Coordinated airborne studies in the tropics (CAST)

This is the final version of the article. It first appeared from the American Meteorological Society via http://dx.doi.org/10.1175/BAMS-D-14-00290.1Abstract The main field activities of the Coordinated Airborne Studies in the Tropics (CAST) campaign took place in the west Pacific during January–February 2014. The field campaign was based in Guam (13.5°N, 144.8°E), using the U.K. Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 atmospheric research aircraft, and was coordinated with the Airborne Tropical Tropopause Experiment (ATTREX) project with an unmanned Global Hawk and the Convective Transport of Active Species in the Tropics (CONTRAST) campaign with a Gulfstream V aircraft. Together, the three aircraft were able to make detailed measurements of atmospheric structure and composition from the ocean surface to 20 km. These measurements are providing new information about the processes influencing halogen and ozone levels in the tropical west Pacific, as well as the importance of trace-gas transport in convection for the upper troposphere and stratosphere. The FAAM aircraft made a total of 25 flights in the region between 1°S and 14°N and 130° and 155°E. It was used to sample at altitudes below 8 km, with much of the time spent in the marine boundary layer. It measured a range of chemical species and sampled extensively within the region of main inflow into the strong west Pacific convection. The CAST team also made ground-based measurements of a number of species (including daily ozonesondes) at the Atmospheric Radiation Measurement Program site on Manus Island, Papua New Guinea (2.1°S, 147.4°E). This article presents an overview of the CAST project, focusing on the design and operation of the west Pacific experiment. It additionally discusses some new developments in CAST, including flights of new instruments on board the Global Hawk in February–March 2015.CAST is funded by NERC and STFC, with grant NE/ I030054/1 (lead award), NE/J006262/1, NE/J006238/1, NE/J006181/1, NE/J006211/1, NE/J006061/1, NE/J006157/1, NE/J006203/1, NE/J00619X/1, and NE/J006173/1. N. R. P. Harris was supported by a NERC Advanced Research Fellowship (NE/G014655/1). P. I. Palmer acknowledges his Royal Society Wolfson Research Merit Award. The BAe-146-301 Atmospheric Research Aircraft is flown by Directflight Ltd and managed by the Facility for Airborne Atmospheric Measurements, which is a joint entity of the Natural Environment Research Council and the Met Office. The authors thank the staff at FAAM, Directflight and Avalon Aero who worked so hard toward the success of the aircraft deployment in Guam, especially for their untiring efforts when spending an unforeseen 9 days in Chuuk. We thank the local staff at Chuuk and Palau, as well as the authorities in the Federated States of Micronesia for their help in facilitating our research flights. Special thanks go to the personnel associated with the ARM facility at Manus, Papua New Guinea without whose help the ground-based measurements would not have been possible. Thanks to the British Atmospheric Data Centre (BADC) for hosting our data and the NCAS Atmospheric Measurement Facility for providing the radiosonde and ground-based ozone equipment. Chlorophyll-a data used in Figure 1 were extracted using the Giovanni online data system, maintained by the NASA GES DISC. We acknowledge the MODIS mission scientists and associated NASA personnel for the production of this data set. Finally we thank many individuals associated with the ATTREX and CONTRAST campaigns for their help in the logistical planning, and we would like to single out Jim Bresch for his excellent and freely provided meteorological advice

Co-ordinated Airborne Studies in the Tropics (CAST)

