RIVM investigates potential of satellites in measuring nitrogen emissions

RIVM and other parties, including TNO and Wageningen University & Research, are investigating the added value of satellite observations in calculating nitrogen deposition on Dutch nature reserves over the next four years. RIVM reports this in a (Dutch) press release.

The consortium is also investigating whether ‘ensemble modeling’, the application of multiple models simultaneously, reduces uncertainties in nitrogen calculations. Currently, RIVM uses a combination of computer models and field measurements from the National Air Quality Monitoring Network (LML).

Nitrogen oxides

A satellite measures air concentration in the column of air between the satellite and the ground. These measurements are made worldwide on a daily basis. They can be used to derive ground concentrations nationwide. For nitrogen oxides ( NOx (Nitrogen Oxides)), the TropOMI satellite instrument already currently provides useful data. Ammonia is measured with other satellite instruments, such as IASI and CriS. Satellite measurements can also be used to evaluate mathematical models and, for example in combination with the models, for estimates of actual emissions. 

Satellite measurements improve models

The consortium is investigating whether, and if so how, satellite data are an optimal complement to ground measurements. This is because satellites do not directly measure nitrogen deposition on soil. Satellites therefore cannot replace existing nitrogen monitoring in the Netherlands. However, satellites can provide valuable information about the sources and distribution of nitrogen compounds. This can be used to improve models. 

Multiple calculation models

Performing calculations using multiple computational models is called ensemble modeling. By using multiple models, a better understanding of the uncertainties of the calculations can be obtained. The combined picture of an ensemble often turns out to provide a better air quality forecast than individual models. By identifying the most uncertain parts of the models, targeted work can be done to improve them. This is likely to enable better deposition estimates.

Scientifically based

The research program follows on the report of the Advisory Committee on Measuring and Calculating Nitrogen (Hordijk Committee). According to this committee, the use of multiple models and the integration of satellite measurements can potentially better identify and reduce uncertainties in measurements and calculations of nitrogen deposition. Satellite measurements provide greater spatial coverage of ammonia and nitrogen oxide concentrations and thus complement well the stations in the national monitoring network. With this additional information, deposition estimates can be improved. 

The nitrogen debate shows it again: collective amnesia overrules our capable individual minds

Most of us have seen it before: the cartoon of a man tapping away frantically at his keyboard.