The most recent meeting of the Central Illinois Chapter was held 15 May 2002 at The Depot restaurant in Lincoln, Illinois. After dinner, a brief business meeting was conducted. President Holicky polled group opinion on hosting a regional AMS conference. There was interest and a decision whether or not to pursue hosting the conference is expected to be reached at the next meeting. The evening's speaker was Brad Ketcham, forecaster at the Central Illinois National Weather Service Forecast Office. His topic was "The Interactive Forecast Preparation System (IFPS): A Digital Forecasting Process." IFPS is a new component of the Advanced Weather Interactive Processing System (AWIPS). It allows the forecaster to view and edit gridded fields of weather information. It also allows the forecaster to blend and manually modify model forecasts. Users may generate these fields with any combination of model forecasts, other guidance products, observations, or premade user-generated gridded forecasts. IFPS gives users the ability to generate products from the digital database into various formats such as tabular, text, graphical imagery and gridded files. With IFPS, the forecaster can present the forecast products in number of ways to suit customer requirements and desires. Initial nationwide implementation of IFPS is underway but development will continue for some time. It promises to be an exciting addition to the NWS forecast process that will take the weather agency into the 21st century.---Scott Kampas.
CENTRAL NORTH CAROLINA
The speaker for the March 21, 2002 meeting was Dr. Jim Clark from Duke University. Jim heads the initiative for ecological forecasting for the Ecological Society of America and spoke on the issue of ecological forecasting.
Scientists try and forecast ecological change to anticipate the variability of ecosystem goods and services, hopefully being able to identify the impacts of events such as the Dust Bowl of the 1930s. Other goals of ecological forecasting are to anticipate ecosystem variability and develop policy scenarios.
The basic science of ecological forecasting is based on large-scale experiments. Large-scale experiments are performed to examine processes on the relevant scale, which is difficult to do in a lab. Examples of these experiments are fumigation of CO2 at Duke Forest, experimental tree blowdowns in Coweeta, NC, and experimental burns in Bor Island, Siberia.
Making accurate forecasts depends on understanding the uncertainties in the system and making efficient computations. Applying the forecast depends on what types of forecasts are needed and by whom. Understand how the forecast will be used and how to communicate it are also crucial.
Obstacles to credible forecasts of ecological parameters are uncertainties in ecological data, the relationships between parameters, and assumptions made in models. All of these uncertainties then propagate to forecasts.
In order to make forecasts effective, decision makers must be engaged at the start of the process and forecasts must be targeted to societal demands. Future steps to take are the organization of workshops through the Ecological Society of America, using new empirical data to improve modeling, and taking advantage of technological advances in statistics and computing power.
The talk ended at 8:45 p.m., and after a brief question and answer session, the meeting ended at 8:53 p.m.
The final meeting of the 2001-2002 chapter year was held on Thursday, April 18, 2002. The speaker for the evening was Dr. Larry Carey Assistant Professor of Meteorology in the Department of Marine, Earth and Atmospheric Science at NC State. His talk for the evening was titled, "The Relationship between Severe Thunderstorms and Polarity of Cloud-to-Ground Lightning."
Larry began his talk by giving an overview of the typical behavior of cloud-to-ground (CTG) lightning in "ordinary" (non-severe) thunderstorms, and then followed that with some case study data of CTG lightning in severe thunderstorms along with a climatology of severe thunderstorms.
The idealized electrical structure of an ordinary thunderstorm features a large area of positive charge in the upper region and anvil of the storm, where temperatures are less than -20°C. Below that, there is an area of layered negative charge where temperatures are between -20°C and -10°C. Finally, near the base of the storm is a smaller region of positive charge.
One theory of how this charge distribution develops is a convective mechanism where the air motions separate and carry charge. Currently, most scientists favor a precipitation-based mechanism. One such mechanism, the non-inductive charge (NIC) theory, where rebounding collisions between large and small ice crystals in the presence of supercooled water result in positively charged ice crystals in the anvil and negatively charged graupel at mid-levels.
