McIDAS-X User's Guide
Version 2023.1
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UACROSS
Plots
a vertical cross section of upper-air data.
Format
UACROSS loc1
. . locN [keywords]
Parameters
loc1
. . locN |
two
or more locations to include in the cross section; each location can
be specified as a 4-character station ID (e.g., KINL), a 5-digit station
ID number (e.g., 72747), or a latitude/longitude pairing enclosed in
single quotes (e.g.,'48.5 93.3' or '48:30:10 93:18:40'); see the Remarks
for information about how the specified locations and other keywords
are used to select and plot datapoints in the cross section |
Data Selection Keywords
(Point and Grid)
DATaset= |
point
or grid dataset(s) to use in the cross section; use the mand sig format
for point datasets and grid_dataset format for grid datasets;
the default is for point datasets as described below so you must specify
this keyword to use a grid dataset; see the Remarks for information about
the differences in datapoint selection with point data and grid data |
|
mand
sig |
point
dataset(s) containing the mandatory- and significant-level data to use
in the cross section; must also specify SIG=YES if you want significant
levels included with the mandatory levels; currently only IRAB/IRSG and
RAOB/RSIG schema point datasets can be used (mand default=RTPTSRC/UPPERMAND; sig default=RTPTSRC/UPPERSIG
if mand =RTPTSRC/UPPERMAND and SIG=YES, otherwise sig default=NONE) |
|
grid_dataset |
grid
dataset containing the grids to use in the cross section |
DAY= |
date
of grids or observation date in point file; valid formats include YYYYDDD,
YYYY/MM/DD and DD/MON/YYYY where YYYY, DDD, MM and DD are integers and
MON is 3 or more letters, e.g., JAN or JANUARY (default=current for point
data; no default for grids) |
TIMe= |
time
of grids or observation time in point file (for point data, default=0
if current time is between 0 UTC and 11:59 UTC, otherwise default=12;
no default for grids) |
MODe= |
I |
interactive
mode that uses the navigation of the current frame and the mouse to select
locations for the cross section; you can select between 2 and 13 locations;
see the Remarks for information about how the selected locations and
other keywords are used to find and plot datapoints in the cross section;
MODE=I is valid only if locations are not specified in the loc1 .
. locN parameters (default=I if no locations are specified in loc1
. . locN) |
|
N |
non-interactive
mode where the cross section's locations are selected with the loc1
. . locN parameters (default=N if locations are specified in loc1
. . locN) |
CORridor= |
YES size[units]
use corridor(s) of the specified size to select datapoints for
the cross section; a corridor is a rectangular region with a line running
down the middle that connects the beginning and ending locations and
a width equal to 2 times the size specified in this keyword;
use size and/or the EXCLUDE or INCREMENT keyword to increase
or decrease the number of datapoints in the cross section; run command
CU LIST to list the valid units; see the Remarks for additional
information about corridors |
|
|
NO size [units]
do not use corridor(s); thus only the 3+ locations specified
in loc1 . . locN or located with MODE=I are included in the
cross section; for CORRIDOR=NO the size value and units specify
the maximum radius from each location (selected with MODE=I or specified
in loc1 . . locN) to use to find an endpoint; the closest datapoint
within the radius is selected as the endpoint; if no datapoints are within
the radius, UACROSS fails (default=YES 250[KM] if two locations are selected
with MODE=I or are specified in loc1 . . locN; default=NO 250[KM]
if 3 or more locations are selected or specified) |
|
PRAnge= |
min
max |
pressure
levels, in mb, at top and bottom of diagram, respectively (default=100
1050) |
Point-Only Data Selection Keywords
EXClude= |
stn1
. . stnN |
stations
to exclude from the cross section; up to 8 stations may be excluded;
each station can be specified as a 4-character station ID (e.g., KINL)
or a 5-digit station ID number (e.g., 72747); this keyword is useful
for re-running commands that select more stations than desired and/or
include questionable data |
SIG= |
NO |
do
not include data from significant-level dataset specified in DATASET
keyword; use only its mandatory-level dataset (default) |
|
YES |
include
data from significant-level dataset specified in DATASET keyword |
Grid-Only Data Selection Keywords
FDAy= |
forecast
day of grids to use in cross section; calculated by adding a grid's fhour
to its day and time, e.g., a grid with day=2000300, time=12 and fhour=72
has fday=2000303; use with FTIME to select a specific forecast day and
time; you cannot use FDAY with the FHOUR keyword |
FHOur= |
forecast
hour of grids to use in cross section; you cannot use FHOUR with the
FDAY or FTIME keyword |
FTIme= |
forecast
time of grids to use in cross section; calculated by adding a grid's
fhour to its time, e.g., a grid with time=12 and fhour=18 has ftime=6
on the following day; use with FDAY to select a specific forecast time
and day; you cannot use FTIME with the FHOUR keyword |
GPRo= |
projection
of grids to use in cross section, e.g., MERC, PS, LAMB, EQUI |
INCrement= |
row
col |
grid
point sampling increment for rows and columns; use this keyword and the
CORRIDOR keyword to increase or decrease the number of grid points that
can be used as datapoints in a cross section corridor; see the Remarks
(row default=5; col default=row) |
SRC= |
source
of grids to use in cross section, e.g., ETA, GFS, MDX |
Parameter Selection and Display Keywords
PARam= |
par1 [unit1] .
