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Summertime upper tropospheric nitrous oxide over the Mediterranean as a footprint of Asian emissions
Author(s) -
Kangah Yannick,
Ricaud Philippe,
Attié JeanLuc,
Saitoh Naoko,
Hauglustaine Didier A.,
Wang Rong,
El Amraoui Laaziz,
Zbinden Régina,
Delon Claire
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd026119
Subject(s) - troposphere , environmental science , atmospheric sciences , nitrous oxide , greenhouse gas , climatology , relative humidity , meteorology , geology , geography , chemistry , oceanography , organic chemistry
The aim of this paper is to study the transport of nitrous oxide (N 2 O) from the Asian surface to the eastern Mediterranean Basin (MB). We used measurements from the spectrometer Thermal and Near infrared Sensor for carbon Observation Fourier transform spectrometer on board the Greenhouse gases Observing SATellite (GOSAT) over the period of 2010–2013. We also used the outputs from the chemical transport model LMDz‐OR‐INCA over the same period. By comparing GOSAT upper tropospheric retrievals to aircraft measurements from the High‐performance Instrumented Airborne Platform for Environmental Research Pole‐to‐Pole Observations, we calculated a GOSAT High‐performance Instrumented Airborne Platform for Environmental Research standard deviation (SD error) of ~2.0 ppbv for a single pixel and a mean bias of approximately −1.3 ppbv (approximately −0.4%). This SD error is reduced to ~0.1 ppbv when we average the pixels regionally and monthly over the MB. The use of nitrogen fertilizer coupled with high soil humidity during the summer Asian monsoon produces high N 2 O emissions, which are transported from Asian surfaces to the eastern MB. This summertime enrichment over the eastern MB produces a maximum in the difference between the eastern and the western MB upper tropospheric N 2 O (east‐west difference) in July in both the measurements and the model. N 2 O over the eastern MB can therefore be considered as a footprint of Asian summertime emissions. However, the peak‐to‐peak amplitude of the east‐west difference observed by GOSAT (~1.4 ± 0.3 ppbv) is larger than that calculated by LMDz‐OR‐INCA (~0.8 ppbv). This is due to an underestimation of N 2 O emissions in the model and to a relatively coarse spatial resolution of the model that tends to underestimate the N 2 O accumulation into the Asian monsoon anticyclone.