Meteorology

NEON installs on-bank/riparian met stations, above water met stations, and met/flux towers to collect meteorological data.

Weather and climate conditions along with seasonally changing biological and biogeochemical processes are important drivers and indicators of terrestrial and aquatic ecosystem function. To better understand these processes, NEON deploys automated sensors to collect meteorological data at both aquatic and terrestrial sites. These sensors are part of NEON's Automated Instruments system. Data are collected continuously to capture patterns and cycles across various time periods, ranging from seconds to years. NEON calibrates and quality checks sensors to minimize measurement errors and maximize the quality of collected data.


Types of Instrument Infrastructure by Field Site


 Streams

Rivers

Lakes

Terrestrial Sites

Precipitation Gauge

Precipitation Gauge

Precipitation Gauge

Precipitation Gauge

Riparian Met Station

Riparian Met Station

Riparian Met Station

Met/Flux Tower

 

Above-Water Met Station

Above-Water Met Station

Soil Array

Riparian Met Stations

At each aquatic field site, one meteorological station (or met station) is installed on the bank of the aquatic body, in the riparian area, to collect weather and climate data. The met station is ~3 m tall and configured with a subset of the meteorological sensors deployed on NEON’s terrestrial flux towers. These measurements include:

  • Wind speed and direction
  • Air temperature
  • Barometric pressure
  • Relative humidity
  • Shortwave radiation
  • Photosynthetically active radiation (PAR)

Please note these data are categorized as TIS (Terrestrial Instrument System) data on the NEON data portal. Sensor-specific details can be found in the data product documentation on the NEON data portal.

Above-Water Met Stations

At lake and river sites, above water conditions can be different from riparian conditions due to the increased width of open water which results in increases in light exposure and decreased shading from riparian vegetation. Turbulence also naturally decreases with stream order. As a result, wind speed and barometric pressure begin to dominate gas exchange at the water surface in larger rivers. NEON installs an above-water met station at lake and river sites to collect the same data listed above. The above-water met station is also placed in close proximity to in situ surface water sensors and where grab samples are collected for biogeochemical measurements. Due to power and communication limitations, buoy data are collected less frequently than riparian met station data.

  • At lake sites, the above-water met station is mounted on a buoy outfitted with aquatic sensors and placed near the deepest location of the main basin.
  • At river sites, the above-water, buoy-mounted met station is placed near the thalweg, but outside of the main navigational channel.

Please note these data are categorized as AIS (Aquatic Instrument System) data on the NEON data portal.

Met/Flux Towers

Heat, water vapor, carbon dioxide and other gases are continually exchanged between the earth’s surface and the atmosphere. Soil, vegetation and other living things on the earth absorb energy from the sun and take in gases and water from the atmosphere, directly or through precipitation. They also radiate heat, send water back into the atmosphere through evapotranspiration, and release carbon and other gases back into the air through respiration. In a very real way, we can think of these fluxes as the planet breathing. To monitor this exchange at the boundary layer between living and nonliving things on the earth and the atmosphere above, NEON collects eddy covariance in addition to weather and climate data at each terrestrial field site.

Data are collected using a series of automated sensors installed on a meteorological tower. This flux tower is placed in the dominant vegetation of the field site and positioned to maximize data capture along the predominant wind direction in order to measure the representative ecosystem.

The flux tower typically extends past the top of the vegetation canopy to allow sensors mounted at the top and along the tower to capture a full vertical profile of atmospheric conditions from the top of the vegetation canopy to the ground. The number of measurement levels on a tower vary from four to eight levels depending on the ecosystem structure at each site. Each boom arm is 4 m long, which is double the width of the tower to minimize the impact of flow distortion caused by the tower on wind measurements.

The micrometeorological data collected by NEON flux towers yield over 19 eddy covariance data products. These data are collected using sensors that measure temperature, moisture and gas concentrations within the turbulent air currents that move past a flux tower. By combining these data with information about the speed and direction of the air currents themselves, we can get a picture of how energy, water and gases are flowing into and out of the atmospheric boundary layer. There are several other networks already collecting comparable flux data in the U.S. and internationally, including AmeriFlux, FLUXNET, and ICOS. NEON greatly expands the number of geographic areas and types of ecosystems where these data are being collected. NEON also samples wet deposition and dust particulate at select sites.

