2011 Science Team Meeting Summary
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P4b.7 Mixed-Phase Cloud Retrievals Using Doppler Radar Spectra
P4B.7 MIXED-PHASE CLOUD RETRIEVALS USING DOPPLER RADAR SPECTRA Matthew D. Shupe* NOAA Environmental Technology Laboratory, Boulder, CO 80305 Pavlos Kollias University of Miami, Miami, FL Sergey Y. Matrosov and Timothy L. Schneider NOAA Environmental Technology Laboratory, Boulder, CO 1. INTRODUCTION 2. MEASUREMENTS The radar Doppler spectrum contains a wealth of All measurements discussed here were made by information on cloud microphysical properties. Typically, ground-based remote-sensors at the CRYSTAL-FACE radar-based cloud retrievals use only the zeroth or first eastern ground site located in Miami, Florida (25° 39' N, 80° moments of the Doppler spectrum – reflectivity and mean 26' W) on 29 July, 2002. Measurements of the radar Doppler velocity – to derive quantities such as cloud water Doppler spectrum were made by a vertically-pointing, 35- content and particle characteristic size (e.g., Liou and GHz, millimeter cloud radar (MMCR). The MMCR has 45 m Sassen 1994; Matrosov et al. 2002). When using only the vertical resolution and resolves the Doppler spectrum over moments of the Doppler spectrum, important spectral the range of -4.1 to +4.1 m s -1 to 0.064 m s -1 using 128 fast information can be lost, particularly when the spectrum is Fourier transform points. We utilize one of four alternating multi-modal. Multi-modal spectra are possible when a operational modes that samples for 1.8 seconds at 35- mixture of two or more cloud particle phases, habits, or second intervals. Radar reflectivities for the half-hour long, sizes exist in the same volume (e.g., Gossard et al. -
The Detection of Mesoscale Convective Systems by the GPM Ku-Band Spaceborne Radar
For Peer Review The Detection of Mesoscale Convective Systems by the GPM Ku-band Spaceborne Radar Journal: Journal of the Meteorological Society of Japan Manuscript ID JMSJ-2019-0034.R1 Manuscript Type: Articles Date Submitted by the n/a Author: Complete List of Authors: wang, jingyu; Pacific Northwest National Laboratory, Atmospheric Sciences & Global Change Houze, Robert ; University of Washington, Department of Atmospheric Sciences; Pacific Northwest National Laboratory, Atmospheric Sciences and Global Change Division Fan, Jiwen; Pacific Northwest National Laboratory, Atmospheric Sciences and Global Change Division Brodzik, Stacy; University of Washington, Department of Atmospheric Sciences Feng, Zhe; Pacific Northwest National Laboratory, Atmospheric Sciences and Global Change Division Hardin, Joseph; Pacific Northwest National Laboratory, Atmospheric Sciences and Global Change Division GPM evaluation, 3D reflectivity structure, Mesoscale Convective System Keywords: tracking, MCS feature, Global MCS distribution, Intense convection Page 1 of 100 For Peer Review 1 The Detection of Mesoscale Convective Systems by the 2 GPM Ku-band Spaceborne Radar 3 4 Jingyu Wang 5 Pacific Northwest National Laboratory, 6 Richland, Washington, USA 1 7 Robert. A. Houze, Jr 8 University of Washington, 9 Seattle, Washington, USA 10 Pacific Northwest National Laboratory, 11 Richland, Washington, USA 12 Jiwen Fan 13 Pacific Northwest National Laboratory, 14 Richland, Washington, USA 15 Stacy. R. Brodzik 16 University of Washington, 17 Seattle, Washington, USA 18 Zhe Feng 19 Pacific Northwest National Laboratory, 20 Richland, Washington, USA 21 and 22 Joseph C. Hardin 23 Pacific Northwest National Laboratory, 24 Richland, Washington, USA 25 26 27 March 31, 2019 28 ------------------------------------ 29 1) Corresponding author: Robert Houze, University of Washington, Seattle, Washington, 30 USA. -
Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department
