MODIS-Aqua and SeaWiFS Ocean Color Timeseries ResultsMODIS-Aqua and SeaWiFS Ocean Color Timeseries ResultsShow Excellent Agreement After Latest ReprocessingShow Excellent Agreement After Latest Reprocessing

Bryan Franz, Code 614.2, NASA GSFCBryan Franz, Code 614.2, NASA GSFCThe spectral distribution of Water-leaving reflectance, Rrs(), is the fundamental quantity retrieved in ocean color remote sensing. This quantity can be used to derive information about the constituents of the water column, such as the concentration of the phytoplankton pigment chlorophyll-a. Following the latest multi-mission ocean color reprocessing, which involved nearly 2 years of effort to improve instrument calibrations, atmospheric correction algorithms, and bio-optical algorithms, MODIS-Aqua and SeaWiFS Rrs() and chlorophyll retrievals are now in excellent agreement over the common mission lifespans.

Figure 1: MODIS & SeaWIFS Water-leaving Reflectance

Hydrospheric and Biospheric Sciences Laboratory

Figure 2: MODIS & SeaWIFS Chlorophyll

Name: Bryan Franz, NASA/GSFC E-mail: bryan.a.franzd@nasa.govPhone: 301-286-5429

References:1.Ahmad, Z., B.A. Franz, C.R. McClain, E.J. Kwiatkowska, J. Werdell, E.P. Shettle, and B.N. Holben (2010). New aerosol models for the retrieval of aerosol optical thickness and normalized water-leaving radiances from the SeaWiFS and MODIS sensors over coastal regions and Open Oceans, Rem. Sens. Env, submitted.

2.Bailey, S.W., B.A. Franz, and P.J. Werdell (2010). Estimation of near-infrared water-leaving reflectance for satellite ocean color data processing, Opt. Exp., submitted.

3.Franz, B.A., S.W. Bailey, P.J. Werdell, and C.R. McClain, F.S. (2007). Sensor-Independent Approach to Vicarious Calibration of Satellite Ocean Color Radiometry, Appl. Opt., 46 (22).

4.Ahmad, Z., C.R. McClain, J.R. Herman, B.A. Franz, E.J. Kwiatkowska, W.D. Robinson, E.J. Buscela, and M. Tzortziou (2007). Atmospheric correction for NO2 absorption in retrieving water-leaving reflectances from SeaWiFS and MODIS measurements, Appl. Opt., 46 (22).

5.Franz, B.A., P.J. Werdell, G. Meister, S.W. Bailey, R.E. Eplee, G.C. Feldman, E. Kwiatkowska, C.R. McClain, F.S. Patt, D. Thomas (2005) . The continuity of ocean color measurements from SeaWiFS to MODIS, Proc. SPIE Earth Observing Systems X, San Diego, CA.

Data Sources: MODIS data from the Aqua EOS platform and SeaWiFS data from the Orview-2 spacecraft are collected, processed, and distributed by the Ocean Biology Processing Group at NASA/GSFC.

Technical Description of Image:Figure 1: Comparison of MODIS-Aqua and SeaWiFS remote-sensing reflectance (Rrs) time series for global deep-water (>1000m). Solid lines are SeaWiFS, dashed lines are MODIS. Colors indicate similar spectral bands (note light green is 510-nm SeaWiFS and 531-nm MODIS, so differences are expected).

Figure 2: Comparison of MODIS-Aqua and SeaWiFS chlorophyll-a time series for global deep-water (>1000m). Solid lines are SeaWiFS, dashed lines are MODIS.

Scientific significance: Satellite observations of the oceans provide the only practical means for measuring changes in the near-surface phytoplankton concentrations that is vital to modeling of marine primary production and the global carbon cycle. The establishment of consistency in measurements over common mission lifespans demonstrates that NASA can produce a long-term, continuous data record for this key climate variable by connecting past, present, and future missions.

Relevance for future science and relationship to Decadal Survey: These results demonstrate that a dedicated ocean color measurement team can produce consistent results from disparate sensors by emphasizing consistency in algorithms and calibration methods and focusing heavily on prelaunch and on-orbit instrument characterization. The same expertise and effort will be required to connect measurements from the SeaWiFS and MODIS era, through NPP/VIIRS, to the Decadal Survey's ACE mission.

