A Parallel SLA-Based Algorithm for Global Mesoscale Eddy Identification

AbstractThis paper proposes a new algorithm for parallel identification of mesoscale eddies from global satellite altimetry data. By simplifying the recognition process and the sea level anomaly (SLA) contours’ search range, the method improves identification efficiency compared with the previous SSH-based method even in the single-threaded process. The global SLA map is divided into several regions. These regions are identified simultaneously with a new SSH-based method. All the eddy identification results of these regions are merged seamlessly into a global eddy map. A β-plane approximation is used to calculate the geostrophic speed in the equatorial band. Compared with the computation complexity of the previous SSH-based method, which is , the computation complexity of the new method is , where K is the number of threads and L is the number of regional SLA maps. When applying the new method to the global SLA map, the computation is ~100 times faster than the previous SSH-based method on an average computer. The new method characterizes an eddy structure by radius, amplitude, eddy core, closed SLA contour, and closed SLA contour with maximum average geostrophic speed. In situ data and another global eddy dataset are applied to validate the reliability of eddies detected by the new algorithm. Global eddy mean properties, variability, and the geographical distribution of both datasets are analyzed to demonstrate the performance of this new method and to help understand eddy activities on a global scale.

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Extraction of Revolving Channels of Drifters around Mesoscale Eddy Centers Based on Spatiotemporal Trajectory Clustering

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-19-0007.1 ◽

2019 ◽

Vol 36 (9) ◽

pp. 1903-1916

Author(s):

Chunyong Ma ◽

Siqing Li ◽

Yang Yang ◽

Jie Yang ◽

Ge Chen

Keyword(s):

Clustering Algorithm ◽

Spatial Clustering ◽

Mesoscale Eddy ◽

Mesoscale Eddies ◽

Trajectory Clustering ◽

Satellite Altimeter ◽

Principal Mode ◽

In Situ Data ◽

Anticyclonic Eddies

The global oceanic transports of energy, plankton, and other tracers by mesoscale eddies can be estimated by combining satellite altimetry and in situ data. However, the revolving channels of particles entrained by mesoscale eddies, which could help explain the dynamic process of eddies entraining materials, are still unknown. In this study, satellite altimeter and drifter data from 1993 to 2016 are adopted, and the normalized trajectory clustering algorithm (N-TRACLUS) is proposed to extract the revolving channels of drifters. First, the trajectories of drifters are normalized and clustered by using the density-based spatial clustering of applications with noise (DBSCAN) algorithm. Next, the revolving channels of drifters around the eddy center are extracted. The ring or arc pattern in the middle of a normalized eddy appears when drifters are uninterruptedly entrained by eddies for more than 30 days. Moreover, the revolving channels of drifters in cyclonic eddies are relatively closer to the eddy center than those in anticyclonic eddies. These revolving channels suggest the principal mode of materials’ continuous motion processes that are inside eddies.

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Comparison of Multiple Surface Ocean Wind Products with Buoy Data over Blue Amazon (Brazilian Continental Margin)

Advances in Meteorology ◽

10.1155/2021/6680626 ◽

2021 ◽

Vol 2021 ◽

pp. 1-19

Author(s):

Vitor Paiva ◽

Milton Kampel ◽

Rosio Camayo

Keyword(s):

