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Transcript of 1 James D. Doyle 1, Hao Jin 2, Clark Amerault 1, and Carolyn Reynolds 1 1 Naval Research Laboratory,...
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James D. Doyle1, Hao Jin2, Clark Amerault1, and Carolyn Reynolds1
1Naval Research Laboratory, Monterey, CA2SAIC, Monterey, CA
James D. Doyle1, Hao Jin2, Clark Amerault1, and Carolyn Reynolds1
1Naval Research Laboratory, Monterey, CA2SAIC, Monterey, CA
NRL Mesoscale Model Adaptive Observing during T-PARC/TCS08NRL Mesoscale Model Adaptive
Observing during T-PARC/TCS08
•Global-model adjoint tools (mostly dry) have been applied to TC track•Adjoints have not been applied to TC genesis systematically
-Forecasts of genesis are often poor (e.g., T-PARC/TCS08)• Is targeting for TC genesis feasible (T-PARC/TCS08)?
•Global-model adjoint tools (mostly dry) have been applied to TC track•Adjoints have not been applied to TC genesis systematically
-Forecasts of genesis are often poor (e.g., T-PARC/TCS08)• Is targeting for TC genesis feasible (T-PARC/TCS08)?
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COAMPS Adjoint SensitivityCOAMPS Adjoint Sensitivity
J: response function xi: state vector at initial time ti xt: state vector at final time tf
MT: adjoint of non-linear model, M
Sensitivity of the response function at final time tf
to the initial (or model forecast) state at time ti
T
i f
J JM
x x
Adjoint-Based “Optimal” Perturbations
jj j
s Jx
w x
wj: weighting parameter s: scaling parameter (umax~1 m s-1)
Adjoint Allows for the Mathematically Rigorous Calculation of Forecast Sensitivity
COAMPS® Nonlinear, Adjoint, Tangent Linear Model Setup• x=40 km, 18 h (18 h lead time) (real time 24 h with 24, 36, 48-h lead times)• x=10 km, 9 h (15 h lead time) (not shown here)• PBL, Surface Flux, Microphysics (no ice)• J: Kinetic Energy in a Box (lowest 1 km)
Adjoint Sensitivity for 14 West Pacific Genesis Events (5 Super Typhoons)
• Fitow, Man-Yi, Krosa, Sepat, Trami, Wipha, Yutu (Pre- T-PARC/TCS08)• Nuri, Sinlaku, Hagupit, Jangmi, Higos, TCS025, 16W (T-PARC/TCS08)
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COAMPS Forecasts during T-PARC / TCS-08COAMPS Forecasts during T-PARC / TCS-08
• Real-Time COAMPS Adjoint for Targeting Guidance.
• 40 km resolution for 24-h, 36-h, 48-h lead times.
• Adaptive response function box.
• Real-Time COAMPS-TC 72-h Forecasts with Moving Meshes.
• 45/15/5 km horizontal resolution.
AdjointSensitivity
C130 Flight Track
COAMPS radar reflectivity every 30 minutes on 5 km moving grid
COAMPS Track (red) & Official Warning Positions (black) (12 h)
24h959mb
48h/916mb
72h/913mb
24h/925mb
48h/916mb
72h/985mb
0h0h
24h959mb
48h/916mb
72h/913mb
24h/925mb
48h/916mb
72h/985mb
0h0h
Jangmi
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QScat
ssmi.com
QScat
ssmi.com
Nonlinear Model EvolutionTropical Cyclone Fitow (Pre- T-PARC)
Nonlinear Model EvolutionTropical Cyclone Fitow (Pre- T-PARC)
18-h 10-m Winds & SLP (0-h Adjoint)
1000 mb1000 mb1004 mb1004 mb
ResponseFunction Area
ResponseFunction Area
• Nonlinear model captures monsoon gyre and asymmetric structure• Adjoint sensitivity computed during early development phase (18-36 h)
36-h 10-m Winds & SLP (18-h Adjoint)
• Asymmetric structure
• 18-h adjoint sensitivity (06Z 29 - 00Z 30 Aug ‘07)
> 35 kts
Best Track
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Sensitivity FieldsMoisture & Potential Temperature
Sensitivity FieldsMoisture & Potential Temperature
36-h KE sensitivity to 18-h state
Banded Sensitivity StructuresKE/(4 km)KE/qv 500 m
KE/qv KE/
Low-Level Moisture
Sensitivity
Mid-Level Sensitivity
e Perturbation
W E W E W E
Low-Level e Maximum
(Destabilization)
• Preferred regions of large sensitivity to low-level moisture and .• Low-level e optimal perturbations: destabilize & saturate core.
