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Soil Moisture Validation Activities

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					 Soil Moisture Validation
        Activities
       T. J. Jackson and M. Cosh
USDA ARS Hydrology and Remote Sensing Lab
                Sept. 2005
             Topics
•   Watershed validation networks
•   Temporal stability of Arizona
•   New sites
•   SMEX04
•   SMEX05
•   SMEX data sets and archive
•   Plans
ARS Watershed Soil Moisture
     Validation Sites

    Install
    Calibration
    Scaling (almost)
  • Access and Archive
                     AMSR-E Soil Moisture Validation

         AMSR-E U.S. Soil Moisture Validation Sites




                                                                                                                                                                                Little River, GA
Reynolds Creek, ID

                                                                                         + Rain gage                                                   + Rain gage
                                                    35.05                               + Existing SM site     31.80                                   + Existing SM Site



                                                    34.95                                                      31.70




                                                    34.85                                                      31.60




                                                    34.75                                                      31.50
                             Latitude N (Degrees)




                                                            a) Little Washita, OK                                      b) Little River, GA
                                                    34.65                                                      31.40
                                                       -98.30      -98.20      -98.10   -98.00     -97.90         -83.90      -83.80         -83.70     -83.60       -83.50




                                                                                         + Rain gage                                                   + Rain gage
                                                    31.90                               + Existing SM Site     43.35                                   + Existing SM Site



                                                    31.80                                                      43.25



     Walnut Gulch, AZ
                                                    31.70
                                                                                                                                                                               Little Washita, OK
                                                                                                               43.15




                                                    31.60                                                      43.05




                                                            c) Walnut Gulch, AZ                                        d) Reynolds Creek, ID
                                                    31.50                                                      42.95
                                                      -110.25     -110.15     -110.05   -109.95    -109.85       -117.00      -116.90        -116.80    -116.70      -116.60



                                                                                                       Longitude W (Degrees)
 Description and Status of Watershed
              Networks
Watershed               Type           # Sensors       Reporting
Walnut Gulch, AZ      Semi-Arid           21            20 min
Reynolds Creek, ID    Mountainous         16            1 hour
Little River, GA      Forest              19            30 min
Little Washita, OK    Grazingland         19            30 min


            *All watersheds currently downloading daily.
                         RG400


        Walnut Gulch, AZ Soil Moisture Network
                    and Raingages
                                                                                                             RG69

                                                                                                             RG70
                                                                                               RG89

                                                                               RG87
                                                       Lucky Hills      RG71

                        RG92
                                                                                                      RG82

                                                                                           RG57
                                     RG13                                       RG40
5 cm              RG03     RG76
                                                                     RG28



       3-7 cm                            RG18
                                                                                        RG46

                                                                     RG34
                                  RG14


                                                                               RG37

                                                RG20

                                                                                RG100


                                                 Raingage
       RG600                                     Flume
                                                 Vitel Soil Moisture
   25 by 15 km domain                            Profile Soil Moisture
                                                 Surface Flux

   81 Raingages – 19 Vitel sites (21 Total): continuous, every 20 min., long term
               RG400


 Walnut Gulch, AZ Soil Moisture Network
             and Raingages
                                                                                                          RG69
                SMEX04                                                                                    RG70
                                                                                     RG89

                                                                     RG87
                                             Lucky Hills      RG71

           RG92
                                                                                               RG82

                                                                                 RG57
                           RG13                                       RG40
        RG03                                               RG28
                 RG76


                                                                              RG46
                               RG18
                                                           RG34
                        RG14


                                                                     RG37

                                      RG20

                                                                      RG100


                                       Raingage                                       81 Raingages
RG600                                  Flume                                          69 Sampled during SMEX04
                                       Vitel Soil Moisture                            11:30am-2:30pm
                                       Profile Soil Moisture
                                       Surface Flux                                   25 by 15 km domain

                  Daily sampling during SMEX04 =                                        +
                                                Walnut Gulch Time Series of Soil Moisture
                                                     February to September, 2004

                                    0.35
                                                                         Vitel_Average
                                                                         SMEX04_GVSM
                                     0.3
Volumetric Soil Moisture, m 3/m 3




