THE ASTER IMAGES FOR THE ENVIRONMENTAL MONITORING

Transcription

1 Dpartmento d Ingegnera per l Ambente e lo Svluppo Sostenble Facoltà d Ingegnera d Taranto POLITECNICO DI BARI THE ASTER IMAGES FOR THE ENVIRONMENTAL MONITORING M. G. Angeln, D. Costantno 4 WORKSHOP TEMATICO Dal Telerlevamento al Geo-Spatal Intellgence TARANTO - settembre

2 Am of Expermentaton montorng The ASTER mage es for the envronmental To evaluate the applcablty of the satellte ASTER (Advanced Spaceborne Thermal Emsson and Reflecton Radometer) mages n observaton, characterzaton and management of the terrtory Multtemporal Envronmental Montorng

3 ASTER satellte montorng The ASTER mage es for the envronmental ASTER s near-polar orbt Subsystem N. Band Spectral range (µm).5-. Spatal resoluton (m) Quantzaton level (bts).-.9 VNIR 5 N.-. SWIR TIR B Characterstcs of the three ASTER s sensor systems

4 Area of study The ASTER mages for the envronmental montorng

5 Dataset ASTER mages August 5 August 5 Multtemporal analyss The ASTER mages for the envronmental montorng

6 Preprocessng - Atmospherc correcton montorng The ASTER mage es for the envronmental Taranto mareograph staton SYNOP Brnds staton LIBR- Scheme of atmospherc correcton procedure n TIR range (CIRILLO) ( L,, τ ) L

7 ESN (Emssvty Spectrum Normalzaton) method montorng The ASTER mage es for the envronmental For a generc gray body (no black), the emssvty value n band s < : B ( T ) = ε L m, c 5 πλ e c λ T ( ε ) τ L + L = τ L + [ Wm µm sr ] The radance measured at the sensor can also be expressed as: τ, L and L were evaluated from atmospherc condtons. L, the radance atmosphercally corrected, s calculated as: L = L m, L τ L ( ε ) τ ε

8 LST by ESN montorng The ASTER mage es for the envronmental Usng a constant emssvty, for each channel: ε max.9 bare sol =.95 water surface ( ) c L m L L reversng and usng L, ε τ B max ( T ) = ε max : = c τ 5 λt πλ e T b, = c ε maxc λ ln 5 πl λ The emssvty spectrum: where Tˆ =,,N; N number of spectral bands + ( Tˆ ) ˆ ε = ε = { T b, },..., 5 = max = B L ( λ, Tˆ ) s the true temperature value, both two sample type Water and Sol.

9 Results ESN method montorng The ASTER mage es for the envronmental Colour Natural colour palette Tmax Water (K) 9 < Tmax Water < 9 9 < Tmax Water < < Tmax Water < < Tmax Water < Apparent temperature map, Tmax Water, for coverage Water // T 5 C Tmax Water ( C) < Tmax Water < 5 5 < Tmax Water < < Tmax Water < < Tmax Water < The thermal plume has average length of m from the pont of dscharge and present a T C that falls n prescrptons of normatve, the D.Lgs.5/ Norme n matera ambentale.

10 Results ESN method Apparent temperature map, Tmax Sol, for coverage Sol // The ASTER mages for the envronmental montorng

11 Results ESN method The ASTER mage es for the envronmental montorng Apparent temperature map, T max, for coverage Sol and Water // Apparent temperature map, T max, for coverage Sol wth two ranges of temperature hot water (coral) and cold water (blue), //

12 Results ESN method montorng The ASTER mage es for the envronmental Apparent temperature map, Tmax Water, for coverage Water 5//5 Apparent temperature map, Tmax Sol, for coverage Sol 5//5

13 Goodness of results obtaned n ESN method montorng The ASTER mage es for the envronmental Consderng the pxel at the same temperature, T true, and wth same emssvty, ε true, and the true extance of the pxel wll be E = ε B, true true ( λ T ) Wth the appled ESN method, aren t known prevously the temperature and emssvty values, therefore, was supposed a maxmum value of emssvty ε max that, n order to compute the estmate temperature value, T stm = B E λ, ε true max s entered n the nverse Planck s law. The error commtted s: = B true λ, B T = T stm T true ε true ( λ, T ) ε true max

14 montorng The ASTER mage es for the envronmental Goodness of results obtaned n ESN method a) coverage Water : ( ε =.95 max ) supposng an average true temperature value of b) coverage Sol : supposng: ε true ε true =.94 =.95 ε true ε true ( ε max =.9) = =.9 (desert envronmental) (vegetaton) T true 4 C T < K and T < K Compatble wth the absolute accuracy of the TIR subsystem: 4K [K] 4 K [K]

15 Expermental numercal model montorng The ASTER mage es for the envronmental Is based on the lnear nterpolaton prncple (least square nterpolaton): the problem s ndefnte of fve equatons n sx unknowns (5 emssvty values ε, =,,5 and a value of LST, T).. the temperature of sea and sol, consdered separately, n absence of thermal anomales, (for natural and/or anthropc actons) follow a lnear spatal varaton law;. n reference to spectral sgnatures, known and acqured from ASTER spectral lbrary, the most types of coverage analyzed have a trend of lnear type n the spectral range of the sensor TIR ASTER (.. µ m).

