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San Jose State University

Faculty Publications, Meteorology and Climate Science

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Articles 1 - 30 of 80

Full-Text Articles in Physical Sciences and Mathematics

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- …

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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 …

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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 …

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Asian Long-Range Transport In Relation To Atmospheric Rivers In Northern California, Catherine Liu, Sen Chiao, Ju-Mee Ryoo Jun 2019

Asian Long-Range Transport In Relation To Atmospheric Rivers In Northern California, Catherine Liu, Sen Chiao, Ju-Mee Ryoo

Faculty Publications, Meteorology and Climate Science

The study investigates the effect of aerosol long-range transport on precipitation over Northern California during atmospheric river (AR) events in the 2017 cold season (January–April). ARs in 2017 were one of the strongest to date, and the intense precipitation associated with the ARs resulted in flooding, destruction of property, and contamination of water supplies. The Aerosol Optical Depth (AOD) from Moderate Resolution Imaging Spectroradiometer (MODIS) data shows Asian dust traveling across the Northern Pacific Ocean along with AR events. Aerosol measurements in California, provided by the Interagency Monitoring of Protected Visual Environments (IMPROVE), show that more Asian dust tends to …

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Cloud Phase And Relative Humidity Distributions Over The Southern Ocean In Austral Summer Based On In Situ Observations And Cam5 Simulations, John D’Alessandro, Minghui Diao, Chenglai Wu, Xiaohong Liu, Jorgen Jensen, Britton Stephens Apr 2019

Cloud Phase And Relative Humidity Distributions Over The Southern Ocean In Austral Summer Based On In Situ Observations And Cam5 Simulations, John D’Alessandro, Minghui Diao, Chenglai Wu, Xiaohong Liu, Jorgen Jensen, Britton Stephens

Faculty Publications, Meteorology and Climate Science

Cloud phase and relative humidity (RH) distributions at -67°–0°C over the Southern Ocean during austral summer are compared between in situ airborne observations and global climate simulations. A scale-aware comparison is conducted using horizontally averaged observations from 0.1–50 km. Cloud phase frequencies, RH distributions and liquid mass fraction are found less affected by horizontal resolutions than liquid and ice water content (LWC, IWC), liquid and ice number concentrations (Ncliq, Ncice), and ice supersaturation (ISS) frequency. At -10°–0°C, observations show 27%–34% and 17%–37% of liquid and mixed phases, while simulations show 60%–70% and 3%–4%, respectively. Simulations overestimate (underestimate) LWC and Ncliq …

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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 …

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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 …

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The Rapid Deployments To Wildfires Experiment (Radfire): Observations From The Fire Zone, Craig Clements, Neil Lareau, David Kingsmill, Carrie Bowers, Christopher Camacho, Richard Bagley, Braniff Davis Jan 2019

The Rapid Deployments To Wildfires Experiment (Radfire): Observations From The Fire Zone, Craig Clements, Neil Lareau, David Kingsmill, Carrie Bowers, Christopher Camacho, Richard Bagley, Braniff Davis

Faculty Publications, Meteorology and Climate Science

The Rapid Deployments to Wildfires Experiment (RaDFIRE) was a meteorological field campaign aimed at observing fire–atmosphere interactions during active wildfires. Using a rapidly deployable scanning Doppler lidar, airborne Doppler radar, and a suite of other instruments, the field campaign sampled 21 wildfires from 2013 to 2016 in the western United States. Observations include rotating convective plumes, plume interactions with stable layers and multilayered smoke detrainment, convective plume entrainment processes, smoke-induced density currents, and aircraft in situ observations of developing pyrocumulus. Collectively, these RaDFIRE observations highlight the range of meteorological phenomena associated with wildfires, especially plume dynamics, and will provide a …

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Air Quality And Health Burden Of 2017 Northern California Wildfires, Susan O’Neill, Minghui Diao Jan 2019

Air Quality And Health Burden Of 2017 Northern California Wildfires, Susan O’Neill, Minghui Diao

Faculty Publications, Meteorology and Climate Science

No abstract provided.

