[1] Retrievals from the Microwave Limb Sounder (MLS) and the Ozone Monitoring Instrument (OMI) on EOS-Aura were included in the Goddard Earth Observing System version 4 (GEOS-4) ozone data assimilation system. The distribution and daily to seasonal evolution of ozone in the stratosphere and troposphere during 2005 are investigated. In the lower stratosphere, where dynamical processes dominate, comparisons with independent ozonesonde and Measurement of Ozone and Water Vapour by Airbus In-Service Aircraft (MOZAIC) data indicate mean agreement within 10%. In the troposphere, OMI and MLS provide constraints on the ozone column, but the ozone profile shape results from the parameterized ozone chemistry and the resolved and parameterized transport. Assimilation of OMI and MLS data improves tropospheric column estimates in the Atlantic region but leads to an overestimation in the tropical Pacific and an underestimation in the northern high and middle latitudes in winter and spring. Transport and data biases are considered in order to understand these discrepancies. Comparisons of assimilated tropospheric ozone columns with ozonesonde data reveal root-mean-square (RMS) differences of 2.9-7.2 Dobson units (DU), which are smaller than the model-sonde RMS differences of 3.2-8.7 DU. Four different definitions of the tropopause using temperature lapse rate, potential vorticity (PV), and isentropic surfaces or ozone isosurfaces are compared with respect to their global impact on the estimated tropospheric ozone column. The largest sensitivity in the tropospheric ozone column is found near the subtropical jet, where the ozone-or PV-determined tropopause typically lies below the lapse rate tropopause. Citation: Stajner, I., et al. (2008), Assimilated ozone from EOS-Aura: Evaluation of the tropopause region and tropospheric columns,

Solvation structures of the Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Ga(III) ions in methanol (MeOH), ethanol (EtOH), dimethyl sulfoxide (DMSO), and trimethyl phosphate (TMP) have been determined using extended X-ray absorption fine structure (EXAFS) spectroscopy. In MeOH, EtOH, and DMSO, the solvation structures of all metal(II,III) ions are 6-coordinate octahedral as in water, and the M-O bond lengths are similar to those in water. In the bulky solvent TMP, the 5-coordinate solvation structure is observed for the Zn(II) ion without ligand-field stabilization. The Ga(III) ion has the 6-coordinate solvation structure in TMP despite its smaller ionic radius than the Zn(II) ion because of the higher charge density on the Ga(III) ion. In the cases of the Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) ions, the electronic absorption spectra have been measured in MeOH, EtOH, and DMSO. All solutions for each metal(II) ion show a spectral pattern similar to that in water, which is consistent with the results of the EXAFS measurements.

Abstract. Temperature data derived from the cryogenic limb array etalon spectrometer (CLAES) on board the Upper Atmosphere Research Satellite (UARS) are used to investigate planetary-scale temperature disturbances near the equatorial stratopause for January 1992 to May 1993. The disturbances are characterized by vertically stacked temperature extrema of alternating sign with a vertical scale of about 10 km and have a localized and stationary nature in the longitudinal direction with persistence of about 1 week. These are nearly identical to so-called "pancake structures" first identified by Hitchman et al. [1987] using data from the limb infrared monitor of the stratosphere (LIMS). Their analysis suggested that pancake structures are consistent with those predicted by inertial instability theory and that their appearance is synchronized with strong planetary waves in the winter midlatitude, though the LIMS observations were made only during the northern winter. Using the CLAES data for about 14 months, this study shows that pancake structures occur not only during the northern winter but also during the southern winter. In addition, it is found that an equatorial pancake structure has its counterpart with reversed phase in the winter midlatitude, suggesting clear evidence for inertial instability. Further analyses on the basis of Ertel's potential vorticity show that inertially unstable regions intrude locally far into the winter hemisphere around pancake structures that appear when planetary wave breaking is going on. This implies a mechanism of localized inertial instability and resulting pancake structures caused by midlatitude planetary waves in the winter hemisphere, as some numerical studies have inferred. Another observational work was done by Fritts et al. [1992], using the data from mesosphere-stratosphere-troposphere (MST) radar at Jicamarca (12øS, 77øW). They found persistent features in the meridional wind component with vertical scales of 6-10 km in the mesosphere during the southern winter. Though their analysis depends on the one-point ground-based observation, they inferred that the structures are due to inertial instability.O'Sullivan and Hitchman [1992] followed up on H87 by using a mechanistic middle atmosphere model to investigate the relationship between equatorial inertial instability and midlati-19,469

Stratospheric transport calculated using assimilated winds has been shown to be too fast in many cases, because of excessive mixing and an overstrong residual circulation. It is shown that the use of 6‐h‐averaged wind fields instead of instantaneous analyses can substantially reduce this problem for NASA's Goddard Earth Observing System version 4 (GEOS‐4) sequential data assimilation system. Two examples are used to illustrate impacts in an off‐line chemistry transport model. An age‐of‐air computation shows that the stratosphere becomes substantially older when time‐averaged winds are used, yet still not as old as that determined from observations. An ozone assimilation experiment reveals improvements in the spatial structure of assimilated ozone, better agreement with independent observations, and a 40–60% reduction in observation‐minus‐forecast residuals. The averaged meteorological fields have also been incorporated in the on‐line transport computations: This is equivalent to using a 6‐h square‐wave filter at the analysis times. Sub‐6‐h noise in the system is substantially reduced with this approach. Two additional examples of transport are shown. A simulation of 2004–2005 shows that the descent of N2O in the Arctic polar vortex is represented more accurately than in previous studies. A tape recorder signal is evident in the tropical moisture; it ascends about 30% faster than that in the real atmosphere. In summary, the use of 6‐h‐averaged winds substantially improves the transport characteristics of the assimilated data, although the circulation remains too fast.