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An analysis is presented of 3.8 years of Solar Mesosphere Explorer (SME) IR ozone data and 4.3 years of Nimbus 7 stratosphere and mesosphere sounder temperature data for the purpose of estimating and characterizing the zonal mean response of the mesosphere to solar ultraviolet variations occurring on the solar rotation time scale. In agreement with an earlier study by Keating et al. (1987) the maximum low-latitude ozone and temperature response amplitudes occur at essentially the same level (-,•0.06 mbar; approximately 68 km altitude). The ozone response is negative and occurs at nearly zero lag, while the peak temperature response is positive and occurs at a lag of 3 to 5 days. The derived ozone response sensitivities and phase lags in the lower mesosphere merge smoothly with those previously determined for the upper stratosphere using independent satellite data sets. Some evidence for a weak negative ozone response near 75 km at high winter latitudes is also obtained. Temperature perturbations at low latitudes that correlate with solar ultraviolet flux variations are connected in phase with those occurring at higher latitudes in the winter hemisphere, suggesting the existence of a dynamical component of the mesospheric response. The coexistence of positive temperature and negative ozone response maxima at the same level (-,•68 'kin) indicates strong coupling between photochemical and thermal components of the response. The negative ozone response can potentially be explained by a combination of temperature feedback from the observed temperature response and increased Lyman c• dissociation of water vapor (followed by HO z destruction of ozone). The positive temperature response cannot be due to ozone radiative heating since the ozone pertm'bation is negative. However, other heating terms, including those due to exothermic chemical reactions, are known to contribute to the mesospheric heat budget. In particular, HO z chemical heating (mainly from H + 0 3 -> OH + O2) will increase with ozone destruction and may therefore be a likely candidate mechanism. P. Fabian, pp. 380-383, A. Deepak, Hampton, Va., 1989. Hood, L. L., and J. L. Jirikowic, Stratospheric dynamical effects of solar ultraviolet variations: Evidence from zonal mean ozone and temperature data, J. Geophys. Res., 96, 7565-7577, 1991. Keating, G. M., The mesospheric responses to short-term solar ultraviolet variability, in Handbook .for Middle Atmosphere Program, vol. 29, edited by J. La•tovi•ka, part 1, p. 67, Rudder, Detection of the response of ozone in the middle atmosphere to short-term solar ultraviolet variations, Geophys. Res. Left., 1oe, 449-452, 1985. Keating G. M., J. Y. Nicholson III, D. F. Young, G. Brasseur, and A. De Rudder, Response of middle atmosphere to short-13,002 HOOD ET AL.: MESOSPHERIC EFFECTS OF SOLAR UV VARIATIONS (50-90 kin) measured by the SME Limb Scanning Near Infrared Spectrometer, Geophys. Res. Left., 10, 245-248, 1983. van Loon, H., R. A. Madden, and R. L. Jenne, Oscillations in the winter stratosphere, Part 1, Descripti...

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Two 6-L submerged anaerobic membrane bioreactors (SAMBR) with SRT of 30 and 60 d (denoted as R30 and R60, respectively) were set up and operated for five months, with a mixture of glucose as substrate. Feasibility of SAMBR was studied for treatment of low-strength wastewater. First two months were identified as acclimation stage. A COD removal efficiency was achieved stably at around 99% and biogas productions were maintained at 0.023 and 0.028 L CH4/gMLVSSd for R30 and R60, respectively. Even though R60 contained higher MLVSS concentration, no significant difference of treatment performances between both reactors was found due to the low organic loading rate and high purification function of membrane. In the investigation of membrane fouling, less irreversible fouling was observed for R30 compared to R60. High non-flocculent concentration of R60 would be responsible for membrane internal pore blocking and deteriorated effluent quality.