Research on Soil Moisture and Evapotranspiration using Remote Sensing

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1 Research on Soil Moisture and Evapotranspiration using Remote Sensing Prof. dr. hab Katarzyna Dabrowska Zielinska Remote Sensing Center Institute of Geodesy and Cartography Warszawa Jasna 2/4

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3 Field Measurements at the Middle Biebrza Basin May, June, July, August 2000 May, June, July 2001 May, June, July 2002 Satellite Images: Landsat TM - May 2000 SPOT/VEGETATION May 2000; May 2001 ERS/ATSR May 2000; May 2001 ERS. SAR May, June, July, August NOAA/AVHRR ERS-SAR 1995, 1997, 2000, 2001, ENVISAT TERRA MODIS; ASTER

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5 Field data Satellite data optical and microwave Land Use Digital Terrain Model Soil Map Meteorological Data Evapotranspiration soil moisture Modelling Water Balance

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7 Satellite Data OPTICAL DATA MICROWAVE DATA Classification of vegetation LAI EVAPOTRANSPIRATION Soil Moisture

8 ERS-2. PRI The impact of ground truth variables on microwave signals expressed by backscatter coefficient has been examined Mirror reflection Smooth surface Smoothed area reflects radiation as mirror surface, what causes minimal return to the receiver. Such objects are dark. Mixed reflection Scattered reflection Rough area reflects radiation in different angles what causes that most of the radiation returns to the receiver. Such surfaces are light

9 The registered microwave signal depends on: Configuration of the system (stable): frequency (length) of generated wave, polarisation ( VV, HH; cross - HV, VH), angle of radiation between perpendicular and the surface Surface properties (variable): Surface roughness

10 ERS-2.SAR Image

11 Backscattering coefficient Soil moisture for grassland classes wody, chmura [db] km wody, chmura [% obj.] ERS-2.SAR ERS-2.SAR WG = f (grassland class, LAI, )

12 Backscattering coefficient Backscattering coefficient Backscattering coefficient Backscattering coefficient

13 Soil Moisture in the classified grassland areas Based on

14 Soil Moisture in the classified grassland areas

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16 Opady (mm) suma opadów (mm) stycze luty marzec kw iecie maj czerw iec lipiec sierpie w rzesie miesic/dekada

17 OPTICAL DATA Satellite/ Radiometer/ Landsat ETM Spectral resolution Wavelength µm Blue Green Red NIR SWIR SWIR Radiative temperatur e 8-14 µm SPOT/VEGETA TION-Spectral resolution ERS2/ATSR µm NOAA/AVHRR µm

18 LE = RN H - G RN = LE +H+ G where: RN - the rate of net gain of heat from radiation (measured) (Wm - ²) LE - the rate of loss of latent heat by evapotranspiration (Wm - ²) H - the rate of sensible heat loss by convection (Wm - ²) G - the rate of heat loss into the ground (measured) (Wm - ²) The values of the rate of sensible heat loss by convection (H) has been calculated as follows: H = (pc p (T S -T a ))/r a p - air density (kgm - ³) C p - specific heat of air (Jkg -1 K -1 ) T s - surface temperature from ATSR corrected due to atmospheric water vapour T a - air temperature measured at the study area ( C) r a - air resistance for heat transfer (sm -1 ) The values of air resistance (r a ) have been calculated as follows:

19 Surface Temperature

20 Latent Heat flux

21 LE [W/m2] GRASS MEADOWS, 2-PASTURES AND MEADOWS WITH SEDGE, 3-SEDGE-CANARY-GRASS MEADOWS, 4-GRASS AND HERBACEOUS MEADOWS, 5-SEDGE-GRASS MEADOWS, 6- MARCH SEDGE MEADOWS LE i = RN i E D RN D LE i E D = RNi RN D

22 Daily Evapotranspiration

23 Daily Evapotranspiration

24 σ 0 = σ v0 + τ 2 σ s 0 Grassland classes LAI (GEMI, NDVI...) Soil moisture Vegetation impact expressed by indices Soil moisture using new derived index IW = σ a σ w σ s σ s

25 Changes in humidity on in relation to (based on ERS2-SAR data)

26 Changes in humidity on in relation to (based on ERS2-SAR data)

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28 Average backscattering coefficient in each land use class calculated from ERS-2. SAR

29 NDVI index from Landsat ETM NDVI index from Landsat ETM

30 Opady (mm) suma opadów (mm) stycze luty marzec kw iecie maj czerw iec lipiec sierpie w rzesie miesic/dekada

31 Backscattering coefficient from ERS.2 SAR

32 NDVI for grassland classes using ERS2.SAR

33 Average values of NDVI for grassland classes using Landsat ETM

34 Average values of backscattering coefficient for grassland classes using ERS2.SAR

35 Flooded Areas

36 ENVISAT ASAR OSOWIEC OSOWIEC WIZNA WIZNA

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39 MERIS IMAGE from

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