concentration profile. The profile itself, whichdescribes the vertical distribution of NO2, remainsunknown.This presentation showcases „NitroNet“, the first NO2profile retrieval for TROPOMI. NitroNet is a neuralnetwork, which was trained on synthetic NO2 profilesfrom the regional chemistry and transport model WRFChem,operated on a European domain for the month ofMay 2019. The neural network receives NO2 VCDs fromTROPOMI alongside ancillary variables (meteorology,emission data, etc.) as input, from which it estimates NO2concentration profiles.The talk covers:• an introduction to satellite remote sensing of NO2.• the theoretical underpinnings of NitroNet, how themodel was trained, and how it was validated.• practical new applications that NitroNet enables.

Prof. Orr Spiegel from TAU studies animal movement

Two-dimensional materials are atomically thin crystals with a huge variety of physico-chemical properties. By stacking such materials into heterostructures we can combine the electrical, optical, and vibrational excitations of different materials with atomic control over their interfaces. Despite the great selection of 2D materials existing today, we desire novel routes for their preparation in addition to cleaving them from layered bulk parent compounds.In this talk I discuss a concept for novel 2D materials from organic molecules: Growing molecules into well-defined 2D and 1D lattices. We prepared 2D lattices of flat aromatic molecules using hexagonal boron nitride and graphene as atomically smooth substrates. The molecules are well separated in space and oriented side-by-side so that electrons and vibrations are confined to the individual building blocks. However, the interaction between their optical and vibrational transition dipole moments gives rise to collective states that can propagate inside the lattices. One-dimensional molecular lattices are grown by filling carbon- and boron-nitride nanotubes leading to giant J aggregates inside the tubes. We discuss how to use molecular lattices for advance molecular-2D-material heterostructures and how to manipulate their emergent optical excitations.