. parN [unitN]
list of up to 10 parameters to plot and their output units (default=THA[K]);
the valid parameters are DIR, MIX, P, RH, SPD, SPDE, SPDN, SPDS, SPDZ,
T, TD, TE, THA, THE, THW, TV, TW, U, V, WINDB, Z; see table in Remarks
for parameter descriptions, their default units, and their defaults for
the CINT, COLOR, DASH, LINT, LSIZE, and SMOOTH keywords |
|
CINt= |
c1
. . cN |
contour
interval for each PARAMeter; specify 0 to let UACROSS compute a reasonable
interval, a value greater than zero to select your own value, or the
name of a string that contains up to 64 values (default=value specified
for corresponding parameter in UACROSS.* text
file - see table and paragraphs before and after it in the Remarks) |
COLor= |
c1
. . cN |
graphics
color level for each PARAMeter (default=value specified for corresponding
parameter in UACROSS.* text
file - see table and paragraphs before it in Remarks) |
DASh= |
d1
. . dN |
contour
dash mode for each PARAMeter; specify one of the following values for
each PARAMeter:
ALL - dash all contours
NONE - do not dash contours
NEG - dash negative contours only
POS - dash positive contours only
(default=value specified for corresponding parameter in UACROSS.* text
file - see table and paragraphs before it in Remarks) |
LINt= |
l1
. . lN |
contour
label interval for each PARAMeter; the value must be greater than 0;
the value 1 means label every contour, 2 means label every other contour,
etc. (default=value specified for corresponding parameter in UACROSS.* text
file - see table and paragraphs before it in Remarks) |
LSIze= |
l1
. . lN |
contour
label height, in pixels, for each PARAMeter (default=value specified
for corresponding parameter in UACROSS.* text
file - see table and paragraphs before it in Remarks) |
SMOoth= |
s1
. . sN |
contour
smoothing factor for each PARAMeter; the range is 3-50; larger numbers
produce smoother contours (default=value specified for corresponding
parameter in UACROSS.* text
file - see table and paragraphs before it in Remarks) |
Other Output Keywords
EG= |
NO |
do
not erase graphics frame before plotting (default=YES) |
GCOlor= |
bg
land tlab blab datapt p map path
graphics color level of cross section components
(default=8 8 3 X 3 8 1 3), where: |
|
bg |
background
borders, vertical lines and tic marks |
|
land |
land
surface |
|
tlab |
top
label identifying beginning and ending datapoints |
|
blab |
bottom
label identifying plotted parameters; the default color for each parameter's
label is the value specified in the COLOR keyword for that parameter |
|
datapt |
datapoint
labels at bottom of diagram |
|
p |
pressure
labels on left side of diagram |
|
map |
inset
map, when requested with MAP=YES keyword |
|
path |
cross
section path and datapoint markers on map |
|
note:
you can specify 0 to omit (not draw) any component |
IDLabel= |
NUMbers |
display
5-digit ID numbers of plotted stations at bottom of cross section; valid
only with point data (default for point data) |
|
NAMes |
display
4-character IDs of plotted stations at bottom of cross section; valid
only with point data |
|
LALO |
display
latitude/longitude pairings of plotted stations at bottom of cross section;
valid with point or grid data (default for grid data) |
GRA= |
graphic
frame number to display cross section (default=current) |
LABel= |
'text' color
line ele size
text, color, location & size for cross section label, where: |
|
'text' |
label's
text; 80 characters maximum; specify X without quotes for default text
(default=computed) |
|
color |
graphics
color level of label (default=3) |
|
line |
beginning
TV line to write label (default=lower-left corner of frame; line number
depends on frame size) |
|
ele |
beginning
TV element to write label (default=20) |
|
size |
pixel
size of characters drawn (default=8) |
|
note:
if you specify this keyword, the default top and bottom labels (which
identify beginning and ending datapoints, and plotted parameters, respectively)
are not drawn |
LIStinfo= |
YES |
list
detailed station information (ID number, ID name, station name, state,
