Observations of middle atmospheric H<sub>2</sub>O and O<sub>3</sub> during the 2010 major sudden stratospheric warming by a network of microwave radiometers
- ISSN: 1680-7324
- DOI: 10.5194/acp-12-7753-2012
In this study, we present middle atmospheric water vapor (H2O) and ozone\n(O-3) measurements obtained by ground-based microwave radiometers at\nthree European locations in Bern (47 degrees N), Onsala (57 degrees N)\nand Sodankyla (67 degrees N) during Northern winter 2009/2010. In\nJanuary 2010, a major sudden stratospheric warming (SSW) occurred in the\nNorthern Hemisphere whose signatures are evident in the ground-based\nobservations of H2O and O-3. The observed anomalies in H2O and O-3 are\nmostly explained by the relative location of the polar vortex with\nrespect to the measurement locations. The SSW started on 26 January 2010\nand was most pronounced by the end of January. The zonal mean\ntemperature in the middle stratosphere (10 hPa) increased by\napproximately 25 Kelvin within a few days. The stratospheric vortex\nweakened during the SSW and shifted towards Europe. In the mesosphere,\nthe vortex broke down, which lead to large scale mixing of polar and\nmidlatitudinal air. After the warming, the polar vortex in the\nstratosphere split into two weaker vortices and in the mesosphere, a\nnew, pole-centered vortex formed with maximum wind speed of 70 ms(-1) at\napproximately 40 degrees N. The shift of the stratospheric vortex\ntowards Europe was observed in Bern as an increase in stratospheric H2O\nand a decrease in O-3. The breakdown of the mesospheric vortex during\nthe SSW was observed at Onsala and Sodankyla as a sudden increase in\nmesospheric H2O. The following large-scale descent inside the newly\nformed mesospheric vortex was well captured by the H2O observations in\nSodankyla. In order to combine the H2O observations from the three\ndifferent locations, we applied the trajectory mapping technique on our\nH2O observations to derive synoptic scale maps of the H2O distribution.\nBased on our observations and the 3-D wind field, this method allows\ndetermining the approximate development of the stratospheric and\nmesospheric polar vortex and demonstrates the potential of a network of\nground-based instruments.