This is the author accepted manuscript. The final version is available from the American Meteorological Society via http://dx.doi.org/10.1175/BAMS-D-14-00290.1The Co-ordinated Airborne Studies in the Tropics (CAST) project is studying the chemical composition of the atmosphere in the Tropical Warm Pool region to improve understanding of trace gas transport in convection. The main field activities of the CAST (Co-ordinated Airborne Studies in the Tropics) campaign took place in the West Pacific in January/February 2014. The field campaign was based in Guam (13.5°N, 144.8°E) using the UK FAAM BAe-146 atmospheric research aircraft and was coordinated with the ATTREX project with the unmanned Global Hawk and the CONTRAST campaign with the Gulfstream V aircraft. Together, the three aircraft were able to make detailed measurements of atmospheric structure and composition from the ocean surface to 20 km. These measurements are providing new information about the processes influencing halogen and ozone levels in the tropical West Pacific as well as the importance of trace gas transport in convection for the upper troposphere and stratosphere. The FAAM aircraft made a total of 25 flights between 1°S-14°N and 130°-155°E. It was used to sample at altitudes below 8 km with much of the time spent in the marine boundary layer. It measured a range of chemical species, and sampled extensively within the region of main inflow into the strong West Pacific convection. The CAST team also made ground-based measurements of a number of species (including daily ozonesondes) at the Atmospheric Radiation Measurement program site on Manus Island, Papua New Guinea (2.1°S, 147.4°E). This article presents an overview of the CAST project focussing on the design and operation of the West Pacific experiment. It additionally discusses some new developments in CAST, including flights of new instruments on the Global Hawk in February/March 2015.CAST is funded by NERC and STFC, with grant NE/ I030054/1 (lead award), NE/J006262/1, NE/J006238/1, NE/J006181/1, NE/J006211/1, NE/J006061/1, NE/J006157/1, NE/J006203/1, NE/J00619X/1, and NE/J006173/1. N. R. P. Harris was supported by a NERC Advanced Research Fellowship (NE/G014655/1). P. I. Palmer acknowledges his Royal Society Wolfson Research Merit Award. The BAe-146-301 Atmospheric Research Aircraft is flown by Directflight Ltd and managed by the Facility for Airborne Atmospheric Measurements, which is a joint entity of the Natural Environment Research Council and the Met Office. The authors thank the staff at FAAM, Directflight and Avalon Aero who worked so hard toward the success of the aircraft deployment in Guam, especially for their untiring efforts when spending an unforeseen 9 days in Chuuk. We thank the local staff at Chuuk and Palau, as well as the authorities in the Federated States of Micronesia for their help in facilitating our research flights. Special thanks go to the personnel associated with the ARM facility at Manus, Papua New Guinea without whose help the ground-based measurements would not have been possible. Thanks to the British Atmospheric Data Centre (BADC) for hosting our data and the NCAS Atmospheric Measurement Facility for providing the radiosonde and ground-based ozone equipment. Chlorophyll-a data used in Figure 1 were extracted using the Giovanni online data system, maintained by the NASA GES DISC. We also acknowledge the MODIS mission scientists and associated NASA personnel for the production of this data set. Finally we thank many individual associated with the ATTREX and CONTRAST campaigns for their help in the logistical planning, and we would like to single out Jim Bresch for his excellent and freely provided meteorological advice

Potential controls of isoprene in the surface ocean

Isoprene surface ocean concentrations and vertical distribution, atmospheric mixing ratios, and calculated sea-to-air fluxes spanning approximately 125° of latitude (80°N–45°S) over the Arctic and Atlantic Oceans are reported. Oceanic isoprene concentrations were associated with a number of concurrently monitored biological variables including chlorophyll a (Chl a), photoprotective pigments, integrated primary production (intPP), and cyanobacterial cell counts, with higher isoprene concentrations relative to all respective variables found at sea surface temperatures greater than 20°C. The correlation between isoprene and the sum of photoprotective carotenoids, which is reported here for the first time, was the most consistent across all cruises. Parameterizations based on linear regression analyses of these relationships perform well for Arctic and Atlantic data, producing a better fit to observations than an existing Chl a-based parameterization. Global extrapolation of isoprene surface water concentrations using satellite-derived Chl a and intPP reproduced general trends in the in situ data and absolute values within a factor of 2 between 60% and 85%, depending on the data set and algorithm used

Magnetic CoFe2O4@ melamine based hyper-crosslinked polymer: A multivalent dendronized nanostructure for fast bacteria capturing from real samples

Polymeric compounds are main types of advanced materials to prepare antibacterial coating as well as water treatment system hence this work was aimed to prepare a polymeric nanostructure with excellent bacteria capture efficiency. Dendronized melamine � resorcinol was synthesized by a condensation reaction. To simplify polymer collection from aqueous solutions, a magnetic nanocomposite of the polymer was also prepared. For this purpose, CoFe2O4 nanoparticles were synthesized by solid-state combustion route using cellulose as fuel. Bacteria removal efficiency was studied by uptake of Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria from water, milk and fruit juice samples. Effective parameter on the capturing efficiency including; solution pH, contact time and nanocomposite dosage were optimized. Results confirmed the positive role of presented nanostructure for fast capturing of bacterial pathogens with high efficiency (more than 99). © 201

