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11.C - Other Natural Sources
Short description
Within NFR 11.C - Other Natural Sources: Other, natural activities and resulting emissions other than volcanoes (11.A) and forest fires (11.B) are to be taken into account.
The 2023 EMEP/EEA Guidebook distinguishes the following emission sub-categories of NFR 11.C - Natural Sources: Other:
| NFR 11.C sub-categories |
|---|
| Other natural sources: Non-managed & managed forests |
| Other natural sources: Natural grassland and other vegetation |
| Other natural sources: Wetlands and waters |
| Other natural sources: Animals |
| Other natural sources: Geological seepage |
| Other natural sources: Forest & grassland soils |
| Other natural sources: Lightning |
| Other natural sources: Changes in forest and other woody biomass stock |
| Other natural sources: Forest and grassland conversion |
| Other natural sources: Abandonment of managed land |
| Other natural sources: CO2 from or removal into soil |
| Other natural sources: Other |
However, for the time being, from the natural sources listed above, only emissions from lightning is taken into account in the German emissions inventory.
NOTE: As NFR 11.C is a memo item category, emissions reported here are not accounted for in the National Totals.
Other natural sources: Lightning
For the time being, the only natural emission source reported within NFR 11.C is lightning.
| Category Code | Method | AD | EF |
|---|---|---|---|
| 11.C | T1 | NS | D |
|
|
|||
| NOx | NMVOC | SO2 | NH3 | PM2.5 | PM10 | TSP | BC | CO | Heavy Metals | POPs | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| -/- | NA | NA | NA | NA | NA | NA | NA | NA | NA | NA | ||||||||
| This memo item source category is not included in the key category analysis. | ||||||||||||||||||
Lightning (and corona discharge) during thunderstorm events cause atmospheric chemical reactions to take place at high voltages and high temperatures. These reactions cause the production of NOx in the atmosphere.
Methodology
The calculation of NOx emissions from lightning uses strike counts from the German weather service and default emission factors from the 2023 EMEP/EEA guidebook 1).
For the complete time series, the emissions are calculated as follows:
EM = AD (number of lightning strikes) * EF (kg emission per strike)
Activity data
The number of lightning strikes in Germany is taken from a commercial system called “BLIDS” run by Siemens. The data has been cross-referenced with information from the German weather service. Consistent strike count data is available from 1992 onward and has been back-populated to cover the full time series since 1990. The following table shows the strike figures over time.
Table 1: Annual number of lightning strikes in Germany, as 1990, in [1,000 strikes]
| 1990 | 1995 | 2000 | 2005 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 443 | 394 | 1,026 | 802 | 589 | 687 | 656 | 542 | 623 | 550 | 432 | 443 | 446 | 329 | 399 | 512 | 242 | 316 |
Emission factor(s)
For the calculation of emissions in this category, the Guidebook emission factor of 2.75 kg NOx per strike is used.
Emission Trend
The emission value is solely dependent on the strike count and varies between 1 to 3 kilotons of NOx per year.
Figure 1: NFR 11.C, NOx emissions from lightning
Recalculations
With activity data and emission factors remaining unrevised, no recalculations were carried out compared to the previous submission.
Uncertainties
The AD from BLIDS does have a low uncertainty of ± 3%. The uncertainties for the emission factors are estimated to be relatively high, being a default value. Hence the overall uncertainty for the emission estimation of NOx from lightning is qualified estimated by expert judgement to be high (>50%).
Planned Improvement
At the moment, no source-specific improvements are planned.