The CoAgMet Network: The CoAgMet Network: Overview, History and How It Overview, History and How It

WorksWorks

Wendy RyanWendy Ryan

Colorado Climate CenterColorado Climate Center

Colorado State UniversityColorado State University

HistoryHistory► In the early 1990’s, CSU extension plant In the early 1990’s, CSU extension plant

pathologists and ARS scientists decided to pathologists and ARS scientists decided to collaborate efforts to collect detail agricultural collaborate efforts to collect detail agricultural weather data.weather data.

► Standard instruments and data collection platform Standard instruments and data collection platform were selected and a small network of stations was were selected and a small network of stations was deployed in fully irrigated agriculture.deployed in fully irrigated agriculture.

► As the network grew, the Colorado Climate Center As the network grew, the Colorado Climate Center became increasingly interested in using the data, became increasingly interested in using the data, began daily data collection, quality control and built began daily data collection, quality control and built a web interface to distribute data and products to a web interface to distribute data and products to users across the state.users across the state.

CoAgMet 1992CoAgMet 1992

CoAgMet 1997CoAgMet 1997

CoAgMet 2002CoAgMet 2002

CoAgMet TodayCoAgMet Today

OverviewOverview

►Currently there are 64 stationsCurrently there are 64 stations►Data are collected on hourly and Data are collected on hourly and

daily time steps and include: daily time steps and include: temperature, humidity, solar temperature, humidity, solar radiation, wind speed and direction, radiation, wind speed and direction, and soil temperatures.and soil temperatures.

►Data and graphics are available Data and graphics are available online: online: ccc.atmos.colostate.edu/~coagmetccc.atmos.colostate.edu/~coagmet

What do the stations What do the stations measure?measure?

Cup anemometer and wind vane: Wind speed, direction and gusts

Pyranometer: Solar radiation

Tipping bucket rain gage

Soil temperatures

Temperature/Humidity sensor in radiation shield

Solar panel powers the station

Data collection platform (DCP)

2 m

2 m

-5/-15 cm

1-3 m

Above all else facing South

Data Collection PlatformData Collection Platform

Datalogger

Power supply

Communications device (cellular modem)

Incoming sensor cables

Why these measurements?Why these measurements?► The main goal of CoAgMet is to calculate The main goal of CoAgMet is to calculate

evapotranspiration (ET) from meteorological evapotranspiration (ET) from meteorological measurements.measurements.

► Several models exist that vary by input data and Several models exist that vary by input data and complexity:complexity: Penman-Monteith – physically basedPenman-Monteith – physically based Kimberly-Penman – physically basedKimberly-Penman – physically based Hargreaves – empirical temperature basedHargreaves – empirical temperature based Standardized ASCE Equation – attempts to standardize Standardized ASCE Equation – attempts to standardize

calculations to make them more comparablecalculations to make them more comparable

► The standard CoAgMet station collects the The standard CoAgMet station collects the elements needed to calculate evapotranspiration.elements needed to calculate evapotranspiration.

Temperature/HumidityTemperature/Humidity

Temperature: During the Temperature: During the growing season, higher growing season, higher temperatures cause the plant temperatures cause the plant stoma to open resulting in stoma to open resulting in greater transpiration.greater transpiration.

Humidity: The higher the Humidity: The higher the humidity the less humidity the less transpiration will occur (more transpiration will occur (more transpiration occurs in dryer transpiration occurs in dryer air)air)

Wind MovementWind Movement

► As air moves across As air moves across plants it will cause plants it will cause more transpiration more transpiration as saturated air as saturated air (from transpiration) (from transpiration) around the plant is around the plant is mixed and dryer air mixed and dryer air can move in.can move in.

Solar RadiationSolar Radiation

► Alfalfa only reflects Alfalfa only reflects about 25% of incoming about 25% of incoming solar energy which solar energy which leaves ample solar leaves ample solar energy to drive ET energy to drive ET rates.rates.

► ET trends follow a ET trends follow a similar pattern as similar pattern as seasonal solar radiation seasonal solar radiation and air temperature.and air temperature.

PrecipitationPrecipitation► While precipitation data While precipitation data

is not explicitly used in is not explicitly used in the ET equations, it the ET equations, it does affect crop does affect crop coefficients used at coefficients used at different locations.different locations.

► Monitoring precipitation Monitoring precipitation also provides an idea of also provides an idea of soil moisture soil moisture availability at the availability at the station.station.

Soil TemperaturesSoil Temperatures

►Having the temperature of the soil aids Having the temperature of the soil aids in knowing when the soil has warmed in knowing when the soil has warmed enough to plant.enough to plant.

►Soil temperature also gives an Soil temperature also gives an indication of the amount of ground indication of the amount of ground cover at the station.cover at the station.

