| Type: | Package |
| Title: | Computation and Visualization of Energetic and Vortical Atmospheric Quantities |
| Version: | 0.1.0 |
| Date: | 2022-09-02 |
| Maintainer: | Laura Mack <laum52@zedat.fu-berlin.de> |
| Description: | Energy-Vorticity theory (EVT) is the fundamental theory to describe processes in the atmosphere by combining conserved quantities from hydrodynamics and thermodynamics. The package 'meteoEVT' provides functions to calculate many energetic and vortical quantities, like potential vorticity, Bernoulli function and dynamic state index (DSI) [e.g. Weber and Nevir, 2008, <doi:10.1111/j.1600-0870.2007.00272.x>], for given gridded data, like ERA5 reanalyses. These quantities can be studied directly or can be used for many applications in meteorology, e.g., the objective identification of atmospheric fronts. For this purpose, separate function are provided that allow the detection of fronts based on the thermic front parameter [Hewson, 1998, <doi:10.1017/S1350482798000553>], the F diagnostic [Parfitt et al., 2017, <doi:10.1002/2017GL073662>] and the DSI [Mack et al., 2022, <doi:10.48550/arXiv.2208.11438>]. |
| Author: | Laura Mack [aut, cre] |
| Imports: | grDevices, graphics, purrr, ncdf4 |
| License: | GPL-2 | GPL-3 [expanded from: GPL (≥ 2)] |
| URL: | https://github.com/noctiluc3nt/meteoEVT |
| Encoding: | UTF-8 |
| RoxygenNote: | 7.2.0 |
| NeedsCompilation: | no |
| Packaged: | 2022-09-02 19:21:57 UTC; polarfuchs |
| Repository: | CRAN |
| Date/Publication: | 2022-09-05 08:30:02 UTC |
Introduction
Description
Energy-Vorticity theory (EVT) is the fundamental theory to describe processes in the atmosphere by combining conserved quantities from hydrodynamics and thermodynamics. The package 'meteoEVT' provides functions to calculate many energetic and vortical quantities, like potential vorticity, Bernoulli function and dynamic state index (DSI) (Weber and Nevir, 2008), for given gridded data, like ERA5 reanalyses. These quantities can be studied directly or can be used for many applications in meteorology, e.g., the objective identification of atmospheric fronts. For this purpose, separate function are provided that allow the detection of fronts based on the thermic front parameter (Hewson, 1998), the F diagnostic (Parfitt et al., 2017) and the DSI (Mack et al., 2022).
Details
Phenomenons in the Earth's atmosphere, like tropical hurricanes or extratropical cyclones, can adequately be chararcterized by a combination of energetic and vortical quantities. These quantities can also be used for a consistent theoretical description of these phenomenons. This package provides functions to calculate Bernoulli function, vorticity, enstrophy, helicity, Lamb vector and potential vorticity based on given gridded data sets. Addiotionally, by using energy-vortex theory an adiabatic, stationary and invisicid basic state of the Earth's atmosphere can be derived, which is itself a solution of the primitive equations. The derivation from this basic state is given by the dynamic state index (DSI), which can be used for the study of, e.g., cyclones and fronts. Recently, the DSI was used to identify atmospheric fronts objectively from reanalysis data and thereby provides an alternative way for front detection. For this purpose, this package provides funtions to calculate the DSI and use it to identify atmospheric fronts. This method can be compared with state-of-the-art front identification methods based on the thermic front parameter or the F diagnostic.
References
Weber, T. and Névir, P. (2008). Storm tracks and cyclone development using the theoretical concept of the Dynamic State Index (DSI). Tellus A, 60(1):1–10, doi:10.1111/j.1600-0870.2007.00272.x.
Parfitt, R., Czaja, A., and Seo, H. (2017). A simple diagnostic for the detection of atmospheric fronts. Geophys. Res. Lett., 44:4351–4358, doi:10.1002/2017GL073662.
Hewson, T. D. (1998). Objective fronts. Meteorol. Appl., 5:37–65, doi:10.1017/S1350482798000553.
Mack, L., Rudolph, A. and Névir, P. (2022). Identifying atmospheric fronts based on diabatic processes using the dynamic state index (DSI), arXiv:2208.11438.
