Terminalia catappa (Singapore almond).

T. catappa is a perennial tree species that has been extensively introduced into littoral habitats, coastal forests, gardens and parks to be used as an ornamental, shade tree, and sand-dune stabilizer (Orwa et al., 2009; ISSG, 2017). This species has become of the most common trees in littoral habitats and beaches across tropical and subtropical regions of America, India, southeastern Asia, and the Pacific Ocean, due in part to human-mediated introductions, the adaptation of its fruits to be dispersed over long-distances by sea currents and its tolerance to salt-spray, coastal-winds and drought conditions (Thomson and Evans, 2006; Brown and Cooprider, 2013). T. catappa is a prolific seed producer and fruits may remain viable for a long time, even after floating in salt water for considerable time periods. This species naturalizes readily in littoral habitats and has been listed as invasive in the United States (Florida and Hawaii), Brazil, the Bahamas, Cuba, Dominican Republic, Trinidad and Tobago, Puerto Rico and Virgin Islands where it is displacing native vegetation and altering coastal dynamics (Smith, 2010; Oviedo Prieto et al., 2012; Mir, 2012; Rojas-Sandoval and Acevedo-Rodríguez, 2015; FLEPPC, 2017; I3N-Brazil, 2017; ISSG, 2017).

Coastal winds drive a recruitment mechanism for estuarine fisheries

Coastal winds transport larval fish onshore or offshore which may contribute to estuarine recruitment, yet our understanding of the mechanism underlying this relationship is limited. Here, we show that larval abundance of coastally spawned species increased with weak to moderate upwelling favourable winds 14 days prior to sampling, reflecting increased nutrient and plankton availability for larval fish. A strong decline in larval abundance was observed following strong upwelling favourable winds while abundance increased with onshore (downwelling favourable) winds, in relation to offshore and onshore wind-driven transport. Subsequently, we show that effects of wind during the spawning period can be detected in lagged estuarine commercial fisheries catch rates of coastally spawned species (lagged by 2 – 8 years depending on species’ growth rates), representing the same mechanism proposed for larval fish. Upwelling favourable winds in the southeast Australian region have increased since 1850 while onshore winds have decreased, which may reduce larval recruitment to estuaries. Coastal winds are likely an important factor for estuarine recruitment in the east Australian region and future research on the estuarine recruitment of fish should incorporate coastal winds. As global winds are changing, it is important to investigate if this mechanism is applicable to other regions around the world where coastal winds are a key driver of upwelling.

Europe’s offshore winds assessed from SAR, ASCAT and WRF

Europe’s offshore wind resource mapping is part of the New European Wind Atlas (NEWA) international consortium effort. This study presents the results of analysis of Synthetic Aperture Radar (SAR) ocean wind maps based on Envisat and Sentinel-1 with a brief description of the wind retrieval process and Advanced SCATterometer (ASCAT) ocean wind maps. The wind statistics at 10m and 100m height using an extrapolation procedure involving simulated long-term stability over oceans is presented for both SAR and ASCAT. Furthermore, the Weather Research and Forecasting (WRF) offshore wind atlas of NEWA is presented. This has 3 km grid resolution with data every 30 minutes during 30 years from 1989 to 2018, while ASCAT has 12.5 km and SAR has 2 km resolution. Offshore mean wind speed maps at 100 m height from ASCAT, SAR, WRF and ERA5 at a European scale are compared. A case study on offshore winds near Crete compares SAR and WRF for flow from north, west and all directions. The paper highlights the ability of the WRF model to simulate the overall European wind climatology and the near coastal winds constrained by the resolution of the coastal topography in the WRF model simulations.

Are the Near-Antarctic Easterly Winds Weakening in Response to Enhancement of the Southern Annular Mode?

Previous studies have highlighted the sensitivity of the Southern Ocean circulation to the strengthening, poleward-shifting westerlies, associated with the increasingly positive southern annular mode (SAM). The impacts of the SAM have been hypothesized to weaken momentum input to the ocean from the easterly winds around the Antarctic margins. Using ERA-Interim data, the authors show that the circumpolar-averaged easterly wind stress has not weakened over the past 3–4 decades, and, if anything, has slightly strengthened by around 7%. However, there has been a substantial increase in the seasonality of the easterlies, with a weakening of the easterly winds during austral summer and a strengthening during winter. A similar trend in the seasonality of the easterlies is found in three other reanalysis products that compare favorably with Antarctic meteorological observations. The authors associate the strengthening of the easterly winds during winter with an increase in the pressure gradient between the coast and the pole. Although the trend in the overall easterly wind strength is small, the change in the seasonal cycle may be expected to reduce the shoreward Ekman transport of summer surface waters and also to admit more warm Circumpolar Deep Water to the continental shelf in summer. Changes in the seasonal cycle of the near-coastal winds may also project onto seasonal formation and export of sea ice, fluctuations in the strengths of the Weddell and Ross Gyres, and seasonal export of Antarctic Bottom Water from the continental shelf.

A Weather Eye on Coastal Winds

New satellite radar image-processing system provides wind speed maps with an unprecedented degree of precision. Such maps will help coastal communities prepare for wind-related hazards.