scholarly journals An assessment of buoy-derived and numerical weather prediction surface heat fluxes in the tropical Pacific

2006 ◽  
Vol 111 (C6) ◽  
Author(s):  
Meghan F. Cronin ◽  
Christopher W. Fairall ◽  
Michael J. McPhaden
Keyword(s):  
Numerical Weather Prediction ◽  
Weather Prediction ◽  
Tropical Pacific ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Surface Heat Fluxes ◽  
Numerical Weather ◽  
The Tropical Pacific

GFDL's CM2 Global Coupled Climate Models. Part III: Tropical Pacific Climate and ENSO

2006 ◽  
Vol 19 (5) ◽  
pp. 698-722 ◽  
Author(s):  
Andrew T. Wittenberg ◽  
Anthony Rosati ◽  
Ngar-Cheung Lau ◽  
Jeffrey J. Ploshay
Keyword(s):  
Thermal Structure ◽  
Tropical Pacific ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Geophysical Fluid Dynamics Laboratory ◽  
Trade Winds ◽  
Equatorial Undercurrent ◽  
Surface Heat Fluxes ◽  
Zonal Winds ◽  
Sst Anomalies

Abstract Multicentury integrations from two global coupled ocean–atmosphere–land–ice models [Climate Model versions 2.0 (CM2.0) and 2.1 (CM2.1), developed at the Geophysical Fluid Dynamics Laboratory] are described in terms of their tropical Pacific climate and El Niño–Southern Oscillation (ENSO). The integrations are run without flux adjustments and provide generally realistic simulations of tropical Pacific climate. The observed annual-mean trade winds and precipitation, sea surface temperature, surface heat fluxes, surface currents, Equatorial Undercurrent, and subsurface thermal structure are well captured by the models. Some biases are evident, including a cold SST bias along the equator, a warm bias along the coast of South America, and a westward extension of the trade winds relative to observations. Along the equator, the models exhibit a robust, westward-propagating annual cycle of SST and zonal winds. During boreal spring, excessive rainfall south of the equator is linked to an unrealistic reversal of the simulated meridional winds in the east, and a stronger-than-observed semiannual signal is evident in the zonal winds and Equatorial Undercurrent. Both CM2.0 and CM2.1 have a robust ENSO with multidecadal fluctuations in amplitude, an irregular period between 2 and 5 yr, and a distribution of SST anomalies that is skewed toward warm events as observed. The evolution of subsurface temperature and current anomalies is also quite realistic. However, the simulated SST anomalies are too strong, too weakly damped by surface heat fluxes, and not as clearly phase locked to the end of the calendar year as in observations. The simulated patterns of tropical Pacific SST, wind stress, and precipitation variability are displaced 20°–30° west of the observed patterns, as are the simulated ENSO teleconnections to wintertime 200-hPa heights over Canada and the northeastern Pacific Ocean. Despite this, the impacts of ENSO on summertime and wintertime precipitation outside the tropical Pacific appear to be well simulated. Impacts of the annual-mean biases on the simulated variability are discussed.

scholarly journals The Impact of Satellite Winds and Latent Heat Fluxes in a Numerical Simulation of the Tropical Pacific Ocean

2006 ◽  
Vol 19 (22) ◽  
pp. 5889-5902 ◽  
Author(s):  
Ludos-Herve Ayina ◽  
Abderrahim Bentamy ◽  
Alberto M. Mestas-Nuñez ◽  
Gurvan Madec
Keyword(s):  
Pacific Ocean ◽  
Latent Heat ◽  
Weather Prediction ◽  
Turbulent Fluxes ◽  
Tropical Pacific ◽  
Heat Fluxes ◽  
Tropical Pacific Ocean ◽  
Equatorial Pacific Ocean ◽  
The Impact ◽  
The Tropical Pacific

Abstract Several oceanic operational programs use remotely sensed fluxes to complement atmospheric operational analyses from major national weather prediction centers. The main goal of this study is to evaluate the ability of the ocean model (ORCA) to correctly simulate the dynamic of the tropical Pacific Ocean in 1996–98 when forced by the satellite turbulent fluxes (wind stress and latent heat fluxes). The results are compared with the oceanic response resulting from forcing the model with the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis. Three sensitivity simulations forced with satellite and atmospheric analysis fields are performed. The control experiment is forced with the ECMWF fluxes. The solutions of these simulations are compared with data from the Tropical Atmosphere–Ocean (TAO) buoys and from sea surface temperatures analysis by Reynolds and Smith in the equatorial Pacific Ocean. The analysis results indicate that the model reproduces well the major spatial and temporal oceanic structures including the main characteristics of the 1997–98 El Niño. More specifically, the comparisons with buoys indicate that the experiment forced by the winds and the satellite latent heat fluxes is closer to the observations. They provide weak rms difference and strong correlations along the whole 500-m depth column. Furthermore, the correlations with the SST analysis vary between 75% and 95% compared to 65% and 77% for the experiment forced by ECMWF fluxes. The currents in the first 350 m also show a strong sensitivity to satellite turbulent fluxes.

scholarly journals Optimizing Mooring Placement to Constrain Southern Ocean Air–Sea Fluxes

2020 ◽  
Vol 37 (8) ◽  
pp. 1365-1385
Author(s):  
Yanzhou Wei ◽  
Sarah T. Gille ◽  
Matthew R. Mazloff ◽  
Veronica Tamsitt ◽  
Sebastiaan Swart ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Numerical Weather Prediction ◽  
High Frequency ◽  
Weather Prediction ◽  
Low Frequency ◽  
Heat Fluxes ◽  
Test Case ◽  
Numerical Weather ◽  
Ocean Observing

AbstractProposals from multiple nations to deploy air–sea flux moorings in the Southern Ocean have raised the question of how to optimize the placement of these moorings in order to maximize their utility, both as contributors to the network of observations assimilated in numerical weather prediction and also as a means to study a broad range of processes driving air–sea fluxes. This study, developed as a contribution to the Southern Ocean Observing System (SOOS), proposes criteria that can be used to determine mooring siting to obtain best estimates of net air–sea heat flux (Qnet). Flux moorings are envisioned as one component of a multiplatform observing system, providing valuable in situ point time series measurements to be used alongside satellite data and observations from autonomous platforms and ships. Assimilating models (e.g., numerical weather prediction and reanalysis products) then offer the ability to synthesize the observing system and map properties between observations. This paper develops a framework for designing mooring array configurations to maximize the independence and utility of observations. As a test case, within the meridional band from 35° to 65°S we select eight mooring sites optimized to explain the largest fraction of the total variance (and thus to ensure the least variance of residual components) in the area south of 20°S. Results yield different optimal mooring sites for low-frequency interannual heat fluxes compared with higher-frequency subseasonal fluxes. With eight moorings, we could explain a maximum of 24.6% of high-frequency Qnet variability or 44.7% of low-frequency Qnet variability.

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