R
Description
ideal gas constant [J/(mol*K)]
Usage
R()
Rd
Description
specific gas constant for dry air [J/(kg*K)]
Usage
Rd()
Rv
Description
specific gas constant for water vapor [J/(kg*K)]
Usage
Rv()
Bernoulli function
Description
Calculates the Bernoulli function, i.e. total energy density, as sum of potential, kinetic and thermal energy density
Usage
calc_bernoulli(t_fld, u_fld, v_fld, w_fld, phi_fld)
Arguments
t_fld |
temperature field [K] |
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
phi_fld |
geopotential height [gpm] |
Value
Bernoulli function field [m^2/s^2]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
bernoulli=calc_bernoulli(data$temp,data$u,data$v,data$w,data$z)
Density
Description
Calculates the density of an ideal fluid
Usage
calc_density(t_fld, lev_p)
Arguments
t_fld |
temperature field [K] |
lev_p |
vector containing pressure levels [Pa] |
Value
density [kg/m^3]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
density=calc_density(data$temp,data$lev)
Dynamic State Index (DSI)
Description
Calculates the dynamic state index DSI
Usage
calc_dsi(
t_fld,
u_fld,
v_fld,
w_fld,
phi_fld,
lev_p,
lat = NULL,
dx = 0.25,
dy = 0.25,
zvort_only = FALSE,
relative = FALSE,
pv_fld = NULL,
mode = "lonlat"
)
Arguments
t_fld |
temperature field [K] |
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
phi_fld |
geopotential height [gpm] |
lev_p |
vector containing pressure levels [Pa] |
lat |
vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
zvort_only |
logical, TRUE: if only the vertical vorticity (zvort) should be calculated, FALSE: for the whole vorticity vector, default: FALSE |
relative |
logical, TRUE: only relative vorticity, FALSE: whole (absolute) vorticity, default: FALSE |
pv_fld |
optional pv field (if e.g., PV is directly taken from ERA5 and not calculated separately) |
mode |
use 'lonlat' if the data is given on a lon-lat-grid or 'cartesian' if the data is given on an equidistant cartesian grid |
Value
dynamic state index [K^2*m^4/(kg^2*s^3)]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
dsi=calc_dsi(data$temp,data$u,data$v,data$w,data$z,lev_p=data$lev,lat=data$lat)
Enstrophy density
Description
Calculates the enstrophy density (vorticity squared) either in 2d or 3d
Usage
calc_enstrophy(
u_fld,
v_fld,
w_fld = NULL,
lev_p,
lat = NULL,
dx = 0.25,
dy = 0.25,
zvort_only = TRUE,
relative = TRUE,
zvort_fld = NULL,
mode = "lonlat"
)
Arguments
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
lev_p |
vector containing pressure levels [Pa] |
lat |
vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
zvort_only |
logical, TRUE: if only 2d enstrophy (based on z-vorticity) should be calculated, FALSE: for 3d enstrophy (based on 3d vorticity), default: TRUE |
relative |
logical, TRUE: only relative vorticity, FALSE: whole (absolute) vorticity should be used for calculation of enstrophy, default: TRUE |
zvort_fld |
optional zvort field (if e.g., zvort is directly taken from ERA5 and not calculated separately) |
mode |
use 'lonlat' if the data is given on a lon-lat-grid or 'cartesian' if the data is given on an equidistant cartesian grid |
Value
enstrophy density field [1/s^2]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
#3d enstropy
ens3d=calc_enstrophy(data$u,data$v,data$w,data$lev,lat=data$lat)
#2d enstropy as scalar
ens2d=calc_enstrophy(data$u,data$v,lev_p=data$lev,lat=data$lat,zvort_only=TRUE)
F diagnostic
Description
Calculates the F diagnostic
Usage
calc_fdiag(
t_fld,
u_fld,
v_fld,
w_fld,
lev_p,
lat = NULL,
dx = 0.25,
dy = 0.25,
mode = "lonlat"
)
Arguments
t_fld |
temperature field [K] |
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
lev_p |
vector containing pressure levels [Pa] |
lat |
only for lonlat mode: vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
mode |
the horizontal coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
Value
F diagnostic (dimensionless)
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
fdiag=calc_fdiag(data$temp,data$u,data$v,data$w,data$lev,data$lat)
Petterssen Frontogenesis Function
