Atmospheric temperature structure during the Western European Winter Anomaly Campaign 1975/76

Ground‐based observations of atmospheric density profiles to 92 km were obtained for four successive seasons between summer 1989 and spring 1990. These results were obtained with a powerful Rayleigh lidar facility located at Wright Patterson Air Force Base (Dayton, Ohio). This instrument combined a 14‐W XeF laser transmitter with a 2.54‐m receiver mirror to observe returns from altitudes between 40 and 95 km. Analysis of the scale height dependence of the density profiles produced temperatures with a measurement error of about 5 K (∼2.5%) at 90 km when the lidar data was averaged for 20 min. and smoothed in height over 2.7 km. Examination of these profiles for the total of 18 nights showed that there often existed in the mesophere a layer of enhanced temperatures when compared with the U.S. standard profile. The layer centroid height was about 85 km for summer and 70 to 75 km for winter. Data obtained for the equinoctial periods showed the amplitude of these layers to be weak. The winter temperature profiles showed evidence forlong‐period waves passing through the region of the thermal anomaly while the equinox profiles revealed more sporadic wave activity with shorter vertical wavelengths. Both the winter and summer temperature data displayed regions where the observed lapse rate approached the adiabatic lapse rate. In the summer the wave activity near the inversion layer was weak.

Section: Introductionsupporting

confidence: 61%

Rayleigh lidar observations of mesosphere temperature structure

Meriwether¹,

Dao²,

McNutt³

et al. 1994

“…He offered no explanation for this phenomenon but claimed that the feature could not be an artifact of the falling sphere experiment. Examination of rocket and satellite data for southern Spain described by Offermann et al [ 1979] detected anomalous wavelike structure that had horizontal extent as much as 2000 km. Hauchecorne et al [1987] noted the presence of features that consistently appeared in the high-altitude portion of the Rayleigh lidar temperature profiles observed from southern France; these results also indicated that this phenomenon had a broad horizontal breadth of at least 500 km.…”

Section: Properties Of the Mesosphere "Thermal Inversion Layer"mentioning

confidence: 97%

Is chemical heating a major cause of the mesosphere inversion layer?

Meriwether¹,

Mlynczak²

1995

A region of thermal enhancement of the mesosphere has been detected on numerous occasions by in situ measurements, remote sensing from space, and lidar techniques. The source of these “temperature inversion layers” has been attributed in the literature to the dissipation relating to dynamical forcing by gravity wave or tidal activity. However, the conclusion that the dynamics of the mesopause region is the principal source for such anomalies is open to question. While it is certain that the dynamics of gravity wave breaking plays an important role in providing the source of momentum flux required to drive the diabatic circulation, evidence that gravity wave breaking can produce the inversion layer with amplitude as large as that observed in lidar measurements has been limited to results of numerical modeling. We note that an alternative source exists for the production of the thermal inversion layer in the mesosphere, i.e., the direct deposition of heat by exothermic chemical reactions. Two‐dimensional modeling combining a comprehensive model of the mesosphere photochemistry with the dynamical transport of long‐lived species shows that the region from 80 to 95 km may be heated as much as 3 to 10 K/d during the night and half this rate during the day. Given the uncertainties in our understanding of the dynamics and chemistry for the mesopause region, separating the two sources by passive observations of the mesosphere thermal structure looks to be difficult. Therefore we have considered an active means for producing a mesopause thermal layer, namely the release of ozone into the upper mesosphere from a rocket payload. The induced effects would include artificial enhancements of the OH and Na airglow intensities as well as the mesopause thermal structure. The advantage of the rocket release of ozone is that detection of these effects by ground‐based imaging, radar, and lidar systems and comparison of these effects with model predictions would help quantify the partition of the artificial inversion layer production into sources of dynamical and chemical forcing.

“…They are still widely used to study transport and chemistry above the tropopause. However, a zonally averaged picture of the atmosphere cannot describe the large-and small-scale disturbances, and it has been long rocket (GBR) experiments found large and consistent variations in several atmospheric parameters ranging from meters to several kilometers in the vertical direction [e.g., Offermann et al, 1979;Offermann, 1985;Offermann et al, 1987;von Zahn, 1987;Offermann, 1994]. High-altitude aircraft campaigns have also demonstrated the existence of strong, but very small-scale (<100 km) horizontal variations in trace gas mixing ratios [e.g., Bacmeister et al, 1996].…”

Section: Introductionmentioning

confidence: 99%

Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment and middle atmosphere variability

Offermann¹,

Grossmann²,

Barthol³

et al. 1999

Self Cite

195

141

Abstract. The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) instrument was built to determine whether and to what extent small-scale structures in global trace gas distributions and in dynamics are present in the middle atmosphere. To achieve this, trace gases were measured in the middle infrared by the limb scan technique at the highest possible horizontal and vertical resolution. CRISTA uses three telescopes (i.e., three view directions) simultaneously, and has three grating spectrometers for the middle IR (4-14/xm) and one spectrometer for the far IR (15-71 /xm). The optics and detectors are cooled to cryogenic temperatures by supercritical helium or subcooled helium, respectively, in a double cryostat. An instrument overview is given, and the design guidelines are sketched. The CRISTA experiment was flown on the space shuttle STS 66 as part of NASA mission ATLAS 3 on November 3-14, 1994. Orbit altitude was 300 km, and inclination was 57 ø. A campaign of ground-based, balloon, and rocket validation and complementary measurements was performed simultaneously. The CRISTA instrument performed flawlessly. A horizontal resolution of 200 km x 650 km was achieved at the equator, with higher horizontal resolution at higher latitudes. A vertical resolution of 2.5 km (or better) was obtained. The middle atmosphere was found to be highly variable at scales of <1000 km in the stratosphere. Three streamers of tropic/ subtropic air extending to higher latitudes are described. Their meridional scale is -<1000 km, while the zonal scale is of the order of 10,000 km and more. The streamers appear to be typical of specific winter conditions and to play a role in meridional transport. At mesospheric heights a strong tidal temperature oscillation was observed which extended well into the lower thermosphere.