The relation between space geodetic measurements and atmospheric models is twofold: (1) the geodetic measurements can be evaluated to derive parameters of physical, empirical or analytical atmospheric models and (2) models are used to correct the electromagnetic signals for the atmospheric effects. In other words ionospheric and tropospheric signals like the vertical total electron content and the zenith total delay are either the target functions or interpreted as disturbing signals.

Space geodetic techniques such as GNSS (ground- and LEO-based), VLBI, satellite altimetry or the GPS radio occultation missions (CHAMP/GRACE, Formosat-3/COSMIC, TerraSAR-X, OCEANSAT2) can provide valuable information about the lower neutral atmosphere (troposphere and stratosphere) and the ionosphere. The potential for atmospheric sensing using these techniques has improved considerably over the last few years as a result of technological advances, larger ground networks and developments of appropriate models and algorithms. Accurate atmospheric estimates and retrievals based on these techniques may significantly improve our understanding on the physical and dynamic characteristics of weather and climate as well as space weather at various scales. Consequently, contributions on physical modeling of the neutral atmosphere and the ionosphere are highly appreciated. Recent sounding results, report on achieved improvements of the accuracy and of the spatio-temporal resolution of derived tropospheric, stratospheric and ionospheric parameters as well as theoretical studies that assess requirements for the accuracy of relevant parameters are also welcome.

Positioning via receivers recording signals from GNSS plays an ever increasing role, both for ordinary citizens and for specialised high precision work. For instance, the forthcoming civilian European GALILEO system will provide new application fields, for which the atmospheric disturbances have to be considered properly in the overall error budget for the navigation solution. Contributions to discuss ionospheric and neutral atmospheric effects on the GNSS signals and on other techniques at radio wavelengths, such as VLBI and spacecraft ranging, as well as current techniques to perform neutral atmosphere media calibration and model forecast are encouraged. Studies on how to mitigate such effects for improving GNSS positioning, navigation and observations at radio wavelengths are highly appreciated. In addition we solicit contributions to empirical or numerical correction models, user services and receiver technology to handle atmospheric corrections.