Hydrophobins are surface-active fungal proteins that adsorb to the water–air interface and self-assemble into amphiphilic, water-repelling films that have a surface elasticity that is an order of magnitude higher than other molecular films. Here we use surface-specific sum-frequency generation spectroscopy (VSFG) and site-directed mutagenesis to study the properties of class I hydrophobin (HFBI) films from Trichoderma reesei at the molecular level. We identify protein specific HFBI signals in the frequency region 1200–1700 cm–1 that have not been observed in previous VSFG studies on proteins. We find evidence that the aspartic acid residue (D30) next to the hydrophobic patch is involved in lateral intermolecular protein interactions, while the two aspartic acid residues (D40, D43) opposite to the hydrophobic patch are primarily interacting with the water solvent.

<p>For the validation of Sentinel-5p/TROPOMI the TROpomi vaLIdation eXperiment (TROLIX) was held in the Netherlands based at the Cabauw Experimental Site for Atmospheric Research during September 2019. TROLIX consisted of active and passive remote sensing platforms in conjunction with several balloon-borne and surface measurements.</p><p>The intensive observations will serve to establish the quality of TROPOMI L2 main data products (UVAI, Aerosol Layer Height, NO<sub>2</sub>, O<sub>3</sub>, HCHO, Clouds) under realistic conditions with varying cloud cover and a wide range of atmospheric conditions.</p><p>Since TROPOMI is a hyperspectral imager with a very high spatial resolution of 3.6 x 5.6 km<sup>2</sup>, understanding local effects such as inhomogeneous sources of pollution, sub-pixel clouds and variations in ground albedo is important to interpret TROPOMI results. Therefore, the campaign included sub-pixel resolution local networks of sensors, involving MAXDOAS and Pandora instruments, around Cabauw (rural) and within the city of Rotterdam (urban). Utilising its comprehensive in-situ and remote sensing observation program in and around the 213 m meteorological tower, Cabauw was the main site of the campaign with focus on vertical profiling using lidar instruments for aerosols, clouds, water vapor, tropospheric and stratospheric ozone, as well as balloon-borne sensors for NO<sub>2</sub> and ozone.</p><p>The data set collected can be directly compared to the TROPOMI L2 data products, while measurements of parameters related to a-priori data and auxiliary parameters that infuence the quality of the L2 products such as aerosol and cloud profiles and in-situ aerosol and atmospheric chemistry were also collected.</p><p>This paper gives an overview of the campaign, and an overview of the participating main and ancillary instrumentation and preliminary results.</p><p>Future activities include the deployment in 2020 of an airborne hyperspectral imager.</p>

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Recent Earth Observation instruments require a highly accurate knowledge of their Instrument Spectral Response Function (ISRF). This translates into lengthy and costly characterisation programs during the Assembly, Integration, and Test phase of the instrument. In addition, potential changes of ISRF after launch suggests to use an on-board equipment dedicated to this accurate characterisation in flight. This topic has been studied by Thales Alenia Space and TNO in the frame of a TRP study funded by ESA during years 2019 and 2020. This paper first recalls the potential application cases and the related target performances of the study. Then we identify conceptual solutions, such as operating tuneable laser diodes, Fabry-Perot interferometer, microresonators. Next, we describe the principle of the selected solution: a Fourier Transform Spectrometer (FTS), used as a calibration light source. Indeed, a single FTS can cover a very large spectral range with an extremely high spectral accuracy. But FTS are known as complex and sensitive devices: we have designed a simplified solution, well adapted to space applications.In a second step, we describe the flight hardware designed by Thales Alenia Space, targeting optimised manufacturing and implementation. The main performances, being spectral resolution and signal to noise ratio (SNR), are discussed. Breadboard activities also took place in TNO in order to validate the main hypotheses. Innovative data processing has been tested, that only makes use of interferogram data, while maintaining a high accuracy. Description of the breadboard as well as the first test results are presented.