Evaluation of FIO-ESM v1.0 Seasonal Prediction Skills Over the North Pacific

2021 ◽  
Author(s):  
Yajuan Song ◽  
Xunqiang Yin
Keyword(s):  
Data Assimilation ◽  
North Pacific ◽  
Climate Model ◽  
Initial Conditions ◽  
Coupled Model ◽  
Seasonal Prediction ◽  
Optimal Interpolation ◽  
The North ◽  
Prediction Systems ◽  
The North Pacific

<p>Accurate prediction over the North Pacific, especially for the key parameter of sea<br>surface temperature (SST), remains a challenge for short-term climate prediction. In<br>this study, seasonal predicted skills of the First Institute of Oceanography Earth System<br>Model version 1.0 (FIO-ESM v1.0) over the North Pacific were assessed. Ensemble<br>adjustment Kalman filter (EAKF) and Projection Optimal Interpolation (Projection-OI) data<br>assimilation schemes were used to provide initial conditions for FIO-ESM v1.0 hindcasts<br>that were started from the first day of each month between 1993 and 2017. Evolution<br>and spacial distribution of SST anomalies over the North Pacific were reasonably<br>reproduced in EAKF and Projection-OI assimilation output. Two hindcast experiments<br>show that the skill of FIO-ESM v1.0 with the EAKF data assimilation scheme to predict<br>SST over the North Pacific is considerably higher than that with Projection-OI data<br>assimilation for all lead times of 1–6 months, especially in the central North Pacific where<br>the subsurface ocean temperature in the initial conditions is significantly improved by<br>EAKF data assimilation. For the Kuroshio–Oyashio extension (KOE) region, the errors<br>in the initial conditions have more rapid propagation resulting in large discrepancies<br>between simulated and observed values, which are reduced by inducing surface<br>waves into the climate model. Incorporation of realistic initial conditions and reasonable<br>physical processes into the coupled model is essential to improving seasonal prediction<br>skill. These results provide a solid basis for the development of operational seasonal<br>prediction systems for the North Pacific.</p>

scholarly journals Seasonal Prediction of North Pacific SSTs and PDO in the NCEP CFS Hindcasts

2012 ◽  
Vol 25 (17) ◽  
pp. 5689-5710 ◽  
Author(s):  
Caihong Wen ◽  
Yan Xue ◽  
Arun Kumar
Keyword(s):  
North Pacific ◽  
Initial Conditions ◽  
Southern Oscillation ◽  
Signal To Noise Ratio ◽  
Seasonal Prediction ◽  
Prediction Skill ◽  
The North ◽  
The Impact ◽  
The North Pacific ◽  
Central North Pacific

Abstract Seasonal prediction skill of North Pacific sea surface temperature anomalies (SSTAs) and the Pacific decadal oscillation (PDO) in the NCEP Climate Forecast System (CFS) retrospective forecasts is assessed. The SST forecasts exhibit significant skills over much of the North Pacific for two seasons in advance and outperform persistence over much of the North Pacific except near the Kuroshio–Oyashia Extension. Similar to the “spring barrier” feature in the El Niño–Southern Oscillation forecasts, the central North Pacific SST experiences a faster drop in prediction skill for forecasts initialized from November to February than those from May to August. Forecasts for the PDO displayed a constant phase shift from the observation with respect to lead time. The PDO skill has a clear seasonality with highest skill for forecasts initialized in boreal spring. The impact of ENSO on the PDO and North Pacific SST prediction was investigated. The analysis revealed that seasonal prediction skill in the central North Pacific mainly results from the skillful prediction of ENSO. As a result, the PDO is more skillful than persistence at all lead times during ENSO years. On the other hand, persistence is superior to the CFS forecast during ENSO-neutral conditions owing to errors in initial conditions and deficiencies in model physics. Examination of seasonal variance and predictability (signal-to-noise ratio) further articulates the influence of ENSO on the PDO skill. The results suggest that improvement of ENSO prediction as well as reduction in model biases in the western North Pacific will lead to improvements in the PDO and North Pacific SST predictions.

scholarly journals Effects of the 18.6-yr Modulation of Tidal Mixing on the North Pacific Bidecadal Climate Variability in a Coupled Climate Model

