Recent Field Projects
TELEX team members maneuver the launch tube containing the inflated balloon into position.
TELEX - Thunderstorm Electrification and Lightning Experiment
The broad objective of the TELEX spring field programs carried out in 2003 and 2004 is to learn how lightning and other electrical storm properties are dependent on storm structure, updrafts, and precipitation. TELEX used the KOUN polarimetric radar in Norman and the Oklahoma Lightning Mapping Array. The TELEX team made balloon soundings to measure the electric field profile of storms using NSSL's new mobile laboratory. They succeeded in flying fourteen balloons into nine storms on seven missions. Two of these storms were mesoscale convective systems, a specific target of TELEX. NSSL scientists are now analyzing the processed data to address the project's objectives.
BAMEX - Bow Echo and MCV Experiment
Windstorms caused by thunderstorm complexes were the focus of the 2003 Bow Echo and MCV Experiment. The mobile project had two goals: 1) to understand and improve prediction of mesoscale and storm-scale processes that produce severe winds in bowing convective systems lasting at least 4 hours, and 2) to understand how Mesoscale Convective Vortices form and the role they play in initiating and modulating convection in mesoscale convective systems. The project used aircraft to map the thermodynamic and environmental structure of convective complexes and mature MCVs. A mobile array of ground-based instruments documented the thermodynamic structure of the planetary boundary layer including convergence boundaries, surface cold pools, and surface pressure and wind variations behind the leading convective line. MCVs may be a common structural component of many large mesoscale convective systems and may be responsible for initiating new convection often resulting in heavy rainfall and flooding.
JPOLE - Joint Polarization Experiment
NSSL recently upgraded the KOUN WSR-88D radar to include polarimetric capabilities that will improve estimates of precipitation types and accumulations. These capabilities were tested as part of the Joint Polarization Experiment (JPOLE) operational demonstration, which began in the Spring of 2002. The overarching goals of JPOLE were to test the engineering design and data quality of the polarimetric KOUN WSR-88D radar, demonstrate the utility and feasibility of the radar to operational users, and collect data and information for a cost/benefit analysis. Based largely on results from JPOLE, the NEXRAD Program Management Committee agreed to upgrade the operational WSR-88D network with polarimetric capability.
IHOP 2002 - International H2O Project
Scientists from the US, France, Germany, the Netherlands and Canada took part in IHOP-2002, a weather field project in the Southern Great Plains designed to obtain more accurate and reliable measurements of moisture in the air. Scientists used NEXRAD radars, NOAA's wind profiler network and temporary wind and humidity measuring instruments. Radars, lidars and radiometers were installed on research aircraft, deployed at fixed sites or mounted onto cars and trucks. Using a variety of weather forecasting models, the quantitative precipitation forecasting effort hopes to determine if better humidity measurements will improve the models' ability to forecast rainfall. Convective initiation researchers, using mobile instruments to measure humidity in areas where storms were expected to form, hope to improve forecasts of the timing and location of new storms. Researchers focused on the atmospheric boundary layer are studying the relationship between land surface variations and air moisture variations. Finally, IHOP scientists hope the data will help determine the best combination of humidity-measuring instruments to better predict rainfall amounts.
Mobile mesonet vehicles gas up en route to intercepting the supercell thunderstorm ahead of them during the STEPS field project.
STEPS 2000 - Severe Thunderstorm Electrification and Precipitation Study
In May, June and July 2000, scientists targeted supercell thunderstorms, long-lived thunderstorms with deep rotating updrafts. Each day during the STEPS, researchers focused on one supercell storm. A T-28 armored aircraft penetrated the target storm to collect data on cloud particles and the electric field. Researchers launched balloons from several mobile sounding systems, while mobile ground units and mobile mesonet vehicles took measurements. Data was also gathered using a network of three Doppler radars, two dual-polarized radars, and a deployable lightning mapping system. STEPS scientists had three core areas of interest: how precipitation forms in supercell storms, how these storms produce electricity and lightning, and how polarimetric radars can be used to estimate the type and amount of precipitation in storms. Researchers obtained the first-ever sounding through a low-precipitation thunderstorm during STEPS. Project scientists discovered some storms had an "inverted" polarity structure, with positively-charged areas near the ground and negatively-charged areas near the top. Follow-up research might answer a key question of whether or not there is a correlation between lightning polarity and thunderstorm severity.
IPEX - Intermountain Precipitation Experiment
The Intermountain Precipitation Experiment studied winter weather across northern Utah to develop a better understanding of the structure and evolution of winter storms. During January and February 2000, scientists made detailed observations of several large storms including one that produced three feet of snow. They also made unprecedented measurements of electrification and lightning in winter storms and the first dual-Doppler radar analysis of a cold front interacting with the Great Salt Lake and surrounding mountains. Observations were made inside storms by NOAA's P-3 research aircraft and on the ground by two NSSL mobile laboratories using instrumented weather balloons. Three Doppler weather radars and a stationary microwave radiometer were deployed in northern Utah. Researchers will use the data they gathered to validate precipitation estimates from Doppler weather radars located at high elevations, to improve computer-based forecast models used in mountainous regions, and to study terrain-induced precipitation events and interactions that produce lake-effect snow bands.
