Transcript Presentation

High resolution atmospheric profiling with the
S-band Doppler polarimetric radar TARA
Christine Unal, Marta Girame Ibanez, Yann Dufournet and Herman Russchenberg
Delft University of Technology, The Netherlands
 TARA type of measurement
 Near vertical wind profiling mode
 First comparisons of TARA wind profiling with radiosondes
International Research Centre for Telecommunications and Radar
Hornisgrinde (site H)
TARA (Transportable
Atmospheric Radar)
wavelength = 9.1 cm
1 s < time resolution < 10 s
3 m< height resolution< 30 m
can simultaneously measure
4.5 Tb of raw data
 dynamics (wind profiling with 3 beams)
 microphysics (polarimetry)
of precipitation, ice clouds, mixed-phased clouds and clear air scattering
International Research Centre for Telecommunications and Radar
Measurement configuration
MB
VV HV HH OB1 OB2
time
measurement sequence
3 beams  3 mean Doppler velocities
 horizontal wind + vertical wind
International Research Centre for Telecommunications and Radar
1.3 m/s
2.5 m/s
Radiosondes
comparison
Sites H and M
About 30 mn
time difference
6.5 deg.
17.6 deg.
International Research Centre for Telecommunications and Radar
IOP-5a: reflectivity and horizontal wind
International Research Centre for Telecommunications and Radar
Comparison of TARA horizontal wind with radiosonde H
Standard deviation (radar measurement of 3 mn)
Wind speed: from 1 m/s (cloud) to 2 m/s (rain)
Wind direction: from 2 deg. (cloud) to 5 deg. (rain)
Differences of the order of 5 m/s
and 25 deg. between TARA and
radiosonde H
International Research Centre for Telecommunications and Radar
IOP-5a: horizontal wind and vertical
velocity (zoom on 6 mn)
heterogeneity
International Research Centre for Telecommunications and Radar
IOP-8b:
reflectivity
and 3D wind
International Research Centre for Telecommunications and Radar
Comparison of TARA horizontal wind with radiosondes
Compared to precipitation, clear air
scattering has a low signal-to-noise ratio
and less data for the averaging period
Differences of the order of 5 m/s
and 90 deg. between TARA and
radiosonde H
International Research Centre for Telecommunications and Radar
IOP-8b: 3D wind (zoom on 30 mn)
turbulence
International Research Centre for Telecommunications and Radar
Status
 atmosphere dynamics  evaluation of TARA wind estimates
- different meteorological conditions
- accuracy
- COPS user needs
 atmosphere microphysics  research on mixed-phased clouds
(Yann Dufournet)
 problems with TARA during COPS  data quality ok (raw data) but a part
of the processing is thus not automatic  study cases will be selected
International Research Centre for Telecommunications and Radar
IOP-5a: 3 time
series of mean
Doppler velocities
International Research Centre for Telecommunications and Radar
IOP-8b: 3 time
series of mean
Doppler velocities
International Research Centre for Telecommunications and Radar