Large-scale circulation involves the interaction of the lower and middle-upper troposphere, influencing synoptic-scale circulation, regional climate, teleconnections, and paleoclimate proxies. Described by the westerly vortex and jetstreams, the subtropical ridge, vortex asymmetry, and the South Pacific Split Jet, it is a framework for interpreting the natural archive and proxies. Southern and Northern Hemisphere pressure fields are described through planetary wave modes and zonal wave number indices. Anticyclone, cyclone, subtropical, mid-latitude, and subpolar storm-track and blocking climatologies and their influence on climate and hydrological change are presented. The chapter covers synoptic circulation, classical air-mass types, their source regions and temperature/humidity characteristics, and air-mass streamline trajectories; tropical depressions and cyclone storm tracks, easterly waves, blocking, and subtropical cyclones; mid-latitude synoptic systems including frontal lows, cut-off lows, and cold air outbreaks; and tropical–extratropical interaction with cloud bands, tropical–temperate troughs, atmospheric rivers, and warm-air incursions to the poles.

This chapter covers methods used to extract and interpret paleoclimate time series of climate modes, surface ocean, hydroclimate, and sea-level variability. The coral reef environment is explored as an archive of sea-surface temperature and salinity, hydroclimate, tradewinds, cloud cover and ocean circulation, storms, and regional and global sea-level variability, using stable isotopes, trace element analysis, radioisotopes, ultraviolet, and x-ray stratigraphic methods. The comparative tropical terrestrial hydroclimate record is investigated through the tree-ring and speleothem archive using traditional (dendrochronology and stable isotopes) and emerging methods such as biomarkers. Tropical hydroclimate reconstructions are presented, with the current understanding of decadal-scale variability due to the PDO/IPO. The coral and bivalve shell archive is presented as a record of boundary current, variability of continental shelf wind and current, and marine heat waves. Case studies reconstruct coastal jet modes and marine heat wave events for the Peruvian Current, Peru–Chile, and the Ningaloo Current, western Australia, in conjunction with ENSO variability during the Holocene.

Weather regime type and frequency are key diagnostics to interpret regional climate. The statistical methods used to downscale the centres of action in the mean atmospheric state to their family of weather regimes (WR) according to climate mode phases are presented in detail. The North Atlantic–European region is used as an example of WR decomposition of the mean climate. The chapter focuses on the identification of WR types for each region of the Southern Hemisphere and their spatio-temporal variability in relation to climate mode phase. These are the reference WRs for the interpretation of synoptic paleoclimate in each of the climate proxy chapters that follow. WRs are presented for the Maritime Continent, northern and central Australia, South Pacific Convergence Zone, Tasman Sea, New Zealand and southwest Pacific, eastern Pacific, Brazil to Uruguay, southwest Africa, southern Africa, eastern Africa, subtropical western Australia, southwestern Australia, southeastern Australia, the south Indian, south Pacific, and south Atlantic sectors of the Southern Ocean, and coastal Antarctica, including Patagonian South America, the Antarctic Peninsula, and the East Antarctic.

This chapter focuses on the glaciochemistry of Antarctic ice cores and their applications as aerosol tracers of atmospheric, sea ice, and oceanic variability. Marine aerosol–climate relationships are discussed using marine boundary layer, air–sea exchange, and cloud science. Glaciochemistry theory is presented for interpreting marine ion concentrations in ice cores as circumAntarctic wind-field and paleoweather tracers, sea ice extent, concentration, and polynya tracers. Similarly, non-marine aerosol ion glaciochemistry is examined, with applications including nitrate concentration as polar stratosphere and katabatic wind-field proxies; non-sea-salt sulphate as a volcanism proxy; and mineral dust as long-range air-mass tracers. Dust typing and mineral fingerprinting methods are discussed to identify Southern Hemisphere source areas. Air mass trajectory methods, both forward and backward, are presented to relate ice core ion glaciochemistry and dust particles as aerosol tracers to reconstruct large-scale atmospheric circulation, climate mode, and regional weather regime history during the interglacial and glacial periods.

