Abstract. Strong internal waves (IW) in the form of soliton groups were observed off the Oregon coast with in situ and remote sensors, including shore-based X band and K a band Doppler radars and an airborne microwave radiometer operating at 37 GHz. Here we analyze the relationships between oceanic isotherm vertical displacements, internal currents, and radar backscatter cross sections, along with Doppler velocity signals at horizontal (HH) and vertical (VV) polarizations, and 37-GHz brightness temperatures measured at intermediate incidence angles from an airship. Analysis of these observations shows that (1) the horizontal spatial structure of the IW field depends on whether it is forced by a strong (spring) tide or weak (neap) tide; (2) while both HH and VV are strongly modulated by IWs, the modulation depth of HH always exceeds that of VV, and they both increase with the IW amplitude; (3) 37-GHz brightness temperature modulations were in phase with radar signal modulations; and (4) the phase of radar signal modulation with respect to the IW is such that the minimum radar signal intensity and lowest microwave brightness temperature lie close to the maximum of the IW thermocline depression or, equivalently, the horizontal current excursion near the surface. This last observation conflicts with the expectation that the highest backscattered signal would be found near the region of greatest surface strain rate (the surface current gradient). Existing theoretical models are briefly reviewed for interactions between the IW field and the intensity of short gravity-capillary waves that might be responsible for this behavior. Introduction

Horizontal transport is a key factor in air pollution meteorology. In several recent air quality field campaigns, networks of wind profiling Doppler radars have been deployed to help characterize this important phenomenon. This paper describes a Lagrangian particle trajectory tool developed to take advantage of the hourly wind observations provided by these special profiler networks. The tool uses only the observed wind profiles to calculate trajectory positions and does not involve any model physics or parameterizations. An interpolation scheme is used to determine the wind speed and direction at any given location and altitude along the trajectory. Only the horizontal winds measured by the profilers are included because the type of profiling radars used in this study are unable to resolve synoptic‐scale vertical motions. The trajectory tool is applied to a case study from the International Consortium for Research on Transport and Transformation air quality experiment conducted during the summer of 2004 (ICARTT‐04). During this international field study, air chemistry observations were collected at Chebogue Point, a coastal station in southwestern Nova Scotia, and factor analysis was used to identify time periods when air pollution from the United States arrived at the site. The profiler trajectories are compared to trajectories produced from numerical model initialization fields. The profiler‐based trajectories more accurately reflect changes in the synoptic weather pattern that occurred between operational upper air soundings, thereby providing a more accurate depiction of the horizontal transport responsible for air pollution arriving in Nova Scotia.

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