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Programmes > GAW > Observations > Measurements > Contributing networks

Networks contributing to the GAW Programme (Contributing networks)


A contributing network is one that has signed a letter of agreement (LoA) with WMO. Any such agreement should contain a list and the characteristics of the stations that will be included in the GAW network as Contributing stations. List of stations that are contributing to the GAW Programme is given after the short network descriptions.

GAW Contributing networks:


The Total Carbon Column Observing Network (TCCON; and is a ground-based network of high resolution Fourier transform spectrometers (FTSs) that records the near infrared solar absorption spectrum and retrieves column-average mixing ratios of CO2, CH4, N2O and several other gases with high precision and accuracy.  TCCON data are a valuable complement to in-situ surface data and can be included in global inversions and other models of greenhouse gases, including studies of the carbon and nitrogen cycles.  Furthermore, the column measurements serve to validate satellite measurements from the current satellites GOSAT and SCIAMACHY and future satellite missions such as OCO-2. 

List of stations


The European Aerosol Research Lidar Network (EARLINET; is European coordinated lidar network, established in 2000, measuring aerosol backscatter coefficient and aerosol extinction profiles for climatological studies of the aerosol distribution over Europe.

List of stations


The Interagency Monitoring of Protected Visual Environments (IMPROVE) program is a cooperative measurement effort governed by a steering committee composed of representatives from Federal and regional-state organizations ( IMPROVE-Optical monitoring network uses open air nephelometers to measure hourly particulate scattering in primarily rural environments.  In addition, hourly temperature and relative humidity are measured at each site.  These data are used in conjunction with IMPROVE aerosol data to assess the status and trends in light scattering and better understand the optical properties of aerosols.

List of stations


The Asian Dust and Aerosol Lidar Observation Network (AD-Net: is an Asian coordinated lidar network, established in 2001, measuring aerosol backscattering and the depolarization for Asian dust and performing regional air pollution studies over East Asia.

List of stations


The Latin America Lidar Network - ALINE (the current provisional address will be replaced with some time in 2013) is a Latin American coordinated lidar network.  ALINE was established in 2008, measuring aerosol backscatter coefficient and aerosol extinction profiles over Latin America.

List of stations


The U.S.-based National Atmospheric Deposition Program (NADP) is a long-term, measurement cooperative composed of representatives from federal, state, tribal, and national agencies, universities, private companies, and non-governmental organizations. Most NADP stations are located in the United States but several are located in Canada and in other nations. NADP operates three precipitation chemistry networks: the National Trends Network (NTN), the Atmospheric Integrated Research Monitoring Network (AIRMoN); and the Mercury Deposition Network (MDN), and two gaseous atmospheric chemistry networks: the Atmospheric Mercury Network (AMNet) and the Ammonia Monitoring Network (AMoN). A central office coordinates Program activities and oversees field and lab operations, data management, and quality assurance for each network.  Each monitoring network follows well-defined protocols to measure acidic compounds, nutrients, base cations, and mercury in precipitation (NTN, AIRMoN, and MDN), and ambient concentrations of ammonia and mercury for estimates of dry deposition (AMoN and AMNet).  Program data are used to assess the geographic patterns and long-term temporal trends in the concentration and deposition of major ions and mercury in precipitation, and to better understand the cycling of these chemicals in a variety of physical environments for a multitude of applications.





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