Global distribution and interannual variation in the winter halocline

2021 ◽  
Keyword(s):  
North Pacific ◽  
Interannual Variation ◽  
World Ocean ◽  
Correlation Coefficients ◽  
Gulf Of Alaska ◽  
Sea Surface Salinity ◽  
Ekman Pumping ◽  
Surface Salinity ◽  
The World ◽  
Definition Of

Abstract The distribution and interannual variation in the winter halocline in the upper layers of the world ocean were investigated via analyses of hydrographic data from the World Ocean Database 2013 using a simple definition of the halocline. A halocline was generally observed in the tropics, equatorward portions of subtropical regions, subarctic North Pacific and Southern Ocean. A strong halocline tended to occur in areas where the sea surface salinity (SSS) was low. The interannual variation in halocline strength was correlated with variation in SSS. The correlation coefficients were usually negative: the halocline was strong when the SSS was low. However, in the Gulf of Alaska in the northeastern North Pacific, the correlation coefficient was positive. There, halocline strength was influenced by interannual variation in Ekman pumping.

scholarly journals Temperature Inversions in the Subarctic North Pacific

2005 ◽  
Vol 35 (12) ◽  
pp. 2444-2456 ◽  
Author(s):  
Hiromichi Ueno ◽  
Ichiro Yasuda
Keyword(s):  
North Pacific ◽  
North Pacific Ocean ◽  
World Ocean ◽  
Gulf Of Alaska ◽  
Tidal Mixing ◽  
Large Temperature ◽  
Hydrographic Data ◽  
Subarctic North Pacific ◽  
The World ◽  
Temperature Inversions

Abstract Hydrographic data from the World Ocean Database 2001 and Argo profiling floats were analyzed to study temperature inversions in the subarctic North Pacific Ocean. The frequency distribution of temperature inversions [F(t-inv)] at a resolution of 1° (latitude) × 3° (longitude) was calculated. Temperature inversions seldom occurred around 50°N in the eastern subarctic North Pacific but were more common in the northern Gulf of Alaska and the southeastern subarctic North Pacific (42°–48°N, 140°–170°W). Large temperature inversions occurred throughout the year in the western and central subarctic North Pacific (north of 42°N and west of 180°) except near the Aleutian and Kuril Islands. Near those islands, F(t-inv) was characterized by pronounced seasonal variations forced by surface heating/cooling and strong tidal mixing.

scholarly journals Intercomparison of Global Sea Surface Salinity from Multiple Datasets over 2011–2018

2021 ◽  
Vol 13 (4) ◽  
pp. 811
Author(s):  
Hao Liu ◽  
Zexun Wei
Keyword(s):  
Time Scales ◽  
Correlation Coefficients ◽  
Dominant Mode ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Salinity ◽  
Ocean Data Assimilation ◽  
Multiple Datasets ◽  
Different Time Scales

The variability in sea surface salinity (SSS) on different time scales plays an important role in associated oceanic or climate processes. In this study, we compare the SSS on sub-annual, annual, and interannual time scales among ten datasets, including in situ-based and satellite-based SSS products over 2011–2018. Furthermore, the dominant mode on different time scales is compared using the empirical orthogonal function (EOF). Our results show that the largest spread of ten products occurs on the sub-annual time scale. High correlation coefficients (0.6~0.95) are found in the global mean annual and interannual SSSs between individual products and the ensemble mean. Furthermore, this study shows good agreement among the ten datasets in representing the dominant mode of SSS on the annual and interannual time scales. This analysis provides information on the consistency and discrepancy of datasets to guide future use, such as improvements to ocean data assimilation and the quality of satellite-based data.

scholarly journals Effects of Tropical Cyclones on Sea Surface Salinity in the Bay of Bengal Based on SMAP and Argo Data