                                    0.25


                                     0.2


                                    0.15


                                     0.1


                                    0.05


                                      0
                                           38   88   138           188       238
                                                       Day, 2004




   SMEX04 comparison of 19 automated in situ sensors (solid-line time-series) and 69
   sites sampled using a gravimetric method (red symbols). The example demonstrates
   that reliable area average soil moisture can be obtained using the automated sensors.
  Plans for Data access and Archival
• Web page interface with monthly files available.
• Scheduled Beta-testing   October 15, 2005
• Full release             November 30, 2005

Web-Address:
http://hydrolab.arsusda.gov/ARS_Soil_Moisture/
     Insitu Soil Moisture Supporting
      Modeling and Remote Sensing

•   Take advantage of existing infrastructure
•   Strive for consistency and standardization
•   Link long term points to short term spatial
•   Exploit temporal stability
•   Consistent measurements
•   Expand what we can (Sonora, Salamanca,..)
•   5 cm!
Sonora, MX Soil Moisture and Precipitation Network (50 x 85 km)
                 University of Sonora, Mexico




 Landsat false color image
     August 30, 2004




   Network has been operating since June 2004 measuring soil moisture at a depth of 5 cm for
   14-locations using Vitel probes. Each site has a raingage and two site have additional soil
   moisture depths. Data are recorded every 20 minutes to data loggers.
  REMEDHUS* Soil Moisture Stations Network (33 x 38 km)
          University of Salamanca, Spain
REMEDHUS




                                                                                    Tektronix 1502C




                                                                        cm
                                                                          0


                                                                         10



                                                                         20



                                                                         30



                                                                         40



                                                                        50




Network (23 sites) has been operating since June 1999 measuring soil moisture at depths of
5, 25, 50 and 100 cm at 14-days intervals using TDR probes. Vitel probes were added for 5
cm data every 20 min.
*Red de Estaciones de Medición de la Humedad del Suelo
     SMEX Science Objectives
• Validation of Aqua AMSR-E TB and soil moisture
  products for a range of land cover types
• Development and verification of soil moisture
  retrieval algorithms for a range of biomass levels
  for current (C) Band) and future (L Band) passive
  microwave missions and Envisat ASAR
• Soil moisture sampling-scaling, calibration and
  method, establishing insitu networks
• Demonstration of new soil moisture retrieval
  concepts and technologies (GPS, PALS, 2DSTAR)
• Robust data sets for follow-on modeling including
  land atmosphere interactions
  SMEX: A Series of Intensive Field
Campaigns Incorporating Diverse Land
       Covers and Climates

   United States        SMEX02 and SMEX05: IA



                    SMEX03: OK
                                 SMEX03: AL

      SMEX04: AZ                  SMEX03: GA


       SMEX04: MX
              SMEX04 Elements
• Two regional study sites, Arizona and Sonora provide
  diverse vegetation and topographic variations
• Insitu networks in each region provide long term soil
  moisture
• Field campaign August 2-August 27, 2004 with intensive
  ground sampling concurrent with aircraft and Aqua
  AMSR-E
• Aircraft mapping
• Satellite retrievals
Landsat TM Coverage of the SMEX04 Region in 2004




    June 11, 2004               July 29, 2004 SMEX04 August 30, 2004
    These are false color composites of two images. Study areas are outlined
              SMEX04 Elements
• Two regional study sites, Arizona and Sonora provide
  diverse vegetation and topographic variations
• Insitu networks in each region provide long term soil
  moisture
• Field campaign August 2-August 27, 2004 with intensive
  ground sampling concurrent with aircraft and Aqua
  AMSR-E
• Aircraft mapping
• Satellite retrievals
         SMEX04                                          AZ01
                                                                                 AZ17



   AZ Intensive Sampling                                        AZ02
                                                                                                            AZ19

                                                                                          AZ18
                                          AZ03

                                                                                                            AZ20
        Regional Sampling                                                                      C
                                         AZ04    A
                                                                                 AZ23           AZ22
         40 sites sampled daily                 AZ06     AZ07
                                  AZ05
         11:30am-2:30pm                                                                       AZ26
                                                                                                                   AZ21

