Registration Number
0313U005012,
0112U008263
, R & D reports
Title
Research of seasonal and interannual variability of hydrometeorological characteristics in surface layer of Southern ocean and their connection with global processes in ocean-atmosphere system.
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Отримання характеристик сезонної та міжрічної мінливості водних мас та гідрологічних фронтів Південного океану на основі найбільш повних архівних баз контактних і супутникових даних та довгострокових даних ре-аналізу. Вивчення низькочастотної мінливості основних параметрів взаємодії океану і атмосфери в Антарктичному регіоні під впливом глобальних кліматичних процесів.
Head
Polonsky Alexander Borisovich,
Registration Date
18-01-2013
Organization
Marine Hydrophysical Institute NAS of Ukraine
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On the basis of modern climatic dataset, archived bases of the contact hydrological data, satellite measurements data and long-term re-analysis data the seasonal and interannual variability of temperature fronts characteristics, the water masses areas and large-scale currents in Western Antarctic region is investigated. Display of the Antarctic Dipole Mode in the SST fronts characteristics and water masses areas interannual variations is analyzed. Features of structure and a seasonal cycle of temperature fronts characteristics in the South Indian Ocean are revealed. The variability of thermal balance components on the Earth surface and the main meteoparameters in Southern hemisphere in connection with change of Pacific decade oscillation phases is investigated. Low-frequency variability of turbulent heat flux on the basis of the re-analysis NCEP/NCAR monthly data is investigated. It is shown that regional hydrometeorological and orographical features to the west and the east from Antarctic Peninsula influence interannual variability of fronts and water masses. Shown that the most accurately Antarctic dipole is expressed in the variability of Antarctic Polar front characteristics and the waters area located between Front of the Southern branch of Antarctic Circumpolar current and Antarctic Polar front. Research of structure and climatic seasonal variability of Subantarctic (SAF) and Antarctic polar (APF) fronts in South Indian Ocean on the basis of monthly average SST satellite measurements from archive AVHRR Ocean Pathfіnder Data JPL NOAA/NASA for 1985-2002 have shown that features of front's spatial structure are formed under influence of bottom configuration inhomogeneities. The intensive fronts meandering and appearance of the secondary branches in their structure are revealed. It is shown that intensity and a seasonal cycle of characteristics of fronts are influenced also by the bottom relief. SAF it is most intensive and characterised by steady intraannual position over Agulhas and Crozet hollows to the north of Kerguelen ridge. In the same areas the greatest seasonal changes of its intensity are marked. For APF the greatest intensity and its maximum seasonal variations are observed over the African-Antarctic ridge, to the east from the Kerguelen ridge and over east part of the Australian-Antarctic raise. Seasonal displacements of front small also increase only to the north of the Kerguelen ridge and over the southwest part of the Australian-Antarctic raise. On the basis of hydrological World Ocean Atlas-2009 data and the sea level anomalies (SLA) data from 1992 to 2010 the seasonal variability of surface geostrophic currents in the Western Antarctic between 40W and 100W is analyzed. Comparison of the results received on different methods of calculation, combining monthly-average, annual-average hydrological data and monthly average SLA values is made. It is shown that the different methods in most cases show quality identical character of seasonal signal. The concept about seasonal signal propagation to east direction is confirmed. The main maximum of velocity of Antarctic circumpolar current (АCC) branches in the Western Atlantic sector of Southern ocean and in Drake Passage is observed mainly in second half of summer and in the early autumn of Southern hemisphere, in Pacific Ocean to the west 80W - in the end of winter and the beginning of spring. The variability of thermal balance components on the Earth surface and the main meteoparameters in Southern hemisphere in connection with change of Pacific decade oscillation phases is investigated. Changes of thermal balance components on the Earth surface, air temperature, atmospheric pressure and wind speed in Southern hemisphere which phases of the Pacific Decade Oscillation (PDO) on positive (1977-2004) to change negative (1948-1977) are considered. The monthly average values of balance of short-wave and long-wave radiation on spreading surface and sensible and latent heat flux from re-analysis NCEP/NCAR were used. Using this data the values of radiation balance and the full thermal balance on the Earth surface and a difference between their average values in warm (1977-2004) and cold (1948-1976) PDO phases have been calculated. The revealed basic distinctions of fields of components of full thermal balance on the ocean surface, and also ground air temperature, atmospheric pressure and wind speed averaged for the cold and warm PDO phases seasons. The most essential distinctions between average values of thermal balance components on the Earth surface in different PDO phases are observed in energy active areas of Southern ocean. The basic contribution to variability of thermal balance variability leads the sensible and latent heat flux, the appreciable payment of radiation balance variability is observed only in separate areas. Essential distinctions of air temperature over Antarctica in cold and warm PDO phase have inverse signs in the winter and summer seasons of Southern hemisphere. In warm PDO phase steady decreasing of atmospheric pressure average values around Antarctica and is observed both in the winter and summer. Wind speed in positive PDO phase in Antarctica region it above throughout all year. On the basis of NCEP re-analysis monthly data has been shown, that low-frequency variability of latent (LE) plus sensible (H) heat flux is ~ 13% of total variability. Maximal standard deviation of (H+LE) and (H) on low frequencies (T > 8 years) were found on the borders of the ice edge for period from March to August. Their values are in the range (25-100 W/m2) for STD (H+LE) and (25-80 W/m2) for STD (H). Variability is connected with seasonal shift of sea ice edge placement. Areas of low-frequency variability maximums of (H+LE) and (H) coincide. The reason of this is that in this areas Bowen ratio ?1, so sensible heat flux is a main component of (H+LE), which determine its low-frequency variability. New knowledge about the climate changes mechanisms on regional and global scales, obtained in result of the conducted researches in South Ocean, can find further application for the decision of ecological problems, estimation of quality of the coastal ecosystems state and rational development of coastal resources of the Antarctic region.
Product Description
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2020-04-02
