MoistureMap: Mixed-pixel Retrieval

Ye NanMaster of researchUniversity of Melbourne

Jeffrey Walker, Dongryeol Ryu, Christoph Rüdiger, Robert Gurney, Edward Kim, Yann Kerr

NAFE’06 Study Area-Kyeamba catchmentNAFE’06 Study Area-Kyeamba catchment

Heterogeneity in SMOS resolution pixel

Standing waterStanding waterForestForest

Urban areaUrban area

GrassGrass

Bare soilBare soil

CropsCrops

Source: http://maps.google.com.au

50km50km

50km50km

South Paris, FranceSouth Paris, France

World-wide Problem

Pennsylvania, USAPennsylvania, USA

Source: http://maps.google.com.au

Xinjiang, ChinaXinjiang, China

““as little as 3% standing water as little as 3% standing water

coverage leads to more than 4%v/v coverage leads to more than 4%v/v

error in derived soil moisture – the error in derived soil moisture – the

target accuracy for SMOS soil target accuracy for SMOS soil

moisture retrieval“ moisture retrieval“

[Walker et al., 2006] [Walker et al., 2006]

Effect of mixed-pixels

The heterogeneity of pixels reduce the accuracy The heterogeneity of pixels reduce the accuracy

of SMOS soil moisture retrievalof SMOS soil moisture retrieval

Simulating the surface types emission contributions on Simulating the surface types emission contributions on

overall SMOS microwave responseoverall SMOS microwave response

Project target and proposed approach

Area distribution pie mapArea distribution pie mapBrightness temperature mapBrightness temperature map

1SMOS Water Crops ForestB B Water B Crops B Forest

SMOS

T T A T A T AA

Rocks Bare Grass UrbanB Rocks B Bare B Grass B UrbanT A T A T A T A

Proposed Approaches

irepresents different surface

SMOS

iB

i SMOS

AT

A iB

T

SMOSSMOS Land-useLand-use

Bare soil, Crops Bare soil, Crops

and Grassand Grass

ForestForest

UrbanUrban

WaterWater

RocksRocks

Tau-Omega Tau-Omega

modelmodel

LAI_maxLAI_max

Klein, Stogryn, DebyeKlein, Stogryn, Debye

5.7 0.074Rocks i

Test field

Goulburn River catchment Goulburn River catchment

NAFE’05 data setNAFE’05 data set

Test field

Yanco areaYanco area

NAFE’06 data setNAFE’06 data set

Test field

Kyeamba catchment Kyeamba catchment

NAFE’06 data setNAFE’06 data set

Research direction

Develop the approaches to simulate microwave radiation of standing water, rocks and urban area.

Evaluate the effect of forest, standing water, rocks and urban area on overall brightness temperature.

Establish the mixed-pixel model to retrieve soil moisture from SMOS data.