2012 ◽  
Vol 25 (21) ◽  
pp. 7625-7642 ◽  
Author(s):  
Yuki Tanaka ◽  
Ichiro Yasuda ◽  
Hiroyasu Hasumi ◽  
Hiroaki Tatebe ◽  
Satoshi Osafune
Keyword(s):  
Climate Variability ◽  
North Pacific ◽  
Climate Model ◽  
Tidal Mixing ◽  
Global Ocean ◽  
Coupled Climate Model ◽  
Orbital Inclination ◽  
The North ◽  
Sst Anomaly ◽  
The North Pacific

Diapycnal mixing induced by tide–topography interaction, one of the essential factors maintaining the global ocean circulation and hence the global climate, is modulated by the 18.6-yr period oscillation of the lunar orbital inclination, and has therefore been hypothesized to influence bidecadal climate variability. In this study, the spatial distribution of diapycnal diffusivity together with its 18.6-yr oscillation estimated from a global tide model is incorporated into a state-of-the-art numerical coupled climate model to investigate its effects on climate variability over the North Pacific and to understand the underlying physical mechanism. It is shown that a significant sea surface temperature (SST) anomaly with a period of 18.6 years appears in the Kuroshio–Oyashio Extension region; a positive (negative) SST anomaly tends to occur during strong (weak) tidal mixing. This is first induced by anomalous horizontal circulation localized around the Kuril Straits, where enhanced modulation of tidal mixing exists, and then amplified through a positive feedback due to midlatitude air–sea interactions. The resulting SST and sea level pressure variability patterns are reminiscent of those associated with one of the most prominent modes of climate variability in the North Pacific known as the Pacific decadal oscillation, suggesting the potential for improving climate predictability by taking into account the 18.6-yr modulation of tidal mixing.

A New Look at Snowpack Trends in the Cascade Mountains

2010 ◽  
Vol 23 (10) ◽  
pp. 2473-2491 ◽  
Author(s):  
Mark T. Stoelinga ◽  
Mark D. Albright ◽  
Clifford F. Mass
Keyword(s):  
Time Series ◽  
Global Warming ◽  
Pacific Northwest ◽  
North Pacific ◽  
Climate Model ◽  
North Pacific Ocean ◽  
Tropospheric Temperature ◽  
Anthropogenic Global Warming ◽  
The North ◽  
The North Pacific

Abstract This study examines the changes in Cascade Mountain spring snowpack since 1930. Three new time series facilitate this analysis: a water-balance estimate of Cascade snowpack from 1930 to 2007 that extends the observational record 20 years earlier than standard snowpack measurements; a radiosonde-based time series of lower-tropospheric temperature during onshore flow, to which Cascade snowpack is well correlated; and a new index of the North Pacific sea level pressure pattern that encapsulates modes of variability to which Cascade spring snowpack is particularly sensitive. Cascade spring snowpack declined 23% during 1930–2007. This loss is nearly statistically significant at the 5% level. The snowpack increased 19% during the recent period of most rapid global warming (1976–2007), though this change is not statistically significant because of large annual variability. From 1950 to 1997, a large and statistically significant decline of 48% occurred. However, 80% of this decline is connected to changes in the circulation patterns over the North Pacific Ocean that vary naturally on annual to interdecadal time scales. The residual time series of Cascade snowpack after Pacific variability is removed displays a relatively steady loss rate of 2.0% decade−1, yielding a loss of 16% from 1930 to 2007. This loss is very nearly statistically significant and includes the possible impacts of anthropogenic global warming. The dates of maximum snowpack and 90% melt out have shifted 5 days earlier since 1930. Both shifts are statistically insignificant. A new estimate of the sensitivity of Cascade spring snowpack to temperature of −11% per °C, when combined with climate model projections of 850-hPa temperatures offshore of the Pacific Northwest, yields a projected 9% loss of Cascade spring snowpack due to anthropogenic global warming between 1985 and 2025.

