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Featured researches published by Rana A. Fine.


Journal of Geophysical Research | 1991

Observations of the Mindanao Current during the western equatorial Pacific Ocean circulation study

Roger Lukas; Eric Firing; Peter Hacker; Philip L. Richardson; Curtis A. Collins; Rana A. Fine; Richard H. Gammon

The Western Equatorial Pacific Ocean Circulation Study (WEPOCS) III expedition was conducted from June 18 through July 31, 1988, in the far western equatorial Pacific Ocean to observe the low-latitude western boundary circulation there, with emphasis on the Mindanao Current. This survey provides the first quasi-synoptic set of current measurements which resolve all of the important upper-ocean currents in the western tropical Pacific. Observations were made of the temperature, salinity, dissolved oxygen, and current profiles with depth; of water mass properties including transient tracers; and of evolving surface flows with a dense array of Lagrangian drifters. This paper provides a summary of the measurements and a preliminary description of the results. The Mindanao Current was found to be a narrow, southward-flowing current along the eastward side of the southern Philippine Islands, extending from 14°N to the south end of Mindanao near 6°N, where it then separates from the coast and penetrates into the Celebes Sea. The current strengthens to the south and is narrowest at 10°N. Direct current measurements reveal transports in the upper 300 m increasing from 13 Sv to 33 Sv (1 Sverdrup = 1 × 106 m3 s−1) between 10°N and 5.5°N. A portion of the Mindanao Current appears to recurve cyclonically in the Celebes Sea to feed the North Equatorial Countercurrent, merging with waters from the South Equatorial Current and the New Guinea Coastal Undercurrent. Another portion of the Mindanao Current appears to flow directly into the NECC without entering the Celebes Sea. The turning of the currents into the NECC is associated with the Mindanao and Halmahera eddies.


Progress in Oceanography | 1989

Source waters of the Pacific Equatorial Undercurrent

Mizuki Tsuchiya; Roger Lukas; Rana A. Fine; Eric Firing; Eric Lindstrom

Abstract Hydrographic and direct current measurements were made north and east Papua New Guinea in June–August 1985 and January–February 1986 as part of the Western Equatorial Pacific Ocean Circulation Study (WEPOCS). Analyses of the data indicate that the major portion of the water in the Equatorial Undercurrent at its beginning north of Papua New Guinea is supplied from the south by a narrow western boundary undercurrent (New Guinea Coastal Undercurrent) transporting high-salinity, low-tritium, high-oxygen, low-nutrient water from the Solomon Sea northwestward along the north coast of Papua New Guinea through the Vitiaz Strait. The New Guinea Coastal Undercurrent has a maximum speed of 40–70 cm s −1 at a depth of about 200 m. It is a permanent feature despite the reversals of the wind and the surface current during the period of the northwest monsoon in austral summer. Its transport through the Vitiaz Strait is as high as 8 × 10 6 m 3 s −1 , which is of the same magnitude as the Equatorial Undercurrent transport at 143°E. The New Guinea Coastal Undercurrent revealed by the WEPOCS data is consistent with the low-latitude equatorward western boundary current implied in a calculation of the Sverdrup transport based on the observed wind-stress distribution for the tropical Pacific Ocean. High-salinity, low-tritium, low -oxygen, high -nutrient water which flows westward into the Bismarck Sea passing north of the Solomon Islands is entrained into the Equatorial Undercurrent north of New Ireland and returns to the east, resulting in a down-stream increae in the Undercurrent transport. Low-salinity, high-tritium, high-nutrient water of eastern North Pacific origin also contributes to the Equatorial Undercurrent in its source area west of the WEPOCS region. However, there is no evidence that northern waters are being continuously entrained into the Undercurrent in the WEPOCS region.


Journal of Chemical Physics | 1973

Compressibility of water as a function of temperature and pressure

Rana A. Fine; Frank J. Millero

The isothermal compressibility of water from 0 to 100 °C and 0 to 1000 bar has been determined from Wilsons sound velocity measurements which have been normalized to Kells 1 atm values. The isothermal compressibilities determined from the sound velocities have been fit, with a maximum deviation in compressibility of ± 0.016 × 10−6 bar−1, to an extended bulk modulus equation V 0 P/(V 0‐V P ) = B + A 1 P + A 2 P 2, where V 0 and V P are the specific volume at an applied pressure of zero and P; and B, A 1, and A 2 are temperature dependent constants. Our specific volume results are in reasonable agreement with the work of Kell and Whalley at low pressures; however, our results at high pressures (1000 bar) disagree by as much as 169 ppm (the average deviation is approximately 115 ppm). A comparison of the compressibilities indicates a parabolic shift in Kell and Whalleys work with a maximum of approximately 0.205 × 10−6 bar−1 at 400 bar and 5 °C. Since the velocity of sound data is extremely reliable (± 0.2 m/sec) and the maximum error in the compressibilities derived from the sound data is within ± 0.016 × 10−6 bar−1, our PVT results based upon the sound data are more accurate than any direct measurements made to date.