country, latitude, longitude and elevation) of each station in text frame;
valid only when using point data, i.e, not valid with grids |
|
NO |
do
not list detailed information; list only the ID number (default) |
MAP= |
NO |
do
not draw a map showing the cross section (default) |
|
YES |
draws
a map in the upper-right corner of the frame showing the cross section
location, datapoints, and path as determined by the SPACING keyword |
|
YES 'command'
draws a map using the MAP command specified in 'command'
and draws the cross section datapoints and path as determined by the
SPACING keyword; use this option to override the map domain and/or frame
location that MAP=YES draws; the defaults for the 'command'
are the same as in the MAP command except for the LIN and ELE keywords,
which default to the upper-right corner like the default MAP=YES output
Examples:
1.
MAP=YES 'MAP MID X LALO'
draws a map of the Midwest with lat/lon lines instead of the default
map computed by UACROSS
2.
MAP=YES 'MAP MID X LALO LIN=300 450 ELE=10 210'
draws the same map
but places it in the location specified with the LIN and ELE keywords
instead of the upper-right corner of the frame
|
SPAcing= |
NORMAL |
spaces
datapoints in the diagram using the normalized distances along the cross
section axis; i.e., the distance between datapoints on the diagram is
proportional to the distance between where their lines perpendicular
to the axis intersect the axis; if you also draw a map using the MAP
keyword, the cross section path is drawn along the axis |
|
ACTUAL |
spaces
datapoints in the diagram according to their actual distances from each
other, not the normalized distances along the axis; if you also draw
a map using the MAP keyword, the cross section path is drawn from datapoint
to datapoint, in a zig-zag pattern as defined by the datapoint locations;
this option is not recommended if grid data is used and CORRIDOR=YES
is specified (default=ACTUAL if three or more locations and CORRIDOR=NO
are specified, otherwise default=NORMAL) |
Remarks
UACROSS plots
contoured vertical cross sections of meteorological parameters using point
or grid data. Use the DATASET keyword to specify the point or grid dataset,
and keywords like TIME, DAY and FHOUR and SRC to narrow the search to more
specific data. The cross section requires upper-air data from three or more
datapoints. A datapoint is an observation location in a point file, or a grid
point location in a grid. The datapoints are found using the locations specified
in the loc1 . . locN parameters or the geographic points selected
interactively with the mouse when MODE=I. The six paragraphs below explain
how datapoints are selected and plotted in the cross section.
If you use
point data and specify station IDs in loc1 . . locN, UACROSS uses
the data only at those stations. That is, it will NOT look for data at a nearby
station if the specified station didn't report data. Therefore, UACROSS will
fail if any of the specified stations don't have data at the requested time.
If you use
grid data, or use point data and specify latitude/longitude locations in loc1
. . locN or interactively choose locations with MODE=I, UACROSS selects
the datapoint closest to each location if it's within the size value
in the CORRIDOR keyword. Therefore, the lat/lons specified in loc1 . .
locN or locations chosen with MODE=I do NOT have to exactly match those
of stations in a point file or grid points in a grid.
If you specify
only two locations in loc1 . . locN or select only two locations with
MODE=I, they are used to find the beginning and ending datapoints (endpoints)
of the cross section. The beginning datapoint is plotted on the left end and
the ending datapoint is plotted on the right end of the diagram. Datapoints
within the corridor defined by the endpoints and the size value in
the CORRIDOR keyword are included in the cross section unless they're excluded
by the program because they're too close to another datapoint or are excluded
by the EXCLUDE or INCREMENT keywords.