Model Biases in the Simulation of the Springtime North Pacific ENSO Teleconnection

2020 ◽  
Vol 33 (23) ◽  
pp. 9985-10002
Author(s):  
Ruyan Chen ◽  
Isla R. Simpson ◽  
Clara Deser ◽  
Bin Wang
Keyword(s):  
El Niño ◽  
North Pacific ◽  
Climate Models ◽  
El Nino ◽  
Coupled Model ◽  
La Niña ◽  
Late Winter ◽  
The North ◽  
La Nina ◽  
The North Pacific

AbstractThe wintertime ENSO teleconnection over the North Pacific region consists of an intensified (weakened) low pressure center during El Niño (La Niña) events both in observations and in climate models. Here, it is demonstrated that this teleconnection persists too strongly into late winter and spring in the Community Earth System Model (CESM). This discrepancy arises in both fully coupled and atmosphere-only configurations, when observed SSTs are specified, and is shown to be robust when accounting for the sampling uncertainty due to internal variability. Furthermore, a similar problem is found in many other models from piControl simulations of the Coupled Model Intercomparison Project (23 out of 43 in phase 5 and 11 out of 20 in phase 6). The implications of this bias for the simulation of surface climate anomalies over North America are assessed. The overall effect on the ENSO composite field (El Niño minus La Niña) resembles an overly prolonged influence of ENSO into the spring with anomalously high temperatures over Alaska and western Canada, and wet (dry) biases over California (southwest Canada). Further studies are still needed to disentangle the relative roles played by diabatic heating, background flow, and other possible contributions in determining the overly strong springtime ENSO teleconnection intensity over the North Pacific.

scholarly journals Importance of Resolving Kuroshio Front and Eddy Influence in Simulating the North Pacific Storm Track

2017 ◽  
Vol 30 (5) ◽  
pp. 1861-1880 ◽  
Author(s):  
Xiaohui Ma ◽  
Ping Chang ◽  
R. Saravanan ◽  
Raffaele Montuoro ◽  
Hisashi Nakamura ◽  
...  
Keyword(s):  
North Pacific ◽  
Large Scale ◽  
Climate Model ◽  
Kuroshio Extension ◽  
Storm Track ◽  
Small Scale ◽  
Low Resolution ◽  
The North ◽  
The North Pacific ◽  
Sst Anomalies

Abstract Local and remote atmospheric responses to mesoscale SST anomalies associated with the oceanic front and eddies in the Kuroshio Extension region (KER) are studied using high- (27 km) and low-resolution (162 km) regional climate model simulations in the North Pacific. In the high-resolution simulations, removal of mesoscale SST anomalies in the KER leads to not only a local reduction in cyclogenesis but also a remote large-scale equivalent barotropic response with a southward shift of the downstream storm track and jet stream in the eastern North Pacific. In the low-resolution simulations, no such significant remote response is found when mesoscale SST anomalies are removed. The difference between the high- and low-resolution model simulated atmospheric responses is attributed to the effect of mesoscale SST variability on cyclogenesis through moist baroclinic instability. It is only when the model has sufficient resolution to resolve small-scale diabatic heating that the full effect of mesoscale SST forcing on the storm track can be correctly simulated.

scholarly journals Modulation of Atmospheric Response to North Pacific SST Anomalies under Global Warming: A Statistical Assessment

2012 ◽  
Vol 25 (19) ◽  
pp. 6554-6566 ◽  
Author(s):  
Bolan Gan ◽  
Lixin Wu
Keyword(s):  
Global Warming ◽  
North Pacific ◽  
Climate Model ◽  
Storm Track ◽  
Early Winter ◽  
The North ◽  
Basin Scale ◽  
Climate Model Simulations ◽  
The North Pacific ◽  
Sst Anomalies

Abstract In this study the modulation of ocean-to-atmosphere feedback over the North Pacific in early winter from global warming is investigated based on both the observations and multiple climate model simulations from a statistical perspective. It is demonstrated that the basin-scale atmospheric circulation displays an equivalent barotropic ridge in response to warm SST anomalies in the Kuroshio–Oyashio Extension (KOE) region. This warm SST–ridge response in early winter can be enhanced significantly by global warming, indicating a strengthening of air–sea coupling over the North Pacific. This enhancement is likely associated with the intensification of storm tracks and, in turn, the amplification of atmospheric transient eddy feedback in a warm climate, although the secular trend of enhanced storm-track activity over the North Pacific is suggested to be biased in reanalysis product.

scholarly journals Coupled impacts of sea ice variability and North Pacific atmospheric circulation on Holocene hydroclimate in Arctic Alaska