Deep-sea Research Part Ii-topical Studies in Oceanography | 1993

Maintenance of the low-oxygen layer in the central Arabian Sea

Donald B. Olson; Gary L. Hitchcock; Rana A. Fine; Bruce A. Warren

Abstract An intermediate depth layer, approximately 1 km thick, in the northwestern Indian Ocean contains essentially no detectable dissolved oxygen. Previous suggestions for primary causes of this feature have been: (a) very slow movement within the layer, allowing a long time for organic decomposition to consume the oxygen; (b) very large local consumption rates, resulting from enormous productivity in the surface layer; or (c) low oxygen concentrations in the waters entering the layer from the south, due to their long transit from their sea-surface sources. Observations reported here of a transient anthropogenic trace gas, trichlorofluoromethane (F-11 or freon 11), however, demonstrate that the residence time for water in the low-oxygen layer is not espciallt long, about 10 years. Concurrent summertime measurements of surface productivity, while high, preclude an exceptional mean consumption rate at depth. An oxygen budget for the layer supports the idea that the near-zero concentration is maintained by moderate consumption applied to waters with initially low oxygen concentration that pass through the layer at moderate speed.


Journal of Geophysical Research | 2000

Tracing the flow of North Atlantic Deep Water using chlorofluorocarbons

William M. Smethie; Rana A. Fine; Alfred Putzka; E. Peter Jones

Chlorofluorocarbon (CFC) and hydrographic data collected in the North Atlantic in the late 1980s and early 1990s are used to confirm and add to earlier work on the large-scale circulation pathways and timescales for the spreading of North Atlantic Deep Water (NADW) components and how these components relate to the hydrographic structure. Throughout the western North Atlantic, high CFC concentrations are coincident with newly formed NADW components of Upper Labrador Sea Water (ULSW), Classical Labrador Sea Water (CLSW), and Overflow Waters (OW). ULSW is marked by a CFC maximum throughout the western subtropical and tropical Atlantic, and CLSW is marked by a CFC maximum north of 38°N in data collected in 1990–1992. Iceland-Scotland Overflow Water (ISOW) splits into two branches in the eastern basin, with one branch entering the western basin where it mixes with Denmark Strait Overflow Water (DSOW) and the densest branch flows southward along the bottom in the eastern basin. DSOW contributes the largest portion of the CFC signal in OW. It is estimated that these NADW components are at 60–75% equilibrium with the CFC concentration in the atmosphere at the time of formation. The large-scale data set confirms that NADW spreads southward by complex pathways involving advection in the Deep Western Boundary Current (DWBC), recirculation in deep gyres, and mixing. Maps of the CFC distribution show that properties within the gyres are relatively homogeneous, particularly for OW, and there is a profound change at the gyre boundaries. The density of the core of ULSW increases in the equatorward direction because of entrainment by overlying northward flowing Upper Circumpolar Water and at the equator, ULSW has the same density as CLSW in the subtropics but is warmer and saltier. The density of OW decreases between the subpolar region and the subtropics. This is caused by the least dense part of OW exiting the subpolar region in the DWBC, while the densest component recirculates in the subpolar basins. Some variability is observed in OW density in the subtropics and tropics because of variability in mixing with Antarctic Bottom Water and changes in the subtropics that are probably related to the transport of different vintages of DSOW. Ages derived from CFC ratios show that the NADW components of northern origin spread throughout the western North Atlantic within 25–30 years. This corresponds to a spreading rate of 1–2 cm s−1 and is comparable to the time a climate anomaly introduced into the subpolar North Atlantic will take to penetrate the entire western North Atlantic Ocean.


Journal of Chemical Physics | 1977

The equation of state of pure water determined from sound speeds

Chen Tung Chen; Rana A. Fine; Frank J. Millero

The equation of state of water valid over the range 0–100 °C and 0–1000 bar has been determined from the high pressure sound velocities of Wilson, which were reanalyzed by Chen and Millero. The equation of state has a maximum error of ±0.01 bar−1 in isothermal compressibility and is in the form of a secant bulk modulus: K=V0P/(V0−V) =K0+AP+BP2, where K, K0, and V, V0 are the secant bulk moduli and specific volumes at applied pressures P and 0 (1 atm), respectively; A and B are temperature dependent parameters. The good agreement (to within 20×10−6 cm3 g−1) of specific volumes calculated using the above equation with those obtained from other modifications of the Wilson sound velocity data demonstrates the reliability of the sound velocity method for determining equations of state.


