Laura B. Sheard HHS Public Access 1,* Xu Tan1,*,† Haibin ...
Xiaodong Tang , Zhe-Min Tan1, Juan Fang , Y. Qiang Sun ...
1
Impact of the Diurnal Radiation Cycle on Secondary Eyewall Formation Xiaodong Tang 1 , Zhe-Min Tan 1 , Juan Fang 1 , Y. Qiang Sun 2 , and Fuqing Zhang 2 1 School of Atmospheric Sciences, Nanjing University, China; 2 Department of Meteorology, The Pennsylvania State University, USA 16/18 16/06 15/18 14/18 15/06 UTC 16/18 16/06 15/18 14/18 15/06 UTC (a) (b) (c) (d) [dBZ] 10 m s -1 Control NoSolarRad (b) (c) 2100 UTC 16 Sep C 16 Sep T 2100 U T T C 15 17 20 22 25 27 30 32 35 37 40 42 45 47 [dBZ] Observation (a) 2008 UTC 16 Sep Control NoSolarRad [m s -1 ] [m s -1 ] (a) (d) (b) (e) (c) (f) Vt @ z = 1 km Vr @ z = 1 km Vr @ z = 2 km 17/12 17/00 16/12 16/00 15/12 15/00 14/12 UTC 17/12 17/00 16/12 16/00 15/12 15/00 14/12 UTC SEF Figure 1: Composite radar reflecvity from (a) aircraſt reconnaissance into Hurricane Edouard (2014), and (b) CNTL, and (c) NoSolarRad at a height of 5 km. Red arrows denote vercal shear vectors of averaged environmental wind. Figure 2: Hovmöller plots of azimuthal-mean tangenal velocity at a height of 1 km and radial velocity at heights of 1 and 2 km for (a)–(c) CNTL and (d)–(f) NoSolarRad. The superposed black lines denote the RMW at 1 km. Figure 3: Hovmöller plots of azimuthal mean vercal velocity at heights of 6 and 2 km for (a)–(b) CNTL and (c)–(d) NoSolarRad. The vercal red lines show key radial distances. Figure 5: Evoluon of (a) 2-m temperature, (b) MCAPE, (c) 10-m wind speed, and surface fluxes of (d) latent heat and (e) sensible heat averaged between 60 and 75 km radius for CNTL and NoSolarRad. Figure 4: Height–me plot of NoSolarRad minus CNTL di fference of (a) shortwave radiave heang, (b) longwave radiave heang, (c) net radiave heang, and (d) latent heang between 60 and 75 km radius from 1300 UTC 14 September to 1800 UTC 16 September 2014. The units are 10 –5 K/s for (a)–(c) and 10 –3 K/s for (d). • Heated surface air weakens WISHE feedback between the surface fluxes (that promote convection) and convective heating (that feeds into the secondary circulation and then the tangential wind). • The net radiative heating in CNTL is much stronger due to the solar insolation at daytime. • Less conducive for deep moist convection in CNTL • Less diabatic heating due to suppressed convection in CNTL • Difference: 0.5–1 K/day at the top of the boundary layer 4. Radia ve e ffects on SEF 4.1 Moat formaon 4.2 Balanced aspects of SEF 3. Overview of the SEF of Hurricane Edouard (2014) 3.2 Evoluon of vercal velocity (Fig. 3) 3.1 Evoluon of boundary layer wind (Fig. 2) Control NoSolarRad z = 6 km z = 2 km (a) (b) (c) (d) [m s -1 ] -1 -0.5 -0.25 -0.05 0.1 0.2 0.5 1 1.5 2 2.5 3 17/12 17/00 16/12 16/00 15/12 15/00 14/12 17/12 17/00 16/12 16/00 15/12 15/00 14/12 UTC UTC inner rainbands moat • The latent heating released from more convective activities in the inner rainbands outside of primary eyewall in NoSolarRad • The outer-core (outside the radius of 150 km) upward motion at mid-level in CNTL became more organized, and began to move inward • Clear moat formation and SEF Moat region is highly sensitive to the solar shortwave radiative heating mostly in the mid- to upper-level at daytime, which leads to a net stabilization effect and suppresses convective development. The heated surface air weakens WISHE feedback between the surface fluxes (that promote convection) and convective heating (that feeds to the secondary circulation and then the tangential wind). NoSolarRad: without solar radiation, active inner rainband, suppressed primary eyewall, no moat, no SEF The radiation-induced absence of latent heating is more important on moat formation in the early stage of SEF . 