16 montorng The ASTER mage es for the envronmental Expermental numercal model Fundamental hypothess: assume that ε(λ) s smooth n the regon of three consecutve channels -,, +: ( ) ( ) ε λ + ε λ ε + ε ε ε ( λ ) = + + From (N per pxel) observatons, the avalable data are: ( ) ( ) L = ε τ B T + ε τ L + L k k k k The fnal equaton of the numercal method s: ε + ε + ε = ( ) C R L = ε B T L ε = (C columns and R lnes) C B ( T) L ( ) ( ) ( ) ( ) ( ) + ( ) ( ( ) ) ( ( ) ) + ( ( ) ) + ( ( ) ) F Tˆ ˆ ˆ ˆ ˆ ˆ ˆ = C D T D T + D T D T C D T D T C =

17 Smulaton montorng The ASTER mage es for the envronmental Smulated mage (9x9) contan classes of coverage of three macro categores, chosen from ASTER spectral lbrary: man made, sol and vegetaton % Re eflectance Constructon concrete 5 4,,5, 9 9, 9,5 9,,,4 wavelenght (mcrometer),5,9, Reflectance (%)

18 Structure of smulated mage The sample n fgure s repeated tmes n column and tmes n lnes, for a total of 9 lnes and 9 columns (94 pxels)

19 Smulaton montorng Choce of three ponts opportunely dstrbuted wth known coordnates: A = (,5) B = (,9) C = (,) The ASTER mage es for the envronmental Ponts wth known superfcal temperature value We suppose to known the superfcal temperature value: T A = 9. K (5. C) T B =. K (.4 C) T C =. K (. C)

20 At the nstant t =: T = a + c + b j montorng The ASTER mage es for the envronmental ( ) ( ) ( ) ( ) ( ) ( ) ( ) Resolvng: F Tˆ ˆ ˆ ˆ ˆ ˆ ˆ ( ) = C D T( ) D + T( ) + D T( ) D T( ) C+ D T( ) D + T( ) C = were calculated for TIR channels,, three T values: Total number of pxels n mage 94 T T T number of pxels (wth) 9 (5%) 44 (%) 94 (5%) Color Natural color palette Number of T value three T two T one T no one T Dstrbuton of pxel wth one, two, three or no one T value (=,,4)

21 Smulaton montorng The ASTER mage es for the envronmental Outlers dentfcaton and elmnaton from the elaboratons: Colour T T > 4K m Natural color palette Number of channel wth value T -T m <4 three two one no one Areal dstrbuton of pxel wth one, two, three or no one value T-Tm <4

22 Smulaton montorng The ASTER mage es for the envronmental For each pxel that had at least one temperature value for the three TIR channels (, and ) was dentfed the temperature value, calculated accordng to the crtera below: f one T value s avalable: T pxel =T f two T values are avalable: T pxel =( T + T j )/ f three T values are avalable: T pxel = (T + T + T )/. Estmate coeffcents, known T pxel regresson: Â A ˆ T T ˆ = B = ( ) Cˆ ε ε,, were obtaned appled a bdmensonal z A A A b Tˆ = Aˆ + Cˆ + Bˆ j ε ε ( Tˆ ) ( Tˆ ) mn max <. k =,...,5 ε k ( T ˆ ) = Rk Lk B ( Tˆ ) L k k

23 Smulaton of thermal anomales montorng The ASTER mage es for the envronmental We don t known the truth to the ground. Is not possble to dstngush the reason that gave the estmated temperature value of smooth type out from the realty. There are, n fact, two possble reasons:. the temperature values to the ground true n the specfc pont s very dfferent from the average value of the surroundng envronmental;. the pxel analyzed has a spectral sgnature to whch s not applcable the begnnng hypothess to the base of the model mplemented. The thermal anomales can be dentfed wth certan only for the classes of coverage wth spectral sgnature, and trend of tself, known

24 Smulaton of thermal anomales The ASTER mage es for the envronmental montorng The same mage was consdered n two dfferent epochs t and t, n whch were supposed know the two ntal temperature values, T and T : T = nstant t a + c + b j T = a + b + c j T = K nstant t wth n the regon ( : ) ( 55 : )

25 At nstant t was estmated Tˆ : The ASTER mage es for the envronmental montorng Color map of ntal temperature T at nstant t At nstant t was estmated : ˆT Color map of ntal temperature T at nstant t

26 Smulaton of thermal anomales montorng The ASTER mage es for the envronmental Explotng the prncple of multtemporalty of the known nformaton at the T ˆ Tˆ ( ) ( ) nstants t and t, was evaluated the dfference n absolute value ε ε (channel ) (channel ) (channel ) (channel ) (channel 4) ( Tˆ ) ˆ( ˆ ) ε T max ˆ ε <.9

27 Conclusons and Future perspectves montorng es for the envronmental The ASTER mage Conclusons. Good results. LST by ESN : T accuracy requrements on the TIR subsystem. Expermental numercal model. despte ts smplcty. gave good results, n smulaton, wht emssvty affect by errors < % Future perspectves.. To calbrate the expermental numercal model To fnd the possble correlatons between the dfferent coverage classes and the estmate emssvty values