scholarly journals Changing of surface thermal parameters in the Northern Pacific and some possible climatic affects

2021 ◽  
pp. 105-108
Author(s):  
Т.Р. Кильматов ◽  
А.Д. Черепанова
Keyword(s):  
Surface Temperature ◽  
North Pacific Ocean ◽  
Kuroshio Extension ◽  
Winter Season ◽  
Time Step ◽  
Global Circulation ◽  
The North ◽  
Vertical Speed ◽  
One Year ◽  
The One

В работе на основе базы данных температуры поверхности воды в северной части Тихого океана на климатическом масштабе 1980 - 2019 годы с временным шагом один год исследована зависимость скорости изменения температуры от широты. В летний (август) период отмечается устойчивая зависимость темпов роста средней зональной температуры поверхности в направлении от тропиков к субарктике. Характерная скорость роста температуры в тропических широтах 0,011 0C/год, в субтропиках 0,021 0C/год, в субарктических акваториях выше 400N имеем 0,027 0C/год. В зимний сезон (февраль) такой тенденции не наблюдается. Представлены количественные оценки возможного влияния температурных трендов на глобальную циркуляцию. Рост поверхностной температуры увеличивает вертикальную стратификацию и уменьшает вертикальный обмен вод, относительное ослабление вертикальной скорости не превышает 0,01 % за десятилетие, что представляет незначительным. Представлена количественная оценка уменьшения геострофической составляющей горизонтальной скорости течения продолжения Куросио на восток вследствие климатического сглаживания перепада температуры воды южнее и севернее струи. The change of sea surface temperature (SST) in the North Pacific Ocean on the climatic scale 1980 - 2019 is considered. The rate of temperature change as a function of latitude with the one year time step and the 10 degrees spatial step is investigated. The latitudinal time series for summer and winter are separated. The summer (August) period has the climatic stable dependence of the surface temperature growth rate in the direction from the tropics to the subarctic area. The characteristic rate of temperature rise in tropical latitudes is 0.011 0C / year; in the subtropics is 0.021 0C / year; in subarctic waters above 40 0N this is 0.027 0C / year. The winter season (February) does not have this tendency. The quantitative estimates of the temperature trends influence on global circulation are presented. The SST growth enhances vertical stratification and decreases the vertical water exchange. The estimation of the relative vertical speed decrease is not more than 0.01% / decade. The quantitative assessment of the weakening of the geostrophic horizontal velocity in the Kuroshio extension due to the climatic smoothing of the SST south - north gradient is presented.

Recent intensified influence of the winter North Pacific sea surface temperature on the withdrawal date of Meiyu

2021 ◽  
pp. 1-53
Author(s):  
Hua Li ◽  
Shengping He ◽  
Ke Fan ◽  
Yong Liu ◽  
Xing Yuan
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Interannual Variability ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Sea Surface ◽  
The North ◽  
Time Period ◽  
The North Pacific ◽  
Sst Anomalies

AbstractThe Meiyu withdrawal date (MWD) is a crucial indicator of flood/drought conditions over East Asia. It is characterized by a strong interannual variability, but its underlying mechanism remains unknown. We investigated the possible effects of the winter sea surface temperature (SST) in the North Pacific Ocean on the MWD on interannual to interdecadal timescales. Both our observations and model results suggest that the winter SST anomalies associated with the MWD are mainly contributed by a combination of the first two leading modes of the winter SST in the North Pacific, which have a horseshoe shape (the NPSST). The statistical results indicate that the intimate linkage between the NPSST and the MWD has intensified since the early 1990s. During the time period 1990–2016, the NPSST-related SST anomalies persisted from winter to the following seasons and affected the SST over the tropical Pacific in July. Subsequently, the SST anomalies throughout the North Pacific strengthened the southward migration of the East Asian jet stream (EAJS) and the southward and westward replacement of the western North Pacific subtropical high (WPSH), leading to an increase in Meiyu rainfall from July 1 to 20. More convincingly, the anomalous EAJS and WPSH induced by the SST anomalies can be reproduced well by numerical simulations. By contrast, the influence of the NPSST on the EASJ and WPSH were not clear between 1961 and 1985. This study further illustrates that the enhanced interannual variability of the NPSST may be attributed to the more persistent SST anomalies during the time period 1990–2016.

scholarly journals Surface Movement, Hydrological Change and Equilibrium Flow on Lemon Creek Glacier, Alaska

1964 ◽  
Vol 5 (37) ◽  
pp. 61-75 ◽  
Author(s):  
Calvin J. Heusser ◽  
Melvin G. Marcus
Keyword(s):  
Field Research ◽  
Surface Flow ◽  
Equilibrium Flow ◽  
Flow Measurements ◽  
The North ◽  
International Geophysical Year ◽  
Ice Field ◽  
Glacier Flow ◽  
One Year ◽  
The One

