ExampleSonde {RadioSonde} | R Documentation |
This data was collected by a radiosonde which was carried aloft by a
weather balloon. This data was collected as part of a special field
program, but the instrument and data formats are very common
in the atmospheric community.
Fundamentally; temperature, pressure, and humidity sensors are bundled
with a radio transmitter and are either sent aloft on a balloon
(rawindsonde) or tied to a small parachute and dropped from a plane
(dropsonde). Either way, the location of the sonde is observed
(either visually or with GPS), the data from the radio transmitter
recorded, and the result is an ascii file that contains a header
(of varying length) with descriptive information followed by a
table of information.
For rawindsondes, the first entry for the table is actually the
surface data from the weather station, but the remaining entries
are from the sonde. Also, the wind is inferred from the position
of the balloon. Since this is real data, there are missing
values – which arise all the time. If you get a profile
without missing values, you can be sure it is synthetic or interpolated.
The datastreme ends when the operator calls it quits. This happens when
a) the balloon breaks, or b) the radio reception has so many dropouts that
is is not worth it anymore. Different fields have different missing
flags. Where possible, we replace the "standard" missing flags with
NaN
ExampleSonde
is the nominal output and is a mixture of ancillary
data (contained in the first ???? lines of the file), and the instrument
measures and some derived fields that follow in a fixed-format table
with an unknown number of lines.
Field | varname | width | format | description | units | missing value |
[ 1] | time | 6 | F6.1 | Time | Seconds | 9999.0 |
[ 2] | press | 6 | F6.1 | Pressure | Millibars | 9999.0 |
[ 3] | temp | 5 | F5.1 | Dry-bulb Temperature | Degrees C | 999.0 |
[ 4] | dewpt | 5 | F5.1 | Dew Point Temperature | Degrees C | 999.0 |
[ 5] | rhum | 5 | F5.1 | Relative Humidity | Percent | 999.0 |
[ 6] | uwind | 6 | F6.1 | U Wind Component | Meters/Second | 9999.0 |
[ 7] | vwind | 6 | F6.1 | V Wind Component | Meters/Second | 9999.0 |
[ 8] | wspd | 5 | F5.1 | Wind Speed | Meters/Second | 999.0 |
[ 9] | wdir | 5 | F5.1 | Wind Direction | Degrees | 999.0 |
[10] | dz | 5 | F5.1 | Ascension Rate | Meters/Second | 999.0 |
[11] | lon | 8 | F8.3 | Longitude | Degrees | 9999.0 |
[12] | lat | 7 | F7.3 | Latitude | Degrees | 999.0 |
[13] | range | 5 | F5.1 | Variable (see below) | 999.0 | |
[14] | angle | 5 | F5.1 | Variable (see below) | 999.0 | |
[15] | alt | 7 | F7.1 | Altitude | Meters | 99999.0 |
[16] | qp | 4 | F4.1 | QC flag for Pressure | Code (see below) | 99.0 |
[17] | qt | 4 | F4.1 | QC flag for Temperature | Code (see below) | 99.0 |
[18] | qh | 4 | F4.1 | QC flag for Humidity | Code (see below) | 99.0 |
[19] | qu | 4 | F4.1 | QC flag for U Component | Code (see below) | 99.0 |
[20] | qv | 4 | F4.1 | QC flag for V Component | Code (see below) | 99.0 |
[21] | quv | 4 | F4.1 | QC flag for Ascension Rate | Code (see below) | 99.0 |
The missing value
flags are in brackets [].
Fields 13 and 14 are `variable' because depending on the sounding
system the variables used in these positions can vary.
Fields 16 through 21 contain the Quality Control information (flags)
generated at JOSS. These flags are based on the automated or
visual checks made.
The JOSS QC flag codes are as follows:
http://www.joss.ucar.edu/cgi-bin/codiac/dss?2.151
getsonde
,
plotsonde
,
skewt.lines
,
skewt.points
filename <- system.file("exampleData", "ExampleSonde.txt", package = "RadioSonde") sample.sonde <- getsonde(filename)