         50 by 75 km domain         AZ08                                           AZ25



                                                                                                     AZ27

                                                                AZ24
         Watershed Sampling                      AZ09/WG400
                                                                                   D
                                                                                  AZ29/WG68
                                           AZ10/WG92             AZ30/WG44
                                                                                                        AZ28
                                                        AZ11/WG13

                                                                     AZ31/WG34
                                  AZ14

                                                                                  AZ40
                                     AZ12

65 sites sampled daily                                                                          AZ39        AZ38
                                                                 AZ32
11:30am-2:30pm                     AZ13

25 by 15 km domain
                                         B                    AZ33
                                                                                          E                    AZ37
                                                                         AZ34



             Ease-Grid              AZ15               AZ16
                                                                                   AZ35          AZ36
              SMEX04 Elements
• Two regional study sites, Arizona and Sonora provide
  diverse vegetation and topographic variations
• Insitu networks in each region provide long term soil
  moisture
• Field campaign August 2-August 27, 2004 with intensive
  ground sampling concurrent with aircraft and Aqua
  AMSR-E
• Aircraft mapping
• Satellite retrievals
  SMEX04 PSR/CX and AMSR-E/WindSat Coverage
         Aircraft Mission        Satellites        Antecedent Precipitation
August   AZ            SO   AMSR-E       WindSat      AZ            SO
  5      X              X     X             X         X              T
  6                                                    T             X
  7                   X        X
  8      X            X                                X             X
  9      X            X        X           X                         X
  10     X            X        X           X           X             T
  11                                       X
  12     X            X        X                       T             X
  13     X            X                                              T
  14                  X        X           X           X             X
  15                                       X           X             X
  16                           X           X           X             X
  17                                                                 X
  18                           X                                     X
  19                           X                       T             T
  20                                       X
  21                           X           X
  22                                       X
  23                           X
  24     X            X
  25     X            X        X                       X             X
  26     X            X        X           X
   PSR Data Sets and Processing
• 84 high altitude flightlines resulting in 21
  mapping domains (10 – AZ and 11 - SO)
• RFI analysis: best channels 7.32 GHz and
  10.7 GHz
• RFI removal
• Temporal normalization of multiple
  flightlines
• 800 m grid mapping (high altitude nominal
  beam position spacing is 300 m)
                                     SMEX04 PSR 7.32H (Arizona)
              08/05/04                08/08/04                      08/09/04                            08/10/04                    08/12/04


3540000



3520000



3500000



3480000


              08/13/04                                              08/24/04                            08/25/04                    08/26/04


3540000



3520000



3500000



3480000
          580000   600000   620000                                                                580000      600000   620000   580000   600000   620000
                                                              580000      600000   620000

                                                  Brightness Temperature (K)
                                      200

                                            210




                                                              240

                                                                    250




                                                                                            280
                                                  220

                                                        230




                                                                             260

                                                                                   270




                                                                                                  290

                                                                                                        300
                  Arizona Landsat 5 (July 29)                                             Arizona PSR (August 24)
                                                                                                 C Band H
                    Dry lake bed that flooded                                            Dry lake bed that flooded

Areas wetted by rainfall cells                                  Areas wetted by rainfall cells




                                  Mountain                                                                 Mountain




                                 Different surface conditions                                             Different surface conditions


                                                                                                          W                         E

                            Mountain                                                                Mountain




                                                                                                  Brightness Temperature (K)
                                                                             200




                                                                                                    230

                                                                                                           240




                                                                                                                             270

                                                                                                                                   280
                                                                                   210

                                                                                            220




                                                                                                                 250

                                                                                                                       260




                                                                                                                                         290

                                                                                                                                               300
West

       Different surface conditions




                  East
                      Potential Effects of Surface Rocks on
                   Microwave Remote Sensing of Soil Moisture
             1.0
                                                                     •   Rocks occupy volume but do
             0.9
                                                                         not hold water: the range of
             0.8                                                         possible soil moisture as well
Emissivity




                                        60%   35%     20%       0%
             0.7                                                         as that of TB will decrease as
                                                Rock Fraction

