A JPL / GSFC Partnership for an Earth Science Decadal Survey Mission

Peggy O’Neill, NASA / GSFC / 614.3September, 2008 NAFE Workshop, Melbourne, Australia

A JPL / GSFC Partnership for an

Earth Science Decadal Survey

Mission

Soil Moisture Active and Passive (SMAP) Mission


OutlineOutline

• SMAP science – why do we care about soil moisture & FT

• NRC Decadal Survey impetus

• SMAP science objectives

• Mission & instrument concept

• SMAP science products & synergy


Dry Soil

Moist Soil

5°C

May 10 : Clear w/ scattered cirrus & mild winds

May 18: 90 mm Rain

May 20: Clear sky & mild winds

CASES’97, BAMS (81), 2000.

Soil Moisture Controls Land / Atmosphere InteractionsSoil Moisture Controls Land / Atmosphere Interactions

(Cahill et al., 1999)

• Soil moisture is an important land surface control on water and energy fluxes.

• A soil moisture mission will help answer:

-- do climate models correctly represent land surface / atmosphere interactions?

-- what are the water resources and water availability impacts of global climate change?

Water and Energy Cycle

Impact on Atmosphere


Predictability of seasonal climate is dependent on boundary conditions such as sea surface temperature (SST) and soil moisture – soil moisture is particularly important over continental interiors.

Difference in Summer Rainfall: 1993 (flood)

minus 1988 (drought) years

Observations

Simulation driven by SST and soil moistureSimulation driven just by SST

-5 0 +5 Rainfall Difference [mm/day]

(Schubert et al., 2002)

New space-based soil moisture observations and data assimilation modeling can improve forecasts of local storms and seasonal climate anomalies

With Realistic Soil Moisture

24-Hours Ahead High-Resolution

Atmospheric Model Forecasts

Observed Rainfall0000Z to 0400Z 13/7/96(Chen et al., 2001)

Buffalo CreekBasin

High resolution soil moisture data High resolution soil moisture data will improve numerical weather will improve numerical weather prediction (NWP) over continents by prediction (NWP) over continents by accurately initializing land surface accurately initializing land surface statesstates

Without Realistic Soil Moisture

NWP Rainfall Prediction

Seasonal Climate Predictability

Value of Soil Moisture Data to Weather and ClimateValue of Soil Moisture Data to Weather and Climate


Terrestrial Water, Energy and Carbon Cycle ProcessesTerrestrial Water, Energy and Carbon Cycle Processes

Landscape Freeze/Thaw Dynamics Drive Boreal Carbon Balance

[The Missing Carbon Sink Problem].

Carbon Cycle

Are Northern Land Masses Sources or Sinks for Atmospheric Carbon?

Mean growing season onset for 1988 – 2002 derived from coarse resolution SSM/I data

SMAP will provide important information on the land surface processes that control land-

atmosphere carbon source/sink dynamics. It will provide more than 8-fold increase in spatial resolution over existing spaceborne sensors.


Flood and Drought ApplicationsFlood and Drought Applications

“…delivery of flash-flood guidance to weather forecast offices are centrally dependent on the availability of soil moisture estimates and observations.”

“SMAP will provide realistic and reliable soil moisture observations that will potentially open a new era in drought monitoring and decision-support.”

Decadal Survey:

Current: Empirical Soil Moisture Indices Based on Rainfall and Air Temperature ( By Counties or ~30 km )

SMAP Capability: Direct Soil Moisture Observations – global, 2-3 day revisit, 10 km resolution

Current NWS Operational Flash Flood Guidance (FFG)

Current Operational Drought Indices by NOAA and National Drought Mitigation Center (NDMC)


NRC SMAP ExpectationsNRC SMAP Expectations

“…the SMAP mission is ready for “fast-track” towards launch as early as 2013, when there are few scheduled Earth missions. The readiness of the SMAP mission also enables gap-filling observations to meet key NPOESS community needs (soil moisture is “Key Parameter,” see 4.1.6.1.6 in IORD-II Document).”

