Abbreviation for Responsible National Oceanographic Data
Center, a facility established within the
framework of the IOC
IODE structure to take on the responsbility of
assisting the WDCs. This scheme was developed
to enable to international exchange system to cope with an increasing
variety and volume of oceanographic data being collected by providing
special data processing and compilation support for specific programs
and certain areas.
See the IODE Web site.
Abbreviation for RNODC from the
Southern Oceans, a data center commissioned in 1988 within
IODE to acquire the physical and chemical
data obtained by the international scientific community in cruises and
research programs carried out in the Southern Oceans, control their
quality, store them in standard format, and distribute them upon
This center is a part of CEADO.
RNODC-SOC Web site.
- roaring forties
The region between 40 and 50 S latitude where the prevailing
westerly winds blow largely unobstructed by land over the open oceans,
and also the winds themselves.
They are constant and of great velocity, whence comes the
term "roaring". The weather is stormy, rainy, and comparatively
mild in the wake of constantly appearing depressions. The land
areas that do obstruct them, the western mountainous coasts of
southern Chile, Tasmania and New Zealand, experience tremendous
rainfall through the year on the western sides (up to 100 in.)
and much less on the eastern sides (around 20 in.). These are
also known as brave west winds.
See statistically robust.
An instrument for measuring and transmitting upper-air meteorological
data. It is borne on a rocket (whence comes the name) and takes
data samples up to 76,000 meters, well above the 30,000 meter
limit of the similiar and complementary
Acronym for Reports of Oceanographic Cruises and Oceanographic
Programs, a program conceived by the IOC
in the late 1960s to provide a low level inventory for tracking
oceanographic data collected on research vessels. It is a form
to be completed by a scientist on each cruise that provides
various metadata about what kinds of data were taken on the
cruise. It was renamed the Cruise Summary Report (CSR) in 1990
but the acronym ROSCOP persists.
See the ROSCOP Web site where digitized forms of
collected ROSCOP info from the 1960s through the present
can be obtained.
Acronym for Reflective Optics System Imaging Spectrometer,
a compact airborne imaging spectrometer.
This device was designed for the detection of spectral fine
structure in coastal waters.
ROSIS Web site.
- Ross, James Clark
- Ross Sea
See Jacobs et al. (1970).
- Rossby, Carl-Gustav Arvid (1898-1957)
Rossby was born in Sweden and joined a group studying under
V. Bjerknes in 1918 after receiving his ``Kandidat'' in
theoretical mechanics. There he started his career in
meteorology as well as his interest in oceanography.
In 1921 he followed Bjerknes to the University of Leipzig
for a year and then returned to Stockholm in 1922 to a position
with the Swedish Meteorological Hydrologic Service.
Over the next three years he accompanied, as a meteorologist,
oceanographic expeditions to Jan Mayen in the Nordic Seas,
around the British Isles, and to Portugal and Madeira.
He also studied mathematical physics at the University of
Stockholm during this time and received his ``Licentiat''
In 1926 Rossby moved to the United States and continued
his research at the only extent meteorological center, the
Government Weather Bureau in Washington, D.C. He wrote
several significant papers on atmospheric turbulence
and stratospheric dynamics during this period and also
organized the first airway meterological service on an
experimental basis in California which provided the pattern
for future systems. In 1928 he organized the first university
level meteorological program in the United States at the
Massachusetts Institute of Technology 9MIT), in which he soon became
a full professor.
He spent eleven years at MIT and contributed to such areas as
the thermodynamics of air masses, turbulence in the atmosphere and
in the oceans, lateral mixing, and the interaction of the
ocean-atmosphere boundary layers. He gradually turned his
attentions to large-scale motions and the general circulation
of the atmosphere, to which he began to apply the concepts
of vorticity and momentum that permeate the field today.