Autumn 2017 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department Studying the effects of Southern African biomass burning on clouds and climate: The ORACLES mission by Professor Robert Wood, Michael Diamond, & Sarah Doherty iny aerosol particles, emitted by Fires, mainly associated with dry season Teverything from tailpipes to trees, float agricultural burning on African savannas, above us reflecting sunlight, seeding clouds and generate smoke, a chemical soup that absorbing solar heat. How exactly this happens includes a large quantity of tiny aerosol – and how it might change in the future particles. This smoke rises high in – is one of the biggest uncertainties the atmosphere driven by strong in how humans are influencing surface heating and then is climate. blown west off the coast; it In September 2016, three then subsides down toward University of Washington the cloud layer over the scientists took part in a southeastern Atlantic large NASA field campaign, Ocean. The interaction Observations of Aerosols between air moisture and Above Clouds and their smoke pollution is complex Interactions, or ORACLES, and not well understood. that is flying research planes Southern Africa produces around clouds off the west coast almost a third of the Earth’s of southern Africa to see how smoke biomass burning aerosol particles, particles and clouds interact. yet the fate of these particles and their ORACLES is a five year program, with influence on regional and global climate is three month-long aircraft field studies, and is poorly represented in climate models. led by Dr. Jens Redemann from NASA Ames The ORACLES experiment is providing Research Center in California. -
AMMA-Weather
Multi-scale Observations and Modeling of West African Tropical Rainfall Systems: AMMA-Weather Principal Investigators: Chris D. Thorncroft SUNY at Albany Chris Davis NCAR Robert A. Houze University of Washington Richard H. Johnson Colorado State University Steven A. Rutledge Colorado State University Bradley F. Smull University of Washington PROJECT OVERVIEW Executive Summary AMMA-Weather is designed to improve both fundamental understanding and weather prediction in the area of the West African monsoon through deployment of U.S. surface and upper-air observing systems in July and August 2006. These systems will be closely coordinated with International AMMA. The project will focus on the interactions between African easterly waves (AEWs) and embedded Mesoscale Convective Systems (MCSs) including the key role played by microphysics and how this is impacted by aerosol. The pronounced zonal symmetry, ubiquitous synoptic and mesoscale systems combined with the close proximity of the Saharan aerosol make the WAM an ideal natural laboratory in which to carry out these investigations. The observations will provide an important testbed for improving models used for weather and climate prediction in West Africa and the downstream breeding ground for hurricanes in the tropical Atlantic. The international AMMA program consists of scientists from more than 20 countries in Africa, Europe, and the US. Owing to the efforts of European countries, a strong infrastructure is being installed providing a unique opportunity for US participation. Support in excess of twenty million Euros has already been secured by Europeans for AMMA including the 2006 field campaign. Significantly for AMMA-Weather, this will include support for the U.S. -
Leading and Trailing Anvil Clouds of West African Squall Lines
1114 JOURNAL OF THE ATMOSPHERIC SCIENCES VOLUME 68 Leading and Trailing Anvil Clouds of West African Squall Lines JASMINE CETRONE AND ROBERT A. HOUZE JR. Department of Atmospheric Sciences, University of Washington, Seattle, Washington (Manuscript received 10 June 2010, in final form 5 January 2011) ABSTRACT The anvil clouds of tropical squall-line systems over West Africa have been examined using cloud radar data and divided into those that appear ahead of the leading convective line and those on the trailing side of the system. The leading anvils are generally higher in altitude than the trailing anvil, likely because the hydrometeors in the leading anvil are directly connected to the convective updraft, while the trailing anvil generally extends out of the lower-topped stratiform precipitation region. When the anvils are subdivided into thick, medium, and thin portions, the thick leading anvil is seen to have systematically higher reflectivity than the thick trailing anvil, suggesting that the leading anvil contains numerous larger ice particles owing to its direct connection to the convective region. As the leading anvil ages and thins, it retains its top. The leading anvil appears to add hydrometeors at the highest altitudes, while the trailing anvil is able to moisten a deep layer of the atmosphere. 1. Introduction layer ascent (Zipser 1969, 1977; Houze 1977; Houze et al. 1989). We take advantage of a set of data collected at Satellite data show that a large portion of upper-level- Niamey, Niger, as part of the African Monsoon Multi- cloud ice clouds in the tropics originate as anvil clouds disciplinary Analyses (AMMA) field program of summer associated with precipitating deep convection (Luo and 2006 (see Redelsperger et al. -
