THE DIGITAL ELEVATION MODEL INTERCOMPARISON EXPERIMENT DEMIX, A COMMUNITY-BASED APPROACH AT GLOBAL DEM BENCHMARKING

Water quality modeling is essential for understanding and mitigating water quality deterioration in river networks due to agricultural and industrial pollution. Improving the availability and usability of open data is vital to support global water quality modeling efforts. The GRQA extends the spatial and temporal coverage of previously available water quality data and provides a reproducible workflow for combining multi-source water quality datasets.

The Land Use/Cover Area frame Survey (LUCAS) is a regular in situ land cover and land use ground survey exercise that extends over the whole of the European Union. A new LUCAS module specifically tailored to Earth observation was introduced in 2018: the LUCAS Copernicus module. This paper summarizes the LUCAS Copernicus survey and provides the unique resulting data: 58 426 polygons with level-3 land cover (66 specific classes including crop type) and land use (38 classes).

Light reflected by Earth’s surface is different in each direction: it appears brighter or darker in certain viewing directions. Currently this effect is not accounted for in satellite retrievals; thus surface reflectance climatologies and cloud fractions show an east-west bias across orbits (GOME2,OMI). The effect for NO₂ measurements in partly cloudy scenes is substantial. We recommend that this effect in UV/Vis sensors coherently accounted for, and will be especially beneficial for TROPOMI.

We present an assessment of the predicted information content and retrieval errors for ¹³CH₄ retrieval from the planned GOSAT-2 satellite, assuming a wide range of land surface conditions. Retrieval of this quantity may allow for estimation of methane source types (e.g. biological or non-biological) based on the δ¹³C metric. We conclude that GOSAT-2 can be used for this purpose (to an accuracy of 10 ‰) assuming sufficient spatial (regional) and temporal (at least monthly) averaging.

Observational data sets of cloud characteristics are of key importance in climate science for reducing uncertainty when predicting the future state of the Earth's climate. Here we present a composite method of observing cloud from the Advanced Along Track Scanning Radiometer, employing both radiometric and geometric approaches. Using this method we find improved accuracy for resolving the cloud top height for very-low and high clouds accompanied by small changes in the microphysical parameters.