Wind Speed ◽

Continental Margin ◽

Surface Wind ◽

Remote Sensing Data ◽

Ocean Surface ◽

Surface Wind Speed ◽

Global Scale ◽

In Situ Data ◽

Ocean Surface Wind

Remote sensing data for space-time characterization of wind fields in extensive oceanic areas have been shown to be increasingly useful. Orbital sensors, such as radar scatterometers, provide data on ocean surface wind speed and direction with spatial and temporal resolutions suitable for multiple applications and air-sea studies. Even considering the relevant role of orbital scatterometers to estimate ocean surface wind vectors on a regional and global scale, the products must be validated regionally. Six different ocean surface wind datasets, including advanced scatterometer (ASCAT-A and ASCAT-B products) estimates, numerical modelling simulations (BRAMS), reanalysis (ERA5), and a blended product (CCMP), were compared statistically with in situ measurements obtained by anemometers installed in fifteen moored buoys in the Brazilian margin (8 buoys in oceanic and 7 in shelf waters) to analyze which dataset best represents the wind field in this region. The operational ASCAT wind products presented the lowest differences in wind speed and direction from the in situ data (0.77 ms−1 < RMSEspd < 1.59 ms−1, 0.75 < Rspd < 0.96, −0.68 ms−1 < biasspd < 0.38 ms−1, and 12.7° < RMSEdir < 46.8°). CCMP and ERA5 products also performed well in the statistical comparison with the in situ data (0.81 ms−1 < RMSEspd < 1.87 ms−1, 0.76 < Rspd < 0.91, −1.21 ms−1 < biasspd < 0.19 ms−1, and 13.7° < RMSEdir < 46.3°). The BRAMS model was the one with the worst performance (RMSEspd > 1.04 m·s−1, Rspd < 0.87). For regions with a higher wind variability, as in the southern Brazilian continental margin, wind direction estimation by the wind products is more susceptible to errors (RMSEdir > 42.4°). The results here presented can be used for climatological studies and for the estimation of the potential wind power generation in the Brazilian margin, especially considering the lack of availability or representativeness of regional data for this type of application.

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Appraising the capability of a land biosphere model as a tool in modelling land surface interactions: results from its validation at selected European ecosystems

Earth System Dynamics Discussions ◽

10.5194/esdd-6-217-2015 ◽

2015 ◽

Vol 6 (1) ◽

pp. 217-265 ◽

Cited By ~ 10

Author(s):

M. R. North ◽

G. P. Petropoulos ◽

G. Ireland ◽

J. P. McCalmont

Keyword(s):

Land Surface ◽

Model Performance ◽

Global Scale ◽

Surface Interactions ◽

Climatic Conditions ◽

Model Parameters ◽

Observation Data ◽

Ongoing Research ◽

In Situ Data

Abstract. In this present study the ability of the SimSphere Soil Vegetation Atmosphere Transfer (SVAT) model in estimating key parameters characterising land surface interactions was evaluated. Specifically, SimSphere's performance in predicting Net Radiation (Rnet), Latent Heat (LE), Sensible Heat (H) and Air Temperature (Tair) at 1.3 and 50 m was examined. Model simulations were validated by ground-based measurements of the corresponding parameters for a total of 70 days of the year 2011 from 7 CarboEurope network sites. These included a variety of biomes, environmental and climatic conditions in the models evaluation. Overall, model performance can largely be described as satisfactory for most of the experimental sites and evaluated parameters. For all model parameters compared, predicted H fluxes consistently obtained the highest agreement to the in-situ data in all ecosystems, with an average RMSD of 55.36 W m−2. LE fluxes and Rnet also agreed well with the in-situ data with RSMDs of 62.75 and 64.65 W m−2 respectively. A good agreement between modelled and measured LE and H fluxes was found, especially for smoothed daily flux trends. For both Tair 1.3 m and Tair 50 m a mean RMSD of 4.14 and 3.54 °C was reported respectively. This work presents the first all-inclusive evaluation of SimSphere, particularly so in a European setting. Results of this study contribute decisively towards obtaining a better understanding of the model's structure and its correspondence to the real world system. Findings also further establish the model's capability as a useful teaching and research tool in modelling Earth's land surface interactions. This is of considerable importance in the light of the rapidly expanding use of the model worldwide, including ongoing research by various Space Agencies examining its synergistic use with Earth Observation data towards the development of operational products at a global scale.

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In-Situ Measurements of Cirrus Clouds on a Global Scale

10.5194/egusphere-egu21-10885 ◽

2021 ◽

Author(s):

Gary Lloyd ◽

Thomas Choularton ◽

Martin Gallagher ◽

Martina kraemer ◽

Andreas Petzold ◽

...

