Ozone, UV and Aerosol studies

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Current Actions

ES1206: Advanced Global Navigation Satellite Systems tropospheric products for monitoring severe weather events and climate (GNSS4SWEC)

Global Navigation Satellite Systems (GNSS) have revolutionised positioning, navigation, and timing, becoming a common part of our everyday life. Aside from these well-known civilian and commercial applications, GNSS is now an established atmospheric observing system which can accurately sense water vapour, the most abundant greenhouse gas, accounting for 60-70% of atmospheric warming. Severe weather forecasting is challenging, in part due to the high temporal and spatial variation of atmospheric water vapour. Water vapour is under-sampled in the current meteorological and climate observing systems, obtaining and exploiting more high-quality humidity observations is essential to weather forecasting and climate monitoring.

This Action addresses new and improved capabilities from concurrent developments in both the GNSS and meteorological communities. For the first time, the synergy of the three GNSS systems (GPS, GLONASS and Galileo) will be used to develop new, advanced tropospheric products, exploiting the full potential of multi-GNSS water vapour estimates on a wide range of temporal and spatial scales, from real-time monitoring and forecasting of severe weather, to climate research.

In addition the Action will promote the use of meteorological data in GNSS positioning, navigation, and timing services, and it will stimulate knowledge transfer and data sharing throughout Europe.

Three different working groups have been set up to reach these goals:

  • Advanced GNSS processing techniques (WG1)
  • Use of GNSS tropospheric products for high-resolution, rapid-update NWP and severe weather forecasting (WG2)
  • Use of GNSS tropospheric products for climate monitoring (WG3)


The interest of our group clearly lies in the topics discussed in WG3. In particular, R. Van Malderen has been assigned as the leader of the work package WP3.3 "Set up a high quality GNSS Integrated Water Vapour (IWV) dataset" with objectives: (1) to evaluate the uncertainty of GNSS IWV in a comprehensive way and (2) to set up a GNSS IWV dataset suitable for climate applications. R. Van Malderen is also a substitute member of the management committee.

The Action's homepage can be found here, and more information is also available from the Action's webpage on the COST website.


ES1303: Towards operational ground based profiling with ceilometers, doppler lidars and microwave radiometers for improving weather forecasts (TOPROF)

The new generation of high-resolution (1km) weather forecast models now operational over Europe promises to revolutionise predictions of severe weather and poor air quality. To realise this promise, a dense observing network is required, focusing especially on the lowest few km of the atmosphere, so that forecast models have the most realistic state of the atmosphere for initialisation, continuous assimilation and verification. This Action will focus on developing three instruments available throughout Europe:

  • Several hundreds of ceilometers providing backscatter profiles of aerosol and cloud properties with 30m vertical resolution every minute,
  • more than 20 Doppler lidars, a new technology, providing vertical and horizontal winds in the lower atmosphere with a resolution of 30m every 5 minutes, and
  • about 30 microwave profilers giving profiles of temperature and humidity in the lowest few km every 10 minutes.


The aim of the Action is to co-ordinate the operation of these instruments across Europe, so that they can be networked and provide quality controlled and calibrated observations of winds, temperature, humidity, clouds and aerosols in the lowest few km of the atmosphere to National Meteorological and Hydrology Services in near real time. There are four Working Groups in this Action. The first three Working Groups deal with the three instruments: ceilometers (WG1), Doppler lidars (WG2) and microwave radiometers (WG3). The fourth Working Group deals with the use the new data in Numerical Weather Prediction (WG4).

Our team is mostly involved with the activities of WG 1. More specifically, Q. Laffineur has been assigned as the leader of the Task 6 of the WG1 "Use of Automatic LIDAR ceilometers for fog diagnostic and nowcasting" The main objective of the task 6 is to devellop a forward stepwise screening algorithm to help prediction of radiation fog formation and transitions between stratus and fog based on the hydroscopic growth function of aerosol scattering coefficient coupled with the standard surface weather observations. Q. Laffineur is also a member of the Management Committee of TOPROF.

The Action's homepage can be found here, and more information is also available from the Action's webpage on the COST website.