Assessment of the uncertainties in the NO2 and O3 measurements by visible spectrometers

摘要: The column amounts of nitrogen dioxide (NO2) and ozone (O3) were measured using a visible spectrometer based on the twilight zenith-sky technique at two observatories located similar latitudes in northern part Japan separated by distance 150 km. measurements began April 1991 Moshiri Observatory (44.4°N, 142.3°E) 1994 Rikubetsu (43.5°N, 143.8°E). Since weather conditions possible influence from tropospheric pollution not always identical these observatories, overall accuracy was studied comparing data sets. first year obtained solar zenith angle 90 degrees indicated that NO2 slant values sunrise sunset agreed within 0.36 0.54 × 1016 cm-2, respectively, corresponding to 5 % (June) 12 (December) columns. O3 0.76 1019 4 (March) ∼6 (August) columns, although difference systematic. also compared those Dobson Sapporo 143.8°E), whose latitude is observatories. When an air mass factor 17.5 used, two-year vertical with direct sun 15 Units, or 3 ∼ 6 column. between found be due partly change caused seasonal day-to-day changes shape profiles. These results confirm reliability spectrometers sites for Network Detection Stratospheric Change (NDSC).