Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 7 of 7

Full-Text Articles in Meteorology

A Case Study Of Stratospheric Ozone Transport To The Northern San Francisco Bay Area And Sacramento Valley During Cabots 2016, Jodie Clark, Sen Chiao Dec 2019

A Case Study Of Stratospheric Ozone Transport To The Northern San Francisco Bay Area And Sacramento Valley During Cabots 2016, Jodie Clark, Sen Chiao

Faculty Research, Scholarly, and Creative Activity

The California Baseline Ozone Transport Study (CABOTS) was a major air quality study that collected ozone measurements aloft between mid-May and mid-August of 2016. Aircraft measurements, ground-based lidar measurements, and balloon-borne ozonesondes collected precise upper-air ozone measurements across the central and Southern California valley. Utilizing daily ozonesonde data from Bodega Bay, California, and Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), reanalysis data for 25 July to 14 August 2016, three stratospheric intrusion events are identified over Northern California influencing air masses above Bodega Bay and Sacramento simultaneously. Calculated percent daily changes in afternoon ozonesonde observations indicate increasing …


The Intensification Of Hurricane Maria 2017 In The Antilles, Mark Jury, Sen Chiao, Raphael Cécé Oct 2019

The Intensification Of Hurricane Maria 2017 In The Antilles, Mark Jury, Sen Chiao, Raphael Cécé

Faculty Publications, Meteorology and Climate Science

Environmental influences on Hurricane Maria in the Antilles Islands are analyzed at the large-scale (1–25 September) and at the meso-scale (17–20 September 2017). The storm intensified rapidly prior to landfall in Dominica, going from category 1 to 5 in 15 h. As the storm progressed toward Puerto Rico (PR), its NE flank entrained air from seas cooled by the earlier passage of two hurricanes, and strengthened on its SW flank. Operational model forecasts tended to delay intensification until west of the Antilles Islands, thus motivating two independent weather research and forecasting (WRF) simulations. These gave minimal track errors at 1- …


Developing Spatially Accurate Rainfall Predictions For The San Francisco Bay Area Through Case Studies Of Atmospheric River And Other Synoptic Events, Alison Bridger, Dung Nguyen, Sen Chiao Sep 2019

Developing Spatially Accurate Rainfall Predictions For The San Francisco Bay Area Through Case Studies Of Atmospheric River And Other Synoptic Events, Alison Bridger, Dung Nguyen, Sen Chiao

Faculty Publications, Meteorology and Climate Science

Rainfall patterns in the San Francisco Bay Area (SFBA) are highly influenced by local topography. It has been a forecasting challenge for the main US forecast models. This study investigates the ability of the Weather Research and Forecasting (WRF) model to improve upon forecasts, with particular emphasis on the rain shadow common to the southern end of the SFBA. Three rain events were evaluated: a mid-season atmospheric river (AR) event with copious rains; a typical non-AR frontal passage rain event; and an area-wide rain event in which zero rain was recorded in the southern SFBA. The results show that, with …


Comparison Of Simulations Of Updraft Mass Fluxes And Their Response To Increasing Aerosol Concentration Between A Bin Scheme And A Bulk Scheme In A Deep-Convective Cloud System, Seoung Soo Lee, Chang-Hoon Jung, Sen Chiao, Junshik Um, Yong-Sang Choi, Won Jun Choi Jun 2019

Comparison Of Simulations Of Updraft Mass Fluxes And Their Response To Increasing Aerosol Concentration Between A Bin Scheme And A Bulk Scheme In A Deep-Convective Cloud System, Seoung Soo Lee, Chang-Hoon Jung, Sen Chiao, Junshik Um, Yong-Sang Choi, Won Jun Choi

Faculty Publications, Meteorology and Climate Science

Key microphysical processes whose parameterizations have substantial impacts on the simulation of updraft mass fluxes and their response to aerosol are investigated in this study. For this investigation, comparisons of these parameterizations are made between a bin scheme and a bulk scheme. These comparisons show that the differences in the prediction of cloud droplet number concentration (CDNC) between the two schemes determine whether aerosol-induced invigoration of updrafts or convection occurs. While the CDNC prediction leads to aerosol-induced invigoration of updrafts and an associated 20% increase in the peak value of the updraft-mass-flux vertical profile in the bin scheme, it leads …


