1 Contextualization

The BrazilMet package is a compilation of functions to download and processing Automatic Weather Stations (AWS) data of INMET-Brazil, with the purpose of reference evapotranspiration (ETo) estimation. The package aims to make meteorological and agricultural data analysis more parsimonious.

2 Loading and installing the package

#install.packages("BrazilMet")
library(BrazilMet)

3 Looking the available weather stations

To see the weather stations available, you can use the function see_stations_info. These funtions have the purpose of guiding the users, when they are going to run the functions download_AWS_INMET_daily.

see_stations_info()
## # A tibble: 589 x 4
##    OMM   Latitude Longitude Altitude
##    <chr>    <dbl>     <dbl>    <dbl>
##  1 A001     -15.8     -47.9    1161.
##  2 A042     -15.6     -48.1    1143 
##  3 A045     -15.6     -47.6    1030.
##  4 A046     -15.9     -48.1     990 
##  5 A047     -16.0     -47.6    1043 
##  6 A002     -16.6     -49.2     727.
##  7 A003     -17.7     -49.1     751.
##  8 A005     -13.3     -49.1     365 
##  9 A011     -19.0     -50.6     492.
## 10 A012     -16.3     -48.0    1001.
## # ... with 579 more rows

4 Downloading the AWS data for one station during one year

To download the AWS data on BrazilMet package you have to use the download_AWS_INMET_daily. Let’s see the example for stations "A001", which are located in Brasilia-DF.

df<-download_AWS_INMET_daily(station = "A001", start_date = "2001-01-01", end_date = "2001-12-31")

4.1 Daily reference evapotranspiration based on FAO-56 Penman-Monteith

eto <- daily_eto_FAO56(lat = df$`Latitude (degrees)`,
                       tmin = df$`Tair_min (c)`,
                       tmax = df$`Tair_max (c)`,
                       tmean = df$`Tair_mean (c)`,
                       Rs = df$`Sr (Mj m-2 day-1)`,
                       u2 = df$`Ws_2 (m s-1)`,
                       Patm = df$`Patm (mB)`,
                       RH_max = df$`Rh_max (porc)`,
                       RH_min = df$`Rh_min (porc)`,
                       z = df$`Altitude (m)`,
                       date = df$Date)

More about the ETo method used in this package see the reference of Allen et al. (1998) 1.

Hope that you enjoyed and see the other functionalities of our package!

5 References

  1. ALLEN, R. G.; PEREIRA, L. S.; RAES, D.; SMITH, M. Crop evapotranspiration: guidelines for computing crop water requirements. Rome: FAO, 1998. 300 p. (Irrigation and Drainage Paper, 56)↩︎