Several case studies showing lightning charge distribution around severe thunderstorms were presented, including the Plainfield, IL supercell that produced an F5 tornado in August 1990. A study by Seimon (1993) showed that just prior to tornadogenesis, 80-100% of the CTG lightning carried a positive charge, while after the tornado occurred, negative lightning became more predominate.
During the Spencer, SD F4 tornado in May 1998, the peak positive flash rate (18 CTG strikes per minute) occurred while the F4 tornado damage was taking place. This is in contrast to other "anomalous" storms, where the change from predominately positive CTG strikes to negative occurs prior to tornadogenesis, such as the Plainfield storm.
Larry next presented a climatology of significant severe weather events trying to correlate their presence with the presence or absence of positive CTG lightning. First, he noted that the density of sensors in the National Lightning Detection Network (NLDN) is higher in the Southeast than other regions of the U.S. When looking at the lightning data in this region, a high number of low peak current positive CTG flashes are seen. He speculates that these are likely misidentified intra-cloud flashes and should be removed from the analysis.
Statistics were computed on over 68,000 events. One significant result is that 80-90% of the severe reports were associated with storms where the percentage of positive CTG lightning is less than 50%. Storms were categorized as predominately negative (>90% negative CTG lightning), predominately positive (>50% positive CTG lightning), and high frequency, predominately positive (>50% positive CTG lightning and >0.01 km-2 hr-1 flash density).
Results of this classification showed that in the eastern U.S. most severe storms have "typical" CTG lightning behavior, which is primarily negative. In the southern plains, 30-40% of the severe storms are accompanied by predominately positive CTG lightning, while in the northern plains, more than 50% of the severe storms were accompanied by primarily positive CTG lightning.
Thus, it was concluded that in the northern plains positive CTG lightning was common in severe thunderstorms. In the southern plains, it does occur, but is more rare, while it is extremely rare in the eastern states. Also, it was noted that the amount of positive CTG flashes were not related to the intensity of severe weather, such as hail size or the F-scale rating of a tornado.
Larry's talk ended at 8:55 p.m., and after a few questions, the meeting ended at 9 p.m.---/S/Michael J. Brennan.
The Delaware and Philadelphia Area Chapter celebrated the end of its first full year in existence at its May 2002 meeting with a talk by Dr. Anthony Broccoli of NOAA/GFDL entitled 'What Every Meteorologist Should Know About Global Warming'. Dr. Broccoli's talk was primarily focused on the ability of the current generation of GCMs to accurately represent past, present, and future climate patterns. The debate on greenhouse warming can be broken down into three critical questions: detection, attribution, and policy. Dr. Broccoli's personal prediction is that debate over detection will soon end and that future controversy will center on how much of the warming trends can be attributed to humans, and more significantly, on policy questions of how we should respond.
Following a review of current greenhouse gas emissions and global temperature trends, Dr. Broccoli addressed some questions meteorologists are frequently asked by the public. The warm winter of 2001-2002 can not be directly linked to global warming, but how many similar winters would be needed to do so? It is obviously something we will only be able to look back at in retrospect. The lack of significant snowfall in the region last winter also has raised some concern about future impacts. However, the variability of annual snowfall is so high that it would take decades of change to get out of the current range of variability. Finally, Dr. Broccoli discussed a series of current GFDL model runs. A number of model runs with different initial conditions show different interannual variability, but agree as to overall trends in global temperature and match historical temperature trends very closely. This agreement leads Dr. Broccoli to conclude that though the atmosphere is a chaotic system, climate may have enough constraints to be predictable. He is optimistic that the models will continue to improve and will provide useful information to decision makers.
A lengthy question and answer session followed, covering a wide range of subjects from past warm periods, to urban heat islands, to the impact of alternative energy sources such as fuel cells. In Dr. Broccoli's opinion, future efforts in improving modeling will focus on better spatial resolution as computer power continues to increase, and on better defining cloud feedbacks.---Keith G. Henderson.
