Peter Baines (academic)

Baines has worked on density-stratified fluids since his doctoral studies, with application to both the atmosphere and ocean. This led to a significant number of papers describing theoretical, numerical and experimental studies of the flow of density-stratified fluids over and around topography with a variety of two- and three-dimensional shapes. Whether fluid passes over an obstacle (an isolated mountain, say) or around it depends on a variety of factors (wind profile, stratification, mountain shape), and these studies have, in particular, been helpful in improving the representation of topographic effects in weather-forecasting models.[11] This work has included experimental studies of the flow of dense fluid downslope into density-stratified environments, which has identified a variety of differing flow regimes involving mixing, with applications to oceanic flows in particular. The impact of this work is contained within the book cited below.[12]

In a paper titled A fractal world of cloistered waves, Baines described that waves in stratified fluids in closed containers can have some strange properties, particularly if the container has sloping boundaries.[13]

Baines authored a book titled Topographic Effects in Stratified Flows in 1998, (paperback version in 1998), which utilizes both theory and practical experiments to describe the motion of homogeneous and density-stratified fluids and their flow over and around topography. It is generally regarded as the go-to book on this subject, with application to motion of both the atmosphere and ocean. In a review by Xin-she Yang from University of Leeds, the book is declared having "good balance of basic principles, theory, and experiment, where the comparison is made whenever possible, with a consistent attempt to provide a physical understanding of the phenomena involved." Yang also states that "This book is well organized, addressing a wide spectrum of important problems and properties of stratified flows."[14] N. F. Smyth writes that "this book represents a remarkable synthesis of a large body of work into a very readable and understandable form". Smyth also comments in the review that the book is "easy to follow" and "an excellent book" that is "well produced".[15] Don L. Boyer of Arizona State University considers the book as "an invaluable reference for students and research workers" and congratulated Baines for "very fine piece of work". Boyer also states that "one fact that cannot escape the reader is that the author, Dr. Baines combines the mastery of the analysis involved with an outstanding facility in laboratory experiment", which he considers "very rare indeed in the scientific community".[16]

Baines has studied oceanography along with stratified fluids, and published articles using the two research areas together. This has included a study of internal (baroclinic) ocean tides, generated by tidal flow over topography such as submarine ridges, continental shelves and slopes, submarine canyons and seamounts.[2]

In 1984, he led an observational study of the oceanic flow through Bass Strait, which involved the only measurements to date of this significant throughflow.[17] In 1989 he published a review paper about the oceanography of Australian waters as a whole, including the ocean currents and tides in the Indian and Southern Oceans, and the coastal oceanography of southern Australia.[18]

In 1987, Baines described the relationship between ocean current transports and electric potential differences across the Tasman Sea, measured using an ocean cable, and explained the connections between them.[19]

Baines worked on climate dynamics from 2005 till 2014 and published various research articles on topics that included the zonal structure of the Hadley circulation, and the effect of the African monsoon on the rainfall of southwest Western Australia. Baines also investigated decadal and multi-decadal variability in the context of climate change, and demonstrated that regional fluctuations in climate occur due to a variety of natural methods, as well as from artificially induced climate change. In 2007, with Chris Folland of the UK Meteorological Office, he identified and described a rapid global climate shift in the late 1960s, that is as yet unexplained.[20]

In 2010, Baines studied how climate changes affect global rainfall, and analyzed a century worth of data about the global sea surface temperature, to determine the fundamental patterns of climate fluctuations on time scales longer than ENSO, and to relate these fluctuations to probable dynamical processes.[21] In his article titled 'The effect of global dynamical factors on the inter-annual variability of land-based rainfall' in 2014 with B. Henley, Baines studied the factors having major impact on rainfall in the tropics and the mid-latitudes of Australia. His research concluded that seasonal rainfall in Australia is dependent on several dynamic processes but mostly on El Niño-Southern Oscillation and the Indian Ocean Dipole.[22]

Baines took on the research topic of volcano dynamics in 2005, with a paper with RSJ Sparks on supervolcanic eruptions, and this was extended in 2008 to the effects of varying latitude on such large eruptions.

In 2013 Baines, along with Selwyn Sacks, wrote an article entitled 'Atmospheric internal waves generated by explosive volcanic eruptions' for the UK Geological Society Memoirs volume on the Soufriere Hills volcano on Montserrat. This analysis followed barometric observations of this volcano that sporadically produces Vulcanian explosions spanning several minutes. The sudden addition of thermal energy results in the production of internal waves in the troposphere.[23]

Baines studied the dynamics of intrusions into a density-stratified cross flow and showed that when a buoyant fluid from a steady source such as a volcanic eruption is released into a stratified environment such as our atmosphere, the fluid reaches an equilibrium level after which it spreads in a homogenous manner.[24] This flow is controlled by the law of mass conservation and Bernoulli's equation. The results from this research are applicable in the study of geological sediments.