1. Introducon • Secondary eyewall formaon (SEF) is a key issue for TC research and forecas ng, as it is closely related to both short-term TC intensity change and TC size change. • We demonstrated the impacts of radiaon on the size and strength of the mature hurricane Edouard (2014) (Tang and Zhang 2016). • The mechanism by which the solar insolaon affects SEF remains unexplored, and this is the focus of the current study. 2. Experimental setup Control run (CNTL): • Real diurnal cycle; Hurricane Edouard; integrated from 1200 UTC 11-Sep-2014 Sensivity experiments: • No solar insolaon ( NoSolarRad); starng at 72 model integraon hours of CNTL The crical differences between CNTL and NoSolarRad are the stronger inner rainbands and the lack of a clear moat region in NoSolarRad. CNTL: The double maximum inflow (oulow) regions at the 1-km (2-km) level formed at ~1200 UTC 16 September (Fig. 2b, c). CNTL: The secondary maximum of the tangen al winds formed at ~1800 UTC 16 September (Fig. 2a). NoSolarRad: Heang from stronger inner rainbands outside the RMW in the midtroposphere increasing (reducing) low-level tangen al wind outside (near and inside) the RMW outward expansion of the RMW (Fig. 2d). NoSolarRad: The maximum radial inflow was farther out from the RMW during the period from 1800 UTC 15 September to 0600 UTC 16 September (Fig. 2e), without a con nuous secondary maximum of 2-km oulow (Fig. 2f). Figure 6: Radius–height cross-secons of the 2-hour azimuthal-mean of the ineral stability parameter I 2 (shading) and latent heang (blue contours, unit: 10 –3 K/s) from WRF output in (a) CNTL and (d) NoSolarRad, and of ver cal velocity (shading), radial velocity (red contours, unit: m/s), and the combined contribuon of radial advecon of absolute vorcity and vercal advec on of tangenal wind to the tangenal wind tendency (green contours, 10 –3 ms –2 ) from Sawyer-Eliassen model calculaons using (b) the background vortex structure and diabac hea ng from CNTL, (c) the background vortex structure of CNTL, diabac heang from NoSolarRad, (e) the background vortex structure and diaba c heang from NoSolarRad, and (f) the background vortex structure of NoSolarRad and diabac heang from CNTL. The period is from 0500 to 0700 UTC 16 September 2014. [m s -1 ] (c) (b) (f) vortex: CNTL latent heating: CNTL vortex: CNTL latent heating: NoSolarRad vortex: NoSolarRad latent heating: NoSolarRad vortex: NoSolarRad latent heating: CNTL (e) [10 -7 s -2 ] CNTL WRF SE WRF NoSolarRad SE SE SE (a) (d) (W m -2 ) Sensible Heat Flux (W m -2 ) (a) (b) (d) (c) (e) 16/12 16/00 15/12 15/00 14/12 UTC 16/12 16/00 15/12 15/00 14/12 UTC short wave long wave net radiation latent heat Radial wind Tangenal wind • Tang, X., and F. Zhang, 2016: Impacts of the Diurnal Radiaon Cycle on the Formaon, Intensity and Structure of Hurricane Edouard (2014), J. Atmos. Sci., 73, 2871-2892. • Tang, X. et al, 2017: Impact of the Diurnal Radiaon Cycle on Secondary Eyewall Forma on, J. Atmos. Sci., In press 6. Further reading 5. Concluding remarks
Transcript of Xiaodong Tang , Zhe-Min Tan1, Juan Fang , Y. Qiang Sun ...
