Associating Michigan climate with low-level airflow trajectories and atmospheric teleconnections

Abstract

The climate of Michigan is influenced by airflow circulation associated with atmospheric teleconnections. Previous studies have investigated mid-level airflow and atmospheric teleconnections, while low-level airflow has had less attention. Analyses of low-level airflow trajectories and atmospheric teleconnection associations are presented for a location in Lower Michigan. Airflow trajectories, which provide an important approach to monitoring changes in atmospheric circulation, are used to represent the low-level circulation during 1950−2011. A 5-day back-trajectory climatology for the 925 hPa pressure level was developed using the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) reanalysis data archive. Low-level and mid-level circulation associated with the North Atlantic Oscillation (NAO), the Pacific/North American pattern (PNA), and El Niño/La Niña (NINO3.4) highlighted advection of heat and moisture during particular times of the year and the presence of single or simultaneous strong atmospheric teleconnections. The results indicate that airflow associated with teleconnections often differs seasonally. Additionally, trajectory patterns vary, based on whether a single strong teleconnection is present or if 2 strong teleconnections are coexisting. Using low-level airflow anomalies assists in bridging the gap between local-scale climate anomalies, such as temperature and precipitation, and atmospheric teleconnections. While a climatological study is presented here, the knowledge obtained could be applied in modeling and contribute to improved medium-and long-range forecasts.