Investigating the 15 years air-sea flux climatology from the ECMWF re-analysis project as a surface boundary condition for ocean models

Garnier, Elodie; Barnier, Bernard; Siefridt, L.; Béranger, Karine

doi:10.1002/1097-0088(20001130)20:14<1653::aid-joc575>3.0.co;2-g

Cited by 28 publications

(28 citation statements)

References 34 publications

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“…11b), the OHT pattern from Rose and Marshall (2009) shows a local minimum at mid-latitudes where the sea ice edge can stably rest. This OHT structure is closer to the observations (see for example Garnier et al, 2000). Within the improved EBM of Rose and Marshall (2009) caps of various size can persist at polar latitudes.…”

Section: Discussionsupporting

confidence: 87%

Effect of the Ordovician paleogeography on the (in)stability of the climate

et al. 2014

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Abstract. The Ordovician Period (485-443 Ma) is characterized by abundant evidence for continental-sized ice sheets. Modeling studies published so far require a sharp CO 2 drawdown to initiate this glaciation. They mostly used nondynamic slab mixed-layer ocean models. Here, we use a general circulation model with coupled components for ocean, atmosphere, and sea ice to examine the response of Ordovician climate to changes in CO 2 and paleogeography. We conduct experiments for a wide range of CO 2 (from 16 to 2 times the preindustrial atmospheric CO 2 level (PAL)) and for two continental configurations (at 470 and at 450 Ma) mimicking the Middle and the Late Ordovician conditions. We find that the temperature-CO 2 relationship is highly non-linear when ocean dynamics are taken into account. Two climatic modes are simulated as radiative forcing decreases. For high CO 2 concentrations (≥ 12 PAL at 470 Ma and ≥ 8 PAL at 450 Ma), a relative hot climate with no sea ice characterizes the warm mode. When CO 2 is decreased to 8 PAL and 6 PAL at 470 and 450 Ma, a tipping point is crossed and climate abruptly enters a runaway icehouse leading to a cold mode marked by the extension of the sea ice cover down to the midlatitudes. At 450 Ma, the transition from the warm to the cold mode is reached for a decrease in atmospheric CO 2 from 8 to 6 PAL and induces a ∼ 9 • C global cooling. We show that the tipping point is due to the existence of a 95 % oceanic Northern Hemisphere, which in turn induces a minimum in oceanic heat transport located around 40 • N. The latter allows sea ice to stabilize at these latitudes, explaining the potential existence of the warm and of the cold climatic modes. This major climatic instability potentially brings a new explanation to the sudden Late Ordovician Hirnantian glacial pulse that does not require any large CO 2 drawdown.

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Section: Discussionsupporting

confidence: 87%

Effect of the Ordovician paleogeography on the (in)stability of the climate

et al. 2014

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“…4d) appears to agree reasonably well with observed estimates and the general pattern is close to that inferred from NCEP and ECMWF re-analysis (Garnier et al 2000;Trenberth and Caron 2001). In the observed estimates inferred from NCEP and ECMWF re-analysis, the maximum northward heat transport is slightly over 1.5 PW (PW = 10 15 W) at around 15 o N, which is comprised of 1 PW from the Atlantic Ocean and 0.5 PW from the Pacific Ocean (Garnier et al 2000;Trenberth and Caron . These estimates are consistent with the simulated meridional heat transport.…”