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2975
Author(s):  
Huabing Xu ◽  
Rongzhen Yu ◽  
Danling Tang ◽  
Yupeng Liu ◽  
Sufen Wang ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Bay Of Bengal ◽  
Vertical Mixing ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Ekman Pumping ◽  
Surface Salinity ◽  
Argo Data ◽  
Before And After ◽  
The Impact

This paper uses the Argo sea surface salinity (SSSArgo) before and after the passage of 25 tropical cyclones (TCs) in the Bay of Bengal from 2015 to 2019 to evaluate the sea surface salinity (SSS) of the Soil Moisture Active Passive (SMAP) remote sensing satellite (SSSSMAP). First, SSSArgo data were used to evaluate the accuracy of the 8-day SMAP SSS data, and the correlations and biases between SSSSMAP and SSSArgo were calculated. The results show good correlations between SSSSMAP and SSSArgo before and after TCs (before: SSSSMAP = 1.09SSSArgo−3.08 (R2 = 0.69); after: SSSSMAP = 1.11SSSArgo−3.61 (R2 = 0.65)). A stronger negative bias (−0.23) and larger root-mean-square error (RMSE, 0.95) between the SSSSMAP and SSSArgo were observed before the passage of 25 TCs, which were compared to the bias (−0.13) and RMSE (0.75) after the passage of 25 TCs. Then, two specific TCs were selected from 25 TCs to analyze the impact of TCs on the SSS. The results show the significant SSS increase up to the maximum 5.92 psu after TC Kyant (2016), which was mainly owing to vertical mixing and strong Ekman pumping caused by TC and high-salinity waters in the deep layer that were transported to the sea surface. The SSSSMAP agreed well with SSSArgo in both coastal and offshore waters before and after TC Roanu (2016) and TC Kyant (2016) in the Bay of Bengal.

scholarly journals Estimating temporal and spatial variation of ocean surface <i>p</i>CO<sub>2</sub> in the North Pacific using a self-organizing map neural network technique

2013 ◽  
Vol 10 (9) ◽  
pp. 6093-6106 ◽  
Author(s):  
S. Nakaoka ◽  
M. Telszewski ◽  
Y. Nojiri ◽  
S. Yasunaka ◽  
C. Miyazaki ◽  
...  
Keyword(s):  
Neural Network ◽  
North Pacific ◽  
Mixed Layer Depth ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Self Organizing Map ◽  
Surface Salinity ◽  
The North ◽  
The North Pacific ◽  
Self Organizing

Abstract. This study uses a neural network technique to produce maps of the partial pressure of oceanic carbon dioxide (pCO2sea) in the North Pacific on a 0.25° latitude × 0.25° longitude grid from 2002 to 2008. The pCO2sea distribution was computed using a self-organizing map (SOM) originally utilized to map the pCO2sea in the North Atlantic. Four proxy parameters – sea surface temperature (SST), mixed layer depth, chlorophyll a concentration, and sea surface salinity (SSS) – are used during the training phase to enable the network to resolve the nonlinear relationships between the pCO2sea distribution and biogeochemistry of the basin. The observed pCO2sea data were obtained from an extensive dataset generated by the volunteer observation ship program operated by the National Institute for Environmental Studies (NIES). The reconstructed pCO2sea values agreed well with the pCO2sea measurements, with the root-mean-square error ranging from 17.6 μatm (for the NIES dataset used in the SOM) to 20.2 μatm (for independent dataset). We confirmed that the pCO2sea estimates could be improved by including SSS as one of the training parameters and by taking into account secular increases of pCO2sea that have tracked increases in atmospheric CO2. Estimated pCO2sea values accurately reproduced pCO2sea data at several time series locations in the North Pacific. The distributions of pCO2sea revealed by 7 yr averaged monthly pCO2sea maps were similar to Lamont-Doherty Earth Observatory pCO2sea climatology, allowing, however, for a more detailed analysis of biogeochemical conditions. The distributions of pCO2sea anomalies over the North Pacific during the winter clearly showed regional contrasts between El Niño and La Niña years related to changes of SST and vertical mixing.

