Monday, 7 January 2013
Exhibit Hall 3 (Austin Convention Center)
We tried to produce the climatological propagation of atmospheric phenomena such as migration of low pressure system, expansion of high pressure system, etc. In this study, we utilized the lag correlation technics. First, select target grid point and calculate one-point +1 time unit (a day) and -1 time unit lag correlation map for certain time duration. Then, we can define the atmospheric propagation vector (AMV) as displacement of closest positive center between the -1 lag correlation map and +1 lag correlation map. The atmospheric propagation vector (AMV) is consist of magnitude (or velocity), direction and averaged correlation coefficient between two lag correlation maps. If we apply above AMV technics to daily 500-hPa geopotential field, some features shown: eastward slow propagation over high-latitude, westward fast propagation over equator region. In addition, we conducted AMV technics to two different variables. AMV between 1000-hPa temperature and 1000-hPa geopotential height looks weird and spurious. AMVs sourced from Africa and Pacific equator region and sunk into polar region. This feature partly differs from AMV between 500-hPa temperature and geopotential height. On 500-hPa, 1000-hPa feature is only shown over equator region and eastward AMV over high-latitude appears. Because understanding of AMV is difficult and controversial, more works are needed: AMV of idealized phenomena, AMV of different reanalysis datasets, AMV of filtered datasets, and so on.
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