This is an important manuscript documenting performances of MethaneAIR imaging spectrometer for accurately measure emissions of CH4 from oil and gas production and processing facilities The MethaneAIR is a precursor of MethaneSAT, a small satellite intended to revolutionize measurements and modeling of emissions of CH4 at regional (100s of km) and fine scales (< 1 km), across the globe. Its deployment onboard the NSF Gulfsteam-V aircraft is an important step for validation and demonstration of MethaneSAT. The paper demonstrates the instrument's ability to quantify methane emission at various scale and concludes successfully the pre-launch validation phase of MethaneSat.

I agree with the handling aditor that this is a very useful and comprehensive study and deserves wide attention.

This manuscript provides a detailed overview of aerosol and cloud products to be expected from the upcoming EarthCARE mission. In documenting the basic steps of processing of the data from the ATLID instrument it will be a very valuable source of information for users of the resulting products.

Air pollution is one of the greatest threats to human health, and many of the adverse health effects can be attributed to aerosols. In addition, aerosols play an important role in regulating climate, both through direct effects and through cloud formation. Aerosols can be detected using satellite-based instruments, but due to the broad range of characteristics and their variability in space and time, aerosol retrieval by remote sensing is not trivial. This highlight paper presents the combination of data from six satellite instruments that complement each other. Three of the satellites are in sun-synchronous orbits (observing the whole Earth once per day) and three in geo-stationary orbit (observing a portion of the Earth several times per hour). The paper shows that by combining data from the six instruments a high-quality, consistent data set can be created with a higher combined spatio-temporal resolution and less gaps than existing data sets. The freely available new aerosol data product is provided at 30 minute resolution and on a 0.25 degree grid in a format convenient for use in satellite studies or ingestion by models, providing data that will further advance the field of aerosol studies.

I fully support the justification given by the handling editor

The manuscript presents an approach for enabling direct flux measurements of greenhouse gases to already existing tall tower networks by simply adding a 3D sonic anemometer to each station. This way, the spatial information density about the land surface exchange and quantifying temporal sources and sinks of greenhouse gases would be significantly improved with little extra instrumental effort. Slower-response analyzers may be used for flux measurements as the relevant frequency ranges at tall towers differ from those closer to the land surface. Tall tower measurements have larger footprints than classical eddy-covariance ecosystem sites, which further amplify spatial coverage of observations. Still, detailed knowledge of surrounding footprints is needed. The presented concept is of high relevance within the scientific greenhouse gas community and may act as a blueprint for bridging scales between atmospheric and ecosystem networks.

Atmospheric rivers (ARs) are recognized as significant contributors to extreme precipitation at mid-latitudes and may increase in frequency and intensity due to climate change. This timely study is the first the show the potential value of GNSS radio occultation (GNSS RO) remote sensing to the study of ARs and in particular how the high vertical resolution of GNSS RO provides information that is complementary to other techniques. The combination of GNSS-RO data with mesoscale models, particularly through assimilation, could further improve our understanding of AR dynamics and the processes leading to extreme precipitation and flooding. This is an important direction for future studies.

Chemical ionization mass-spectrometry (CIMS) has been widely used in atmospheric chemistry research to detect oxygenated organic compounds. However, accurate quantification of species which do not have generic standards remains a major challenge for CIMS application, and semi-quantitative methods which have been developed to solve this dilemma usually have very large uncertainties. This work introduced a novel classification approach which greatly enhances the accuracy of semi-quantitative methods and effectively reduces their uncertainties. Although the approach was developed in this work specifically for toluene oxidation products, the concept can also be applied to other oxygenated organic compounds and may significantly enhance the quantification ability of CIMS.