Real-Time In Situ Observations Reveal a Double Role for Ascorbic Acid in the Anisotropic Growth of Silver on Gold

Timely processing of observations from multi-spectral imagers, such as SEVIRI (Spinning Enhanced Visible and Infrared Imager), largely depends on fast radiative transfer calculations. This paper mostly concerns the development and implementation of a new forward model for SEVIRI to be applied to real time processing of infrared radiances. The new radiative transfer model improves computational time by a factor of ≈7 compared to the previous versions and makes it possible to process SEVIRI data at nearly real time. The new forward model has been applied for the retrieval of surface parameters. Although the scheme can be applied for the simultaneous retrieval of temperature and emissivity, the paper mostly focuses on emissivity. The inverse scheme relies on a Kalman filter approach, which allows us to exploit a sequential processing of SEVIRI observations. Based on the new forward model, the paper also presents a validation retrieval performed with in situ observations acquired during a field experiment carried out in 2017 at Gobabeb (Namib desert) validation station. Furthermore, a comparison with IASI (Infrared Atmospheric Sounder Interferometer) emissivity retrievals has been performed as well. It has been found that the retrieved emissivities are in good agreement with each other and with in situ observations, i.e., average differences are generally well below 0.01.

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The Lightning and Dual-Polarization Radar Characteristics of Three Hail-Accumulating Thunderstorms

Weather and Forecasting ◽

10.1175/waf-d-19-0224.1 ◽

2020 ◽

Vol 35 (4) ◽

pp. 1583-1603

Author(s):

Robinson Wallace ◽

Katja Friedrich ◽

Wiebke Deierling ◽

Evan A. Kalina ◽

Paul Schlatter

Keyword(s):

Real Time ◽

Scientific Community ◽

Radar Data ◽

Optimal Combination ◽

Front Range ◽

Dual Polarization ◽

Translation Speed ◽

Maximum Accumulation ◽

In Situ Observations

AbstractThunderstorms that produce hail accumulations at the surface can impact residents by obstructing roadways, closing airports, and causing localized flooding from hail-clogged drainages. These storms have recently gained an increased interest within the scientific community. However, differences that are observable in real time between these storms and storms that produce nonimpactful hail accumulations have yet to be documented. Similarly, the characteristics within a single storm that are useful to quantify or predict hail accumulations are not fully understood. This study uses lightning and dual-polarization radar data to characterize hail accumulations from three storms that occurred on the same day along the Colorado–Wyoming Front Range. Each storm’s characteristics are verified against radar-derived hail accumulation maps and in situ observations. The storms differed in maximum accumulation, either producing 22 cm, 7 cm, or no accumulation. The magnitude of surface hail accumulations is found to be dependent on a combination of in-cloud hail production, storm translation speed, and hailstone melting. The optimal combination for substantial hail accumulations is enhanced in-cloud hail production, slow storm speed, and limited hailstone melting. However, during periods of similar in-cloud hail production, lesser accumulations are derived when storm speed and/or hailstone melting, identified by radar presentation, is sufficiently large. These results will aid forecasters in identifying when hail accumulations are occurring in real time.

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Synoptic Estimates of Waves and Currents via Real-Time Assimilation of In-Situ Observations

10.21236/ada628151 ◽

2002 ◽

Author(s):

David T. Walker ◽

Merrick C. Haller

Keyword(s):

Real Time ◽

Waves And Currents ◽

In Situ Observations

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Real-time in situ observations of reaction and transport phenomena during silicate glass corrosion by fluid-cell Raman spectroscopy

Nature Materials ◽

10.1038/s41563-019-0293-8 ◽

2019 ◽

Vol 18 (4) ◽

pp. 342-348 ◽

Cited By ~ 19

Author(s):

Thorsten Geisler ◽

Lars Dohmen ◽

Christoph Lenting ◽

Moritz B. K. Fritzsche

Keyword(s):

Raman Spectroscopy ◽

Real Time ◽

Silicate Glass ◽

Transport Phenomena ◽

Glass Corrosion ◽

In Situ Observations ◽

Fluid Cell

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From satellite altimetry to Argo and operational oceanography: three revolutions in oceanography