             0.6
                                                                         RF increases
             0.5
                                                                     •   Surface rocks contribute to
                   0      5        10         15       20
                              Volumetric Soil Moisture (%)
                                                                25
                                                                         roughness
             •         Thermal features of rocks will be different than soils
             •         All of these factors will contribute to generally high TB
                       (emissivity) that shows little variability (roughness and
                       temperature may have a frequency component)
      Brightness Temperature Comparisons
                       Arizona (AZ) Domain



• 10.7 GHz                                320

  PSR~AMSR
                                          310
  (H&V)
• V>H (typical low      AMSR TB (K) (K)
                                          300

  vegetation result)
                                          290
• 6.9 GHz
                                          280
  AMSR>PSR                                                                           6.9 V
                                                                                     6.9 H
  (H&V)                                   270                                        10.7 V
• Problem: RFI                                                                       10.7 H
                                          260
• PSR observed                                  260   270   280      290       300   310      320
  earlier in day                                                  PSR TB (K)
     Brightness Temperature Comparisons
                      Sonora (SO) Domain


• 10.7 GHz                         320
  PSR~AMSR
                                   310
  (H&V)
• 6.9 GHz                          300

                       AM TB (K)
  PSR~AMSR               SR        290
  (H&V)
• V~H (typical of                  280                                  6.9 V
                                                                        6.9 H
  increasing                       270                                  10.7 V
  vegetation)                                                           10.7 H
                                   260
• Limited range for                   260   270   280     290     300   310      320
  AMSR-E TB                                              SR B )
                                                        P T (K
             Unresolved issues

• Topography: incidence angle
• Rocks: dielectric properties, interpretation of
  VSM, surface roughness
• Observation time: PSR observations were
  made earlier in the morning than AMSR-E
• Spatial scale: dynamic range of AMSR
  observations is much smaller than PSR
  observations
                    Summary
• PSR is a proven airborne radiometer system which has
  performed well during a number of SMEX experiments
  (SGP99, SMEX02, SMEX03, SMEX04)
• There is RFI contamination over the AZ domain for C-
  band observations. C-band observations over SO and
  for X-band do not exhibit obvious RFI effects
• Spatial patterns of PSR observations over AZ and SO
  are consistent to geophysical features and weather
  events
• Rock fraction may reduce the utility of high frequency
  channels in soil moisture retrieval, even if it is
  essentially bare soil
• Work continues on topography and soil moisture
  products
         SMEX05 Objectives
• Controlled condition data to understand
  polarimetric signatures of structured vegetation,
  tillage, and soil moisture at CMIS frequencies
• Define the effects of dew on microwave emission
  and explore techniques for the screening and/or
  correction (*Hydros relevance)
• Forest sites observations
• Evaluation and testing of RFI suppression
  techniques
• Follow on AMSR-E validation
NRL WindSat Radiometer
       WindSat is the first spaceborne
       Polarimetric Microwave Radiometer
    Frequency
                 SSM/I     AMSR-E    WindSat      CMIS      SMOS       Hydros
      (GHz)
       85/91      V, H      V, H         -         TBD         -           -
         37       V, H      V, H     V, H, U, F    TBD          -          -
       22/23      V, H      V, H        V, H       TBD          -          -
         19       V, H      V, H     V, H, U, F    TBD          -          -
        10.8       -        V, H     V, H, U, F    TBD          -          -
        6.8        -        V, H        V, H       TBD          -          -
        1.4        -         -           -          -         V, H      V, H, U
    37 IFOV,                                                *50@1.4   *10-40@1.4
                 27x38      8x14       8x13        TBD
        km                                                    Ghz        GHz
    Observing
                 Various   1:30 pm    6:00 am     6:00 am   6:00 am    6:00 am
       Time
     Period of
                  1985-     2002-      2003-       2009-     2007-      2010-
      Record
      NRL Airborne Polarimetric Microwave
     Imaging Radiometer (APMIR) in SMEX05
•   Fully polarimetric channels
•   Only C and X available
•   Can mimic space-borne sensor conical scan
•   Fixed beam selected to provide fixed
    target/sensor geometry
•   Scan in elevation angle (0 to 60 degrees) and
    spin in azimuth (0 to 360 degrees)
•   Spatial resolution selected to provide
    adequate within field sampling