Impact of the Diurnal Radiation Cycle on Secondary Eyewall FormationXiaodong Tang1, Zhe-Min Tan1, Juan Fang1, Y. Qiang Sun2, and Fuqing Zhang2
1 School of Atmospheric Sciences, Nanjing University, China; 2 Department of Meteorology, The Pennsylvania State University, USA
16/1816/0615/1814/18 15/06UTC
16/1816/0615/1814/18 15/06UTC
(a) (b)
(c) (d)
[dBZ] 10 m s-1
Control NoSolarRad
(b) (c)
2100 UTC 16 SepC 16 SepT2100 UTTC
15 17 20 22 25 27 30 32 35 37 40 42 45 47 [dBZ]
Observation
(a)
2008 UTC 16 Sep
Control
NoS
olarRad
[m s-1][m s-1]
(a)
(d)
(b)
(e)
(c)
(f)
Vt @ z = 1 km Vr @ z = 1 km Vr @ z = 2 km 17/12
17/00
16/12
16/00
15/12
15/00
14/12
UTC
17/12
17/00
16/12
16/00
15/12
15/00
14/12
UTC
SEF
Figure 1: Composite radar reflectivity from (a) aircraft reconnaissance into HurricaneEdouard (2014), and (b) CNTL, and (c) NoSolarRad at a height of 5 km. Red arrowsdenote vertical shear vectors of averaged environmental wind.
Figure 2: Hovmöller plots of azimuthal-mean tangential velocity at a height of 1km and radial velocity at heights of 1 and 2 km for (a)–(c) CNTL and (d)–(f)NoSolarRad. The superposed black lines denote the RMW at 1 km.
Figure 3: Hovmöller plots of azimuthal mean vertical velocity at heights of 6 and 2km for (a)–(b) CNTL and (c)–(d) NoSolarRad. The vertical red lines show key radialdistances.
Figure 5: Evolution of (a) 2-m temperature, (b) MCAPE, (c) 10-m wind speed, andsurface fluxes of (d) latent heat and (e) sensible heat averaged between 60 and 75 kmradius for CNTL and NoSolarRad.
Figure 4: Height–time plot of NoSolarRad minus CNTL difference of (a) shortwaveradiative heating, (b) longwave radiative heating, (c) net radiative heating, and (d)latent heating between 60 and 75 km radius from 1300 UTC 14 September to 1800UTC 16 September 2014. The units are 10–5 K/s for (a)–(c) and 10–3 K/s for (d).
• Heated surface air weakens WISHE feedback between the surface fluxes (that promote convection) and convective heating (that feeds into the secondary circulation and then the tangential wind).
• The net radiative heating in CNTL is much stronger due to the solar insolation at daytime.
• Less conducive for deep moist convection in CNTL
• Less diabatic heating due to suppressed convection in CNTL
• Difference: 0.5–1 K/day at the top of the boundary layer
4. Radiative effects on SEF4.1 Moat formation 4.2 Balanced aspects of SEF
3. Overview of the SEF of Hurricane Edouard (2014)
3.2 Evolution of vertical velocity (Fig. 3)
3.1 Evolution of boundary layer wind (Fig. 2)
Control
NoS
olarRad
z = 6 km z = 2 km (a) (b)
(c) (d)
[m s-1]-1 -0.5 -0.25 -0.05 0.1 0.2 0.5 1 1.5 2 2.5 3
17/12
17/00
16/12
16/00
15/12
15/00
14/1217/12
17/00
16/12
16/00
15/12
15/00
14/12
UTC
UTC
inner rainbands
moat
• The latent heating released from more convective activities in the inner rainbands outside of primary eyewall in NoSolarRad
• The outer-core (outside the radius of 150 km) upward motion at mid-level in CNTL became more organized, and began to move inward
• Clear moat formation and SEF
Moat region is highly sensitive to the solar shortwave radiative heating
mostly in the mid- to upper-level at daytime, which leads to a net
stabilization effect and suppresses convective development.