Ocean Science Discussions ◽

10.5194/osd-10-1127-2013 ◽

2013 ◽

Vol 10 (4) ◽

pp. 1127-1167 ◽

Cited By ~ 3

Author(s):

P. Y. Le Traon

Keyword(s):

High Resolution ◽

Real Time ◽

Sea Level ◽

Ocean Circulation ◽

Satellite Altimetry ◽

Large Scale ◽

Global Ocean ◽

Operational Oceanography ◽

In Situ Observations

Abstract. The launch of the US/French mission Topex/Poseidon (T/P) (CNES/NASA) in August 1992 was the start of a revolution in oceanography. For the first time, a very precise altimeter system optimized for large scale sea level and ocean circulation observations was flying. T/P alone could not observe the mesoscale circulation. In the 1990s, the ESA satellites ERS-1/2 were flying simultaneously with T/P. Together with my CLS colleagues, we demonstrated that we could use T/P as a reference mission for ERS-1/2 and bring the ERS-1/2 data to an accuracy level comparable to T/P. Near real time high resolution global sea level anomaly maps were then derived. These maps have been operationally produced as part of the SSALTO/DUACS system for the last 15 yr. They are now widely used by the oceanographic community and have contributed to a much better understanding and recognition of the role and importance of mesoscale dynamics. Altimetry needs to be complemented with global in situ observations. In the end of the 90s, a major international initiative was launched to develop Argo, the global array of profiling floats. This has been an outstanding success. Argo floats now provide the most important in situ observations to monitor and understand the role of the ocean on the earth climate and for operational oceanography. This is a second revolution in oceanography. The unique capability of satellite altimetry to observe the global ocean in near real time at high resolution and the development of Argo were essential to the development of global operational oceanography, the third revolution in oceanography. The Global Ocean Data Assimilation Experiment (GODAE) was instrumental in the development of the required capabilities. This paper provides an historical perspective on the development of these three revolutions in oceanography which are very much interlinked. This is not an exhaustive review and I will mainly focus on the contributions we made together with many colleagues and friends.

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Assimilating GlobColour ocean colour data into a pre-operational physical-biogeochemical model

Ocean Science Discussions ◽

10.5194/osd-9-687-2012 ◽

2012 ◽

Vol 9 (2) ◽

pp. 687-744 ◽

Cited By ~ 5

Author(s):

D. A. Ford ◽

K. P. Edwards ◽

D. Lea ◽

R. M. Barciela ◽

M. J. Martin ◽

...

Keyword(s):

Real Time ◽

Chlorophyll Concentration ◽

Ocean Basin ◽

Biogeochemical Model ◽

State Variables ◽

Ocean Colour ◽

In Situ Observations ◽

Time Basis ◽

The Impact

Abstract. As part of the GlobColour project, daily chlorophyll-a observations, derived using remotely sensed ocean colour data from the MERIS, MODIS and SeaWiFS sensors, are produced. The ability of these products to be assimilated into a pre-operational global coupled physical-biogeochemical model has been tested, on both a hindcast and near-real-time basis, and the impact on the system assessed. The assimilation was found to immediately and significantly improve the bias, root mean square error and correlation of modelled surface chlorophyll concentration compared to the GlobColour observations, an improvement which was sustained throughout the year and in every ocean basin. Errors against independent in situ chlorophyll observations were also reduced, both at and beneath the ocean surface. However the model fit to in situ observations was not consistently better than that of climatology, due to errors in the underlying model. The assimilation scheme used is multivariate, updating all biogeochemical model state variables at all depths. Consistent changes were found in the other model variables, with reduced errors against in situ observations of nitrate and pCO2, and evidence of improved representation of zooplankton concentration. Annual mean surface fields of nutrients, alkalinity and carbon variables remained of similar quality compared to climatology. The near-real-time GlobColour products were found to be sufficiently reliable for operational purposes, and of benefit to both operational-style systems and reanalyses.

