ALBERT

Description: This paper presents the results of polar NO2 measurements carried out by the SME satellite during the fall and spring of 1985 and 1986 and compares the results with observations at the north pole and the results of model calculations. During the austral spring, a polar low was observed in stratospheric NO2 densities measured between 24 and 40 km, consistent with the predictions of standard photochemical theory. The geographic extent of the area of low NO2 densities was found to decrease as the hours of sunlight increased, in marked contrast to the behavior of the Antarctic ozone hole during the same period. A comparison of measurements with model calculations for NO2 imply that much of the odd nitrogen is converted to HNO3 during the polar night. Data also suggest no evidence that changes in high-altitude odd nitrogen are influencing the ozone below, or that the 'ozone hole' penetrates above 24 km to affect odd nitrogen there.

Description: We will use VHF Lightning Mapping Array data to estimate NOx per flash and per unit channel length, including the vertical distribution of channel length. What s the best way to find channel length from VHF sources? This paper presents the rationale for the fractal method, which is closely related to the box-covering method.

Description: The design of Space Station Freedom's electric power system (EPS) is reviewed, highlighting the key design goals of performance, low cost, reliability and safety. Tradeoff study results that illustrate the competing factors responsible for many of the more important design decisions are discussed. When Freedom's EPS is compared with previous space power designs, two major differences stand out. The first is the size of the EPS, which is larger than any prior system. The second major difference between the EPS and other space power designs is the indefinite expected life of Freedom; 30 years has been used for life-cycle-cost calculations.

Description: 3-dimensional lightning mapping observations obtained during the MEaPRS program in central Oklahoma during June, 1998 have been compared with observations of the discharges from space, obtained by NASA's Lightning Imaging Sensor (LIS) on the TRMM satellite. Excellent spatial and temporal correlations were observed between the two sets of observations. Most of the detected optical events were associated with intracloud discharges that developed into the upper part of the storm. Cloud-to-ground discharges that were confined to mid- and lower-altitudes tended not to be detected by LIS. Extensive illumination tended to occur in impulsive bursts toward the end or part way through intracloud flashes and appeared to be produced by energetic K-changes that typically occur at these times.

Description: During the spring and summer of 2006, a network of eight lightning mapping stations has been set up in the greater DC metropolitan area to monitor the total lightning activity in storms over Virginia, Maryland and the Washington DC area. The network is a joint project between New Mexico Tech, NASA, and NOAA/National Weather Service, with real-time data being provided to the NWS for use in their forecast and warning operations. The network utilizes newly available portable stations developed with support from the National Science Foundation. Cooperating institutions involved in hosting mapping stations are Howard University, Montgomery County Community College in Rockville MD, NOAA/NWS's Test and Evaluation Site in Sterling, VA, College of Southern Maryland near La Plata MD, the Applied Physics Laboratory of Johns Hopkins University, Northern Virginia Community College in Annandale, VA, the University of Maryland at Baltimore County, and George Mason University (Prince William Campus) in Manassas, VA. The network is experimental in that its stations a) operate in the upper rather than the lower VHF (TV channel 10, 192-198 MHz) to reduce the radio frequency background noise associated with urban environments, and b) are linked to the central processing site via the internet rather than by dedicated wireless communication links. The central processing is done in Huntsville, AL, and updated observations are sent to the National Weather Service every 2 min. The observational data will also be available on a public website. The higher operating frequency results in a decrease in signal strength estimated to be about 15-20 dB, relative to the LMA networks being operated in northern Alabama and central Oklahoma (which operate on TV channels 5 and 3, respectively). This is offset somewhat by decreased background noise levels at many stations. The receiver threshold levels range from about -95 dBm up to -80 dBm and the peak lightning signals typically extend 15-20 dB above the threshold values. Despite having decreased sensitivity, the network locates lightning in plan position over all of Maryland and Delaware, much of Virginia, and into Southern Pennsylvania and New Jersey. 3-D coverage is provided out to 100-150 km range from the Sterling WFO including the 3 major DC commercial airports (Reagan National, Dulles International, and Baltimore Washington International). The network will eventually consist of 10 or more stations, which will extend and improve its coverage.

Description: Solar Mesosphere Explorer (SME) observations of the 3 a.m. 1.27 micron nightglow at 45 N latitude are reported. From the deduced volume emission rates, the O2(a 1 Delta g) nighttime production rates for the 80-100 km altitude range are derived. Utilizing the mean SME-acquired 3 p.m. ozone profile for the same latitude and time period and an updated photochemical model, nighttime O, O3, H, OH, HO2, and H2O2 profiles are determined. These are used in calculating the rates of reactions which are sufficiently exothermic to produce O2(1 Delta) or excited states of OH or HO2, which could transfer their energy to O2 to form O2(1 Delta). Yields of O2(1 Delta) based on published laboratory and observational studies are used to find that the sum of two reaction sequences can approximate the SME measurements: (1) O + O + M and (2) H + O3 followed by OH-asterisk + O2.

Description: The United States has embarked on a major development program to have a space station operating in low earth orbit by the mid-1990s. This endeavor draws on the talents of NASA and most of the aerospace firms in the U.S. Plans are being pursued to include the participation of Canada, Japan, and the European Space Agency in the space station. From the start of the program these was a focus on the utilization of the space station for science, technology, and commercial endeavors. These requirements were utilized in the design of the station and manifest themselves in: pressurized volume; crew time; power availability and level of power; external payload accommodations; microgravity levels; servicing facilities; and the ability to grow and evolve the space station to meet future needs. President Reagan directed NASA to develop a permanently manned space station in his 1984 State of the Union message. Since then the definition phase was completed and the development phase initiated. A major subsystem of the space station is its 75 kW electric power system. The electric power system has characteristics similar to those of terrestrial power systems. Routine maintenance and replacement of failed equipment must be accomplished safely and easily and in a minimum time while providing reliable power to users. Because of the very high value placed on crew time it is essential that the power system operate in an autonomous mode to minimize crew time required. The power system design must also easily accommodate growth as the power demands by users are expected to grow. An overview of the U.S. space station is provided with special emphasis on its electrical power system.

Description: 3-dimensional lightning mapping observations were obtained in central Oklahoma during June 1998, using New Mexico Tech's Lightning Mapping Array (LMA). The results have been compared with observations of the discharges from space obtained by NASA's Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) spacecraft. Excellent spatial and temporal correlations were obtained between the two sets of observations. All discharges seen by LIS were mapped by the LMA. Most of the detected optical events were associated with lightning channels that extended into the upper part of the storm. Cloud-to-ground discharges that were confined to mid- and lower-altitudes tended to be detected by LIS at the time of late-stage return strokes. Extensive illumination tended to occur in impulsive bursts toward the end or part way through intracloud discharges and appeared to be produced by energetic K-changes that typically occur at these times.