These motions may be used to model the rheology of the Earth's mantle. We may also subtract the land uplift inferred from relative sea level data and search for a possible mean sea level rise. In order to improve the accuracy of the GPS technique work has been concentrated on antenna and site effects. Meteorology Atmospheric water vapor plays an important role in the energy balance of the Earth as one of the most important green-house gases. Furthermore, water vapor is essential in the formation of clouds.
Clouds are important both in climate modeling and for short-term weather predictions.
Measuring the atmospheric water vapor content is, however, difficult with conventional techniques. Investigations on how to use GPS estimated water vapor are currently being carried out by different groups. Using the network of GPS stations in Sweden and Finland we can spatially interpolate the results from the different sites in order to get water vapor maps over the area. This morning an airmass with cooler and therefore dryer air moved over Sweden. This can be seen from the color-coded image, where the red color shows areas with much water vapor and the blue shows areas with less.