Description of AFES 2: Improvements for High-Resolution and Coupled Simulations

Enomoto, Takeshi; Kuwano-Yoshida, Akira; Komori, Nobumasa; Ohfuchi, Wataru

doi:10.1007/978-0-387-49791-4_5

Cited by 68 publications

(73 citation statements)

References 24 publications

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“…We use the AGCM for the Earth Simulator (AFES), version 3 (Ohfuchi et al 2004;Enomoto et al 2008;Kuwano-Yoshida et al 2010a), which has been developed by the Earth Simulator Center and Application Laboratory of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). The horizontal resolution is spectral T239, corresponding to an approximately 50-km interval, with 48 sigma levels in the vertical from the surface to approximately 3 hPa.…”

Section: Model Experiments Configuration and Methodsmentioning

confidence: 99%

Storm-Track Response to SST Fronts in the Northwestern Pacific Region in an AGCM

2017

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The storm-track response to sea surface temperature (SST) fronts in the northwestern Pacific region is investigated using an atmospheric general circulation model with a 50-km horizontal resolution. The following two experiments are conducted: one with 0.258 daily SST data (CNTL) and the other with smoothed SSTs over an area covering SST fronts associated with the Kuroshio, the Kuroshio Extension, the Oyashio, and the subpolar front (SMTHK). The storm track estimated from the local deepening rate of surface pressure (LDR) exhibits a prominent peak in this region in CNTL in January, whereas the storm-track peak weakens and moves eastward in SMTHK. Storm-track differences between CNTL and SMTHK are only found in explosive deepening events with LDR larger than 1 hPa h 21. A diagnostic equation of LDR suggests that latent heat release associated with large-scale condensation contributes to the storm-track enhancement. The SST fronts also affect the large-scale atmospheric circulation over the northeastern Pacific Ocean. The jet stream in the upper troposphere tends to meander northward, which is associated with positive sea level pressure (SLP) anomalies in CNTL, whereas the jet stream flows zonally in SMTHK. A composite analysis for the northwestern Pacific SLP anomaly suggests that frequent explosive cyclone development in the northwestern Pacific in CNTL causes downstream positive SLP anomalies over the Gulf of Alaska. Cyclones in SMTHK developing over the northeastern Pacific enhance the moisture flux along the west coast of North America, increasing precipitation in that region.

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Section: Model Experiments Configuration and Methodsmentioning

confidence: 99%

Storm-Track Response to SST Fronts in the Northwestern Pacific Region in an AGCM

2017

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“…The model data to be analyzed are from the atmospheric general circulation model for the Earth Simulator (AFES) version 3 [Ohfuchi et al, 2004;Enomoto et al, 2008;Kuwano-Yoshida et al, 2010b] developed at the Earth Simulator Center, Japan Agency for Marine Earth Science and Technology. The horizontal resolution is T239, about 59 km in grid spacing, with 48 scaled pressure levels in the vertical.…”

Section: Model Data Setmentioning

confidence: 99%

The atmospheric frontal response to SST perturbations in the Gulf Stream region

Parfitt

Czaja

Minobe

et al. 2016

Geophysical Research Letters

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101

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The link between sea surface temperature (SST) gradients and atmospheric fronts is explored in a general circulation model across the Gulf Stream (GS) region from December to February 1981–2000. Two model experiments are analyzed, one with a realistic control SST distribution and one with a spatially smoothed SST distribution. The analysis shows a noticeable change in regional atmospheric frontal frequency between the two experiments (up to 30%), with the distribution of change exhibiting a clear imprint of the GS SST front. Further analysis of the surface sensible heat flux gradient across cold fronts reveals the pattern of change to be mediated by a thermal interaction between the oceanic and atmospheric fronts (“thermal damping and strengthening”). These results not only emphasize the significance of the GS SST gradient for storm development in the North Atlantic but also highlight the importance of resolution in assessing the role of frontal air‐sea interaction in midlatitude climate variability.

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“…The ALERA dataset was generated by an analysis cycle using a 40-member ensemble forecast with AFES 2.2 (Enomoto et al 2006) at a T159/L48 resolution for the period from May 2005 to October 2006. The assimilated observations are adapted from the operational numerical weather prediction system of the Japan Meteorological Agency (JMA).…”

Section: Alera Datasetmentioning

confidence: 99%

The Impact of the Assimilation of Dropsonde Observations during PALAU2005 in ALERA

Moteki

Shirooka

Yoneyama

et al. 2007

SOLA

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The effect of the assimilation of dropsonde data over the tropical western Pacific was investigated in an objective analysis. In June 2005, 30 dropsondes were released on four separate flight days. The data impact was assessed using the objective analysis dataset of "ALERA." The analysis of the zonal wind field over the tropical western Pacific in ALERA revealed large errors corresponding to active convection. These errors were reduced by 1 3 m s 1 due to the assimilation of the dropsondes. The impact signal due to the assimilation of the dropsondes propagated northward and appeared significantly around Japan. The phase and group speeds of the impact signal at 700 hPa were approximately 3 m s 1 and 12 m s 1 , respectively. The former speed was consistent with the mean meridional wind speed, and the latter speed roughly corresponded to the meridional group speed of Rossby waves with wavelengths of a few thousand kilometers.

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Description of AFES 2: Improvements for High-Resolution and Coupled Simulations

Cited by 68 publications

References 24 publications

Storm-Track Response to SST Fronts in the Northwestern Pacific Region in an AGCM

Storm-Track Response to SST Fronts in the Northwestern Pacific Region in an AGCM

The atmospheric frontal response to SST perturbations in the Gulf Stream region

The Impact of the Assimilation of Dropsonde Observations during PALAU2005 in ALERA

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