SHOM cruise between Falmouth and Brest

The overall aim of the UKSOLAS project DOGEE-SOLAS is the parameterization of air-sea gas exchange, which is a currently a major uncertainty in global modelling. RRS Discovery cruise D320 thus was primarily concerned with the measurement of air-sea gas transfer velocities and some of the important physical parameters that influence them through contributing to near surface turbulence, and other processes. In brief, specific cruise objectives were: 1. Determine open ocean gas transfer velocities through a number of dual-tracer releases (3He & SF6). 2. Investigate the role of surfactant in gas exchange through a targeted surfactant release in conjunction with (1). 3. Determine CO2 fluxes and transfer velocities, and make associated hydrographic and turbulence related measurements from autonomous ASIS (Air-Sea Interaction Spar) buoys. 4. Measure air-sea fluxes of CO2, sensible heat, latent heat and momentum using the AUTOFLUX automated sensor array 5. Measure underway, total gas tension, dissolved O2, and CO2 to obtain independent air-sea gas exchange estimates. 6. Make covariance and gas budgeting estimates of air-sea gas exchange using intelligent profiling Lagrangian floats. 7. Independently determine DMS fluxes and gas transfer velocities for comparison with CO2 to examine the role of gas solubility in gas transfer. 8. Deploy a spar buoy (NOC) for measurement of wave heights and bubble properties 9. Record and measure whitecap coverage and wave breaking coincident with the air-sea flux measurements using ship mounted cameras 10. Record key meteorological variables 11. Quantify flow distortion biases in the direct flux measurements via the use of established models. 12. Make biogas, surfactant and bacterial measurements in the surface microlayer and in the uppermost metres of the ocean using surface microlayer samplers, a remotely operated catamaran, and a near surface sampler. 13. Deploy an autonomous powered profiler (ASIP) for turbulence-related measurements in the mixed layer. Objectives 1-12 were all met. Unfortunately, due to mechanical failure and loss of ASIP, objective 13 was not realised.

Objectives: To quantify marine halocarbon emission variability and latitudinal variation, characterise in situ open ocean atmospheric reactive iodine latitudinal variability and characterise oxidative chemistry perturbation due to oceanic emission of halogens from the Mauritanian upwelling region. Rationale: Transecting from the UK through Biscay, south past the west coast of Africa, through the Mauritanian upwelling, to pass Cape Verde simultaneous to the intensive deployment at the UK SOLAS Observatory on Sao Vicente, the measurements made on Discovery cruise D319 are intended to provide a detailed latitudinal characterisation of marine atmospheric halogen chemistry. This will feed validation and constraint data to regional and global models in projects linked to RHaMBLe. In addition the cruise will address a number of key scientific questions required to determine the global importance of iodine chemistry and to further our understanding of the controls of halogen chemistry in the remote ocean: i) How heterogeneous are the direct halogen sources and on what scale is the heterogeneity - does the upwelling region produce more or less halogens than the 'background' region? ii) What are the relative contributions of I atoms to the remote MBL from I2 and organic iodine? iii) Is sufficient iodine released to the remote MBL to sustain aerosol nucleation or to significantly affect the ozone budget and free radical populations? Measurement Description: Measured species included a variety of halocarbons in both water column and atmosphere and atmospheric boundary layer measurements of I2, OIO and IO by Broadband Cavity Enhanced Absorption Spectroscopy (BBCEAS). A compact version of the FAGE system, developed for the FAAM BAe-146, was deployed to provide measurements of IO or OH / HO2, permitting direct assessment of RHS-induced changes in the oxidising environment through the upwelling region. A range of trace gas monitors was simultaneously deployed to measure O3 and NOx. Aerosol number and size distribution measurements from 3 nm to 20 micron diameter were also made by a range of mobility (SMPS) and optical instrumentation, (OPC and FSSP). Additional aerosol measurements were provided as part of the NERC-funded ACMME project (PI Allan). Measurements of pigments in the surface waters were made by HPLC. Prevailing meteorological conditions were used to direct the cruise in terms of geographical positioning and measurement interpretation, e.g. i) exploitation of any broad flow connection between Cape Verde and the ship to interpret measurements as process studies and ii) identification of in- and out-of-plume conditions to contrast chemistry influenced and uninfluenced by emissions from the upwelling region.

The objective of the cruise was to improve our understanding of biochemical processes in the near-surface and microlayer of the ocean. We examine gradients in major nutrient concentrations and cycling, production and consumption of key biogases and variability in biological communities between micro-layer, near -surface and deeper water, and between productive and oligotrophic waters along a transect from offshore oligotrophic to coastal upwelling waters off western Spain and Portugal. We also aimed to examine the influence of gradients in physical, biological and photochemical processes at or near the surface micro-layer on the transport of heat and bio-gases across the air-sea interface. Using near-real time satellite imagery of ocean colour in combination with continuous underway measurements of sea surface temperature and chlorophyll fluorescence we identified a suitable oligotrophic site ~25nm off the coast just north of the spain/Portugal border, and reached it on 21 st June and commenced scientific work. We then worked our way inshore via 4 more stations to an upwelling site where science work was concluded on 6th July. The vessel then returned to Falmouth, arriving on 9th July.

The SCANS-II project aims at estimating the abundance of small cetaceans inhabiting shelf waters of the Atlantic margin, the North Sea and adjacent waters. Different methods will be used; ship-based monitoring is one of these. Data on abundance are essential to assess the impact of bycatch and other threats, and as input to management actions to ensure the favourable conservation status of these species. The project will develop a management framework to use such data. This will be centred on relatively simple but spatially explicit dynamic models tested by simulation to ensure robustness. An essential part of this long-term management is a robust cost-effective means of monitoring abundance between major SCANS-type surveys; the project will develop and test potential methods, and recommend a suite of monitoring protocols.The "BEL-COLOUR" aims at improving the theoretical basis and software tools for applications of suspended matter and chlorophyll-based satellite data products in coastal waters. In addition to algorithm work and image processing BEL-COLOUR will participate in sea borne cruises for the purposes of calibration of algorithms and for validation of the end products. The project "BEL-COLOUR", funded by the <a href="http://www.belspo.be">Federal Science Policy</a>, within the programme for Earth Observation "STEREO" - Study and management of Coastal Regions.