DISTRICT OF COLUMBIA
The 16 April 2002 meeting was held at 30 January at the NOAA Auditorium and Science Center in Silver Spring, Maryland. During the short business meeting the following topics were covered:
(1) The chapter is looking for volunteers to run for chapter office. (2) The Chapter, the Weather Channel, and the National AMS are co-sponsoring the Mid-Atlantic Winter Storms Conference, 3-5 October 2002. The Chapter is looking for volunteers to help the conference. (3) The June Science Fair meeting date is still in the works as the chapter hasn't yet settled on a speaker.
The speakers were Barbara McNaught Watson, Warning Coordination Meteorologist at the National Weather Service's (NWS) Baltimore-Washington Forecast Office; and Henry Black, Assistant Director for Communications at the Maryland Emergency Management Agency (MEMA) State Emergency Operations Center. Their topic for the evening was "What You Don't Know About Severe Weather Can Kill You!"
Barbara Watson gave a detailed account of the September 24, 2002, College Park MD tornadoes. She said that there were 5 tracks in this multi-vortex storm that caused more than $100 million dollars damage. The tornado was evaluated to be an F3 when it touched down in College Park. It occurred in the warm sector in advance of a cold front. There was lots of sheer with strong tilting and rotation in this "low top" Supercell with cloud tops at 25-45K feet. This was a rare event -- the last such storm occurred about 75 years ago. The NWS issued numerous watches, warnings and Special Weather statements throughout the day; the tornado warning for the College Park area (including Prince Georges, Anne Arundel and Montgomery Counties) was issued at 5:10 PM. The event brought to light the facts that (1) not all Maryland schools have tornado/sever weather plans; and (2) the Maryland schools that have tornado plans neglected to include after school programs in their plans. These plans are mandatory in Virginia. Lastly, Watson stated that the NWS did not issue a warning for Baltimore -- this was a tough decision, but the Terminal Doppler Weather Radar at the Baltimore-Washington International Airport (TDWR-BWI) showed that the storm was weakening.
The second speaker for the evening, Henry (Hank) Black of MEMA stated that the State Emergency Operations Center is charge with protecting the lives and property of Maryland's citizens from all hazards. MEMA's mission is mitigation, preparedness, response and recovery. Information on MEMA is available at www.mema.state.md.org---Lauraileen O'Connor.
The May meeting of the AMS Jackson chapter was held Monday, May 20th at 7 pm, at the National Weather Service (NWS) office in Jackson, MS. The topic of the meeting was the new Weather Event Simulator being used by the National Weather Service for hazardous weather training. This presentation was an opportunity for those in attendance to learn more about the current and future status of meteorological training for severe weather, radar meteorology, and the meteorology of other hazardous weather phenomena.
The meeting was opened by President Alan Gerard, and Dave Biggar followed with the treasurer’s report. The next chapter meeting was proposed for late June, and potential topics and speakers were suggested for future meetings. Officer elections were discussed for the 2002-03 chapter year, but an official election did not take place. Nominations were made for the 2002 Susan Oakley award for public service. It was decided that this year’s award should be presented to Bill Weisenberger, Madison County Emergency Management Association Director. Through Mr Weisenberger’s hard work and devotion, recovery has been easier for Madison County residents struck by a devastating F4 tornado last November.
Following the chapter business session, Mr. Gerard began his presentation on the NWS Warning Event Simulator (WES), a training tool being implemented at NWS offices around the country. This simulator follows in the spirit of other training simulators, such as the flight simulator used to train pilots for unexpected emergencies. Through advanced data archiving, the WES recreates a severe weather event, and allows meteorologists to experience the event in a real-time environment. The simulation is run on a linux box running Advanced Interactive Processing System (AWIPS) software. During the simulation, meteorologists are responsible for analyzing the same weather data that was available during the actual event, including all observational, radar, and model data. Based on the data, the meteorologist is responsible for making warning decisions, and issuing warning products.