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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 …

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Calibration Of The Vertical Cavity Surface Emitting Laser (Vcsel) Water Vapor Hydrometer, Minghui Diao Nov 2018

Calibration Of The Vertical Cavity Surface Emitting Laser (Vcsel) Water Vapor Hydrometer, Minghui Diao

Faculty Publications, Meteorology and Climate Science

No abstract provided.

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Surf: Understanding And Predicting Urban Convection And Haze, X. Liang, S. Miao, J. Li, R. Bornstein, X. Zhang, Y. Gao, F. Chen, X. Cao, Z. Cheng, Craig Clements, W. Dabberdt, A. Ding, D. Ding, J. J. Dou, J.X. Dou, Y. Dou, C.S.B. Grimmond, J. E. González-Cruz, J. He, M. Huang, X. Huang, S. Ju, Q. Li, D. Niyogi, J. Quan, J. Sun, J.Z. Sun, M. Yu, J. Zhang, Y. Zhang, X. Zhao, Z. Zheng, M. Zhou Jul 2018

Surf: Understanding And Predicting Urban Convection And Haze, X. Liang, S. Miao, J. Li, R. Bornstein, X. Zhang, Y. Gao, F. Chen, X. Cao, Z. Cheng, Craig Clements, W. Dabberdt, A. Ding, D. Ding, J. J. Dou, J.X. Dou, Y. Dou, C.S.B. Grimmond, J. E. González-Cruz, J. He, M. Huang, X. Huang, S. Ju, Q. Li, D. Niyogi, J. Quan, J. Sun, J.Z. Sun, M. Yu, J. Zhang, Y. Zhang, X. Zhao, Z. Zheng, M. Zhou

Faculty Publications, Meteorology and Climate Science

Urbanization modifies atmospheric energy and moisture balances, forming distinct features [e.g., urban heat islands (UHIs) and enhanced or decreased precipitation]. These produce significant challenges to science and society, including rapid and intense flooding, heat waves strengthened by UHIs, and air pollutant haze. The Study of Urban Impacts on Rainfall and Fog/Haze (SURF) has brought together international expertise on observations and modeling, meteorology and atmospheric chemistry, and research and operational forecasting. The SURF overall science objective is a better understanding of urban, terrain, convection, and aerosol interactions for improved forecast accuracy. Specific objectives include a) promoting cooperative international research to improve …

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Using Satellite-Derived Pm2.5 Dataset To Assist Air Pollution Management In California, Minghui Diao, Frank Freedman, Sen Chiao, Ana Rivera Jul 2018

Using Satellite-Derived Pm2.5 Dataset To Assist Air Pollution Management In California, Minghui Diao, Frank Freedman, Sen Chiao, Ana Rivera

Faculty Publications, Meteorology and Climate Science

No abstract provided.

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The O2/N2 Ratio And Co2 Airborne Southern Ocean Study, Britton Stephens, Matthew Long, Ralph Keeling, Eric Kort, Colm Sweeney, Eric Apel, Elliot Atlas, Stuart Beaton, Jonathan Bent, Nicola Blake, James Bresch, Joanna Casey, Bruce Daube, Minghui Diao, Ernesto Diaz, Heidi Dierssen, Valeria Donets, Bo-Cai Gao, Michelle Gierach, Robert Green, Justin Haag, Matthew Hayman, Alan Hills, Martín Hoecker-Martínez, Shawn Honomichl, Rebecca Hornbrook, Jorgen Jensen, Rong-Rong Li, Ian Mccubbin, Kathryn Mckain, Eric Morgan, Scott Nolte, Jordan Powers, Bryan Rainwater, Kaylan Randolph, Mike Reeves, Sue Schauffler, Katherine Smith, Mackenzie Smith, Jeff Stith, Gregory Stossmeister, Darin Toohey, Andrew Watt Feb 2018