Deep-sea Research Part I-oceanographic Research Papers | 1993

Circulation of Antarctic intermediate water in the South Indian Ocean

Rana A. Fine

Chlorofluorocarbon (CFC) and hydrographic data collected on the R.R.S. Charles Darwin Cruise 29 along 32°S during November-December 1987, are used to examine the circulation in the South Indian Ocean. The emphasis is on Antarctic Intermediate Water (AAIW); bottom waters and mode waters are also examined. Bottom waters entering in the western boundary of the Crozet Basin (about 60°E) and in the Mozambique Basin (about 40°E) have low concentrations of anthropogenic CFCs. The rest of the bottom and deep waters up to about 2000 m have concentrations that are below blank levels. Above the intermediate waters there are injections of mode waters, which are progressively denser in the eastward direction. They form a broad subsurface CFC maximum between 200 and 400 m. The injections of recently ventilated (with respect to CFCs and oxygen) Subantarctic Mode Waters (SAMWs) at different densities indicate that there is considerable exchange between the subtropical and subantarctic regions. The tracer data presented show that the circulation of AAIW in the South Indian Ocean is different from that in the South Atlantic and South Pacific oceans in several ways. (1) The most recently ventilated AAIW is observed in a compact anticyclonic gyre west of 72°E. The shallow topography (e.g. that extending northeastward from the Kerguelen Plateau) may deflect and limit the eastward extent of the most recently ventilated AAIW. As a consequence, there is a zonal offset in the South Indian Ocean of the location of the most recently ventilated SAMW and AAIW, which does not occur in the other two oceans. The strongest component of SAMW is in the east, while the AAIW is strongest in the western-central South Indian Ocean. The offset results in a higher vertical gradient in CFCs in the east. (2) The Agulhas Current may impede input of AAIW along the western boundary. (3) Tracers are consistent with an inter-ocean flow from the South Pacific into the Eastern Indian Ocean, similar to the South Atlantic to Indian linkage. (4) It appears that the high wind stress curl forces an equatorward component of the circulation that is strongest around 60°E. As a result the highest concentrations of CFCs and oxygens in bottom waters, AAIW, and the lightest component of SAMW are co-located along the 32°S track at about 60°E. Thus, the most recently ventilated circumpolar waters, participating in both the wind driven and the thermohaline circulations, follow similar paths equatorward into the subtropical Indian Ocean.


Geophysical Research Letters | 1998

The arrival of recently formed Labrador Sea Water in the deep western boundary current at 26.5 °N

Robert L. Molinari; Rana A. Fine; W. Douglas Wilson; Ruth G. Curry; Jeff Abell; Michael S. McCartney

The Deep Western Boundary Current (DWBC) of the North Atlantic is a principal conduit between the formation region for Labrador Sea Water (LSW) and the oceanic interior to the south. Time series (1985–1997) of hydrographic properties obtained in the DWBC at 26.5°N show that prior to 1994, temperature, salinity, and transient tracer properties within the LSW density range showed little indication of recently formed parcels. Properties characteristic of a newer version of LSW (cooler, fresher, and higher tracer concentrations) were observed beginning in 1994 and continuing through 1997. Longer time series of temperature and salinity, developed from a regional data base, show both the 1994 and a 1980–1981 event in the Abaco region. Both events are consistent with anomalies in the Labrador Sea that occurred some 10 years earlier. The 10-year transit time from the Labrador Sea to 26.5°N is less than the 18-year transit time inferred from earlier studies.


Journal of Physical Oceanography | 1987

The penetration of tritium into the tropical Pacific

Rana A. Fine; William H. Peterson; H. Göte Östlund

Abstract The persistence of subsurface tritium maxima coincident with the Equatorial Currents is used to show that advection along isopycnals by the mean wind-driven circulation is the dominant process in the at most 14-year time scale for the penetration of high northern latitude water to the equator (above 26.2 sigma-theta). Ventilation of the equatorial Pacific thermocline from the north contrasts sharply with the equatorial Atlantic thermocline which is ventilated from the south. The most striking manifestation of the North Pacific circulation is evidenced by a tritium maximum and salinity minimum at the equator between 145° and 125°W located above 25.6 sigma-theta. It shows that regardless of time of sampling the eastern&sol/central equator has received the moat high latitude water, probably as a consequence of recirculation by the Equatorial Currents. Between the same meridians there is a tritium maximum on and north of the equator at the surface, which is interpreted as an expression of upwelling. ...


Journal of Physical Oceanography | 1981

Circulation of Tritium in the Pacific Ocean

Rana A. Fine; Joseph L. Reid; H. Göte Östlund

Abstract The input of bomb tritium into the high-latitude Northern Hemisphere waters has demonstrated the spread of a tracer in three dimensions in the North Pacific Ocean. Subsurface tritium maxima in middle and low latitudes clearly show the importance of lateral mixing (along isopycnals) in the upper waters. The tritium pattern as mapped on isopycnal surfaces puts definite time bounds on the exchange between the subtropical anticyclonic gyre of the North Pacific and both the subarctic cyclonic gyre and the system of zonal flows in the equatorial region. The penetration of bomb tritium to depths below 1000 m in the western North Pacific Ocean shows that these waters have been ventilated at least partially in the past 17 years of the post-bomb era. From the tritium pattern the upper waters of the North Pacific can be divided into three regions: a mixed layer that exchanges rapidly with the atmosphere, a laterally ventilated intermediate region (between the mixed layer and at most the winter-outcrop isopy...

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John L. Bullister

National Oceanic and Atmospheric Administration

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Tangdong Qu

University of Hawaii at Manoa

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