the rapid intensification of hurricane karl (2010): insights from new remote sensing measurements...
TRANSCRIPT
The Rapid Intensification of Hurricane Karl (2010): Insights from New Remote Sensing
Measurements
Collaborators:Anthony Didlake (NPP/GSFC) ,Gerry Heymsfield (GSFC), Paul
Reasor (HRD)
Steve Guimond (UMD/GSFC)
Outline
• Brief background on datasets used (HIWRAP, HAMSR, P3 TA) and Karl case.
• HIWRAP processing– 3DVAR wind retrieval algorithm– Error characteristics
• flight-level data comparisons from HS3/NOAA coordination (2013)
• Understanding of Karl’s RI with remote sensing data– Answers to questions from HS3 inner-core part of proposal
• What is role of convective bursts in intensification? • How do convective bursts form?• Does warm-core development depend on bursts?
Remote Sensing Instruments
600 – 700 m (along-track) 150 m (gate spacing)
1 km retrieval products
HIWRAP HAMSRFrom JPL
NOAA P3 TA Radar
Sensitive to Temp & Precipitation ~ 2 km resolution, ~ 60 km swath width
From NOAA
X-band large coverage area
2 km retrieval products
3D Least Squares and Variational Methods:
Values of coefficients found by tuning to simulated and in situ data.
Nonlinear minimization
HIWRAP: Atmospheric Wind RetrievalsGuimond et al. (2014) J. Atmos. Oceanic Technol., 31, 1189-1215.
HS3 Coordinated Flight with P3 (2013)
Quality controlled Keep data with time offset < 10 min, space offset < 1 km, dBZ > 5 N = ~ 5000 Ka band retrievals have slightly lower mean errors
Recommendation: use Ku band retrievals where dBZ > ~ 20 – 25 and Ka belowAll science results in this work use this partitioning
HS3 Coordinated Flight with P3 (2013)
HIWRAP on Global Hawk Detects Karl (2010) Rapid Intensification
9/16 ~ 19 UTC – 9/17 08 UTC
From NHC…16 / 18 UTC 982 hPa 36 m/s hurricane
17 / 00 UTC 971 hPa 44 m/s 17 / 06 UTC 966 hPa 49 m/s 17 / 12 UTC 956 hPa 57 m/s
HIWRAP on Global Hawk Detects Karl (2010) Rapid Intensification
9/16 ~ 19 UTC – 9/17 08 UTC
From NHC Global Hawk Observations
Warm SSTs
Low wind shear
1845 Z 2215 Z
0145 Z 0600 Z
NRL
HIWRAP Time Mean Structure Ku Band Time Mean (12 – 13 h) Reflectivity and Wind Vectors
Only inner beam functional (~ 20 km swath width @ surface)
Deep convective towers down shear to down shear left (well known). Very active pulsing for ~ 6 h between (~ 1800 – 0000 UTC).
~ 5 m/s
2 km 8 kmStrongest Winds
Structure of Inner-Core: Pass 1 (1853–1919 UTC) 2 km height in down-shear left quadrant
30 – 40 m/s
10 – 20 m/s
Structure of Inner-Core: Pass 1 (1853–1919 UTC) 2 km Height
Attenuation from bursts
Structure of Inner-Core: Pass 1 (1853–1919 UTC)
Eye-Eyewall Interaction
10 – 15 m/s radial flow~ 10 m/s updraft
Structure of Inner-Core: Pass 2 (1938–1957 UTC) 2 km height in down/up-shear left quadrant
Structure of Inner-Core: Pass 2 (1938–1957 UTC)
Ku band reflectivity at nadir
center
Structure of Inner-Core: Pass 2 (1938–1957 UTC)
Storm-relative radial wind at nadir
Structure of Inner-Core: Pass 2 (1938–1957 UTC)
Vertical wind at nadir
Convective induced descent
Structure of Inner-Core: Pass 3 (2009–2055 UTC)
30 – 40 m/s
10 – 20 m/s
2 km height in down-shear direction
20 – 30 m/s
~ 40 m/s
Structure of Inner-Core: ~2040 & 2042 UTC
HIWRAP
NOAA TA
Reflectivity comparison
HIWRAP
NOAA TA
outflow
outflowinflow
inflow
Storm relative radial wind comparison
Structure of Inner-Core: ~2040 & 2042 UTC
HIWRAP
NOAA TAEdge downdraft
Edge downdraft
Vertical wind comparison
Structure of Inner-Core: ~2040 & 2042 UTC
HIWRAP
NOAA TASpin-up
Spin-up
Tangential wind comparison
Structure of Inner-Core: ~2040 & 2042 UTC
Convective TowersHIWRAP Time Series
HAMSR54 GHz750 hPa
Courtesy of JPL GRIP PORTAL
Science Discussion• GRIP inner-core data indicates…1) Convective bursts forming through transport & converg. of
warm anomaly air from eye to eyewall.2) Turbulent mixing between eye/eyewall and convective
descent responsible for carving out eye and intensifying warm core locally (large asymmetric component).
3) Axisymmetric and asymmetric projection of burst heating leads to symmetric vortex response, which includes symmetric intensification of warm core at later times.
4) Convective bursts are important for RI Builds on prior work (Heymsfield et al.,Reasor et al., Molinari et
al., Guimond et al., Rogers et al., Montgomery et al., Braun et al., etc…)
Guimond et al. (2015) JAS, in preparation.
Acknowledgements• Thanks to HIWRAP engineers– Matt McLinden, Lihua Li, Martin Perrine, Ed Zenker,
Jaime Cervantes, Michael Coon• Thanks to HAMSR engineers for L1 data• Thanks to HS3 PIs (Scott Braun/Paul Newman)
HS3 Coordinated Flight Quality controlled
Keep data with time offset < 10 min, space offset < 1 km, dBZ > 5 N = ~ 5000 Ka band retrievals have slightly lower mean errors
Recommendation: use Ku band retrievals where dBZ > ~ 20 – 25 and Ka below
HIWRAP: Atmospheric Wind Retrievals
Traditional Least Squares Method (Guimond et al. 2014):
min
γ = 0.75, β = 6 For HIWRAP δ = ~ 3 – 4 km @ sfc, ~ 1 km @ 15 km height
FREE PARAMETERS
HIWRAP: Atmospheric Wind Retrievals
HIWRAP on Global Hawk Detects Karl (2010) Rapid Intensification
9/16 ~ 19 UTC – 9/17 08 UTC
From NHC
Error Characteristics Simulated errors:
~ 2.0 m/s for horizontal winds, ~ 1.0 m/s or less for vertical winds Function of cross-track location: best at nadir.
In situ (NOAA P3 flight-level winds) errors: IWRAP data (~ 7 % for horizontal winds, ~ 2.0 m/s for vertical winds) HIWRAP data (9/25/2013 coordinated flight with NOAA43 during HS3)
See Guimond et al. (2014) for simulated and in situ (IWRAP) error characteristics
Structure of Inner-Core: Pass 3 (2009–2055 UTC)
center
Ku band reflectivity at nadir
Structure of Inner-Core: Pass 3 (2009–2055 UTC)
Convective descent weaker burst in “blow up” stage
Vertical wind at nadir
Structure of Inner-Core: Pass 3 (2009–2055 UTC)
Storm-relative radial wind at nadir
Warm anomaly air
Significant eye-eyewall interaction
Strong outflow