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Decode multiple SYNOP messages from a single station

Source: R/decoder.R
show_synop_data.Rd

This function decodes a vector or data frame column of raw SYNOP strings belonging to the same WMO station. It efficiently processes multiple observations at once, returning a tidy data frame.

Usage

show_synop_data(data, wmo_identifier = NULL, remove_empty_cols = FALSE)

Arguments

data

A character vector, or a data frame or tibble with one column containing raw SYNOP strings.

wmo_identifier

A 5-digit character string or integer representing the station WMO ID. If NULL (default), all messages are decoded.

remove_empty_cols

Logical. Should columns containing only NA values be removed?

Value

A tidy tibble where each row represents one observation time and each column a decoded meteorological variable.

  1. wmo_id - WMO station identifier

  2. Year - (from parse_ogimet())

  3. Day - As informed by Section 0

  4. Hour - As informed by Section 0

  5. Cloud_base_height - Lowest cloud base height, not decoded

  6. Visibility - Not decoded

  7. Total_cloud_cover - In oktas, 9 means 'invisible' sky by fog or other phenomenon

  8. Wind_direction - In tens of degree, 99 means 'variable wind direction'

  9. Wind_speed

  10. Wind_speed_unit - Either 'm/s' or 'knots'

  11. Air_temperature - In degrees Celsius

  12. Dew_point - In degrees Celsius

  13. Relative_humidity - As a percentage

  14. Station_pressure - In hPa

  15. MSLP_GH - Mean sea level pressure (in hPa) or geopotential height (in gpm)

  16. Present_weather - Not decoded

  17. Past_weather1 - Not decoded

  18. Past_weather2 - Not decoded

  19. Precipitation_S1 - In mm

  20. Precip_period_S1 - In hours ('Precipitation_S1' fell in the last 'Precip_period_S1' hours)

  21. Cloud_amount_Nh - Cloud coverage from low or medium cloud, same as 'Total_cloud_cover'

  22. Low_clouds_CL - Not decoded

  23. Medium_clouds_CM - Not decoded

  24. High_clouds_CH - Not decoded

  25. Max_temperature - In degrees Celsius

  26. Min_temperature - In degrees Celsius

  27. Ground_state - Not decoded

  28. Ground_temperature - Integer, in degrees Celsius

  29. Snow_ground_state - Not decoded

  30. Snow_depth - In cm, is assumed to be between 1 and 996 cm

  31. Precipitation_S3 - In mm

  32. Precip_period_S3 - In hours ('Precipitation_S3' fell in the last 'Precip_period_S3' hours)

Examples

msg <- paste0("AAXX 01123 87736 32965 13205 10214 20143 ",
              "30022 40113 5//// 80005 333 10236 20128 56000 81270=")
synop_df <- data.frame(messages = msg)
decoded_data <- show_synop_data(synop_df, "87736")