Reviews and Syntheses: Flying the Satellite into Your Model

Mapping Intimacies ◽

10.5194/bg-2016-237 ◽

2016 ◽

Cited By ~ 1

Author(s):

Thomas Kaminski ◽

Pierre-Philippe Mathieu

Keyword(s):

Data Assimilation ◽

Automatic Differentiation ◽

Satellite Observations ◽

Spectral Radiance ◽

Earth System ◽

The Earth ◽

Retrieval Scheme ◽

Research Tools

Abstract. The vehicles that fly the satellite into a model of the Earth System are observation operators. They provide the link between the quantities simulated by the model and quantities observed from space, either directly (spectral radiance) or indirectly estimated through a retrieval scheme (bio-geophysical variables). By doing so, observation operators enable modellers to properly compare, evaluate and constrain their models with the model-analogue of the satellite observations. This paper provides the formalism and a few examples of how observation operators can be used, in combination with data assimilation techniques, to better ingest satellite products in a manner consistent with the dynamics of the Earth System expressed by models. It describes communalities and potential synergies between assimilation and classical retrievals. The paper explains how the combination of observation operators and their derivatives (linearisations) form powerful research tools. It introduces a technique called automatic differentiation that greatly simplifies both development and maintenance of derivative code.

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Reviews and syntheses: Flying the satellite into your model: on the role of observation operators in constraining models of the Earth system and the carbon cycle

Biogeosciences ◽

10.5194/bg-14-2343-2017 ◽

2017 ◽

Vol 14 (9) ◽

pp. 2343-2357 ◽

Cited By ~ 16

Author(s):

Thomas Kaminski ◽

Pierre-Philippe Mathieu

Keyword(s):

Data Assimilation ◽

Carbon Cycle ◽

Automatic Differentiation ◽

Satellite Observations ◽

Spectral Radiance ◽

Special Focus ◽

Earth System ◽

The Earth ◽

Retrieval Scheme

Abstract. The vehicles that fly the satellite into a model of the Earth system are observation operators. They provide the link between the quantities simulated by the model and the quantities observed from space, either directly (spectral radiance) or indirectly estimated through a retrieval scheme (biogeophysical variables). By doing so, observation operators enable modellers to properly compare, evaluate, and constrain their models with the model analogue of the satellite observations. This paper provides the formalism and a few examples of how observation operators can be used in combination with data assimilation techniques to better ingest satellite products in a manner consistent with the dynamics of the Earth system expressed by models. It describes commonalities and potential synergies between assimilation and classical retrievals. This paper explains how the combination of observation operators and their derivatives (linearizations) form powerful research tools. It introduces a technique called automatic differentiation that greatly simplifies both the development and the maintenance of code for the evaluation of derivatives. Throughout this paper, a special focus lies on applications to the carbon cycle.

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Geosystemics View of Earthquakes

Entropy ◽

10.3390/e21040412 ◽

2019 ◽

Vol 21 (4) ◽

pp. 412 ◽

Cited By ~ 6

Author(s):

Angelo De Santis ◽

Cristoforo Abbattista ◽

Lucilla Alfonsi ◽

Leonardo Amoruso ◽

Saioa A. Campuzano ◽

...

Keyword(s):

Solid Earth ◽

Point Of View ◽

Satellite Observations ◽

Earth System ◽

Seismic Sequences ◽

The Earth ◽

Earth’S Interior ◽

Earth's Interior ◽

Physical Quantities

Earthquakes are the most energetic phenomena in the lithosphere: their study and comprehension are greatly worth doing because of the obvious importance for society. Geosystemics intends to study the Earth system as a whole, looking at the possible couplings among the different geo-layers, i.e., from the earth’s interior to the above atmosphere. It uses specific universal tools to integrate different methods that can be applied to multi-parameter data, often taken on different platforms (e.g., ground, marine or satellite observations). Its main objective is to understand the particular phenomenon of interest from a holistic point of view. Central is the use of entropy, together with other physical quantities that will be introduced case by case. In this paper, we will deal with earthquakes, as final part of a long-term chain of processes involving, not only the interaction between different components of the Earth’s interior but also the coupling of the solid earth with the above neutral or ionized atmosphere, and finally culminating with the main rupture along the fault of concern. Particular emphasis will be given to some Italian seismic sequences.

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Geosystemics View of Earthquakes

10.5194/egusphere-egu2020-22588 ◽

2020 ◽

Author(s):

Gianfranco Cianchini ◽

Keyword(s):

Solid Earth ◽

Point Of View ◽

Satellite Observations ◽

Final Part ◽

Earth System ◽

Seismic Sequences ◽

The Earth ◽

Physical Quantities

<p>Earthquakes, the most energetic phenomena in the lithosphere, often cause danger and casualties: thus, their study and comprehension are greatly worth doing because of the obvious importance for society. Geosystemics intends to offer a way to study the Earth system by viewing it as a whole, looking at the possible couplings among the different geo-layers, i.e., from the earth&#8217;s interior up to the ionosphere through the atmosphere. It uses specific universal tools to integrate different methods that can be applied to multi-parameter data, often taken on different platforms (e.g., ground, marine or satellite observations). Its main aim is to understand the particular phenomenon of interest from a holistic point of view. Central is the use of entropy, together with other physical quantities that are introduced case by case. In this paper, we will deal with earthquakes, as final part of a long-term chain of processes involving, not only the interaction between different components of the Earth&#8217;s interior but also the coupling of the solid earth with the above neutral or ionized atmosphere, and finally culminating with the main rupture along the fault of concern. Particular emphasis will be given to some Italian seismic sequences.</p>

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An Evaluation of Antarctic Sea Ice Thickness from the Global Ice-Ocean Modeling and Assimilation System based on In-situ and Satellite Observations

10.5194/tc-2021-228 ◽

2021 ◽

Author(s):

Sutao Liao ◽

Hao Luo ◽

Jinfei Wang ◽

Qian Shi ◽

Jinlun Zhang ◽

...

Keyword(s):

Sea Ice ◽

Satellite Observations ◽

Ocean Modeling ◽

Ice Thickness ◽

Earth System ◽

Sea Ice Thickness ◽

Antarctic Sea Ice ◽

The Earth ◽

Assimilation System

Abstract. Antarctic sea ice is an important component of the Earth system. However, its role in the Earth system is still not very clear due to limited Antarctic sea ice thickness (SIT) data. A reliable sea ice reanalysis can be useful to study Antarctic SIT and its role in the Earth system. Among various Antarctic sea ice reanalysis products, the Global Ice-Ocean Modeling and Assimilation System (GIOMAS) output is widely used in the research of Antarctic sea ice. As more Antarctic SIT observations with quality control are released, a further evaluation of Antarctic SIT from GIOMAS is conducted in this study based on in-situ and satellite observations. Generally, though only sea ice concentration is assimilated, GIOMAS can basically reproduce the observed variability of sea ice volume and its changes in the trend before and after 2013, indicating that GIOMAS is a good option to study the long-term variation of Antarctic sea ice. However, due to deficiencies in model and asymmetric changes in SIT caused by assimilation, GIOMAS underestimates Antarctic SIT especially in deformed ice regions, which has an impact on not only the mean state of SIT but also the variability. Thus, besides the further development of model, assimilating additional sea ice observations (e.g., SIT and sea ice drift) with advanced assimilation methods may be conducive to a more accurate estimation of Antarctic SIT.

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