If you specify
3 to 13 locations in loc1 . . locN and CORRIDOR=YES, or you select
3 to 13 locations with MODE=I and specify CORRIDOR=YES, multiple corridors
are used and the first and second locations are used to find the endpoints
for the first corridor, the second and third locations are used to find the
endpoints for the second corridor, etc. Datapoints within each corridor defined
by its endpoints and the size value in the CORRIDOR keyword are included
in the cross section unless they're excluded by the program because they're
too close to another datapoint or are excluded by the EXCLUDE or INCREMENT
keywords.
If you specify
3 to 13 locations in loc1 . . locN and CORRIDOR=NO, or you select
3 to 13 locations with MODE=I and specify CORRIDOR=NO, corridors are not used,
so only the datapoints for each location are included in the cross section.
The datapoints are plotted from left to right on the cross section.
Although
up to 25 datapoints can be included when CORRIDOR=YES is specified, a more
practical limit is 15 or less. To decrease the number of datapoints, specify
a smaller size value in the CORRIDOR keyword and/or larger row and col values
in the INCREMENT keyword (which is valid only with grid data). For example,
INC=8 6 allows datapoints to be selected only at grid points in every eighth
row and every sixth column within the specified CORRIDOR. Longer and/or wider
corridors often require larger INCREMENT values to keep the number of datapoints
to 15 or less. The most uniform distribution of datapoints along a corridor
is obtained by setting INC=1 and keeping the size value in CORRIDOR
as small as necessary to reject neighboring grid points without excluding the
anchoring endpoints. Use the SPACING keyword to specify how the sounding at
each datapoint is projected onto the cross section.
The default
units and keyword values for each parameter specified in the PARAM keyword
are stored in the text files UACROSS.USER, UACROSS.SITE,
and UACROSS.CORE. The .USER file
overrides the .SITE file, which
overrides the .CORE file. This
order of precedence allows you to define your preferred defaults in your .USER file.
The .CORE file is supplied with
McIDAS-X and should not be modified. To create a .USER or .SITE file,
copy the .CORE file from ~mcidas/data to
your $HOME/mcidas/data directory
(or another MCPATH directory)
and edit the values as needed.
The table
below lists the contents of the UACROSS.CORE file,
which includes the parameters that can be specified in the PARAM keyword, their
default units, and their default values for the CINT, COLOR, DASH, LINT, LSIZE,
and SMOOTH keywords. Default units enclosed in parenthesis cannot be changed.
Otherwise the units can be changed with the PARAM keyword and/or by creating
and modifying a UACROSS.USER or UACROSS.SITE file
as described above. Likewise, the other values can be changed with their corresponding
keywords and/or in UACROSS.USER or UACROSS.SITE.
| |
Default
Values |
|
| Param |
Unit |
CINt |
COLor |
DASh |
LINt |
LSIze |
SMOoth |
Description |
| DIR |
(degrees) |
90 |
1 |
ALL |
1 |
6 |
20 |
wind
direction |
| MIX |
(G/KG) |
2 |
4 |
ALL |
1 |
6 |
20 |
mixing
ratio |
| P |
MB |
50 |
8 |
NONE |
2 |
6 |
20 |
pressure |
| RH |
(%) |
5 |
8 |
NONE |
2 |
6 |
20 |
relative
humidity |
| SPD |
KTS |
5 |
2 |
NONE |
1 |
6 |
20 |
wind
speed |
| SPDE |
KTS |
5 |
2 |
NEG |
1 |
6 |
20 |
enhanced
wind normal to cross section |
| SPDN |
KTS |
5 |
2 |
NEG |
1 |
6 |
40 |
wind
normal to cross section |
| SPDZ |
(1/S) |
5 |
2 |
NEG |
1 |
6 |
20 |
vertical
wind shear |
| T |
C |
5 |
5 |
NEG |
2 |
6 |
20 |
temperature |
| TD |
C |
5 |
4 |
NEG |
2 |
6 |
20 |
dewpoint
temperature |
| TE |
K |
5 |
5 |
NEG |
2 |
6 |
20 |
equivalent
temperature |
| THA |
K |
5 |
5 |
NEG |
2 |
6 |
20 |
potential
temperature |
| THE |
K |
2 |
5 |
NEG |
2 |
6 |
20 |
equivalent
potential temperature |
| THW |
K |
1 |
4 |
NEG |
2 |
6 |
20 |
wet
bulb potential temp. |
| TV |
K |
5 |
5 |
NEG |
2 |
6 |
20 |
virtual
temperature |
| TW |
K |
5 |
4 |
NEG |
2 |
6 |
20 |
wet
bulb temperature |
| U |
KTS |
5 |
2 |
NEG |
2 |
6 |
20 |
easterly
wind component |
| V |
KTS |
5 |
3 |
NEG |
2 |
6 |
20 |
northerly
wind component |
| WINDB |
(barb) |
n/a |
7 |
n/a |
n/a |
12 |
n/a |
windbarb:
flag=25mps(~50kts)
long barb=5mps(~10kts) short barb=2.5mps(~5kts) |
| Z |
M |
2000 |
1 |
NEG |
2 |
6 |
20 |
height
from surface |
The default
contour interval for each parameter is taken from the appropriate UACROSS.* text
file as described above the table. If you change the units of a parameter you
may also want to change the contour interval as the defaults above are usually
appropriate only for the default units. If you specify 0 for the contour interval,
a value is calculated that produces a reasonable number of contours, usually
between 10 and 20. In all cases the values will be adjusted slightly by the
program to the nearest multiple of 1, 5, 10, 50, etc., consistent with the
plot resolution.
