
Import "Lite" Meteorological data from the NOAA Integrated Surface Database (ISD)
Source:R/importNOAAlite.R
importNOAAlite.Rd
This function is an alternative to importNOAA()
, and provides access to the
"Lite" format of the data. This a subset of the larger importNOAA()
dataset
featuring eight common climatological variables. As it assigns the nearest
measurement to the "top of the hour" to the data, specific values are likely
similar but different to those returned by importNOAA()
. Read the
technical document
for more information.
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 β-β e.g.
code = "037720-99999"
.- year
The year to import. This can be a vector of years e.g.
year = 2000:2005
.- quiet
If
FALSE
, print missing sites / years to the screen, and show a progress bar if multiple sites are imported.
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.
Details
Note the following units for the main variables:
- date
Date/time in POSIXct format. **Note the time zone is UTC and may need to be adjusted to merge with other local data.
- latitude
Latitude in decimal degrees (-90 to 90).
- longitude
Longitude in decimal degrees (-180 to 180). Negative numbers are west of the Greenwich Meridian.
- elev
Elevation of site in metres.
- ws
Wind speed in m/s.
- wd
Wind direction in degrees. 90 is from the east.
- air_temp
Air temperature in degrees Celcius.
- atmos_pres
The sea level pressure in millibars.
- dew_point
The dew point temperature in degrees Celcius.
- precip_6
6-hour precipitation in mm.
- precip_1
1-hour precipitation in mm.
- sky
Sky Condition Total Coverage Code.
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
.
See also
getMeta()
to obtain the codes based on various site search
approaches.
Other NOAA ISD functions:
getMeta()
,
getMetaLive()
,
importNOAA()