Tipping elements of the Indian monsoon : Prediction of onset and withdrawal

Funded by LINC project. Grant Number: 289447 EC's Marie Curie ITN program. Grant Number: FP7-PEOPLE-2011-ITN RFBR. Grant Number: 16-07-01186 Government of Russian Federation. Grant Number: 14.Z50.31.0033Peer reviewedPublisher PD

Recent climate changes of thermohaline structure in the North-West Pacific

Variability of temperature and salinity in the 0-1000-m layer of the North-West Pacific is analyzed on the data of shipboard oceanographic observations obtained in 1950-2014. Significant decadal changes of these parameters are revealed at the depth of 300-600 m that exceeds the depth of seasonal fluctuations, with the highest rate in the Subarctic frontal zone. The heat content was the highest in the 1960-1974, then decreased in the 1975-1999, increased again in the 2000-2014, and the next phase of thermal «discharge» may begin supposedly in 5-6 years. Mechanisms of such climate changes are discussed. Similar changes are observed in different regions of the World Ocean that means that it is a global-scale phenomenon. These climate changes of water temperature in the subsurface layer of the ocean and air temperature over the continent have opposite directions that denotes the auto-oscillation in the open non-linear system «ocean-atmosphere-continent» as their main mechanism. The previous period of the water thermal discharge was conditioned by active winter center of low atmospheric pressure - Aleutian Low. It was accompanied by strengthening of the East-Kamchatka Current and Oyashio Current and high abundance of japanese sardine. The modern period of warming from the beginning of the 21st century is distinguished by negative values of PDO index, observed since 1998. However, PDO is positive again since January 2014, though stability of this change is not clear yet. On the other hand, winter SST in the spawning grounds of japanese sardine, both in the Japan Sea and North-West Pacific, gradually decreased after the maximum in the 1998-2000 and reached negative anomalies in the areas at Japan in 2011-2015 that was favorable for its reproduction. The sardine biomass was gradually increased, too, in particularly in the 2010-2012, and its migration to the Russian EEZ became more active, up to 0.7 million tons in the South-Kuril area in 2015

A view of the Canary Basin thermocline circulation in winter

During January and February 1989 the recirculation of the subtropical gyre in the eastern North Atlantic was surveyed with a three-ship experiment. The analysis of hydrographic measurements and velocity data from a shipboard acoustic Doppler current profiler reveals the synoptic-scale circulation patterns and water mass distributions in the Canary Basin. The geostrophic transport stream function estimated with a horizontally varying reference level of no motion highlights the major currents in three layers representing the vertical structure of the horizontal circulation. The classical circulation scheme is shown by the stream function in the upper 200 m: the Azores, Canary, and North Equatorial currents. Unlike the deep-penetrating Azores Current, the Canary Current and the North Equatorial Current are restricted to the upper 200 m. Both carry North Atlantic Central Water along the water mass boundary with South Atlantic Central Water. South Atlantic Central Water flows through the passage between the Cape Verde archipelago and Africa via narrow currents into the area north of 14.5°N. At the southern edge of the subtropical gyre we identify an eastward flow of Antarctic Intermediate Water between 700 and 1200 m

Multidecadal Phase Changes in the Thermodynamic State of the System: Ocean–Atmosphere–Continent

The present-day climate (the recent 100–150 years) obviously constitutes the structure of a global intra-system rhythmic process with an individual rhythm of about 60 years. In turn, each of the rhythms is presented by the two climate phases of about 25–35 years characterized by qualitative differences: one phase is relatively continental, while the other is humid. Globality and quasi-synchronism of environmental changes are accompanied by planetary structures: the Global Atmospheric Oscillation (GAO) in the atmosphere and the Multidecadal Oscillation of the Heat content in the Ocean (MOHO) discovered relatively recently. Unexpected and rapid qualitative phase changes in the climate, which first focused attention in the mid-1970s of the last century, were titled “climate shifts”. The revealed features of the present-day climate are of exceptional scientific and practical interest and deserve the development of methods for predicting the timing of the forthcoming climate shift. Arising unexpectedly and accompanied by rapid significant changes, these shifts identified the problem of understanding the nature and establishing the processes and mechanisms causing them. First of all, of interest are phase changes in the thermodynamic state of the climate system components: the ocean, atmosphere, and continents. As a result of the World Ocean (WO) thermohydrodynamics numerical modelling, it is shown that MOHO is localized in the layer of the main thermocline, where the most important elements of the WO circulation are located. The performed study based on observational data allows us to conclude that, during the phase of the WO thermal discharge (1975–1999), the two key systems of currents, the Kuroshio and the Gulf Stream, were under similar thermodynamic conditions

Interdecadal Oscillation of the Ocean Heat Content as a Contribution to Understanding of Physical Aspects of the Present-Day Climate

A Specific feature of the present-day climate dynamics consists in its multidecadal oscillations with a period of about 20–60 years, and intradecadal disturbances with time scales of 2–8 years. The period of 1940–1999 was distinctive due to the two–phase structure in which the initial phase (1940–1974) was substantially dry, and the final one (1975–1999) was relatively humid. The transition of the climate from the dry to the humid phase in the mid-1970s was recognized as a climatic shift. The certain globality and quasisynchronism of multidecadal climate changes occur involving planetary thermodynamic structures in the two most important components of the climate system, namely, the ocean and the atmosphere. The search for the origin of the observed present-day climate variability revealed the World Ocean (WO) active upper layer (AUL) heat content to demonstrate sequential multidecadal phases of heat accumulation and discharge consistent with multidecadal phases of climate disturbances. Thus, the WO AUL heat accumulation phase corresponds to a dry climate, and its thermal discharge corresponds to a relatively humid one. The mechanism of the observed multidecadal phase variability in the present-day climate consists of the planetary intrasystemic redistribution of heat between WO and continental air masses, where the general circulation of the atmosphere plays the role of an intermediary

Interdecadal Oscillation of the Ocean Heat Content as a Contribution to Understanding of Physical Aspects of the Present-Day Climate

A Specific feature of the present-day climate dynamics consists in its multidecadal oscillations with a period of about 20–60 years, and intradecadal disturbances with time scales of 2–8 years. The period of 1940–1999 was distinctive due to the two–phase structure in which the initial phase (1940–1974) was substantially dry, and the final one (1975–1999) was relatively humid. The transition of the climate from the dry to the humid phase in the mid-1970s was recognized as a climatic shift. The certain globality and quasisynchronism of multidecadal climate changes occur involving planetary thermodynamic structures in the two most important components of the climate system, namely, the ocean and the atmosphere. The search for the origin of the observed present-day climate variability revealed the World Ocean (WO) active upper layer (AUL) heat content to demonstrate sequential multidecadal phases of heat accumulation and discharge consistent with multidecadal phases of climate disturbances. Thus, the WO AUL heat accumulation phase corresponds to a dry climate, and its thermal discharge corresponds to a relatively humid one. The mechanism of the observed multidecadal phase variability in the present-day climate consists of the planetary intrasystemic redistribution of heat between WO and continental air masses, where the general circulation of the atmosphere plays the role of an intermediary