Examples
UACROSS
This entry
displays a cross section of potential temperature for locations selected interactively
using the mouse. If two locations are selected, datapoints within a 500 km-wide
corridor with endpoints at the two locations are selected. If three or more
locations are selected, only the datapoint at or closest to (within 250 km)
each location is selected.
UACROSS CORRIDOR=YES 150[MI] MAP=YES
This entry
displays a cross section of potential temperature for locations selected interactively
using the mouse. A 300 mile-wide corridor is computed for each pair of consecutively
chosen locations (i.e., first and second, second and third, etc.). All datapoints
within each corridor are plotted in the diagram unless they're excluded by
the program because they're too close to another datapoint. A map is drawn
in the upper-right corner showing the cross section location, datapoints and
path.
UACROSS KMIA KBUF MAP=YES IDLABEL=NAMES PARAM=MIX THA SPD
This entry
displays a cross section of mixing ratio, potential temperature and wind speed
using the attributes defined for each parameter in the UACROSS.USER, .SITE or .CORE file.
The cross section runs from Miami to Buffalo and includes datapoints within
a 500 km-wide corridor between the two cities. The plotted stations are labeled
with their 4-character IDs instead of their 5-digit ID numbers (e.g., KJAX
instead of 72206). A map is drawn in the upper-right corner showing the cross
section location, datapoints and path.
UACROSS KSLE KBOI 72672 KLBF PARAM=TD[F] SPDN[MPH] COLOR=2 3
This entry
displays a cross section of dewpoint temperature and wind speed normal to the
cross section. The units and graphics color levels specified in the command
(F and 2 for TD; MPH and 3 for SPDN) override the settings in the UACROSS.* files.
Because there are more than two locations specified and the default for the
CORRIDOR keyword in this case is NO, only the four specified stations (Salem,
Boise, Riverton, and North Platte) are included in the cross section.
UACROSS '38:40 09:10' 08221 07645 12843 UKKK MAP=YES CORRIDOR=YES
LABEL='UACROSS across Europe' X 5 5 12
This entry
displays a cross section of potential temperature for the five specified locations
and the datapoints within the 500 km-wide corridors between each of pair of
locations. As shown in this example, locations can be specified as latitude/longitude
pairings enclosed in single quotes, 5-digit ID numbers or 4-character IDs.
A map is drawn in the upper-right corner showing the cross section location,
datapoints and path. The text UACROSS across Europe is plotted in
graphics color level 3 and pixel size 12 near the top-left corner of the frame.
UACROSS KMIA KIAD MAP=YES DAY=#Y TIME=0 FHOUR=12 DATASET=RTGRIDS/ETA
INCREMENT=2 2 CORRIDOR=YES 100[KM]
This entry
displays a cross section of potential temperature between Miami and Washington,
D.C. using the 12-hour forecast grids from today's 0 UTC run in the dataset
RTGRIDS/ETA. The INCREMENT and CORRIDOR keywords work together to keep the
number of grid points selected as datapoints to a reasonable limit of 15 or
less. In this example, those keywords ensure that only grid points from every
other row and column that are within 100 km of the axis from Miami to Washington
D.C. are selected as datapoints. A map is drawn in the upper-right corner showing
the cross section location, datapoints and path.
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