The O2/N2 Ratio And Co2 Airborne Southern Ocean Study, Britton Stephens, Matthew Long, Ralph Keeling, Eric Kort, Colm Sweeney, Eric Apel, Elliot Atlas, Stuart Beaton, Jonathan Bent, Nicola Blake, James Bresch, Joanna Casey, Bruce Daube, Minghui Diao, Ernesto Diaz, Heidi Dierssen, Valeria Donets, Bo-Cai Gao, Michelle Gierach, Robert Green, Justin Haag, Matthew Hayman, Alan Hills, Martín Hoecker-Martínez, Shawn Honomichl, Rebecca Hornbrook, Jorgen Jensen, Rong-Rong Li, Ian Mccubbin, Kathryn Mckain, Eric Morgan, Scott Nolte, Jordan Powers, Bryan Rainwater, Kaylan Randolph, Mike Reeves, Sue Schauffler, Katherine Smith, Mackenzie Smith, Jeff Stith, Gregory Stossmeister, Darin Toohey, Andrew Watt

Faculty Publications, Meteorology and Climate Science

The Southern Ocean plays a critical role in the global climate system by mediating atmosphere–ocean partitioning of heat and carbon dioxide. However, Earth system models are demonstrably deficient in the Southern Ocean, leading to large uncertainties in future air–sea CO2 flux projections under climate warming and incomplete interpretations of natural variability on interannual to geologic time scales. Here, we describe a recent aircraft observational campaign, the O2/N2 Ratio and CO2 Airborne Southern Ocean (ORCAS) study, which collected measurements over the Southern Ocean during January and February 2016. The primary research objective of the ORCAS campaign was to improve observational constraints …

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Hurricane Fred (2015): Cape Verde's First Hurricane In Modern Times: Observations, Impacts, And Lessons Learned, Gregory Jenkins, Ester Brito, Emanuel Soares, Sen Chiao, Jose Lima, Benvendo Tavares, Angelo Cardoso, Francisco Evora, Maria Monteiro Jan 2018

Hurricane Fred (2015): Cape Verde's First Hurricane In Modern Times: Observations, Impacts, And Lessons Learned, Gregory Jenkins, Ester Brito, Emanuel Soares, Sen Chiao, Jose Lima, Benvendo Tavares, Angelo Cardoso, Francisco Evora, Maria Monteiro

Faculty Publications, Meteorology and Climate Science

During 31 August 2015, Hurricane Fred traversed through the Cape Verde islands, passing near Boa Vista and possibly making landfall over São Nicolau during the evening hours. Hurricane Fred was a category 1 storm with maximum winds of 75 kt and a sea level pressure of 986 hPa during 31 August. The African easterly wave associated with Tropical Cyclone (TC) Fred emerged from Guinea on 29 August and was named Tropical Storm Fred on 30 August. Prior to impacting Cape Verde, the storm caused the sinking of a ship and the loss of seven lives off the coast of Guinea-Bissau …

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Ice Nucleation Parameterization And Relative Humidity Distribution In Idealized Squall-Line Simulations, Minghui Diao, George Bryan, Hugh Morrison, Jorgen Jensen Sep 2017

Ice Nucleation Parameterization And Relative Humidity Distribution In Idealized Squall-Line Simulations, Minghui Diao, George Bryan, Hugh Morrison, Jorgen Jensen

Faculty Publications, Meteorology and Climate Science

Output from idealized simulations of a squall line are compared with in situ aircraft-based observations from the Deep Convective Clouds and Chemistry campaign. Relative humidity distributions around convection are compared between 1-Hz aircraft observations (≈250-m horizontal scale) and simulations using a double-moment bulk microphysics scheme at three horizontal grid spacings: Δx = 0.25, 1, and 4 km. The comparisons focus on the horizontal extent of ice supersaturated regions (ISSRs), the maximum and average relative humidity with respect to ice (RHi) in ISSRs, and the ice microphysical properties during cirrus cloud evolution, with simulations at 0.25 and 1 km providing better …

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The Mean And Turbulent Properties Of A Wildfire Convective Plume, Neil Lareau, Craig Clements Aug 2017

The Mean And Turbulent Properties Of A Wildfire Convective Plume, Neil Lareau, Craig Clements