Hydrospheric and Biospheric Sciences Laboratory

Placing Geoengineering and Other Climate Change Issues in the Broad Context of Earth History and Current State-of-the-Art Understandings

Claire L. Parkinson, Code 614.1, NASA GSFC

Hydrospheric and Biospheric Sciences Laboratory

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Early Earth

Feared future Earth

Current Earth

Ice-age Earth

Pangaea

Concerns about upcoming climate are leading some scientists to contemplate efforts to modify climate intentionally through geoengineering. There are many risks involved, including the possibility of causing considerable further damage, especially with intentional added emissions to the atmosphere or oceans or with placing reflective coverings over large regions.

Major relevant considerations include:-- The history of climate change on Earth illustrates repeatedly the

highly intertwined nature of many components of and processes affecting the Earth system (components: atmosphere, ocean, land, ice, life; processes: continental drift, volcanic eruptions, solar cycles, asteroid impacts, ozone depletion, etc.).

-- The paleoclimate record establishes that the Earth system is capable of much more abrupt changes than anything modern humans have experienced.

-- Humans have by now emerged as one of the many critical factors in global change and could conceivably precipitate an abrupt climate change, with or without geoengineering.

-- Our understandings are based on incomplete data and imperfect models. Global climate models are the best tools we have for predicting climate, but they have many limitations. A new book, Coming Climate Crisis? Consider the Past, Beware the Big Fix, details each of these topics, reflecting both the tremendous progress made in Earth system science in recent decades and the existence of significant remaining uncertainties.

Hydrospheric and Biospheric Sciences Laboratory

Name: Claire L. Parkinson, Code 614.1, NASA/GSFC E-mail: Claire.L.Parkinson@nasa.govPhone: 301-614-5715

Reference:Parkinson, C. L. (2010), Coming Climate Crisis? Consider the Past, Beware the Big Fix, Rowman & Littlefield Publishers, Lanham, Maryland, 411 pp.

Table of Contents of Coming Climate Crisis? Consider the Past, Beware the Big Fix: Part I. The Earth System and Its Ever-Changing Nature

1. Introduction2. 4.6 Billion Years of Global Change3. Abrupt Climate Change

Part II. The Human Factor4. A Short History of Human Impacts5. The Future: Why Some People Are So Concerned while Others Aren’t

Part III. Good Intentions and Geoengineering6. Good Intentions Gone Awry7. Geoengineering Schemes8. The Record on Smaller-Scale Attempted Modifications

Part IV. Further Cautionary Considerations9. The Possible Fallibility of Even a Strong Consensus10. The Unknown Future: Model Limitations11. Compounding Social Pressures

Part V. Avoiding Paralysis despite Uncertainty12. What Are the Alternatives?13. Closing Plea

Technical Description of Images: The five sequential globes shown on the accompanying slide represent schematically the vast changes that the Earth has undergone during its extended evolution, plus the feared future state. The first globe represents the early Earth, with an almost global ocean and no land masses as large as current continents. The second globe represents conditions hundreds of millions of years ago, with almost all the Earth’s land masses combined into one large continent called Pangaea. The third globe represents ice age conditions about 20,000 years ago. The fourth globe represents current conditions. The final globe represents an Earth on fire, for an embellished picture of the fears many have that global warming will lead to highly unpleasant conditions, for humans and other species.

Scientific significance: The Earth has been undergoing climate change for the past 4.6 billion years, always with an intertwining of many contributing factors. In the past few thousand years, especially the past 200 years, humans have emerged as one of the most important factors. Human impacts in the direction of increased global warming have led some people to consider counteracting those impacts through intentional large-scale climate modification called geoengineering. Because some of the proposed geoengineering schemes could have serious unintended consequences, it is critically important that we analyze carefully both the foundations of the climate predictions that are leading to the consideration of geoengineering and the possible unfavorable outcomes if indeed specific geoengineering schemes are implemented. The new book Coming Climate Crisis? Consider the Past, Beware the Big Fix tackles these difficult issues, including the limitations of global climate models, and lays the groundwork for further civil discussion.

Relevance for future science and relationship to Decadal Survey: Climate change discussions have become increasingly controversial and nasty in recent years, with many unfavorable consequences for science, including a diminished trust in scientists evidenced both by the general public and by policymakers. It is extremely important for future science that this unfortunate trend be reversed. The new book Coming Climate Crisis? Consider the Past, Beware the Big Fix attempts to help do that, by treating all sides in the climate controversy with respect and laying out the complicated reasons why there is room for very different but still legitimate attitudes toward upcoming climate change. The conclusions support the need for continued data collection and analysis, as planned by NASA through the Decadal Survey missions.