Section: Reference Experimentssupporting

confidence: 81%

Ocean Response to the Pinatubo and 1259 Volcanic Eruptions

Kim¹,

Kim²

2012

Ocean and Polar Research

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: The ocean's response to the Pinatubo and 1259 volcanic eruptions was investigated using an ocean general circulation model equipped with an energy balance model. Volcanic eruptions release gases into the atmosphere which increases the aerosol optical depth and acts to reduce the incoming short-wave radiation. For example, there was a huge volcanic eruption (Pinatubo) in 1991 which reduced the global mean radiative forcing by about 3 W m −2 . Two numerical experiments were simulated. The first experiment features the Pinatubo eruption and the second experiment simulates the much larger volcanic eruption that occurred in 1259 when the radiative forcing was reduced by 7 times compared to the Pinatubo event. With the reduced radiative forcing due to the Pinatubo eruption at about 3 W m −2 and 1259 eruption at about 21 W m −2 , the global mean sea surface temperature (SST) decreased to its lowest in the second year after each event by about 0.4 o C and 1.6 o C, respectively. Sea surface salinity (SSS) increased substantially in the northern North Pacific, northern North Atlantic, and the Southern Ocean. The reduced SST together with SSS increased ocean convection, which yielded an increase in North Atlantic Deep Water, Antarctic Bottom Water, and North Pacific Intermediate Water production and their outflows. The increase in overturning circulation eventually increased the pole-ward ocean heat fluxes. In conclusion, huge volcanic eruptions perturb the ocean substantially and their hallmarks last for more than a decade, confirming the importance of volcanic eruptions in illustrating the decadal-climate variability recorded in the paleoclimate proxy data for the past million years.

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“…The vertical resolution comprises 43 levels spaced from 12 m at the surface to 200 m below 1500 m. The bathymetry is calculated by bilinear interpolation of the Smith and Sandwell (1997) dataset. Northern and southern boundaries are closed, and the model is restored to the climatology of Reynaud et al (1998) (Garnier et al 2000). Surface heat flux is formulated based on Barnier et al (1995).…”

Section: B Embedded Systemmentioning

confidence: 99%

Mesoscale Eddies in the Labrador Sea and Their Contribution to Convection and Restratification

Chanut

Barnier

Large

et al. 2008

Journal of Physical Oceanography

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133

194

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International audienceThe cycle of open ocean deep convection in the Labrador Sea is studied in a realistic, high-resolution (4 km) regional model, embedded in a coarser (⅓°) North Atlantic setup. This configuration allows the simultaneous generation and evolution of three different eddy types that are distinguished by their source region, generation mechanism, and dynamics. Very energetic Irminger Rings (IRs) are generated by barotropic instability of the West Greenland and Irminger Currents (WGC/IC) off Cape Desolation and are characterized by a warm, salty subsurface core. They densely populate the basin north of 58°N, where their eddy kinetic energy (EKE) matches the signal observed by satellite altimetry. Significant levels of EKE are also found offshore of the West Greenland and Labrador coasts, where boundary current eddies (BCEs) are spawned by weakly energetic instabilities all along the boundary current system (BCS). Baroclinic instability of the steep isopycnal slopes that result from a deep convective overturning event produces convective eddies (CEs) of 20-30 km in diameter, as observed and produced in more idealized models, with a distinct seasonal cycle of EKE peaking in April. Sensitivity experiments show that each of these eddy types plays a distinct role in the heat budget of the central Labrador Sea, hence in the convection cycle. As observed in nature, deep convective mixing is limited to areas where adequate preconditioning can occur, that is, to a small region in the southwestern quadrant of the central basin. To the east, west, and south, BCEs flux heat from the BCS at a rate sufficient to counteract air-sea buoyancy loss. To the north, this eddy flux alone is not enough, but when combined with the effects of Irminger Rings, preconditioning is effectively inhibited here too. Following a deep convective mixing event, the homogeneous convection patch reaches as deep as 2000 m and a horizontal scale on the order of 200 km, as has been observed. Both CEs and BCEs are found to play critical roles in the lateral mixing phase, when the patch restratifies and transforms into Labrador Sea Water (LSW). BCEs extract the necessary heat from the BCS and transport it to the deep convection site, where it fluxed into convective patches by CEs during the initial phase. Later in the phase, BCE heat flux maintains and strengthens the restratification throughout the column, while solar heating establishes a near-surface seasonal stratification. In contrast, IRs appear to rarely enter the deep convection region. However, by virtue of their control on the surface area preconditioned for deep convection and the interannual variability of the associated barotropic instability, they could have an important role in the variability of LSW

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Investigating the 15 years air-sea flux climatology from the ECMWF re-analysis project as a surface boundary condition for ocean models

Cited by 28 publications

References 34 publications

Effect of the Ordovician paleogeography on the (in)stability of the climate

Effect of the Ordovician paleogeography on the (in)stability of the climate

Ocean Response to the Pinatubo and 1259 Volcanic Eruptions

Mesoscale Eddies in the Labrador Sea and Their Contribution to Convection and Restratification

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