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Articles 1 - 30 of 58
Full-Text Articles in Climate
The Intensification Of Hurricane Maria 2017 In The Antilles, Mark Jury, Sen Chiao, Raphael Cécé
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
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 …
Numerical Investigations Of Atmospheric Rivers And The Rain Shadow Over The Santa Clara Valley, Dalton Behringer, Sen Chiao
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 …
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
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 …
Calibration Of The Vertical Cavity Surface Emitting Laser (Vcsel) Water Vapor Hydrometer, Minghui Diao
Calibration Of The Vertical Cavity Surface Emitting Laser (Vcsel) Water Vapor Hydrometer, Minghui Diao
Faculty Publications, Meteorology and Climate Science
No abstract provided.
Using Satellite-Derived Pm2.5 Dataset To Assist Air Pollution Management In California, Minghui Diao, Frank Freedman, Sen Chiao, Ana Rivera
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.
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
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 …
The Mean And Turbulent Properties Of A Wildfire Convective Plume, Neil Lareau, Craig Clements
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 …
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
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 …
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
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 ( …
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
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 …
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
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, …
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
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 …
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
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 …
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
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 …
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
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 …
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, Eric Jensen
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, Eric Jensen
Faculty Publications, Meteorology and Climate Science
Cirrus clouds are one of the largest sources of uncertainties in predicting future climate. Ice nucleation and ice crystal growth inside cirrus clouds require ice supersaturation (ISS). Previously, remote sensing observations have shown that the locations of cirrus clouds’ cloud top height are highly correlated with the thermal tropopause height (Pan and Munchak, 2011). However, it is unclear if the initial conditions of cirrus clouds – ice supersaturated region (ISSRs) – have similar features in the extratropical upper troposphere and lower stratosphere (UT/LS). In fact, the dynamical processes and conditions that contribute to ISS formation from the microscale (~100 m) …
Optimal Ranking Regime Analysis Of Intra- To Multidecadal U.S. Climate Variability. Part I: Temperature, Eugene C. Cordero, Steven A. Mauget
Optimal Ranking Regime Analysis Of Intra- To Multidecadal U.S. Climate Variability. Part I: Temperature, Eugene C. Cordero, Steven A. Mauget
Faculty Publications, Meteorology and Climate Science
The optimal ranking regime (ORR) method was used to identify intradecadal to multidecadal (IMD) time windows containing significant ranking sequences in U.S. climate division temperature data. The simplicity of the ORR procedure’s output—a time series’ most significant nonoverlapping periods of high or low rankings—makes it possible to graphically identify common temporal breakpoints and spatial patterns of IMD variability in the analyses of 102 climate division temperature series. This approach is also applied to annual Atlantic multidecadal oscillation (AMO) and Pacific decadal oscillation (PDO) climate indices, a Northern Hemisphere annual temperature (NHT) series, and divisional annual and seasonal temperature data during …
Optimal Ranking Regime Analysis Of Intra- To Multidecadal U.S. Climate Variability. Part Ii: Precipitation And Streamflow, Steven A. Mauget, Eugene C. Cordero
Optimal Ranking Regime Analysis Of Intra- To Multidecadal U.S. Climate Variability. Part Ii: Precipitation And Streamflow, Steven A. Mauget, Eugene C. Cordero
Faculty Publications, Meteorology and Climate Science
In Part I of this paper, the optimal ranking regime (ORR) method was used to identify intradecadal to multidecadal (IMD) regimes in U.S. climate division temperature data during 1896–2012. Here, the method is used to test for annual and seasonal precipitation regimes during that same period. Water-year mean streamflow rankings at 125 U.S. Hydro-Climatic Data Network gauge stations are also evaluated during 1939–2011. The precipitation and streamflow regimes identified are compared with ORR-derived regimes in the Pacific decadal oscillation (PDO), the Atlantic multidecadal oscillation (AMO), and indices derived from gridded SST anomaly (SSTA) analysis data. Using a graphic display approach …
Hemispheric Comparison Of Cirrus Cloud Evolution Using In Situ Measurements In Hiaper Pole-To-Pole Observations, Minghui Diao, Mark Zondlo, Andrew Heymsfield, Stuart Beaton
Hemispheric Comparison Of Cirrus Cloud Evolution Using In Situ Measurements In Hiaper Pole-To-Pole Observations, Minghui Diao, Mark Zondlo, Andrew Heymsfield, Stuart Beaton
Faculty Publications, Meteorology and Climate Science
The radiative forcing of cirrus clouds is highly sensitive to their microphysical properties as well as their evolution. However, there are very limited observations and analyses on the cirrus cloud formation and evolution with both microscale resolution and global scale coverage. The lack of such observations limits the overall comparison of cirrus cloud evolution between the two hemispheres. In fact, the previous hemispheric comparisons of cirrus cloud microphysics using in situ observations were only based on the sampling over two locations at 55°N and 55°S (Ovarlez et al., 2002; Gayet et al., 2004). Here we use a more comprehensive aircraft-based …