Optimized global map projections for specific applications: the triptychial projection and the Spilhaus projection

2020 ◽  
Author(s):  
Björn Grieger
Keyword(s):  
World Ocean ◽  
Elliptic Functions ◽  
Complete Information ◽  
Full Detail ◽  
Map Projections ◽  
Minimal Distortion ◽  
The World ◽  
One Step ◽  
Definition Of ◽  
First Time

&lt;p&gt;There is no perfect global map projection. A projection may be area preserving or conformal (shape preserving on small scales) in some regions, but it will inevitably exhibit considerable distortions in others. An oblique version of a projection (where the globe is rotated before projecting) can be optimized to avoid major distortions in specific regions of interest.&lt;br&gt;We present two global map projections of the Earth which either display all continents (including Antarctica) or the complete world ocean with minimal distortion and without any intersection. These are the triptychial projection and the Spilhaus projection, respectively.&lt;br&gt;The triptychial projection is original work and has been published by Grieger (2019). While that paper comprises complete information on the definition of the projection, the details of its application need to be collected from literature referenced therein. The triptychial projection is an oblique and rearranged version of the Peirce quincuncial projection of the world (Peirce, 1879).&lt;br&gt;Instances of the Spilhaus projection went viral on the internet in fall 2018. The projection is mostly attributed to a publication from 1942, but in fact it seems to appear for the first time in Spilhaus (1979). The projection is shown in that paper (and in a few later ones), but no information on its definition is provided. Developers of ArcGIS did some reverse engineering and could identify the Spilhaus projection as an oblique version of the Adams projection of the world in a square II (Adams, 1929).&lt;br&gt;The triptychial and the Spilhaus projection both imply several steps in their application. While the two projections look very different, they have one step in common: the conformal mapping of a hemisphere onto a square, which requires tabulated Jacobi elliptic functions. We review both projections, describe them in full detail, and provide all formulas and data needed to apply them. The algorithms employed may also be interesting for planetary applications.&lt;/p&gt;

scholarly journals Stationary Eddies and the Zonal Asymmetry of Net Precipitation and Ocean Freshwater Forcing

2015 ◽  
Vol 28 (13) ◽  
pp. 5115-5133 ◽  
Author(s):  
Robert C. Wills ◽  
Tapio Schneider
Keyword(s):  
Spatial Variability ◽  
Large Scale ◽  
Vertical Motion ◽  
Sea Surface Salinity ◽  
Specific Humidity ◽  
Ekman Pumping ◽  
Surface Salinity ◽  
The North ◽  
Freshwater Forcing ◽  
The Pacific

Abstract Transport of water vapor in the atmosphere generates substantial spatial variability of net precipitation (precipitation minus evaporation). Over half of the total spatial variability in annual-mean net precipitation is accounted for by deviations from the zonal mean. Over land, these regional differences determine differences in surface water availability. Over oceans, they account, for example, for the Pacific–Atlantic difference in sea surface salinity, with implications for the deep overturning circulation. This study analyzes the atmospheric water budget in reanalyses from ERA-Interim and MERRA, to investigate which physical balances lead to zonal variation in net precipitation. It is found that the leading-order contribution is zonal variation in stationary-eddy vertical motion. Transient eddies modify the pattern of zonally anomalous net precipitation by moving moisture from the subtropical and tropical oceans onto land and poleward across the Northern Hemisphere storm tracks. Zonal variation in specific humidity and stationary-eddy horizontal advection play a secondary role. The dynamics leading to net precipitation via vertical motion in stationary eddies can be understood from a lower-tropospheric vorticity budget. The large-scale variations of vertical motion are primarily described by Sverdrup balance and Ekman pumping, with some modification by transient eddies. These results suggest that it is important to understand changes in stationary eddies and their influence on the zonal variation of transient eddy fluxes, in order to understand regional changes in net precipitation. They highlight the relative importance of different atmospheric mechanisms for the freshwater forcing of the North Pacific and North Atlantic.