In his demonstration of the WES, Gerard ran through a simulation of the April 8th, 1998 severe weather outbreak, centered over northern and central Alabama. This case is being used at all NWS simulator sites. During the simulation, Gerard explained weather and radar analysis techniques used by NWS meteorologists in the warning decision making process. He pointed out certain mesoscale features in surface and satellite imagery, that offered important clues to the near storm environment and the expected storm type.
In an effort to increase relations with the media, NWS Jackson, MS has proposed that area broadcast meteorologists experience the WES. The NWS Jackson believes this learning experience would increase their communication with the media during times of severe weather.
Gerard concluded his presentation with a question and answer session. Questions concerning the November 24th tornado outbreak were raised, and Gerard displayed archive data from this event, focusing on the F4 tornado that struck Madison County.
The meeting was adjourned by Alan Gerard.---Eric Carpenter.
LYNDON STATE COLLEGE
Start: 7:00 pm
President Cegeon Chan
Vice President Gabriel Langbauer
Secretary Amy Lawton
Public Relations Heather Vieira
End: 7:15 pm---Amy Lawton.
NORTH TEXAS CHAPTER OF THE AMERICAN METEOROLOGICAL SOCIETY NEWSLETTER FOR MAY 17, 2002
Hello Fellow Weather Enthusiasts,
I apologize for getting this edition of the AMS newsletter out so late, and so soon to our next meeting which will be this coming Tuesday evening. I just returned from a trip to Beaumont Texas to attend the Jefferson County Hurricane Conference (yes it is that time of year for those of us at the West Gulf RFC to start planning for the hurricane season ). The conferences' main speaker was Dr. Steve Lyons, former SSD employee at Southern Region Headquarters who is now the tropical weather expert at The Weather Channel. It was a very informative meeting.
As I mentioned, our next meeting (and final formal meeting until September) will be this Tuesday, May 21, 2002, at 7 PM. The meeting will be at our usual meeting place at the National Weather Service WFO/RFC complex in north Fort Worth. Our primary guest speaker for the evening will be Keith Wells, Assistant Emergency Management Coordinator of the Tarrant County Emergency Management Office. The title of Keith's talk will be "Emergency Management Perspective of the Fort Worth Tornadoes." Keith Wells is a native of Fort Worth. He attended the University of Texas at El Paso and worked as a technician for Southwestern Bell Telephone Company in Fort Worth prior to earning a Bachelor of Science in Emergency Administration and Planning from the University of North Texas in 1991.
Keith began his career in emergency management as a Planning Officer for the Texas Division of Emergency Management at the Pantex Nuclear Weapons Plant near Amarillo, where he was responsible for coordinating plant emergency management plans with local and state plans. His next position was with the Mason & Hanger Corporation at the Pantex Plant, where he performed a variety of emergency management duties including liaison with local, state, and federal agencies; plant evacuation and shelter planning; facility operational readiness reviews; and conducting emergency exercises.
In March of 1999 Keith returned to Fort Worth as Assistant Emergency Management Coordinator in the Fort Worth - Tarrant County Emergency Management Office. His day-to-day duties include responsibility for managing the City/County Emergency Operations Center, writing emergency plans and procedures, public education programs, and responding to media inquiries. Keith was responsible for coordinating public safety planning for Y2K. He responded to the Wedgwood Baptist Church shootings, the March 28th, 2000 Fort Worth tornado, and a variety of smaller incidents such as flash floods, multi-alarm fires, and hazardous materials spills.
He is President of the University of North Texas Emergency Administration and Planning Alumni Association and serves on the University of North Texas Emergency and Planning Program Advisory Committee.
Keith is married and has two children.
As a part of Keith's presentation, we will also have a second speaker, Mike Heskett, the National Weather Service RACES coordinator. Mike will give a short presentation explaining the relationship between the Tarrant County Emergency Management Office and the Radio Amateur Civil Emergency Service as it relates to the communication of tornado and severe storm information to the NWS. It promises to be a very informative evening...I hope all of you will plan on attending.