Decadal Survey Panels Cited SMAP Applications

Water Resources and Hydrological Cycle1. Floods and Drought Forecasts2. Available Water Resources Assessment3. Link Terrestrial Water, Energy and Carbon Cycles

Climate / Weather 1. Longer-Term and More Reliable Atmospheric Forecasts

Human Health and Security1. Heat Stress and Drought2. Vector-Borne and Water-Borne Infectious Disease

Land-Use, Ecosystems, and Biodiversity

1. Ecosystem Response (Variability and Change)2. Agricultural and Ecosystem Productivity3. Wild-Fires4. Mineral Dust Production

SMAP is one of four missions recommended by the NRC Earth Science Decadal Survey for launch

in the 2010-2013 time frame


NASA SMAP Workshop (July 2007) NASA SMAP Workshop (July 2007)

Key Workshop Conclusions (Executive Summary):

• There is a stable set of instrument measurement requirements for SMAP that are traceable to science requirements for soil moisture and freeze/thaw.

• The baseline SMAP instrument design is capable of satisfying the science measurement requirements.

• Significant heritage exits from design and risk-reduction work performed during Hydrosphere State (Hydros) mission formulation and other technology development activities.

• Heritage and lessons learned can be leveraged from the Aquarius project. This heritage includes both the L-Band radiometer and radar electronics.

• There are no technology “show-stoppers”, and SMAP formulation is positioned to begin where Hydros left off.

http://hydrology.jpl.nasa.gov/missions/SMAP/


Global mapping of Soil Moisture and Freeze/Thaw state toGlobal mapping of Soil Moisture and Freeze/Thaw state to:

Understand processes that link the terrestrial water, energy & carbon cycles

Estimate global water and energy fluxes at the land surface

Quantify net carbon flux in boreal landscapes

Enhance weather and climate forecast skill

Develop improved flood prediction and drought monitoring capability

SMAP Science ObjectivesSMAP Science Objectives

Primary Controls on Land Evaporation and

Biosphere Primary Productivity

Freeze/Thaw

Radiation

Soil Moisture


SMAP Mission ConceptSMAP Mission Concept

• Orbit:

− Sun-synchronous, 6 am/pm orbit

− 670 km altitude

• Instruments:

− L-band (1.26 GHz) radar

◦ High resolution, moderate accuracy soil moisture

◦ Freeze/thaw state detection

◦ SAR mode: 3 km resolution

◦ Real-aperture mode: 30 x 6 km resolution

− L-band (1.4 GHz) radiometer

◦ Moderate resolution, high accuracy soil moisture

◦ 40 km resolution

− Shared instrument antenna

◦ 6-m diameter deployable mesh antenna

◦ Conical scan at 14.6 rpm

◦ incidence angle: 40 degrees

− Creates contiguous 1000 km swath

− Swath and orbit enable 2-3 day revisit

• Mission Development Schedule Phase A start: September

2008 SRR/MDR: February

2009 PDR: December

2009 CDR: December

2010 SIR: October

2011 Instrument Delivery April 2012 LRD: March 2013

• Mission operations duration: 3 years


Mission Implementation ApproachMission Implementation Approach

• Mission partners: JPL and GSFC

Potential non-NASA partnerships

• Leverage knowledge from Hydros studies

• Science Team selected competitively by NASA

• Radar provided by JPL

• Radiometer provided by GSFC

• Maximize Aquarius heritage

• Shared antenna and spin assembly procured from industry

• Instrument data processing shared between JPL and GSFC

• Spacecraft developed in-house at JPL• Launch vehicle: Minotaur IV based on DoD

use of SMAP data


SMAP Instrument ConceptSMAP Instrument Concept

1000 km

Nadir gap in high res radar data: 200-300 km

• Radiometer measurements:– 40 km real-aperture resolution

– Made over 360 deg of scan

– Form full contiguous swath of 1000 km

– Collected continuously; AM/PM, over land and over ocean

• “Low res” radar measurements:– 30 x 6 km real-aperture “slices”

– Made over forward and aft portions of scan

– Form full contiguous swath of 1000 km

– Collected continuously, AM/PM, over land and over ocean

• “High res” radar measurements:– Used to generate 1 km gridded product, can

be further averaged up to 3 km and 10 km.