The Olympic Mountains Experiment (Olympex)
THE OLYMPIC MOUNTAINS EXPERIMENT (OLYMPEX) ROBERT A. HOUZE JR., LYNN A. MCMURDIE, WALTER A. PETERSEN, MATHEW R. SCHWAllER, WIllIAM BACCUS, JESSICA D. LUNDQUIST, CLIFFORD F. MASS, BART NIJSSEN, STEVEN A. RUTLEDGE, DAVID R. HUDAK, SIMONE TANEllI, GERALD G. MACE, MICHAEL R. POEllOT, DENNIS P. LETTENMAIER, JOSEph P. ZAGRODNIK, ANGELA K. ROWE, JENNIFER C. DEHART, LUKE E. MADAUS, AND HANNAH C. BARNES OLYMPEX is a comprehensive field campaign to study how precipitation in Pacific storms is modified by passage over coastal mountains. hen frontal systems pass over midlatitude the lee sides. Snow deposited at high elevations by mountain ranges, precipitation is modified, these storms is an important form of water storage Woften with substantial enhancement on the around the globe. However, precipitation over and windward slopes and reduced accumulations on near Earth’s mountain ranges has long been very difficult to measure. As a result, the physical and dynamical mechanisms of enhancement and reduc- AFFILIATIONS: HOUZE, MCMURDIE, LUNDQUIST, MASS, NIJSSEN, tion of precipitation accompanying storm passage ZAGRODNIK, ROWE, AND DEHART—University of Washington, over mountains remain only partially understood. Seattle, Washington; PETERSON—NASA Marshall Space Flight Center, Huntsville, Alabama; SCHWAllER—NASA Goddard Space The launch of the Global Precipitation Measurement Flight Center, Greenbelt, Maryland; HOUZE AND BARNES—Pa- (GPM) satellite in February 2014 by the U.S. National cific Northwest National Laboratory, Richland, Washington; Aeronautics and Space Administration (NASA) and BACCUS—Olympic National Park, Port Angeles, Washington; the Japan Aerospace Exploration Agency (Hou et al. RUTLEDGE—Colorado State University, Fort Collins, Colorado; 2014) fosters exploration of precipitation processes HUDAK—Environment and Climate Change Canada, King City, over most of Earth’s mountain ranges. -
Use of Cloud Radar Observations for Model Evaluation: a Probabilistic Approach Christian Jakob Bureau of Meteorology Research Centre, Melbourne, Australia
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, D03202, doi:10.1029/2003JD003473, 2004 Use of cloud radar observations for model evaluation: A probabilistic approach Christian Jakob Bureau of Meteorology Research Centre, Melbourne, Australia Robert Pincus and Ce´cile Hannay Climate Diagnostics Center, National Oceanic and Atmospheric Administration Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado, USA Kuan-Man Xu NASA Langley Research Center, Hampton, Virginia, USA Received 30 January 2003; revised 21 October 2003; accepted 17 November 2003; published 5 February 2004. [1] The use of narrow-beam, ground-based active remote sensors (such as cloud radars and lidars) for long-term observations provides valuable new measurements of the vertical structure of cloud fields. These observations might be quite valuable as tests for numerical simulations, but the vastly different spatial and temporal scales of the observations and simulation must first be reconciled. Typically, the observations are averaged over time and those averages are claimed to be representative of a given model spatial scale, though the equivalence of temporal and spatial averages is known to be quite tenuous. This paper explores an alternative method of model evaluation based on the interpretation of model cloud predictions as probabilistic forecasts at the observation point. This approach requires no assumptions about statistical stationarity and allows the use of an existing, well- developed suite of analytic tools. Time-averaging and probabilistic evaluation techniques are contrasted, and their performance is explored using a set of ‘‘perfect’’ forecasts and observations extracted from a long cloud system model simulation of continental convection. This idealized example demonstrates that simple time averaging always obscures forecast skill regardless of model domain size. -
Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department
