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Articles 1 - 30 of 66
Full-Text Articles in Meteorology
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 …
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
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
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
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
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 …
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
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 …
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 …
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, …
Environmental Controls On Pyrocumulus And Pyrocumulonimbus Initiation And Development, Neil Lareau, Craig Clements
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, …
Topography And Tropical Cyclone Structure Influence On Eyewall Evolution In Typhoon Sinlaku (2008), Cheng-Hsiang Chih, Kun-Hsuan Chou, Sen Chiao
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 …
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 …
Cold Smoke: Smoke-Induced Density Currents Cause Unexpected Smoke Transport Near Large Wildfires, Neil Lareau, Craig Clements
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 …
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
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.
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 …
Airborne Measurements Of Aerosols And Carbon Dioxide During A Prescribed Fire Experiment At A Boreal Forest Site, Aki Virkkula, Toivo Pohja, Pasi Aalto, Petri Keronen, Siegfried Schobesberger, Craig Clements, Tuukka Petäjä, Juha Nikmo, Markku Kulmala
Airborne Measurements Of Aerosols And Carbon Dioxide During A Prescribed Fire Experiment At A Boreal Forest Site, Aki Virkkula, Toivo Pohja, Pasi Aalto, Petri Keronen, Siegfried Schobesberger, Craig Clements, Tuukka Petäjä, Juha Nikmo, Markku Kulmala
Faculty Publications, Meteorology and Climate Science
During a prescribed fire experiment, CO2 and particle number concentrations, light scattering and absorption coefficients were measured from a Cessna 172 airplane. Peak number concentrations were (3 ± 1) x 106 cm–3 and they decreased faster than what can be explained by coagulation alone. The single-scattering albedo of particles grew from the values of 0.4 ± 0.1 closest to the emissions to the values of 0.8 ± 0.1 at the distance of 400 m from the emissions. The mean Ângström exponent of absorption, 1.70 ± 0.24, is in line with the published spectral absorption values of wood-smoke aerosol. The estimated …
Representation Of Ethiopian Wet Spells In Global And Nested Models, Mark Jury, Sen Chiao
Representation Of Ethiopian Wet Spells In Global And Nested Models, Mark Jury, Sen Chiao
Faculty Publications, Meteorology and Climate Science
Weather forecast and reanalysis models exhibit different performance in daily rainfall estimation over the Ethiopian highlands, 2000–2012, with ECMWF closer to observations than other models. Background is given to illustrate the Hadley circulation and easterly jets over Ethiopia, using sections on 37°E in July–August 2011. ECMWF reanalysis has a narrow band of rainfall >15 mm/day on 10°N, consistent with TRMM satellite estimates, associated with a steep gradient in meridional wind. MERRA and GFS models have a wider band of rainfall and weaker gradients in meridional winds. The contrasting background states influence a nested WRF model simulation of heavy rain in …
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 …