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.

Measuring reactive nitrogen emissions from point sources using visible spectroscopy from aircraft

Accurate measurements of nitrogen dioxide (NO2), a key trace gas in the formation and destruction of tropospheric ozone, are important in studies of urban pollution. Nitrogen dioxide column abundances were measured during the Texas Air Quality Study 2000 using visible absorption spectroscopy from an aircraft. The method allows for quantification of the integrated total number of nitrogen dioxide molecules in the polluted atmosphere and is hence a useful tool for measuring plumes of this key trace gas. Further, we show how such remote-sensing observations can be used to obtain information on the fluxes of nitrogen dioxide into the atmosphere with unique flexibility in terms of aircraft altitude, and the height and extent of mixing of the boundary layer. Observations of nitrogen dioxide plumes downwind of power plants were used to estimate the flux of nitrogen oxide emitted from several power plants in the Houston and Dallas metropolitan areas and in North Carolina. Measurements taken over the city of Houston were also employed to infer the total flux from the city as a whole.

Fossil-fueled power plants as a source of atmospheric carbon monoxide

Elevated carbon monoxide (CO) mixing ratios in excess of those derived from emissions inventories have been observed in plumes from one gas- and coal-fired power plant and three of four lignite coal-fired electric utility power plants observed in east and central Texas. Observations of elevated CO on days characterized by differing wind directions show that CO emissions from the lignite plants were relatively constant over time and cannot be ascribed to separate sources adjacent to the power plants. These three plants were found to be emitting CO at rates 22 to 34 times those tabulated in State and Federal emissions inventories. Elevated CO emissions from the gas- and coal-fired plant were highly variable on time scales of hours to days, in one case changing by a factor of 8 within an hour. Three other fossil-fueled power plants, including one lignite-fired plant observed during this study, did not emit substantial amounts of CO, suggesting that a combination of plant operating conditions and the use of lignite coal may contribute to the enhanced emissions. Observed elevated CO emissions from the three lignite plants, if representative of average operating conditions, represent an additional 30% of the annual total CO emissions from point sources for the state of Texas.

Artificial activation of porcine oocytes matured in vitro

These studies were undertaken to understand the biological basis of artificially induced activation of meiotic metaphase II oocytes and to develop a source of oocytes as recipients for cloning by nuclear transfer. In vitro matured porcine oocytes were pulsed with various voltages of electricity and evaluated for pronuclear formation. The percentage of eggs that activated was significantly greater for the higher voltages. The effect on activation of the temperature of the ovaries returning from the abattoir was evaluated and it was found that oocytes derived from ovaries returning at 29 degrees C activated at lower rates (45.5%) than those returning at 36 degrees C (78.9%). An experiment was designed to evaluate the pH of electroporation medium (EM) and the duration of exposure to EM on activation. Oocytes were placed in EM at various pHs for 5 minutes, pulsed, and immediately removed to TL-Hepes or allowed an additional 2 minutes in EM prior to rinsing in TL-Hepes. The results indicate an optimum activation rate at a pH of 7.0 and allowing the additional 2 minutes in EM. Additional glucosamine (5 mM) had no affect on development of the oocyte to metaphase but reduced the percent pronuclear formation from 61% and 47%. A final experiment evaluated the developmental competence of oocytes subjected to a optimum combination of the above treatments and illustrated that a significant portion of the activated oocytes can show limited signs of cleavage. Thus in vitro matured pig oocytes can be induced to activate at high rates.

Muscle fibre size and number following immobilisation atrophy

Muscle fibre number and cross sectional area were studied in the response to immobilisation atrophy of the long head of the triceps brachii. Following eight weeks of immobilisation, fibre number of the muscle from the immobilised limb was compared to that of the contralateral control limb in six rats. Mean fibre cross sectional area of the LHT from the immobilised limb was compared to that of the contralateral control for another six animals. Atrophy, as estimated by a decrease in wet muscle weight, was 38.0% for the group used for fibre number estimations and 45.7% for the group used for fibre area. Fibre counts revealed no difference between muscles from immobilised and control limbs. Mean fibre area was 42.1% less for the muscle from the immobilised limb compared to the control limb. The results of this study indicate that atrophy of the LHT produced by immobilisation of the forelimb is the result of atrophy of the muscle fibres without a decrease in muscle fibre number.