We present the implementation of a VLF/LF network to search for earthquake electromagnetic precursors. The proposed system will deliver a steady stream of real-time amplitude and phase measurements as well as a daily recording VLF/LF data set. The first implementation of the system was done in Graz, Austria. The second one will be in Guyancourt (France), with a third one in Réunion (France) and a fourth one in Moratuwa (Sri Lanka).

This paper presents a new dataset of temperature profiles in the upper stratosphere and mesosphere acquired with the GOMOS spectrometer on board the European satellite ENVISAT. The principle is to observe the scattering of sunlight by air molecules at the Earth limb. The observed signal is proportional to the atmospheric density from which the temperature is derived. This technique provides a new source of information on temperature where satellite observations are sparse.

The current study provides intercomparisons of various water vapour measurements in the Arctic. It compares ground-based GPS observations with satellite measurements in the infrared (IR), near-infrared (NIR) and visible (VIS) through a specific method allowing us to quantify their uncertainties and limits. Unlike IR, satellite observations in NIR and VIS bands are mostly sensible to cloud cover during summer and to albedo variability over canopy or polluted snow-covered surfaces in winter.

Understanding water infiltration in karst regions is crucial as the aquifers they host provide drinkable water for a quarter of the world's population. We present a non-invasive tool to image hydrological processes in karst systems. At our field site, the injection of electrical current in the ground, repeated daily over a 3-year period, allowed imaging changes in the groundwater content. We show that specific geological layers control seasonal to rainfall-triggered water infiltration dynamics.