hourlyNCEP | R Documentation |
hourlyNCEP
optionally downloads the required NCEP climate and radiation forcing data
required for running microclima and interpolates 4x daily data to hourly.
hourlyNCEP(ncepdata = NA, lat, long, tme, reanalysis2 = FALSE)
ncepdata |
an optional data frame of climate variables as returned by |
lat |
the latitude of the location for which data are required. Ignored if |
long |
the longitude of the location for which data are required. Ignored if |
tme |
a POSIXlt object covering the duration for which data are required. Ignored if |
reanalysis2 |
Logical. Should data be obtained from the Reanalysis II dataset (default) or
from Reanalysis I (data prior to 1979). Ignored if |
If ncepdata
is not provided, then get_NCEP()
is called and data are downloaded from NCEP Atmospheric
Model Intercomparison Project (Kanamitso et al 2002). Six-hourly data are interpolated as follows.
Pressure, humidity and the u and v wind vectors are converted to hourly using spline interpolation. Wind speeed and direction and then
calculated and adjusted to give values at 1 m using windheight()
. The diffuse radiation
proportion is calculated using difprop()
, and hourly obtained by adusting for the direction
of the solar beam and airmass thickness using functions siflat()
and airmasscoef()
.
Hourly temperature are derived using hourlytemp()
and longwave radiation by splining emissivity
values.
a dataframe with the following variables:
POSIXlt object of times in UTC
emperatures at 2m (ºC)
specific humidity at 2m (Kg / Kg)
surface pressure (Pa)
wind speed at 2m (metres per second
wind direction (degrees from N)
emissivity of the atmosphere (0 - 1, downlong / uplong)
Net longwave radiation (MJ m-2 hr-1)
Upward longwave radiation (MJ m-2 hr-1)
Downward longwave radiation (MJ m-2 hr-1)
Direct radiation normal to the solar beam (MJ m-2 hr-1)
Diffuse radiation (MJ m-2 hr-1)
the zenith angle (degrees)
cloud cover (Percentage)
get_NCEP()
tme <- as.POSIXlt(c(0:30) * 24 * 3600, origin ="2015-01-15 00:00", tz = "UTC")
# NB takes a while to download data
hdata<- hourlyNCEP(NA, 50, -5, tme)
head(hdata)
plot(temperature ~ as.POSIXct(obs_time), data = hdata, type = "l", xlab = "Month")
plot(rad_dif ~ as.POSIXct(obs_time), data = hdata, type = "l", xlab = "Month")
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.