Rayleigh Lidar Observations of the Mid-Latitude Mesosphere During Stratospheric Warming Events and a New Rayleigh-Mie-Raman Lidar at USU
| Autor: | Sox, Leda, Wickwar, Vincent B., Fish, Chad, Herron, Joshua P., Emerick, Matthew T. |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Presentations Leda Sox |
| Popis: | The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), collected temperature data for 11 years, from 1993 through 2004. The temperatures derived from these data extended over the mesosphere, from 45 to 90 km. Recently, these temperatures were combined with other observations to examine the mid-latitude response to Sudden Stratospheric Warmings (SSWs) in the polar regions. Extensive Rayleigh lidar observations were made during a several SSW events. In order to look for effects of the SSWs, comparisons were made between the temperature profile on individual nights during an SSW event and the climatological temperature profile for that night of the year. An overall disturbance pattern was observed in the mesospheric temperatures during northern hemisphere SSWs. It included coolings (sometimes very significant) in the upper mesosphere and warmings in the lower mesosphere, which were often related to increases in the stratopause altitude. Currently, the ALO Rayleigh lidar system is going through a series of upgrades to transform it to a Rayleigh-Mie-Raman (RMR) scatter lidar. The scientific impetus for these upgrades is to extend the observing range both higher and lower in altitude. This will be achieved by increasing the sensitivity by 70 times, which will make this the most sensitive lidar, of its type, in the world. This will allow measurements to be made of relative densities and absolute temperatures throughout most of the stratosphere, mesosphere and lower thermosphere, from approximately 15 to 120 km. After the upgrade, the intent, as with the original Rayleigh lidar, is to observe as often as possible. This will provide an extensive data set for many types of analyses. Initially, it will provide good information about the poorly observed region between 90 and 120 km. Later, by normalizing the relative lidar densities to absolute densities in a reanalysis model or to observed radiosonde densities below 30 km, an absolute density profile will be obtained for the first time up to 120 km. There are many scientific applications that will benefit from the extended range of the new RMR lidar. For instance, new observations could extend the description of SSW occurrences from the stratosphere and mesosphere into the lower thermosphere, observed thermospheric densities could be provided for the models used to evaluate satellite drag, especially during major space weather events, and the effects of weather events in the lower atmosphere could be traced all the way to the thermosphere. Already, we have found significant temperature differences between observed temperatures and those from the MSISe00 empirical model. |
| Databáze: | OpenAIRE |
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