cmi_weather_data {BioCro}

Champaign, IL weather data

Description

Champaign, IL weather data specified at hourly intervals in the CST time zone for the years 1995–2023. The data includes typical inputs required for BioCro imulations. Note: some values are missing near the start of 1995 since those time points are not available from SURFRAD.

This weather data is included in the BioCro package so users can reproduce the calculations of Lochocki et al. (2022) [doi:10.1093/insilicoplants/diac003] and for exploratory purposes; it is likely that most BioCro studies will require different data sets, and no attempt is made here to be exhaustive.

Usage

weather

Format

A list of 29 named elements, where each element is a data frame corresponding to one year of weather data and the name of each element is a year, for example '2004'. Each data frame has 8760 or 8784 observations (representing hourly time points) of 9 variables:

• year: the year

• doy: the day of year

• hour: the hour

• time_zone_offset: the time zone offset relative to UTC (hr)

• precip: preciptation rate (mm / hr)

• rh: the ambient relative humidity (dimensionless)

• solar: the incoming photosynthetically active photon flux density (PPFD) measured on a ground area basis including direct and diffuse sunlight light just outside the crop canopy (micromol / m^2 / s)

• temp: the ambient air temperature (degrees Celsius)

• windspeed: the wind speed in the ambient air just outside the canopy (m / s)

Source

Weather data were obtained from the public SURFRAD and WARM databases and processed according to the method described in Lochocki et al. (2022) [doi:10.1093/insilicoplants/diac003]. See version 1.2.0 of the eloch216/oscillator-based-circadian-clock-analysis GitHub repository for a full description of the data processing.

In brief, the columns in the data frames were determined from SURFRAD and WARM variables as follows:

• precip: from the precip variable in the WARM data set

• rh: from the rh variable in the SURFRAD data set

• solar: from the par variable in the SURFRAD data set; when these values are not available, the direct_n, diffuse, and zen variables are used to make an estimate

• temp: from the temp variable in the SURFRAD data set

• windspeed: from the windspd variable in the SURFRAD data set

The WARM data set includes daily values. Hourly values for precipitation are derived from daily totals by assuming a constant rate of precipitation throughout the day.

The SURFRAD data set includes values at 1 or 3 minute intervals. Hourly values are determined by averaging over hourly intervals, where the value at hour h is the average over the hour-long interval centered at h. Some values are missing; any missing entries are filled via an interpolation procedure based on the assumption that values at the same hour of sequential days should be similar.

The time_zone_offset is set to a constant value of -6 since this data is specified in the CST time zone (i.e., UTC-6). Since the value of this quantity does not change, it could in principle be considered a parameter rather than a driver; however, it is included with the weather data for convenience.

To reduce size the in the BioCro repository, the raw data values are rounded. This was done using the commands in a script that is included with the BioCro package. This script can be located by typing system.file('BioCro', 'extdata', 'rounding_weather_values.R').