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Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Advances in polarimetric X-band weather radarTobias Otto
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Contents• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Compact, easily deployable and cheaper than the usual S- or C-band weather radars.
Used for dedicated, short-range (< 60km) applications such as• gap-filling radars in complex terrain such as moutainous areas, e.g.
- RHyTMEE project of Météo France
• high-resolution precipitation measurement in densly populated areas in order toimprove urban water management and flood prediction, e.g. - polarimetric X-band radar network in Tokyo, Japan (http://www.bosai.go.jp/kiban/radar) - RAINGAIN project in Paris, Rotterdam, London and Leuven (http://www.raingain.eu) - CASA Dallas Fort Worth Urban Demonstration Network (http://www.casa.umass.edu/)
• improve the low-altitude radar coverage
They can provide a higher temporal and spatial resolution than standard operational weather radars due to the reduced range coverage and less stringent requirements on the scanning strategy due to their focused application.
But• attenuation due to rain is stronger than at S- or C-band, total signal extinction within
few kilometres is possible in a cloudburst (instantaneous rain rates >100 mmh -1)
• resonance scattering (Mie scattering) occurs in moderate to strong rain
Why X-band*?
*electromagnetic frequency band from 8 – 12 GHz
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
radar.dhigroup.com
metek.de
Marine radars turned into weather radars.
usually power measurement onlywith fan beam antenna coarse resolution in elevationgood for a spatial overview of precipitation but
not for quantitative precipitation estimation (QPE) cheap
gematronik.com
novimet.com
Dedicated polarimetric weather radars.
beside power also Doppler and polarimetricmeasurements
very good for quantitative precipitation estimationnot that cheap
The two X-band weather radar worlds
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Most hydrometeors are not spherical, andthey show distinct polarimetric signatures at microwave frequencies.
- ice particles
- hail
- raindrops
Beard, K.V. and C. Chuang: A New Model for the Equilibrium Shape of Raindrops, Journal of the Atmospheric Sciences, vol. 44, pp. 1509 – 1524, June 1987. http://commons.wikimedia.org/wiki/Category:Hail
Why polarimetry?
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
linear horizontal / vertical polarisations (H and V)
Motivation:- easier to understand especially for the weather radar user community
- close to the characteristic / principal polarisations for measurementsat low elevations, i.e. low depolarisation
- differential measurements (power, phase) between H and V are directlylinked to the anisotropy (oblateness) of the hydrometeors
What to measure?- ideally the complex polarisation scattering matrix which links the incident electric
field vector Ei with the backscattered electric field vector Es
re
EE
SSSS
EE jkr
iv
ih
vvvh
hvhhsv
sh
Which polarisations are used?
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Zhh (dBZ)
Zvh (dBZ)
Zhv (dBZ)
Zvv (dBZ)
transmit
rece
ive
(alternate polarisation mode)
Measurement principle
Data: C- Band POLDIRAD (DLR, Oberpfaffenhofen, Germany), Prof. Madhu Chandra
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Zhh (dBZ)
Zvh (dBZ)
Zhv (dBZ)
Zvv (dBZ)
transmit
rece
ive
-= Zdrdifferentialreflectivity
Data: C- Band POLDIRAD (DLR, Oberpfaffenhofen, Germany), Prof. Madhu Chandra
Differential reflectivity
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
dBZlog10 2hhhh PCRZ dBlog10
vv
hhdr P
PZ
Differential ReflectivityReflectivity
rainmelting layeraggregates (snow)ice crystals
Data: C- Band POLDIRAD (DLR, Oberpfaffenhofen, Germany), Prof. Madhu Chandra
Differential reflectivity
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Zhh (dBZ)
Zvh (dBZ)
Zhv (dBZ)
Zvv (dBZ)
transmit
rece
ive -
= LDR (dB)linear depolar-
isation ratio
Data: C- Band POLDIRAD (DLR, Oberpfaffenhofen, Germany), Prof. Madhu Chandra
Linear depolarisation ratio
