Lakshmi Kantha University of Colorado, Boulder

Sixth FORMOSAT/COSMIC Data Users’ Workshop at NCAR October 30, 2012

TURBULENCE LOCATIONS AND INTENSITIES FROM RADIO OCCULTATION SOUNDINGS

2

Turbulence in the Free Atmosphere Gage et al. (1980)

3

Education and Outreach

COSMIC RO soundings

Radiosonde soundings

4

Unstable Overturning Regions

V ~ 5m/s

Radiosonde

AL

TIT

UD

E

POTENTIAL TEMPERATURE

Unstable

Overturning

Region

Thorpe’s Sorting Algorithm

SORTING ALGORITHM4

1 2

34

5

67

8

9

1011

1213

14

15Z

6

5

127

4

11

83

10

9

Displacement d = Δz

Thorpe scale

LT = rms d1dn( )

Ozmidov scale

LO = ε / N 3

LO

~ LT

→ ε =CKLT

2N

3

CK

~O(1)

Mixing coefficient

K = γεN −2

Mixing efficiency γ ~ 0.25

6

2 sec (~ 10 m) FASTEX Radiosonde Soundings in 1997 Clayson and Kantha (2008)

εεεε

7

6 sec (~ 30 m) Operational Soundings at Denver in 2005 Clayson and Kantha (2008)

ε

Resolution, Resolution, Resolution

1 sec (~ 2 m) SAMS (Balsley et al. 2010) Soundings Kantha (2012)

ε

Effect of Vertical Resolution on extractions (Kantha 2012)

ε

ε

Blue - 2 m, Green – 10 m, Red – 30 m

ε =CKLT

2N3→

11

Harrow (Canada) ST Radar (Kantha & Hocking 2011)

ε = 0.6δ2N

δ −Corrected Spectral Width

Sondes – Red open circles Red lines Radar – Filled circles, Blue lines

12

COSMIC RO Sounding (UTC 23:33 on Dec 30, 2008)

ε

13

Average between Flight Levels 8 and 12 km on July 1, 2010

εεεε

ε

14

at Various Flight Levels at 08:00 UTC on July 1, 2010 ε

Flight Track of AF447 Through Convective Storm Cluster in the ITCZ

* From Final report

AF 447 Crash Site Temperature profiles and TKE Dissipation Rates

Temperature profiles

Red – Dry temperature, Blue – Temperature orrected for water vapor)

17

Aberystwyth (Wales) 50 MHz MST Radar

TKE Dissipation Rates in 1o x 1o box around Wales MST Radar

Comparison with Wales ST Radar

UTC 11:52 on April 19, 2008 NERC radar data from Dr. David Hooper

Comparison with Wales ST Radar

UTC 11:52 on April 19, 2008

ε = 0.6δ2N

ε = 0.6δ2N

•  Extraction of turbulence locations and intensities from GPS/GNSS RO soundings feasible

•  More cal/val is needed – ST/MST radars can help here. PIREPS too •  Combined with high-res radiosondes, the technique can help

understand the spatio-temporal variability of mixing in the global free atmosphere

•  Potential operational utility for aviation applications •  Complements refractive index fluctuation spectrum approach by

Cornman et al. at NCAR •  Looking forward to COSMIC follow-on projects and operational use

Concluding Remarks

QUESTIONS?

Acknowledgements: COSMIC Project and NCAR for RO soundings Dr. Clayson (WHOI) for assistance with data

•  Clayson, C. A. and L. Kantha (2008). On turbulence and mixing in the free atmosphere inferred from high-resolution soundings. J. Atmos. Ocean. Technol., 25, 833–852. •  Balsley, B. B., Kantha, L. & Colgan, W. (2010). On the use of Slow Ascent Meter-Scale Sampling (SAMS) radiosondes for observing overturning events in the free atmosphere. J. Atmos. Oceanic Technol., 27, 766-775. •  Kantha, L. & Hocking, W. (2011). Dissipation rates of turbulence kinetic energy in the free atmosphere: MST radar and radiosondes. J. Atmos. Sol. Terr. Phys., 73, 1043-1051. •  Kantha, L. (2012). Turbulence dissipation rates in the free atmosphere from high-resolution radiosondes. In Turbulence: Theory, Types and Simulation, Chapter 7, NOVA Science Publishers, 239-264. •  Kantha, L. (2012b). Turbulence locations and intensities in the atmosphere from radio occultation soundings. Unpublished manuscript.

References