Physical and biogeochemical spatial scales of variability in the  East Australian Current separation from shelf glider measurements

Abstract. In contrast to physical processes, biogeochemical processes are inherently patchy in the ocean, which affects both the observational sampling strategy and the representativeness of sparse measurements in data assimilating models. In situ observations from multiple glider deployments are analysed to characterize spatial scales of variability in both physical and biogeochemical properties, using an empirical statistical model. We find that decorrelation ranges are strongly dependent on the balance between local dynamics and mesoscale forcing. The shortest horizontal (5–10 km) and vertical (45 m) decorrelation ranges are for chlorophyll a fluorescence, whereas those variables that are a function of regional ocean and atmosphere dynamics (temperature and dissolved oxygen) result in anisotropic patterns with longer ranges along (28–37 km) than across the shelf (8–19 km). Variables affected by coastal processes (salinity and coloured dissolved organic matter) have an isotropic range similar to the baroclinic Rossby radius (10–15 km).

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Physical and biogeochemical spatial scales of variability in the East Australian Current separation zone from shelf glider measurements

Biogeosciences Discussions ◽

10.5194/bgd-12-20101-2015 ◽

2015 ◽

Vol 12 (23) ◽

pp. 20101-20121 ◽

Cited By ~ 1

Author(s):

A. Schaeffer ◽

M. Roughan ◽

E. Jones ◽

D. White

Keyword(s):

Separation Zone ◽

Spatial Scales ◽

Sampling Strategy ◽

East Australian Current ◽

Biogeochemical Processes ◽

Colored Dissolved Organic Matter ◽

Physical Processes ◽

In Situ Observations ◽

Sparse Measurements

Abstract. In contrast to physical processes, biogeochemical processes are inherently patchy in the ocean, which affects both the observational sampling strategy and the representativeness of sparse measurements in data assimilating models. In situ observations from multiple glider deployments are analyzed to characterize spatial scales of variability in both physical and biogeochemical properties, using an empirical statistical model. We find that decorrelation ranges are strongly dependent on the balance between local dynamics and mesoscale forcing. The shortest horizontal (5–10 km) and vertical (45 m) decorrelation ranges are for chlorophyll $a$ fluorescence. Whereas those variables that are a function of regional ocean and atmosphere dynamics (temperature and dissolved oxygen) result in anisotropic patterns with longer ranges along (28–37 km) than across the shelf (8–19 km). Variables affected by coastal processes (salinity and colored dissolved organic matter) have an isotropic range similar to the baroclinic Rossby radius (10–15 km).

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Terrestrial aurora: astrophysical laboratory for anomalous abundances in stellar systems

Annales Geophysicae ◽

10.5194/angeo-32-77-2014 ◽

2014 ◽

Vol 32 (2) ◽

pp. 77-82 ◽

Cited By ~ 1

Author(s):

I. Roth

Keyword(s):

Solar Flares ◽

Heavy Ions ◽

Electromagnetic Waves ◽

Stellar System ◽

Decay Product ◽

Early Solar System ◽

Physical Processes ◽

In Situ Observations ◽

The Waves

Abstract. The unique magnetic structure of the terrestrial aurora as a conduit of information between the ionosphere and magnetosphere can be utilized as a laboratory for physical processes at similar magnetic configurations and applied to various evolutionary phases of the solar (stellar) system. The most spectacular heliospheric abundance enhancement involves the 3He isotope and selective heavy elements in impulsive solar flares. In situ observations of electromagnetic waves on active aurora are extrapolated to flaring corona in an analysis of solar acceleration processes of 3He, the only element that may resonate strongly with the waves, as well as heavy ions with specific charge-to-mass ratios, which may resonate weaker via their higher gyroharmonics. These results are applied to two observed anomalous astrophysical abundances: (1) enhanced abundance of 3He and possibly 13C in the late stellar evolutionary stages of planetary nebulae; and (2) enhanced abundance of the observed fossil element 26Mg in meteorites as a decay product of radioactive 26Al isotope due to interaction with the flare-energized 3He in the early solar system.

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Biogeochemistry and Climate

Biogeochemical Cycles and Climate ◽

10.1093/oso/9780198779308.003.0003 ◽

2019 ◽

pp. 29-43

Author(s):

Han Dolman

Keyword(s):

Ice Cores ◽

Atmospheric Composition ◽

System Modelling ◽

Biogeochemical Processes ◽

Sources And Sinks ◽

Direct Observations ◽

Geological Processes ◽

In Situ Observations ◽

Insight Into

This chapter focuses on tools for climate research: biogeochemical observations and models. It discusses physical climate observations, such as temperature and humidity, and in situ observations of atmospheric composition. Turning these into reliable climate records appears to be non-trivial. The chapter describes how isotopes are used to get insight into biogeochemical processes. A special category of observations is biogeochemical proxy observations, used to gain insight into geological processes when no direct observations are possible. The example of climate proxy observations, such as those obtained via ice cores, is described. Models are increasingly used to gain insight into sensitivity of climate to changes in the forcing. Earth system modelling has become increasingly complex over the last two decades, including often detailed biogeochemical processes in the ocean and on land. The parametrization of these remains an important research subject. Inverse modelling is being used to identify sources and sinks of greenhouse gases.