Description
Calculates the Petterssen frontogenesis function based on the potential temperature
Usage
calc_frontogenesis(
t_fld,
u_fld,
v_fld,
w_fld,
lev_p,
mode = "lonlat",
lat = NULL,
dx = 0.25,
dy = 0.25
)
Arguments
t_fld |
temperature field [K] |
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
lev_p |
vector containing pressure levels [Pa] |
mode |
the coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
lat |
only for lonlat mode: vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
Value
Petterssen Frontogenesis Function
Helicity density
Description
Calculates the helicity density (scalar product of wind vector and vorticity vector) either for the whole vector (3d) or only for the vertical component (updraft helicity)
Usage
calc_helicity(
u_fld,
v_fld,
w_fld,
lev_p,
lat = NULL,
dx = 0.25,
dy = 0.25,
vert_only = FALSE,
relative = TRUE,
zvort_fld = NULL,
mode = "lonlat"
)
Arguments
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
lev_p |
vector containing pressure levels [Pa] |
lat |
vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
vert_only |
logical, TRUE: if only the updraft helicity w*zeta (based on z-vorticity) should be calculated, FALSE: for 3d helicity (based on 3d vorticity), default: FALSE |
relative |
logical, TRUE: only relative vorticity, FALSE: whole (absolute) vorticity should be used for calculation of enstrophy, default: TRUE |
zvort_fld |
optional zvort field (if e.g., zvort is directly taken from ERA5 and not calculated separately) |
mode |
use 'lonlat' if the data is given on a lon-lat-grid or 'cartesian' if the data is given on an equidistant cartesian grid |
Value
helicity density field [m/s^2]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
#3d helicity
hel=calc_helicity(data$u,data$v,data$w,data$lev,lat=data$lat)
#updraft helicity
up_hel=calc_helicity(data$u,data$v,data$w,data$lev,lat=data$lat,vert_only=TRUE)
Lamb vector (sometimes called vortex energy)
Description
Calculates the Lamb vector (cross product of wind vector and vorticity vector)
Usage
calc_lamb(
u_fld,
v_fld,
w_fld,
lev_p,
lat = NULL,
dx = 0.25,
dy = 0.25,
relative = TRUE,
zvort_fld = NULL,
mode = "lonlat"
)
Arguments
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
lev_p |
vector containing pressure levels [Pa] |
lat |
vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
relative |
logical, TRUE: only relative vorticity, FALSE: whole (absolute) vorticity should be used for calculation of enstrophy, default: TRUE |
zvort_fld |
optional zvort field (if e.g., zvort is directly taken from ERA5 and not calculated separately) |
mode |
use 'lonlat' if the data is given on a lon-lat-grid or 'cartesian' if the data is given on an equidistant cartesian grid |
Value
lamb vector [m/s^2]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
lamb=calc_lamb(data$u,data$v,data$w,data$lev,lat=data$lat)
Potential Vorticity (PV)
Description
Calculates the potential vorticity
Usage
calc_pv(
t_fld,
u_fld,
v_fld,
w_fld,
lev_p,
lat = NULL,
dx = 0.25,
dy = 0.25,
zvort_only = FALSE,
relative = FALSE,
zvort_fld = NULL,
mode = "lonlat"
)
Arguments
t_fld |
temperature field [K] |
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
lev_p |
vector containing pressure levels [Pa] |
lat |
vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
zvort_only |
logical, TRUE: if only the vertical vorticity (zvort) should be calculated, FALSE: for the whole vorticity vector, default: FALSE |
relative |
logical, TRUE: only relative vorticity, FALSE: whole (absolute) vorticity, default: FALSE |
zvort_fld |
optional zvort field (if e.g., zvort is directly taken from ERA5 and not calculated separately) |
mode |
use 'lonlat' if the data is given on a lon-lat-grid or 'cartesian' if the data is given on an equidistant cartesian grid |
Value
potential vorticity field [K*m^2/(kg*s)]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
#PV based on all three components
pv=calc_pv(data$temp,data$u,data$v,data$w,data$lev,lat=data$lat)
#PV only based on vertical component
