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Olivier P. PratOlivier P. Prat 11, Brian R. Nelson, Brian R. Nelson 22, and Scott E. Stevens, and Scott E. Stevens 11

11Cooperative Institute for Climate and Satellites and NOAA/NCDC, Asheville, NC Cooperative Institute for Climate and Satellites and NOAA/NCDC, Asheville, NC 22Remote Sensing Applications Division, NOAA/NESDIS/NCDC, Asheville, NCRemote Sensing Applications Division, NOAA/NESDIS/NCDC, Asheville, NC

ERAD 2012 ERAD 2012 77thth European Conference on Radar in Meteorology and HydrologyEuropean Conference on Radar in Meteorology and Hydrology

June 25June 25--28, 201228, 2012

CHARACTERIZATION OF PRECIPITATION

FEATURES IN THE SOUTHEASTERN UNITED

STATES USING HIGH SPATIAL AND TEMPORAL

RESOLUTION QPE DERIVED FROM THE NATIONAL

MOSAIC AND MULTI-SENSOR QPE (NMQ/Q2)

• NMQ Reanalysis: 1998-2010 for a pilot domain (9 NEXRAD)

• Precipitation: Seasonal, daily, hourly, by event

• NMQ Comparison with:

• TRMM Satellite products (2A25, 3B42)

• Rain gauge data (70 RG in dense Network)

• Conclusion and Future work

ERAD 2012 25-29 June, Toulouse

Outline

• Developed at the National Severe Storms Laboratory (NSSL)

• Estimates of Precipitation

• Primary surface Radar based

• Incorporates RUC model data and gauge networks

• Represents significant step in resolution

• 1-km spatial resolution

• 5-min temporal resolution

ERAD 2012 25-29 June, Toulouse

National Mosaic and Multi-sensor QPE (NMQ/Q2)

ERAD 2012 25-29 June, Toulouse

NMQ

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• 9 Radar Sites over the Carolinas

• 13-yr of Level II data

ERAD 2012 25-29 June, Toulouse

NMQ Reanalysis Pilot Project (1998-2010)

• Collaboration CICS-

NC, NCDC, NSSL,

RENCI, NC State Univ.

• Data Management and

organization

• TBs of data

• CPUs

70 RGs

NMQ/Q2 : Seasonal Precipitation (1km)

Win

ter

Sum

mer

Spring

Fall

Blockage

Terrain

Blockage

Terrain

Blockage

Buildings

Blockage

Buildings

Gulf

Stream

Gulf

Stream

Side

Lobe

Side

Lobe

Sea

Breeze

Sea

Breeze

NMQ/Q2 : Maximum Daily Precipitation

Win

ter

Sum

mer

Spring

Fall

Winter

Storm/Snow

Winter

Storm/Snow

Tropical

Cyclones

Tropical

Cyclones

Floyd

(1999)

Floyd

(1999)

Isabel

(2003)

Isabel

(2003)

NMQ/Q2 : Maximum Hourly Precipitation

Win

ter

Sum

mer

Spring

Fall

Seasonal Distribution of

Storms

Seasonal Distribution of

Storms

Storm TracksStorm Tracks

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ERAD 2012 25-29 June, Toulouse

Precipitation Features : Warm Season Event

Hurricane Frances (2004/09/07 : 1235UTC)

1235UTC

1200UTC

3-hr

1235UTC

� Comparable patterns for rainfall distribution

� Local differences (beam blocking, rain-rate estimation algorithms, sensors, sites processed …)

5-min25

-km

1-km

5-km1-km

ERAD 2012 25-29 June, Toulouse

Precipitation Features : Cold Season Event

1200UTC

� Higher instant precipitation for NMQ than for TPR 2A25

� Higher 3-day Accumulation for NMQ with more detailed pattern at the ground

25-k

m1-

km

5-km1-km

0230UTC

�

�

�

�

�

�

�

�

�

�

�

�

2004 Christmas Eve Snowstorm (2004/12/26 : 0230UTC)

3-day 5-min

ERAD 2012 25-29 June, Toulouse

Seasonal differences TPR 2A25 and NMQ (5km)

2A25

Sum

mer

NM

Q S

umm

er

Diff. S

umm

er

� Important differences over the mountains (beam blocking)

� WINTER & SPRING : TPR 2A25 > NMQ

� SUMMER & FALL : NMQ > TPR 2A25

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

DJF MAM JJA SON YEAR

ΣΣ ΣΣ [2

A25

- Q

2]/2

A25

(-)