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
dBZlog10 2hhhh PCRZ dBlog10
vv
hv
PPLDR
Linear Depolarisation RatioReflectivity
melting layerground clutter
Data: C- Band POLDIRAD (DLR, Oberpfaffenhofen, Germany), Prof. Madhu Chandra
Linear depolarisation ratio
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
range-normalised microwave propagation through rain
range r
phase difference between H and Vdifferential phase Φdp (deg)
range
The slope of the differential phase is calledspecific differential phase:
12
121
2)()(
kmdegrr
rrK dpdp
dp
The measurement of the differential phase is crucial for polarimetric X-band weather radars because it is:
- independent from radar calibration - independent from partial beam blocking and attenuation as long as the signal is not totally extinct - almost linearly related to rain attenuation - very useful at X-band for rainfall rate estimation when R 3 mm h-1
Differential phase
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
attenuation A
differential propagation phase Φdp
propagation(forward-scattering)
backward-scattering
differential backscatter phase δco
reflectivity Z
Power and differential phase measurements by X-band weather radars are always a combination of propagation and backward-scattering effects that need to be separated before analysing the weather radar data.
drrrZrZnr
rrnn
1
1
2' α
1
1
2 ( )nr
dp n co n dpr r
r r K r dr
X-band challenge
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
0.5°
reflectivity (dBZ)
differential phase (deg)
differential reflectivity (dB)
Data: TU Delft X-band IDRA, data freely available at http://data.3tu.nl/repository/collection:cabauw
differential backscatter phase(an indicator of resonance/Mie scattering)
differential attenuation
A clutter-filtered polarimetric X-band weather radar measurement.
X-band challenge
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contens
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• attenuation can be estimated via the specific differential phase Kdp:
X-band scattering computation using measured drop-size distributions(by 2D-video disdrometer) and several raindrop-shape models
• rule of thumb for S-, C- and X-band:whenever microwave attenuation due to rain is substantial, the differential phase accumulation is significant enough that Kdp can be estimated
αhh specific one-way attenuation at horizontal polarisation (dB km-1)
αh-v differential attenuation (dB km-1), i.e. αh-v=αhh- αvv
Estimation of attenuation
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• a more complex attenuation correction method relies on the determination of the path-integrated attenuation (PIA), e.g. by
• differential phase (no estimation of Kdp required),• power measurement of a fixed target at far range (ground clutter), …
• the PIA is distributed over the range bins weighted by the reflectivity
bzaα
0.1
0.11
' 10 1
: 10 1 :
b b PIAn
n b PIAN n N
z rr
I r r I r r
: 0.46 'N
n
rb
n N nr r
I r r b z r dr
α specific one-way attenuation (dB km-1)
z reflectivity in linear units (mm6m-3)z′ attenuated reflectivity (mm6m-3)
PIA (dB)
Estimation of attenuation
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
2011-09-10 19:45:19UTC, az. 324.4 deg
Goal is the estimation of the slope of the differential propagation phase Kdp.
1
1
2 ( )nr
dp n co n dpr r
r r K r dr
most likely differentialbackscatter phase
Data: TU Delft X-band IDRA, data freely available at http://data.3tu.nl/repository/collection:cabauw
Differential phase processing
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
2011-09-10 19:45:19UTC, az. 324.4 deg
Goal is the estimation of the slope of the differential propagation phase Kdp.
Most common method:Linear regression with a runningwindow length of about 1-3km.
Disadvantage:• leads to negative Kdp in the presence
of differential backscatter phase• reduced range resolution of the
resulting Kdp
• Kdp peaks are underestimated
Differential phase processing
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
2011-09-10 19:45:19UTC, az. 324.4 deg
Goal is the estimation of the slope of the differential propagation phase Kdp.
