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.

Following the handling editor recommendation, the manuscript presents innovative analysis of a ground-based imaging experiment using a shortwave infrared spectral camera to quantify carbon dioxide (CO2) emissions from a coal-fired power plant. The innovation of the manuscript is to use low spectral resolution (7nm) imaging spectroscopy to measure CO2 plume structure and estimate emission amounts from chimneys by the ground-based observation. The methodology has potential important applications for fine-scale estimates of CO2 and other GHG emissions

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.

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

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.