Cloud-Scale Ice-Supersaturated Regions Spatially Correlate With High Water Vapor Heterogeneities, Minghui Diao, Mark Zondlo, Andrew Heymsfield, L. Avallone, M. Paige, Stuart Beaton, T. Campos, D. Rogers
Cloud-Scale Ice-Supersaturated Regions Spatially Correlate With High Water Vapor Heterogeneities, Minghui Diao, Mark Zondlo, Andrew Heymsfield, L. Avallone, M. Paige, Stuart Beaton, T. Campos, D. Rogers
Faculty Publications, Meteorology and Climate Science
Cirrus clouds have large yet uncertain impacts on Earth's climate. Ice supersaturation (ISS) – where the relative humidity with respect to ice (RHi) is greater than 100% – is the prerequisite condition of ice nucleation. Here we use 1 Hz (~230 m) in situ, aircraft-based observations from 87° N to 67° S to analyze the spatial characteristics of ice-supersaturated regions (ISSRs). The median length of 1-D horizontal ISSR segments is found to be very small (~1 km), which is 2 orders of magnitude smaller than previously reported. To understand the conditions of these small-scale ISSRs, we compare individual ISSRs with …
Prescribed Burning Of Logging Slash In The Boreal Forest Of Finland: Emissions And Effects On Meteorological Quantities And Soil Properties, A. Virkkula, J. Levula, T. Pohja, P. Aalto, P. Keronen, S. Schobesberger, Craig Clements, L. Pirjola, A. Kieloaho, L. Kulmala, H. Aaltonen, J. Patoskoski, J. Pumpanen, J. Rinne, T. Ruuskanen, M. Pihlatie, H. Mannien, V. Aaltonen, H. Junninen, T. Petaja, J. Backman, M. Dal Maso, T. Nieminen, T. Olsson, T. Grönholm, J. Aalto, T. Virtanen, M. Kajos, V. Kerminen, D. Shultz, J. Kukkonen, M. Sofiev, G. De Leeuw, J. Back, P. Hari, M. Kulmala
Prescribed Burning Of Logging Slash In The Boreal Forest Of Finland: Emissions And Effects On Meteorological Quantities And Soil Properties, A. Virkkula, J. Levula, T. Pohja, P. Aalto, P. Keronen, S. Schobesberger, Craig Clements, L. Pirjola, A. Kieloaho, L. Kulmala, H. Aaltonen, J. Patoskoski, J. Pumpanen, J. Rinne, T. Ruuskanen, M. Pihlatie, H. Mannien, V. Aaltonen, H. Junninen, T. Petaja, J. Backman, M. Dal Maso, T. Nieminen, T. Olsson, T. Grönholm, J. Aalto, T. Virtanen, M. Kajos, V. Kerminen, D. Shultz, J. Kukkonen, M. Sofiev, G. De Leeuw, J. Back, P. Hari, M. Kulmala
Faculty Publications, Meteorology and Climate Science
A prescribed fire experiment was conducted on 26 June 2009 in Hyytiälä, Finland, to study aerosol and trace gas emissions from prescribed fires of slash fuels and the effects of fire on soil properties in a controlled environment. A 0.8 ha forest near the SMEAR II measurement station (Station for Measuring Ecosystem-Atmosphere Relations) was cut clear; some tree trunks, all tree tops and branches were left on the ground and burned. The amount of burned organic material was ~46.8 tons (i.e., ~60 tons ha−1). The flaming phase lasted 2 h 15 min, the smoldering phase 3 h. Measurements were conducted …
Ice Crystal Formation And Evolution In Five Campaigns: Start08, Hippo Global, Dc3, Predict And Torero, Minghui Diao, Joshua Digangi, Anthony O’Brien, Mark Zondlo
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 …
Evolution Of Ice Crystal Regions On The Microscale Based On In Situ Observations, Minghui Diao, Mark Zondlo, Andrew Heymsfield, Stuart Beaton, David Rogers
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 …
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
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 …
Leeside Boundary Layer Confluence And Afternoon Thunderstorms Over Mayaguez, Puerto Rico, Mark Jury, Sen Chiao
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.).
Evaluation Of Wrf-Sfire Performance With Field Observations From The Fireflux Experiment, A. Kochanski, M. Jenkins, J. Mandel, J. Beezley, Craig Clements, S. Krueger
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 …
Kinematic Structure Of A Wildland Fire Plume Observed By Doppler Lidar, A. Charland, Craig Clements
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 …
Water Vapor And Temperature Comparisons Between Airs/Amsu-A And In Situ Aircraft Observations From 87°N To 67°S And Sensitivities To Spatial And Temporal Differences, Minghui Diao, Loayeh Jumbam, Justin Sheffield, Eric Wood, Mark Zondlo
Water Vapor And Temperature Comparisons Between Airs/Amsu-A And In Situ Aircraft Observations From 87°N To 67°S And Sensitivities To Spatial And Temporal Differences, Minghui Diao, Loayeh Jumbam, Justin Sheffield, Eric Wood, Mark Zondlo
Faculty Publications, Meteorology and Climate Science
No abstract available.
Reproduction Of Twentieth Century Intradecadal To Multidecadal Surface Temperature Variability In Radiatively Forced Coupled Climate Models, Patrick T. Brown, Eugene C. Cordero, Steven A. Mauget
Reproduction Of Twentieth Century Intradecadal To Multidecadal Surface Temperature Variability In Radiatively Forced Coupled Climate Models, Patrick T. Brown, Eugene C. Cordero, Steven A. Mauget
Faculty Publications, Meteorology and Climate Science
[1] Coupled Model Intercomparison Project 3 simulations that included time-varying radiative forcings were ranked according to their ability to consistently reproduce twentieth century intradecadal to multidecadal (IMD) surface temperature variability at the 5° by 5° spatial scale. IMD variability was identified using the running Mann-Whitney Z method. Model rankings were given context by comparing the IMD variability in preindustrial control runs to observations and by contrasting the IMD variability among the ensemble members within each model. These experiments confirmed that the inclusion of time-varying external forcings brought simulations into closer agreement with observations. Additionally, they illustrated that the magnitude of …