Workshop on climatic analysis and mapping for agriculture 15 June 2005

Frost mapping with NOAA- AVHRR data

G. Antolini, V. Marletto

ISTITUTO DI BIOMETEOROLOGIA CONSIGLIO NAZIONALE DELLE RICERCHE

Meteorological Service – Enviromental Protection and Prevention Agency

Remote Sensing Laboratory

With the collaboration of:

M. Menenti, Z.L. Li, F. BeckerLaboratoire des Sciences de l'Image, de

l'Informatique et de la Télédétection Université Louis PasteurStrasbourg

Workshop on climatic analysis and mapping for agriculture 15 June 2005

What we needed…

We need to assess the spatial variability of frost, in order to:

- Validate our interpolation models and improve them- Realize a frost risk map for Emilia-Romagna- Assess the simulation of frost events with numerical meteorological models

By frost maps we mean night Land Surface Temperature (LST) maps, during a frost event

Workshop on climatic analysis and mapping for agriculture 15 June 2005

What is frost…

Physical meaning: a phase change in water (from liquid or vapor to solid)

We want to know where frost is more likely to occur in order to plan crop protection (radiative frost).

Agrometeorological meaning: low temperatures that causes ice formation in crop cells

Workshop on climatic analysis and mapping for agriculture 15 June 2005

What is frost…

Typical synoptic situation

Typical micrometeorological conditions

Workshop on climatic analysis and mapping for agriculture 15 June 2005

833 km, 7:30 a.m. descending node (NOAA12) ; 13:30 p.m. ascending node (NOAA14), sun-synchronous, near-polar, circular

Orbit:

± 55°± 55°± 55°± 55°± 55°FOV

1.11.11.11.11.1Spatial resolution km

2399

0.12 K

1.41

Insb

33.55-3.93

2399

0.12 K

1.41

HgCdTe

410.3-11.3

239923992399Swath km

0.12 KS/N > 3:1S/N > 3:1Radiometric precision

1.391.511.39 I FOV mrad

HgCdTeSiSiDetector

511.4-12.4

20.725-1.00

10.58- 0.68

Spectral bands (µm)

833 km, 7:30 a.m. descending node (NOAA12) ; 13:30 p.m. ascending node (NOAA14), sun-synchronous, near-polar, circular

Orbit:

± 55°± 55°± 55°± 55°± 55°FOV

1.11.11.11.11.1Spatial resolution km

2399

0.12 K

1.41

Insb

33.55-3.93

2399

0.12 K

1.41

HgCdTe

410.3-11.3

239923992399Swath km

0.12 KS/N > 3:1S/N > 3:1Radiometric precision

1.391.511.39 I FOV mrad

HgCdTeSiSiDetector

511.4-12.4

20.725-1.00

10.58- 0.68

Spectral bands (µm)

What we used…

NOAA Polar orbiter satellite

AVHRR sensor

Workshop on climatic analysis and mapping for agriculture 15 June 2005

What we used…

Workshop on climatic analysis and mapping for agriculture 15 June 2005

1exp 25

10

TC

CTB

Planck blackbody law:

A few words on theory…

Problems:

Land surface is not a perfect blackbody.

The emitted radiance depends on spectral emissivity and land surface temperature.We cannot assume homogenous emissivity.There are always one more missing variable than equations (N channel emissivities + surface temperature).

Atmospheric correction

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Processing of NOAA-AVHRR data

Pre-processing of raw data

- Calibration- Navigation (manual or automatic)

Processing of calibrated data

- Cloud detection and masking- Atmospheric correction- Surface emissivity retrieval- Land surface temperature retrieval

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Pre-processing…

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Cloud detection

Saunder and Kriebel (1988, IJRS, 9: 123-150)Gesell (1989, IJRS,10: 897-905) for ice/snow detection

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Atmospheric correction

Atmospheric water vapor retrieval

Ch. 4 Ch. 5

MODTRANRadiosoundsRadiative transfer modelling to compute unknown atmospheric radiative quantities

Computation of night and day surface brightness temperature

Atmospheric quantities

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Surface emissivity retrieval

TISI (Temperature-Independent Spectral Indices)

Day surface brightness temperature

Ch. 3, 4, 5

March 17th 2003, 04:25 UTC

Night surface brightness temperature

Ch. 4, 5

March 19th 2003, 15:01 UTC

Emissivity depends on:

Composition of surface

Roughness of surface

Other physical parameters (soil moisture…)

Wavelength

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Land surface temperature retrieval

Surface emissivityAtmospheric quantities maps (atmospheric correction results)

Split window algorythm

Workshop on climatic analysis and mapping for agriculture 15 June 2005

March 17th 2003 04:25 UTC

Workshop on climatic analysis and mapping for agriculture 15 June 2005

March 23th 2003 03:39 UTC

Workshop on climatic analysis and mapping for agriculture 15 June 2005

April 9th 1997 02:04 UTC

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Comparison with observations(spatial interpolation methods)

Some considerations:

- thermodynamique vs radiometric temperatures- time lag- spatial resolution- surface vs air temperature

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Frost risk mapping

LATE FROST RISK

low medium high very high

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Numerical weather simulations

RAMS (Regional Atmospheric Modeling System)

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Thanks for your attention

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Satellite

Atmosphere

Outer of atmosphere

Sun

Surface

A few words on theory…

Workshop on climatic analysis and mapping for agriculture 15 June 2005

T

B

RRTTTT

i

ati

i

iai

i

iiS

i

)(1)(

1

Effects on LST of atmosphere (transmissivity) and emissivity

i

0,89 0,90 0,91 0,92 0,93 0,94 0,95 0,96 0,97 0,98 0,99 1,00

Ts-

Tgi

0

1

2

3

4

5

6

TropicalMidlatitude summerMidlatitude winter

Channel 4

different slopes correspond to different Ts (20 °C variation) for same atmosphere

Tgi

250 255 260 265 270 275 280 285 290 295 300 305 310 315 320

Tg

i-Ti

-2

-1

0

1

2

3

4

5

6

7

8

9

10

11

12

TropicalMidlatitude summerMidlatitude winter

Channel 4

Workshop on climatic analysis and mapping for agriculture 15 June 2005

Becker F., Li Z. L., 1995. Surface temperature and emissivity at various scales: definition, measurement and related problems. Remote Sensing Reviews, vol. 12, 225-253.

Gesell, G., 1989. An Algorithm for Snow and Ice Detection Using AVHRR Data: An Extension to the APOLLO Software Package. Int. J. Remote Sensing 10, 897-905.

Li Z.L., Becker F., Stoll M.P., Wan Z., 1999. Evaluation of six methods for extracting relative emissivity spectra from thermal infrared images. Remote Sens. Environ. 69, 197-214.

Nerry F., Petitcolin F., Stoll M.P., 1998. Bidirectional reflectivity in AVHRR channel 3: application to a region in Northern Africa. Remote Sens. Environ. 66, 298-316.

Saunders R.W., 1986. An Automated Scheme for the Removal of Cloud Contamination from AVHRR Radiances over Western Europe. Int. J. Remote Sensing 7, 867-886.

Saunders, R.W., Kriebel, K.T., 1988. An Improved Method of Detecting Clear Sky and Cloudy Radiances from AVHRR Data. International Journal of Remote Sensing 9: 123-150.

Sobrino J.A. (ed.), 2000. Teledetección. Servicio de Publicaciones, Universidad de Valencia, ISBN 84-370-4220-8, 467 pp.

Sobrino J.A., Raissouni N., Li Z.L., 2001. A comparative study of land surface emissivity retrieval from NOAA data. Remote Sens. Environ. 75, 256-266.

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