# Presentation: 869409

## Science Questions

- Societal Relevance

- Observational Requirements

- Observational Strategies

- Satellite Missions

**Scientific Basis for NASA OBB**** ****Mission Planning**

## Emerging Scientific Questions for NASA OBB Program

**Emerging Scientific Questions for NASA OBB Program**

**How are ****ocean ecosystems**** and the ****biodiversity**** they support influenced by climate or environmental variability and change, and how will these changes occur over time?**
**How do ****carbon and other elements**** transition between ocean pools and pass through the Earth System, and how do these biogeochemical fluxes impact the ocean and Earth’s climate over time?**
**How (and why) is the diversity and geographical distribution of**** ****coastal marine habitats ****changing, and what are the**** ****implications for the well-being of ****human society****?**
**How do ****hazards**** ****and pollutants impact the hydrography and biology of the coastal zone? How do they affect**** ****us,**** ****and can we**** ****mitigate**** ****their effects?**

## Ecosystems & Diversity, Carbon & Biogeochemistry, Habitats & Hazards

-  Changes in ocean ecosystem structure, 	function & distribution on synoptic	to climatic time scales
-  Impacts on higher trophic levels (e.g., 	fish, reptiles, birds, mammals)
-  **Science**:
-  Ocean biogeography
-  Quantify productivity &its  transfer to 	higher trophic levels
-  Identifying plankton functional groups
-  **Benefits to society**:
-  Assessing ecosystem health, services
-  Understanding nutrient and carbon 	sinks/sources
-  Improving human welfare

**Ecosystems & Diversity,**** Carbon & Biogeochemistry,** **Habitats & Hazards**

## Ecosystems & diversity, Carbon & Biogeochemistry, Habitats & Hazards

-  **Relevance**:
-  Impacts and feedbacks of climate 	changes on biogeochemistry
-  Impacts of humans
-  **Science**:
-  Ocean carbon pools & fluxes
-  Primary producer biomass
-  Understanding climate controls and the role
- 	of ocean biogeochemistry
-  **Benefits to society**:
-  Assessing/verifying ocean carbon 	credit trading, mitigation strategies
-  Helping manage climate and adapting to
- 	change

**Ecosystems & diversity, ****Carbon & Biogeochemistry,** **Habitats & Hazards**

## Ecosystems & diversity, Carbon & Biogeochemistry, Habitats & Hazards

-  Growing human population density and 	dependence on ocean resources
-  Changing coastal environments
-  **Science**:
-  Classification of regional marine 	habitats and 	coastal landscapes
-  Measuring impacts of land use
-  Understanding climate impacts & controls
-  Sustainable fisheries and coastal ecosystems
-  Assessing red tides and coral reef health
-  **Benefits to society**:
-  Basis for ecosystem-based management
-  Improving human health, recreation, and 	commerce

**Ecosystems & diversity, Carbon & Biogeochemistry,** **Habitats**** & Hazards**

## Ecosystems & diversity, Carbon & Biogeochemistry, Habitats & Hazards

-  Significant risk to human life and property
-  Protection of natural environments
-  **Science**:
- - *Acute Hazards*:
-  Tsunamis & hurricanes
-  Oil Spills
-  Harmful algal blooms
- - *Chronic Hazards*:
-  Ocean warming and sea level rise
-  Ocean acidification
-  Eutrophication
-  **Benefits to society**:
-  Forecasting of hazards
-  Disaster preparedness/security
-  Mitigation tools

**Ecosystems & diversity, Carbon & Biogeochemistry,** **Habitats & ****Hazards**

## Ecosystems & Diversity, Carbon & Biogeochemistry, Habitats & Hazards

-  **Accurately determine ecosystem biomass**
- Accurate detection of long-term changes
- 	Atmospheric correction...
- 	Calibration / validation...
- Separate optically active components
- 	CDOM from Chl...
- Global coverage sampling all biomes
-  **Assess biodiversity**
- Phytoplankton functional groups
- Special  phytoplankton species
- Particle size spectrum
-  **Measure ocean productivity **
- NPP rate determinations
- Physiological status of phytoplankton community
- Grazing & secondary production
-  **Understand the oceanographic setting**
- MLD, incident and in situ light levels, SST, SSS, sea level, vector winds, ...