τ-ωmodel

L-band TB

L-band σo

Microwavedata

Vegetation morphology

Retrieved soil moisture

Tor Vergatamodel

emisveg

Development of combined passive/active microwave soil moisture retrieval algorithm

Alicia Joseph, Code 614.3, NASA GSFC

6/1/02 7/1/02 8/1/02 9/1/02 10/1/02

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Figure 1: Retrieval Method

Passive/active microwave retrieval algorithm is based on the Tor Vergata vegetation scattering model:

• L-band backscatter measurements are used to estimate the vegetation emissivity (emissveg);

• The emissveg in combination with L-band brightness temperature are used to retrieval soil moisture.

Hydrospheric and Biospheric Sciences Laboratory

Figure 2: Validation Plan: Validation of retrieval method using in-situ measurements and ground based radar/radiometer system, called ComRad.

Figure 3: First Results: B parameters, representative for emissveg, from simulated backscatter for a corn growth cycle.

Name: Alicia JosephE-mail: Alicia.T.Joseph@nasa.govPhone: (301) 614-5804

References:

Della Vecchia, A., P. Ferrazzoli, L. Guerriero, X. Blaes, P. Defourny, L. Dente, F. Mattia, G. Satalino, T. Strozzi, and U. Wegmuller, 2006: Influence of geometrical factors on crop backscattering at C-band. IEEE Transactions on Geoscience and remote sensing, 44, 778-790.

Bracaglia, M., P. Ferrazzoli, and L. Guerriero, 1995: A fully polarimetric multiple scattering model for crops. Remote Sensing of Environment, 54, 170-179.

Joseph, A.T., R.van der Velde, P.E. O’Neill, R.H. Lang, and T. Gish, 2008: Soil moisture retrieval during a corn growth cycle using L-band (1.6 GHz) radar observations. IEEE Transactions on Geoscience and remote sensing, 46, DOI: 10.1109/TGRS.2008.917214.

Joseph, A.T., R. van der Velde, P.E. O’Neill, B.J. Choudhury, R.H. Lang, E. Kim, and T.Gish: L band brightness temperature observations over a corn canopy during the entire growth cycle. submitted to SENSORS for publication. (In Press)

Data Sources: The proposed combined retrieval method is developed using the radar/radiometer observations collected during the following field campaigns: • Swiss Central Plains (Della Vecchia et al. 2006), crop type: corn; • Loamy site in the central part of Belgium (Della Vecchia et al. 2006), crop type: corn and wheat;• OPE3 site near Beltsville, Maryland (USA, Joseph et al. 2008), crop type: corn;• Italian Matera data set (Della Vecchia et al. 2006), crop type: wheat;

Technical Description of Image:

Figure 1: A schematization of how the proposed combined active/passive method could be implemented into a soil moisture retrieval algorithm.

Figure 2: Photographs of the combined radar/radiometer system, called ‘ComRad’, that will be used to provide measurements for calibration/validation of the proposed retrieval method, and illustration of vegetation morphological measurements that will be used for the algorithm development.

Figure 3: b-parameters, indicative for the vegetation emissivity, simulated by the Tor Vergata model for the OPE3 field campaign.

•Scientific significance: The advantage of proposed method is that the vegetation emissivity, affecting the brightness temperature (TB) measurements, is estimated from an independent data source using a physically based model, namely σo. As such, the inverted vegetation emissivities from the σo measurements would replace the usage of empirically determined parameters in global soil moisture retrieval algorithms. An additional advantage of using a physically based scattering model is that soil moisture retrieval uncertainties can be quantified. This level of confidence in soil moisture products is often needed for soil moisture assimilation into complex process modeling systems, such as numerical weather prediction models.

Relevance for future science and relationship to Decadal Survey: In the Decadal Survey, global soil moisture monitoring from space has been identified as an top priority because it will have applications within, for example, numerical weather prediction, drought monitoring and flood forecasting. Superior for retrieving soil moisture over a wide range of vegetated conditions are remote sensing observations collected by low frequency microwave instruments (<1.4 GHz). Currently, the NASA is in preparation for the launch of two missions carrying both passive and active L-band (~ 1.4 GHz) microwave sensors: Aquarius (expected launch in 2010) and Soil Moisture Active Passive (SMAP, expected launch in 2015).

Hydrospheric and Biospheric Sciences Laboratory