In situ measurements for the cal/val of satellite …...In situ measurements for the cal/val of...

In situ measurements for the cal/val of satellite products

Aimee R. Neeley

NASA Ocean Ecology Laboratory

September 27, 2017

[email protected]

Aim of my talkWe use satellite ocean color(OC)-derived products to model phytoplankton biomass and types in aquatic systems.

• General ground-truthing

• In situ optical properties: Reflectances, absorption, backscatter and Chlorophyll a

• Filtration: Sampling for Chlorophyll a, etc.

• Phytoplankton: ‘measuring’ taxonomy

• Protocols and data archives

Algorithms and validation methods (ground-truthing!!) chosen could impact our interpretation of an ecosystem.

A. Neeley , NASA Ocean Ecology Laboratory, September 27, 2017 2

Ground-truthing OC

A. Neeley , NASA Ocean Ecology Laboratory, September 27, 20173

Radiometry

IOPs: backscatter, absorption, particle size distribution, chl

HPLC pigments & chlorophyll

Imaging and classical flow cytometry, microscopy

Courtesy of SeaDAS

Radiometric measurements

Above Water Optical Systems (e.g., Sea-Bird

HyperSAS)


AErosol RObotic NETwork

(AERONET)-OC

Radiometric Profilers

(e.g., Satlantic HyperPro)

https://aeronet.gsfc.nasa.gov

Inherent Optical Properties (IOPs)


Filtration: Measuring Chlorophyll a


Sample handling and precision

Protect samples from light!

Collect on 25mm glass fiber filters

Use low vacuum (<=5 mmHg)

Place in combusted foil packets

Store in Liquid Nitrogen then -80℃

Replicates⇢ at least 10-20% to

understand precision (or even better

samples in triplicate)

HPLC-measured Chlorophyll a• Quality assurance is implemented using a rigorous

QA/QC Plan document

• Internal standard ⇢ instrument precision

• SeaHARRE activities: established performance metrics

• Methodology: HPLC pigments, bacteriochlorophyll, phycobilins for cyanos (researching)

• Implementation (2019): Phycobilin pigment analysis

• Chl-a accuracy to within 6-7%


Technical manager:Crystal Thomas

[email protected]

Fluorometrically-measured Chlorophyll a

• Different methods/lamps: Welschmeyer vs Acidification Method (EPA method 445.0)

A. Neeley , NASA Ocean Ecology Laboratory, September 27, 2017 8Welschmeyer 1994 Limnol. Oceanogr.

Blue lamp (Optical Kit 10-040R)

White lamp (Optical Kit 10-037R)

Best when Chl b present Can determine Chl a and Pheophytin a

Acetone extraction only Acetone extraction and HCL


Fluorometrically-measured Chlorophyll a

Mean Absolute Error Acid method: 0.1276

Mean Absolute Error Welsch. method: 0.0811

**Preliminary data

Data courtesy of Crystal Thomas

Method 1: Microscopy and SEM

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Credit: Suncica Bosakand Zrinka Ljubesic

Method 2: FlowCAM


Credit: Stephanie Schollaert-Uz

Method 3: IFCB

12Credit: McClane

Method 4: Flow cytometry“Getting the little guys”


Count the number of particles and

autotrophic (fluorescing) organisms < 4

μm

Report size and identify these specific

groups (~0.5-2 μm, specifically; i.e.

Prochlorococcus, Synechococcus, pico-

eukaryotes).

The detection limit is important for

open ocean field work

Prochlorococcus (and other groups)

are dim at the surface; they can be

difficult to detect.

Online for public comment-June 2017

NASA/TM–2017–XXXX

The Particle Absorption Protocol

Aimee R. Neeley, Michael Towardowski, Rudiger Rottgers, Dariusz Stramski, Scott Freeman, Scott Pegau, Ronald Zaneveld,

James L. Mueller, Ed Fry, Emmanuel Boss, Collin Roesler, Eurico D’Sa, Rick Reynolds, Greg B. Mitchell

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The CDOM Protocol

Lead by Mike Novak and Antonio Mannino

Online for public comment, Fall 2017






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The Particle Absorption Protocol Beam-c Protocol

Lead by Aimee Neeley

FSG-Enabled Protocol Activities

Online for public comment-Fall 2017


The CDOM Protocol



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The Inline IOP Protocol

Lead by Emmanuel Boss






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The AOP Protocol Update

Lead by Giuseppe Zibordiand Ken Voss

The Particle Backscatter and VSF Protocol

Lead by Jim Sullivan and Wayne Slade






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Lead by Joaquin Chaves and Mike Novak

The Particulate Organic Carbon Protocol

Ongoing and In Development

**Future considerations (particle size, productivity, …)**14

Data quality review (of submitted data)

Field measurement intercomparisons/uncertainties (protocols)

Constrain (and improve our understanding of) uncertainties of

satellite-derived products

A platform from which we can develop regional and global

algorithms

Data archiving e.g., SeaBASS

Image courtesy of Chris Proctor


A. Neeley , NASA Ocean Ecology Laboratory, September 27, 2017 16https://seabass.gsfc.nasa.gov

Data archiving e.g., SeaBASS

In situ measurements for the cal/val of satellite …...In situ measurements for the cal/val of...

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