Yanmin Shuai, Jeffrey G. Masek, Feng Gao, Crystal B. Schaaf. (2010). An Algorithm for the Retrieval of 30-m snow-free albedo from Landsat surface reflectance and MODIS BRDF , submitted to RSE under reviewing

Update Landsat Albedo

Algorithm ReviewInputs:

Landsat surface reflectance, MODIS BRDF parameters and QA

Outputs: spectral/broadband albedo, nadir view reflectance

Model: MODIS BRDF model (RossThick-LiSparse-R)

Landsat Surface Reflectance

Unsupervised classification

Reprojection and

aggregation

Landsat scene Albedo

generation

Albedo-to-Nadir Ratio

Calculation

MODIS BRDF

MODIS QA

Landsat Spectral Albedo

Landsat Broadband Albedo

A

B

C

A. Processing chainB. MODIS informationC. Landsat albedo products

Legend of modules

Validation Sites

Station NameNetwor

kStation ID#

(Lat, Long)Major Land cover type

WRS-2path/row

Scenes used

Extended facility station #15

ARM EF1536.431°N, 98.284°W

Grassland 28/35 54

Desert rock stationSURFRA

DDRA

36.62320°N, 116.01962°W

Sparse vegetation

40/35 69

Table mountainSURFRA

DTBL

40.12557°N, 105.23775°W

Sandy with exposed rocks, sparse grasses

and shrubs

34/32 27

BondvilleSURFRA

DBON

40.05155°N,88.37325°W

Agriculture 23/32 46

Goodwin creekSURFRA

DGWN

34.2547°N, 89.8729 °W

Pasture grass and sparsely distributed

deciduous trees

23/36 57

Penn state university

SURFRAD

PSU40.72033°N,77.93100 °W

AgricultureResearch field

16/32 17

0.10 0.15 0.20 0.25 0.300.10

0.15

0.20

0.25

0.30

ARM EF15 (lnd) ARM EF15 (MOD)

DRA (lnd) DRA (MOD)

TBL (lnd) TBL (MOD)

Satellite retrieval (SW-Blue Sky Albedo)

Gro

un

d m

easu

res

(Alb

edo)

MODIS Representative Sites

y = 1.5815x - 0.0821 R² = 0.7575RMSE_mod_Rep=0.02540Bias_mod_Rep=-0.01928

Landsat Representative Sites

y = 0.967x + 0.019 R² = 0.911RMSE_lnd_Rep=0.01585Bias_lnd_Rep=-0.01298

0.10 0.15 0.20 0.25 0.30 0.350.10

0.15

0.20

0.25

0.30

0.35

BON (lnd) BON (MOD)

GWN (lnd) GWN (MOD)

PSU (lnd) PSU (MOD)

Satellite retrieval (SW-Blue Sky Albedo)

Gro

un

d m

easu

res

(Alb

edo)

Landsat Non-represen-tative Sites

y=1.1097x+0.0056

R² =0.7813RMSE_lnd_nonRep=0.03894Bias_lnd_nonRep=-0.02853

MODIS Non-representa-tive Sites

y=0.0051x+0.2036 R²=4E-06RMSE_mod_nonRep=0.06302Bias_mod_nonRep=-0.04912

PSU AlbedoUpperleft: Land surface white-sky albedo composite (NIR, Red, and Green bands to RGB) Upperright: MODIS white-sky albedo composite Lowerleft: Google MapsLowerright: scattering plot between Landsat (X-axis) and MODIS (Y-axis) albedo

Area: 30km by 30kmWRS-2 path 16 and row 32(PSU site)

Site ID#Landsat MODIS

Mean bias RMSE * R2 * Slope Mean bias RMSE * R2 * Slope

A

TBL -0.01204 0.01383 0.8310 0.9474 0.00353 0.01530 0.8480 1.0019

EF15 -0.01659 0.02015 0.8289 0.8929 -0.02557 0.02900 0.7751 1.5400

DRA -0.01075 0.01316 0.5814 0.7641 -0.02503 0.02739 0.1413 0.4979

A Representative sites -0.01298 0.01585 0.911 0.967 -0.01928 0.02540 0.7575 1.5815

B

GWN -0.02054 0.02579 0.4548 0.9736 -0.03529 0.03942 0.0484 0.3750

PSU -0.02977 0.03662 0.6115 1.0361 -0.03990 0.04745 0.1701 1.2666

BON -0.02869 0.03396 0.8126 1.0719 -0.06855 0.08769 *** ***

B Non-Representative sites -0.02853 0.03894 0.7813 1.1097 -0.04912 0.06302 *** ***

All six sites -0.0189 0.0266 0.7341 0.9617 *** *** *** ***

•R2 is a determination of the correlation coefficient from the linear regression using the “least square” method; Slope is the slope of regressed line.

0 100 200 300 400 500 600 700 800 900 1000 1100 12000.1

0.2

0.3

0.4

ARM EF15 (grd) ARM EF15 (lnd)

Date (YY-DDD)

Sho

rtw

ave

albe

do

03-00 03-100 03-200 03-300 04-00 04-100 04-200 04-300 05-00 05-100 05-200 05-300

Temporal albedo over ARM EF15 site (Grassland)

0 100 200 300 400 500 600 700 800 900 1000 1100 12000.1

0.2

0.3

0.4

DRA (grd) DRA (lnd)

Date (YY-DDD)

Sho

rtw

ave

albe

do

03-00 03-100 03-200 03-300 04-00 04-100 04-200 04-300 05-00 05-100 05-200 05-300

Temporal albedo over DRA site (Desert Rock, Sparse Vegetation)

Landsat Nadir BRDF-Adjustment Reflectance (NBAR)

Landsat surface reflectance 4, 3, and 2 composite (Color enhancement:WRS-2 p012r031, 2002-07-31

Landsat NBAR (band 4,3,2 combination)(Note: no retrieval in the water region)

NIR 0-0.5;Red 0-0.06; Green 0-0.006)

Difference between surface reflectance (directional) and nadir view reflectance

Difference between directional reflectance and NBAR for NIR band

Difference between directional reflectance and NBAR for Red band

Next …Snow-covered pixels (spatial extension)Beyond MODIS-era (temporal extension)

- BRDF shapes for snow-covered surface types- BRDF shapes for typical surface types

(surface type, date, NDVI, band, etc.)- Compatible land cover classification- Narrowband to Broadband conversion