Browsing by Author "Englert, Christoph R."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Polar mesospheric cloud mass and the ice budget: 2. Application to satellite data setsStevens, Michael H.; Englert, Christoph R.; DeLand, Matthew T.; Bailey, Scott M. (American Geophysical Union, 2007-04-01)[ 1] We use satellite observations of mid-UV solar backscattered light from polar mesospheric clouds (PMCs) to constrain the water ice budget. We compare the PMC mass from observations by two instruments: the limb viewing Student Nitric Oxide Explorer (SNOE) and the nadir viewing Solar Backscattered UltraViolet (SBUV) experiments. At 70 +/- 2.5 degrees N we find that SNOE measures over three times more PMC mass than the less sensitive SBUV experiment. We directly compare the two data sets by selecting only the brightest 10% of SNOE clouds so that the SNOE and SBUV PMC occurrence frequencies are the same. This comparison shows that the PMC mass averaged over five northern seasons is the same to within uncertainties in the ice particle size distribution. We also find that near midday, the northern SBUV PMC mass is a factor of 2.4 times greater than the southern PMC mass. These results provide new constraints for global climate models of PMC formation.
- Vertical Shears of Horizontal Winds in the Lower Thermosphere Observed by ICONEngland, Scott L.; Englert, Christoph R.; Harding, Brian J.; Triplett, Colin C.; Marr, Kenneth; Harlander, John M.; Swenson, Gary R.; Maute, Astrid; Immel, Thomas J. (American Geophysical Union, 2022-06-16)Vertical shears of horizontal winds play an important role in the dynamics of the upper atmosphere. Prior observations have indicated that these shears predominantly occur in the lower thermosphere. MIGHTI observations from the Ionospheric Connection Explorer indicate that strong wind shears are a common feature of the lower thermosphere between 100-130 km, varying greatly between orbits. This work focuses on these strong shears, and examines their occurrences, horizontal scales and underlying organization. The wind shears can persist for 1000s km horizontally. Over a large data set, no preferred direction for the strong wind shears is found. The shears that persist for a short horizontal extent are slightly larger in amplitude and more numerous than those that persist across large horizontal scales. The altitude at which the strongest shears occur, regardless of the horizontal extent, show a downward progression with local time, following the climatological winds and upward propagating tides.