**Ecosystems & Diversity,**** Carbon & Biogeochemistry,** **Habitats & Hazards**

**Notes:**
First, we need to determine ecosystem biomass over ocean scales. The chlorophyll content of plant cells can change in response to light and nutrient stresses.  Further, non-living compounds like dissolved organic materials can mask the signals of chlorophyll and change the color of the ocean. Accurate scientific assessments of phytoplankton biomass require understanding and routine observation of competing optical signals.  All these observations must be accurate enough to enable the assessment of changes over timescales of decades.
Second, in order to provide the scientific basis to sustain the health of our oceans, the biodiversity of ocean ecosystems must be quantified and monitored over time.  To a first order, this can be done by quantifying concentrations of important phytoplankton functional groups (e.g., diatoms, coccolithophore, Trichodesmium, etc.).  Other relevant measures of community diversity are determinations of the particle size spectra, abundances of different phytoplankton size classes and the relative contribution that non-living materials make to the absorption of light. We also need to develop the capability to predict the impact of these changes on higher trophic levels through ecosystem models.
Third, to understand how the ocean cycles elements and how much food and energy can be provided by ocean ecosystems we need to assess the ocean's net primary production (NPP) and monitor indices of ecosystem health.  Some models to assess past and present NPP are available, but they have large uncertainties. Our models lack predictive skill. We need to implement a strategy that merges satellite data into in situ observing systems and research observatories, numerical modeling.  In particular, novel space-based technologies, including lidar-stimulated phytoplankton fluorescence, are required to measure the physiological status and health of marine ecosystems.
Ecosystems are dynamic entities in an ever-changing ocean. Thus to understand ocean ecosystems, we must fully understand the physical environment. Satellite measurements incident solar radiation and its spectral components, sea surface height, vector winds, sea surface temperature and surface currents are important complements to proper assessments of marine ecosystems

## Ecosystems & diversity, Carbon & Biogeochemistry, Habitats & Hazards

**Ecosystems & diversity, ****Carbon & Biogeochemistry,** **Habitats & Hazards**

-  **Observational requirements**:
-  **Accurate assessment of ocean BGC constituents**
- Accurate detection of long-term changes
-       Atmospheric correction...
-       Calibration / validation...
- Separate optically active components
-       CDOM from Chl...
- Measure particle biomass
-  **Assess ocean productivity & carbon fluxes**
- Net primary production
- New & secondary production
- Physiological status of phytoplankton community
-   **Integrate with biogeochemical models**
- Air-sea CO2 fluxes
- Carbon export by both sinking & physical pumps
- Shelf carbon exchanges