Keyword(s):

Global Scale ◽

Cirrus Clouds ◽

Formation Mechanisms ◽

Commercial Aircraft ◽

Inter Tropical Convergence Zone ◽

Tropical Regions ◽

In Situ Data ◽

Cloud Properties ◽

Routine Monitoring

<div> Observations of high-altitude cirrus clouds are reported from measurements made during routine monitoring of cloud properties on commercial aircraft as part of In-Service Aircraft for a Global Observing System. The increasing global scale of the measurements is revealed, with 7 years of in-situ data producing a unique and rapidly growing dataset. We find cloud fractions measured >=10km at aircraft cruise altitude are representative of seasonal trends associated with the mid latitude jet stream in the northern hemisphere, and the relatively higher cloud fractions found in tropical regions such as the Inter-Tropical Convergence Zone and South East Asia. The characteristics of these clouds are discussed and the potential different formation mechanisms in different regions assessed. </div>

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In Situ Measurements of Cirrus Clouds on a Global Scale

Atmosphere ◽

10.3390/atmos12010041 ◽

2020 ◽

Vol 12 (1) ◽

pp. 41

Author(s):

Gary Lloyd ◽

Martin Gallagher ◽

Thomas Choularton ◽

Martina Krämer ◽

Petzold Andreas ◽

...

Keyword(s):

Global Scale ◽

Cirrus Clouds ◽

Formation Mechanisms ◽

Commercial Aircraft ◽

Inter Tropical Convergence Zone ◽

Tropical Regions ◽

In Situ Data ◽

Cloud Properties ◽

Routine Monitoring

Observations of high-altitude cirrus clouds are reported from measurements made during the routine monitoring of cloud properties on the commercial aircraft as part of the In-Service Aircraft for a Global Observing System. The increasing global scale of the measurements is revealed, with 7 years of in situ data producing a unique and rapidly growing dataset. We find that cloud fractions measured ≥ 10 km at aircraft cruise altitude are representative of seasonal trends associated with the mid-latitude jet stream in the Northern Hemisphere, and the relatively higher cloud fractions are found in tropical regions such as the Inter-Tropical Convergence Zone and South East Asia. Both stratospheric and tropospheric data were used to calculate the cloud fractions routinely experienced by commercial aircraft. Further work is needed for a direct comparison with previous studies that limit cloud fraction calculations to tropospheric data only. The characteristics of these clouds are discussed and the potential different formation mechanisms in different regions assessed.

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CMEMS Primary production from satellite remote sensing: spatial and temporal evolution and comparison with other products

10.5194/egusphere-egu2020-21903 ◽

2020 ◽

Author(s):

Marine Bretagnon ◽

Philippe Garnesson ◽

Antoine Mangin

Keyword(s):

Primary Production ◽

Carbon Sink ◽

Global Scale ◽

Trophic Levels ◽

Economic Resources ◽

In Situ Data ◽

Basin Scale ◽

Carbon Pump ◽

Satellite Estimate

Half of the global primary production is produced in the ocean by phytoplankton and the reaction of photosynthesis. For the marine environment, primary production is at the basis for the food web, by the supply of energy for higher trophic levels. Monitor primary production appears therefore to be a guideline to reach sustainable fisheries. In addition to its role on the trophic web, primary production is also important for its role on CO2 fluxes. Indeed, while phytoplankton creates matter from nutrients and CO2. The produced matter can be grazed by higher trophic levels or sink towards sediment. Amount of carbon sequestrated and exported out of the productive layer give some clues efficiencies of the oceanic biological carbon pump. Primary production is therefore important not only for economic resources, but also for climatic studies, to investigate if the ocean is a carbon sink or sources.A strategy of algorithm validation / inter-comparison was used as part as the CMEMS project to identify most accurate primary production algorithm among the most used in the literature.Primary production validation is based on the commonly used comparison with in situ data, as well as the frequency and the intensity of the annual bloom in different basin. Inter-comparison with model were performed at the basin scale of the Mediterranean Sea to assess the robustness and the consistency of different type of estimates.Satellite estimate of primary production, as proposed by CMEMS, give now access to an archive of 21 years for user community, to investigate evolution of primary production at the global scale or in specific basin.&#160;