The last order of business for the final meeting of the year is the election of officers. I was informed by our current president, Mike Vescio, that he will be unable to continue on as president next year. I want to thank Mike for his willingness to take over as chapter president when we needed someone to take the position last fall. Mike, you did a great job! Nominations for officers are still open, especially for the position of President. The only qualifications for president are that you be a member of the national American Meteorological Society, and that you be a dues-paying member of our local chapter. Since I have been out of town all week I do not know as of this moment who has been nominated for the four elected positions. I have informed President Vescio that I am willing to remain chapter secretary if elected. So please get your nominations to either me or President Vescio before the meeting Tuesday (yes, you CAN nominate yourself)!
Hope to see all of you Tuesday!---Greg Story.
April 2002 Meeting Minutes
The Omaha-Offutt chapter of the AMS held their monthly meeting 18 April 2002 at the officers club, Offutt Air Force Base. 24 members and guests were present. The evening began at 6:30p.m with a social half hour in the Raiders Lounge. The members proceeded to the dinning hall for dinner and eventually into a reserved side room for the business meeting.
President Gene Wall called the meeting to order and turned the floor over to the secretary and treasurer for their reports. Jeremy Wesely read the March minutes and Dr. John Zapotocny reported on the state of the treasury. Dr. Zapotocny also corrected a mistake in the records changing our official membership from 52 to 51. In forecast contest news, Carolyn Petri took first prize while Jeremy Wesely came in second. Phillip Johnson thanked all members that helped judge at local science fairs and requested suggestions for prizes to award next year.
Dr. Dewey announced that the University of Nebraska's student AMS chapter is selling severe weather calendars as a fundraiser at $10 a piece. Gene reminded members that May is election of new officers month and members should think about running. We also need to form a nomination committee to run the election. In addition, May is member's night and any one interested in speaking or presenting should talk with one of the chapter officers. Dr. Dewey introduced our guest speaker, Dr. Sashi Verma of the University of Nebraska.
Dr. Sashi Verma has earned degrees in engineering from the University of Colorado and the University of Colorado State. Dr. Verma's presentation was titled "Carbon Sequestration and Global Warming." Measurements of atmospheric CO2 concentrations have revealed significant increases in atmospheric CO2 over the last century leading researches to research carbon sequestration possibilities. In order to accurately predict climate change a knowledge of the ecosystem, carbon sources, and sinks is needed. Carbon mitigation lessens the carbon input into the atmosphere and increases the amount of stored (sequestered) carbon. Carbon sequestration within the soil improves the soil's organic matter. Dr. Verma's goals are to investigate carbon sequestration potential in irrigated farming ground and to know why one ecosystem sequesters more or less than another. In addition, Dr. Verma is attempting to develop cost effective methods of sequestering carbon.
May 2002 Meeting Minutes
The Omaha-Offutt chapter of the AMS held their final meeting of the season at 11:30a.m 16 May 2002 at China Road in Bellevue. The next meeting will be led by newly elected officers in September 2002. Twenty members and guests were present. Members ordered off of the menu and the business portion of the meeting was conducted while the food was prepared. Following lunch, Omaha-Offutt chapter member and speaker Bruce Telfeyan gave a very informative presentation on the Air Force's Interactive Gridded Analysis Display System (IGrADS).
President Gene Wall called the meeting to order and asked new members and guests to introduce themselves. Lt. Kevin Lacroix, Ms. Cara Combs, Lt. Col. Beth McNulty, and Mr. Dan Smith introduced themselves and spoke briefly on their backgrounds. Col. James Hoke also introduced himself and gave his farewells to the chapter, as he will be leaving the local area. Following introductions, Dr. John Zapotocny reported the treasury's balance of $964.34 and announced forecast contest winners. Scott Risch took first place on last month's contest with the first perfect score in several years. Scott perfectly forecasted the month's warmest and coldest temperatures along with the number of thunderstorm days. Paul Demmert and John Schmit took first and second place overall when all forecast contest scores from this past year were added and averaged. In other old business, Jeremy Wesely read the April minutes that Bruce Telfeyan motioned to approve and Kirth Pederson seconded.
