get_ghcn_daily: Download and crop the Global Historical Climate Network-Daily...

In FedData: Functions to Automate Downloading Geospatial Data Available from Several Federated Data Sources

Description

get_ghcn_daily returns a named list of length 2:

1. 'spatial': A SpatialPointsDataFrame of the locations of GHCN weather stations in the template, and

2. 'tabular': A named list of data.frames with the daily weather data for each station. The name of each list item is the station ID.

Usage

get_ghcn_daily(template = NULL, label = NULL, elements = NULL,
  years = NULL, raw.dir = "./RAW/GHCN",
  extraction.dir = paste0("./EXTRACTIONS/", label, "/GHCN"),
  standardize = F, force.redo = F)

Arguments

template	A Raster* or Spatial* object to serve as a template for cropping. Alternatively, a character vector providing GHCN station IDs. If missing, all stations will be downloaded!
label	A character string naming the study area.
elements	A character vector of elemets to extract. The five core elements are: PRCP = Precipitation (tenths of mm) SNOW = Snowfall (mm) SNWD = Snow depth (mm) TMAX = Maximum temperature (tenths of degrees C) TMIN = Minimum temperature (tenths of degrees C) The other elements are: ACMC = Average cloudiness midnight to midnight from 30-second ceilometer data (percent) ACMH = Average cloudiness midnight to midnight from manual observations (percent) ACSC = Average cloudiness sunrise to sunset from 30-second ceilometer data (percent) ACSH = Average cloudiness sunrise to sunset from manual observations (percent) AWDR = Average daily wind direction (degrees) AWND = Average daily wind speed (tenths of meters per second) DAEV = Number of days included in the multiday evaporation total (MDEV) DAPR = Number of days included in the multiday precipiation total (MDPR) DASF = Number of days included in the multiday snowfall total (MDSF) DATN = Number of days included in the multiday minimum temperature (MDTN) DATX = Number of days included in the multiday maximum temperature (MDTX) DAWM = Number of days included in the multiday wind movement (MDWM) DWPR = Number of days with non-zero precipitation included in multiday precipitation total (MDPR) EVAP = Evaporation of water from evaporation pan (tenths of mm) FMTM = Time of fastest mile or fastest 1-minute wind (hours and minutes, i.e., HHMM) FRGB = Base of frozen ground layer (cm) FRGT = Top of frozen ground layer (cm) FRTH = Thickness of frozen ground layer (cm) GAHT = Difference between river and gauge height (cm) MDEV = Multiday evaporation total (tenths of mm; use with DAEV) MDPR = Multiday precipitation total (tenths of mm; use with DAPR and DWPR, if available) MDSF = Multiday snowfall total MDTN = Multiday minimum temperature (tenths of degrees C; use with DATN) MDTX = Multiday maximum temperature (tenths of degress C; use with DATX) MDWM = Multiday wind movement (km) MNPN = Daily minimum temperature of water in an evaporation pan (tenths of degrees C) MXPN = Daily maximum temperature of water in an evaporation pan (tenths of degrees C) PGTM = Peak gust time (hours and minutes, i.e., HHMM) PSUN = Daily percent of possible sunshine (percent) SN*# = Minimum soil temperature (tenths of degrees C) where * corresponds to a code for ground cover and # corresponds to a code for soil depth. Ground cover codes include the following: 0 = unknown 1 = grass 2 = fallow 3 = bare ground 4 = brome grass 5 = sod 6 = straw multch 7 = grass muck 8 = bare muck Depth codes include the following: 1 = 5 cm 2 = 10 cm 3 = 20 cm 4 = 50 cm 5 = 100 cm 6 = 150 cm 7 = 180 cm SX*# = Maximum soil temperature (tenths of degrees C) where * corresponds to a code for ground cover and # corresponds to a code for soil depth. See SN*# for ground cover and depth codes. TAVG = Average temperature (tenths of degrees C) [Note that TAVG from source 'S' corresponds to an average for the period ending at 2400 UTC rather than local midnight] THIC = Thickness of ice on water (tenths of mm) TOBS = Temperature at the time of observation (tenths of degrees C) TSUN = Daily total sunshine (minutes) WDF1 = Direction of fastest 1-minute wind (degrees) WDF2 = Direction of fastest 2-minute wind (degrees) WDF5 = Direction of fastest 5-second wind (degrees) WDFG = Direction of peak wind gust (degrees) WDFI = Direction of highest instantaneous wind (degrees) WDFM = Fastest mile wind direction (degrees) WDMV = 24-hour wind movement (km) WESD = Water equivalent of snow on the ground (tenths of mm) WESF = Water equivalent of snowfall (tenths of mm) WSF1 = Fastest 1-minute wind speed (tenths of meters per second) WSF2 = Fastest 2-minute wind speed (tenths of meters per second) WSF5 = Fastest 5-second wind speed (tenths of meters per second) WSFG = Peak gust wind speed (tenths of meters per second) WSFI = Highest instantaneous wind speed (tenths of meters per second) WSFM = Fastest mile wind speed (tenths of meters per second) WT** = Weather Type where ** has one of the following values: 01 = Fog, ice fog, or freezing fog (may include heavy fog) 02 = Heavy fog or heaving freezing fog (not always distinquished from fog) 03 = Thunder 04 = Ice pellets, sleet, snow pellets, or small hail 05 = Hail (may include small hail) 06 = Glaze or rime 07 = Dust, volcanic ash, blowing dust, blowing sand, or blowing obstruction 08 = Smoke or haze 09 = Blowing or drifting snow 10 = Tornado, waterspout, or funnel cloud 11 = High or damaging winds 12 = Blowing spray 13 = Mist 14 = Drizzle 15 = Freezing drizzle 16 = Rain (may include freezing rain, drizzle, and freezing drizzle) 17 = Freezing rain 18 = Snow, snow pellets, snow grains, or ice crystals 19 = Unknown source of precipitation 21 = Ground fog 22 = Ice fog or freezing fog WV** = Weather in the Vicinity where ** has one of the following values: 01 = Fog, ice fog, or freezing fog (may include heavy fog) 03 = Thunder 07 = Ash, dust, sand, or other blowing obstruction 18 = Snow or ice crystals 20 = Rain or snow shower
years	A numeric vector indicating which years to get.
raw.dir	A character string indicating where raw downloaded files should be put. The directory will be created if missing. Defaults to './RAW/GHCN/'.
extraction.dir	A character string indicating where the extracted and cropped GHCN shapefiles should be put. The directory will be created if missing. Defaults to './EXTRACTIONS/GHCN/'.
standardize	Select only common year/month/day? Defaults to FALSE.
force.redo	If an extraction for this template and label already exists, should a new one be created? Defaults to FALSE.