– Made over forward 180 deg of scan only (optional 360 deg collection possible)

– 1000 km swath with nadir gap of 200-300 km astride spacecraft ground track

– Collection programmable; baseline to collect over land during AM portion of orbit only

• Orbit: 670 km, sun-synchronous, 6 pm LTAN

• Instrument Architecture: Radiometer and radar share rotating 6 meter diameter reflector antenna

• Antenna Beam: 14.6 rpm rotation rate, 40 deg incidence angle


SMAP Coverage StrategySMAP Coverage Strategy

Radiometer,Low-Res Radar

High-Res Radar

• Three orbit sample shown in image above.

• Low-res radiometer and low-res radar: Using AM revs only, cover entire Earth in 3-days. Average revisit time improves when AM + PM passes are used (but Faraday rotation becomes an issue).

• High-res radar data collection is programmable via ground command. Average revisit time is 3-days over land when only AM revs are used.


• Key antenna requirements– Dual-pol L-Band feed

– < 2.6 deg BW at 1.4 GHz, >90% beam efficiency.

– 14.6 rpm rotation rate

– Deployable mesh material, high reflectivity at L-Band

– Pointing: 0.3º stability, 0.1º knowledge

– Rotational Inertia < 150 kg-m^2, CG to 2.5 cm, Inertia Cross Products < 1%, Stiffness > 1 Hz.

• During Hydros risk reduction, two antenna vendors were funded to study adaptations of heritage reflector designs for rotation.

– “Radial Rib” design with fixed central boom and rotating reflector.

– “Perimeter Truss” design with rotating reflector and boom.

SMAP antenna RFP will have a requirement of no boom blockage

Rotating ReflectorRotating Reflector


Level 1 Baseline and Minimum RequirementsLevel 1 Baseline and Minimum Requirements

Baseline Mission Minimum MissionSoil Moisture Measurement*

Provide estimates of soil moisture in the top 5 cm of soil with an accuracy of 4% volumetric at 10 km resolution and 3-day average intervals

Provide estimates of soil moisture in the top 5 cm of soil with an accuracy of 6% volumetric at 10 km resolution and 3-day average intervals

Freeze/Thaw Measurement

Provide binary estimates of surface transitions in region north of 45°N with a classification accuracy of 80% at 3 km resolution and 2-day average intervals

Provide binary estimates of surface transitions in region north of 45°N with a classification accuracy of 70% at 10 km resolution and 3-day average intervals

Mission Duration

At least 3 years At least 1 year

* Excludes forests (regions with vegetation water content greater than ~5 kg/m2) and urban / mountainous areas


Science L1 RequirementsScience L1 Requirements

Baseline Mission Duration Requirement is 3 Years (Decadal Survey)

RequirementHydro-

MeteorologyHydro-

ClimatologyCarbon Cycle

Baseline Mission Minimum Mission

Soil Moisture

Freeze/ Thaw

Soil Moisture

Freeze/Thaw

Resolution 4-15 km 50-100 km 1-10 km 10 km 3 km 10 km 10 km

Refresh Rate 2-3 days 3-4 days 2-3 days(1) 3 days 2 days(1) 3 days 3 days(1)

Accuracy 4-6% 4-6% 80-70% 4% 80% 6% 70%

(1)North of 45°N latitude


Baseline Science Data ProductsBaseline Science Data Products

Data Product Description

L1B_S0_LoRes Low Resolution Radar σo in Time Order

L1C_S0_HiRes High Resolution Radar σo on Earth Grid

L1B_TB Radiometer TB in Time Order

L1C_TB Radiometer TB on Earth Grid

L2/3_F/T_HiRes Freeze/Thaw State on Earth Grid

L2/3_SM_HiRes Radar Soil Moisture on Earth Grid

L2/3_SM_40km Radiometer Soil Moisture on Earth Grid

L2/3_SM_A/P Radar/Radiometer Soil Moisture on Earth Grid

L4_F/T Freeze/Thaw Model Assimilation on Earth Grid

L4_SM_profile Soil Moisture Model Assimilation on Earth Grid

Global Mapping L-Band Radar and Radiometer

High-Resolution and Frequent-Revisit

Science Data

Observations + Models =Value-Added Science Data


100 km 10 km 1 km

Day

Week

Month ALOS SAR

Aquarius

SMOS SMAP Radar-Radiometer

Climate ApplicationsClimate Applications

Weather ApplicationsWeather Applications

Carbon CycleCarbon Cycle ApplicationsApplications

Resolved Spatial Scales

Res

olve

d T

emp

oral

Sca

les

Radio

met

er

RadarEvolution of L-Band Sensing

SMAP Mission UniquenessSMAP Mission Uniqueness


SMAP Synergy With Other Missions/ApplicationsSMAP Synergy With Other Missions/Applications

