Remote Sensing Laboratory ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA AVHoTRRA Valerio Lombardo GNV 2007 Progetto Etna

Remote Sensing Laboratory

ISTITUTO NAZIONALE DI GEOFISICA E ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIAVULCANOLOGIA

AVHoTRRAVHoTRRAA

Valerio Lombardo

GNV 2007GNV 2007Progetto EtnaProgetto Etna

ISTITUTO NAZIONALE DI GEOFISICA ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIAE VULCANOLOGIA

(t+t) (t)

Lava Background

Thermal model (Low Resolution)Thermal model (Low Resolution)

•Identification of the thermal anomaly (Alert)

•Dual-band constrains

•The effusion rate estimation

Issues


Available SensorsAvailable Sensors

ASTER29/07/2001

MIVIS29/07/2001

Resolution: 5-8m 30m 1 Km

Acquisition: on demand every 16 day 3-5 per day

AVHRR29/07/2001


the radiance detected by the sensor in one band is an average, weighted by the fractional area, of the two radiances related to the different temperatures (Rothery et al. 1988 ):

RRtottot = f = fhh (R (Rhh) + (1 - f) + (1 - fhh) R) Rcc

RR() = C1C1

5 (exp(C2/ T) - 1)

Planck equation:

Background: dual-band techniqueBackground: dual-band technique

RR22tottot = f = fhh (R (R22

hh) + (1 - f) + (1 - fhh) R) R22c c


hh) + (1 - f) + (1 - fhh) R) R11c c

Dual-band technique:


Dual-band solutions allow for calculation of radiant flux (Qlava) from active flows

QQlavalava = = [ f[ fhh T Thh44 + (1 - f + (1 - fhh) T) Tcc

44 ] ]

EErr = Qtot

lavalava cpcplavalava T+CT+CLL

Effusion rate Er (Pieri and Baloga 1986; Harris et al. 1997):

Background: effusion rateBackground: effusion rate

lavalava: : lava densityCpCplava lava : : specific heat capacityT : T : avarage temperature drop throughout the active lavaCCL L : : latent heat of crystallization: : average mass of crystals grown in cooling through T

Qcon


Methodology

We use 3 bands of the MIVIS dataset as input of the system to obtain simultaneous solutions for the three unknowns: Tc, Th, fh.


hh) + (1 - f) + (1 - fhh) R) R22c c


hh) + (1 - f) + (1 - fhh) R) R11c c


hh) + (1 - f) + (1 - fhh) R) R33c c

1.53 m

2.19 m

11.36 m


IDL routineIDL routinefor effusion rate estimationfor effusion rate estimation


Landsat 5 and 7 data setLandsat 5 and 7 data set

Summary of Landsat ETM sensor parameters.

Temporal Comparison of Thermal and Geometrical Features

• INGV database contains 80 Landsat 5 TM and Landsat 7 ETM images covering Etna activity, during 1984 – 2003 period.

• We applied remote sensing techniques to retrieve the energy flux and effusion rates of active lava flows for each image.


We estimated the energy flux and the effusion rate for every image of our database

TI

ME

1984

2001

1984 – 2001 effusion rate estimates1984 – 2001 effusion rate estimates


Energy flux

0

1,000,000,000

2,000,000,000

3,000,000,000

4,000,000,000

5,000,000,000

6,000,000,000

Time

En

erg

y fl

ux

(Wat

t)

Dual band

Integr.Temp.

1984 – 2001 energy flux1984 – 2001 energy flux

April - October 1984

March - July 1985

Dicember 1991 - March 1993

July - December 1997

March 1998

June - September 1998

Febrary - November 1999

January - August 2000

January - April 2001

May - June - July 2001

July - August 2001

Eruptive phases


1984 – 2001 effusion rate1984 – 2001 effusion rateEffusion rate

0

1

2

3

4

5

6

7

8

9

Time

Eff

usi

on

rat

e m

3/s

Dual band

Integr.Temp.

April - October 1984

March - July 1985

Dicember 1991 - March 1993

July - December 1997

March 1998

June - September 1998

Febrary - November 1999

January - August 2000

January - April 2001

May - June - July 2001

July - August 2001

Eruptive phases

Documents

Remote Sensing Laboratory ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA AVHoTRRA Valerio Lombardo GNV 2007 Progetto Etna