ESRL Global Systems Division

The Cooperative Agency Profiler (CAP) network reaches 90 profilers

The CAP network started in 1996. Forty agencies and 90 profilers later it is truly bridging profiler resources between research and operations, and between different meteorological disciplines. This network consists of profilers operated by independent cooperative agencies who share existing national and international profiler resources to help improve weather forecasts and numerical model outputs, thus helping to save lives, reduce injuries, save property and promote economic gain. These agencies include five NOAA groups, including four OAR laboratories: Forecast Systems Laboratory (FSL), Environmental Technology Laboratory (ETL), Aeronomy Laboratory (AL), and Air Resources Laboratory (ARL). There are also eleven other federal agencies, five universities (one in Canada), thirteen other state agencies, one private company, and five foreign agencies (including Canada, Japan, Hong Kong, Germany, and Peru). FSL's NOAA Profiler Network (NPN), a separate network of 35 tropospheric profilers, laid the groundwork and provides the infrastructure for the CAP network.

A profiler is an all-weather, unmanned, vertically pointing, clear-air Doppler radar. This cost effective instrument excels at detailed measurements of a vertical profile of the wind field at a high temporal resolution. These measurements include horizontal motion (U and V), vertical motion (W), humidity and temperature gradients, and precipitation fall velocity. The level of detail depends on the configuration and type of profiler. The vertical distance between measurements varies from 60 to 300m in the lower atmosphere and 100 to 1000m in the upper troposphere to the lower stratosphere. The temporal frequency varies from 5 to 60 minutes. The maximum height coverage varies from 3 to 22km. The number of wind points measured per hour varies between 40 and 700+. The profiler can also measure temperature profiles in the lower atmosphere if equipped with a Radio Acoustic Sounding System.

Leveraging the NPN program to build the CAP network has proven very successful. The NPN program has a solid record of providing reliable profiler data to NWS forecasters and the National Centers for Environmental Prediction (NCEP) models for over 10 years. This same infrastructure supports the CAP network. A testimony of the success of this partnership is the 500+ NWS Area Forecast Discussions (AFD) that referenced CAP and NPN profilers between January 13 and April 30, 2003.

The CAP data are used for forecasting and model input for severe and significant weather cases. Severe weather cases include tornadoes, hail, flooding, snowstorms, ice storms, heavy rains, and high winds. Significant weather cases involve weather effects on air quality, forest fires, aviation, dispersion incidents, diurnal wind and temperature cycles, and temperature forecasts. The data are also used to validate and assess operational numerical model outputs. Upwind profilers allow earlier model output assessment, thereby improving lead time for many events. CAP measurements are used in real time by many agencies including the National Weather Service (NWS), National Ocean Service (NOS), Environmental Protection Agency (EPA), Department of Defense (DOD), Department of Energy (DOE), Federal Aviation Administration (FAA), and the National Center for April 12, 2006 the data are used for post analysis of weather events to assist the development of new numerical models and analysis techniques. The detail in the CAP data is the reason they are used. It shows light and variable winds and boundary layer depth for dispersion and air quality forecasts. It shows high winds, shear, and vertical motion for severe weather forecasts. It shows significant changes in the wind field for small and large scale events in both height and time. This level of detail makes it a great complement to other upper-air data sources.

This network is truly a cooperative effort. Every agency involved has contributed hardware resources and profiler expertise in both operations and applications knowledge. ETL has worked closely with FSL on the project. ETL's expertise with boundary layer profilers is a critical element. AL, ETL, ARL, NWS, DOE, and EPA have provided input on severe weather, air quality, climate, and dispersion issues. ETL and DOD have provided assistance with data quality control algorithms.

Displays of real-time CAP data are available on properly configured NWS workstations. Real-time and historical data are also available on FSL's web page. The data are on NOAAPort and the Global Communications System (GTS). For more information, please contact: Doug van de Kamp (303-497-6309; or Leon Benjamin (303-497-6031;

Contact information
Name: Leon Benjamin
Tel: 303-497-6031