Ozone Monitoring Instrument: system description and test results

Abstract

The Ozone Monitoring Instrument (OMI) is a nadir viewing wide field imaging spectrometer for ozone monitoring. The instrument is the Dutch/Finnish contribution to the NASA EOS-AURA mission. OMI observes earth's back scattered radiation in two spectral channels: the UV channel (270 nm-350 nm) and the VIS channel (350 nm-500 nm). Each channel employs a CCD detector (576 X 780 px). The extreme wide field of view of 114 degrees, equal to a swath width of 2600 km, is obtained by an all reflective telecentric telescope and enables global ozone coverage in one day.Other key features are the spectral range (270 nm-500 nm) and resolution (spectral sampling distance 0.15-0.32 nm/px), the application of a polarization scrambler and its compact design (400 X 300 X 500 mm). Excellent stray light performance in the UV channel is obtained by an elegant opto-mechanical design of the UV optics where the UV wavelength range is split in two parts with separate optical paths and the separate spectra are imaged on one CCD. Onboard calibration includes a white light source, LEDs, and multi-surface solar-calibration diffuser. The OMI-EOS project follows a Proto-Flight approach, supported by breadboards and engineering qualification models on parts and sub-system level. In order to increase confidence in the design, the instrument development model was built. During intensive testing critical performance parameters were checked, e.g. UV stray light behavior, polarization sensitivity, distortion, spatial and spectral ranges and resolutions.

Satellite Remote Sensing of Air Quality in the Energy Golden Triangle in Northwest China

“…The OMI-derived PCD (DU) of SO 2 and TCD (10 15 molecules cm −2 ) of NO 2 with a fine spatial and temporal resolution were collected from the NASA EOS and KNMI (Koninklijk Nederlands Meteorologisch Instituut), respectively. 15,18 The operational OMI PBL data are processed using the highly sensitive band residual difference (BRD) algorithm to facilitate the acquisition of information on nearsurface SO 2 emissions. 16 The NO 2 vertical column densities are obtained using a differential optical absorption spectroscopy (DOAS) algorithm that converts NO 2 slant column densities to vertical columns.…”

“…The OMI-derived PCD (DU) of SO 2 and TCD (10 15 molecules cm –2 ) of NO 2 with a fine spatial and temporal resolution were collected from the NASA EOS and KNMI (Koninklijk Nederlands Meteorologisch Instituut), respectively. , The operational OMI PBL data are processed using the highly sensitive band residual difference (BRD) algorithm to facilitate the acquisition of information on near-surface SO 2 emissions . The NO 2 vertical column densities are obtained using a differential optical absorption spectroscopy (DOAS) algorithm that converts NO 2 slant column densities to vertical columns. , The SO 2 PCD and NO 2 TCD have been validated against their respective monitored air concentrations in northern China. , In the present study, the OMI-retrieved column densities of SO 2 and NO 2 have been compared with the available daily and monthly ambient air concentration data of these two chemicals at official air quality monitoring stations and in the China National Environmental Monitoring Center () near the central NECIB region.…”

“…Through the use of satellite-based observations, it is possible to obtain valuable information on emissions, spatial–temporal patterns, and annual trends of many air contaminants. − In particular, air quality remote sensing with relatively high spatial resolution has been improved rapidly in the last several years. Notably, the Ozone Monitoring Instrument (OMI) on the NASA EOS Aura platform provides daily global coverage in combination with small ground pixel sizes (nominally 13 km × 24 km at nadir, minimum 13 km × 12 km at nadir) − and the Infrared Atmospheric Sounding Interferometer. − This article presents the satellite-retrieved column densities of sulfur dioxide (SO 2 ) and nitrogen dioxide (NO 2 ) as well as their trends from 2005 to 2014 over the EGT and NECIB with a high spatial resolution, aiming to fill critical knowledge gaps and understand air quality in the EGT given the shifting energy base in northern China. Awareness of the implications of these large-scale national policies are important for assessing and minimizing impacts.…”

In-operation field-of-view retrieval (IFR) for satellite and ground-based DOAS-type instruments applying coincident high-resolution imager data

“…GOME-2 features four spectroscopic main channels (science channels) between 240 and 790 nm with a spectral resolution between 0.26 and 0.51 nm. Furthermore, GOME-2 includes two polarization measurement devices (PMDs) whose measurements are clustered to 15 PMD channels each (Lang, 2010;Tilstra et al, 2011). The instrument features a maximum swath width of 1920 km scanned applying the whisk-broom approach as depicted in Fig.…”