Numerical Investigations Of Atmospheric Rivers And The Rain Shadow Over The Santa Clara Valley, Dalton Behringer, Sen Chiao Mar 2019

Numerical Investigations Of Atmospheric Rivers And The Rain Shadow Over The Santa Clara Valley, Dalton Behringer, Sen Chiao

Faculty Publications, Meteorology and Climate Science

This study investigated precipitation distribution patterns in association with atmospheric rivers (ARs). The Weather Research and Forecasting (WRF) model was employed to simulate two strong atmospheric river events. The precipitation forecasts were highly sensitive to cloud microphysics parameterization schemes. Thus, radar observed and simulated ZH and ZDR were evaluated to provide information about the drop-size distribution (DSD). Four microphysics schemes (WSM-5, WSM-6, Thompson, and WDM-6) with nested simulations (3 km, 1 km, and 1/3 km) were conducted. One of the events mostly contained bright-band (BB) rainfall and lasted less than 24 h, while the other contained both BB and non-bright-band …


The Fire And Smoke Model Evaluation Experiment—A Plan For Integrated, Large Fire–Atmosphere Field Campaigns, Susan Prichard, N. Sim Larkin, Roger Ottmar, Nancy H.F. French, Kirk Baker, Tim Brown, Craig B. Clements, Matt Dickinson, Andrew Hudak, Adam Kochanski, Rod Linn, Yongqiang Liu, Brian Potter, William Mell, Danielle Tanzer, Shawn Urbanski, Adam Watts Feb 2019

The Fire And Smoke Model Evaluation Experiment—A Plan For Integrated, Large Fire–Atmosphere Field Campaigns, Susan Prichard, N. Sim Larkin, Roger Ottmar, Nancy H.F. French, Kirk Baker, Tim Brown, Craig B. Clements, Matt Dickinson, Andrew Hudak, Adam Kochanski, Rod Linn, Yongqiang Liu, Brian Potter, William Mell, Danielle Tanzer, Shawn Urbanski, Adam Watts

Faculty Publications, Meteorology and Climate Science

The Fire and Smoke Model Evaluation Experiment (FASMEE) is designed to collect integrated observations from large wildland fires and provide evaluation datasets for new models and operational systems. Wildland fire, smoke dispersion, and atmospheric chemistry models have become more sophisticated, and next-generation operational models will require evaluation datasets that are coordinated and comprehensive for their evaluation and advancement. Integrated measurements are required, including ground-based observations of fuels and fire behavior, estimates of fire-emitted heat and emissions fluxes, and observations of near-source micrometeorology, plume properties, smoke dispersion, and atmospheric chemistry. To address these requirements the FASMEE campaign design includes a study …


Applications Of Satellite Data In Analyses Of Surface Pm2.5, Minghui Diao, Frank R. Freedman, Sen Chiao, Isa Cruz, Ana Rivera, Mohammad Z. Al-Hamdan, Akula Venkatram Jan 2019

Applications Of Satellite Data In Analyses Of Surface Pm2.5, Minghui Diao, Frank R. Freedman, Sen Chiao, Isa Cruz, Ana Rivera, Mohammad Z. Al-Hamdan, Akula Venkatram

Faculty Publications, Meteorology and Climate Science

Fine particulate is among the most harmful air pollutants for human health. There is ongoing interest in developing reliable methods to estimate PM2.5 concentrations 1) at unmonitored locations and 2) at finer horizontal resolution for improved health risk assessment and public health tracking.We aim to develop an efficient system that can reliably estimate PM2.5 at unmonitored locations and at finer horizontal resolution at important locations.• MODIS aerosol optical depth (AOD) provides an input for particulate levels at unmonitored locations in methods used to construct regional PM2.5 fields.• Dispersion model fields can be fused into portions of these regional fields for …