In 1939 he became the assistant chief of research at the
U.S. Weather Bureau and in 1940 the chairman of the Department
of Meteorology at the University of Chicago, during which time
he developed his theory for the long waves in the atmosphere
that later came to be called Rossby waves.
During World War II he organized the training of military
meteorologists and continued his research on long waves in
the atmosphere. After the war he recruited many outstanding
future researchers for the University of Chicago and played
a significant role in the development of equations for the
prediction of weather using electronic computers. In 1947
he became the director of the newly formed Institute of
Meteorology in Stockholm and divided his time between there
and Chicago (although, for convenience, his American
affiliation was transferred to Woods Hole in the early 1950s.
At Stockholm Rossby's principal activities were concerned with
developing numerical prediction systems for European weather.
He also founded the geophysical journal Tellus. In 1954
he turned his attention to the field of geochemistry and also
became interested in deep circulation processes in the ocean.
He worked in these areas until his death in 1958.
- Rossby-gravity wave
See Yanai wave.
- Rossby number
A non-dimensional number expressing the ratio of inertial to
Coriolis forces in the atmosphere or
Rossby number is defined by
where U is a characteristic velocity scale, f the
Coriolis parameter, and
L a characteristic length scale. If the Rossby number
is large, then the effect of the Earth's rotation on the
phenomenon in question can be neglected. This is also
called the Kibel number.
- Rossby radius of deformation
The fundamental horizontal length scale in fluids that are
affected by both gravity and rotation. It is the length scale at
which rotation effects become as important as buoyancy effects.
In transient problems an initial disturbance at a scale small
compared to the Rossby radius will result in an adjustment
process about the same as would occur in a nonrotating system.
If the disturbance is on a scale comparable to the Rossby radius,
the Coriolis acceleration becomes as important as the pressure
gradient term and the response is markedly different than would
be seen in the nonrotating system.
In a homogeneous layer of fluid the
barotropic Rossby radius is
where c is the gravity wave propagation velocity
, g the
H the water depth, and
f the Coriolis parameter.
In the deep ocean where H is 4 or 5 km, the baroclinic radius is
around 2000 km, but on the continental shelves with depths
closer to 50 to 100 m it is around 200 km.
In a stratified fluid the baroclinic
Rossby radius is similarly computed, except that c is now the
wave speed of the nth baroclinic mode as would be found in
a normal mode decomposition of the
system. The baroclinic radius is a natural scale in the ocean
associated with boundary phenomena such as boundary currents,
fronts, and eddies. The first mode baroclinic radius is
typically around 10-30 km in the ocean. See
- Rossby wave
Large scale waves in the ocean or atmosphere whose restoring
force is the -effect of latitudinal variation of
the local vertical component of the earth's angular
rotation vector, i.e. the Coriolis force. In the atmosphere
they are easily observed as the large-scale meanders of the
mid-latitude jet stream that are responsible for prevailing
seasonal (via blocking) and
day-to-day weather patterns. They are more difficult to
detect in the ocean as their sea surface height signature
is on the order of 10 cm, their propagation speeds of order
10 cm/s, and their wavelengths hundreds to thousands of
Rossby waves in the ocean are responsible for establishing
the westward intensification of circulation gyres, the Gulf
Stream being one example of this.
They are also the dynamic mechanism for the transient adjustment
of the ocean to changes in large-scale atmospheric forcing, e.g.
information is transmitted from the tropical oceans to mid- and
high-latitudes via Rossby waves acting in concert with coastal
They are generated by wind
and buoyancy forcing at the eastern boundaries and over
the ocean interior. They are also known to be generated by
perturbations along the eastern boundaries caused by coastal
trapped waves originating at low latitudes. They subsequently
freely propagate away from their source regions.
Standard theory derives the properties of freely propagating
Rossby waves from the linearized equations of motion for
large-scale, low-frequency motion about a state of rest, which
yields an equation for normal modes.