2020 ◽  
Vol 117 (52) ◽  
pp. 33034-33042
Author(s):  
Ellie Broadman ◽  
Darrell S. Kaufman ◽  
Andrew C. G. Henderson ◽  
Irene Malmierca-Vallet ◽  
Melanie J. Leng ◽  
...  
Keyword(s):  
Sea Ice ◽  
North Pacific ◽  
Regional Climate ◽  
Coupled Model ◽  
The Arctic ◽  
Bering Strait ◽  
Aleutian Low ◽  
The North ◽  
Arctic Alaska ◽  
The North Pacific

Arctic Alaska lies at a climatological crossroads between the Arctic and North Pacific Oceans. The modern hydroclimate of the region is responding to rapidly diminishing sea ice, driven in part by changes in heat flux from the North Pacific. Paleoclimate reconstructions have improved our knowledge of Alaska’s hydroclimate, but no studies have examined Holocene sea ice, moisture, and ocean−atmosphere circulation in Arctic Alaska, limiting our understanding of the relationship between these phenomena in the past. Here we present a sedimentary diatom assemblage and diatom isotope dataset from Schrader Pond, located ∼80 km from the Arctic Ocean, which we interpret alongside synthesized regional records of Holocene hydroclimate and sea ice reduction scenarios modeled by the Hadley Centre Coupled Model Version 3 (HadCM3). The paleodata synthesis and model simulations suggest the Early and Middle Holocene in Arctic Alaska were characterized by less sea ice, a greater contribution of isotopically heavy Arctic-derived moisture, and wetter climate. In the Late Holocene, sea ice expanded and regional climate became drier. This climatic transition is coincident with a documented shift in North Pacific circulation involving the Aleutian Low at ∼4 ka, suggesting a Holocene teleconnection between the North Pacific and Arctic. The HadCM3 simulations reveal that reduced sea ice leads to a strengthened Aleutian Low shifted west, potentially increasing transport of warm North Pacific water to the Arctic through the Bering Strait. Our findings demonstrate the interconnectedness of the Arctic and North Pacific on multimillennial timescales, and are consistent with future projections of less sea ice and more precipitation in Arctic Alaska.

scholarly journals Investigating the Role of Ocean–Atmosphere Coupling in the North Pacific Ocean

2014 ◽  
Vol 27 (2) ◽  
pp. 592-606 ◽  
Author(s):  
Dimitry Smirnov ◽  
Matthew Newman ◽  
Michael A. Alexander
Keyword(s):  
North Pacific ◽  
Climate Model ◽  
North Pacific Ocean ◽  
Global Climate Model ◽  
The North ◽  
Sst Variability ◽  
Oceanic Forcing ◽  
Noise Forcing ◽  
The Kuroshio ◽  
The North Pacific

Abstract Air–sea interaction over the North Pacific is diagnosed using a simple, local coupled autoregressive model constructed from observed 7-day running-mean sea surface temperature (SST) and 2-m air temperature TA anomalies during the extended winter from the 1° × 1° objectively analyzed air–sea fluxes (OAFlux) dataset. Though the model is constructed from 1-week lag statistics, it successfully reproduces the observed anomaly evolution through lead times of 90 days, allowing an estimation of the relative roles of coupling and internal atmospheric and oceanic forcing upon North Pacific SSTs. It is found that east of the date line, SST variability is maintained by, but has little effect on, TA variability. However, in the Kuroshio–Oyashio confluence and extension region, about half of the SST variability is independent of TA, driven instead by SST noise forcing internal to the ocean. Including surface zonal winds in the analysis does not alter this conclusion, suggesting TA adequately represents the atmosphere. Repeating the analysis with the output of two control simulations from a fully coupled global climate model (GCM) differing only in their ocean resolution yields qualitatively similar results. However, for the simulation employing the coarse-resolution (1°) ocean model, all SST variability depends upon TA, apparently caused by a near absence of ocean-induced noise forcing. Collectively, these results imply that a strong contribution from internal oceanic forcing drives SST variability in the Kuroshio–Oyashio region, which may be used as a justification for atmospheric GCM experiments forced with SST anomalies in that region alone. This conclusion is unaffected by increasing the dimensionality of the model to allow for intrabasin interaction.

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