Northern Hemisphere Jet Stream Position Indices as Diagnostic Tools for Climate and Ecosystem Dynamics

Abstract

The latitudinal position of the Northern Hemisphere jet stream (NHJ) modulates the occurrence and frequency of extreme weather events. Precipitation anomalies in particular are associated with NHJ variability; the resulting floods and droughts can have considerable societal and economic impacts. This study develops a new climatology of the 300-hPa NHJ using a bottom-up approach based on seasonally explicit latitudinal NHJ positions. Four seasons with coherent NHJ patterns were identified (January–February, April–May, July–August, and October–November), along with 32 longitudinal sectors where the seasonal NHJ shows strong spatial coherence. These 32 longitudinal sectors were then used as NHJ position indices to examine the influence of seasonal NHJ position on the geographical distribution of NH precipitation and temperature variability and their link to atmospheric circulation pattern. The analyses show that the NHJ indices are related to broad-scale patterns in temperature and precipitation variability, in terrestrial vegetation productivity and spring phenology, and can be used as diagnostic/prognostic tools to link ecosystem and socioeconomic dynamics to upper-level atmospheric patterns.

Drought, Heat, and the Carbon Cycle: a Review

“…The North Atlantic Oscillation is a meridional dipole in surface pressure that controls the position of the jet stream and winter circulation patterns regionally over Eastern North America and Eurasia [132] with implications for regionalscale carbon cycling: the European net carbon balance is jointly affected by the NAO and a southerly displaced pattern, the East Atlantic oscillation, i.e., for instance with both in their negative phases wet and cool summers tend to increase photosynthesis [133]. These conditions also tend to increase winter precipitation in Southern Europe [133] with positive effects on the C-cycle in these water-limited ecosystems.…”

North Atlantic Multidecadal Variability Enhancing Decadal Extratropical Extremes in Boreal Late Summer in the Early Twenty-First Century

“…Similar to the NA jet anomaly, the latitudinal position anomaly of the North Pacific jet (Shaman et al 2009;Belmecheri et al 2017) is also changed. However, the linkage of the North Pacific jet anomaly with extratropical extremes and the relationships between the NA jet and the North Pacific jet receive less attention.…”

“…The westerly jets Denotes content that is immediately available upon publication as open access. include the polar jet and subtropical jet, and the subtropical jets include the midlatitude North Atlantic (NA) jet (Trouet et al 2018), the North Pacific jet (Strong and Davis 2008;Belmecheri et al 2017), and the Afro-Asian jet (Branstator 2002); however, all of them show inconsistent variability at interannual to decadal time scales. Therefore, considering their different impacts, the jet effects on summer extremes should be discussed separately.…”

Spatial Variability in Growth‐Climate Relationships of Amur Cork Tree (Phellodendron amurense) and Their Connections With PDO in Northeast China

“…In our study, the spatial patterns of growth season length (the starting [spring onset] and ending [autumn termination] time of tree growth) and the effective accumulated temperature along latitudinal gradients influenced tree growth (Figure S4). Previous studies in North America and Eurasia have confirmed that the PDO can modulate the spatiotemporal variation of spring onset by affecting atmospheric circulation patterns and temperature variability (Ault et al, ; Belmecheri et al, ; Mccabe et al, ). The positive anomalies of PDO indicated high pressure over the northern part of our study region and low pressure in the south that favored warm air advection in the northwest and resulted in earlier leaf onset, later leaf loss, a longer growing season, and higher effective cumulative temperature associated with PDO (Figure S5).…”