Geophysical Fluid Dynamics Laboratory

About: Geophysical Fluid Dynamics Laboratory is a facility organization based out in Princeton, New Jersey, United States. It is known for research contribution in the topics: Climate model & Climate change. The organization has 525 authors who have published 2432 publications receiving 264545 citations. The organization is also known as: GFDL.

Stages in the energetics of baroclinic systems

Abstract: The results from several idealized and case studies are drawn together to form a comprehensive picture of “downstream baroclinic evolution” using local energetics. This new viewpoint offers a complementary alternative to the more conventional descriptions of cyclone development. These additional insights are made possible largely because the local energetics approach permits one to define an energy flux vector which accurately describes the direction of energy dispersion and quantifies the role of neighboring systems in local development. In this view, the development of a system's energetics is divided into three stages. In Stage 1, a pre-existing disturbance well upstream of an incipient trough loses energy via ageostrophic geopotential fluxes directed downstream through the intervening ridge, generating a new energy center there. In Stage 2, this new energy center grows vigorously, at first due to the convergence of these fluxes, and later by baroclinic conversion as well. As the center matures, it begins to export energy via geopotential fluxes to the eastern side of the trough, initiating yet another energy center. In Stage 3, this new energy center continues to grow while that on the western side of the trough decays due to a dwinding supply of energy via fluxes from the older upstream system and also as a consequence of its own export of energy downstream. As the eastern energy center matures, it exports energy further downstream, and the sequence begins anew. The USA “Blizzard of'93” is used as a new case study to test the limits to which this conceptual sequence might apply, as well as to augment the current limited set of case studies. It is shown that, despite the extraordinary magnitude of the event, the evolution of the trough associated with the Blizzard fits the conceptual picture of downstream baroclinic evolution quite well, with geopotential fluxes playing a critical role in three respects. First, fluxes from an old, decaying system in the Pacific were convergent over the west coast of North America, creating a kinetic energy center there and modifying the jet, resulting in a large extension of the overall kinetic energy center well into Mexico. Second, energy fluxes from this extension of the northwesterly flow were strongly convergent east of the trough, producing explosive growth of kinetic energy over the northwestern Gulf of Mexico, with baroclinic conversion following shortly thereafter. Lastly, the kinetic energy generated by the vigorous baroclinic conversion in the cold advection on the west side of the trough was very effectively transferred to the energy center on the east side of the trough via geopotential fluxes. DOI: 10.1034/j.1600-0870.1995.00108.x

Past and Future Changes in Extreme Sea Levels and Waves

Abstract: (1) Proudman Oceanographic Laboratory, Liverpool, UK (plw@pol.ac.uk) (2) The Hadley Centre, Met Office, UK (jason.lowe@metoffice.gov.uk) (3) Geophysical Fluid Dynamics Laboratory, Princeton, USA (tom.knutson@noaa.gov) (4) The Hadley Centre, Met Office, UK (ruth.mcdonald@metoffice.gov.uk) (5) CSIRO, Aspendale, Australia (kathleen.mcinnes@csiro.au) (6) GKSS, Geesthacht, Germany (woth@gkss.de) (7) GKSS, Geesthacht, Germany (storch@gkss.de) (8) Proudman Oceanographic Laboratory, Liverpool, UK (jaw@pol.ac.uk) (9) Environment Canada, Downsview, Canada (val.swail@ec.gc.ca) (10) Dalhousie University, Halifax, Canada (natacha.bernier@phys.ocean.dal.ca) (11) P.P. Shirshov Institute of Oceanology, Moscow, Russia (gul@sail.msk.ru) (12) Proudman Oceanographic Laboratory, Liverpool, UK (kevinh@pol.ac.uk) (13) National Institute of Oceanography, Goa, India (unni@darya.nio.org) (14) University of Hobart, Tasmania, Australia (john.hunter@utas.edu.au)

Increase of global monsoon area and precipitation under global warming: A robust signal?

Abstract: [1] Monsoons, the most energetic tropical climate system, exert a great social and economic impact upon billions of people around the world. The global monsoon precipitation had an increasing trend over the past three decades. Whether or not this increasing trend will continue in the 21st century is investigated, based on simulations of three high-resolution atmospheric general circulation models that were forced by different future sea surface temperature (SST) warming patterns. The results show that the global monsoon area, precipitation and intensity all increase consistently among the model projections. This indicates that the strengthened global monsoon is a robust signal across the models and SST patterns explored here. The increase of the global monsoon precipitation is attributed to the increases of moisture convergence and surface evaporation. The former is caused by the increase of atmospheric water vapor and the latter is due to the increase of SST. The effect of the moisture and evaporation increase is offset to a certain extent by the weakening of the monsoon circulation.

Eastern Boundary Currents and Coastal Upwelling

Abstract: The adjustment of the eastern coastal zone of an inviscid ocean with vertical walls to a change in wind conditions occurs in two stages. After the propagation of a Kelvin wave across the forced region in a time Tk which is of the order of a day or two, the coastal upwelling zone is temporarily in equilibrium with the wind. Further adjustment occurs after a time TR, which is of the order of a few mouths, when westward Rossby dispersion of the coastal jet becomes important. These time scales define three frequency ranges that characterize the response to fluctuating winds with period P. 1) At high frequencies (P ≲ Tk) short Kelvin waves can destroy coherence between the forcing and response, alonshore coherence of oceanic variables is small, and the spectrum of the response is red even if that of the forcing is white. The offshore wale of the response is the radius of deformation. Poleward phase propagation at Kelvin wave speed c in unforced regions and at speed 2c in the forced region is prominent...