Gene asked for volunteers to audit the treasurer's books preparing the way for the transfer of officers. Gene then announced the members of this year's nominations committee, which were Bruce Telfeyan, Lou Riva, and Ed Bensman. The head of the committee, Bruce Telfeyan, handed out the ballots and counted the votes. Gene and Jeremy were both re-elected and the chapter officers for the next year are as follows:
President: Gene Wall
Vice President: Scott Risch
Corresponding Secretary: Cara Combs
Recording Secretary: Jeremy Wesely
Treasurer: Matt Sittel
Gene thanked all previous officers for their hard work in the past year. Chapter officers will meet this summer to plan out our proposed activities for next year. The first meeting will most likely be in mid to late September. Stay tuned for details. Guest Speaker Bruce Telfeyan of the Air Force Weather Agency's (AFWA) technology exploitation branch spoke on the Air Force's Interactive Gridded Analysis Display System (IGrADS). IGrADS can be found on the AFWA web page, which is known as the Joint Air Force and Army Weather Information Network (JAAWIN). IGrADS is used to display meteograms, skew-Ts, vertical cross-sections, forecast maps, forecast vertical profiles, and alphanumeric model output. IGrADS provides the user with the freedom to choose how a product will be visualized. For example, the user can define the parameters to be contoured and the interval at which they are contoured.---Jeremy Wesely.
The USGS Stream Gauging Program in Colorado
Mr. Keith Lucey, Pueblo Sub-District Chief, USGS
May 31, 2002
The Pikes Peak Chapter of the American Meteorological Society began 2002 with a dinner and presentation at the historic Stagecoach Inn in Manitou Springs, Colorado. The guest speaker of the evening was Mr. Keith Lucey, Pueblo Sub-District Chief of the US Geological Survey (USGS). Mr. Lucey traveled from Pueblo Colorado to talk to our members about the USGS stream gauging network, in particular the local gauges, and how the gauges are operated and maintained.
The USGS has about 10,000 employees in 4 divisions: geology, biology, mapping and water resources. About a half of all USGS employees work in water resources. The state of Colorado has about 150 employees of which 30 work in the Pueblo office. The office has two sections; the studies and data sections. The data section employs about 20 people. The Pueblo office area of responsibility covers the Rio Grande and Arkansas basins.
The Colorado database consists of records of 1152 sites, of which 600 are active. Of the 600 active gauges, 260 are operated by the USGS. Funding to operate and maintain stream gauges is provided by several Federal, State, and local agencies with mutual interests. Federal matching funds are provided for stream gauges cooperatively funded by State and local agencies. On average, each cooperative gauge is funded 47% from Federal matching funds and 53% from local funds. There are 26 stream monitoring gauges in and around Colorado Springs. Colorado also has one Benchmark station. A benchmark station monitors a basin that has had little human intervention, past or planned, that might affect the stream flow. Colorado’s benchmark station is near Leadville, Colorado. Every year, water resources for eastern and western Colorado are documented in two volumes for official publication. The water year runs from 1 October to 30 September. Each volume, about one inch thick, costs around $19.00 and is the official water resource record for the area. Reports are from the Colorado District Home Page: http://co.water.usgs.gov/Pubs/index.html#DataReport or can be purchased from 1-888-ASK-USGS.