pv_vert=calc_pv(data$temp,data$u,data$v,data$w,lev_p=data$lev,lat=data$lat,zvort_only=TRUE)
Thermic Front Parameter (TFP)
Description
Calculates the thermic front parameter based on the potential temperature
Usage
calc_tfp(t_fld, lev_p, lat = NULL, dx = 0.25, dy = 0.25, mode = "lonlat")
Arguments
t_fld |
temperature field [K] |
lev_p |
vector containing pressure levels [Pa] |
lat |
only for lonlat mode: vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
mode |
the horizontal coordinate system, options are 'lonlat' for a longitude-latitude-grid (default), or 'cartesian' for an equidistant cartesian grid |
Value
thermic front parameter [K/m^2]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
tfp=calc_tfp(data$temp,data$lev,data$lat)
Potential temperature
Description
Calculates the potential temperature
Usage
calc_theta(t_fld, lev_p)
Arguments
t_fld |
temperature field [K] |
lev_p |
vector containing pressure levels [Pa] |
Value
density [kg/m^3]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
theta=calc_theta(data$temp,data$lev)
Vorticity
Description
Calculates the vorticity
Usage
calc_vorticity(
u_fld,
v_fld,
w_fld,
lev_p,
lat = NULL,
dx = 0.25,
dy = 0.25,
zvort_only = FALSE,
relative = FALSE,
zvort_fld = NULL,
mode = "lonlat"
)
Arguments
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
lev_p |
vector containing pressure levels [Pa] |
lat |
vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
zvort_only |
logical, TRUE: if only the vertical vorticity (zvort) should be calculated, FALSE: for the whole vorticity vector, default: FALSE |
relative |
logical, TRUE: only relative vorticity, FALSE: whole (absolute) vorticity, default: FALSE |
zvort_fld |
optional zvort field (if e.g., zvort is directly taken from ERA5 and not calculated separately) |
mode |
use 'lonlat' if the data is given on a lon-lat-grid or 'cartesian' if the data is given on an equidistant cartesian grid |
Value
vorticity field [1/s]
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
#3d vorticity
xi=calc_vorticity(data$u,data$v,data$w,data$lev,lat=data$lat)
#z-vorticity as scalar
zeta=calc_vorticity(data$u,data$v,data$w,data$lev,lat=data$lat,zvort_only=TRUE)
cp
Description
heat capacity for constant pressure [J/(kg*K)]
Usage
cp()
cross product
Description
Calculates the cross product of two given 3d vector fields
Usage
crossprod(fld1, fld2)
Arguments
fld1 |
field 1 with dimensions (lon,lat,p,3) |
fld2 |
field 2 with dimensions (lon,lat,p,3) |
Value
field containing the cross product
df_dp
Description
Calculates the p derivative (pressure system) using central differences
Usage
df_dp(fld, plev = 5000)
Arguments
fld |
field with dimensions (lon,lat,p) |
plev |
a scalar containing the p resolution (if equidistant) or a vector containing pressure levels in Pa (for non-equidistant) |
Value
field containing the partial derivative w.r.t. p
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
theta=calc_theta(data$temp,data$lev)
dtheta_dp=df_dp(theta)
df_dx
Description
Calculates the x derivative using central differences (for lonlat-grid or cartesian grid)
Usage
df_dx(fld, lat = NULL, dx = 0.25, mode = "lonlat")
Arguments
fld |
field with dimensions (lon,lat,p) |
lat |
only for lonlat mode: vector containing latitude |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
mode |
the coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
Value
field containing the partial derivative w.r.t. x
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
theta=calc_theta(data$temp,data$lev)
dtheta_dx=df_dx(theta,data$lat)
df_dy
Description
Calculates the y derivative using central differences
Usage
df_dy(fld, dy = 0.25, mode = "lonlat")
Arguments
fld |
with dimensions (lon,lat,p) |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
mode |
the coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
Value
field containing the partial derivative w.r.t. y
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
theta=calc_theta(data$temp,data$lev)
dtheta_dy=df_dy(theta,dy=0.25)
df_dz
Description
Calculates the z derivative
Usage
