[1] Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England
[2] Univ Manchester, Inst Sci & Technol, Atmospher Sci Grp, Dept Phys, Manchester M60 1QD, Lancs, England
[3] Univ Sunderland, Ctr Marine & Atmospher Sci, Sunderland SR2 7BW, England