DOI: 10.5281/zenodo.18122156
title: CONUS-AgWeather, a high-quality benchmark daily agricultural weather station dataset for evapotranspiration applications in the Contiguous United States

description: Agricultural weather data are fundamental for the accurate estimate of evapotranspiration (ET), irrigation scheduling, and water-use accounting. In particular, reference ET provides a standardized atmospheric demand for water loss from a hypothetical well-watered grass (ETo) or alfalfa (ETr); however, weather stations may not adequately represent such climatic conditions. Weather data commonly contain errors from poor siting, sensor drift, and network management deficiencies. No standardized dataset exists over the contiguous United States (CONUS). Systematic errors affect ETo/ETr calculations and derived products. Notably, satellite-based platforms like OpenET require agricultural weather data to bias correct gridded reference ET to interpolate between satellite overpasses. CONUS-AgWeather is a benchmark dataset of daily agricultural weather data (precipitation, solar radiation, air temperature, humidity, wind speed, ETo, ETr) from 793 stations. This dataset contains 4,191,808 days (11,484 station-years, 1981-2020) and was produced through standardized and systematic quality control procedures and open-source software packages for time series inspection, outlier detection, corrections, and ETo/ETr calculations. CONUS-AgWeather is intended primarily to support OpenET in the Western U.S. but has broader applications.
description: Data Records

Each station record within the CONUS-AgWeather dataset includes the following 23 standardized variables, with the ones in bold font used in the ASCE-PM reference ET calculation:

1)     Station ID: Unique identifier for the weather station (<Number>_<State abbreviation>, e.g., 001_AR).

2)     Latitude: Latitude of the weather station in decimal degrees (0.0001°). Some networks report at a reduced precision to protect the privacy of the landowner.

3)     Longitude: Longitude of the weather station in decimal degrees (0.0001°). Some networks report at a reduced precision to protect the privacy of the landowner.

4)     Elevation: Elevation of the weather station in meters.

5)     Date: Observation date (YYYY-MM-DD).

6)     TMax: Daily maximum air temperature (°C).

7)     TAvg: Daily average air temperature (°C), computed as the average of the daily maximum and minimum temperatures.

8)     TMin: Daily minimum air temperature (°C).

9)     Ea: Daily mean vapor pressure (kPa), either directly from the QC’d record or calculated using agweather-qaqc. If Ea was calculated, agweather-qaqc used only the most preferred form of humidity data available as specified in the ASCE-EWRI standard. Note that preferred humidity data was QC’d prior to calculation of Ea if Ea was not provided directly (e.g., when only RHMax and RHMin are provided in the observational record).

10)  TDew: Daily average dew point temperature (°C), either from the QC’d record or calculated.

11)  RHMax: Daily maximum relative humidity (%). This variable may not be present if it is not provided by the weather station network. RHMax is used in the ASCE-PM reference ET calculation only if Ea or TDew are not provided in the observational record.

12)  RHAvg: Daily average relative humidity (%). This variable may not be present if it is not provided by the weather station network. RHAvg is only used in the ASCE-PM reference ET calculation if no other sources of humidity observations are provided in the record.

13)  RHMin: Daily minimum relative humidity (%). This variable may not be present if it is not provided by the weather station network. RHMin is used in the ASCE-PM reference ET calculation only if measured Ea or TDew are not provided in the observational record.

14)  Compiled Ea: Daily mean water vapor (kPa). This is an aggregate record that uses all forms of humidity data present, not just the most preferred, to calculate as complete a record of Rso as possible for the QC of Rs.

15)  Rs: Average daily incoming shortwave solar radiation (W m⁻²).

16)  Optimized TR Rs: Optimized Thornton-Running solar radiation (W m⁻²), which computes a modeled version of incoming shortwave radiation according to Thornton and Running’s equation 59. This variable is calculated to provide the option of a full record of solar radiation but is separate from QC’d observations of solar radiation.

17)  Rso: Computed clear-sky solar radiation (W m⁻²) for QC of observed Rs. The values are computed using station latitude and equations that model the effects of precipitable water in the atmosphere on incoming solar radiation, as described in the ASCE-EWRI (2005).

18)  Measured Uz: Daily average wind speed at the actual height of the anemometer (m s⁻¹).

19)  Anemometer Height: Height of the anemometer at the station (m).

20)  Uz at 2m: Daily average wind speed adjusted to 2m height (m s⁻¹).

21)  Precipitation: Daily total precipitation (mm).

22)  ETo: Daily grass reference ET (mm).

23) ETr: Daily alfalfa reference ET (mm).

 




Variable
Number of site-days


ETo
4,191,808


ETr
4,191,808


TMax
4,438,309


TAvg
4,419,341


TMin
4,429,262


Ea
4,266,271


TDew
4,273,626


RHMax
2,309,036


RHAvg
2,747,913


RHMin
2,311,291


Compiled Ea
4,381,446


Rs
4,343,533


Optimized TR Rs
4,396,370


Rso
4,375,944


Measured Uz
4,375,840


Anemometer Height
4,644,001


Uz at 2m
4,375,840


Precipitation
4,512,874




Data Format and Availability

The CONUS-AgWeather dataset is publicly available as a zip file, containing Microsoft Excel spreadsheets for individual stations. Detailed metadata with station-specific QC notes, human readable plaintext log files, and interactive HTML Bokeh plots of the pre-and post- QC datasets. The period of record for each station varies, and this information is included in the metadata.