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2
0
27TLM Optimal U’ at 500 m
18h (re-scaled at 3h)10-m Wind Speed Pert.
23 m s-1
Umax=39 m s-1•Rapid Growth •Eye Structure
Tangent Linearu’ at 500 m
24 m s-1
Evolved Adjoint-Based PerturbationsPerturbation Winds
Evolved Adjoint-Based PerturbationsPerturbation Winds
correlation ~ 0.5
Evolved 18 h
Nonlinearu’ at 500 m
24 m s-1
• Evolved perturbations in TLM and NLM are well correlated.• Rapid growth over 18 h: Usfc=23 m s-1, psfc=-8 hPa,
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T-PARC/TCS08 Real-Time Adjoint ForecastsTC Sinlaku
T-PARC/TCS08 Real-Time Adjoint ForecastsTC Sinlaku
54-h KE sensitivity to 36-h state
• Vorticity sensitivity bands that are anticyclonically curved.• Strongest sensitivity to low- and mid-level and qv.• C130 sampled key portions of the sensitivity.
24-h adjoint sensitivity 36-h lead time
Valid at 12Z 10 Sep 2008
2-km vorticity sensitivity Total energy sensitivity
C130 Flight Track
C130 Flight Track
DropsondesDropsondes
Best Track
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T-PARC/TCS08 Real-Time Adjoint ForecastsTC Jangmi
T-PARC/TCS08 Real-Time Adjoint ForecastsTC Jangmi
54-h KE sensitivity to 36-h state
• Vorticity sensitivity shows a wave packet pattern.• The and qv sensitivity have multiple maxima over a broad area.• C130 sampled only a small portion of the sensitivity.
24-h adjoint sensitivity 36-h lead time
Valid at 00Z 25 Sep 2008
2-km vorticity sensitivity Total energy sensitivity
Best Track
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T-PARC/TCS08 Real-Time Adjoint ForecastsTC Jangmi
T-PARC/TCS08 Real-Time Adjoint ForecastsTC Jangmi
54-h KE sensitivity to 36-h state
• SST sensitivities were computed in real time.• The SST sensitivity often showed complex patterns.• C130 deployed many AXBTs during T-PARC/TCS08.
SST Valid at 00Z 25 Sep 2008 Surface temperature (SST) sensitivity
LL
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Genesis Sensitivity FieldsTC Nuri (T-PARC/TCS08)
Genesis Sensitivity FieldsTC Nuri (T-PARC/TCS08)
36-h KE sensitivity to 18-h state
KE/ (0.5 km) & SLP (18 h)
Vortex Structure
Evolved Optimal U’ (18-36 h)
12 m s-1
•Rapid Growth •Eye Structure
18-h adjoint sensitivity (06Z 15 Aug - 00Z 16 Aug 2008)
Low-Level e Max. Tilted
Against Shear
KE/e (18 h)
W E• Large sensitivity to radial vorticity gradient.• The qv and sensitivities are 3-4x greater than u sensitivity.• Optimal e perturbations destabilize & saturate core.
