Stephen E. Pazan

Short-Term Climatic Variability in the Thermal Structure of the Pacific Ocean during 1979–82

Abstract Short-term climatic variability in both sea surface temperature (SST) and vertically averaged temperature over the upper 400 m of ocean (Tav) is mapped over the Pacific from 20°S to 50°N each bimonth for four years from 1979 to 1982, leading up to the 1982–83 ENSO (El Nino–Southern Oscillation) event. This mapping was made possible by the collection of approximately 85 000 temperature/depth observations in the Pacific Ocean by volunteer observing ships. Anomalies of SST and Tav were approximately the same magnitude at midlatitude as in the tropics, with the exception of large changes occurring in the tropics during the 1982–83 ENSO event. During the ENSO event, (Tav variability was largest in the western tropical North Pacific and SST variability was largest in the eastern equatorial Pacific. Both parameters had spatial patterns which were of opposite phase on either side of the ocean, indicating an eastward shift of warm waters during the ENSO event. Correlation studies determined that on averag...

Hindcast/forecast of ENSO events based upon the redistribution of observed and model heat content in the Western Tropical Pacific, 1964-86

Anomalous sea level, anomalous observed dynamic height (0/400 db) and anomalous model dynamic height are examined at the locations of 13 island sea level stations in the tropical Pacific for each bimonth of the four year period 1979 to 1982. Starting in 1981, the anomalous dynamic height data show off-equatorial Rossby waves propagated toward the W boundary of the Pacific basin. At the W boundary, the model Rossby wave activity was found to have excited coastally trapped Kelvin-Munk waves which transmitted the anomalous dynamic height equatorward. At the equator, coastally trapped wave activity excited eastward propagating equatorial Kelvin waves, yielding a pair of anomalous peaks in dynamic height variability in the E equatorial Pacific associated with the 1982–1983 ENSO event. The evolution of the peaks in dynamic height associated with the Rossby and Kelvin wave activity reflects the redistribution of observed upper-ocean heat content in the W tropical Pacific, providing a qualitative hindcast for the 1982–1983 ENSO event.

Off-Equatorial Westward Propagating Rossby Waves in the Tropical Pacific during the 1982–83 and 1986–87 ENSO Events

Abstract Analysis of anomalous vertically averaged temperatures (TAV) in the tropical Pacific Ocean for the eight-year period 1979-86, finds the development during the onset phase, one to two years before the mature phase of the two ENSO events of the period, having dynamically significant similarities both north and south of the equator. During the onset phase of both ENSO events, each beginning in the off-equatorial western tropical Pacific (about 10° latitude), positive anomalies of TAV occurred during northern autumn/winter, one year prior to the mature phase of each ENSO event, in both Northern and Southern hemispheres. This corroborates model results of Pazan et al. and supports the hindcasting/forecasting capability of ENSO events obtained by White et al., though the latter considered only the Northern Hemisphere. It is also demonstrated that the development of positive TAV anomalies in northern autumn/winter along the tropical maritime western boundary of both hemispheres was associated with wind-...

New global drifter data set available

Since 1978, oceanographers, meteorologists, and the U.S. Navy have deployed a large number of Argos satellite-tracked drifters in all of the major ocean basins (Table l). The Data Buoy Cooperation Panel (DBCP) of the World Meteorological Organization/Intergovernmental Oceanographic Commission (WMO/IOC) has coordinated the deployment of drifters via cooperative projects in various ocean basins. In any given month since 1993, there has been an array of more than 600 drifters in the global ocean (http://www.aoml.noaa.gov/phod/dac/ dacdata.html). Most of the raw observations and processed data have been accumulating at the Meteorological and Environmental Data Service (MEDS), Canada. The raw data on file have been processed from MEDS, and other sources, and merged with the processed data at the Atlantic Oceanographic and Meteorological Laboratory (AOML) to form a single file.

Processes of Short-Term Climatic Variability in the Baroclinic Structure of the Interior Western Tropical North Pacific

Abstract A realistic simulation of short-term climatic variability in the relative dynamic height of the interior western tropical North Pacific (4°–22°N, 127°E–180°) for 9 years (1966–74) was conducted using a two-layer, wind-driven, baroclinic long-wave model. Results of this model were compared with bimonthly maps of observed dynamic height (0/400 db) for the region, constructed by White and Hasunuma from all available temperature/depth observations for the same period. The interannual rms differences about the mean annual cycle of the model dynamic height had a spatial pattern over the region of interest that was nearly identical to that observed, with maximum values (i.e., 3.5 and 4.5 dyn cm, respectively) in the vicinity of the North Equatorial Ridge at 15°N and minimum values (i.e., 2.0 and 3.5 dyn cm, respectively) in the vicinity of the North Equatorial Ridge at 15°N and minimum values (i.e., 2.0 and 3.5 dyn cm, respectively) in the Countercurrent Trough at 7°N. Model frequency spectra were ident...

Joint Environment Data Analysis (JEDA) Center

With the inception of the Tropical Ocean/Global Atmosphere (TOGA) and World Ocean Circulation Experiment (WOCE) global climatic research programs, researchers have recognized an increased need for management of basin-scale, quality-controlled oceanographic data sets. At the same time, they have realized that this can be conducted best through cooperation between government and academia. This has led to the establishment of the Joint Environmental Data Analysis (JEDA) Center by the National Oceanographic Data Center (NODC) of the National Environmental Satellite Data and Information Service (NESDIS) and the Scripps Institution of Oceanography (SIO) of the University of California at San Diego, under the sponsorship of the U.S. TOGA Project Office of the National Ocean and Atmospheric Administration (NOAA) and the National Science Foundation.

Short-Term Climatic Variability in the Volume Budget of the Western Tropical North Pacific Ocean during 1979–82

Abstract Anomalous 14°C isotherm depth and anomalous geostrophic volume transport above the 14°C isotherm depth are calculated in the tropical Pacific for each bimonth of the four year period 1979 to 1982, based on 15 000 temperature/depth observations made by volunteer observing ships. The first two eigenfunctions (EOFs) of the anomalous 14°C isotherm depth, the anomalous zonal geostrophic volume transport, and the anomalous meridional Ekman volume transport explain 44%, 32% and 47% of their variances, respectively. Most of the variability explained by the first EOF is associated with the 1982–83 ENSO event. The EOFs indicate that a loss of anomalous volume above the 14°C isotherm in the western tropical North Pacific is correlated with an increase in anomalous volume in the eastern equatorial Pacific. There is a simultaneous intensification of anomalous eastward geostrophic currents across the width of the equatorial Pacific; however, from 150°E to 140°W there is also a simultaneous intensification of a...