Table. 1. Means, medians, and change rates for NO2, HCHO, and O3 concentrations in the lowest layer (altitude of 0–1 km) retrieved from MAX-DOAS observations at Chiba and Tsukuba, Japan, for 2013–2019. The change rates and determination coefficient (R2) were calculated by a linear least-squares fit. Statistics for the 8 months of March to October, when MAX-DOAS O3 data were available, are given. For NO2 and HCHO, statistics for 12 months are also given in brackets
From: Continuous multi-component MAX-DOAS observations for the planetary boundary layer ozone variation analysis at Chiba and Tsukuba, Japan, from 2013 to 2019
Species | Location | Mean (ppbv) | Median (ppbv) | Change rate (ppbv/year) | Change rate (%/year) | R2 |
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NO2 | Chiba | 3.6 (4.1) | 3.6 (4.1) | -0.2 (-0.3) | -6 (-7) | 0.50 (0.76) |
Tsukuba | 1.6 (1.9) | 1.5 (1.9) | -0.1 (-0.1) | -6 (-5) | 0.48 (0.65) |
HCHO | Chiba | 2.0 (1.7) | 2.2 (1.7) | -0.2 (-0.1) | -10 (-6) | 0.83 (0.67) |
Tsukuba | 2.8 (2.2) | 2.8 (2.1) | ±0.0 (±0.0) | ±0 (±0) | 0.17 (0.03) |
O3 | Chiba | 47 | 47 | +0.5 | +1 | 0.28 |
Tsukuba | 49 | 50 | -0.1 | ±0 | 0.37 |