scholarly journals Global-scale patterns of observed sea surface salinity intensified since the 1870s

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
W. John Gould ◽  
Stuart A. Cunningham
Keyword(s):  
Hydrological Cycle ◽  
Global Scale ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Salinity Change ◽  
Surface Salinity ◽  
Salinity Changes ◽  
Change Pattern ◽  
The World ◽  
Global Mean

AbstractSea surface salinity patterns have intensified between the mid-20th century and present day, with saline areas becoming saltier and fresher areas fresher. This change has been linked to a human-induced strengthening of the global hydrological cycle as global mean surface temperatures rose. Here we analyse salinity observations from the round-the-world voyages of HMS Challenger and SMS Gazelle in the 1870s, early in the industrial era, to reconstruct surface salinity changes since that decade. We find that the amplification of the salinity change pattern between the 1870s and the 1950s was at a rate that was 54 ± 10% lower than the post-1950s rate. The acceleration in salinity pattern amplification over almost 150 years implies that the hydrological cycle would have similarly accelerated over this period.

scholarly journals Disribution of elements in ferrum-manganese nodules in seas and lakes

2019 ◽  
pp. 404-417
Author(s):  
G. N. Baturin
Keyword(s):  
World Ocean ◽  
Correlation Coefficients ◽  
Element Composition ◽  
Manganese Nodules ◽  
High Concentration ◽  
The World

The element composition of manganese nodules from the inner lakes and arctic seases has beeb studied for comparison with ferrum-manganese nodules from the World ocean which helped to find their similar and different features as well as the trends to accumulate more elements which is related to their ferrum-manganese environment. The correlation coefficients have been calculated for all samples. The high concentration of ferrum-manganese and iron in arctic nodules.

scholarly journals Estimating temporal and spatial variation of ocean surface <i>p</i>CO<sub>2</sub> in the North Pacific using a Self Organizing Map neural network technique

2013 ◽  
Vol 10 (3) ◽  
pp. 4575-4610 ◽  
Author(s):  
S. Nakaoka ◽  
M. Telszewski ◽  
Y. Nojiri ◽  
S. Yasunaka ◽  
C. Miyazaki ◽  
...  
Keyword(s):  
Neural Network ◽  
North Pacific ◽  
Mixed Layer Depth ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Self Organizing Map ◽  
Surface Salinity ◽  
The North ◽  
The North Pacific ◽  
Self Organizing

Abstract. This study produced maps of the partial pressure of oceanic carbon dioxide (pCO2sea) in the North Pacific on a 0.25° latitude × 0.25° longitude grid from 2002 to 2008. The pCO2sea values were estimated by using a self-organizing map neural network technique to explain the non-linear relationships between observed pCO2sea data and four oceanic parameters: sea surface temperature (SST), mixed layer depth, chlorophyll a concentration, and sea surface salinity (SSS). The observed pCO2sea data was obtained from an extensive dataset generated by the volunteer observation ship program operated by the National Institute for Environmental Studies. The reconstructed pCO2sea values agreed rather well with the pCO2sea measurements, the root mean square error being 17.6 μatm. The pCO2sea estimates were improved by including SSS as one of the training parameters and by taking into account secular increases of pCO2sea that have tracked increases in atmospheric CO2. Estimated pCO2sea values accurately reproduced pCO2sea data at several stations in the North Pacific. The distributions of pCO2sea revealed by seven-year averaged monthly pCO2sea maps were similar to Lamont-Doherty Earth Observatory pCO2sea climatology and more precisely reflected oceanic conditions. The distributions of pCO2sea anomalies over the North Pacific during the winter clearly showed regional contrasts between El Niño and La Niña years related to changes of SST and vertical mixing.

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