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In Situ Observations of the Occlusion of a Clay-Sugar Compound within Calcite

Environmental Science Nano ◽

10.1039/d1en00902h ◽

2022 ◽

Author(s):

Jialin Chi ◽

Chonghao Jia ◽

Wenjun Zhang ◽

Christine V Putnis ◽

Lijun Wang

Keyword(s):

Climate Change ◽

Organic Matter ◽

Soil Organic Matter ◽

Organic Carbon ◽

Global Climate Change ◽

Global Climate ◽

Ecological Systems ◽

In Situ Observations ◽

The Stability

The stability of soil organic matter (SOM) plays a key role in controlling global climate change as soil stores a large amount of organic carbon, compared with other ecological systems....

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Global In-Situ Observations of Essential Climate and Ocean Variables by the Global Drifter Program. Applications and Impacts

10.5194/egusphere-egu2020-20408 ◽

2020 ◽

Author(s):

Luca Centurioni ◽

Verena Hormann

Keyword(s):

North Atlantic Ocean ◽

Spatial Scales ◽

Data Access ◽

Ocean Climate ◽

The North ◽

Free Data ◽

Forecast Models ◽

In Situ Observations ◽

The Impact

<p>Accurate estimates and forecasts of physical and biogeochemical processes at the air-sea interface must rely on integrated in-situ and satellite surface observations of essential Ocean/Climate Variables (EOVs /ECVs). Such observations, when sustained over appropriate temporal and spatial scales, are particularly powerful in constraining and improving the skills, impact and value of weather, ocean and climate forecast models. The calibration and validation of satellite ocean products also rely on in-situ observations, thus creating further positive high-impact applications of observing systems designed for global sustained observations of EOV and ECVs.</p><p>The Global Drifter Program has operated uninterrupted for several decades and constitutes a particular successful example of a network of multiparametric platforms providing observations of climate, weather and oceanographic relevance (e.g. air-pressure, sea surface temperature, ocean currents). This presentation will review the requirements of sustainability of an observing system such as the GDP (i.e. cost effectiveness, peer-review of the observing methodology and of the technology, free data access and international cooperation), will present some key metrics recently used to quantify the impact of drifter observations, and will discuss two prominent examples of GDP regional observations and the transition to operations of novel platforms, such us wind and directional wave spectra drifters, in sparsely sampled regions of the Arabian Sea and of the North Atlantic Ocean.</p>

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Assessing Fluorescent Organic Matter in Natural Waters: Towards In Situ Excitation–Emission Matrix Spectroscopy

Applied Sciences ◽

10.3390/app8122685 ◽

2018 ◽

Vol 8 (12) ◽

pp. 2685 ◽

Cited By ~ 6

Author(s):

Oliver Zielinski ◽

Nick Rüssmeier ◽

Oliver Ferdinand ◽

Mario Miranda ◽

Jochen Wollschläger

Keyword(s):

Organic Matter ◽

Natural Waters ◽

Field Application ◽

Sensor System ◽

Biogeochemical Processes ◽

Good Correspondence ◽

Excitation Emission Matrix ◽

Fluorescent Dissolved Organic Matter ◽

Rapid Changes

Natural organic matter (NOM) is a key parameter in aquatic biogeochemical processes. Part of the NOM pool exhibits optical properties, namely absorption and fluorescence. The latter is frequently utilized in laboratory measurements of its dissolved fraction (fluorescent dissolved organic matter, FDOM) through excitation–emission matrix spectroscopy (EEMS). We present the design and field application of a novel EEMS sensor system applicable in situ, the ‘Kallemeter’. Observations are based on a field campaign, starting in Norwegian coastal waters entering the Trondheimsfjord. Comparison against the bulk fluorescence of two commercial FDOM sensors exhibited a good correspondence of the different methods and the ability to resolve gradients and dynamics along the transect. Complementary laboratory EEM spectra measurements of surface water samples and their subsequent PARAFAC analysis revealed three dominant components while the ‘Kallemeter’ EEMS sensor system was able to produce reasonable EEM spectra in high DOM concentrated water bodies, yet high noise levels must be addressed in order to provide comparable PARAFAC components. Achievements and limitations of this proof-of-concept are discussed providing guidance towards full in situ EEMS measurements to resolve rapid changes and processes in natural waters based on the assessment of spectral properties. Their combination with multiwavelength FDOM sensors onboard autonomous platforms will enhance our capacities in observing biogeochemical processes in the marine environment in spatiotemporal and spectral dimensions.

