Intermediate conclusions

Pre industrial run

Some miscellaneous characteristics:

• GES configuration,
• 39 vertical layers, resolution 144x142,
• from fictives years 1970 to 2015,
• no anthropogenic emissions,
• BBG emissions stayed at 1850 (as well as aircraft).

Quantities to remember:

• Total N₂O loss: 10.73 TgN/y
• Total N₂O emissions: 10.73 TgN/y
• Burden : 1368 TgN

CEDS emissions for N₂O (and NH₃)

Exploration of inventories

• Bouwman Inventory :
  1. 846 N₂O emission measurements in agricultural fields and 99 measurements for NO emissions
  2. The data set includes literature reference; location of the Measurement; climate; soil type, texture, organic C content, N content, drainage, and pH; residues left in the field; crop; fertilizer type; N application rate; method and timing of fertilizer application; NH₄+ application rate (for organic fertilizers), N₂O/NO emission/denitrification (expressed as total over the measurement period, as % of N rate, and as % of N rate accounting for control); measurement technique; length of measurement period; frequency of the measurements; and additional information, such as year/season of measurement, information on soil, crop or fertilizer management, specific characteristics of the fertilizer used, and specific weather events important for explaining the measured emissions.
  3. global gridded (1°x1° resolution) data bases of soil type, soil texture, NDVI (vegetation indices) and climate.
  4. global emission thus calculated is 6.8 Tg N₂O-N y-1. The tropics (± 30° of the equator) contribute 5.4 Tg N₂O-N y-1 and the emission from extra-tropical regions (poleward of 30°) is 1.4 Tg N₂O-N y-1 .

• Transcom Inventory :
  1. "Emissions from natural soils (6–7 TgN yr −1 ) account for 60–70 % of global N2O emissions (Syakila and Kroeze, 2011; Zaehle et al., 2011). The remaining 30–40 % of emissions is from oceans (4.5 TgN yr −1 )"
  2. Five different inversion frameworks (chemistry transport model) : MOZART4 (2.5° × 1.88°), ACMt42167 (2.8° × 2.8°), TM3 (5.0° × 3.75°), TM5 (6.0° × 4.0°), LMDZ4 (3.75° × 2.5°).
  3. Data set from Orchidee O-CN, Pisces, edgar-4.1, gfed-2 and from different category (terrestrial biosphere, ocean, waste water, solid waste, solvents, fuel prod, ground transport, industry combustion, residential and other combustion, shipping, biomass burning)

• Values of N₂O emissions per inventory :

(MtN/yr)	Ocean	Land	Total	(MtN2O/yr)	Ocean	Land	Total
Bouwman	3.595	7.531	11.126	xxx	5.650	11.835	17.485
Transcom	4.222	10.573	14.795	xxx	6.634	16.614	23.248
Piscidee	3.962	7.107	11.069	xxx	6.226	11.168	17.394

• Comparison between Incasflx outputs and masks on NetCDF files:

	- Output INCASFLX -			- Notebook computing (FracMask?) -			- Notebook computing (0/1 Mask) -
(MtN2O/yr)	Ocean	Land	Ratio O/L	Ocean	Land	Ratio O/L	Ocean	Land	Ratio O/L
Bouwman	5.6505	11.835	0.478	6.58	10.945	0.6012	5.973	11.552	0.517
	32.3%	67.7%		37.6%	62.4%		34.1%	65.9%
Transcom	6.634	16.614	0.399	8.879	14.421	0.616	8.118	15.184	0.535
	28.5%	71.5%		38.1%	61.9%		34.8%	65.2%
Piscidee	6.226	11.168	0.557	6.651	10.782	0.617	6.095	11.339	0.538
	35.8%	64.2%		38.2%	61.8%		34.9%	65.1%

General remarks: Variable for Bouwman = fn2o_oce & fn2o_soil. Land emissions > Ocean emissions. Ocean emissions ~ 6 Mt/yr. Land emissions -> differences because of different period (pre-industrial & nowadays). Per line, Ocean+Land are equal independently of the calculation made.