Effect of wind speed on aerosol optical depth over remote oceans, based on data from the Maritime Aerosol Network

The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. The MAN archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we investigate correlations between ship-borne aerosol optical depth (AOD) and near-surface wind speed, either measured (onboard or from satellite) or modeled (NCEP). According to our analysis, wind speed influences columnar aerosol optical depth, although the slope of the linear regression between AOD and wind speed is not steep (~0.004–0.005), even for strong winds over 10 m s−1. The relationships show significant scatter (correlation coefficients typically in the range 0.3–0.5); the majority of this scatter can be explained by the uncertainty on the input data. The various wind speed sources considered yield similar patterns. Results are in good agreement with the majority of previously published relationships between surface wind speed and ship-based or satellite-based AOD measurements. The basic relationships are similar for all the wind speed sources considered; however, the gradient of the relationship varies by around a factor of two depending on the wind data used

Effect of wind speed on aerosol optical depth over remote oceans, based on data from the Maritime Aerosol Network

The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. The MAN archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we investigate correlations between ship-borne aerosol optical depth (AOD) and near-surface wind speed, either measured (onboard or from satellite) or modeled (NCEP). According to our analysis, wind speed influences columnar aerosol optical depth, although the slope of the linear regression between AOD and wind speed is not steep (~0.004–0.005), even for strong winds over 10 m s<sup>−1</sup>. The relationships show significant scatter (correlation coefficients typically in the range 0.3–0.5); the majority of this scatter can be explained by the uncertainty on the input data. The various wind speed sources considered yield similar patterns. Results are in good agreement with the majority of previously published relationships between surface wind speed and ship-based or satellite-based AOD measurements. The basic relationships are similar for all the wind speed sources considered; however, the gradient of the relationship varies by around a factor of two depending on the wind data used

Maritime Aerosol Network as a Component of AERONET - First Results and Comparison with Global Aerosol Models and Satellite Retrievals

The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. Over 80 cruises were completed through early 2010 with deployments continuing. Measurement areas included various parts of the Atlantic Ocean, the Northern and Southern Pacific Ocean, the South Indian Ocean, the Southern Ocean, the Arctic Ocean and inland seas. MAN deploys Microtops handheld sunphotometers and utilizes a calibration procedure and data processing traceable to AERONET. Data collection included areas that previously had no aerosol optical depth (AOD) coverage at all, particularly vast areas of the Southern Ocean. The MAN data archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we present results of AOD measurements over the oceans, and make a comparison with satellite AOD retrievals and model simulations

Maïdo observatory: a new high-altitude station facility at Reunion Island (21° S, 55° E) for long-term atmospheric remote sensing and in situ measurements

Since the nineties, atmospheric measurement systems have been deployed at Reunion Island, mainly for monitoring the atmospheric composition in the framework of NDSC/NDACC (Network for the Detection of <i>Stratospheric</i> Change/Network for the Detection of Atmospheric Composition Change). The location of Reunion Island presents a great interest because there are very few multi-instrumented stations in the tropics and particularly in the southern hemisphere. In 2012, a new observatory was commissioned in Maïdo at 2200 m above sea level: it hosts various instruments for atmospheric measurements, including lidar systems, spectro-radiometers and in situ gas and aerosol measurements. <br><br> This new high-altitude Maïdo station provides an opportunity:<br> 1. to improve the performance of the optical instruments above the marine boundary layer, and to open new perspectives on upper troposphere and lower stratosphere studies;<br> 2. to develop in situ measurements of the atmospheric composition for climate change surveys, in a reference site in the tropical/subtropical region of the southern hemisphere;<br> 3. to offer trans-national access to host experiments or measurement campaigns for focused process studies

Evaluation of operational ocean forecasting systems from the perspective of the users and the experts

The Intergovernmental Oceanographic Commission (IOC) has an Ocean Decade Implementation Plan (UNESCO-IOC, 2021) that states seven outcomes required for the ocean we want, with the fourth outcome being “A predicted ocean where society understands and can respond to changing ocean conditions.” To facilitate the achievement of this goal, the IOC has endorsed Mercator Ocean International to implement the Decade Collaborative Center (DCC) for OceanPrediction (https://www.mercator-ocean.eu/oceanprediction/, last access: 21 August 2023), which is a cross-cutting structure that will work to develop global-scale collaboration between Decade Actions related to ocean prediction

Gene disruption and replacement as a feasible approach for mutagenesis of Campylobacter jejuni.

Campylobacter jejuni and Campylobacter coli are important causes of human enteric infections. Several determinants of pathogenicity have been proposed based on the clinical features of diarrheal disease and on the phenotypic properties of Campylobacter strains. To facilitate an understanding of the genetic determinants of Campylobacter virulence, we have developed a method for constructing C. jejuni mutants by shuttle mutagenesis. In the example described here, a kanamycin resistance gene was inserted into Campylobacter DNA fragments encoding 16S rRNA cloned in Escherichia coli. These disrupted, modified sequences were returned to C. jejuni via conjugation. Through the apparent process of homologous recombination, the kanamycin resistance-encoding sequences were rescued by chromosomal integration, resulting in the simultaneous gene replacement of one of the 16S sequences of C. jejuni and the loss of the vector. We propose that Campylobacter isogenic mutants could be developed by using this system of shuttle mutagenesis