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On the Long-Wavelength Validation of the SWOT KaRIn Measurement

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-18-0148.1 ◽

2019 ◽

Vol 36 (5) ◽

pp. 843-848 ◽

Cited By ~ 4

Author(s):

Jinbo Wang ◽

Lee-Lueng Fu

Keyword(s):

Wavelength Range ◽

Spatial Scales ◽

Global Ocean ◽

Short Wavelength Range ◽

Long Wavelength ◽

Spatial Coverage ◽

In Situ Observations ◽

Wavenumber Spectrum ◽

Ocean Topography

AbstractThe Surface Water and Ocean Topography (SWOT) mission will measure the sea surface height (SSH) using a Ka-band radar interferometer (KaRIn) over a swath off the nadir of the satellite tracks. The mission requires calibration and validation (CalVal) of the SSH wavenumber spectrum at wavelengths between 15 and 1000 km. The CalVal in the short-wavelength range (15–150 km) requires in situ observations. In the long-wavelength range (150–1000 km), the CalVal will use the onboard Jason-class nadir altimeter. Using a high-resolution global ocean simulation, this study identifies the spatial scales beyond which the nadir and off-nadir observations can be considered comparable. Our results suggest that the ocean signals at nadir can represent off-nadir ocean signals at wavelengths longer than 120 and 70 km along the midswath and the inner edge of the KaRIn grid, respectively, indicating that the nadir altimeter is able to fulfill its goal to validate the long-wavelength KaRIn measurement. The wavelength along the inner edge is limited around 70 km because the onboard nadir altimeter cannot resolve spatial scales longer than ~70 km. These wavelengths provide a reference point for the required spatial coverage of the SWOT SSH in situ CalVal.

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In situ observations of soil minerals and organic matter in the early phases of prescribed fires

Journal of Geophysical Research Atmospheres ◽

10.1029/2011jd017420 ◽

2012 ◽

Vol 117 (D12) ◽

pp. n/a-n/a ◽

Cited By ~ 16

Author(s):

Ilias G. Kavouras ◽

George Nikolich ◽

Vic Etyemezian ◽

David W. DuBois ◽

James King ◽

...

Keyword(s):

Organic Matter ◽

Prescribed Fires ◽

Soil Minerals ◽

In Situ Observations ◽

Early Phases

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An Investigation of the Goshen County, Wyoming, Tornadic Supercell of 5 June 2009 Using EnKF Assimilation of Mobile Mesonet and Radar Observations Collected during VORTEX2. Part II: Mesocyclone-Scale Processes Affecting Tornado Formation, Maintenance, and Decay

Monthly Weather Review ◽

10.1175/mwr-d-15-0411.1 ◽

2016 ◽

Vol 144 (9) ◽

pp. 3441-3463 ◽

Cited By ~ 12

Author(s):

James Marquis ◽

Yvette Richardson ◽

Paul Markowski ◽

Joshua Wurman ◽

Karen Kosiba ◽

...

Keyword(s):

Life Cycle ◽

Ensemble Kalman Filter ◽

Vertical Structure ◽

Spatial Scales ◽

Near Surface ◽

Low Level ◽

Structure Changes ◽

In Situ Observations ◽

Negatively Buoyant

Storm-scale and mesocyclone-scale processes occurring contemporaneously with a tornado in the Goshen County, Wyoming, supercell observed on 5 June 2009 during the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) are examined using ensemble analyses produced by assimilating mobile radar and in situ observations into a high-resolution convection-resolving model. This paper focuses on understanding the evolution of the vertical structure of the storm, the outflow buoyancy, and processes affecting the vertical vorticity and circulation within the mesocyclone that correspond to changes in observed tornado intensity. Tornadogenesis occurs when the low-level mesocyclone is least negatively buoyant relative to the environment, possesses its largest circulation, and is collocated with the largest azimuthally averaged convergence during the analysis period. The average buoyancy, circulation, and convergence within the near-surface mesocyclone (on spatial scales resolved by the model) all decrease as the tornado intensifies and matures. The tornado and its parent low-level mesocyclone both dissipate surrounded by a weakening rear-flank downdraft. The decreasing buoyancy of parcels within the low-level mesocyclone may partly be responsible for the weakening of the updraft surrounding the tornado and decoupling of the mid- and low-level circulation. Although the supply of horizontal vorticity generated in the forward flank of the storm increases throughout the life cycle of the tornado, it is presumably less easily tilted and stretched on the mesocyclone-scale during tornado maturity owing to the disruption of the low-level updraft/downdraft structure. Changes in radar-measured tornado intensity lag those of ensemble Kalman filter (EnKF) mesocyclone vorticity and circulation.

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