**Notes:**
Quantifying, monitoring, and predicting changes in ocean elemental cycles and their interactions with atmospheric and terrestrial systems requires information on stock sizes and key transformation rates.  Advanced ocean remote sensing missions must address atmospheric correction issues associated with absorbing aerosols, improve the separation of optically active in-water, enable a broad-scale characterization of unique ecosystem conditions (e.g., separating iron- and nitrogen-limited waters), and provide appropriate space and time scale observations for interdisciplinary approaches to quantifying elemental fluxes at the land-ocean interface.
As ocean remote sensing science evolves from simple empirical algorithms to higher-order spectral matching models, accuracy and precision demands on retrieved water leaving radiances will escalate.  Consequently, future observations must include extensive pre-launch sensor characterizations and post-launch calibration capabilities.  Importantly, atmospheric contributions to top-of-atmosphere radiances exceed 90% and demand significantly improved approaches for accurate removal.  In particular, information on absorbing aerosol type, column thickness, and vertical distribution is critical.  New strategies are needed to improve corrections over coastal ‘bright waters’ as well, where water leaving radiance contributions cannot be assumed negligible for the traditional near-infrared atmospheric correction bands.  To advance our understanding of ocean elemental cycles, we simply cannot continue the conventional atmospheric correction approach in perpetuity.  In some cases, dedicated sensors for atmospheric measurements will be necessary to realize ocean science goals and historical barriers will need to be breached between the ocean and atmospheric science communities to integrate this new information.
While unparalleled water leaving radiance accuracies are fundamental to future remote sensing observations, they are not enough.  Classic ‘ocean color’ bands were not optimized for spectral matching algorithms and are not adequate for fully resolving the multitude of unique optical properties associated with specific in-water constituents.  Enhanced measurement capabilities are necessary, both in spectral range and spectral resolution.  Active approaches (i.e., lidar) can provide independent measures of critical elemental stocks.  For example, lidar sub-surface light scattering profiles can yield important information on particle biomass abundance.  Focused studies on the land-ocean interface will also require increased spatial resolution (<100 m).  Phytoplankton growth rates based on satellite-derived chlorophyll:carbon ratios
Global description of key transformational rates is perhaps the greatest challenge in resolving elemental cycles.  Observations of central physical forcings (e.g., dust deposition, incident light, mixed layer depth, SST, etc) can function as a basis for mechanistic models of rate terms or simply may provide important supporting information.  For the carbon cycle, the most accessible transformation rate is net primary production, but it requires description of physiological variability.  Passive remote sensing retrievals of phytoplankton chlorophyll:carbon ratios provide one approach to assessing physiological variability.  Effectively implementing such an index requires additional information on regional differences in the nature of nutrient stress (e.g., iron vs. nitrogen).

While the remote sensing of stocks and rates clearly has a central role to play, characterizing and quantifying ocean elemental cycles is complex and truly an interdisciplinary problem.  Accordingly, all national and many international science agencies are developing programs to contribute uniquely to the problem.  Integrating NASA’s effort with these concurrent efforts and field programs (e.g., NACP, ORION, NEON, GOOS) is essential to the success of the Carbon and Biogeochemistry program.  This interaction must entail not only shared observational capabilities and data sets, but synergistic contributions to the development of Earth system models. 

## Ecosystems & diversity, Carbon & Biogeochemistry, Habitats & Hazards

-  **Assess in-water constituents in coastal environments**
- Accurate detection of long-term changes
-       Atmospheric correction...
-       Calibration/sensor characterization...
- Separate optically active components
-       CDOM from Chl...
- Develop capabilities for all biomes – globally
-  **High temporal resolution**
- Within a day revisit time – tidal phenomena
-  **High spatial / spectral resolution**
- Use existing/upcoming technologies (LDCM, ...)
- New high resolution ocean color capability
- 	10 m – 100 km swath - 20 ocean color bands
-  **Understand the coastal ocean setting**
- Land-ocean interactions – river outflows
- Tidal & coastal fronts
-  **Couple with in situ observations**
- Ocean observatories
- Sub-orbital AUV vehicles