SMAP provides continuity for L-band measurements of ALOS, SMOS, and Aquarius, and synergy with GPM and GCOM-W

SMAP soil moisture and co-orbiting GPM precipitation data will improve surface flux estimates and flood forecasts (Crow et al., 2006)

SMAP also benefits GPM by providing surface emissivity information for improved precipitation retrievals

0

0.2

0.4

0.6

0.8

1

1.2

2006 2008 2010 2012 2014 2016 2018 2020

SMAP

GPM

GCOM-W

Aquarius

SMOS

ALOS

RM

S E

rro

r in

La

ten

t H

ea

t F

lux

[W m

-2]

Frequency of Rainfall Observations [day-1]

Potential reduction in GPM-estimated latent

heat flux error by assimilation of SMAP soil moisture in land

surface model (LDAS)

SMAP 3-day sampling

Estimated Mission Timeline


Examples of Combined L-Band Sensor SystemsExamples of Combined L-Band Sensor Systems

Tower-BasedTower-Based Aircraft-BasedAircraft-Based


SMAP Major Field CampaignsSMAP Major Field Campaigns

Year/Quarter

1 2 3 4

2008 SMAPVEX08

2009 SMOSSMOS AustraliaGermany

Spain

Australia

2010 Australia AquariusAquariusAustralia

SMAPVEX10

Germany, Spain

SMAPVEX10

2011 SMAPVEX11

2012

2013 SMAPSMAP SMAPVEX13

2014 SMAPVEX14

2015

• SMAPVEX08• High priority design/algorithm issues

• Australia 2009-2010• 4 one-week campaigns to span four seasons

• J. Walker aircraft radiometer (PLMR) and new radar (PLIS)

• Separate SMOS validation

• SMAP SDT participation

• Germany/Spain 2009-2010• SMOS validation…launch delays possible

• Can we get a European group to add L-band radar (DLR)?

• SMAP SDT participation

• SMAPVEX10: CLASIC• Spring-Summer 2010

• Oklahoma

• SMOS and Aquarius available

• Focus of algorithm validation

• SMAPVEX11• Focus on different problems: F/T, regions,

seasons

• SMAPVEX13 and 14• SMAP product validation

Satellite Launch in RedSatellite Launch in Red


Applications and User EngagementApplications and User Engagement

Droughts Floods/Landslides Agriculture Weather/Climate Human Health

• By providing direct measurements of soil moisture and freeze/thaw state, SMAP will enable a variety of societal benefits:

• Near-term SMAP applications outreach will be focused on: 1. Developing a community of end-users, stakeholders, and decision makers that

understand SMAP capabilities and are interested in using SMAP products in their application (SMAP Community of Practice).

2. Developing an assessment of current application benefits / requirements and needs for SMAP products (survey).

3. Identifying a handful of “early adopters” who will partner to optimize their use of SMAP products, possibly even before launch as part of the extended OSSE activities (“targeted partners”).

4. Providing information about SMAP to the broad user community



Project OverviewProject Overview

http://smap.jpl.nasa.gov/

Primary Science ObjectivesGlobal, high-resolution mapping of soil moisture and its

freeze/thaw state to: Link terrestrial water, energy and carbon cycle processes Estimate global water and energy fluxes at the land surface Quantify net carbon flux in boreal landscapes Extend weather and climate forecast skill Develop improved flood and drought prediction capability

SMAP is a first-tier mission recommended by 2007 NRC Earth Science Decadal Survey

Mission Implementation:

Partners • JPL (project & payload mgmt, science, spacecraft, radar, mission operations, science processing)

• GSFC (science, radiometer, science processing)

Risk • 7120.5D Category 2; 8705.4 Payload Risk Class C

Launch • March 2013, Minotaur IV

Orbit • Polar sun-synchronous; 670 km altitude

Life • 3 years

Payload • L-band SAR (JPL)• L-band radiometer (GSFC)• Shared 6 m rotating (14.6 rpm) antenna (industry)

Documents

A JPL / GSFC Partnership for an Earth Science Decadal Survey Mission