Faculty Publications, Meteorology and Climate Science

The time-mean and time-varying smoke and velocity structure of a wildfire convective plume is examined using a high-resolution scanning Doppler lidar. The mean plume is shown to exhibit the archetypal form of a bent-over plume in a crosswind, matching the well-established Briggs plume-rise equation. The plume cross section is approximately Gaussian and the plume radius increases linearly with height, consistent with plumerise theory. The Briggs plume-rise equation is subsequently inverted to estimate the mean fire-generated sensible heat flux, which is found to be 87 kW m22 . The mean radial velocity structure of the plume indicates flow convergence into the …

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Direct Comparisons Of Ice Cloud Macro- And Microphysical Properties Simulated By The Community Atmosphere Model Version 5 With Hippo Aircraft Observations, Chenglai Wu, Xiaohong Liu, Minghui Diao, Kai Zhang, Andrew Gettelman, Zheng Lu, Joyce Penner, Zhaohui Lin Apr 2017

Direct Comparisons Of Ice Cloud Macro- And Microphysical Properties Simulated By The Community Atmosphere Model Version 5 With Hippo Aircraft Observations, Chenglai Wu, Xiaohong Liu, Minghui Diao, Kai Zhang, Andrew Gettelman, Zheng Lu, Joyce Penner, Zhaohui Lin

Faculty Publications, Meteorology and Climate Science

In this study we evaluate cloud properties simulated by the Community Atmosphere Model version 5 (CAM5) using in situ measurements from the HIAPER Pole-to-Pole Observations (HIPPO) campaign for the period of 2009 to 2011. The modeled wind and temperature are nudged towards reanalysis. Model results collocated with HIPPO flight tracks are directly compared with the observations, and model sensitivities to the representations of ice nucleation and growth are also examined. Generally, CAM5 is able to capture specific cloud systems in terms of vertical configuration and horizontal extension. In total, the model reproduces 79.8 % of observed cloud occurrences inside model …

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Dynamical Conditions Of Ice Supersaturation And Ice Nucleation In Convective Systems: A Comparative Analysis Between In Situ Aircraft Observations And Wrf Simulations, John D'Alessandro, Minghui Diao, Chenglai Wu, Xiaohong Liu, Ming Chen, Hugh Morrison, Trude Eidhammer, Jorgen Jensen, Aaron Bansemer, Mark Zondlo, Joshua Digangi Mar 2017

Dynamical Conditions Of Ice Supersaturation And Ice Nucleation In Convective Systems: A Comparative Analysis Between In Situ Aircraft Observations And Wrf Simulations, John D'Alessandro, Minghui Diao, Chenglai Wu, Xiaohong Liu, Ming Chen, Hugh Morrison, Trude Eidhammer, Jorgen Jensen, Aaron Bansemer, Mark Zondlo, Joshua Digangi

Faculty Publications, Meteorology and Climate Science

Occurrence frequency and dynamical conditions of ice supersaturation (ISS, where relative humidity with respect to ice (RHi) > 100%) are examined in the upper troposphere around convective activity. Comparisons are conducted between in situ airborne observations and the Weather Research and Forecasting model simulations using four double‐moment microphysical schemes at temperatures ≤ −40°C. All four schemes capture both clear‐sky and in‐cloud ISS conditions. However, the clear‐sky (in‐cloud) ISS conditions are completely (significantly) limited to the RHi thresholds of the Cooper parameterization. In all of the simulations, ISS occurrence frequencies are higher by ~3–4 orders of magnitude at higher updraft speeds ( …

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Assessment Of An Atmospheric Transport Model For Annual Inverse Estimates Of California Greenhouse Gas Emissions, Justin Bagley, Seongeun Jeong, Xinguang Cui, Sally Newman, Jingsong Zhang, Chad Priest, Mixtli Campos-Pineda, Arlyn Andrews, Laura Bianco, Matthew Lloyd, Neil Lareau, Craig Clements, Marc Fischer Feb 2017

