water vapor; ozone; climate; microwave radiometry; remote sensing; stratospheric warming
Stähli Oliver, Murk Axel, Kämpfer Niklaus, Mätzler Christian, Eriksson Patrick (2013), Microwave radiometer to retrieve temperature profiles from the surface to the stratopause, in Atmos. Meas. Tech. Discuss.
, 6, 2857-2905.
Scheiben Dominik, Schanz Ansgar, Tschanz Brigitte, Kämpfer Niklaus (2013), Diurnal variations in middle atmospheric water vapor by ground-based microwave radiometry, in Atmos. Chem. Phys. Discuss.
, 13, 3859-3880.
Tschanz Brigitte, Straub Corinne, Scheiben Dominik, Walker Kaley A., Stiller Gabriele, Kämpfer Niklaus (2013), Validation of middle atmospheric campaign-based water vapour measured by the ground-based microwave radiometer MIAWARA-C, in Atmos. Chem. Phys. Discuss.
, 6, 1311-1359.
Rüfenacht Rolf, Kämpfer Niklaus, Murk Axel (2012), First middle-atmospheric zonal wind profile measurements with a new ground-based microwave Doppler-spectro-radiometer, in Atmospheric Measurement Techniques
, 5(11), 2647-2659.
Scheiben Dominik, Straub Corinne, Hocke Klemens, Forkman Peter, Kämpfer Niklaus (2012), Middle atmospheric water vapor and ozone anomalies during the 2010 major sudden stratospheric warming, in Atmos. Chem. Phys. Discuss.
, 11, 32391-32422.
Scheiben Dominik, Straub Corinne, Hocke Klemens, Forkman Peter, Kämpfer Niklaus (2012), Observations of middle atmospheric H2O and O3 during the 2010 major sudden stratospheric warming by a network of microwave radiometers, in Atmos. Chem. Phys.
, 12, 7753-7765.
Straub Corinne, Tschanz Brigitte, Hocke Klemens, Kämpfer Niklaus, Smith Anne K. (2012), Transport of mesospheric H2O during and after the stratospheric sudden warming of January 2010: observation and simulation, in Atmos. Chem. Phys. Discuss.
, 11, 32811-32846.
Stiller G. P., Kiefer M., Eckert E., von Clarmann T., Kellmann S., Garcia-Comas M., Funke B., Leblanc T., Fetzer E., Froidevaux L., Gomez M., Hall E., Hurst D., Jordan A., Kämpfer N., Lambert A., McDermid I. S., McGee T., Miloshevich L., Nedoluha G., Read W., Schneider M., Schwartz M., Straub C., Toon G. (2012), Validation of MIPAS IMK/IAA temperature, water vapor, and ozone profiles with MOHAVE-2009 campaign measurements, in Atmos. Meas. Tech.
, 5, 289-320.
Leblanc T., Walsh T. D., McDermid I. S., Toon G. C., Blavier J.-F., Haines B., Read W. G., Herman B., Fetzer E., Sander S., Pongetti T., Whiteman D. N., McGee T. G., Twigg L., Sumnicht G., Venable D., Calhoun M., Dirisu A., Hurst D., Jordan A., Hall E., Miloshevich L., Vömel H., Straub C., Kämpfer N. (2011), Measurements of Humidity in the Atmosphere and Validation Experiments (MOHAVE)-2009: overview of campaign operations and results, in Atmos. Meas. Tech.
, 4, 2579-2605.
Straub Corinne, Murk Axel, Kämpfer Niklaus, Golchert Sven H. W., Hochschild Gerd, Hallgren Kristofer, Hartogh Paul (2011), ARIS-Campaign: Intercomparison of three ground based 22GHz radiometers for middle atmospheric water vapor at the Zugspitze in winter 2009, in Atmos. Meas. Tech.
, 4, 1979-1994.
Stähli Oliver, Mätzler Christian, Murk Axel, Kämpfer Niklaus (2011), A Surface-Based Imaging Method for Water Vapor and Liquid Clouds Using a Scanning Radiometer at 91 GHz, in IEEE Transaction on Geoscience and Remote Sensing
, 49(9), 3273-3280.
