Tropospheric Emissions: Monitoring of Pollution (TEMPO).

TEMPO was selected in 2012 by NASA as the first Earth Venture Instrument, for launch between 2018 and 2021. It will measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO observes from Mexico City, Cuba, and the Bahamas to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution (~2.1 km N/S×4.4 km E/W at 36.5°N, 100°W). TEMPO provides a tropospheric measurement suite that includes the key elements of tropospheric air pollution chemistry, as well as contributing to carbon cycle knowledge. Measurements are made hourly from geostationary (GEO) orbit, to capture the high variability present in the diurnal cycle of emissions and chemistry that are unobservable from current low-Earth orbit (LEO) satellites that measure once per day. The small product spatial footprint resolves pollution sources at sub-urban scale. Together, this temporal and spatial resolution improves emission inventories, monitors population exposure, and enables effective emission-control strategies. TEMPO takes advantage of a commercial GEO host spacecraft to provide a modest cost mission that measures the spectra required to retrieve ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), formaldehyde (H2CO), glyoxal (C2H2O2), bromine monoxide (BrO), IO (iodine monoxide),water vapor, aerosols, cloud parameters, ultraviolet radiation, and foliage properties. TEMPO thus measures the major elements, directly or by proxy, in the tropospheric O3 chemistry cycle. Multi-spectral observations provide sensitivity to O3 in the lowermost troposphere, substantially reducing uncertainty in air quality predictions. TEMPO quantifies and tracks the evolution of aerosol loading. It provides these near-real-time air quality products that will be made publicly available. TEMPO will launch at a prime time to be the North American component of the global geostationary constellation of pollution monitoring together with the European Sentinel-4 (S4) and Korean Geostationary Environment Monitoring Spectrometer (GEMS) instruments.

Extractive FTIR spectroscopy with cryogen-free low-temperature inert preconcentration for autonomous measurements of atmospheric organics: 1: Instrument development and preliminary performance.

In collaboration with the Jefferson County Department of Health and the Environmental Protection Agency (EPA), the University of Alabama in Huntsville developed a novel sensor for detecting very low levels of volatile organic compounds (VOCs). This sensor uses a commercial Fourier-transform infrared (FTIR) spectrometer, a commercial long-path IR gas cell, a commercial acoustic Stirling cyrocooler, and a custom cryogen-free cryotrap to improve sensitivity in an autonomous system with on-board quality control and quality assurance. Laboratory and initial field results show this methodology is sensitive to and well-suited for a wide variety of VOC atmospheric research and monitoring applications, including EPA National Air Toxics Trends Stations and the National Core monitoring network.

Comparison of scan-angle method and convective cloud differential method in retrieving tropospheric ozone from TOMS.

Tropospheric ozone, derived from the Scan-Angle Method (SAM) and the Convective Cloud Differential (CCD) method, exhibits a noticeable abundance over the South Atlantic, where it is associated with biomass-burning in the austral spring. This feature is also seen in the distribution of carbon monoxide observed from Measurements Of Pollution In The Troposphere (MOPITT). In the boreal burning season, however, the distribution of the results from SAM and MOPITT-CO present an enhancement related to the biomass-burning over North Africa that does not appear in the CCD results. The relationship of the results from SAM and MOPITT-CO is better than those of the results from the CCD and MOPITT-CO for the December-February period. Conversely, the latter relationship is better than the former for the October-November period. The two methods, SAM and CCD, show higher correlation in the southern burning season, but lower correlation in the northern burning season. The influence of biomass burning on ozone amounts is clearly seen in the SAM results of the elevated ozone over northern equatorial Africa during the northern burning season, but is not present in the CCD results.