Autumn 2012 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department The Weather Challenge by Lynn McMurdie he UW Atmospheric Sciences spring Tforecast contest has been an annual tradition in the department for many years. It’s a time when faculty and students alike agonize over whether there will be a marine push or a convergence zone wrecking their forecast for maximum temperature and precipitation probability at SeaTac. The winner earns department-wide recognition with their name engraved on a trophy, and the respect (or envy!) of their fellow forecasters. Now imagine forecasting for a wide-variety of cities across the United States and competing against thousands of other contestants from many other universities and institutions across the country. That’s just what a group of intrepid undergraduate and graduate students did this past year. For the first time, University of Washington entered a team in the national WxChallenge. The WxChallenge contest was developed A few of this year’s participants. From left: Xiaojuan Liu, Jack Neukirchen, Hannah Barnes, by the University of Oklahoma and officially started in 2006 when it replaced the National Jen DeHart, Elizabeth Maroon, Lynn McMurdie, Magdalena Szabo and Ken Dixon. Collegiate Weather Forecast contest. The goal of challenges. Often impromptu discussions would slipped into 3rd place. Aaron Hill, a recent 2012 the WxChallenge is to make the best forecast of erupt in the computer lab or someone’s office grad, had the top score in the nation for wind the next day’s maximum temperature, minimum when tricky forecasts were looming overhead at Riverton, WY. -
Cloud Classification and Distribution of Cloud Types in Beijing Using Ka
ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 36, AUGUST 2019, 793–803 • Original Paper • Cloud Classification and Distribution of Cloud Types in Beijing Using Ka-Band Radar Data Juan HUO∗, Yongheng BI, Daren LU,¨ and Shu DUAN Key Laboratory for Atmosphere and Global Environment Observation, Chinese Academy of Sciences, Beijing, China 100029 (Received 27 December 2018; revised 15 April 2019; accepted 23 April 2019) ABSTRACT A cloud clustering and classification algorithm is developed for a ground-based Ka-band radar system in the vertically pointing mode. Cloud profiles are grouped based on the combination of a time–height clustering method and the k-means clustering method. The cloud classification algorithm, developed using a fuzzy logic method, uses nine physical parameters to classify clouds into nine types: cirrostratus, cirrocumulus, altocumulus, altostratus, stratus, stratocumulus, nimbostratus, cumulus or cumulonimbus. The performance of the clustering and classification algorithm is presented by comparison with all-sky images taken from January to June 2014. Overall, 92% of the cloud profiles are clustered successfully and the agree- ment in classification between the radar system and the all-sky imager is 87%. The distribution of cloud types in Beijing from January 2014 to December 2017 is studied based on the clustering and classification algorithm. The statistics show that cirrostratus clouds have the highest occurrence frequency (24%) among the nine cloud types. High-level clouds have the maximum occurrence frequency and low-level clouds the minimum occurrence frequency. Key words: clouds, clustering algorithm, classification algorithm, radar, cloud type Citation: Huo, J., Y. H. Bi, D. R. Lu,¨ and S. Duan, 2019: Cloud classification and distribution of cloud types in Beijing using Ka-band radar data. -
The Tropical Warm Pool International Cloud Experiment
THE TROPICAL WARM POOL INTERNATIONAL CLOUD EXPERIMENT BY PETER T. MAY, JAMES H. MATHER, GERAINT VAUGHAN, CHRISTIAN JAKOB, GREG M. MCFARQUHAR, KEITH N. BOWER, AND GERALD G. MACE A comprehensive observing campaign in Darwin, including a ship, five aircraft, and frequent soundings, is furthering weather and climate change studies through improved understanding and modeling of cloud and aerosol processes in tropical cloud systems. crucial factor in our ability to forecast future of this region and through it the global stratosphere climate change is a better representation (e.g., Russell et al. 1993; Folkins 2002). Understanding A of tropical cloud systems, and their heating and the transport of gases and particles in deep convec- radiative impacts in climate models (Stephens 2005; tion is also therefore of global importance. Del Genio and Kovari 2002; Neale and