Assessment Of An Atmospheric Transport Model For Annual Inverse Estimates Of California Greenhouse Gas Emissions, Justin Bagley, Seongeun Jeong, Xinguang Cui, Sally Newman, Jingsong Zhang, Chad Priest, Mixtli Campos-Pineda, Arlyn Andrews, Laura Bianco, Matthew Lloyd, Neil Lareau, Craig Clements, Marc Fischer

Faculty Publications, Meteorology and Climate Science

Atmospheric inverse estimates of gas emissions depend on transport model predictions, hence driving a need to assess uncertainties in the transport model. In this study we assess the uncertainty in WRF-STILT (Weather Research and Forecasting and Stochastic Time-Inverted Lagrangian Transport) model predictions using a combination of meteorological and carbon monoxide (CO) measurements. WRF configurations were selected to minimize meteorological biases using meteorological measurements of winds and boundary layer depths from surface stations and radar wind profiler sites across California. We compare model predictions with CO measurements from four tower sites in California from June 2013 through May 2014 to assess …

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Estimating Methane Emissions From Biological And Fossil-Fuel Sources In The San Francisco Bay Area, Seongeun Jeong, Xinguang Cui, Donald Blake, Ben Miller, Stephen Montzka, Arlyn Andrews, Abhinav Guha, Philip Martien, Ray Bambha, Brian Lafranchi, Hope Michelsen, Craig Clements, Pierre Glaize, Marc Fischer Jan 2017

Estimating Methane Emissions From Biological And Fossil-Fuel Sources In The San Francisco Bay Area, Seongeun Jeong, Xinguang Cui, Donald Blake, Ben Miller, Stephen Montzka, Arlyn Andrews, Abhinav Guha, Philip Martien, Ray Bambha, Brian Lafranchi, Hope Michelsen, Craig Clements, Pierre Glaize, Marc Fischer

Faculty Publications, Meteorology and Climate Science

We present the first sector-specific analysis of methane (CH4) emissions from the San Francisco Bay Area (SFBA) using CH4 and volatile organic compound (VOC) measurements from six sites during September – December 2015. We apply a hierarchical Bayesian inversion to separate the biological from fossil-fuel (natural gas and petroleum) sources using the measurements of CH4 and selected VOCs, a source-specific 1 km CH4 emission model, and an atmospheric transport model. We estimate that SFBA CH4 emissions are 166–289 Gg CH4/yr (at 95% confidence), 1.3–2.3 times higher than a recent inventory with much of the underestimation from landfill. Including the VOCs, …

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Extending Flood Forecasting Lead Time In A Large Watershed By Coupling Wrf Qpf With A Distributed Hydrological Model, Ji Li, Yangbo Chen, Huanyu Wang, Jianming Qin, Jie Li, Sen Chiao Jan 2017

Extending Flood Forecasting Lead Time In A Large Watershed By Coupling Wrf Qpf With A Distributed Hydrological Model, Ji Li, Yangbo Chen, Huanyu Wang, Jianming Qin, Jie Li, Sen Chiao

Faculty Publications, Meteorology and Climate Science

Long lead time flood forecasting is very important for large watershed flood mitigation as it provides more time for flood warning and emergency responses. The latest numerical weather forecast model could provide 1–15-day quantitative precipitation forecasting products in grid format, and by coupling this product with a distributed hydrological model could produce long lead time watershed flood forecasting products. This paper studied the feasibility of coupling the Liuxihe model with the Weather Research and Forecasting quantitative precipitation forecast (WRF QPF) for large watershed flood forecasting in southern China. The QPF of WRF products has three lead times, including 24, 48 …

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An Assessment Of The Radiative Effects Of Ice Supersaturation Based On In Situ Observations, Xiaoxiao Tan, Yi Huang, Minghui Diao, Aaron Bansemer, Mark Zondlo, Joshua Digangi, Rainer Volkamer, Yongyun Hu Oct 2016

An Assessment Of The Radiative Effects Of Ice Supersaturation Based On In Situ Observations, Xiaoxiao Tan, Yi Huang, Minghui Diao, Aaron Bansemer, Mark Zondlo, Joshua Digangi, Rainer Volkamer, Yongyun Hu

