2005 ARM Science Team Meeting, March 14-18, Daytona Beach, Florida

Canada Centre for Remote Sensing - Centre canadien de télédétection Geomatics Canada Natural Resources Canada - Géomatique Canada Ressources Naturelles CanadaContact Information: Alex Trishchenko, Tel (613) 995-5787, Email trichtch@ccrs.NRCan.gc.ca

Spectral, temporal and spatial properties of surface BRDF/albedo over the ARM SGP area from multi-satellite observationsSpectral, temporal and spatial properties of surface BRDF/albedo over the ARM SGP area from multi-satellite observations

IntroductionSurface albedo serves as an important input for atmospheric radiation and climate modeling and analysis. The characterization of spectral, temporal and spatial properties of surface bi-directional reflectance (BRDF) and albedo was the major objective of our project. In the poster we will summarize our efforts to characterize surface BRDF and albedo properties over the ARM Southern Great Plaines (SGP) region of 30-40°N, 92-102°W from multiple satellite missions: MODIS on Terra and Aqua, VGT, AVHRR, Landsat and ASTER, as well as from ground observations. Our approach was to generate 10-day BRDF/albedo maps with resolution 500m from MODIS and 10-days, 1-km resolution maps from VGT, AVHRR from 1995 to 2004. The landcover-based fitting approach is implemented to derive BRDF/albedo parameters. We will present analysis of multiyear datasets and discuss spectral, temporal and spatial variability of surface albedo over the ARM SGP area. The consistency and discrepancy between different satellite datasets will be considered. 4 field campaigns (Intensive Operational Periods -IOP) have been conducted to gather landcover and surface albedo information of various seasons and for validation purpose. Multi-angular sensor data (MISR) and high spatial resolution imagery (LANDSAT and ASTER) and some aircraft observations have been also used to validate satellite-derived products.

VEGETATION/SPOT4

MODIS

36N

38N

34N

96W 94W98W100W

Trishchenko, AlexanderTrishchenko, Alexanderaa, Luo, Yi, Luo, Yibb, Li, Zhanqing, Li, Zhanqingcc, Park, William , Park, William aa, and Khlopenkov, Konstantin, and Khlopenkov, Konstantinaa

a a Canada Centre for Remote Sensing, Canada Centre for Remote Sensing, b b Noetix Research Inc., Canada, Noetix Research Inc., Canada, c c University of MarylandUniversity of Maryland

Available satellite/sensors and time spanPlatform/SensorPlatform/Sensor Time SpanTime Span

Surface Surface ResolutionResolution

Spectral Band (Spectral Band (m)m)

Terra/MODISTerra/MODIS 2000.03-2004.102000.03-2004.10 500m500m 0.4, 0.5, 0.6, 0.8, 1.2, 1.6, 2.10.4, 0.5, 0.6, 0.8, 1.2, 1.6, 2.1

Aqua/MODISAqua/MODIS 2003.03-2004.102003.03-2004.10 500m500m 0.4, 0.5, 0.6, 0.8, 1.2, 1.6, 2.10.4, 0.5, 0.6, 0.8, 1.2, 1.6, 2.1

SPOT/VGTSPOT/VGT 1998.04-2004.101998.04-2004.10 1.0km1.0km 0.4, 0.6, 0.8, 1.60.4, 0.6, 0.8, 1.6

NOAA/AVHRRNOAA/AVHRR 1995.01-2000.101995.01-2000.10 1.0km1.0km 0.6, 0.85, 3.70.6, 0.85, 3.7

LandsatLandsat Selected datesSelected dates 30m30m 0.4, 0.5, 0.6, 0.8, 1.6, 2.2 0.4, 0.5, 0.6, 0.8, 1.6, 2.2

AsterAster Selected datesSelected dates 15m, 30m15m, 30m 14 bands VIS, SWIR, TIR14 bands VIS, SWIR, TIR

Surface albedo (NIR) of May through 1995 to 2004

199

519

96

199

719

98

199

920

00

200

120

02

200

320

04

Comparison of albedo between VGT and MODIS

Validation of albedo with ground measurements

5/11/2003Wheat field 5/11/2003 5/12/2003Grassland Young corn field

Validation of albedo with MISR observations

Landcover type around ARM-SGP CF during three IOPs derived from Landsat and ASTER images and ground survey

Landcover types aroundARM-SGP CF, Sep 2002

Spectral response function of different sensorsSpectral correction of Landsat

bands to MODIS bands

Landsat-7 Surface Reflectance 30-m Pixel

Landsat-7 Surface Reflectance500-m Aggregation

MODIS Surface Reflectance 500-m Pixel

Landsat-7 vs MODIS Surface Reflectance Summary

Surface BRDF/albedo products over the ARM SGP area 30-40°N, 92-102°W have been generated from multiple satellite missions: MODIS on Terra and Aqua, VGT, AVHRR from 1995 to 2004. Spatial resolution is 500m for MODIS and 1km for other sensors. Temporal resolution is10-day interval (3 per month).

The landcover based BRDF fitting (LBF) approach has been developed. Method can be easily applied for joint data processing from multiple platforms. Spectral correction procedure has to be implemented to merge data from similar but not identical sensors to account for spectral response function effect.

BRDF/albedo results were compared with ground measurements and observations from other sensors. The primary results show good agreements. Some additional validation efforts are required to reduce variability between different missions.

Generated BRDF/albedo data have been released through the CCRS ftp site: ftp.ccrs.nrcan.gc.ca/ftp/ad/CCRS_ARM/Satellites/, and are being transferred to the ARM data centre archive.

ReferenceLuo, Yi, Trishchenko, Alexander P., Latifovic, Rasim, Li, Zhanqing, Surface bidirectional reflectance and albedo properties derived using a land cover–based approach with Moderate Resolution Imaging Spectroradiometer observations. J. Geophys. Res., Vol. 110, No. D1, 2005.

Spectral albedo by ground measurement for various landcover types

MODISMODISSSFR aircraftSSFR aircraftGround obsGround obs

Landsat ETM+Landsat ETM+

ARESE-II Aerosol IOPARESE-II Aerosol IOP 20032003

3/1/

2003

4/1/

2003

5/1/

2003

6/1/

2003

7/1/

2003

8/1/

2003

9/1/

2003

10/1

/200

3

11/1

/200

3

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Alb

edo

Date

ECMWF CF box 3 MODIS Comparison of MODIS and

ECMWF albedo over the GCM

box centred at SGP CF. MODIS

data (in consistency with ground

observations) show diurnal cycle

of albedo and variations due to

sky-conditions (direct/diffuse ratio

and spectral distribution). Model

data lack such properties.

Satellite, airborne and ground comparison Satellite and GCM comparison