Towards an Australian Root Zone Soil Moisture Product

Jeffrey Walker

Department of Civil and Environmental Engineering

The University of Melbourne

http://www.civenv.unimelb.edu.au/~jwalker

Importance of Soil Moisture

Early warning systems

Flood prediction – infiltration

Socio-economic activities

Agriculture – yield forecasting, management (pesticides etc), sediment transport

Water management – irrigation

Policy planning

Drought relief

Global change

Weather and climate

Evapotranspiration – latent and sensible heat

Climate Modelling

Knowledge of soil moisture has a greater impact on the predictability of summertime precipitation over land at mid-latitudes than Sea Surface Temperature (SST).

The Problem With LSMs

Same forcing and initial conditions but different predictions of soil moisture!

GCM Requirements & LSM Estimates

The Situation

Soil Moisture Modelling

Catchment-based LSM

Catchment Discretisation

Tier 1: Better Forcing

Observational Data Sets

NCAR Northern Hemisphere Sea Level Pressure

01/1899 – present; 5 x 5 degrees

Climate Research Unit (University of East Anglia) Temperature and Precipitation

01/01 - 12/98; 0.5 x 0.5 degrees

Center for Climatic Research (University of Delaware) Terrestrial Temperature and Precipitation

01/50 - 12/96 ; 0.5 x 0.5 degree

Global Precipitation Climatology Project (GPCP)

01/86 - 03/95; 2.5 x 2.5 degree

Langley Eight Year Shortwave and Longwave Surface Radiation Budget

07/83 - 06/91 - in process of being extended; 2.5 x 2.5 degree

Re-Analysis Atmospheric Forcing Data Sets

ECMWF Re-analysis Advanced Global Data

4x/day, 01/79 - 12/93

1.125 degrees (Gaussian)

NCEP/NCAR Re-analysis

4x/day, 01/48 – 12/99

2.5 x 2.5 degrees

Bias Correct Using Monthly Mean Observational Data Sets

Soil Moisture Modelling

Near-Surface Soil Moisture
Remote Sensing: Historic

Soil Moisture Coverage: Veg (Mean PR)

Tier 2: Assimilation

SMMR Assimilation

Root Zone Moisture Comparison

Comparison With NDVI Data

Drought of 1982/83

AMSR-E Validation

Australian Validation Sites

GRACE: Gravity Recovery And Climate Experiment

Study Area: Murrumbidgee

A Vision for the Future

Combination of:

Land surface modelling

Near-surface soil moisture remote sensing

Streamflow measurement

SASMAS

Changes in earth’s gravity field

GRACE


	Jeffrey Walker
	Department of Civil and Environmental Engineering
	The University of Melbourne


	http://www.civenv.unimelb.edu.au/~jwalker


	Early warning systems
		Flood prediction – infiltration
	Socio-economic activities
		Agriculture – yield forecasting, management (pesticides etc), sediment transport
		Water management – irrigation
	Policy planning
		Drought relief
		Global change
	Weather and climate
		Evapotranspiration – latent and sensible heat


	Knowledge of soil moisture has a greater impact on the predictability of summertime precipitation over land at mid-latitudes than Sea Surface Temperature (SST).


	Same forcing and initial conditions but different predictions of soil moisture!


Observational Data Sets
	NCAR Northern Hemisphere Sea Level Pressure
		01/1899 – present; 5 x 5 degrees
	Climate Research Unit (University of East Anglia) Temperature and Precipitation
		01/01 - 12/98; 0.5 x 0.5 degrees
	Center for Climatic Research (University of Delaware) Terrestrial Temperature and Precipitation
		01/50 - 12/96 ; 0.5 x 0.5 degree
	Global Precipitation Climatology Project (GPCP)
		01/86 - 03/95; 2.5 x 2.5 degree
	Langley Eight Year Shortwave and Longwave Surface Radiation Budget
		07/83 - 06/91 - in process of being extended; 2.5 x 2.5 degree

Re-Analysis Atmospheric Forcing Data Sets
	ECMWF Re-analysis Advanced Global Data
		4x/day, 01/79 - 12/93
		1.125 degrees (Gaussian)
	NCEP/NCAR Re-analysis
		4x/day, 01/48 – 12/99
		2.5 x 2.5 degrees

Bias Correct Using Monthly Mean Observational Data Sets


Combination of:
	Land surface modelling

	Near-surface soil moisture remote sensing
	Streamflow measurement
		SASMAS

	Changes in earth’s gravity field
		GRACE