Faculty Publications, Meteorology and Climate Science

We use aircraft observations combined with the reanalysis data to investigate the radiative effects of ice supersaturation (ISS). Our results show that although the excess water vapor over ice saturation itself has relatively small radiative effects, mistaking it as ice crystals in climate models would lead to considerable impacts: on average, +2.49 W/m2 change in the top of the atmosphere (TOA) radiation, −2.7 W/m2 change in surface radiation, and 1.47 K/d change in heating rates. The radiative effects of ISS generally increase with the magnitudes of supersaturation. However, there is a strong dependence on the preexisting ice water path, which …

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Environmental Controls On Pyrocumulus And Pyrocumulonimbus Initiation And Development, Neil Lareau, Craig Clements Jan 2016

Environmental Controls On Pyrocumulus And Pyrocumulonimbus Initiation And Development, Neil Lareau, Craig Clements

Faculty Publications, Meteorology and Climate Science

In this paper we present the first direct observational evidence that the condensation level in pyrocumulus and pyrocumulonimbus clouds can be significantly higher than the ambient lifted condensation level. In addition, we show that the environmental thermodynamic profile, day-to-day variations in humidity, and ambient wind shear all exert significant influence over the onset and development of pyroconvective clouds. These findings are established using a scanning Doppler lidar and mobile radiosonde system during two large wildfires in northern California, the Bald Fire and the Rocky Fire. The lidar is used to distinguish liquid water from smoke backscatter during the plume rise, …

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Topography And Tropical Cyclone Structure Influence On Eyewall Evolution In Typhoon Sinlaku (2008), Cheng-Hsiang Chih, Kun-Hsuan Chou, Sen Chiao Oct 2015

Topography And Tropical Cyclone Structure Influence On Eyewall Evolution In Typhoon Sinlaku (2008), Cheng-Hsiang Chih, Kun-Hsuan Chou, Sen Chiao

Faculty Publications, Meteorology and Climate Science

Typhoon Sinlaku (2008) was a tropical system that affected many countries in East Asia. Besides the loss of life and economic damage, many scientific questions are associated with this system that need to be addressed. A series of numerical simulations were conducted in this study using V3.2 of the advanced research version of the Weather Research and Forecasting (WRF-ARW) model to examine the impacts of different terrain conditions and vortex structures on the eyewall evolution when Sinlaku was crossing Taiwan. The sensitivity experiments using different vortex structures show that a storm of the same intensity with a larger eyewall radius …

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Comparisons Of Cirrus Cloud Properties Between Polluted And Pristine Air Based On In-Situ Observations From The Nasa Attrex, Nsf Hippo And Eu Inca Campaigns, Minghui Diao, Jorgen Jensen Jul 2015

Comparisons Of Cirrus Cloud Properties Between Polluted And Pristine Air Based On In-Situ Observations From The Nasa Attrex, Nsf Hippo And Eu Inca Campaigns, Minghui Diao, Jorgen Jensen

Faculty Publications, Meteorology and Climate Science

Cirrus clouds, covering about 30% of the Earth’s surface area, play an important role in the climate and weather systems. Cirrus cloud radiative forcing (cooling or warming) is influenced by their microphysical (e.g., ice crystal number concentration and size distribution) and macroscopic (e.g., spatial extent) properties. Currently it is still unclear how the formation of cirrus clouds and their microphysical properties are influenced by anthropogenic emissions. In this work, we use in-situ observations from three flight campaigns to compare the cirrus cloud properties between polluted and pristine regions. Our dataset includes: (1) the NASA Airborne Tropical Tropopause Experiment (ATTREX) campaign …

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Distributions Of Ice Supersaturation And Ice Crystals From Airborne Observations In Relation To Upper Tropospheric Dynamical Boundaries, Minghui Diao, Jorgen Jensen, Laura Pan, Cameron Homeyer, Shawn Honomichl, James Bresch, Aaron Bansemer May 2015

