Donald W. Cline National Operational Hydrologic Remote Sensing Center National Weather Service, NOAA CLPM Planning Workshop June 28-30 Fort Collins, Colorado

Donald W. ClineNational Operational Hydrologic Remote Sensing Center

National Weather Service, NOAA

CLPM Planning Workshop June 28-30 Fort Collins, Colorado

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• What is the Cold Land Processes Mission?– The Terrestrial Cryosphere– NASA Post-2002 Mission Planning & EX-7

• Mission Objectives– Major Science Questions– Measurement Goals

• Science Measurement and Modeling Requirements– Sensor Options: Type, Frequency, and Resolution– Modeling and Data Assimilation– Ground Segment Architecture

• Needed Pre-launch Science Investments– Science-oriented Trade Studies– Large Scale Airborne/Field Campaign

• Status of the Cold Land Processes Mission


• Cold areas of the Earth’s land surface where water is frozen either seasonally or permanently.

What is the Cold Land Processes Mission?

HydrologicFocus



• NASA Request for Information (RFI), April 1998– To develop a nominal mission scenario for 2003-2010– 100 responses

• reviewed by six NASA disciplinary panels

– Integrated into 23 mission concepts in three categories:• EOS follow-on Missions (EOS)

– for systematic measurement of critical parameters

• Earth Probe Missions (EX)– for exploratory research or focused process studies– included the Cold Land Processes Mission (EX-7)

• Operational Prototype Missions (OP)– for instrument development



• Earth Probe Missions (EX)– Each EX mission considered essential for advancement

of respective disciplines• No particular priority

– Intended to follow the model of Earth System Science Pathfinder (ESSP)

• Baseline mission descriptions allow science, technology, and programmatic planning

• Select missions as late as possible in implementation process to ensure latest science and technology issues are addressed.

• Missions not selected until science and technology are “mission-ready”



• Easton, MD Workshop (August, 1998) – 150 participants, in disciplinary and interdisciplinary

panels– Reviewed and amended the nominal mission

scenario– Report published November, 1998– Endorsed the nominal Cold Land Processes Mission

Concept• Measure snow water equivalent and frozen ground• SAR imaging techniques at moderate-high resolution

(1 km) with a short repeat cycle (3 days)



• Irvine, CA Workshop (April, 1999) – NASA Land Surface Hydrology Program convened a

workshop to refine three hydrology-related missions• 15 participants for EX-7

– Prepared EX-7 Science and Technology Implementation Plan

• Refined nominal mission concept• Identifies key science and technology

development/investments needed to become “mission-ready”

• http://www.nohrsc.nws.gov/cline/ex7_web/ex7_home.html


How does the extent of snow and frozen ground affectweather and climate?

Can the components of the terrestrial cryosphere be observedfrom space accurately enough to identify meaningfulclimatic trends?

To what extent can this information improve models of coldseason processes, hydrologic forecasts and forecasts ofhigh-latitude ecosystem functions?

To what accuracy can snow water equivalent be estimatedfrom remote sensing data, and is this sufficient forhydrologic applications?

Mission Objectives …Science Drivers


Mission Objectives

Determine the fundamental freeze/thawstate of the land surface.

Determine the physical characteristics of snow cover:snow extent, snow depth, snow density, and the

amount of free liquid water (snow wetness).

…Science Drivers


Science Measurement and Modeling Requirements

Synthetic Aperture Radar (SAR)Dual-frequency (L- and X-band)

Dual-polarization

Duty Cycle (Sensor Activation)All latitudes between 30oN-75oN

All elevations over 1000 m

ResolutionModerate Spatial (250 m - 1 km)

High Temporal (1-3 days)



Simultaneous MeasurementsRadar data for each frequency collected simultaneously

from the same spacecraft or from two spacecraftflown in formation.

InterferometrySensor configuration must support

cross-track interferometry.



Physical Modeling and Data AssimilationRequired to integrate remotely sensed information

and ancillary information in a comprehensive manner.

Ground Segment ArchitectureAlthough a research mission, demonstrate a clear path

to operational hydrology and meteorology.