The tower airshed (or tower footprint) includes soil sensor plots and tower observational sampling plots to allow direct integration with and extrapolation between types of measurements. For example, meteorological measurements combined with NEON’s soil, plant and organismal data support the ecosystem-level study of carbon dioxide, water vapor and energy fluxes, as they cycle through the atmosphere, vegetation and the soil. Tower data combined with soil and airborne remote sensing data supports scaling of fluxes, soil moisture and evapotranspiration to a continental scale

Sensor-specific details can be found in the data product documentation on the NEON data portal.

Meteorological Measurements Taken at Soil Plots

Near the flux tower at each terrestrial field site, NEON installs a soil array of five soil plots. Each plot is outfitted with above ground meteorological sensors and a series of soil sensors that collect data at multiple depths in the ground. Meteorological data include:

  • Precipitation (via throughfalls)
  • Net-longwave radiation
  • PAR - quantum line
  • IR biological temperature
  • Relative humidity
  • Soil heat flux

Sensor-specific details can be found in the data product documentation on the NEON data portal.

Precipitation Gauges

Precipitation data are collected in a variety of ways at terrestrial and aquatic sites. If aquatic and terrestrial sites are co-located, e.g. within 10 km of each other and in the same watershed, precipitation data are collected primarily at the terrestrial site. If an aquatic site is further than 10 km from a NEON terrestrial site, in a different watershed, or in area with different climatic conditions within the same watershed, NEON collects additional precipitation data at the aquatic site.

Precipitation Data Collection Types

  • Double Fence Intercomparison Reference (DFIR): These are used as NEON’s primary precipitation collector. DFIRs are installed within the an open area unencumbered by high vegetation. DFIRs are set up at NEON’s twenty core terrestrial field sites and four additional aquatic sites.
  • Tipping Bucket: These are located at the top of the flux tower at NEON’s 27 relocatable terrestrial sites. A tipping bucket collecting secondary precipitation is also installed at eight core terrestrial sites that have higher vegetation canopies or where the DFIR is placed quite far from the tower. Six aquatic sites are outfitted with tipping buckets at the top of the met station.
  • Throughfall: These are installed in the soil array at most terrestrial field sites. Sites that have an average vegetation canopy height of 3 m or less may not have throughfalls.

Sensor-specific details can be found in the data product documentation on the NEON data portal.

Meteorological Data Collection Across Site Types

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Additional Automated Instrument Measurements

NEON also uses automated instruments to collect phenology, soil, surface water, and groundwater data.

Meteorological Data Products

  • Photosynthetically active radiation (PAR)
  • Photosynthetically active radiation (quantum line)
  • Shortwave and longwave radiation (net radiometer)
  • Shortwave radiation (direct and diffuse pyranometer)
  • Shortwave radiation (primary pyranometer)
  • Spectral sun photometer - calibrated sky radiances
  • Particulate mass
  • Dust and particulate size distribution
  • Barometric pressure
  • Relative humidity
  • Triple aspirated air temperature
  • Single aspirated air temperature
  • IR biological temperature
  • Precipitation
  • Soil flux plate
  • Stable isotope concentrations in precipitation
  • Wet deposition chemical analysis
  • 2D wind speed and direction
  • Temporally interpolated PAR-line
  • Temporally interpolated photosynthetically active radiation
  • Temporally interpolated shortwave and longwave radiation
  • (net radiometer)
  • Temporally interpolated triple aspirated tower temperature
  • Temporally interpolated biological temperature
  • Bundled data products - eddy covariance
    • 3D wind attitude and motion reference
    • 3D wind speed, direction and sonic temperature
    • Atmospheric CO2 isotopes
    • Atmospheric H2O isotopes
    • Carbon dioxide flux
    • CO2 concentration - storage
    • CO2 concentration - turbulent
    • CO2 concentration rate of change
    • CO2 concentration rate of change profile
    • Flux footprint characteristics
    • H2O concentration - storage
    • H2O concentration - turbulent
    • H2O concentration rate of change
    • H2O concentration rate of change profile
    • Latent heat flux
    • Momentum flux
    • Sensible heat flux
    • Temperature rate of change
    • Temperature rate of change profile
  • Summary weather statistics

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