Distributions Of Ice Supersaturation And Ice Crystals From Airborne Observations In Relation To Upper Tropospheric Dynamical Boundaries, Minghui Diao, Jorgen Jensen, Laura Pan, Cameron Homeyer, Shawn Honomichl, James Bresch, Aaron Bansemer

Faculty Publications, Meteorology and Climate Science

Ice supersaturation (ISS) is the prerequisite condition for cirrus cloud formation. To examine multiscale dynamics' influences on ISS formation, we analyze in situ aircraft observations (~200 m scale) over North America in coordinates relative to dynamical boundaries in the upper troposphere and lower stratosphere. Two case studies demonstrate that ISS formation is likely influenced by mesoscale uplifting, small-scale waves, and turbulence. A collective analysis of 15 flights in April–June 2008 shows that the top layers of ISS and ice crystal distributions are strongly associated with thermal tropopause height. In addition, the average occurrence frequencies of ISS and ice crystals on …

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Comparing The Model-Simulated Global Warming Signal To Observations Using Empirical Estimates Of Unforced Noise, Patrick T. Brown, Wenhong Li, Eugene C. Cordero, Steven A. Mauget Apr 2015

Comparing The Model-Simulated Global Warming Signal To Observations Using Empirical Estimates Of Unforced Noise, Patrick T. Brown, Wenhong Li, Eugene C. Cordero, Steven A. Mauget

Faculty Publications, Meteorology and Climate Science

The comparison of observed global mean surface air temperature (GMT) change to the mean change simulated by climate models has received much public and scientific attention. For a given global warming signal produced by a climate model ensemble, there exists an envelope of GMT values representing the range of possible unforced states of the climate system (the Envelope of Unforced Noise; EUN). Typically, the EUN is derived from climate models themselves, but climate models might not accurately simulate the correct characteristics of unforced GMT variability. Here, we simulate a new, empirical, EUN that is based on instrumental and reconstructed surface …

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Cold Smoke: Smoke-Induced Density Currents Cause Unexpected Smoke Transport Near Large Wildfires, Neil Lareau, Craig Clements Jan 2015

Cold Smoke: Smoke-Induced Density Currents Cause Unexpected Smoke Transport Near Large Wildfires, Neil Lareau, Craig Clements

Faculty Publications, Meteorology and Climate Science

The first observations of smoke-induced density currents originating from large wildfires are presented. Using a novel mobile Doppler lidar and additional in situ measurements, we document a deep (~ 2 km) smoke-filled density current that propagates more than 25 km at speeds up to 4.5 m s−1 near a large forest fire in northern California. Based on these observations we show that the dynamics governing the spread of the smoke layer result from differential solar heating between the smoke-filled and smoke-free portions of the atmospheric boundary layer. A calculation of the theoretical density current speed agrees well with the observed …

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Observations Of Fire-Induced Turbulence Regimes During Low-Intensity Wildland Fires In Forested Environments: Implications For Smoke Dispersion, Warren Heilman, Craig Clements, Daisuke Seto, Xindi Bian, Kenneth Clark, Nicholas Skowronski, John Hom Jan 2015

Observations Of Fire-Induced Turbulence Regimes During Low-Intensity Wildland Fires In Forested Environments: Implications For Smoke Dispersion, Warren Heilman, Craig Clements, Daisuke Seto, Xindi Bian, Kenneth Clark, Nicholas Skowronski, John Hom

Faculty Publications, Meteorology and Climate Science

Low-intensity wildland fires occurring beneath forest canopies can result in particularly adverse local air-quality conditions. Ambient and fire-induced turbulent circulations play a substantial role in the transport and dispersion of smoke during these fire events. Recent in situ measurements of fire–atmosphere interactions during low-intensity wildland fires have provided new insight into the structure of fire-induced turbulence regimes and how forest overstory vegetation can affect the horizontal and vertical dispersion of smoke. In this paper, we provide a summary of the key turbulence observations made during two low-intensity wildland fire events that occurred in the New Jersey Pine Barrens.

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