The heated surface air weakens WISHE feedback between the surface
fluxes (that promote convection) and convective heating (that feeds to
the secondary circulation and then the tangential wind).
NoSolarRad: without solar radiation, active inner rainband,
suppressed primary eyewall, no moat, no SEF
The radiation-induced absence of latent heating is more important on
moat formation in the early stage of SEF.
1. Introduction• Secondary eyewall formation (SEF) is a key issue for TC research andforecasting, as it is closely related to both short-term TC intensity change and TCsize change.• We demonstrated the impacts of radiation on the size and strength of themature hurricane Edouard (2014) (Tang and Zhang 2016).• The mechanism by which the solar insolation affects SEF remains unexplored,and this is the focus of the current study.
2. Experimental setup Control run (CNTL):• Real diurnal cycle; Hurricane Edouard; integrated from 1200 UTC 11-Sep-2014 Sensitivity experiments: • No solar insolation (NoSolarRad); starting at 72 model integration hours of CNTL
The critical differences between CNTL and NoSolarRad are the stronger inner rainbands and the lack of a clear moat region in NoSolarRad.
CNTL: The double maximum inflow (outflow) regions at the 1-km (2-km) levelformed at ~1200 UTC 16 September (Fig. 2b, c).CNTL: The secondary maximum of the tangential winds formed at ~1800 UTC16 September (Fig. 2a).NoSolarRad: Heating from stronger inner rainbands outside the RMW in themidtroposphere increasing (reducing) low-level tangential wind outside (nearand inside) the RMW outward expansion of the RMW (Fig. 2d).NoSolarRad: The maximum radial inflow was farther out from the RMW duringthe period from 1800 UTC 15 September to 0600 UTC 16 September (Fig. 2e),without a continuous secondary maximum of 2-km outflow (Fig. 2f).
Figure 6: Radius–height cross-sections of the 2-hour azimuthal-mean of the inertialstability parameter I2 (shading) and latent heating (blue contours, unit: 10–3 K/s)from WRF output in (a) CNTL and (d) NoSolarRad, and of vertical velocity(shading), radial velocity (red contours, unit: m/s), and the combined contributionof radial advection of absolute vorticity and vertical advection of tangential windto the tangential wind tendency (green contours, 10–3 m s–2) from Sawyer-Eliassenmodel calculations using (b) the background vortex structure and diabatic heatingfrom CNTL, (c) the background vortex structure of CNTL, diabatic heating fromNoSolarRad, (e) the background vortex structure and diabatic heating fromNoSolarRad, and (f) the background vortex structure of NoSolarRad and diabaticheating from CNTL. The period is from 0500 to 0700 UTC 16 September 2014.
[m s-1]
(c)(b)
(f)
vortex: CNTL latent heating: CNTL vortex: CNTL latent heating: NoSolarRad
vortex: NoSolarRad latent heating: NoSolarRad vortex: NoSolarRad latent heating: CNTL
(e)
[10-7 s-2]
CNTLWRF SE
WRF NoSolarRad SE
SE
SE
(a)
(d)
(W m-2) Sensible Heat Flux (W m-2)
(a) (b)
(d)
(c)
(e)
16/12
16/00
15/12
15/00
14/12
UTC
16/12
16/00
15/12
15/00
14/12
UTC
short wave long wave
net radiation latent heat
Radial windTangential wind
• Tang, X., and F. Zhang, 2016: Impacts of the Diurnal Radiation Cycle on the Formation,Intensity and Structure of Hurricane Edouard (2014), J. Atmos. Sci., 73, 2871-2892.• Tang, X. et al, 2017: Impact of the Diurnal Radiation Cycle on Secondary Eyewall Formation, J.Atmos. Sci., In press
6. Further reading
5. Concluding remarks
![Pengakuan Dosa [Sopir] A[ng]ku[n]tan1 Pendidik: Studi ...](https://static.fdocuments.in/doc/165x107/61ec3535383440288507477f/pengakuan-dosa-sopir-angkuntan1-pendidik-studi-.jpg)