This chapter covers the response of tropical to subantarctic glaciers to variability in tropospheric and sea-surface temperature, lapse rates, and precipitation. Glacial behaviour is reflected in regional weather patterns: air mass transport, temperature, precipitation and humidity, insolation/cloud cover, wind speed, and large-scale circulation. Glacier types, climate zones, and physical processes are used to define the latitudinal continuum of climate–glacier coupling. The glacial archive is examined using indicators of glacial structure and geomorphology, their mapping, and geochronological methods. Glacier mass balance characteristics are defined by climate and glacier morphometrics, including equilibrium line altitude, vertical balance profiles, glacier tongue length, balance ratios, and accumulation–area, area–altitude, and geomorphic–altitude relationships. Glacier mass balance and reaction times are examined via energy balance, glacier dynamics, and flow-line modelling. Approaches to reconstructing glacial behaviour include numerical weather forecast modelling and synoptic typing based on ice core geochemistry and relationships to weather regimes and climate variability.

Synoptic paleoclimatology is an interdisciplinary approach, using atmospheric, oceanic, and earth sciences to connect paleoweather and paleoclimate. The weather regime approach to paleoclimatology identifies large-scale flow patterns in the atmosphere and ocean, their persistence or transience, and associated weather characteristics. Weather-event frequency is expressed in the paleoclimate signal. Paleoweather is explored within scaling climate modes of variability: latitudinal insolation and temperature gradients associated with orbital forcing, and internal dynamical modes of variability in the atmosphere and ocean. The chapter covers the modern global atmospheric pressure field and its geographic centres of action; the role of wind and wind stress on ocean circulation; ocean gyres and currents; and the surface ocean mixed layer. It explores climate mode teleconnections – the atmospheric bridge, oceanic tunnel and super-gyres, and the thermal bipolar seesaw – using statistical associations and dynamical processes. Low-frequency climate variability recorded by natural climate proxies is investigated with a focus on macroweather scales and climate memory.

Paleoclimate data assimilation is reviewed with respect to convergence between proxy reconstructions and model ensembles of large-scale climate modes and circulation for the Holocene and last millennium. The chapter reviews progress in interpreting climate mode behaviour and teleconnection stationarity, particularly the North Atlantic Oscillation, the El Niño–Southern Oscillation (ENSO), the Southern Annular Mode, Zonal Wave 3, and sea ice indices. It presents approaches to resolving future problem climates using weather regime knowledge and causal networks of physical systems as applications of synoptic paleoclimatology. These include the realisation of past and future regional precipitation and winds with problem warm climates associated with tropical expansion or amplification (zonal mean Hadley Cell response) and ENSO (bias and amplitude); mid-latitude storm tracks, westerly winds, and precipitation dipoles; and polar amplification, amplified planetary waves, and extreme mid-latitude weather. Examples of causal networks and internal variability analogues that incorporate paleoweather and climate memory are applied to project future marine heat waves and cold spells.

An overview of the global energy balance, atmosphere–ocean circulation, the Hadley and Ferrell Cells, and heat and moisture budgets forms the introduction to an examination of Southern Hemisphere circulation. The chapter is a primer for paleoclimatologists working on the natural archive from the tropics to the poles. The major circulation characteristics of the Southern Hemisphere are defined in descriptive terms. Low-latitude circulation is viewed through the tropical zonal pressure gradient and Walker Circulation; tropical easterlies, near-equatorial trough, and westerlies; the Intertropical Convergence Zone over the ocean basins, the Maritime Continent, Africa, and South America; and tropical/subtropical monsoons. The mid-high latitudes are explored through the mid-latitude westerlies, circumpolar trough, Antarctic coastal easterlies and coastal-slope winds, and the annual and semi-annual oscillations in pressure and temperature. The major climate modes, El Niño–Southern Oscillation (ENSO), Indian Ocean Dipole, ENSO diversity, tropical–extratropical interactions, the Pacific–South American modes, and the Southern Annular Mode are described in terms of air–sea interactions.