ERAD 2012 25-29 June, Toulouse

Seasonal differences TMPA 3B42 and NMQ (25km)

Win

ter

Sum

mer

Spring

Fall

� Important differences over the mountains (beam blocking)

� Important differences along the coasts (sea breeze)

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ERAD 2012 25-29 June, Toulouse

Seasonal PDFs (1998-2010)

0.00

0.05

0.10

0.15

0.1 1 10 100

Rel

ativ

e R

ain

Vol

ume

(%)

Rain Rate (mm/h)

TRMM TMPA 3B42

DJF

MAM

JJA

SON

0.00

0.05

0.10

0.15

0.1 1 10 100

Rel

ativ

e R

ain

Vol

ume

(%)

Rain Rate (mm/h)

NMQ/Q2

DJF

MAM

JJA

SON

� Higher seasonal variability for NMQ/Q2 PDFs

� Summer NMQ/Q2 PDF indicates higher rain rates (convective events)

� Winter NMQ/Q2 PDF indicates a more widespread rain rate contribution

(cold precipitation: snow, mixed phase …)

TRMM 3B42 NMQ

� Lower Avg. Rain Rate (-11%) for NMQ during the cold season (DJF-SON)� Higher Avg. Rain Rate (+17%) for NMQ during the warm season (MAM-

JJA)� Higher Annual Rain Rate for NMQ (+8%)

0

1

2

3

4

DJF MAM JJA SON YEAR

Aver

age

Rai

n R

ate

(mm

/h)

NMQ/Q2 TRMM 3B42

ERAD 2012 25-29 June, Toulouse

Low/High Rain Rate ContributionTRMM 3B42 NMQ

� Higher contribution for Q2 in the low rain intensity domain(RR<1mm/h)

���� Higher sensitivity for low rain-rate detection

0%

20%

40%

60%

80%

100%

DJF MAM JJA SON YEAR

Rai

n R

ate

Con

trib

utio

n (%

)

TRMM 3B42 RR>10mm/h 1<RR<10mm/h RR<1mm/h

0%

20%

40%

60%

80%

100%

DJF MAM JJA SON YEAR

Rai

n R

ate

Con

trib

utio

n (%

)

NMQ/Q2 RR>10mm/h 1<RR<10mm/h RR<1mm/h

� Higher contribution for Q2 in the high intensity domain (RR> 10mm/h)���� Increased ability to resolve short lived intense precipita tion

events (thunderstorms, convective events …)

ERAD 2012 25-29 June, Toulouse

Diurnal Cycle : RG and NMQ

Win

ter

Sum

mer

0.00

0.04

0.08

0.12

0.16

0.20

0 6 12 18 24

Aver

age

RR

(m

m/h

)

Time (LST)

RG : DJF

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 6 12 18 24

Aver

age

RR

(m

m/h

)

Time (LST)

RG : JJA

0.00

0.04

0.08

0.12

0.16

0.20

0 6 12 18 24

Aver

age

RR

(m

m/h

)

Time (LST)

NMQ : DJF

RG_DJF=2.21 mm/day NMQ_DJF=2.11 mm/day

RG_JJA=3.78 mm/day NMQ_JJA=3.66 mm/day

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 6 12 18 24

Aver

age

RR

(m

m/h

)

Time (LST)

NMQ : JJA

NMQ_JJA=3.66 mm/day

ERAD 2012 25-29 June, Toulouse

Conclusion and Future WorkPRECIPITATION FEATURES AT HIGH RESOLUTION (NMQ/Q2) :

1. Good agreement between average RR derived from Q2 and 3B42 (+8% yearly)

2. Higher inter-seasonal differences for the PDFs derived from NMQ than 3B42.

3. Important local differences due to beam blockage over the mountains. Necessity of a

global MULTI-SENSOR approach to assess reliable precipitation estimates

FUTURE WORK: REANALYSIS

1.Extend the current domain of study to

32 radars and the entire CONUS

2.Improve artifact identification/removal

(Beam Blockage, AP, …)

3.Incorporate rain gauge measurements

to adjust Q2 rain accumulation (RG

adjusted products)

FUTURE WORK: COMPARISON

1. Impact of T/S resolution on

precipitation features

2. Diurnal Cycle at fine scale

3. Precipitation Types (Stra/Conv)

4. Precipitation Phases (Liquid/Frozen)

5. PDFs (low/extremes RR)

This work is supported by the Cooperative

Agreement NOAA Grant NA09NES4400006