Snowfall Rate Retrieval with Satellite Passive Microwave Measurements and Algorithm Validation
GV for Snowfall Retrieval Research
description
Transcript of GV for Snowfall Retrieval Research
GV for Snowfall GV for Snowfall Retrieval ResearchRetrieval Research
David HudakDavid Hudak
Paul JoePaul Joe Environment EnvironnementCanada Canada
2nd International GPM Ground Validation Workshop, 27-29 September, Taipei, Taiwan
Ref: WMO Publication No. 9 Volume ARef: WMO Publication No. 9 Volume A
All active Synoptic Stations north of 50 N
90° N
75° N
60° N
45° N
247729 Oct 200129 Oct 2001
POSS OccurrencePOSS Occurrence(1 minute data)(1 minute data)
•Surface obs•Doppler XBand•Derived Snowrates•Minutely•Snow only•Typed by observer•1 winter of data
YEV=Inuvik 68°NYUL=Montreal 45°N
Vertical Profile AnalysisVertical Profile AnalysisFort Simpson (62Fort Simpson (62°°N)N) Montreal (45°N)(45°N)
Quantifying Snow Gauge Errors
Systematic errors:
WIND (temperature) wetting loss evaporation loss non-zero trace
capping of gauge orifice
blowing snow
Goodison et al
0
20
40
60
80
100
120
0 1 2 3 4 5 6 7 8 9
Wind speed at gauge height (m/s)
Rat
io o
f gau
ge c
atch
to th
e D
FIR
(%)
Canadian Nipher NWS 8" AlterNWS 8" unsh Hellmann unshTretyakov
WMO Intercomparison Study Results
Catch Efficiency vs Wind for the 4 most widely used gauges
Precipitation Occurrence Sensing System (POSS)
•Doppler •Mie Scattering•Terminal Velocity
•XBand •Bistatic•Continuous Wave
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2POSS Estimate/DFIR
0
0.1
0.2
0.3
0.4
0.5
Re
lati
ve
fre
qu
en
cy
Egbert,O nt. Sept 1997-Feb 200459 observations (tw ice daily)so lid precip ita tion onlyT<0C ; D FIR >=1 m m
R PR PV
POSS Research Applications Quantitative Precipitation Estimation (QPE)
• Solid precipitation rate validation using the Double Fence Intercomparison Reference (DFIR)
Under over
POSS Research ApplicationsQPE Snow Density
0.0 0.10.02 0.04 0.06 0.08 0.20
Average density (gcm -3)
1
2
0.90.8
0.7
0.6
0.5
0.4
0.3
0.2
PO
SS
(RP
)/D
FIR
E gbert, O nt. Sept1997 to Feb 200454 observations (tw ice daily)R P m ethod assum ing snow density=0.1 gcm -3
Tem p. <0 C ; W ind<20kts; D FIR >0.1m m
0.01 0.10.02 0.04 0.060.08 0.2
A verage density (gcm -3)
0.6
0.8
1
1.2
1.4
Ave
rag
e m
ode
velo
city
(m
s-1
)
Egbert, O nt. Sept1997 to Feb 200446 observations (tw ice daily)Tem p. <0 C ; W ind<10kts; D FIR >0.1m m
1 minute snow water equivalent precipitation rate
Hot plate insensitive
18:00 19:00 20:00 21:00 22:00 23:00 0:00Time
0
1
2
3
4
Sn
ow
f al l
wa
ter
eq
uiv
ale
ntp
r ec i
pi ta
ti on
r ate
( mm
h-1)
AIRS2 Mirabel SnowEnding: 031218 00:00Observer total amount= 4.8 mm
Hot Plate1(5.23 mm)Hot Plate2 (4.69 mm)POSS (5.18 mm)
POSS Research ApplicationsAirport Vicinity Icing and Snow Advisor (AVISA)
NCAR/DRI Hot Plate
Centre fo Atmospheric Research ExperimentsCentre fo Atmospheric Research ExperimentsEC field project deployment suite
Penn StateSpectrometer
Wind Profiler
HotPlates
X-bandRadar
Univ. of AlaskaW-bandRadar
McGill Univ.
Video Disdrometer
10m met towerRadiation sensorsVisibility meterCeilometer
MW Radiometer
POSS
W-band:
•Nadir and Vertical-up: Z, LDR, Vd
•Vertical-up – side: Polarimetric, Vd
•Nadir-Side: Polarimetric, Doppler
•Nadir – Nadir-aft – Dual-Doppler
•Side – Side-forward – Dual-Doppler
X-band:
•Nadir and vertical-up – Single polarization
•Side - Polarimetric
NRC Airborne W/X – band radar (NAWX)
Fully Polarimetric and Doppler W-band: Five ports – Electronic switching X-band: Two ports - Electronic switching
CONVAIR-580 CLOUD MICROPHYSICS (cntd)
C a n a d a
Standard PMS 2D Imagery
800 um
6400 um
Under-wing particle probes
POSS Research ApplicationsPrecipitation Typing
Doppler Spectral Mode Analysis
RAIN SNOW
Mixed SNOW & RAIN
YHMYKF
King City C-band Dual Polarized radar
ZR-IP-S
Correlation Coefficient ρhv
C-band Polarization parameters
Correlation Coefficient ρhv
Differential Reflectivity ZDR
Reflectivity Z
Specific Differential Phase kdp