           APMIR Frequencies and Coverage (based on a 53 degree incidence angle)
                                         Altitude = 7.6 km      Altitude = 0.9 km
                          Beam width Footprint        Swath         Footprint
          Channel (GHz)      (Deg)       (km)          (km)            (km)
            6.6, 6.8, 7.2     9.4      2.1 x 3.5        20          0.24 x 0.42
                10.7          5.9      1.3 x 2.2        20          0.15 x 0.27
           18.7 / 19.35       6.8      1.5 x 2.5        20          0.18 x 0.30
           22.235 / 23.8      5.3      1.2 x 1.9        20          0.15 x 0.24
                 37            6       1.3 x 2.2        20          0.15 x 0.27
SMEX05/POLEX Summary of Aircraft and Satellite Coverage
 (Daytime Passes of W=Windsat, A=AMSR, L5=Landsat 5)
       June 12      13       14          15       16           17       18
                    W        W           W
       A                     A           A                     A
                                         L5       P3 Transit
                                                               Flight   Flight
                             Briefings
       19           20       21          22       23           24       25
       W            W        W                                          W
       A                     A                                 A
                             ASAR        L5                    ASAR
       Flight       Flight   Flight      Flight

       26           27       28          29       30           July 1   2
       W                                          W            W        W
       A                     A                    A            A
                                                               L5
       Flight       Flight                        Flight       Flight   Flight

       3            4        5           6        7            8        9
                                         W        W            W
       A                     A                    A
       P3 Transit   ASAR                                       L5
                          Walnut Creek Watershed Vegetation Conditions
  Vegetation Water Content from SMEX02
                           June 16               July 2
                6


                5
                                                                     Corn mid June       Corn late June
 VWC in kg/m2




                4


                3
                                                          Corn
                                                          Soybean
                2


                1


                0
                    160      170           180            190
                                     Day of Year

Red indicates expected SMEX05 study period



                                Forest                              Soybeans mid June   Soybeans late June
                 June 6, 2005
SMEX05
Landsat 5 TM
Images of the
Walnut Creek
Watershed Area
                 June 22, 2005




                 July 1, 2005
                        Group            Data Set             SMEX02   SMEX03                     SMEX04        SMEX05
                                                                IA       GA     AL   OS/ON   BZ     AZ     SO     IA
                        Aircraft         PSR                                                 --
                                         ESTAR/2DSTAR                                        --                   --
    SMEX DATA                            GPS                                                 --     --     --
                                         AIRSAR                          --     --           --     --     --     --
       SETS             Ancillary
                                         AVIRIS
                                         Land Cover
                                                                --       --     --    --     --                   --


     (08/15/05)                          Geolocation
                                         Soils
                                         Photographs
                                         Surface Roughness
•   SMEX02-complete     Soil Moisture    Regional                                                                 --
                                         Watershed/Transect              --     --           --
•   SMEX03-loose ends                    Vitel Network
                                         SCAN                                                --            --

•   SMEX04-June 2006    Meteorological   Sunphotometer
                                         Precipitation
                                                                         --     --           --            --

                                         Apogee Network                  --     --           --     --            --
•   SMEX05-TBD                           Mesonet                --       --     --           --     --     --     --
                                         ARM                    --       --     --           --     --     --     --
                                         SCAN                                                --            --
                                         Flux Measurements               --     --    --     --
                        Satellite        AMSR
                                         WINDSat                --
                                         ASAR Imagery           --                           --
                                         ASTER                           --     --
                                         AVHRR                  --                           --
                                         GOES                                                --
                                         NDVI/NDWI                                           --
                                         Quickscat
                                         SSM/I
                                         TERRA-MODIS                     --     --    --     --
                                         TM Imagery
                                         TMI                    --                                                --
                        Vegetation       Regional                                                                 --
                                         Watershed/Transect              --     --           --     --     --
                                         MSR/LAI                --       --     --           --            --
                                         VWC Maps                                            --
                  Plans
•   Idaho watershed data
•   Watershed archive
•   New sites?
•   SMEX03 archive (ASAP)
•   SMEX04 special issue of RSE
•   SMEX04 archive (June 2006)
•   SMEX05 processing

				
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Description: Soil Moisture Validation Activities