Belmonte Rivas M.,Technical University of Delft |
Belmonte Rivas M.,Royal Netherlands Meteorology Institute |
Veefkind P.,Technical University of Delft |
Veefkind P.,Royal Netherlands Meteorology Institute |
And 3 more authors.
Atmospheric Chemistry and Physics | Year: 2015
We derive annual and seasonal global climatologies of tropospheric NO2 profiles from OMI cloudy observations for the year 2006 using the cloud-slicing method on six pressure levels centered at about 280, 380, 500, 620, 720 and 820 hPa. A comparison between OMI and the TM4 model tropospheric NO2 profiles reveals striking overall similarities, which confer great confidence to the cloud-slicing approach to provide details that pertain to annual as well as seasonal means, along with localized discrepancies that seem to probe into particular model processes. Anomalies detected at the lowest levels can be traced to deficiencies in the model surface emission inventory, at mid-tropospheric levels to convective transport and horizontal advective diffusion, and at the upper tropospheric levels to model lightning NOx production and the placement of deeply transported NO2 plumes such as from the Asian summer monsoon. The vertical information contained in the OMI cloud-sliced NO2 profiles provides a global observational constraint that can be used to evaluate chemistry transport models (CTMs) and guide the development of key parameterization schemes. © 2015 Author(s).
De Laat A.T.J.,SRON Netherlands Institute for Space Research |
De Laat A.T.J.,Royal Netherlands Meteorology Institute |
Gloudemans A.M.S.,SRON Netherlands Institute for Space Research |
Aben I.,SRON Netherlands Institute for Space Research |
Schrijver H.,SRON Netherlands Institute for Space Research
Journal of Geophysical Research: Atmospheres | Year: 2010
This paper presents a detailed global comparison of Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) and Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO) column measurements for the years 2004 and 2005. Qualitatively, spatiotemporal variations of SCIAMACHY and MOPITT are similar. Quantitative comparisons have been performed taking the effects of instrument noise errors, vertical sensitivities via the averaging kernel and a priori, different spatiotemporal sampling and clouds into account using simulated CO profiles from the TM4 model. SCIAMACHY and MOPITT CO columns are similar over tropical, subtropical, and Northern Hemisphere oceans as well as over boreal regions where SCIAMACHY and MOPITT agree to within 10% or 2 × 1017 molecules/cm 2. The short-wave infrared SCIAMACHY observations also provide information about lower tropospheric COin Arctic and subarctic regions north of 60°N, where the MOPITT sensitivity is strongly reduced. South of 45°S, SCIAMACHY CO columns are 3-5 × 1017 molecules/cm2 smaller than MOPITT CO columns. Approximately 1.5 × 1017 molecules/cm2 (∼10%) of this difference is attributed to a bias in the SCIAMACHY CO columns, which is currently under investigation. The remaining difference is possibly related to MOPITT biases in this region. In the transition from oceans to dry desert regions, MOPITT CO total columns show a rapid increase of approximately 3 × 1017 molecules/cm2 (∼15%). While MOPITT and SCIAMACHY agree over oceans, MOPITT is approximately 5 × 1017 molecules/cm2 (∼25%) larger than SCIAMACHY results over dry land regions. The origin of this bias needs further investigation. Copyright 2010 by the American Geophysical Union.