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Interannual variations of stratospheric water vapor over 1992–2003 are studied using Halogen Occultation Experiment (HALOE) satellite measurements. Interannual anomalies in water vapor with an approximate 2-yr periodicity are evident near the tropical tropopause, and these propagate vertically and latitudinally with the mean stratospheric transport(More)
Recent in situ measurements at tropical tropopause temperatures as low as 187 K indicate supersat-urations with respect to ice exceeding 100% with little or no ice present. In contrast, models used to simulate cloud formation near the tropopause assume a supersaturation threshold for ice nucleation of about 65% based on laboratory measurements of aqueous(More)
In situ measurements of the relative humidity with respect to ice (RHi) and of nitric acid (HNO3) were made in both natural and contrail cirrus clouds in the upper troposphere. At temperatures lower than 202 kelvin, RHi values show a sharp increase to average values of over 130% in both cloud types. These enhanced RHi values are attributed to the presence(More)
Tropical stratospheric water vapor measured by the microwave limb sounder (M 1.S), " Geophys. Comparison of C1O measurements made by airborne and spaceborne microwave radiometers in the arctic winter stratosphere 1993, " Geophys. Correlated ollservations of HC1 and C1ONO2 from UARS and implications for stratospheric chlorine partitioning, " Geophys. Res.(More)
Stratospheric water vapor concentrations decreased by about 10% after the year 2000. Here we show that this acted to slow the rate of increase in global surface temperature over 2000-2009 by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases. More limited data suggest that stratospheric water vapor(More)
Kazakhstan (Fig. 4E). These mountain waves are present at all heights, reaching the uppermost levels of the stratosphere (Fig. 4C). There is also evidence of more isolated mountain wave activity over the Alps and the Alaska-Yukon region. Mountain waves are largely absent in both the observations and model results over other mountainous regions, such as(More)
We have developed a chemical ionization mass spectrometry technique for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere (UT) were often near or below the detection limit of the measurements (0.005 parts per billion by volume),(More)
WB‐57F aircraft flew 26 science flights during TC4. The ER‐2 employed 11 instruments as a remote sampling platform and satellite surrogate. The WB‐57F used 25 instruments for in situ chemical and microphysical sampling in the tropical tropopause layer (TTL). The DC‐8 used 25 instruments to sample boundary layer properties, as well as the radiation,(More)