Problems with CoAgMetProblems with CoAgMet

►Missing dataMissing data

►Site exposureSite exposure

►Routine maintenanceRoutine maintenance

Missing/Questionable DataMissing/Questionable Data

►Due to various problems that occur to Due to various problems that occur to remote weather stations, missing data remote weather stations, missing data causes problems for users.causes problems for users.

►Battery failure and communications Battery failure and communications problems are the most common.problems are the most common.

►Even if the whole station doesn’t fail, Even if the whole station doesn’t fail, sensors go bad and can leave some sensors go bad and can leave some elements missing until the station is elements missing until the station is serviced.serviced.

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Peckham, Mean Monthly Wind Run (May-Sept)

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2004 2005 2006 Mean

• Unfortunately, data are not Unfortunately, data are not complete at all stationscomplete at all stations

Missing Data

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Avondale, Mean Monthly Solar Radiation (1992-2006)

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r Pre

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e (m

b)

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Lamar 01, Mean Monthly Vapor Pressure (1998-2006)

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CSU Fruita Experimental Station, Monthly Vapor Pressure (1992-2006)1992

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Mean

Some Data are Questionable

Site ExposureSite Exposure

► One of the assumptions of the One of the assumptions of the evapotranspiration equations is that water is evapotranspiration equations is that water is not limited (i.e. in full irrigation).not limited (i.e. in full irrigation).

► Some stations are not located in ideal Some stations are not located in ideal “reference” conditions.“reference” conditions.

► Some stations have obstructions Some stations have obstructions (buildings/crops) that affect the amount of (buildings/crops) that affect the amount of wind in certain directions.wind in certain directions.

► The exposure of the site can have an impact The exposure of the site can have an impact on the data and over/under estimate on the data and over/under estimate reference ET.reference ET.

Siting and ExposureSiting and Exposure

FTC01 Fort Collins AERC has appropriate citing for reference ET calculations

HOT01 Hotchkiss is not ideally cited for reference ET calculations

The Good… and the Not so Good

Routine MaintenanceRoutine Maintenance

► Due to the fact that CoAgMet is run by Due to the fact that CoAgMet is run by collaborations and operates on a limited collaborations and operates on a limited budget, routine maintenance is difficult with budget, routine maintenance is difficult with such a large network.such a large network. There is no full time CoAgMet technician.There is no full time CoAgMet technician.

► Our goal is to service a station once every 2 Our goal is to service a station once every 2 years.years.

► Data users should be cautious and Data users should be cautious and thoroughly quality control the data they are thoroughly quality control the data they are using.using.

Possible Solutions?Possible Solutions?

►Efforts are being made to fill in missing data Efforts are being made to fill in missing data using relationships with nearby stations.using relationships with nearby stations. This data would be flagged when presented on This data would be flagged when presented on

the website.the website.►Our website now color codes stations Our website now color codes stations

according to their irrigation are classified according to their irrigation are classified as: full irrigation, partial irrigation and as: full irrigation, partial irrigation and dryland.dryland. Making this information available to the public Making this information available to the public

allows them to know more about their data allows them to know more about their data source.source.

Possible Solutions?Possible Solutions?

►We due our best with limited funds to We due our best with limited funds to keep a maintenance schedule but it is keep a maintenance schedule but it is very difficult.very difficult.

► If we are not able to keep high If we are not able to keep high standards for our weather stations, standards for our weather stations, some current stations may need to be some current stations may need to be discontinued in the near future.discontinued in the near future.

► If you value the CoAgMet network, If you value the CoAgMet network, consider donating funds to help consider donating funds to help sponsor a station in your area!sponsor a station in your area!

CoAgMet Website CoAgMet Website DemonstrationDemonstration

The Colorado Climate Center The Colorado Climate Center Home PageHome Page

http://ccc.atmos.colostate.edu/

Hourly Climate Data Hourly Climate Data PlotsPlots

Click Here

Hourly Climate Data Hourly Climate Data PlotsPlots

GLY03 Greely June 9, 2007 through June 15, 2007

Relative Humidity

Temperature

Daily Climatic SummaryDaily Climatic Summary

Click Here

Daily Climatic SummaryDaily Climatic Summary

Monthly Station Monthly Station SummariesSummaries

Click Here

Monthly Station Monthly Station SummariesSummariesKSY01 – Kersey Aug. 2007

Daily Regional Climatic and ET Daily Regional Climatic and ET ComparisonComparison

Click Here

Daily Regional Climatic and ET Daily Regional Climatic and ET ComparisonComparison

North Central Region, May 30, 2007

Crop Specific ET ReportsCrop Specific ET Reports

Click Here

Crop Specific ET ReportsCrop Specific ET Reports

•Calculates multi-day ET for: alfalfa, corn, dry beans, small grain, sugar beets, potatoes, onion, winter wheat, turf grass, and reference ET, via Penman-Monteith or Kimberly-Penman

CoAgMet web access:

http://ccc.atmos.colostate.edu/~coagmet/