Operational Use and Impact of Satellite Remotely Sensed Ocean Surface Vector Winds in the Marine Warning and Forecasting Environment

Rhodesia, Corn MillColorVolume 81, Page

Community Review of Southern Ocean Satellite Data Needs

This review represents the Southern Ocean community’s satellite data needs for the coming decade. Developed through widespread engagement, and incorporating perspectives from a range of stakeholders (both research and operational), it is designed as an important community-driven strategy paper that provides the rationale and information required for future planning and investment. The Southern Ocean is vast but globally connected, and the communities that require satellite-derived data in the region are diverse. This review includes many observable variables, including sea-ice properties, sea-surface temperature, sea-surface height, atmospheric parameters, marine biology (both micro and macro) and related activities, terrestrial cryospheric connections, sea-surface salinity, and a discussion of coincident and in situ data collection. Recommendations include commitment to data continuity, increase in particular capabilities (sensor types, spatial, temporal), improvements in dissemination of data/products/uncertainties, and innovation in calibration/validation capabilities. Full recommendations are detailed by variable as well as summarized. This review provides a starting point for scientists to understand more about Southern Ocean processes and their global roles, for funders to understand the desires of the community, for commercial operators to safely conduct their activities in the Southern Ocean, and for space agencies to gain greater impact from Southern Ocean-related acquisitions and missions.The authors acknowledge the Climate at the Cryosphere program and the Southern Ocean Observing System for initiating this community effort, WCRP, SCAR, and SCOR for endorsing the effort, and CliC, SOOS, and SCAR for supporting authors’ travel for collaboration on the review. Jamie Shutler’s time on this review was funded by the European Space Agency project OceanFlux Greenhouse Gases Evolution (Contract number 4000112091/14/I-LG)

Observational studies of scatterometer ocean vector winds in the presence of dynamic air-sea interactions

Ocean vector wind measurements produced by satellite scatterometers are used in many applications across many disciplines, from forcing ocean circulation models and improving weather forecasts, to aiding in rescue operations and helping marine management services, and even mapping energy resources. However, a scatterometer does not in fact measure wind directly; received radar backscatter is proportional to the roughness of the ocean\u27s surface, which is primarily modified by wind speed and direction. As scatterometry has evolved in recent decades, highly calibrated geophysical model functions have been designed to transform this received backscatter into vector winds. Because these products are used in so many applications, it is crucial to understand any limitations of this process. For instance, a number of assumptions are routinely invoked when interpreting scatterometer retrievals in areas of complex air-sea dynamics without, perhaps, sufficient justification from supporting observations. This dissertation uses satellite data, in situ measurements, and model simulations to evaluate these assumptions. Robustness is assured by using multiple types of satellite scatterometer data from different sensors and of different resolutions, including an experimental ultra-high resolution product that first required validation in the region of study. After this validation survey, a subsequent investigation used the multiple data resolutions to focus on the influence of ocean surface currents on scatterometer retrievals. Collocated scatterometer and buoy wind data along with buoy surface current measurements support the theory that scatterometer winds respond to the relative motion of the ocean surface; in other words, that they can effectively be considered current-relative, as has been generally assumed. Another major control on scatterometer retrievals is atmospheric stability, which affects both surface roughness and wind shear. A study using wind, stress, temperature, and pressure measurements at a mooring in the Gulf Stream as well as collocated scatterometer data proved that the scatterometer responds as expected to changes in stability. Therefore, scatterometer retrievals can effectively be used to evaluate changes in wind due to speed adjustment over temperature fronts. Given the conclusions of these individual studies, this work collectively solidifies decades of theory and validates the use of scatterometer winds in areas of complex air-sea interaction

Environmental regimes in the Caribbean and implications for the dynamics and distribution of its coral reefs

Over evolutionary time coral reefs have been exposed to the influence of diverse environmental forces which have determined their structure and function. However, the climate of the earth is changing, affecting many biological systems, including coral reefs. Through this thesis the static and dynamic environment of the Caribbean basin was characterized using remote sensing and in situ data sources. This information was used to understand how present environmental conditions have shaped reef ecosystems and how the changing climate might jeopardize them. Focusing on physical constraints that drive many aspects of coastal ecology, a region-wide categorisation of the Physical Environments of the Caribbean Sea (PECS) was developed. The classification approach is hierarchical; including a first level of 16 physicochemical provinces based on sea surface temperature, turbidity and salinity data; and a second level considering mechanical disturbance from wave exposure and hurricanes. The PECS categorisation will facilitate comparative analyses and inform the stratification of studies across environmental provinces in the region. Montastraea spp. forereef habitats have the highest biodiversity and support the largest number of ecosystem processes and services in the Caribbean. One of the aspects of the physical environment, wave exposure, was used to predict the distribution of these habitats in the Caribbean basin with high accuracy (79%). The distribution of the habitat is constrained in environments of high exposure, a pattern likely to be driven by high rates of chronic sediment scour that constrain recruitment. This approach constitutes a fast and inexpensive alternative to traditional habitat mapping and complements global efforts to map reef extent. Recent changes in temperature have impacted ecosystem function across the globe. However, the nature of the responses has depended upon the rate of change of temperature and the season when the changes occur, which are spatially variable. In the Caribbean Sea, temperature trends are highly variable in space (ranging from -0.20 to 0.54°C decade-1) and most of the warming has been due to increases in summer temperatures. The highly detailed spatial and temporal patterns assessed can be used to elucidate observed ecological responses to climatic change in the region. In the face of increased temperatures it has been suggested that reefs may become increasingly restricted to locations of naturally low thermal stress, such as upwelling areas. However, when analysing the degree to which seasonal upwelling reduces the local thermal stress experienced by corals, it is clear that upwelling areas do not always offer meaningful protection. Hypothesised areas need to be assessed individually in order to evaluate their capacity as a refuge against climate change. In this thesis large progress has been made in assessing the ocean climate of the Caribbean basin by quantifying spatial patterns and their rate of change. Although some insight into the consequences of these seascape patterns to the function and distribution of marine systems has been provided, more can be done to fully exploit the datasets produced