Slingo 2003; As a response to this challenge, a major field Spencer and Slingo 2003). This requires a better experiment named the Tropical Warm Pool Interna- understanding of the factors that control tropical tional Cloud Experiment (TWP-ICE), including the convection as well as an improved understanding of U.K. Aerosol and Chemical Transport in Tropical how the characteristics of the convection affect the Convection (ACTIVE) consortium, was undertaken nature of the cloud particles that are found in deep in the Darwin, Northern Australia, area in January convective anvils and tropical cirrus. Deep convec- and February 2006. The experiment was designed tion also lifts boundary layer air into the tropical to provide a comprehensive dataset for the develop- tropopause layer (TTL), affecting the composition ment of cloud remote-sensing retrievals and initial- AFFILIATIONS: MAY—Centre for Australian Weather and CORRESPONDING AUTHOR: Peter T. -
Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department
Autumn 2016 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department OLYMPEX: Testing a NASA Satellite on the Olympic Peninsula by Dr. Lynn McMurdie and Professor Robert A. Houze, Jr. It’s early October 2015, and NASA is project to test a new precipitation measuring satellite, and scientists from the Departments of Atmospheric Sciences and Civil and Environmental Engineering are leading this massive adventure. There is no need for earplugs to protect your ears from the roar of rockets or a countdown: the Olympic Mountains Experiment (OLYMPEX) is being launched by a mule train. mountains and nearby ocean. Highly specialized radars were set up at several locations on both sides of the mountains. For over three years, Houze and Center, McMurdie worked with NASA were planned and colleagues, wrote plans, explored directed. Often 2-3 air craft were in the air at instruments in remote areas, radars on the coast and inland, and locations for aircraft patterns. McMurdie directed a staging. Two aircraft stationed at McChord team of graduate student forecasters, who Mules carry OLYMPEX instruments through wilderness to the high terrain of the Olympic Mts. were crucial for deciding the exact times to the storms with cloud instruments to measure launch the aircraft, operate radars and launch OLYMPEX occurred last fall and winter and the sizes and types of rain and snow particles. soundings. The lead graduate student forecaster was led by Prof. Houze and Dr. McMurdie of To realize this plan, McMurdie and Houze was Jennifer DeHart of the Department of the Department of Atmospheric Sciences. -
Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department
Autumn 2011 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department Making of the YouTube Can Crushing Video by Kelly McCusker he Department of Atmospheric Sciences and boiled down to the essential information, all brief departure to smooth jazz while the Safety TOutreach group has recently ventured while remaining within the story arc and incor- Chicken shared his safety message. into a bold new frontier: YouTube. Composed porating some humor. “Due to recent advances The rest of the crew for this video included: of faculty, staff, and students, our group has in de-cylindrification theory, the power to crush Bryce Harrop, Brian Smoliak, Jack Scheff, and been volunteering time for over 20 years, shar- cans without undue physical exertion is now in yours truly, with new additions for upcoming ing science with youth on visits to the depart- the power of everyday citizens like yourself!” videos. The process was exceptionally fun, but ment, demonstrating concepts relevant to the Pure genius! We had lots of fun coming up with we did run across some pitfalls, many of which atmosphere, and generally illustrating the won- everyone’s lines. Can you pick out the lines that the group has since corrected. In order to cre- ders of our field. ate high definition video, we now utilize an reference an early 90’s song? In early 2009, the outreach group was HD video camera from the UW Student Tech Step three: filming. We used the department approached by UW’s Joint Institute for the Fee equipment office. We also now focus on Study of the Atmosphere and Ocean (JISAO) to video camera, providing us the flexibility to maintaining consistent audio throughout (care- participate in their Science in 180 initiative.