• the difference of Ψdp between the ranges ra and rb can be distributed among the range bins including a weighting with the reflectivity zhh and the differential reflectivity zdr
with
• the differential reflectivity is closely related to the backscatter phase,
0.69 0.42
0.69 0.42
range
12dp n dp
hh n dr n
hh dr
K r wr
z r z rw
z z
(coefficients valid for rain, X-band, zhh and zdr in linear units)
brar
ΔΨdp = Ψdp(rb) – Ψdp(ra)
X-band scattering computations based onraindrop-size distributions measured by a disdrometer
Differential phase processingAATTMMOOSS
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
2011-09-10 19:45:19UTC, az. 324.4 deg
Goal is the estimation of the slope of the differential propagation phase Kdp.
• the difference of Ψdp between the ranges ra and rb can be distributed among the range bins including a weighting with the reflectivity zhh and the differential reflectivity zdr
with
• the differential reflectivity is closely related to the backscatter phase,ra and rb can be chosen such thatZdr(rb) - Zdr(ra) 0, therefore δco(rb) - δco(ra) 0,
in this case, ΔΨdp is due to the differential propagation phase only.
0.69 0.42
0.69 0.42
range
12dp n dp
hh n dr n
hh dr
K r wr
z r z rw
z z
(coefficients valid for rain, X-band, zhh and zdr in linear units)
brar
ΔΨdp = Ψdp(rb) – Ψdp(ra)
Differential phase processing
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
attenuated reflectivity (dBZ)
differential phase (deg)
attenuated differential reflectivity (dB)corrected reflectivity (dBZ) corrected differential reflectivity (dB)
specific differential phase (deg km-1) differential backscatter phase (deg)
The separation of the forward- and backward-scattering components is crucial at X-band.
Only after a separation of both components, the data can be further processed and analysed (rainfall rate retrieval, hydrometeor classification).
A clutter-filtered polarimetric X-band weather radar measurement.
X-band challenge
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
The weather radar measurements are connected via the raindrop-size distribution (RDSD)to meteorological parameters such as liquid water content or rainfall rate.
• Raindrop-size distribution normalised with respect to the liquid water content:
Nw .. concentration parameterD0 .. median volume diameterµ .. shape parameter
• for simplicity, often µ = 0 is assumed such that the RDSD becomes a two-parameter exponential distribution
0-(3.67 )
0
( ) ( ) eD
µD
wDN D N f µD
4
4
6 (3.67 )( )3.67 ( 4)
µµf µµ
Raindrop-size distribution
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
4
18 6 1825
10 ( ) 10 ( )D D
z D N D dD D N D dDK
• reflectivity (mm6m-3)
9 3LWC 10 ( )6 D
D N D dD • liquid water content (mm3m-3)
6 33.6 10 ( ) ( )6 D
R D v D N D dD • rainfall rate (mm h-1)
terminal fall velocity (m s-1)
raindrop volume
• specific differential phase (deg km-1) 318010 ( ) ( ) ( )dp hh vvD
K f D f D N D dD
valid for Rayleigh scattering
wavelength
dielectric factorradar coss-section
forward-scattering amplitudes
Meteorological parameters:
Polarimetric weather radar measurements:
Raindrop-size distribution
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
X-band scattering computations based onraindrop-size distribution measured by a disdrometer
reflectivity zhh
specific differentialphase Kdp
Variability due to:• raindrop-size distribution
numeric example assuming Rayleigh scattering
A fixed parameterisation of Z-R / Kdp-R relations leads to uncertainties due to the natural variability of rainfall.
• raindrop shape (Kdp)
Note:• Kdp can be estimated up to ~0.1 deg,
only useful for instantaneous rainfall rates larger than ~3 mmh-1 at X-band
• Kdp – based rainfall rate estimates tend to be more accurate also due to its independence from radar calibration and signal attenuation
raindropdiameter #/m3 Z water volume
per cubic meter1 mm 4096 36 dBZ 2144.6 mm3
4 mm 1 36 dBZ 33.5 mm3
Logarithmic scale.Z-R / Kdp-R relations are not linear!
