National Atmospheric Deposition Program (NADP)

Linking transit times to catchment sensitivity in western U.S.

Linking transit times to catchment sensitivity in western U.S.

Short transit times—the time between entry of a water molecule into the ground surface and when it exits the catchment—is a key reason why western U.S. high-elevation catchments are highly sensitive to atmospheric pollution and climate change.

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Long-term changes in soil and stream chemistry in northeastern U.S.

Long-term changes in soil and stream chemistry in northeastern U.S.

Accelerating reductions in acidic deposition have led to improvements in many streams but not for soils, reports a USGS study. Recovery of soils has likely been limited by decades of acid deposition.

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The National Atmospheric Deposition Program (NADP) monitors precipitation chemistry through five monitoring networks. USGS supports monitoring sites within the National Trends Network and the Mercury Deposition Network.

National Atmospheric Deposition Program

National Trends Network (NTN)

NTN Site Map

Mercury Deposition Network (MDN)

MDN Site Map

Science Center Objects

The National Atmospheric Deposition Program (NADP) is a multi-partner atmospheric monitoring program that measures the concentrations and deposition of atmospheric constituents across North America. The USGS has been an NADP partner agency since 1981 and participates by providing funds for 82 National Trend Network (NTN) sites.

The National Atmospheric Deposition Program (NADP) operates five monitoring networks for various constituents of which the National Trends Network (NTN) is the largest with 263 sites where the major ions in precipitation are measured weekly. The U.S. Geological Survey (USGS) has been an NADP partner agency since 1981 and participates by providing funds for 82 NTN sites. 

► More about the NADP data, program, and networks

Data from the NADP networks are used to track trends and examine spatial patterns in atmospheric deposition of constituents that include nitrogen, sulfur, mercury, calcium, and others. Many of these constituents are naturally present in the atmosphere but also originate in part as air pollutant emissions from human activities such as from power plants and vehicles. Clean air policies implemented under the Clean Air Act, as part of global treaties, and by other regulations typically set targets for reducing emissions, which are tracked by NADP measurements. In this manner, there is a close link between science, policy, and management among NADP partners. The identical field sampling protocols and equipment and analyses by one laboratory using the same methods facilitates comparisons across sites and highlights the value of a multi-partner monitoring program.

 

Annual gradient maps

The NADP creates annual gradient maps of precipitation-weighted mean concentrations and depostion for NTN.  Maps for each year from 2018 to 1985 are available for several different parameters.

Slider maps showing the difference in concentrations and deposition for pH, sulfate, and nitrogen are below.  The left image shows the 2018 map and the right image shows the 1985 map.  You can use the slider to compare the two views side by side, or click the 'show only left' or 'show only right' links under each slider to view the 2018 or 1985 map in full.

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Hydrogen ion concentration as pH, National Atmospheric Deposition Program/National Trends Network, 1985 and 2018.

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Sulfate ion wet deposition, National Atmospheric Deposition Program/National Trends Network, 1985 and 2018.

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Inorganic nitrogen wet deposition, National Atmospheric Deposition Program/National Trends Network, from 1985 and 2018.