Batch Download of Daily Climate Data (SMN, NASA POWER, or Hybrid)

Downloads daily meteorological series for multiple stations from:

• SMN (official in-situ records),

• NASA POWER (satellite/reanalysis),

• Hybrid: joins SMN (full) + NASA POWER variables by station + date.

It harmonizes output columns (station metadata, date, core SMN variables, and optional NASA POWER variables) and returns either a single tidy data frame (row-bound) or a list per station.

Usage

smn_dl_daily_batch(
  stations,
  source = c("smn", "nasa", "hybrid"),
  start_date = "1961-01-01",
  end_date = Sys.Date(),
  output_format = c("full", "reduced"),
  del_na = c("no", "yes"),
  require_coords = TRUE,
  vars = c("T2M_MIN", "T2M_MAX", "PRECTOTCORR"),
  community = c("AG", "RE", "SB"),
  return_list = FALSE,
  .handlers = NULL,
  .progress = TRUE
)

Arguments

stations

Character/numeric vector of station codes or a data frame with at least a station column. For source = "nasa" or "hybrid", if latitude, longitude, altitude are present, they will be used directly; otherwise the function will try to resolve them (see require_coords).

source

One of "smn", "nasa", "hybrid", or a custom key present in .handlers.

start_date

Start date (inclusive). Date or character. Default "1961-01-01".

end_date

End date (inclusive). Date or character. Default Sys.Date().

output_format

Output format: "full" (default) or "reduced".

• full: station, latitude, longitude, altitude, date, prec, evap, tmax, tmin

• reduced: date, prec, evap, tmax, tmin

del_na

"no" (default) or "yes". If "yes", rows containing NA are dropped at the end.

require_coords

Logical. For "nasa"/"hybrid": attempt to resolve missing coordinates using smn_int_extract_coordinates() when latitude/longitude are not provided in stations.

vars

Character vector with NASA POWER parameter codes used in source = "nasa" or "hybrid" (e.g., c("T2M_MIN","T2M_MAX","PRECTOTCORR")).

community

NASA POWER community for "nasa"/"hybrid"; one of "AG", "RE", "SB" (default "AG").

return_list

Logical; if TRUE, returns a named list (one element per station). If FALSE (default), returns a single tidy data frame with all rows bound.

.handlers

Optional named list of custom handlers with signature function(station, start_date, end_date, output_format, del_na, row, vars, community).

.progress

Logical. Show a simple text progress bar while downloading.

Value

A data frame (default) with all stations row-bound in chronological order per station, or a named list of per-station data frames when return_list = TRUE.

Details

Output columns depend on source:

• source = "smn": station, latitude, longitude, altitude, date, prec, evap, tmax, tmin (or reduced set if output_format = "reduced").

• source = "nasa": station, latitude, longitude, altitude, date + requested vars.

• source = "hybrid": union of SMN core variables + requested NASA vars.

If some branch fails for a given station, the function continues and returns what is available (empty data frame for that station), warning as needed. When return_list = FALSE, results are row-bound in the end, keeping a consistent column order per source.

Custom handlers

You can extend sources via .handlers, e.g.:

  my_h <- list(
    era5 = function(station, start_date, end_date, output_format, del_na, row, vars, community) {
      # ... your downloader; must return a data.frame with at least
      # station, date, latitude, longitude, altitude, and variables
    }
  )
  smn_dl_daily_batch(stations = c("15021","15101"),
                     source = "era5",
                     start_date = "2000-01-01", end_date = "2000-01-10",
                     .handlers = my_h)

See also

smn_dl_daily_single, smn_dl_daily_nasa, smn_int_extract_coordinates

Examples

if (FALSE) { # \dontrun{
# --- Minimal examples (short date window) ---

# 1) SMN only (two stations, short period)
df_smn <- smn_dl_daily_batch(
  stations = c("15021","15101"),
  source   = "smn",
  start_date = "2020-01-01",
  end_date   = "2020-01-05",
  output_format = "full",
  del_na = "no",
  .progress = TRUE
)
head(df_smn)

# 2) NASA POWER only — if you already know coordinates for each station
st <- data.frame(
  station   = c("X15021","X15101"),
  latitude  = c(19.35, 19.70),
  longitude = c(-99.10, -99.20),
  altitude  = c(2250, 2400)
)
df_nasa <- smn_dl_daily_batch(
  stations = st,
  source   = "nasa",
  start_date = "2020-01-01",
  end_date   = "2020-01-03",
  vars = c("T2M_MIN","T2M_MAX","PRECTOTCORR"),
  community = "AG",
  .progress = FALSE
)
head(df_nasa)

# 3) HYBRID (SMN + NASA POWER merged by station/date)
df_hyb <- smn_dl_daily_batch(
  stations = c("15021","15101"),
  source   = "hybrid",
  start_date = "2020-01-01",
  end_date   = "2020-01-05",
  vars = c("T2M_MIN","T2M_MAX","PRECTOTCORR"),
  .progress = TRUE
)
head(df_hyb)
} # }