These normal modes can be found by specifying surface and bottom
boundary conditions and solving an eigenvalue problem that depends
only on the local stratification. There are an infinite number
of wave modes ordered by decreasing phase speed, which are westward
for all modes. Solutions for low frequencies and long wavelengths
are zonally nondispersive, i.e. the phase speed is independent of
The lowest mode is the barotropic mode. It is uniform vertically
and propagates across an ocean basin in about a week. The next gravest, or
first baroclinic, mode is surface intensified, depends strongly on
the stratification profile, has a velocity profile that changes sign
at the depth of the thermocline, and
takes months to cross the same basin as the first mode does in a week.
The surface height variations of this mode are mirrored as thermocline
depth variations of the opposite sign, which are also about three
orders of magnitude larger, i.e. a 5 cm surface elevation variation would
correspond to a 50 m depression in the thermocline.
See Platzman (1968), Dickinson (1978) and
- Rothamsted model
A soil turnover model used to explore the time lags involved in soil
carbon sequestration and to link CO2-induced effects on plant
productivity with decomposition. Plant residues are
divided into two components, the first being decomposable plant
matter (DPM) which includes simple compounds subject to rapid uptake,
transformation, and mineralization by decomposers and with a turnover
time of 0.1 year. The second is recalcitrant plant matter (RPM),
containing components such as lignin that are not easily decomposed
and having a turnover time of 3 years. Soil humus is divided into
three components. The first is soil biomass (BIO), with a turnover time
of 1.5 years and composed of mostly live microbes and microbial
products such as extracellular enzymes. The second is active soil
humus (HUM), with a turnover time of 50 years and consisting of organic compounds
that are either protected physically or exist in forms that are biologically
resistant to decomposition. The final component is inert soil organic
matter (IOM), consisting of chemically refractory and physically
protected froms with turnover times of 1000 years or more.
See Jenkinson (1990).
- roughness height
In atmospheric boundary layer dynamics, the height above a surface where
the wind speed reaches zero. This is used when surface irregularities
are larger than the 1 mm depth of the layer where molecular diffusion
dominates and an analogous ``turbulent'' diffusion depth is needed.
It is a constant in expressions
used to find the logarithmic velocity profiles in boundary layers,
and ranges from about a millimeter for average seas to more than
a meter for cities with tall buildings.
See Hartmann (1994).
Acronym for Remote Ocean Wave Spectrometer, an instrument
which uses the specular backscatter from a rotating near-nadir
radar to estimate the two-dimensional ocean surface wave
See Jackson (1987).
- Royal Greenwich Observatory (RGO)
A observatory founded in Greenwich, England in 1675 by Charles II.
During most of its history its main aim has been to provide fundamental
astrometric measures, and accurate time service, and almanacs and
predictions for use by navigators and surveyors. The development
of astrophysics in the last century has changed its emphasis to
that of investigative science, with its present role being the
provision, operation and maintenance of the main optical telescopes
for British, Dutch, Irish and Spanish astronomers (with the telescopes
now located on the island of La Palma in the Canaries). At the main
RGO center (now at Cambridge) teams design and supervise the
building of telescopes and the complex auxiliary instrumentation
used to analyze the faint light coming from distant astronomical
See the RGO Web site.
- Royal Meteorological Society
An organization founded in 1850 under a Royal Charter for the
advancement of meteorological science. It does so by publishing
journals and other publications, holding meetings, offering
field courses, giving grants, and offering professional
accreditation. Further details can be found at their
Abbreviation for Rosensteil School and Marine and
See the RSMAS Web site.
See Regional Stratigraphic Scale.
- Rumford, Count
See Benjamin Thompson.
The first of two ages in the
Oligocene epoch (coincidental with the
Early Oligocene), lasting from 36.6 to 30.0 Ma. It is preceded by
the Priabonian age of
the Eocene epoch and followed by
the Chattian age.
Abbreviation for research vessel.
Research Vessel Technical Enhancement Committee.