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Geo-Analysis of Compatibility Determinants for Data in the Land and Property Register (LPR)

Geosciences ◽

10.3390/geosciences9070303 ◽

2019 ◽

Vol 9 (7) ◽

pp. 303 ◽

Cited By ~ 3

Author(s):

Katarzyna Kocur-Bera ◽

Marta Stachelek

Keyword(s):

Data Acquisition ◽

Natural Environment ◽

Global Scale ◽

Quality Data ◽

Main Role ◽

Investment Projects ◽

In Situ Data ◽

Land Administration ◽

Technical Potential

The development of modern technologies and accessibility of data on space and the natural environment has led to their increasing use for socio-economic purposes. Data users believe that these systems reflect the reality in the field. This applies in particular to databases used for construction investment projects or as the basis for calculations of financial obligations, e.g., taxes. The Land and Property Register (LPR), which is part of the Land Administration System, serves a number of economic and legal purposes. This geo-system often contains low-quality information regarding the technical potential of modern data acquisition methods and is continuously updated. The authors propose a two-step analysis of data contained in the LPR. The first step identified the sources of discrepancies between data from the LPR and the reality in the field. The second step emphasises the importance of the factors under analysis, which include both a plot’s geometric parameters, the geo-location features (associated with the natural environment elements) and factors associated with the supplementary data acquisition methods. The results show that sufficient quality data play the main role in achieving compatibility between the data in the Land and Property Register and with reality. Studies conducted so far have dealt with data on a global scale and were based on in situ data and focused on the specific values of each plot under analysis.

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The in situ Langendorff perfusion system: A new method for viral mediated gene transfer to porcine hearts prior transplantation

The Thoracic and Cardiovascular Surgeon ◽

10.1055/s-2008-1037868 ◽

2008 ◽

Vol 56 (S 1) ◽

Author(s):

L Burdorf ◽

N Schuhmann ◽

A Schulz ◽

M Köhn ◽

E Thein ◽

...

Keyword(s):

Gene Transfer ◽

New Method ◽

Perfusion System ◽

System A ◽

Langendorff Perfusion

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STORM ICE OIL WIND WAVE WATCH SYSTEM (SIOWS): WEB GIS APPLICATION FOR MONITORING THE ARCTIC

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b93852689d4.28131112 ◽

2017 ◽

Author(s):

Alexander Myasoedov ◽

Sergey Azarov ◽

Ekaterina Balashova ◽

...

Keyword(s):

Satellite Data ◽

Wind Wave ◽

Arctic Region ◽

Web Gis ◽

The Arctic ◽

Flexible Tool ◽

In Situ Data ◽

Current State ◽

Watch System

Working with satellite data, has long been an issue for users which has often prevented from a wider use of these data because of Volume, Access, Format and Data Combination. The purpose of the Storm Ice Oil Wind Wave Watch System (SIOWS) developed at Satellite Oceanography Laboratory (SOLab) is to solve the main issues encountered with satellite data and to provide users with a fast and flexible tool to select and extract data within massive archives that match exactly its needs or interest improving the efficiency of the monitoring system of geophysical conditions in the Arctic. SIOWS - is a Web GIS, designed to display various satellite, model and in situ data, it uses developed at SOLab storing, processing and visualization technologies for operational and archived data. It allows synergistic analysis of both historical data and monitoring of the current state and dynamics of the "ocean-atmosphere-cryosphere" system in the Arctic region, as well as Arctic system forecasting based on thermodynamic models with satellite data assimilation.

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