Magnetic CoFe2O4@ melamine based hyper-crosslinked polymer: A multivalent dendronized nanostructure for fast bacteria capturing from real samples

Polymeric compounds are main types of advanced materials to prepare antibacterial coating as well as water treatment system hence this work was aimed to prepare a polymeric nanostructure with excellent bacteria capture efficiency. Dendronized melamine � resorcinol was synthesized by a condensation reaction. To simplify polymer collection from aqueous solutions, a magnetic nanocomposite of the polymer was also prepared. For this purpose, CoFe2O4 nanoparticles were synthesized by solid-state combustion route using cellulose as fuel. Bacteria removal efficiency was studied by uptake of Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria from water, milk and fruit juice samples. Effective parameter on the capturing efficiency including; solution pH, contact time and nanocomposite dosage were optimized. Results confirmed the positive role of presented nanostructure for fast capturing of bacterial pathogens with high efficiency (more than 99). © 201

A comparison of very short lived halocarbon (VSLS) and DMS aircraft measurements in the tropical west Pacific from CAST, ATTREX and CONTRAST

We present a comparison of aircraft measurements of halogenated very short lived substances (VSLSs) and dimethyl sulphide (DMS, C₂H₆S) from a co-ordinated campaign in January–February 2014 in the tropical west Pacific. Measurements were made on the NASA Global Hawk, NCAR Gulfstream-V High-performance Instrumented Airborne Platform for Environmental Research (GV HIAPER) and UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 (see Sect. 2.2) using four separate gas chromatography–mass spectrometry (GC-MS) instruments: one operated by the University of Miami (UoM), one from the National Center for Atmospheric Research (NCAR) and two from the University of York (UoY). DMS was measured on the BAe-146 and GV. The instruments were inter-calibrated for halocarbons during the campaign period using two gas standards on separate scales: a National Oceanic and Atmospheric Administration (NOAA) SX-3581 standard representative of clean low-hydrocarbon air, and an Essex canister prepared by UoM, representative of coastal air, which was higher in VSLS and hydrocarbon content. UoY and NCAR use the NOAA scale/standard for VSLS calibration, and UoM uses a scale based on dilutions of primary standards calibrated by GC with FID (flame ionisation detector) and AED (atomic emission detector). Analysis of the NOAA SX-3581 standard resulted in good agreement for CH₂Cl₂, CHCl₃, CHBr₃, CH₂Br₂, CH₂BrCl, CHBrCl₂, CHBr₂Cl, CH₃I, CH₂ICl and CH₂I₂ (average relative standard deviation (RSD)  <  10 %). Agreement was in general slightly poorer for the UoM Essex canister with an RSD of  <  13 %. Analyses of CHBrCl₂ and CHBr₃ in this standard however showed significant variability, most likely due to co-eluting contaminant peaks, and a high concentration of CHBr₃, respectively. These issues highlight the importance of calibration at atmospherically relevant concentrations ( ∼  0.5–5 ppt for VSLSs; see Fig. 5 for individual ranges). The UoY in situ GC-MS measurements on board the BAe-146 compare favourably with ambient data from NCAR and UoM; however the UoY whole-air samples showed a negative bias for some lower-volatility compounds. This systematic bias could be attributed to sample line losses. Considering their large spatial variability, DMS and CH₃I displayed good cross-platform agreement without any sampling bias, likely due to their higher volatility. After a correction was performed based upon the UoY in situ vs. whole-air data, all four instrument datasets show good agreement across a range of VSLSs, with combined mean absolute percentage errors (MAPEs) of the four platforms throughout the vertical profiles ranging between 2.2 (CH₂Br₂) and 15 (CH₃I) % across a large geographic area of the tropical west Pacific. This study shows that the international VSLS calibration scales and instrumental techniques discussed here are in generally good agreement (within ∼  10 % across a range of VSLSs), but that losses in aircraft sampling lines can add a major source of uncertainty. Overall, the measurement uncertainty of bromocarbons during these campaigns is much less than the uncertainty in the quantity of VSLS bromine estimated to reach the stratosphere of between 2 and 8 pptv