Principal Climate Indices for the North Pacific: Nature and History (A Review)

Abstract

Climatic indices reflecting the environmental conditions and patterns of their variability in the entire northern Pacific and in its local regions are overviewed. Their physical nature and mechanisms of the processes, their geography and methods of calculation are presented, with citing of the first descriptions. Among a variety of global and regional climatic indices concern ing the North Pacific, the following ones are described: the indices of Arctic Oscillation (AO), El Niño — Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Aleutian Low Pressure Index (ALPI), Siberian High Index (SHI), North Pacific Index (NPI), Pacific/North American (PNA) Index, and West Pacific Index (WP). AO is a large-scale index of atmospheric circulation reflecting the processes both in the troposphere and stratosphere, where «pumping» of air masses between the high and moderate latitudes occurs continuously. ENSO is also a large-scale index that reflects large-scale interactions in the fields of temperature, atmospheric pressure, wind, and cloudiness over the whole Pacific. Other indices are rather regional, since their influence does not extend far beyond the limits of the domains of their definition. Nevertheless, their role in environmental fluctuations in certain areas could be significant and their influence could be traced throughout the Northern Hemisphere.

Climatic factors affecting Kamchatka glacier recession

“…In the first decade of the 2000s, negative values of the PNA index prevailed. The cold phase of the PNA index is characterized by the predominance of high pressure in the North Pacific Ocean and the weakening of the Aleutian Low (Khen et al, 2019a). The Western Pacific Index WP characterizes the western part of the Pacific Ocean and has the greatest impact on the climate of the Russian Far East and, in particular, the Kamchatka Peninsula (Khen et al, 2019a).…”

“…The cold phase of the PNA index is characterized by the predominance of high pressure in the North Pacific Ocean and the weakening of the Aleutian Low (Khen et al, 2019a). The Western Pacific Index WP characterizes the western part of the Pacific Ocean and has the greatest impact on the climate of the Russian Far East and, in particular, the Kamchatka Peninsula (Khen et al, 2019a). The positive phase of the WP index is accompanied by an atmospheric pressure increase over Shelikhov Gulf and weakening of the Aleutian Low, the trajectory of cyclones in the Far East region shifts northward, and air temperature and precipitation increase in Kamchatka and Chukotka (Khen et al, 2019a; Kiktev et al, 2015).…”

“…The Western Pacific Index WP characterizes the western part of the Pacific Ocean and has the greatest impact on the climate of the Russian Far East and, in particular, the Kamchatka Peninsula (Khen et al, 2019a). The positive phase of the WP index is accompanied by an atmospheric pressure increase over Shelikhov Gulf and weakening of the Aleutian Low, the trajectory of cyclones in the Far East region shifts northward, and air temperature and precipitation increase in Kamchatka and Chukotka (Khen et al, 2019a; Kiktev et al, 2015). In the negative phase, the trajectories of cyclones, on the contrary, shift to the south and there is a shortage of precipitation.…”

Variability and Interrelation of the Basic Climate Indices for the North Pacific: Trends, Climate Shifts, Spectra, Correlations

“…The study is continuing, which first results were published in 2019 [Khen et al, 2019]. The main patterns of long-term variability are considered for selected climate indices in the North Pacific and links between them are identified on the common methodological basis.…”