High-quality tall mast and wind lidar measurements over the North and Baltic Seas are used to validate the wind climatology produced from winds simulated by the Weather, Research and Forecasting (WRF) model in analysis mode. Biases in annual mean wind speed between model and observations at heights around 100 m are smaller than 3.2% at offshore sites, except for those that are affected by the wake of a wind farm or the coastline. These biases are smaller than those obtained by using winds directly from the reanalysis. We study the sensitivity of the WRF-simulated wind climatology to various model setup parameters. The results of the year-long sensitivity simulations show that the long-term mean wind speed simulated by the WRF model offshore in the region studied is quite insensitive to the global reanalysis, the number of vertical levels, and the horizontal resolution of the sea surface temperature used as lower boundary conditions. Also, the strength and form (grid vs spectral) of the nudging is quite irrelevant for the mean wind speed at 100 m. Large sensitivity is found to the choice of boundary layer parametrization, and to the length of the period that is discarded as spin-up to produce a wind climatology. It is found that the spin-up period for the boundary layer winds is likely larger than 12 h over land and could affect the wind climatology for points offshore for quite a distance downstream from the coast.

Changes in the diurnal precipitation cycle as the Madden–Julian oscillation (MJO) propagates through the Maritime Continent are investigated to explore the processes behind seaward-propagating precipitation northeast of New Guinea. Satellite rainfall estimates from TRMM 3B42 and the Climate Prediction Center morphing technique (CMORPH) are combined with simulations from the Weather Research and Forecasting (WRF) Model with a horizontal resolution of 4 km. Comparison with 24-h rain gauge measurements indicates that both satellite estimates and the WRF Model exhibit systematic biases. Despite these biases, the changing patterns of offshore precipitation with the passage of the MJO show good consistency between satellite estimates and the WRF Model. In the few days prior to the main MJO envelope, light background wind, relatively clear skies, and an increasingly moist environment promote favorable conditions for the diurnal precipitation cycle. Two distinct processes are identified: 100–200 km from the coast, precipitation moves offshore as a squall line with a propagation speed of 3–5 m s−1. Farther offshore, precipitation propagates with a speed close to 18 m s−1and is associated with an inertia–gravity wave generated by diurnally oscillating heating from radiative and moist convective processes over the land. A gravity wave signature is evident even after the MJO active period when there is little precipitation. By correcting for the background flow perpendicular to the coast, potential temperature anomalies for the lead-up, active, and follow-on MJO periods are shown to collapse to a remarkably invariant shape for a given time of day.

Genetic recombination is an important process during the evolution of many virus species and occurs particularly frequently amongst begomoviruses in the single stranded DNA virus family, Geminiviridae. As in many other recombining viruses it is apparent that non-random recombination breakpoint distributions observable within begomovirus genomes sampled from nature are the product of variations both in basal recombination rates across genomes and in the over-all viability of different recombinant genomes. Whereas factors influencing basal recombination rates might include local degrees of sequence similarity between recombining genomes, nucleic acid secondary structures and genomic sensitivity to nuclease attack or breakage, the viability of recombinant genomes could be influenced by the degree to which their co-evolved protein-protein and protein-nucleotide and nucleotide-nucleotide interactions are disreputable by recombination. Here we investigate patterns of recombination that occur over 120 day long experimental infections of tomato plants with the begomoviruses Tomato yellow leaf curl virus and Tomato leaf curl Comoros virus. We show that patterns of sequence exchange between these viruses can be extraordinarily complex and present clear evidence that factors such as local degrees of sequence similarity but not genomic secondary structure strongly influence where recombination breakpoints occur. It is also apparent from our experiment that over-all patterns of recombination are strongly influenced by selection against individual recombinants displaying disrupted intra-genomic interactions such as those required for proper protein and nucleic acid folding. Crucially, we find that selection favoring the preservation of co-evolved longer-range protein-protein and protein DNA interactions is so strong that its imprint can even be used to identify the exact sequence tracts involved in these interactions.