Wachter Evelyn De, Hocke Klemens, Flury Thomas, Scheiben Dominik, Kämpfer Niklaus, Ka Soohyun, Oh Jung Jin (2011), Signatures of the Sudden Stratospheric Warming events of January - February 2008 in Seoul, S. Korea, in Advances in Space Research
, 48, 1631-1637.
To obtain a reliable global picture of the changing atmosphere, a coupled observational / modeling system is required. Such a system must include a network of ground-based instrumentation of different techniques including balloon sondes, millimeter wave radiometers, lidar etc. to measure relevant parameters such as stratospheric water vapor and ozone. Water vapor, cloud liquid and water in the form of ice particles play many roles in atmospheric physics and - more generally - in earth sciences. In the troposphere water vapor is the most important greenhouse gas, in the middle atmosphere it contributes significantly to cooling processes and to ozone chemistry. Due to its long chemical lifetime it can also be used as a tracer to study dynamical processes in the atmosphere. However despite the multiple and important roles water plays in atmospheric physics and chemistry information about its distribution up to the mesosphere is limited. There are a few satellite sensors to provide the altitude distribution of water vapor. They are limited in their temporal or spatial coverage and in addition they suffer from a limited lifetime that makes it very difficult to assess any trends. Furthermore satellite sensors may suffer from degradation and thus need validation by ground truth instruments. Such validation can be provided by ground-based remote sensing instruments with high quality as operated within the Network for the Detection of Atmospheric Composition Change, NDACC. The Institute of Applied Physics (IAP) at Bern together with the observatory at Zimmerwald acts as one of the primary stations of NDACC and contributes with two microwave radiometers, one for ozone and the other one for water vapor. The ozone data series obtained with the radiometer GROMOS extends by now to more than 15 years with an unprecedented time resolution of a few minutes. The analysis of atmospheric phenomena at time scales from annual to as low as minutes is exceptional. With the middle atmospheric water vapor radiometer, MIAWARA, we dispose over a most successful instrument that can retrieve water vapor in the middle atmosphere. In collaboration with MeteoSwiss and their balloon soundings we aim at retrieving the water vapor distribution from the ground to the upper mesosphere. Our research contributes to the Swiss part of the Global Climate Observing System, GCOS, and of the Global Atmospheric Watch program, GAW, of the World Meteorological Organization, WMO.The scientific objectives of this research project are aimed at understanding the significance of the variability in atmospheric H2O at mid-latitudes over different time scales and to investigate the links between ozone and water vapor. A special aspect will be devoted to sudden stratospheric warmings and their effect on ozone and water vapor and relation to dynamical phenomena in the middle atmosphere. An important aspect is the participation in measurement campaigns in the tropics and in the arctic where ground based measurements of water vapor are almost inexistent. Further insight into the atmospheric processes shall be obtained by combining our data with atmospheric models in cooperation with other research teams.The main objective of our research is the investigation of:1.temporal variability of water vapor in the middle atmosphere (stratosphere and mesosphere) and its interaction and relation with ozone2.humidity in the form of vapor and liquid and if possible also ice in the troposphere together with related parameters (such as temperature, cloud altitude, etc). Temporal variability can span a wide branch of time scales from trend effects over decades, to links with the solar cycle, to annual and other periodic phenomena like QBO (Quasi Biannual Oscillation), semi-annual oscillations etc. But also short-duration phenomena such as abrupt changes of the atmospheric circulation that may happen during so called sudden stratospheric warmings (SSW) and linked to it, mesospheric coolings, and their effect on the amount of H2O and O3 shall be investigated. For such analysis we will use data obtained from our own instruments where they are unique and outstanding and complement them with data from other instruments particularly from satellites. In order to understand relevant processes responsible for such variability atmospheric models shall be used. All the proposed work would not be possible without a significant collaboration with external international partners as successfully done in previous years.