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SEVIRI Hyper-Fast Forward Model with Application to Emissivity Retrieval

10.20944/preprints201903.0018.v1 ◽

2019 ◽

Author(s):

Guido Masiello ◽

Carmine Serio ◽

Sara Venafra ◽

Laurent Poutier ◽

Frank-M. Göttsche

Keyword(s):

Radiative Transfer ◽

Surface Temperature ◽

Real Time ◽

Forward Model ◽

Radiative Transfer Model ◽

Computational Time ◽

Transfer Model ◽

Real Time Processing ◽

In Situ Observations

Timely processing of observations from hyper-spectral imagers, such as SEVIRI (Spinning Enhanced Visible and Infrared Imager), largely depends on fast radiative transfer calculations. This paper mostly concerns the development and implementation of a new forward model for SEVIRI to be applied to real time processing of infrared radiances for the physical retrieval of surface temperature and emissivity. The new radiative transfer model improves computational time by a factor of ≈ 7 compared to the previous versions and makes it possible to process SEVIRI data at nearly real time. The new forward model has been applied for the simultaneous retrieval of surface temperature and emissivity in three infrared channels (8.7, 10.8, 12 μm). The inverse scheme relies on a Kalman filter approach, which allows us to exploit a sequential processing of SEVIRI observations. Based on the new forward model, the paper also presents a validation retrieval performed with in situ observations acquired during a field experiment carried out in 2017 at Gobabeb (Namib desert) validation station. Furthermore, a comparison with IASI (Infrared Atmospheric Sounder Interferometer) emissivity retrievals has been performed as well. It has been found that the retrieved emissivities are in good agreement with each other and with in situ observations, i.e. average differences are generally well below 0.01.

Download Full-text

Synoptic Estimates of Waves and Currents via Real-Time Assimilation of In-Situ Observations

10.21236/ada612990 ◽

2004 ◽

Author(s):

Merrick C. Haller

Keyword(s):

Real Time ◽

Waves And Currents ◽

In Situ Observations

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From satellite altimetry to Argo and operational oceanography: three revolutions in oceanography

Ocean Science ◽

10.5194/os-9-901-2013 ◽

2013 ◽

Vol 9 (5) ◽

pp. 901-915 ◽

Cited By ~ 43

Author(s):

P. Y. Le Traon

Keyword(s):

High Resolution ◽

Real Time ◽

Sea Level ◽

Ocean Circulation ◽

Satellite Altimetry ◽

Large Scale ◽

Global Ocean ◽

Operational Oceanography ◽

In Situ Observations

Abstract. The launch of the French/US mission Topex/Poseidon (T/P) (CNES/NASA) in August 1992 was the start of a revolution in oceanography. For the first time, a very precise altimeter system optimized for large-scale sea level and ocean circulation observations was flying. T/P alone could not observe the mesoscale circulation. In the 1990s, the ESA satellites ERS-1/2 were flying simultaneously with T/P. Together with my CLS colleagues, we demonstrated that we could use T/P as a reference mission for ERS-1/2 and bring the ERS-1/2 data to an accuracy level comparable to T/P. Near-real-time high-resolution global sea level anomaly maps were then derived. These maps have been operationally produced as part of the SSALTO/DUACS system for the last 15 yr. They are now widely used by the oceanographic community and have contributed to a much better understanding and recognition of the role and importance of mesoscale dynamics. Altimetry needs to be complemented with global in situ observations. At the end of the 90s, a major international initiative was launched to develop Argo, the global array of profiling floats. This has been an outstanding success. Argo floats now provide the most important in situ observations to monitor and understand the role of the ocean on the earth climate and for operational oceanography. This is a second revolution in oceanography. The unique capability of satellite altimetry to observe the global ocean in near-real-time at high resolution and the development of Argo were essential for the development of global operational oceanography, the third revolution in oceanography. The Global Ocean Data Assimilation Experiment (GODAE) was instrumental in the development of the required capabilities. This paper provides an historical perspective on the development of these three revolutions in oceanography which are very much interlinked. This is not an exhaustive review and I will mainly focus on the contributions we made together with many colleagues and friends.

Download Full-text