Most gauging stations in the Colorado Springs area measure stream stage with a bubbler. A bubbler works by passing compressed gas (air or nitrogen) threw an orifice tube placed on the stream bed. The pressure required to expel the gasses (bubble) is equal to the water pressure and hence proportional to the water depth above the orifice tube. The stream bed cross-sectional area is determined by field surveys. Velocity and cross-sectional area is used to determine stream flow. A baseline of differing stage readings and flow rates is needed to accurately characterize a flow rate, hence new gauges require several significant events. Heavy rains, moderate rainfall and low or drought conditions are all needed to chart the staging data versus flow rate before accurate flow rates can be determined from gauge readings alone.
Each station sends its readings back to the USGS via data bursts over the GOES Data Collection System (GDCS) every four hours. Stream data is read every 15 minutes at the gauge and stored for transmission. If the stream stage increases one half foot in 15 minutes, then the alarm mode is triggered and the data are transmitted to the GCDS at more frequent intervals. These intervals are called Random Transmissions and are useful for monitoring changing hydrologic conditions.
In addition to stream data, some gauges have precipitation recorders as well. Colorado has 65 USGS precipitation gauges providing a 7-month annual rainfall record. The gauges are not used in winter since they are not heated and would not provide a beneficial report of moisture equivalent in snowfall events. Rainfall is measured every 5 minutes and Random Transmissions occur when rainfall increases 0.2 inches in any 5-minute period.
Handouts describing all the resources available from the Pueblo Sub-District (online and in hard copy) were distributed to attendees.
The meeting convened with a call for volunteers to attend an executive meeting the following week to lay out the events for the new year. A good time was had by all and many new friendships, both professional and personal were established.---Jon Cornick.
********** JUNE 2002 MEETING ANNOUNCEMENT **********
Date: Thursday, June 20, 2002
Place: Carrow's of Carpinteria, 4405 Via Real
Time: Dinner - 630 PM; Meeting - 730 PM
Round Table Discussion
Presentation of Science Fair Winners
Election of Officers for 2002-2003
Award for Precipitation Contest '01-02
This is the final meeting of the year for the Santa Barbara/Ventura Chapter of AMS. A round table discussion will allow each of our members and guests to discuss topics of mutual interest or to introduce projects on which they are currently engaged. The floor is open to any ideas within the general field of meteorology.
County science fair winners from Santa Barbara and Ventura will be invited to make presentations at this meeting. These presentations have been very interesting in years past.
Elections will be held to determine chapter officers for next year. This will be an important factor for the future of our local chapter. All members are urged to attend.
This will be my final meeting as AMS chapter president. I hope to see you there.---Gary Ryan.
P.S. If you have not already done so, please send your email address to firstname.lastname@example.org to ease future mailings - Thanx!
May 23, 2002 Meeting
Jim discussed his latest research into the history of the Earth's atmosphere. He discussed major changes in the atmoshpere and biosphere over the past two billion years. Next, he presented information on the sun's influence on the earth's climate during the past 500 years. Finally, Jim presented a general forecast trend for the next 50 years, based on his latest solar research.
Group photo of AMS Santa Barbara/Ventura Chapter meeting May 23 at Santa Barbara CA with the speaker Jim Goodridge. Jim is second from the left.
Jim Goodridge is a former California State Climatologist. He retired in 1983, but is still employed part-time by the State Department of Water Resources. He currently maintains official datasets on rainfall in California. He is a recognized expert in the field of climatology. Jim lives with his wife Alice in Mendocino and Chico.
Jim offered CD-ROM copies of up-to-date California climate data to any persons in attendance who request these datasets!---Tom Johnston.
The Smoky Mountain Chapter had its regular bi-monthly meeting on March 18, 2002, at the Agricultural Engineering Building of the University of Tennessee - Knoxville. Dr. T. J. Blasing, of the Carbon Dioxide Information Analysis Center at Oak Ridge National Laboratory presented a talk entitled "Global Warming: Hot Air and Cold Facts."
One of our members, Dr. Wayne Davis of the Department of Civil and Environmental Engineering, at the University of Tennessee - Knoxville, has received the highest award that The University can give to one of its own faculty members, the Macebearer Award. Among other things, this means that Dr. Davis will lead the procession for this year's graduation ceremony.
