Title page

“ Possible Geocape Capabilities Measurements of Diurnal Variability with Requirements of hours to days……………. “

Prezelin 1972

Diel Periodicity of Photosynthesis Variability

Prezelin 1972

Objectives

•Demonstrate experimental results of Diurnally bio-optical characteristics,

•Show cloud cover probability maps of different light intensities (PAR) in the GEOCAPE target area,

Pigment ratios which are affected by nutrients (e.g. eutrophication/pollution) can affect chlorophyll a fluorescence,

Demonstrate how chlorophyll a and FLH correlates in the GEOCAP target area (example: harmful algal bloom).

Chesapeake Light Tower

** Diurnal Cycle for One Year at the mouth of the Chesapeake Bay

LEO Probability of one clear pixel on a given day

GEO Probability of at least on clear pixel per day

The probability of obtaining acomplete time series over onesingle day of observing with aGEO satellite is about what isIs for obtaining a pixel on a givenday for a LEO satellite.

John R. Moisan

Comparison of GEO PAR and LEO PAR Products

Leo and Geo Derived PAR Products

John R. Moisan

Time Series along the COBY TransectIn the Mid Atlantic Bight (Moisan et al. 2010)

Conducted Diurnal Experiments

•Incubations begin at ~6 a.m. and sample for 12 hours every two hours

•Every hour around noon•Measurements include

• Fluorescence• Variable fluorescence• Estimate non-photochem.

quenching• Chl-specific absorption • HPLC pigments • Temperature • Light • Cell counts• Taxonomic composition• POC/PON

Diurnal Experiments of Phytoplankton Physiology

6 8 10 12 14 16 180

0.3

0.6

0.9

Fv/F

m

Exp4Exp595% CI

6 8 10 12 14 16 180

300

600

900

Fm

Exp4Exp595% CI

6 8 10 12 14 16 180

300

600

900

Time

Fo

Exp4Exp595% CI0.2

0.3

0.4

0.5

7 9 11 12 13 15 17 18

Time

Flu

ores

cenc

e

Experiment 4

Xanthophyll Cycling of Diatoxanthin and Diadinoxanthin: Changes in Chlorophyll a Fluorescence

Diel Periodicity varies with Different PFTs

(a) ERGB (b) Chl (c) FLH

A

B

MODIS/Aqua images on 21 January 2005MODIS/Aqua images on 21 January 2005Most of the band-ratio “Chl” is a false interpretation of CDOM and suspended Most of the band-ratio “Chl” is a false interpretation of CDOM and suspended sediments, but FLH is a more accurate indicator of biomass. In this case, the high sediments, but FLH is a more accurate indicator of biomass. In this case, the high FLH patch off Tampa Bay is a confirmed FLH patch off Tampa Bay is a confirmed Karenia brevisKarenia brevis bloom. bloom.

Courtesy of Dr, Chuanmin Hu

Questions and Conclusions

The temporal resolution of Geocape will support new physiological observations on unprecedented spatial scales

“linking short-time processes to remotely- sensed scales such as mixing, productivity (biophysical constraints), uptake etc.”

Defining diurnal responses with Geocape requirements will be a next challenge in understanding probabilities of cloud-freeskies

The temporal resolution will most likely lead to a more detaileddevelopment of satellite products as we merge spatial and temporal scales.

Observations of Diurnal Variability will increase the accuracy of estimates of Phytoplankton Physiology

-Including relative more low light observations will increase carbon estimates significantly;

-Inclusion of a diurnal signal will increase the accuracy of primary productivity, possible drawdown of pollution, and give status estimates of health (photoinhibition and pollution by eutrophication); and,

-Diurnal signals of productivity can vary seasonally with temperature, nutrients (eutrophication) and light (PAR, spectrally).

ATBD, Letelier et al.