Value

A named list containing the 'spatial' and 'tabular' data.

Examples

## Not run: 
# Extract data for the Village Ecodynamics Project 'VEPIIN' study area:
# http://village.anth.wsu.edu
vepPolygon <- polygon_from_extent(raster::extent(672800,740000,4102000,4170000), 
     proj4string='+proj=utm +datum=NAD83 +zone=12')

# Get the daily GHCN data (GLOBAL)
# Returns a list: the first element is the spatial locations of stations,
# and the second is a list of the stations and their daily data
GHCN.prcp <- get_ghcn_daily(template=vepPolygon, label='VEPIIN', elements=c('prcp'))

# Plot the VEP polygon
plot(vepPolygon)

# Plot the spatial locations
plot(GHCN.prcp$spatial, pch=1, add=T)
legend('bottomleft', pch=1, legend='GHCN Precipitation Records')

# Elements for which you require the same data
# (i.e., minimum and maximum temperature for the same days)
# can be standardized using standardize==T
GHCN.temp <- get_ghcn_daily(template=vepPolygon, 
     label='VEPIIN', 
     elements=c('tmin','tmax'), 
     standardize=T)

# Plot the VEP polygon
plot(vepPolygon)

# Plot the spatial locations
plot(GHCN.temp$spatial, pch=1, add=T)
legend('bottomleft', pch=1, legend='GHCN Temperature Records')

## End(Not run)

FedData documentation built on May 30, 2017, 7:56 a.m.

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