Main function for importing meteorological data

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". The year to import. This can be a vector of years e.g. year = 2000:2005. Should hourly means be calculated? The default is TRUE. If FALSE then the raw data are returned. Number of cores to use for parallel processing. Default is 1 and hence no parallelism. If FALSE, print missing sites / years to the screen. 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.

## Value

Returns a data frame of surface observations. The data frame is consistent for use with the openair package. NOTE! 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.

## Details

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.ncdc.noaa.gov/isd and the map here https://gis.ncdc.noaa.gov/maps/ncei.

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

Elevention 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 calue 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.

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

David Carslaw

## Examples


if (FALSE) {
## use Beijing airport code (see getMeta example)
dat <- importNOAA(code = "545110-99999", year = 2010:2011)
}