**Ecosystems & diversity, Carbon & Biogeochemistry,** **Habitats**** & Hazards**

**Notes:**
A range of space-based observation technologies and models need to be developed over next 25 years to advance our understanding of coastal habitats through rigorous tests of hypotheses and sensitivity analyses. Foremost are the requirement to obtain frequent and synoptic observations of small-scale phenomena in both aquatic and adjacent land environments, and developing a workforce capable of using advanced observing technologies to develop new knowledge. Significant progress can be made by linking research to operations in developing decision-support tools for coastal managers and policy makers.
The technological challenge lies in observing key biogeochemical (colored Dissolved Organic Matter, chlorophyll, phytoplankton functional groups and physiology, suspended load, bottom type) and physical (temperature, salinity, wind, circulation, bathymetry, light attenuation) parameters, and discriminating between long-term and short-term (daily to weekly) change, at medium spatial resolution (10 to 100 m), and within the topographic and bathymetric regime of coastal habitats (watershed to about 20 m depth). Models need to simulate such variability and processes at these small time and space scales, and help understand linkages between lower and higher trophic levels including living marine resources used commercially, for recreation, or cultural purposes. NASA's research of coastal habitats will contribute significantly to, and benefit from, efforts conducted through the National Science Foundation's ORION program and the coastal components of the IOOS and GEO.
Historical oceanographic satellite sensors have had limited utility in studying or monitoring coastal zones, because of their coarse ground resolution in few and relatively broad spectral bands. The Landsat-class sensors (Landsat, SPOT, Ikonos, Quikbird, etc.) that provide higher spatial resolution have limited sensitivity and are unable to detect the subtle changes in reflectance required to map changes in depth and to differentiate components of coastal aquatic habitats. Further, coastal aquatic environments require innovative techniques to correct imagery for atmospheric effects.
Coastal habitat research and assessments will require a strategy that incorporates active and multispectral passive observations, and global and local measurement capabilities. This requires complementing the capabilities of the NPP and NPOESS missions with advanced Landsat-class missions that provide frequent, highly sensitive observations at higher spectral resolution. Coastal observing will require sensors that can dwell on dark targets and illuminate them with advanced lidar. Observations need to be consistent and calibrated, accessible, and well-documented. 

## Ecosystems & diversity, Carbon & Biogeochemistry, Habitats & Hazards

**Ecosystems & diversity, Carbon & Biogeochemistry,** **Habitats & ****Hazards**

-  **Observational requirements**:
-  **Respond to acute hazards**
- Instantaneous data dissemination
- Rapid revisit cycle
- All weather capabilities –> SAR/UAV’s
-  **Assess chronic hazards**
- Accurately measure ecosystem parameters
-  	Atmospheric correction...
-       Calibration/sensor characterization...
- Separate optically active components
-       CDOM from Chl...
** ****High temporal resolution**
- Rapid revisit cycle – follow events
- Use temporary platforms (sub-orbital assets)
-  **High spatial resolutions**
- Use existing/upcoming technologies (LDCM, ...)
- New high resolution ocean color capability
- 	10 m – 100 km swath

**Notes:**
Quantifying sea level rise, coastal erosion, and plumes of suspended material, dense algae, or toxins requires higher temporal, spatial, and spectral resolution imagery than currently available.  New atmospheric correction approaches must be developed to deal with significant amounts of near-infrared reflectance and absorbing aerosols common to coastal regimes.  Research is needed to develop algorithms that are not merely site-specific empirical regressions, but can determine the quantity and composition of suspended materials.  Integrated modeling and data assimilation efforts will be required to tie together in situ measurements and a variety of remote sensing data including sea surface temperature and bathymetry.   
Evaluating the impact of chronic hazards on marine ecosystems requires extensive modeling efforts to understand how surface processes that can be monitored from space relate to the chemistry,   biology, and geology of the oceans.  Linkages must also be made between processes at the sea surface and the vertical structure of the oceans.   
We propose that three different technologies be developed for assessing coastal hazards.  These include: 
1) Multi-spectral high spatial resolution imager
2) Portable sensors from suborbital platforms
3) Synthetic Aperture Radar (SAR)

## Science Requirements Lead to Observational Strategies

**Science Requirements Lead to Observational Strategies**

- Global Hyperspectral Imaging Radiometer
- Geostationary Hyperspectral Imaging Radiometer(s)
- Multi-Spectral High Spatial Resolution Imager
- Synthetic Aperture Radar (SAR)
- Sub-orbital Survey and Events UAV Suite
- Variable Fluorescence Lidar
- Mixed Layer Depth and Illumination Sensor
- Ocean Particle Profiler and Aerosol Column Distributions