Finally, the Smoky Mountain Chapter presented its annual award for the best meteorological exhibit at the 50th annual Southern Appalachian Science and Engineering Fair. Ms. Alexandra Meehan, of Knoxville, TN, was the winner. The award includes a plaque and a $100-dollar savings bond.---T.J. Blasing.
April Meeting - Wednesday April 17th, 6:30 p.m.
University of Arizona Campus
Many people are probably not aware of the prevalence or importance of snow cover in their everyday lives. In mid-winter, approximately 60% of the northern hemisphere land area can be covered in snow. 30% of the land surface of the entire globe has seasonal snow cover and 10% of the land area has permanent snow cover. Moreover, about half of the world's population depends on snow for their water supply. For example, 85% of the Colorado River's streamflow comes from snowmelt.
At the April 17th meeting of the Southeastern Arizona Chapter of the American Meteorological Society, Dr. Roger Bales from the University of Arizona's Department of Hydrology and Water Resources and Director of the Southwest Regional Earth Science Applications Center discussed a variety of techniques commonly used to remotely sense snow.
One of the ways snow can be sensed remotely is by using either active or passive microwave systems. RadarSAT, for example, is a high resolution active sensing system, which means that it both broadcasts and receives microwave signals. The satellite is in a near polar orbit and works in the 5.3 GHz frequency range. The satellite only uses horizontal polarization because, while dual polarization would be better for seasonal snow cover applications, dual polarization would require a much bigger and more expensive satellite. Dr. Bales showed measurements from the European "cousin" of RadarSAT, ERS-1, made over Greenland, which indicate wet and dry snow areas. However, without dual polarization, it is not possible to retrieve snow cover or snow/water equivalent from seasonal snowpacks.
SSM/I is a passive microwave sensor, which only detects natural microwave emissions. Data from this sensor achieves between 15 and 69 km resolution, although 30 km is the most common. Over flat ground, SSM/I data can indicate snow cover and give monthly estimates of places where there is likely snow and where snow is not likely to be on the ground. Such information is important for climate modeling.
Optical satellites can also provide information about snow. Among the satellite sensors which have been used are Ikonos, Landsat, AVHRR, and MODIS. For example, MODIS provides weekly composite snow cover maps at 0.5 km resolution using information from its 36 wavelength bands.
Airborne data can be acquired from a number of systems, including AIRSAR, which is an active multipolarization radar, PSR, and GAMMA. However, this data is necessarily limited in geographic coverage and expensive to obtain and so tends only to be used during limited field campaigns. GAMM is used operationally in the Western U.S.
The NASA Southwest Regional Earth Sciences Application Center (RESAC) is developing ways to use remotely sensed snow data for resource management and finding useful methods of merging various data sets. Among the parties interested in this endeavor are the U.S. Bureau of Reclamation, the Salt River Project, the U.S. Army Corps of Engineers, irrigation districts and flood forecasters.
The Southwest RESAC has conducted studies in the Colorado River basin and the Rio Grande basin, including the Gunnison, the San Juan, the Salt and the Verde drainage areas. As an example, Dr. Bales showed AVHRR data from 1999 depicting regions of snow and no snow. The RESAC has snow mapping algorithms, which they combine with ground truth to improve their models. Remotely measured fractional snow cover can be compared to streamflow and remote sensing data can be used to estimate maximum snow extent. For ground truth, "SNOTEL" systems, which use large fluid filled "pillows" to measure snow amounts and "snowcourse" systems, which only measure snow depth are used. Although the sampling is not representative, remote measurements of fractional snow covered area multiplied by interpolated ground based information about snow/water equivalent can help modelers and forecasters better estimate total snow water equivalent for forecasting streamflow.
Information on the Southwest RESAC can be obtained online at http://resac.hwr.arizona.edu and an example of their modeling efforts can be found online at http://hydis2.hwr.arizona.edu/resac ---Michael J. Garay.
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