df_dz(fld, rho, plev = 5000)
Arguments
fld |
field with dimensions (lon,lat,p) |
rho |
field with dimensions (lon,lat,p) for density or a scalar rho (for constant density) |
plev |
a scalar containing the p resolution (if equidistant) or a vector containing pressure levels in Pa (for non-equidistant) |
Value
field containing the partial derivative w.r.t. z
divergence
Description
Calculates the divergence of a vector field
Usage
div(
fld,
lat = NULL,
d = 3,
system = "p",
rho = NULL,
dx = 0.25,
dy = 0.25,
plev = 5000,
mode = "lonlat"
)
Arguments
fld |
field with dimensions (lon,lat,p,d) |
lat |
vector containing latitude (only for |
d |
scalar for dimension (use d=2 for horizontal gradient and d=3 for 3d-gradient) |
system |
for type of coordinate system (use 'p' for pressure system and 'z' for height system) |
rho |
field with dimensions (lon,lat,p) for density or a scalar rho (for constant density) |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
plev |
a scalar containing the p resolution (if equidistant) or a vector containing pressure levels in Pa (for non-equidistant) |
mode |
the coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
Value
field containing the divergence of fld
Plotting a xy domain with custom boundaries, colour paletts and optional world map
Description
Plotting a xy domain with custom boundaries, colour paletts and optional world map
Usage
fill_horiz(
x,
y,
fld,
levels = 1:100,
main = "",
worldmap = TRUE,
legend_loc = "topright",
legend_title = "",
legend_only = FALSE,
Lab = NULL,
...
)
Arguments
x |
array containing x-axis values (e.g. longitude) |
y |
array containing y-axis values (e.g. latitude) |
fld |
field (which should be plotted) with dimensions (x,y) |
levels |
levels for colour bar |
main |
character containing main title of the plot |
worldmap |
should the world map contours be plotted (default TRUE) |
legend_loc |
location of legend |
legend_title |
character containing legend title |
legend_only |
logical TRUE only legend should be pltted, or FALSE everything should be plotted (default) |
Lab |
lab palette from type colorRampPalette |
... |
additional graphic parameters |
Value
no return
Front Identification und Statistics
Description
Calculates frontal zones based on a chosen method (TFP, F diagnostic, DSI) and provides statistics of the distribution of meteorological quantities inside the determined frontak zones.
Usage
frontid(
t_fld,
u_fld = NULL,
v_fld = NULL,
w_fld = NULL,
phi_fld = NULL,
lev_p,
lat = NULL,
method = "tfp",
threshold = 2 * 10^-10,
dx = 0.25,
dy = 0.25,
fronts_only = FALSE,
mode = "lonlat"
)
Arguments
t_fld |
temperature field [K] |
u_fld |
zonal velocity field [m/s] |
v_fld |
meridional velocity field [m/s] |
w_fld |
vertical velocity field [m/s] |
phi_fld |
geopotential height [gpm] |
lev_p |
vector containing pressure levels [Pa] |
lat |
only for lonlat mode: vector containing latitude |
method |
character containing the method, use |
threshold |
scalar containing a suitable threshold (e.g., 2*10^-10 for TFP method, 1 or for F diagnostic, 10^-16 for DSI method) |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
fronts_only |
if you only want to calculate the frontal regions and not their properties (default FALSE) |
mode |
the horizontal coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
Value
list containing the used method and used threshold, field with logicals containing the detected frontal zones and numerics of temperature, u-wind, v-wind, w-wind, geopotential, vorticity, PV and DSI inside the determined frontal zones
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
#front identification using the thermic front parameter (example without front statistic)
tfp_fronts=frontid(data$temp,lev_p=data$lev,lat=data$lat,fronts_only=TRUE)
#front identification using F diagnostic (example with front statistic)
f_fronts=frontid(data$temp,data$u,data$v,data$w,data$z,lev_p=data$lev,lat=data$lat,
method='f',threshold=2,fronts_only=FALSE)
#front identification using the dynamic state index (example with statistic)