AbstractLemon Creek Glacier served as the focus of attention of the Juneau Ice Field Research Project from 1953 through 1958. During the International Geophysical Year, it represented one of the glaciological stations in the North American network. This paper presents some of the results of these studies, its purposes being (1) to discuss the 1953–58 annual hydrological budgets, and (2) to test Nielsen’s equations for the equilibrium glacier using 1957 and 1958 movement and hydrological data.It is found that each budget year for the period studied shows a deficit, except 1954–55 which registered a pronounced surplus. The net deficit amounts to 10.32×106 m.3 of water. The 1956–57 budget was only slightly negative (0.82×106m.3) but that for 1957–58 was strongly negative (8.96×106 m.3). Surface flow measurements were made along five transverse profiles, two of which were plotted over one full year. It is believed that the one-year measurements provide a more accurate and realistic picture of glacier flow than is normally available from short summer surveys. Thu glacier appears to be close to equilibrium and to behave in the manner predicted by Nielsen’s theory of equilibrium flow.

scholarly journals Wind- versus Eddy-Forced Regional Sea Level Trends and Variability in the North Pacific Ocean

2015 ◽  
Vol 28 (4) ◽  
pp. 1561-1577 ◽  
Author(s):  
Bo Qiu ◽  
Shuiming Chen ◽  
Lixin Wu ◽  
Shinichiro Kida
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Momentum Flux ◽  
North Pacific Ocean ◽  
Kuroshio Extension ◽  
The Past ◽  
The North ◽  
The Pacific ◽  
Regional Sea Level ◽  
Sea Level Trend

Abstract Regional sea level trend and variability in the Pacific Ocean have often been considered to be induced by low-frequency surface wind changes. This study demonstrates that significant sea level trend and variability can also be generated by eddy momentum flux forcing due to time-varying instability of the background oceanic circulation. Compared to the broad gyre-scale wind-forced variability, the eddy-forced sea level changes tend to have subgyre scales and, in the North Pacific Ocean, they are largely confined to the Kuroshio Extension region (30°–40°N, 140°–175°E) and the Subtropical Countercurrent (STCC) region (18°–28°N, 130°–175°E). Using a two-layer primitive equation model driven by the ECMWF wind stress data and the eddy momentum fluxes specified by the AVISO sea surface height anomaly data, the relative importance of the wind- and eddy-forced regional sea level trends in the past two decades is quantified. It is found that the increasing (decreasing) trend south (north) of the Kuroshio Extension is due to strengthening of the regional eddy forcing over the past two decades. On the other hand, the decreasing (increasing) sea level trend south (north) of the STCC is caused by the decadal weakening of the regional eddy momentum flux forcing. These decadal eddy momentum flux changes are caused by the background Kuroshio Extension and STCC changes in connection with the Pacific decadal oscillation (PDO) wind pattern shifting from a positive to a negative phase over the past two decades.

Multidecadal Climate Variability in Observed and Modeled Surface Temperatures*

2008 ◽  
Vol 21 (5) ◽  
pp. 1104-1121 ◽  
Author(s):  
Sergey Kravtsov ◽  
Christopher Spannagle
Keyword(s):  
Climate Variability ◽  
Surface Temperature ◽  
Thermohaline Circulation ◽  
North Pacific Ocean ◽  
Coupled Model ◽  
Atlantic Multidecadal Oscillation ◽  
Temperature Evolution ◽  
Past Century ◽  
The North ◽  
Surface Temperatures

Abstract This study identifies interdecadal natural climate variability in global surface temperatures by subtracting, from the observed temperature evolution, multimodel ensemble mean based on the World Climate Research Programme's (WCRP) Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset. The resulting signal resembles the so-called Atlantic multidecadal oscillation (AMO) and is presumably associated with intrinsic dynamics of the oceanic thermohaline circulation (THC). While certain phases of the oscillation are dominated by the anomalies in the North Atlantic region, other phases are characterized by global teleconnections to the North Pacific Ocean, tropical Atlantic Ocean, as well as the Southern Ocean. In particular, natural variability of sea surface temperature in the Atlantic hurricanes’ main development region has a peak-to-peak amplitude comparable in magnitude to this region’s surface temperature increase over the past century, for all seasons. Evidence suggests that the AMO influence on secular trends in the global-mean surface temperature can arise via direct, regional contribution to the surface temperature evolution, as well as via an indirect route linked to variability of the oceanic uptake of CO2 associated with AMO-related THC changes.

scholarly journals Ethiopian Highlands Crop-Climate Prediction: 1979–2009

2013 ◽  
Vol 52 (5) ◽  
pp. 1116-1126 ◽  
Author(s):  
Mark R Jury
Keyword(s):  
Surface Temperature ◽  
Zonal Wind ◽  
Lead Time ◽  
Crop Yields ◽  
North Pacific Ocean ◽  
Principal Component ◽  
Time Correlation ◽  
Air Pressure ◽  
Ethiopian Highlands ◽  
The North

