The CoAgMet Network: Overview History and How It Overview, Works N l Doesken Nolan D k and d Wendy W d Ryan R Colorado Climate Center Colorado State University
First -- A short background In 1973 the federal government abolished the State Climatologist program nationwide leaving Colorado without Later that same year, Colorado re-established established the State Climate program with support through the Colorado Agricultural Experiment Station at Colorado State University.
Our Mission The Colorado Climate Center at CSU provides valuable climate expertise to the residents of the state through its threefold program of: 1) Climate Monitoring (data acquisition, analysis, and archiving), 2) Climate Research 3) Climate Services.(providing data, analysis, climate education and outreach)
Monitoring our Climate Elements: temperature, precipitation, snow, wind, solar, evaporation, soil temperatures, humidity, clouds, etc. Fort Collins CSU Historic Weather Station Continuous monitoring since the 1880s
Vail Mountain Snotel
Montrose Annual Precipitation (1899 2011)
CoAgMet = Colorado Agricultural Meteorological Network
History of CoAgMet In the early 1990 s, CSU extension plant pathologists and USDA Ag. Research Service scientists decided to collaborate efforts to collect agricultural weather data. Standard automated instruments and data collection platforms were selected and a small network of stations was deployed in fully irrigated agriculture. As the network grew, the Colorado Climate Center became increasingly interested in using the data, began daily data collection, quality control and built a web interface to distribute data and products to users across the state.
CoAgMet 1992
CoAgMet 1997
CoAgMet 2002
CoAgMet Today
Overview Currently there are 65 stations Data are collected on hourly and daily time steps and include: temperature, humidity, solar radiation, wind speed and direction, and soil temperatures. Data and graphics are available online: ccc.atmos.colostate.edu/~coagmet t t coagmet
What do the stations measure?
Cup anemometer and wind vane: Wind speed, direction and gusts 2 m Above all else facing South Pyranometer: Solar radiation Temperature/Humidity sensor in radiation shield Solar panel powers the station 2 m 1-3 m Tipping bucket rain gage Data collection platform (DCP) -5/-15 cm Soil temperatures
Data Collection Platform Power supply Datalogger Communications device (cellular modem) Incoming sensor cables
Why these measurements? The main goal of CoAgMet is to calculate evapotranspiration (ET) from meteorological measurements. Several models exist that vary by input data and complexity: Penman-Monteith physically based Kimberly-Penman physically based Hargreaves empirical temperature based Standardized ASCE Equation attempts to standardize calculations to make them more comparable The standard d CoAgMet station collects the elements needed to calculate evapotranspiration.
Temperature/Humidity Temperature: During the growing season, higher temperatures during daylight hours cause the plant stomata to open more resulting in greater transpiration. Humidity: The higher the humidity the less transpiration will occur (more transpiration occurs in dryer air)
Wind Movement As air movement across plant canopies increase, higher transpiration rates occur as the saturated air (from transpiration) ti around the plant is mixed with and replaced by and dryer air.
Solar Radiation Alfalfa only reflects about 25% of incoming solar energy which leaves ample solar energy to drive ET rates. ET trends follow a similar pattern as seasonal solar radiation and air temperature.
Precipitation Precipitation data are not used explicitly in the ET equations, but precipitation data are essential in determining crop water needs Monitoring precipitation also provides an idea of soil moisture availability at the station.
Soil Temperatures Having the temperature of the soil aids in knowing when the soil has warmed enough to plant. Soil temperature also gives an indication of the amount of ground cover at the station.
CoAgMet example ET Data Growing season Alfalfa reference ET for 2011 growing season comparing an unirrigated site near Delta to a partially irrigated site near Olathe
Please note: CoAgMet instrumentation are high quailty and the CoAgMet data are easily accessibly..... However
Problems with CoAgMet Missing data Site exposure Routine maintenance
Missing/Questionable Data Due to various problems that occur to remote weather stations, missing data causes problems for users. Battery failure and communications problems are the most common. Even if the whole station doesn t fail, sensors go bad and can leave some elements missing until the station is serviced.
Unfortunately, data are not complete at all stations 250 200 Peckham, Mean Monthly Wind Run (May Sept) p) Missing Data 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Mean Wind Run (m mi) 150 100 50 0 March April May June July August September October Month
Some Data are Questionable 18.00 CSU Fruita Experimental Station, Monthly Vapor Pressure (1992 2006) 1992 1993 16.00 1994 14.00 1995 1996 Vapor Pressure ( mb) Vapor Pressure (mb) 12.00 10.00 8.00 6.00 4.00 2.00 0.00 20.00 18.00 16.00 14.00 12.00 10.00 8.00 6.00 March April May June July August September October Month Lamar 01, Mean Monthly Vapor Pressure (1998 2006) 1998 1999 2000 2001 2002 2003 2004 2005 2006 Mean 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Mean Solar Radiation (Lgly) 700 600 500 400 300 200 100 0 Avondale, Mean Monthly Solar Radiation (1992 2006) March April May June July August September October Month 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Mean 4.00 2.00 0.00 March April May June July August September October Month
Site Exposure One of the assumptions s of the evapotranspiration a at o equations is that water is not limited (i.e. in full irrigation). Some stations are not located in ideal reference conditions. Some stations have obstructions (buildings/crops) that affect the amount of wind in certain directions. The exposure of the site can have an impact on the data and over/under estimate reference ET.
Siting and Exposure The Good and the Not so Good FTC01 Fort Collins AERC has appropriate p citing for reference ET calculations HOT01 Hotchkiss is not ideally cited for reference ET calculations
Routine Maintenance Due to the fact that CoAgMet is run by collaborations and operates on a limited budget, routine maintenance is difficult with such a large network. There is no full time CoAgMet technician. Our goal is to visit each station once a year to make sure the station is operating properly. Sensor are swapped out once every 2 years. Data users should be cautious and thoroughly quality control the data they are using.
Possible Solutions? Efforts are being made to fill in missing data using relationships with nearby stations. This data would be flagged when presented on the website. Our website now color codes stations according to their irrigation are classified as: full irrigation, partial irrigation and dryland. Making this information available to the public allows them to know more about their data source.
Possible Solutions? We do our best with limited funds to keep a maintenance schedule but it is very difficult. If we are not able to keep high standards for our weather stations, some current stations may need to be discontinued in the near future.
CoAgMet Website Demonstration
The Colorado Climate Center Home Page http://ccc.atmos.colostate.edu/
Hourly Climate Data Plots Click Here
Hourly Climate Data Plots Temperature GLY03 Greely June 9, 2007 through h June 15, 2007 Relative Humidity
Click Here Daily Climatic Summary
Daily Climatic Summary
Monthly Station Summaries Click Here
Monthly Station Summaries KSY01 Kersey Aug. 2007
Daily Regional Climatic and ET Comparison Click Here
Daily Regional Climatic and ET Comparison North Central Region, May 30, 2007
Click Here Crop Specific ET Reports
Crop Specific ET Reports Calculates multi-day ET for: alfalfa, corn, dry beans, small grain, sugar beets, potatoes, t onion, winter wheat, turf grass, and reference ET, via Penman-Monteith or Kimberly-Penman
CoAgMet web access: http://ccc.atmos.colostate.edu/~coagmet/