Package 'worldmet'

Export a meteorological data frame in ADMS format

Description

Writes a text file in the ADMS format to a location of the user's choosing, with optional interpolation of missing values.

Usage

exportADMS(dat, out = "./ADMS_met.MET", interp = FALSE, maxgap = 2)

Arguments

dat	A data frame imported by importNOAA().
out	A file name for the ADMS file. The file is written to the working directory by default.
interp	Should interpolation of missing values be undertaken? If TRUE linear interpolation is carried out for gaps of up to and including maxgap.
maxgap	The maximum gap in hours that should be interpolated where there are missing data when interp = TRUE. Data with gaps more than maxgap are left as missing.

Value

exportADMS() returns the input dat invisibly.

Examples

## Not run: 
## import some data then export it
dat <- importNOAA(year = 2012)
exportADMS(dat, out = "~/adms_met.MET")

## End(Not run)

---

Find a ISD site code and other meta data

Description

Get information on meteorological sites

Usage

getMeta(
  site = "heathrow",
  lat = NA,
  lon = NA,
  country = NA,
  state = NA,
  n = 10,
  end.year = "current",
  provider = c("OpenStreetMap", "Esri.WorldImagery"),
  plot = TRUE,
  returnMap = FALSE
)

Arguments

site	A site name search string e.g. site = "heathrow". The search strings and be partial and can be upper or lower case e.g. site = "HEATHR".
lat	A latitude in decimal degrees to search. Takes the values -90 to 90.
lon	A longitude in decimal degrees to search. Takes values -180 to 180. Negative numbers are west of the Greenwich meridian.
country	The country code. This is a two letter code. For a full listing see https://www1.ncdc.noaa.gov/pub/data/noaa/isd-history.csv.
state	The state code. This is a two letter code.
n	The number of nearest sites to search based on latitude and longitude.
end.year	To help filter sites based on how recent the available data are. end.year can be "current", "any" or a numeric year such as 2016, or a range of years e.g. 1990:2016 (which would select any site that had an end date in that range. By default only sites that have some data for the current year are returned.
provider	By default a map will be created in which readers may toggle between a vector base map and a satellite/aerial image. provider allows users to override this default; see http://leaflet-extras.github.io/leaflet-providers/preview/ for a list of all base maps that can be used. If multiple base maps are provided, they can be toggled between using a "layer control" interface.
plot	If TRUE will plot sites on an interactive leaflet map.
returnMap	Should the leaflet map be returned instead of the meta data? Default is FALSE.

Details

This function is primarily used to find a site code that can be used to access data using importNOAA(). Sites searches of approximately 30,000 sites can be carried out based on the site name and based on the nearest locations based on user-supplied latitude and longitude.

Value

A data frame is returned with all available meta data, mostly importantly including a code that can be supplied to importNOAA(). If latitude and longitude searches are made an approximate distance, dist in km is also returned.

Author(s)

David Carslaw

See Also

getMetaLive() to download the all meta data to allow re-use and direct querying.

Examples

## Not run: 
## search for sites with name beijing
getMeta(site = "beijing")

## End(Not run)

## Not run: 
## search for near a specified lat/lon - near Beijing airport
## returns 'n' nearest by default
getMeta(lat = 40, lon = 116.9)

## End(Not run)

---

Obtain site meta data from NOAA server

Description

Download all NOAA meta data, allowing for re-use and direct querying.

Usage

getMetaLive(...)

Arguments

...	Currently unused.

Value

a tibble

Examples

## Not run: 
meta <- getMetaLive()
head(meta)

## End(Not run)

---

Import Meteorological data from the NOAA Integrated Surface Database (ISD)

Description

This is the main function to import data from the NOAA Integrated Surface Database (ISD). The ISD contains detailed surface meteorological data from around the world for over 30,000 locations. For general information of the ISD see https://www.ncei.noaa.gov/products/land-based-station/integrated-surface-database and the map here https://gis.ncdc.noaa.gov/maps/ncei.

Usage

importNOAA(
  code = "037720-99999",
  year = 2014,
  hourly = TRUE,
  n.cores = 1,
  quiet = FALSE,
  path = NA
)

Arguments

code	The identifying code as a character string. The code is a combination of the USAF and the WBAN unique identifiers. The codes are separated by a “-” e.g. code = "037720-99999".
year	The year to import. This can be a vector of years e.g. year = 2000:2005.
hourly	Should hourly means be calculated? The default is TRUE. If FALSE then the raw data are returned.
n.cores	Number of cores to use for parallel processing. Default is 1 and hence no parallelism.
quiet	If FALSE, print missing sites / years to the screen, and show a progress bar if multiple sites are imported.
path	If a file path is provided, the data are saved as an rds file at the chosen location e.g. path = "C:/Users/David". Files are saved by year and site.

Details

Note the following units for the main variables:

date

Date/time in POSIXct format. Note the time zone is GMT (UTC) and may need to be adjusted to merge with other local data. See details below.

latitude

Latitude in decimal degrees (-90 to 90).

longitude

Longitude in decimal degrees (-180 to 180). Negative numbers are west of the Greenwich Meridian.

elevation

Elevation of site in metres.

wd

Wind direction in degrees. 90 is from the east.

ws

Wind speed in m/s.

ceil_hgt

The height above ground level (AGL) of the lowest cloud or obscuring phenomena layer aloft with 5/8 or more summation total sky cover, which may be predominantly opaque, or the vertical visibility into a surface-based obstruction.

visibility

The visibility in metres.

air_temp

Air temperature in degrees Celcius.

dew_point

The dew point temperature in degrees Celcius.

atmos_pres

The sea level pressure in millibars.

RH

The relative humidity (%).

cl_1, ..., cl_3

Cloud cover for different layers in Oktas (1-8).

cl

Maximum of cl_1 to cl_3 cloud cover in Oktas (1-8).

cl_1_height, ..., cl_3_height

Height of the cloud base for each later in metres.

precip_12

12-hour precipitation in mm. The sum of this column should give the annual precipitation.

precip_6

6-hour precipitation in mm.

precip

This value of precipitation spreads the 12-hour total across the previous 12 hours.

pwc

The description of the present weather description (if available).

The data are returned in GMT (UTC). It may be necessary to adjust the time zone when combining with other data. For example, if air quality data were available for Beijing with time zone set to "Etc/GMT-8" (note the negative offset even though Beijing is ahead of GMT. See the openair package and manual for more details), then the time zone of the met data can be changed to be the same. One way of doing this would be attr(met$date, "tzone") <- "Etc/GMT-8" for a meteorological data frame called met. The two data sets could then be merged based on date.

Value

Returns a data frame of surface observations. The data frame is consistent for use with the openair package. Note that the data are returned in GMT (UTC) time zone format. Users may wish to express the data in other time zones, e.g., to merge with air pollution data. The lubridate package is useful in this respect.

Author(s)

David Carslaw

See Also

getMeta() to obtain the codes based on various site search approaches.

Examples

## Not run: 
## use Beijing airport code (see getMeta example)
dat <- importNOAA(code = "545110-99999", year = 2010:2011)

## End(Not run)

---

Codes for weather types

Description

This data frame consists of the weather description codes used in the ISD. It is not of general use to most users.

Usage

weatherCodes

Format

An object of class tbl_df (inherits from tbl, data.frame) with 100 rows and 2 columns.

Details

pwc

Weather code, which can be merged with the pwc column in importNOAA() datasets.

description

Description associated with the weather codes.

Examples

weatherCodes

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