A regional (land – ocean) comparison of the seasonal to decadal variability of the Northern Hemisphere jet stream 1871-2011

<p>Seasonal to decadal variations in Northern Hemisphere jet stream latitude and speed over land (Eurasia, North America) and oceanic (North Atlantic, North Pacific) regions are presented for the period 1871 &#8211; 2011 from the Twentieth Century Reanalysis dataset</p><p>Significant regional differences are seen on seasonal to decadal timescales. Seasonally, the&#160; jet latitude range is lower over the oceans compared to land, reduced from 20&#176; over Eurasia to 10&#176; over the North Atlantic where the ocean meridional heat transport is greatest. The mean jet latitude range is at a minimum in winter (DJF), particularly along the western boundary of the North Pacific and North Atlantic, where the land-sea contrast and SST gradients are strongest.</p><p>The 141-year trends in jet latitude and speed show differences on a regional basis. The largest increasing trends in jet latitude and jet speed are observed in the North Atlantic, with increases in winter of 3&#176; and 4.5ms-1, respectively. There are no trends in jet latitude or speed over the North Pacific.</p><p>Long term trends are overlaid by multi decadal variability. In the North Pacific, 20-year variability in jet latitude and jet speed are seen, associated with the Pacific Decadal Oscillation which explains 50% of the winter variance in jet latitude since 1940.</p><p>In addition, current work on a lead/lag analysis of western boundary currents/ocean variability in the North Atlantic and North Pacific and links to the northern hemisphere jet stream will be presented.</p><p>Hallam et al., A regional (land-ocean) comparison of the seasonal to decadal variability of the northern hemisphere jet stream. Climate Dynamics (2022 in revision).https://doi.org/10.21203/rs.3.rs-607067/v1</p><p>&#160;</p>