AbstractThis study compares different methods of predicting crop-related climate in the Ethiopian highlands for the period 1979–2009. A target index (ETH4) is developed as an average of four variables in the June–September season—rainfall, rainfall minus evaporation, estimated latent heat flux, and vegetation, following correlation with crop yields at Melkassa, Ethiopia (8.4°N, 39.3°E, 1550 m elevation). Predictors are drawn from gridded near-global fields of surface temperature, surface air pressure, and 200-hPa zonal wind in the preceding December–March season. Prediction algorithms are formulated by stepwise multivariate regression. The first set of predictors derive from objective principal component (PC) time scores with tropical loading patterns, and the second set is based on key areas determined from correlation with the target index. The second PC of upper zonal wind reveals a tropical–subtropical dipole that is correlated with ETH4 at two-season lead time (correlation coefficient r = −0.53). Point-to-field regression maps show high-latitude signals in surface temperature (positive in North America and negative in Eurasia) and air pressure (negative in the North Pacific Ocean and positive in the South Pacific). Upper zonal winds are most strongly related with ETH4 over the tropical Pacific and Africa at two-season lead time. The multivariate algorithm that is based on PC predictors has an adjusted r2 fit of 0.23, and the algorithm using key-area predictors achieves r2 = 0.37. In comparison, numerical model forecasts reach r2 = 0.33 for ECMWF simulations but are low for other models. The statistical results are specific to the ETH4 index, which is a climate proxy for crop yields in the Ethiopian highlands.

scholarly journals Improvement of Initialized Decadal Predictions over the North Pacific Ocean by Systematic Anomaly Pattern Correction

2014 ◽  
Vol 27 (13) ◽  
pp. 5148-5162 ◽  
Author(s):  
Hye-Mi Kim ◽  
Yoo-Geun Ham ◽  
Adam A. Scaife
Keyword(s):  
Pacific Ocean ◽  
Surface Temperature ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Systematic Errors ◽  
Prediction Skill ◽  
Coupled Models ◽  
The North ◽  
High Prediction ◽  
The North Pacific

The prediction skill and errors in surface temperature anomalies in initialized decadal hindcasts from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are assessed using six ocean–atmosphere coupled models initialized every year from 1961 to 2008. The initialized hindcasts show relatively high prediction skill over the regions where external forcing dominates, indicating that a large portion of the prediction skill is due to the long-term trend. After removing the linear trend, high prediction skill is shown near the centers of action of the dominant decadal climate oscillations, such as the Pacific decadal oscillation (PDO) and Atlantic multidecadal oscillation (AMO). Low prediction skill appears over the tropical and eastern North Pacific Ocean where the predicted anomaly patterns associated with the PDO are systematically different in model and observations. By statistically correcting those systematic errors using a stepwise pattern projection method (SPPM) based on the data in an independent training period, the prediction skill of sea surface temperature (SST) is greatly enhanced over the North Pacific Ocean. The SST prediction skill over the North Pacific Ocean after the SPPM error correction is as high as that over the North Atlantic Ocean. In addition, the prediction skill in a single model after correction exceeds the skill of the multimodel ensemble (MME) mean before correction, implying that the MME method is not as effective in addressing systematic errors as the SPPM correction.

scholarly journals The North Pacific–Driven Severe Midwest Winter of 2013/14

2015 ◽  
Vol 54 (10) ◽  
pp. 2141-2151 ◽  
Author(s):  
Alan Marinaro ◽  
Steve Hilberg ◽  
David Changnon ◽  
James R. Angel
Keyword(s):  
North Pacific ◽  
North Pacific Ocean ◽  
Winter Season ◽  
Circulation Pattern ◽  
Severity Index ◽  
Eastern United States ◽  
Climate Conditions ◽  
The North ◽  
Ice Coverage ◽  
The North Pacific

AbstractThe severe 2013/14 winter (December–March) in the Midwest was dominated by a persistent atmospheric circulation pattern anchored to a North Pacific Ocean that was much warmer than average. Strong teleconnection magnitudes of the eastern Pacific oscillation (−EPO), tropical Northern Hemisphere pattern (+TNH), and second-lowest Hudson Bay 500-hPa geopotential height field are indicators that led to severe winter weather across the eastern United States. Unlike in previous cold and snowy midwestern winters, Atlantic Ocean blocking played little to no role in the winter of 2013/14. The primary atmospheric feature of the 2013/14 winter was the 500-hPa high pressure anchored over the North Pacific in response to the extremely warm sea surface temperature anomalies observed of +3.7 standard deviations. Only one other severe midwestern winter (1983/84) since 1950 featured a similar Pacific blocking. The accumulated winter season severity index, which is a metric that combines daily snowfall, snow depth, and temperature data for the winter season, was used to compare the 2013/14 winter with past winters since 1950. Detroit, Michigan, and Duluth, Minnesota, experienced their worst winter of the 55-yr period. Seven climate divisions in northern Illinois, eastern Iowa, and parts of Wisconsin experienced record-cold mean temperatures. These climate conditions were associated with a number of impacts, including a disruption to the U.S. economy, the second-highest ice coverage of the Great Lakes since 1973, and a flight-cancellation rate that had not been seen in 25 years.

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