Rainfall rate estimation
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Data processing and rainfall rate estimation of the TU Delft polarimetric X-band radar IDRA:
• spectral clutter suppression [1]
• estimation of the specific differential phase Kdp [2](reflectivity-weighted to overcome the coarse range-resolution of conventional Kdp estimators, the estimated Kdp is unaffacted by signal attenuation and independent of the radar calibration)
• estimation of the one-way specific attenuation by αhh = 0.34∙Kdp with αhh (dB km-1) and Kdp (deg km-1) and attenuation correction of the reflectivity
• the parametrisations for the rainfall rate estimation are based on 41530 raindrop-size distributions measured by a 2D-video disdrometer data at Cabauw (Netherlands) in 2009:
• zhh = 243∙R1.24 with the rainfall rate R (mm h-1) and the reflectivity at horizontal polarisation zhh (mm6 m-3)
• R = 13∙Kdp0.75 with the rainfall rate R (mm h-1) and the one-way specific differential phase Kdp (deg km-1)
• for the final rainfall rate product, R(Kdp) is chosen if the reflectivity is above 30 dBZ, and the standard deviation of Kdp is below 2 deg km-1, else R(zhh) is used
[1] C. Unal, 2009: Spectral Polarimetric Radar Clutter Suppression to Enhance Atmospheric Echoes,J. Atmos. Oceanic Technol., 26, 1781–1797.
[2] T. Otto and H.W.J. Russchenberg, 2011: Estimation of Specific Differential Phase andDifferential Backscatter Phase from Polarimetric Weather Radar Measurements of Rain,IEEE Geosci. Remote Sens. Lett., 8, 988-992.
Rainfall rate estimation
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
corrected differential reflectivity (dB)corrected reflectivity (dBZ)
specific differential phase (deg km-1) differential backscatter phase (deg)
A clutter-filtered polarimetric X-band weather radar measurement.
rainfall rate estimate (mm h-1)
Rainfall rate estimation
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Hydrometeor classification• the hydrometeors (snow, ice, rain, hail) show different polarimetric signatures a classification is possible and can improve rainfall rate estimation
Adaptive clutter suppression• robust suppression of clutter (ground targets, birds, planes) is possible taking
advantage of the different polarimetric signatures see next presentation by Christine Unal
Raindrop-size distribution retrieval• the polarimetric parameters can be combined to estimate the parameters of
the raindrop-size distribution and to improve the rainfall rate estimation
Further applications of radar polarimetry
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• major limitation of X-band weather radar systems is attenuation in heavy rain / wet hail:
• if the purpose of an X-band radar is the observation of heavy precipitation:• instead of using a single X-band radar, use a network of X-band radars, or• complement the X-band radar measurements with measurements of the
operational weather radar network (S- or C-band observations).
ΔΨ = 180 deg, that correspondsto ~60 dB round-trip attenuationover 8 km distance!
Data: TU Delft X-band IDRA, data freely available at http://data.3tu.nl/repository/collection:cabauw
Limitations of X-band radar
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• most commercially available polarimetric weather radars do not employ the alternate polarisation mode, instead they use the “simultaneous H/V mode”: simultaneous transmission of a horizontally and a vertically polarised wave with equal amplitude they will combine dependening on their phase offset to an elliptically polarised wave the radar measures a combination of co- and cross-polarised scattering matrix components:
only in case of very low cross-polarisation!
Advantages• no need of a high-power ferrite switch• double unambiguous Doppler velocity interval
Disadvantages• very demanding requirements on the radar cross-polarisation isolation• depolarisation in the melting layer / ice clouds will deteriorate the measurements• reduced accuracy of polarimetric weather radar measurements due to cross-pol component• no measurement of the linear depolarisation ratio, instead cross-correlation coefficent • loss of 3dB in sensitivity compared to alternate mode because the transmit power is split
equally over the H and V transmit channel
s i i ih hh h hv v hh h
s i i iv vh h vv v vv v
E S E S E S E
E S E S E S E
Simultaneous H/V mode
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• important antenna specifications for polarimetric weather radars are• high resolution in azimuth and elevation, i.e. pencil beam (large directional gain),• ideally equal specifications for horizontal and vertical polarisation
(e.g. matched co-polarised beam patterns, S-parameters),• low cross-polarisation levels.