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Perturbation Energy CharacteristicsSummary of 16 Cases (13 Events)
Perturbation Energy CharacteristicsSummary of 16 Cases (13 Events)
Initial PerturbationDomain Average of Optimal
Perturbations Evolved in TLM
• Initial total energy maximum in low-levels (bottom up).• Deep perturbation growth throughout troposphere.• Non-developers show weakest growth.
Final Perturbation (18 h)
Upper-Level Max. Consistent With
Background
Deep Response Function Box is
Consistent
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ConclusionsConclusions
•Adjoint sensitivity characteristics for TC genesis & intensification.-Low-level maxima suggestive of bottom-up progression.-Preferred regions of moistening, destabilization, & vorticity bands.-Broad SST sensitivity regions linked to convection.-TL approximation is accurate for TCs considered (with moisture).
• Predictability of tropical cyclogenesis.-Low predictability (500-m winds: 50% cases show > 10x growth 18 h-1).-Sensitivity structures (particularly qv and ) may be observable.
• Future Directions-Higher resolution sensitivity calculations.-Data denial and targeting experiments based on T-PARC / TCS08.
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Genesis Sensitivity FieldsTC025 (Non-Developer)
Genesis Sensitivity FieldsTC025 (Non-Developer)
36-h KE sensitivity to 18-h state
• Non-developers show slow growth, weaker sensitivity to qv and .• Greater sensitivity to vertical shear.
KE/ (0.5 km) & SLP (18 h)
No Vortex Structure
Evolved Optimal U’ (18-36 h)
3 m s-1
•Slow Growth •4x Slower than Nuri
4x Weaker than Nuri
KE/e (18 h)
W E W E
Sensitive to Shear
KE/u (18 h)
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Dry and Moist Sensitivity ComparisonGradients and Evolved Perturbations
Dry and Moist Sensitivity ComparisonGradients and Evolved Perturbations
KE/u5 km
6.9x10-3 m s-1
Moist
KE/u5 km
-3.1x10-4 m s-1
Dry
• Moist shows faster growth (>10x) and smaller scale than dry adjoint.• Dry processes organize large-scale, moist processes dominate growth.
Evolved p’sfc
-8 hPa-5 hPa SLP Min.
Moist
-0.3 hPa
Evolved p’sfc
Dry
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SST Sensitivity FieldsTropical Cyclones Fitow and Wipha
SST Sensitivity FieldsTropical Cyclones Fitow and Wipha
36-h KE sensitivity to 18-h state
Fitow Wipha
KE/SST KE/SST
Sensitivity of 36-h KE to 18-h SST
• Sensitivity to SST maximum near TC core & along track (asymmetry).• SST perturbations over 18 h (1°C max.) suggest pre-WISHE stage.
-Fitow: -0.75 hPa and +1.0 m s-1.-Wipha: -0.50 hPa and +1.2 m s-1.
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Sensitivity of Adjoint Results to ResolutionTropical Cyclone Fitow (x=10 km)
Sensitivity of Adjoint Results to ResolutionTropical Cyclone Fitow (x=10 km)
qv perturbation (0-3 km) and SLP (15 h) KE/ (8 km) & SLP (15 h)
• Increase in horizontal resolution from 40 km to 10 km yields similar sensitivity structures and relationships.
• Sensitivity to moistening and warming in low-levels.• Banded vorticity sensitivity structures. • Evolved perturbations: winds~42 m s-1 (9 h), SLP ~ -8 hPa (9 h)
Banded Sensitivity Structures
Correlated and qv
Perturbations
perturbation (0-3 km)
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NOGAPSCOAMPS
(Dry dx=100 km)
NOGAPSCOAMPS
48 h
Total Energy / SLP
Total Energy / SLP
SV: Initial
SV: Final Evolved Perturbations
Initial Sensitivity
Doyle, Amerault, Reynolds
NOGAPS SVs and COAMPS Adjoint ComparisonTropical Cyclone Fitow
NOGAPS SVs and COAMPS Adjoint ComparisonTropical Cyclone Fitow