importTraj: Import pre-calculated HYSPLIT 96-hour back trajectories
In openair: Tools for the Analysis of Air Pollution Data
importTraj R Documentation
Import pre-calculated HYSPLIT 96-hour back trajectories
Description
Function to import pre-calculated back trajectories using the NOAA HYSPLIT
model. The trajectories have been calculated for a select range of locations
which will expand in time. They cover the last 20 years or so and can be used
together with other openair functions.
Usage
importTraj(site = "london", year = 2009, local = NA, progress = TRUE)
Arguments
site
Site code of the network site to import e.g. "london". Only one
site can be imported at a time. The following sites are typically available
from 2000-2012, although some UK ozone sites go back to 1988 (code,
location, lat, lon, year):
abudhabi Abu Dhabi 24.43000 54.408000 2012-2013
ah Aston Hill 52.50385 -3.041780 1988-2013
auch Auchencorth Moss 55.79283 -3.242568 2006-2013
berlin Berlin, Germany 52.52000 13.400000 2000-2013
birm Birmigham Centre 52.47972 -1.908078 1990-2013
boston Boston, USA 42.32900 -71.083000 2008-2013
bot Bottesford 52.93028 -0.814722 1990-2013
bukit Bukit Kototabang, Indonesia -0.19805 100.318000 1996-2013
chittagong Chittagong, Bangladesh 22.37000 91.800000 2010-2013
dhaka Dhaka, Bangladesh 23.70000 90.375000 2010-2013
ed Edinburgh 55.95197 -3.195775 1990-2013
elche Elche, Spain 38.27000 -0.690000 2004-2013
esk Eskdalemuir 55.31530 -3.206110 1998-2013
gibraltar Gibraltar 36.13400 -5.347000 2005-2010
glaz Glazebury 53.46008 -2.472056 1998-2013
groningen Groningen 53.40000 6.350000 2007-2013
har Harwell 51.57108 -1.325283 1988-2013
hk Hong Kong 22.29000 114.170000 1998-2013
hm High Muffles 54.33500 -0.808600 1988-2013
kuwait Kuwait City 29.36700 47.967000 2008-2013
lb Ladybower 53.40337 -1.752006 1988-2013
london Central London 51.50000 -0.100000 1990-2013
lh Lullington Heath 50.79370 0.181250 1988-2013
ln Lough Navar 54.43951 -7.900328 1988-2013
mh Mace Head 53.33000 -9.900000 1988-2013
ny-alesund Ny-Alesund, Norway 78.91763 11.894653 2009-2013
oslo Oslo 59.90000 10.750000 2010-2013
paris Paris, France 48.86200 2.339000 2000-2013
roch Rochester Stoke 51.45617 0.634889 1988-2013
rotterdam Rotterdam 51.91660 4.475000 2010-2013
saopaulo Sao Paulo -23.55000 -46.640000 2000-2013
sib Sibton 52.29440 1.463970 1988-2013
sv Strath Vaich 57.73446 -4.776583 1988-2013
wuhan Wuhan, China 30.58300 114.280000 2008-2013
yw Yarner Wood 50.59760 -3.716510 1988-2013
year
Year or years to import. To import a sequence of years from
1990 to 2000 use year = 1990:2000. To import several specific years
use year = c(1990, 1995, 2000) for example.
local
File path to .RData trajectory files run by user and
not stored on the Ricardo web server. These files would have been
generated from the Hysplit trajectory code shown in the appendix
of the openair manual. An example would be local =
'c:/users/david/TrajFiles/'.
progress
Show a progress bar when many receptors/years are being
imported? Defaults to TRUE.
Details
This function imports pre-calculated back trajectories using the HYSPLIT
trajectory model (Hybrid Single Particle Lagrangian Integrated Trajectory
Model. Back trajectories provide some very useful information for air quality
data analysis. However, while they are commonly calculated by researchers it
is generally difficult for them to be calculated on a routine basis and used
easily. In addition, the availability of back trajectories over several years
can be very useful, but again difficult to calculate.
Trajectories are run at 3-hour intervals and stored in yearly files (see
below). The trajectories are started at ground-level (10m) and propagated
backwards in time.
These trajectories have been calculated using the Global NOAA-NCEP/NCAR
reanalysis data archives. The global data are on a latitude-longitude grid
(2.5 degree). Note that there are many different meteorological data sets
that can be used to run HYSPLIT e.g. including ECMWF data. However, in order
to make it practicable to run and store trajectories for many years and
sites, the NOAA-NCEP/NCAR reanalysis data is most useful. In addition, these
archives are available for use widely, which is not the case for many other
data sets e.g. ECMWF. HYSPLIT calculated trajectories based on archive data
may be distributed without permission. For those wanting, for example, to
consider higher resolution meteorological data sets it may be better to run
the trajectories separately.
We are extremely grateful to NOAA for making HYSPLIT available to produce
back trajectories in an open way. We ask that you cite HYSPLIT if used in
published work.
Users can supply their own trajectory files to plot in openair. These files
must have the following fields: date, lat, lon and hour.inc (see details
below).