dsi_fronts=frontid(data$temp,data$u,data$v,data$w,data$z,lev_p=data$lev,lat=data$lat,
method='dsi',threshold=4*10^-16,fronts_only=FALSE)
g
Description
gravitional accelaration [m/s^2]
Usage
g()
gradient of a scalar field
Description
Calculates the gradient
Usage
grad(
fld,
lat = NULL,
d = 3,
system = "p",
rho = NULL,
dx = 0.25,
dy = 0.25,
plev = 5000,
mode = "lonlat"
)
Arguments
fld |
field with dimensions (lon,lat,p) |
lat |
vector containing latitude |
d |
scalar for dimension (use d=2 for horizontal gradient and d=3 for 3d-gradient) |
system |
for type of coordinate system (use 'p' for pressure system and 'z' for height system) |
rho |
field with dimensions (lon,lat,p) for density or a scalar rho (for constant density) |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
plev |
a scalar containing the p resolution (if equidistant) or a vector containing pressure levels in Pa (for non-equidistant) |
mode |
the coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
Value
field containing the gradient with dimension (lon,lat,p,d)
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
theta=calc_theta(data$temp,data$lev)
theta_grad=grad(theta,data$lat)
Jacobian matrix and determinant
Description
Calculates the Jacobian matrix and Jacobian determinant for 2 or 3 given scalar fields
Usage
jacobian(
fld1,
fld2,
fld3 = NULL,
lat = NULL,
d = 3,
system = "p",
rho = NULL,
dx = 0.25,
dy = 0.25,
plev = 5000,
mode = "lonlat"
)
Arguments
fld1 |
field 1 with dimensions (lon,lat,p) |
fld2 |
field 2 with dimensions (lon,lat,p) |
fld3 |
field 3 with dimensions (lon,lat,p) |
lat |
vector containing latitude |
d |
scalar for dimension (use d=2 for 2 input fields and d=3 for 3 inpt fields) |
system |
for type of coordinate system (use 'p' for pressure system and 'z' for height system) |
rho |
field with dimensions (lon,lat,p) for density or a scalar rho (for constant density) |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
plev |
a scalar containing the p resolution (if equidistant) or a vector containing pressure levels in Pa (for non-equidistant) |
mode |
the coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
Value
list containing Jacobian matrix and determinant
omega
Description
Earth's rotation frequency [1/s]
Usage
omega()
re
Description
Earth's radius [m]
Usage
re()
read in dimensions
Description
: reads dimensions of ERA5 data
Usage
readin_dim(filename)
Arguments
filename |
name of file to read in |
Value
no return
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data_dims = readin_dim(myfile)
read in ERA5 data
Description
: reads ERA5 data
Usage
readin_era5(filename)
Arguments
filename |
name of file to read in |
Value
no return
Examples
myfile=system.file("extdata", "era5_storm-zeynep.nc", package = "meteoEVT")
data = readin_era5(myfile)
rotation
Description
Calculates the rotation of a vector field
Usage
rot(
fld,
lat = NULL,
d = 3,
system = "p",
rho = NULL,
dx = 0.25,
dy = 0.25,
plev = 5000,
mode = "lonlat"
)
Arguments
fld |
with dimensions (lon,lat,p,d) |
lat |
vector containing latitude |
d |
scalar for dimension (use d=2 for horizontal gradient and d=3 for 3d-gradient) |
system |
for type of coordinate system (use 'p' for pressure system and 'z' for height system) |
rho |
field with dimensions (lon,lat,p) for density or a scalar rho (for constant density) |
dx |
x resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
dy |
y resolution in the corresponding unit (e.g. 0.25 degree for ERA5 with |
plev |
a scalar containing the p resolution (if equidistant) or a vector containing pressure levels in Pa (for non-equidistant) |
mode |
the coordinate system, options are lonlat for a longitude-latitude-grid (default), or cartesian for an equidistant cartesian grid |
Value
field containing the divergence of fld
scalar product
Description
Calculates the scalar product of two given fields
Usage
scalarprod(fld1, fld2)
Arguments
fld1 |
field 1 with dimensions (lon,lat,p,d) |
fld2 |
field 2 with dimensions (lon,lat,p,d) |
Value
field of the scalar product with dimensions (lon,lat,p)