• usually parabolic reflector antennas are employed by polarimetric weather radars
• there is some on-going research in order to use phased-array antennas,e.g. by the Engineering Research Center for Collaborative Adaptive of the Atmosphere (CASA, USA)[1]:
• 64 T/R modules with 1.25W transmit power each• electronic phase steering in azimuth (±45 deg) and mechanical steering in elevation• elevation beamwidth of 2.8 deg, azimuth beamwidth of 1.8 deg – 2.4 deg• alternate polarisation mode due to limited cross-polarisation isolation
[1] J.L. Salazar, E.J. Knapp and D.J. McLaughlin, 2010: Dual-polarization performance of the phase-tilt antenna array in a CASA dense network radar, Geoscience and Remote Sensing Symposium, IGARSS 2010, 3470-3473.
Phased-array antennas
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• first commercial systems are on the market that use solid-state transmitter instead of the traditionally used high-power microwave sources:
• long lifetime• compact, no high-power microwave circuits (waveguides etc.)• combined with an arbitrary waveform generator (e.g. direct digital-synthesizer), high
flexibility of the transmitted waveform software-defined radar• to retain the sensitivity of such systems, pulse-compression is employed
• e.g. alternate transmission of a modulated long pulse (~50 µs) for far-range measurements and a short pulse (~1 µs) for close-range measurements
time
Txlong Rxlong Txshort Rxshort Txlong Rxlong
far-range measurement close-rangemeasurement
combination
Solid-state transmitter
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
IDRA is mounted on top of the 213 m high meteorological tower.
CESA
R – C
abau
w Ex
perim
enta
l Site
for A
tmos
pher
ic Re
sear
chSpecifications• 9.475 GHz central frequency• FMCW with sawtooth modulation• transmitting alternately horizontal and vertical
polarisation, receiving simultaneously the co- and the cross-polarised component
• 20 W transmission power• 102.4 µs – 3276.8 µs sweep time• 2.5 MHz – 50 MHz Tx bandwidth• 60 m – 3 m range resolution• 1.8° antenna half-power beamwidth
ReferenceJ. Figueras i Ventura: “Design of a High Resolution X-band Doppler Polarimetric Weather Radar”, PhD Thesis, TU Delft, 2009. (online available at http://repository.tudelft.nl)
Near real-time display:http://ftp.tudelft.nl/TUDelft/irctr-rse/idra
Processed and raw data available at:http://data.3tu.nl/repository/collection:cabauw
TU Delft X-band weather radar: IDRA
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
• motivation
• weather radar polarimetry
• X-band challenge
• radar data processing• attenuation correction• differential phase processing
• raindrop-size distribution
• quantitative precipitation estimation (QPE)
• further applications
• limitations of X-band weather radar
• radar technologies for polarimetric X-band weather radar
Contents
Remote Sensing of the Environment
AATTMMOOSS
AATTMMOOSS
DelftUniversity ofTechnology
Advances in polarimetric X-band weather radar
Tobias Otto
e-mail [email protected]
web http://atmos.weblog.tudelft.nl
radar data http://data.3tu.nl/repository/collection:cabauw
references R. E. Rinehart, “Radar for Meteorologists”,Rinehart Publications, 5th edition, 2010.
V. N. Bringi and V. Chandrasekar, “Polarimetric Doppler Weather Radar: Principles and Applications”, Cambridge University Press, 1st edition, 2001.
R. J. Doviak and D. S. Zrnić, “Doppler Radar and Weather Observations”, Academic Press, 2nd edition, 1993.