At $400M, a dual-frequency dual-pol. SARis likely too expensive for NASA to put intoits own budget.

Three obvious cost reduction strategies:

InternationalPartnerships

DODBuy-down

SpecificationReduction



Single-Frequency SARLow-frequency only (e.g. L-band), similar spatial and

temporal resolutions and duty cycle. Suitable forfreeze/thaw status retrieval, but not snow retrieval.

Dual-Frequency Passive Microwave RadiometerDual-polarization 19 and 37 GHz, with moderate

spatial (1-5 km) and high temporal (1-3 days) resolution.

Combined Active/Passive MicrowaveSingle-frequency L-band SAR for freeze/thaw, plus

dual-frequency passive radiometer for snow.



NextSAR: LightSAR Legacy, Learning Experience

Market risks and potential returns on investments donot justify an industry investment in a science-focusedL-band only mission.

If commercial enhancements are added (e.g. dual-frequency, high-resolution), the market potentialincreases, but so do costs, market risks, anduncertainty.



Oil Spill Liability Trust Fund (OSLTF)

Petroleum industry interested in a dual-frequency (L-and X-band) dual-polarization SAR for oil spillmonitoring.

OSLTF provides an opportunity to co-fund $400M SAR mission with commercial partners.


Needed Pre-launch Science Investments

Snow AlgorithmsRetrieve snow properties with fewer SAR measurements.

(e.g. develop 2-frequency algorithms instead of 3-frequency algorithms)

Snow AlgorithmsEvaluate performance limits to snow detection and

measurement under wide range of conditions.

Freeze/Thaw AlgorithmsDevelop algorithms to partition freeze/thaw processes

between different land cover elements (e.g. soil).



Modeling and Data AssimilationStrategies needed to organize and analyze temporal

information retrieved from RS data(e.g. track changes in freeze/thaw status, use time series in algorithms)

Modeling and Data AssimilationStrategies needed to assimilate RS data directly intophysical land surface models, including developmentof appropriate snow models and an ability to predictbackscatter/emission using forward DMRT models.



Resolution RequirementsWhat are trade-offs of different spatial and temporalresolution options for both algorithm performance

(e.g. S/N) and for measurement applications?

Sensor RequirementsWhat are trade-offs of different sensor configurations?

Algorithm RequirementsWhat are trade-offs of different algorithms on

measurement accuracy/confidence, geographicapplication, and data processing?


Critical for Science Development

A comprehensive ground truth database that hasconsistency across all locations of field campaigns is

required to support investigations pursuing thescience questions.



Comprehensive in Scope

The lack of wide variation in snow cover properties,land cover, and terrain in testing current algorithms hasprevented a thorough determination of the accuracy and

suitability of different approaches.



Multi-sensor, Multi-purpose, Legacy Dataset

Simultaneous RS observations from active, passive, andoptical sensors, combined with intensive ground

observations and distributed modeling informationwill provide the basis for firming up candidate

candidate algorithms and sensor options.



Understanding Earth System Change,NASA’s Earth Science Enterprise Research Strategy

2000-2010 (Draft)

Status of the Cold Land Processes Mission

…exploratory observations ofsoil moisture, snow accumulation,and freeze/thaw transitions…will provide critical process-levelinformation...

New active and passive remotesensing techniques from spacemay lead to global observationsof soil moisture, snow waterequivalent, freeze-thaw transitions,...


Understanding Earth System Change,NASA’s Earth Science Enterprise Research Strategy

2000-2010 (Draft)

Status of the Cold Land Processes Mission

Quantitative understanding ofhydrologic processes over largeareas…will require a breakthroughin large-scale observation ofhydrologic properties...

Specific observational requirements toaddress this problem include…exploratory measurements of soilmoisture, snow accumulation, and thetransition between frozen and thawedsoil conditions.

Documents

Donald W. Cline National Operational Hydrologic Remote Sensing Center National Weather Service, NOAA CLPM Planning Workshop June 28-30 Fort Collins, Colorado