Alexander A. Jacques

Central and Eastern U.S. Surface Pressure Variations Derived from the USArray Network

AbstractLarge-magnitude pressure signatures associated with a wide range of atmospheric phenomena (e.g., mesoscale gravity waves, convective complexes, tropical disturbances, and synoptic storm systems) are examined using a unique set of surface pressure sensors deployed as part of the National Science Foundation EarthScope USArray Transportable Array. As part of the USArray project, approximately 400 seismic stations were deployed in a pseudogrid fashion across a portion of the United States for 1–2 yr, then retrieved and redeployed farther east. Surface pressure observations at a sampling frequency of 1 Hz were examined during the period 1 January 2010–28 February 2014 when the seismic array was transitioning from the central to eastern continental United States. Surface pressure time series at over 900 locations were bandpass filtered to examine pressure perturbations on three temporal scales: meso- (10 min–4 h), subsynoptic (4–30 h), and synoptic (30 h–5 days) scales.Case studies of strong pressure pe...

Tracking Mesoscale Pressure Perturbations Using the USArray Transportable Array

AbstractMesoscale convective phenomena induce pressure perturbations that can alter the strength and magnitude of surface winds, precipitation, and other sensible weather, which, in some cases, can inflict injuries and damage to property. This work extends prior research to identify and characterize mesoscale pressure features using a unique resource of 1-Hz pressure observations available from the USArray Transportable Array (TA) seismic field campaign.A two-dimensional variational technique is used to obtain 5-km surface pressure analysis grids every 5 min from 1 March to 31 August 2011 from the TA observations and gridded surface pressure from the Real-Time Mesoscale Analysis over a swath of the central United States. Bandpass-filtering and feature-tracking algorithms are employed to isolate, identify, and assess prominent mesoscale pressure perturbations and their properties. Two case studies, the first involving mesoscale convective systems and the second using a solitary gravity wave, are analyzed u...

EarthScope USArray Transportable Array (TA) Surface Pressure Observations Sampled at 1 Hz Frequency

The EarthScope USArray Transportable Array (TA) contains over 400 seismic station platforms deployed in a pseudo-grid fashion (spaced approximately 70 km apart) across a portion of the United States. This array is part of a large initiative within the geoscience field to improve earth mapping and understanding of subsurface properties. Individual platforms report for 1 to 2 years and then are retrieved and redeployed farther east. Atmospheric pressure sensors were added to many platforms in 2010 while the array was deployed in the Central U.S. to assist with identification of seismic signals produced by atmospheric phenomena. These sensors have resulted in a tremendous dataset of surface pressure observations with high temporal frequency not commonly found in atmospheric sciences outside of smaller field campaigns.\n\nThis dataset provides surface pressure observations at 1 Hz frequency from these deployments beginning 1 January 2010. The years 2010-2011 feature deployments over the central U.S. Great Plains, 2012-2013 over the interior eastern U.S., and 2014-2015 along the U.S. east coast. While average station life is 1 to 2 years, some deployments have been kept in place and thus have longer records. Further, the next phase of the TA project has begun with several platforms deployed in Alaska, which will continue over the next few years. There are also deployments located near the Cascade Mountain range in the Pacific Northwest. Data files are provided in HDF5 format, where a single file contains data for a particular year and station. Basic metadata and quality control files are also available.

Evaluating the Experimental High-Resolution Rapid Refresh–Alaska Modeling System Using USArray Pressure Observations

AbstractThe High-Resolution Rapid Refresh–Alaska (HRRR-AK) modeling system provides 3-km horizontal resolution and 0–36-h forecast guidance for weather conditions over Alaska. This study evaluated ...

Exploring the evolution of pressure-perturbations to understand atmospheric phenomena

Atmospheric sciences is the study of physical and chemical phenomena occurring within the Earths atmosphere. The study entails understanding the state of the Earths atmosphere, how it is changing over time and why. Understanding how various weather events develop and evolve is often conducted through retrospective analysis of past atmospheric events. Atmospheric scientists can then utilize tools to better predict potential hazards and provide earlier warnings for events that may impact life and property. Several atmospheric state variables can be measured to identify high-impact events, one of which is surface atmospheric pressure. Many weather events are characterized by variations in surface pressure from the mean pressure value (i.e., pressure-perturbations). Accordingly, there is significant interest in extracting and tracking pressure-perturbations both spatially and temporally to better understand the evolution of weather events. Here, we present a visualization and analysis environment that allows interactive exploration of pressure-perturbation data sets. Our system, for the first time, enables atmospheric scientists to interactively explore the spatiotemporal behaviors of pressure-perturbations for a range of values and provides support to leverage other conventional data sets such as radar imagery and wind observations. It also allows atmospheric scientists to evaluate model and parameter sensitivity, which is difficult if not impossible with conventional visualization tools in atmospheric sciences. Finally, we demonstrate the utility of our approach for retrospective analysis using different case studies of recorded severe weather events.