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Meteorology

San Jose State University

2013

Articles 1 - 7 of 7

Full-Text Articles in Physical Sciences and Mathematics

Ice Crystal Formation And Evolution In Five Campaigns: Start08, Hippo Global, Dc3, Predict And Torero, Minghui Diao, Joshua Digangi, Anthony O’Brien, Mark Zondlo Dec 2013

Ice Crystal Formation And Evolution In Five Campaigns: Start08, Hippo Global, Dc3, Predict And Torero, Minghui Diao, Joshua Digangi, Anthony O’Brien, Mark Zondlo

Faculty Publications, Meteorology and Climate Science

In order to understand the microphysical properties of cirrus clouds, it is important to understand the formation and evolution of the environments where ice crystals form and reside on the microscale (~100 m). Uncertainties remain in simulating/parameterizing the evolution of ice crystals, which require more analyses in the Lagrangian view. However, most in situ observations are in the Eulerian view and are restricted from examining the lifecycle of cirrus clouds. In this work, a new method of Diao et al. GRL (2013)* is used to separate out five phases of ice crystal evolution, using the horizontal spatial relationships between ice …

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Evolution Of Ice Crystal Regions On The Microscale Based On In Situ Observations, Minghui Diao, Mark Zondlo, Andrew Heymsfield, Stuart Beaton, David Rogers Jul 2013

Evolution Of Ice Crystal Regions On The Microscale Based On In Situ Observations, Minghui Diao, Mark Zondlo, Andrew Heymsfield, Stuart Beaton, David Rogers

Faculty Publications, Meteorology and Climate Science

[1] Microphysical properties of cirrus clouds largely influence their atmospheric radiative forcing. However, uncertainties remain in simulating/parameterizing the evolution of ice crystals. These uncertainties require more analyses in the Lagrangian view, yet most in situ observations are in the Eulerian view. Here we demonstrate a new method to separate out five phases of ice crystal evolution, using the horizontal spatial relationships between ice supersaturated regions (ISSRs) and ice crystal regions (ICRs). Based on global in situ data sets, we show that the samples of clear-sky ISSRs, ice crystal formation/growth, and evaporation/sedimentation are ~20%, 10%, and 70% of the total ISSR …

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Validation Of Airs/Amsu - A Water Vapor And Temperature Data With In Situ Aircraft Observations From The Surface To Ut/Ls From 87°N–67°S, Minghui Diao, Loayeh Jumbam, Justin Sheffield, Eric Wood, Mark Zondlo Jun 2013

Validation Of Airs/Amsu - A Water Vapor And Temperature Data With In Situ Aircraft Observations From The Surface To Ut/Ls From 87°N–67°S, Minghui Diao, Loayeh Jumbam, Justin Sheffield, Eric Wood, Mark Zondlo

Faculty Publications, Meteorology and Climate Science

[1] Validation of the Atmospheric Infrared Sounder (AIRS)/Advanced Microwave Sounding Unit (AMSU-A) data set with in situ observations provides useful information on its application to climate and weather studies. However, different space/time averaging windows have been used in past studies, and questions remain on the variation of errors in space, such as between land/ocean and the Northern/Southern Hemispheres. In this study, in situ aircraft measurements of water vapor and temperature are compared with the AIRS/AMSU-A retrievals (Version 5 Level 2) from 87°N to 67°S and from the surface to the upper troposphere and lower stratosphere (UT/LS). By using a smaller …

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Leeside Boundary Layer Confluence And Afternoon Thunderstorms Over Mayaguez, Puerto Rico, Mark Jury, Sen Chiao Feb 2013

Leeside Boundary Layer Confluence And Afternoon Thunderstorms Over Mayaguez, Puerto Rico, Mark Jury, Sen Chiao

Faculty Publications, Meteorology and Climate Science

The midsummer boundary layer (BL) circulation and afternoon thunderstorm convection on the lee side of Puerto Rico is studied using observations and high-resolution models. Satellite infrared data help to identify cases on 5 and 14 June 2010 when midday surface temperatures show a 2°C gradient between land and sea and afternoon cloud-top temperatures <−60°C. Acoustic sounder profiles are analyzed for climatology, wind shear, turbulence, and diurnal cycles in the 40-300-m layer. Weather Research and Forecasting (WRF) model simulations indicate that sea-breeze flow is entrained into convective cells near Mayaguez, Puerto Rico. The simulated BL wind shear is too weak (0.5 × 10−2 s−1) in comparison with the acoustic sounder (2 × 10−2 s−1). Model 900-hPa winds are southeasterly and spread simulated convection too far north in comparison with radar. The pattern of near-surface winds in the island wake triggers afternoon thunderstorms near Mayaguez. A feature of the confluent circulation around Puerto Rico is opposing shear zones on the leeward corners of the island and a sea breeze of 5 m s−1 over the west coast during midday. [ABSTRACT FROM AUTHOR] . Copyright of Journal of Applied Meteorology & Climatology is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.).

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Evaluation Of Wrf-Sfire Performance With Field Observations From The Fireflux Experiment, A. Kochanski, M. Jenkins, J. Mandel, J. Beezley, Craig Clements, S. Krueger Jan 2013

Evaluation Of Wrf-Sfire Performance With Field Observations From The Fireflux Experiment, A. Kochanski, M. Jenkins, J. Mandel, J. Beezley, Craig Clements, S. Krueger

Faculty Publications, Meteorology and Climate Science

This study uses in situ measurements collected during the FireFlux field experiment to evaluate and improve the performance of the coupled atmosphere–fire model WRF-SFIRE. The simulation by WRF-SFIRE of the experimental burn shows that WRF-SFIRE is capable of providing realistic head-fire rate of spread and vertical temperature structure of the fire plume, and fire-induced surface flow and vertical velocities within the plume up to 10 m above ground level. The simulation captured the changes in wind speed and direction before, during, and after fire front passage, along with the arrival times of wind speed, temperature, and updraft maxima, at the …

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Kinematic Structure Of A Wildland Fire Plume Observed By Doppler Lidar, A. Charland, Craig Clements Jan 2013

Kinematic Structure Of A Wildland Fire Plume Observed By Doppler Lidar, A. Charland, Craig Clements

Faculty Publications, Meteorology and Climate Science

Wildland fires present a challenging environment to make meteorological measurements. Observations in the vicinity of wildland fires are needed to better understand fire-atmosphere interactions and to provide data for the evaluation of coupled fire-atmosphere models. An observational study was conducted during a low-intensity prescribed fire in an area of complex terrain with grass fuels east of San José, California. A ground-based scanning Doppler lidar acquired radial wind velocities and backscatter intensity in and around the fire plume from multiple horizontal and vertical scans. The development of a convergence zone was consistently observed to exist downwind of the plume and was …

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Numerical Investigations Of Convective Initiation In Barbados, Kim Whitehall, Sen Chiao, Margarette Mayers-Als Jan 2013

Numerical Investigations Of Convective Initiation In Barbados, Kim Whitehall, Sen Chiao, Margarette Mayers-Als

Faculty Publications, Meteorology and Climate Science

Localized convection in Barbados accounts for hazardous conditions and a significant percentage of the island’s annual rainfall. The feature results in rainfall accumulations exceeding 50 mm in 3 hours or less, over isolated locations. Weather Research and Forecasting model (WRF) simulations are conducted for a rapid convective initiated and heavy precipitation event of 26 August 2008 over Barbados. The simulation results from the 1 km grid resolution domain depict that the shallow topography on the island plays a significant role in enhancing convective activity under weak synoptically disturbed conditions. The model results also demonstrate that the driving forces for the …

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