The files consist of the following information:
- date
This is the arrival point time and is repeated the
number of times equal to the length of the back trajectory — typically 96
hours (except early on in the file). The format is POSIXct. It is this
field that should be used to link with air quality data. See example below.
- receptor
Receptor number, currently only 1.
- year
The year
- month
Month 1-12
- day
Day of the month 1-31
- hour
Hour
of the day 0-23 GMT
- hour.inc
Number of hours back in time e.g. 0 to
-96.
- lat
Latitude in decimal format.
- lon
Longitude in
decimal format.
- height
Height of trajectory (m).
- pressure
Pressure of trajectory (kPa).
Value
Returns a data frame with pre-calculated back trajectories.
Note
The trajectories were run using the February 2011 HYSPLIT model.
The function is primarily written to investigate a single
site at a time for a single year. The trajectory files are quite
large and care should be exercised when importing several years and/or sites.
Author(s)
David Carslaw
See Also
Other import functions:
importADMS(),
importAURN(),
importEurope(),
importKCL(),
importMeta(),
importUKAQ()
Other trajectory analysis functions:
trajCluster(),
trajLevel(),
trajPlot()
Examples
## import trajectory data for London in 2009
## Not run: mytraj <- importTraj(site = "london", year = 2009)
## combine with measurements
## Not run: theData <- importAURN(site = "kc1", year = 2009)
mytraj <- merge(mytraj, theData, by = "date")
## End(Not run)
openair documentation built on May 29, 2024, 11:07 a.m.
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| importTraj | R Documentation |
Import pre-calculated HYSPLIT 96-hour back trajectories
Description
Function to import pre-calculated back trajectories using the NOAA HYSPLIT
model. The trajectories have been calculated for a select range of locations
which will expand in time. They cover the last 20 years or so and can be used
together with other openair functions.
Usage
importTraj(site = "london", year = 2009, local = NA, progress = TRUE)
Arguments
site |
Site code of the network site to import e.g. "london". Only one site can be imported at a time. The following sites are typically available from 2000-2012, although some UK ozone sites go back to 1988 (code, location, lat, lon, year):
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
year |
Year or years to import. To import a sequence of years from
1990 to 2000 use | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
local |
File path to .RData trajectory files run by user and
not stored on the Ricardo web server. These files would have been
generated from the Hysplit trajectory code shown in the appendix
of the openair manual. An example would be | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
progress |
Show a progress bar when many receptors/years are being
imported? Defaults to |
Details
This function imports pre-calculated back trajectories using the HYSPLIT trajectory model (Hybrid Single Particle Lagrangian Integrated Trajectory Model. Back trajectories provide some very useful information for air quality data analysis. However, while they are commonly calculated by researchers it is generally difficult for them to be calculated on a routine basis and used easily. In addition, the availability of back trajectories over several years can be very useful, but again difficult to calculate.
Trajectories are run at 3-hour intervals and stored in yearly files (see below). The trajectories are started at ground-level (10m) and propagated backwards in time.
These trajectories have been calculated using the Global NOAA-NCEP/NCAR reanalysis data archives. The global data are on a latitude-longitude grid (2.5 degree). Note that there are many different meteorological data sets that can be used to run HYSPLIT e.g. including ECMWF data. However, in order to make it practicable to run and store trajectories for many years and sites, the NOAA-NCEP/NCAR reanalysis data is most useful. In addition, these archives are available for use widely, which is not the case for many other data sets e.g. ECMWF. HYSPLIT calculated trajectories based on archive data may be distributed without permission. For those wanting, for example, to consider higher resolution meteorological data sets it may be better to run the trajectories separately.
We are extremely grateful to NOAA for making HYSPLIT available to produce back trajectories in an open way. We ask that you cite HYSPLIT if used in published work.
Users can supply their own trajectory files to plot in openair. These files must have the following fields: date, lat, lon and hour.inc (see details below).
The files consist of the following information:
- date
This is the arrival point time and is repeated the number of times equal to the length of the back trajectory — typically 96 hours (except early on in the file). The format is
POSIXct. It is this field that should be used to link with air quality data. See example below.- receptor
Receptor number, currently only 1.
- year
The year
- month
Month 1-12
- day
Day of the month 1-31
- hour
Hour of the day 0-23 GMT
- hour.inc
Number of hours back in time e.g. 0 to -96.
- lat
Latitude in decimal format.
- lon
Longitude in decimal format.
- height
Height of trajectory (m).
- pressure
Pressure of trajectory (kPa).
Value
Returns a data frame with pre-calculated back trajectories.
Note
The trajectories were run using the February 2011 HYSPLIT model. The function is primarily written to investigate a single site at a time for a single year. The trajectory files are quite large and care should be exercised when importing several years and/or sites.
Author(s)
David Carslaw
See Also
Other import functions:
importADMS(),
importAURN(),
importEurope(),
importKCL(),
importMeta(),
importUKAQ()
Other trajectory analysis functions:
trajCluster(),
trajLevel(),
trajPlot()
Examples
## import trajectory data for London in 2009
## Not run: mytraj <- importTraj(site = "london", year = 2009)
## combine with measurements
## Not run: theData <- importAURN(site = "kc1", year = 2009)
mytraj <- merge(mytraj, theData, by = "date")
## End(Not run)
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